• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    ACTIVE MATERIAL OF POSITIVE ELECTRODE FOR SODIUM BATTERY, AND METHOD OF MANUFACTURING SODIUM. The invention relates to a sodium battery positive electrode active material which has a high working potential and can be charged and discharged at a high potential. The invention also relates to a method of producing this electrode positive active material, with this sodium battery positive electrode active material being represented by the general formula (1) below: NaxMy(AO4)z(P2O7)w (1 ) (where M is at least one selected from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc; A is at least one selected from the group consisting of aluminum, silicon, phosphorus, sulfur, titanium, vanadium and tungsten; x satisfies condition 4 (Greater equal) x (Greater equal) 2; y satisfies condition 4 (Greater equal) y (Greater equal) 1, z satisfies condition 4 ( Greater Equal) z (Greater Equal) 0; w satisfies the condition 1 (Greater Equal) w (Greater Equal) 0; and one or each zew is 1 or more).
    公开号:BR112014004630B1
    申请号:R112014004630-1
    申请日:2012-06-13
    公开日:2021-04-20
    发明作者:Masafumi Nose
    申请人:Toyota Jidosha Kabushiki Kaisha；
    IPC主号:
    专利说明:

    TECHNICAL FIELD
    [001] The invention relates to a positive electrode active material for a sodium battery, and a method of manufacturing this active material. BACKGROUND TECHNIQUE
    [002] Recently, with the rapid growth of information-related devices such as personal computers, video cameras and cell phones, the importance of developing improved batteries for use as power providers in these devices has been recognized. Also, in the automotive industry, advances are being made in the development of high-power, high-capacity batteries for electric cars and hybrid cars. Among the various types of batteries that exist, particular attention is paid to lithium batteries due to their high energy and power density.
    [003] In a lithium battery, the electrode positive active material is usually a lithium metal complex oxide that has a layered structure, for example, of lithium nickelate and lithium cobaltate. The negative electrode active material is typically, for example, a carbon material capable of intercalating and deintercalating lithium ions, lithium metal, or a lithium alloy. The electrolyte interposed between the positive electrode and the negative electrode is usually, for example, an electrolyte solution containing dissolved lithium salt or a solid electrolyte containing lithium.
    [004] Although lithium batteries have, as noted above, excellent energy and power density, the lithium price increase associated with increased demand for lithium batteries and the fact that lithium reserves are limited serve as obstacles to mass production and increased production.
    [005] So, a research is carried out on sodium batteries, which use sodium - whose natural deposits are abundant and which are inexpensive - instead of lithium (see, for example, Patent Document 1 and Non-Patent Documents 1 to 4).
    [006] For example, Patent Document 1 describes electrode positive active materials for non-aqueous electrolyte secondary batteries of the formula MaxMbyP2O7 (where Ma is Na, Li, Ca or Mg, Mb is a transition metal that is stably present in a valence of 4 and above, 0 <x <4, 0.5 <y <3, and 6 <z <14). In fact, what was produced and evaluated in the working examples of Patent Document 1 is MoP2O7.
    [007] Patent Document 1: Japanese Patent Application Publication No. 2004-158348
    [008] Patent Document 2: Japanese Patent Application Publication No. 2005-183395
    [009] Non-Patent Document 1: Abstract #389, 218th ECS Meeting (2010), The Electrochemical Society
    [0010] Non-Patent Document 2: LiBD-5 2011 - Electrode materials - Arcachon, France; 12-17 Jun 2011
    [0011] Non-Patent Document 3: Electrochemistry Communications, 12 (2010), 355-358
    [0012] Non-Patent Document 4: Nature Materials DOI; 10.1038/NMAT2920
    [0013] Non-Patent Document 5: Richiumu niji-denchi (Lithium secondary batteries), written and edited by Zenpachi OGUMI (Ohmsha), p. 77 SUMMARY OF THE INVENTION
    [0014] However, when the MoP2O7 produced and evaluated in the working examples of Patent Document 1 is used as the electrode positive active material in sodium batteries, a disadvantage is that the working potential is low. Also, as mentioned in Non-Patent Documents 1 to 4, the active sodium battery electrode positive materials currently in common use have a working potential of a maximum of about 3.5 V.
    [0015] Patent Document 2 describes, as an active material for lithium batteries, Li4Ni3(PO4)2(P2O7) although this is not an electrode positive active material for sodium batteries, and Non-Patent Document 5 describes LiCoO2 at a potential of about 4 V.
    [0016] Also, because the MoP2O7 that is actually produced and evaluated in Patent Document 1 does not contain Na, when this is used as the positive electrode active material in a sodium battery, the sodium battery operation must start with the insertion of Na ions (discharge reaction). Therefore, it is necessary that the electrode negative active material used together with this electrode positive active material is an active material that already contains Na. However, no Na-containing negative electrode active material that operates at a low potential and is capable of ensuring sufficient electromotive force has been reported to date, and the development of such active material for practical use faces substantial obstacles.
    [0017] This invention was carried out in light of the above circumstances. An object of the invention is to provide a sodium battery positive electrode active material that has a high working potential and can be charged and discharged at a high potential, and another object of the invention is to provide a method for producing such an active material.
    [0018] The active material of positive electrode of a sodium battery according to the invention is represented by the general formula (1) below: NaxMy(AO4)z(P2O7)w general formula (1)
    [0019] (In formula (1), M is at least one selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt ( Co), nickel (Ni), copper (Cu) and zinc (Zn); A is at least one selected from the group consisting of aluminum (Al), silicon (Si), phosphorus (P), sulfur (S) , titanium (Ti), vanadium (V) and tungsten (W); x satisfies condition 4 >x >2; y satisfies condition 4 >y >1, z satisfies condition 4 >z >0; w satisfies condition 1 >w >0; and at least one out of zew is 1 or more).
    [0020] The positive electrode active material of a sodium battery according to the invention has a high working potential and obtains high energy densification from the sodium battery.
    [0021] In the above formula (1), it is preferred that M is divalent before charging, the reason for this is that M acquires a trivalent or more highly oxidized state during charging, making it possible for the battery to operate at a high potential .
    [0022] The positive electrode active material of a sodium battery according to the invention preferably has a crystal structure that belongs to the space group Pn21a. The reason is that when the positive electrode active material has a crystal structure belonging to the Pn21a space group, all the Na ions within the crystal structure are arranged in the direction of the geometric axis a, geometric axis b or geometric axis c, that is. it is very advantageous for conducting Na ions.
    [0023] In a preferred embodiment of the positive electrode active material of a sodium battery according to the invention, M in the above formula (1) is at least one selected from the group consisting of Mn, Co and Ni, and a portion of these can be replaced by at least one element which differs from M and which is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. A sodium battery positive electrode active material according to this modality easily adopts a crystal structure that belongs to the Pn21a space group and has an excellent conductivity of Na ions.
    [0024] In a more preferred embodiment of the positive electrode active material of a sodium battery according to the invention, M in the above formula (1) is Ni, and a portion of the Ni can be replaced by at least one selected from from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cu and Zn.
    [0025] In another preferred embodiment of the positive electrode active material of a sodium battery of the invention, A in the above formula (1) is at least one selected from the group consisting of Si, P and S, and a portion thereof can be replaced by at least one element which differs from A and which is selected from the group consisting of Al, Si, P, S, Ti, V and W. According to this modality it easily adopts a crystal structure that belongs to the Pn21a space group and has an excellent conductivity of Na ions.
    [0026] In a more preferred embodiment of the positive electrode active material of a sodium battery according to the invention, A in formula (1) is P, and a portion of the P can be replaced by at least one selected from the group consisting of Al, Si, S, Ti, V and W.
    [0027] Examples of the positive electrode active material of a sodium battery according to the invention include compounds represented by the general formula Na4Ni3(PO4)2(P2O7), compounds represented by the general formula Na4Mn3(PO4)2(P2O7), compounds represented by the general formula Na4Co3(PO4)2(P2O7), compounds represented by the general formula Na4Co(3-a)Mna(PO4)2(P2O7) (where "a" satisfies the condition 0.3 <a <0.8) and the compounds represented by the general formula Na4Co(3-bc)MnbNic(PO4)2(P2O7) (where "b" satisfies the condition 0.3 <b < 1.0, and "c" satisfies the condition 0.3 < c < 1.0).
    [0028] The inventive method for producing the positive electrode active material of a sodium battery includes:
    [0029] a pre-burning step for burning a mixture of starting material containing at least one Na-containing compound, an M-containing compound above M, an A-containing compound above and a P-containing compound in a outdoor atmosphere at 150 to 500°C; and
    [0030] a main firing step to burn the pre-burned material thus obtained in an open-air atmosphere at 500 to 800°C after implementing the pre-burning step.
    [0031] The inventive method for producing a positive electrode active material of a sodium battery may further include, before the pre-burning step, the step of size reduction of the compound containing Na, the compound containing M, the compound containing A and the compound containing P.
    [0032] This invention allows a sodium battery positive electrode active material that has a high working potential and can be charged and discharged at a high potential to be supplied. Using the inventive positive electrode active material of sodium batteries, it is possible to obtain high energy densities in sodium batteries. BRIEF DESCRIPTION OF THE DRAWINGS
    [0033] [Figure 1] Figure 1 shows the crystal structure of the Pn21a space group, as observed from the geometric axis direction a.
    [0034] [Figure 2] Figure 2 shows the crystal structure of the Pn21a space group, as observed from the geometric axis direction b.
    [0035] [Figure 3] Figure 3 shows the crystal structure of the Pn21a space group, as observed from the geometric axis direction c.
    [0036] [Figure 4] Figure 4 is a schematic cross-sectional view showing one embodiment of a sodium battery.
    [0037] [Figure 5] Figure 5 shows an XRD pattern of the electrode positive active material synthesized in Example 1.
    [0038] [Figure 6] Figure 6 shows the results of CV measurements, with Na metal acting as the counter electrode, of a positive electrode fabricated using the positive electrode active material synthesized in Example 1.
    [0039] [Figure 7] Figure 7 shows the XRD pattern of the electrode positive active material synthesized in Example 2.
    [0040] [Figure 8] Figure 8 shows the charge discharge characteristics (energy density versus potential) of a positive electrode fabricated using the positive electrode active material synthesized in Example 2.
    [0041] [Figure 9] Figure 9 is an XRD pattern of the electrode positive active material synthesized in Example 3.
    [0042] [Figure 10] Figure 10 shows the charge discharge characteristics (energy density versus potential) of a positive electrode fabricated using the positive electrode active material synthesized in Example 3.
    [0043] [Figure 11] Figure 11 shows the cycle performance (number of cycles versus charge discharge energy density) of a positive electrode fabricated using the positive electrode active material synthesized in Example 3.
    [0044] [Figure 12] Figure 12 shows the charge discharge characteristics (energy density versus potential) of a positive electrode fabricated using the positive electrode active material synthesized in Example 3.
    [0045] [Figure 13] Figure 13 shows the results of evaluations on the charge discharge characteristics of positive electrodes fabricated using the positive electrode active materials synthesized in Examples 4 to 8.
    [0046] [Figure 14] Figure 14 shows the discharge curves of positive electrodes fabricated using positive electrode active materials synthesized in Examples 4 to 8.
    [0047] [Figure 15] Figure 15 shows the cycle performances of positive electrodes fabricated using the positive electrode active materials synthesized in Examples 4 to 8.
    [0048] [Figure 16] Figure 16 shows the results of evaluations on the charge discharge characteristics of positive electrodes fabricated using the positive electrode active materials synthesized in Examples 9 to 12. WAYS TO CARRY OUT THE INVENTION
    [0049] The inventive positive electrode active material of a sodium battery and (sometimes referred to below simply as the "positive electrode active material") and the inventive method for producing the same are described in detail below. [Positive Sodium Battery Electrode Active Material]
    [0050] The active material of positive electrode of a sodium battery of the invention is characterized by having the general formula (1) below. NaxMy(AO4)z(P2O7)w general formula (1)
    [0051] (In formula (1), M is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn; A is at least one selected from group consisting of Al, Si, P, S, Ti, V and W; x satisfies condition 4 >x >2; y satisfies condition 4 >y >1, z satisfies condition 4 >z >0; w satisfies condition the condition 1 >w >0; and at least one out of zew is 1 or more.)
    [0052] As described above, the active electrode positive materials of conventional sodium batteries have a working potential of about 3.5 V or less, as a result of which sodium batteries of sufficient energy density have not been obtained.
    [0053] When Li in an active material of a lithium battery is replaced by Na, the working potential tends to be considerably reduced. For example, as mentioned in Non-Patent Document 5 above, LiCoO2 has a potential of about 4 V, while, as mentioned in Non-Patent Document 4, the average potential of Na(x)CoO2 is about 2.9 V , which is significantly less than that of LiCoO2.
    [0054] Also, due to the fact that Na ions have a larger ionic radius than Li ions, when Li in an active material containing Li is replaced by Na, it is considered that the movement of Na ions becomes difficult.
    [0055] For reasons like these, the common sense is that a useful active material of sodium batteries that works at a high potential cannot be obtained simply by replacing the lithium in an active material of lithium batteries with sodium.
    [0056] However, the inventors conducted extensive investigations, finally finding that the compound of the formula Na4Ni3(PO4)2(P2O7) can be used as a positive electrode active material of a sodium battery, and furthermore works on potentials very high as 4.6 to 4.9 V. Furthermore, due to the decomposition of the electrolyte solution used together with the positive electrode active material, these potentials of 4.6 to 4.9 V can be suppressed by using the active material of the positive electrode of the invention, it is possible to obtain a sodium battery that exhibits stable battery characteristics over an extended period of time. The inventor has also found that the compound of the formula Na4Mn3(PO4)2(P2O7), the compound of the formula Na4Co3(PO4)2(P2O7), the compound of the formula Na4Co(3-a)Mna(PO4)2(P2O7), and the compound of formula Na4Co(3-b-c)MncNic(PO4)2(P2O7) are capable of use as electrode positive active materials for sodium batteries and work at high potentials in excess of 4V.
    [0057] Furthermore, the active electrode positive materials of the invention are capable of functioning at high potentials even at the relatively low temperature of 25°C.
    [0058] The compounds of the above general formula (1) NaxMy(AO4)z(P2O7)w, as per the above compound Na4Ni3(PO4)2(P2O7), are capable of functioning at a high potential as the electrode active material positive of a sodium battery. The reason is considered as set out below.
    [0059] In the general formula (1), M is an electrochemically active transition metal with a valence of 2 or more, and is Ni or a metal that has an ionic radius close to that of Ni.
    [0060] In the general formula (1), A is P or an element that, like P, easily adopts a tetrahedral structure. Here, "tetrahedral structure" refers to a structure in the form of a tetrahedron that has four oxygen atoms at the vertices and contains, in a gap within the tetrahedron, a single A atom that is covalently bonded to the four oxygen atoms.
    [0061] In relation to the polyanionic portions (AO4) and (P2O7), provided that at least one of the subscripts z that represents the constitutional reason of (AO4) and w that represents the constitutional reason of (P2O7) in the positive electrode active material is 1 or more, the resulting electrode positive active material is believed to function at a high potential due to inductive effects on the MO bonds by at least one of the (AO4) and (P2O7) moieties. "Inductive effects" means that, due to the high covalent binding capacity of the AO bonds that make up (AO4) and the PO bonds that make up (P2O7), the electrons from the MO bonds are attracted to the AO bond and PO bond side, to covalent binding capacity between M and O decreases, and the energy gap of the hybrid orbital becomes smaller, as a result, the redox level of M is reduced, the energy difference with sodium becomes larger, and the redox potential in relation to sodium it increases.
    [0062] The composition of the inventive positive electrode active material is described in detail below.
    [0063] In the positive electrode active material of the invention, M is at least one kind of metal selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn. Among these, a metal that is divalent in the state before loading is preferred. This is because, in cases where M is a kind of metal that is divalent in the state before loading, this kind of metal takes on a highly oxidized state that has a valence of 3 or more during loading, allowing the active material to function in a high potential.
    [0064] Among these above metal pieces, M is preferably at least one selected from the group consisting of Mn, Co and Ni. This is because Mn, Co and Ni are divalent in the state before charging and because Mn and Co are capable of forming crystal structures similar to those of Ni. In the general formula above (1) NaxMy(AO4)z(P2O7)w, M can be Ni, M or Co. In cases where the remainder of the composition (the values of x, y, zew, and also A) is equal, it is confirmed that the compound has the same crystal structure.
    [0065] Some portion of these Mn, Co and Ni can be replaced by at least one element that differs from M (which is at least one selected from Mn, Co and Ni) which is selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn.
    [0066] When M in the above formula (1) is Ni, an active electrode positive material that has a high electronic conductivity can be obtained. It is believed that the reason is this, in cases where the redox element, that is, the element that performs the donation and acceptance of electrons, is Ni, with the extraction of Na ions during charging, in oxides of complex Ni which have a common olivine-like crystal structure, Ni ions change from a divalent state to a trivalent state. In contrast, in the positive electrode active material of the invention, the Ni ions change from a divalent state to a higher trivalent state (for example, in the case of Na4Ni3(PO4)2(P2O7), a valence of about 3.3 ), and then a larger number of electrons migrate. Ni can be replaced by at least one species selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Cu and Zn.
    [0067] When M in the above formula (1) is Mn, compared to when M = Ni, a positive electrode active material that has a high reversibility of crystal structure and high stability during charging and discharging, and also has a potential of relatively low work, can be obtained. Due to the fact that the working potential is relatively low, the decomposition and deterioration of the electrolyte solution can be further suppressed. Then, when M is Mn, compared to when M = Ni, the crystal structure reversibility and stability are increased and the deterioration of the electrolyte solution is reduced, allowing a high cycle performance to be obtained. Some portion of Mn can be replaced by at least one selected from the group consisting of Ti, V, Cr, Fe, Co, Ni, Cu and Zn.
    [0068] When M in the above formula (1) is Co, compared to when M = Ni, an electrode positive active material that has a high reversibility of crystal structure and high stability during loading and unloading and also has a working potential relatively low, can be obtained. Due to the fact that the working potential is relatively low, the decomposition and deterioration of the electrolyte solution can be further suppressed. Furthermore, when M is Co, due to the improved reversibility of crystal structure, improved stability and suppressive effects of electrolyte solution deterioration, the electrode positive active material is capable of exhibiting significant reversible capability. So when M is Co, compared to when M = Ni, the battery is able to get excellent cycle performance and excellent capacity performance.
    [0069] Some portion of Co can be replaced by at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Ni, Cu and Zn.
    [0070] When M in the above formula (1) is Co and a portion of Co is replaced by Mn, an even better capacity performance can be exhibited than when M is Co individually. This is believed to be the reason why, by replacing a portion of the Co2+ sites with Mn2+, the replaced Mn2+ can have the charge compensated not only for Mn2+/3+, but also for Mn3+/4+. Furthermore, some portion of Co and Mn can be replaced by at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn.
    [0071] When M in the above formula (1) is Co and a portion of Co is replaced by Mn and Ni, an even greater working potential can be exhibited than when a portion of Co is replaced by Mn individually. It is believed that the reasons are that the Mn2+ replaced by having the charge compensated not only for Mn2+/3+, but even for Mn3+/4+, and also that some Co is replaced by Ni, for this the charge compensation (Ni2+ ^ Ni3+) at a high potential proceeds more easily than for Co. Some portion of Co, Mn, and Ni can be replaced by at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co , Ni, Cu and Zn.
    [0072] In the positive electrode active material of the invention, A is at least one selected from the group consisting of Al, Si, P, S, Ti, V and W, and is more preferably at least one selected from the group consisting of Si, P and S. The reason is that Si, P and S easily form a tetrahedral structure in particular, and Si and S are able to form a crystal structure similar to that of P. Among these, A is most preferably P. Some portion of Si, P and S can be replaced by at least one element that differs from A (ie at least one selected from Si, P and S) and is selected from the group consisting of Al, Si, P, S, Ti, V and W.
    [0073] In formula (1), x satisfies condition 4 >x >2, y satisfies condition 4 >y >1, z satisfies condition 4 >z >0, w satisfies condition 1 >w >0, and at least one out of zew is 1 or more.
    [0074] In cases where zew are 1 or more, because the polyanionic portion includes an AO4 and P2O7 tetrahedron that shares an oxygen with the AO4 tetrahedron, the inductive effect on the MO bonds is considerable, this has the desired effect of allowing a positive electrode active material that has a higher potential is obtained.
    [0075] In this invention, an especially preferred positive electrode active material is the compound of the formula Na4Ni3(PO4)2(P2O7). Due to the fact that Na4Ni3(PO4)2(P2O7) includes Ni as a redox element and the polyanionic portion includes (PO4) and (P2O7), along with a high electronic conductivity as noted above, this compound has the ability to work in a high potential due to a high inductive effect.
    [0076] Furthermore, Na4Ni3(PO4)2(P2O7) has a crystal structure that belongs to the Pn21a space group. Figures 1 to 3 show the crystal structure (Na4Ni3(PO4)2(P2O7)) that belongs to the space group Pn21a in a view from the axis direction a (figure 1), a view from the axis direction geometry b (figure 2), and a view from the geometry axis direction c (figure 3). Using Na4Ni3(PO4)2(P2O7) for the purpose of illustration, figures 1 to 3 show a crystal structure that belongs to the Pn21a space group. However, in figures 1 to 3, when replacing Ni with another metal species represented by M above (eg Co or Mn), the crystal structure of another positive electrode active material that has a crystal structure that belongs to the space group Pn21a is displayed.
    [0077] As it is visible from figures 1 to 3, in the crystal structure that belongs to the Pn21a space group, all Na ions in the crystal structure are arranged in the direction of the geometric axis a, geometric axis b or geometric axis c, resulting in very high Na ion mobility. That is, the crystal structure that belongs to the Pn21a space group is highly advantageous for carrying Na ions, as a result of this, the insertion and extraction of Na ions proceeds easily.
    [0078] For reasons such as these, it is preferred that the active electrode positive material of the invention has a crystal structure that belongs to the Pn21a space group.
    [0079] In this invention, additional examples of especially preferred positive electrode active materials include compounds of the general formula Na4Mn3(PO4)2(P2O7), compounds of the general formula Na4Co3(PO4)2(P2O7), compounds of the general formula Na4Co(3 - a)Mna(PO4)2(P2O7) and compounds of the general formula Na4Co(3-b-c)MnbNic(PO4)2(P2O7). These compounds have crystal structures that belong to the Pn21a space group shown in figures 1 to 3.
    [0080] As already mentioned, the compound Na4Mn3(PO4)2(P2O7) that contains Mn as the redox element (M), by improving the crystal structure reversibility, improving stability and suppressing the deterioration of the electrolytic solution, is able to display a high cycle performance.
    [0081] As already mentioned, compounds of the general formula Na4CO3(PO4)2(P2O7) that contain Co as the redox element (M), by improving the reversibility of crystal structure, improving stability, suppressing the deterioration of the electrolyte solution and increase reversible capacity, are able to exhibit excellent cycle performance and excellent capacity performance.
    [0082] Also, as already mentioned above, compounds of the formula Na4CO(3-a)Mna(PO4)2(P2O7) which include Co as the redox element (M) and in which some portion of the Co is replaced by Mn, by charge compensation due to Mn, they are able to exhibit an even better capacity performance than Na4Co3(PO4)2(P2O7).
    [0083] In compounds of the general formula Na4CO(3-a)Mna(PO4)2(P2O7), the subscript 'a' representing the amount of substitution of Mn should be a number less than 3, is preferably within the range of 0.01 < a < 0.8, and is more preferably in the range of 0.3 < a < 0.8, with the subscript 'a' being more preferably 0.6.
    [0084] Furthermore, as already mentioned above, in compounds of the general formula Na4CO(3-bc)MnbNic(PO4)2(P2O7) which include Co as the redox element (M) and in which some portion of the Co is replaced by Mn and Ni, the charge compensation effect due to Mn and, additionally, the charge compensation effect in the high potential region due to Ni allow these compounds to exhibit a high working potential compared to Na4CO(3-a)Mna( PO4)2(P2O7).
    [0085] In the compounds of the general formula Na4CO(3-b-c)MnbNic(PO4)2(P2O7), the subscript 'b' representing the substitution amount of Mn and the subscript 'c' representing the substitution amount of Ni should be such that the sum (b+c) is a number less than 3, and are preferably within the ranges 0.01 <b < 1.0 and 0.01 <c < 1.0, and more preferably within of the ranges 0.3 <b <1.0 and 0.3 <c <1.0. [Production Method of Electrode Positive Active Material]
    [0086] The method of producing the electrode positive active material of the invention is not particularly limited, although an example of a preferred method is one in which the electrode positive active material of the invention is produced as described below.
    [0087] The inventive method of producing a positive electrode active material of a sodium battery is characterized by including, in order:
    [0088] a pre-burning step involving the burning of a starting material mixture containing at least one Na-containing compound, a M-containing compound, an A-containing compound and a P-containing compound in an open-air atmosphere at 150 to 500°C; and
    [0089] a main burn step that involves burning the pre-fired material in an open air atmosphere at 500 to 800°C.
    [0090] As mentioned above, a single-phase positive electrode active material can be synthesized first by pre-burning a starting material mixture at a temperature of 150 to 500°C which is lower than in the main burning step, then performing a main firing step at 500 to 800°C so that the reaction proceeds uniformly.
    [0091] Each step in the inventive method of producing an electrode positive active material is described successively below. (Pre-Fire Stage)
    [0092] In the pre-burning step, a mixture of starting material that contains at least one Na-containing compound, a M-containing compound, an A-containing compound and a P-containing compound is burned in an open-air atmosphere at 150 °C 500°C.
    [0093] The Na-containing compound, the M-containing compound, the A-containing compound and the P-containing compound are the starting materials of the positive electrode active material NaxMy(AO4)z(P2O7)w, and serve as, respectively, the Na source, M source, A source, and P source.
    The Na-containing compound, the M-containing compound, the A-containing compound and the P-containing compound can be suitably selected without particular limitation. These respective compounds can be of one type used singly, or of two or more types used in combination. Alternatively, a single compound may include two or more of Na, M, A and P. In cases where M and A include common atoms, the compound containing M and the compound containing A may be the same compound. In cases where A is P, the compound containing A and the compound containing P may be the same compound.
    [0095] Illustrative examples of Na-containing compounds that serve as the source of Na include Na2CO3, Na2O, Na2O2, Na3PO4, Na4P2O7 and CH3COONa.
    [0096] Illustrative examples of M-containing compounds that serve as the source of M include Ti-containing compounds such as TiO2 and Ti2O3, V-containing compounds such as V2O3, V2O5 and NH4VO3, Cr-containing compounds as Cr2O3 and Cr(NO3)3, Mn-containing compounds such as MnCO3 and (CH3COO)2Mn, Fe-containing compounds such as FeO, Fe2O3 and Fe(NO3)3, Co-containing compounds such as CoCO3, (CH3COO)2Co, CoO and Co2O3, Ni-containing compounds such as (CH3COO)2Ni, NiCO3 and NiO, compounds containing Cu such as (CH3COO)2Cu and CuO, and compounds containing Zn such as (CH3COO)2Zn and ZnO.
    [0097] Illustrative examples of A-containing compounds that serve as the source of A include Al-containing compounds such as Al(NO3)3, Al2O3 and Al(OH)3, Si-containing compounds such as SiO2 and SiO, P-containing compounds such as NH4H2PO4, ( NH4)2HPO4, H3PO4, Na2P2O7 and Na3PO4, compounds containing S such as (NH4)2SO4, Na2SO4 and H2SO4, compounds containing Ti such as TiO2 and Ti2O3, compounds containing V such as V2O3, V2O5 and NH4VO3, and compounds containing W such as WO3 and Na2WO4.
    [0098] Illustrative examples of P-containing compounds that serve as the source of P include NH4H2PO4, (NH4)2HPO4, H3PO4, Na4P2O7 and Na3PO4.
    In the starting material mixture, the mixing ratios of Na-containing compound, M-containing compound, A-containing compound and P-containing compound above can be suitably adjusted according to the subscripts x, y, zew in the compound NaxMy(AO4 )z(P2O7)w which is synthesized. Typically, the respective compounds can be mixed so that the proportions (molar ratio) of Na, M, A and P in the starting material mixture satisfy the condition Na : M : A : P = x : y : z : 2w.
    [00100] No particular limitation is imposed on the method of preparing the starting material mixture. For example, use can be made of any suitable mixing method or method of agitation.
    [00101] Although the particle sizes of the respective compounds in the starting material mixture are not particularly limited, as it is desired that the contact surface area between the particles be large so that the reaction proceeds uniformly, it is preferred to subject each compound to size reduction before pre-burning. That is, prior to pre-burning, it is preferred to provide a size reduction step that reduces the particle sizes of the Na-containing compound, the M-containing compound, the A-containing compound and the P-containing compound within the starting material mixture. . In the size reduction step, the size reduction of compounds can be carried out on a plurality of compounds at the same time, or it can be carried out individually on each compound. Furthermore, no particular limitations are imposed on the size reduction method in the size reduction step. Any size reduction method can be used; further use can be made of a method which combines mixing and agitation of the starting material mixture with size reduction. For example, a ball mill, granule mill or the like is capable of mixing and agitating the starting material mixture while also subjecting the mixture to size reduction.
    [00102] The temperature in the pre-burn step is lower than the temperature in the main burn step, and should be in the range of 150 to 500°C, preferably 180 to 450°C, and more preferably 250 to 350°C. The pre-burn time is not particularly limited and can be suitably adjusted, for example, to about 1 to about 5 hours.
    [00103] The outdoor atmosphere that serves as the atmosphere in the pre-burn step refers here to a gas atmosphere containing oxygen. (Main firing stage)
    [00104] In the main firing step, the pre-fired material obtained in the pre-burning step is fired in an open air atmosphere at 500 to 800°C.
    [00105] The firing temperature in the main firing step is preferably 550 to 750°C. The firing time in this step is not particularly limited and can be suitably adjusted, for example, to about 1 to about 30 hours.
    [00106] The outdoor atmosphere that serves as the atmosphere in the main flare step is similar to the outdoor atmosphere in the pre-burn step. (Other Production Methods)
    [00107] The method of producing the inventive positive electrode active material is not limited to the above method. For example, production is also possible by a method in which, first, a compound containing Nas that serves as the source of Na, a compound containing M that serves as the source of M, an A-containing compound that serves as the the source of A and a compound containing P that serves as the source of P are dissolved and heated, together with a gelling agent, in an acidic solution to prepare a gel, after which the resulting gel is burnt in an open atmosphere.
    [00108] In this method, the Na-containing compound, the M-containing compound, the A-containing compound and the P-containing compound can be suitably selected, provided they are soluble in an acidic solution. These respective compounds can be of one type used singly, or of two or more types used in combination. Alternatively, a single compound may include two or more of Na, M, A and P. In cases where M and A include common atoms, the compound containing M and the compound containing A may be the same compound. In cases where A is P, the compound containing A and the compound containing P may be the same compound.
    [00109] Illustrative examples of Na-containing compound include Na4P2O7, CH3COONa, Na2CO3, Na2O and Na2O2.
    [00110] Illustrative examples of M-containing compounds include Ti-containing compounds as Ti(NO3)4, TiO2 and Ti2O3, V-containing compounds as V2O3 and V2O5, Cr-containing compounds as Cr(NO3)3, Mn-containing compounds as (CH3COO)2Mn and MnCO3, Fe-containing compounds such as Fe(NO3)3, FeC2O4 and (CH3COO)3Fe, Co-containing compounds such as (CH3COO)2Co, CoCO3, Co2O3 and CoO, Ni-containing compounds such as (CH3COO)2Ni, NiO and NiCO3, containing compounds Cu as (CH3COO)2Cu, and compounds containing Zn as (CH3COO)2Zn.
    [00111] Illustrative examples of A-containing compounds include Al-containing compounds such as Al(NO3)3, Si-containing compounds such as Si(OCH2CH3)4, P-containing compounds such as NH4H2PO4, (NH4)2HPO4 and H3PO4, S-containing compounds such as H2SO4 and Na2SO4, Ti-containing compounds such as Ti(NO3)4, TiO2 and Ti2O3, V-containing compounds such as V2O3 and V2O5, and W-containing compounds such as WO3 and Na2WO4.
    [00112] Illustrative examples of P-containing compounds include NH4H2PO4, (NH4)2HPO4 and H3PO4.
    [00113] The mixing ratios of the Na-containing compound, the M-containing compound, the A-containing compound and the above P-containing compound can be suitably adjusted according to the subscripts x, y, zew in the compound NaxMy(AO4)z(P2O7 )w which is synthesized. Typically, the respective compounds can be mixed so that the proportions (molar ratio) of Na, M, A and P in the starting material mixture satisfy the condition Na : M : A : P = x : y : z : 2w.
    [00114] The gelling agent can be, for example, glycolic acid. The acidic solvent can be, for example, an aqueous solution of nitric acid.
    [00115] The heating temperature during gel preparation must be such as to make each of the above several compounds dissolve in the acidic solution and allow the preparation of a gel, and can be adjusted, for example, to 60 to 120 °C.
    [00116] The gel burning temperature can be adjusted to 500 to 800°C, and preferably from 550 to 750°C. The outdoor atmosphere during gel firing is similar to the outdoor atmosphere in the pre-burn step above. [Sodium Battery]
    [00117] The electrode positive active material provided by this invention can be advantageously used as an electrode positive active material in a sodium battery. The sodium battery can be a primary battery or a secondary battery. Using a secondary sodium battery as an illustration, a description is provided below of a sodium battery using the electrode positive active material provided by this invention.
    [00118] Figure 4 is a schematic cross-sectional diagram that shows a modality of a secondary sodium battery. As shown in Figure 4, the secondary sodium battery 8 generally has a structure in which an electrolytic layer 3 is disposed between a negative electrode 1 and a positive electrode 2. The negative electrode 1 has a negative electrode 4 active material layer containing a negative electrode active material, and a negative electrode 5 current collector that performs charge collection from the negative electrode active material layer 4. The positive electrode 2 has a positive electrode active material layer 6 containing an active material electrode positive, and a positive electrode 7 current collector that performs charge collection from the active material layer of positive electrode 6.
    [00119] In the following paragraphs, each battery structure will be explained.
    [00120] The negative electrode contains a negative electrode active material capable of insertion and extraction of sodium ions. The negative electrode generally has a negative electrode active material layer that includes at least one negative electrode active material. When required, this also has a negative electrode current collector that performs charge collection from the negative electrode active material layer.
    [00121] Illustrative examples of negative electrode active material include hard carbon, Na metal and tin.
    [00122] The negative electrode active material layer may contain only a negative electrode active material or, in addition to the negative electrode active material, may also contain a binder, a conductive material, an electrolyte and the like. For example, in cases where the electrode negative active material is in the form of a sheet or metal foil, this can become a negative electrode layer that contains only the negative electrode active material. On the other hand, in cases where the electrode negative active material is in the form of a powder, this can become a negative electrode layer that includes a binder in addition to the negative electrode active material.
    [00123] Illustrative examples of the binder include polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE) and styrene butadiene rubber (SBR). Illustrative examples of the conductive material include carbon materials such as carbon black, activated carbon, carbon fibers (eg carbon nanotubes, carbon nanofibers), and graphite.
    [00124] The positive electrode contains a positive electrode active material capable of insertion and extraction of sodium ions. The positive electrode generally has a positive electrode active material layer that includes at least one positive electrode active material. When required, this also has a positive electrode current collector that performs charge collection from the positive electrode active material layer.
    [00125] The electrode positive active material used may be the electrode positive active material described above of the invention or it may be an electrode positive active material produced by the production method of the invention.
    [00126] As with the negative electrode active material layer, the positive electrode active material layer may contain only a positive electrode active material or it may also, in addition to the positive electrode active material, contain a conductive material, a binder , an electrolyte, an electrode catalyst and the like. Due to the fact that materials similar to those in the negative electrode active material can be used as the conductive material and binder in the positive electrode active material, descriptions of these are omitted below.
    [00127] In the case of the negative electrode active material layer and the positive electrode active material layer, the electrolytic active material layer can be formed using any suitable coating method, such as dip coating, spray coating, spray coating. roller, doctor blade coating, gravure coating or screen coating, for coating, drying, and optionally laminating, slurries containing the respective materials.
    [00128] The positive electrode current collector and the negative electrode current collector are not subject to any particular limitations in relation to material, structure or shape, provided that these are materials that have the desired electronic conductivity and do not cause reactions with sodium ion in the environment inside the battery.
    [00129] Illustrative examples of the material that constitutes the positive electrode current collector include metal materials such as stainless steel, nickel, aluminum, iron, titanium and copper, carbon materials such as carbon fibers and carbon paper, and ceramic materials that have a high electronic conductivity, such as titanium nitride. It is possible that the battery housing also serves as the electrode positive current collector.
    [00130] Illustrative examples of the material that constitutes the negative electrode current collector include copper, stainless steel, nickel and aluminum. It is possible that the battery housing also serves as the negative electrode current collector.
    [00131] The electrode positive current collector and the electrode negative current collector can be in the form, for example, of a sheet, metal sheet or mesh. Naturally, a network is preferred.
    [00132] The electrolyte layer includes at least one electrolyte that allows the conduction of sodium ions between the positive electrode and the negative electrode.
    [00133] The electrolyte must be one that has conductivity of sodium ions and is exemplified by electrolyte solutions, gel-type electrolytes obtained by gelling an electrolyte solution with a polymer or similar, and solid electrolytes.
    [00134] Examples of electrolyte solutions having sodium ion conductivity include the electrolyte solutions obtained by dissolving a sodium salt in an aqueous solvent or a non-aqueous solvent.
    [00135] Illustrative examples of non-aqueous solvent include, but are not particularly limited to, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC) and fluoroethylene carbonate (FEC), cyclic esters such as y-butyrolactone (GBL ), and acyclic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC). These non-aqueous solvents can be used singly or two or more can be used in combination. Alternatively, a nitrile compound having a CN group attached to the end of an acyclic saturated hydrocarbon compound can be used in admixture with a non-aqueous solvent. By adding a nitrile compound to a non-aqueous solvent-type electrolyte solution, a stable non-aqueous solvent-based electrolyte solution can be obtained that is stable and does not decompose even in a high potential region such as that where the active material of invention's sodium batteries positive electrode works.
    [00136] Illustrative examples of the sodium salt include, but are not particularly limited to, NaPF6, NaBF4, NaClO4, NaCF3SO3, (CF3SO2)2NNa, NaN(FSO2) and NaC(CF3SO2)3. These sodium salts can be used individually, or two or more can be used in combination. NaPF6, which is also stable at high potentials, is especially preferred.
    [00137] No particular limitation is imposed on the concentration of the sodium salt in the non-aqueous electrolyte solution.
    [00138] The non-aqueous electrolytic solution can also be used after gelling by adding a polymer. The non-aqueous electrolyte solution gelling method is exemplified by a method involving the addition of a polymer such as polyethylene oxide (PEO), polyacrylonitrile (PAN), PVdF or polymethyl methacrylate (PMMA) to a non-aqueous electrolyte solution.
    [00139] In cases where an electrolyte solution is used as the electrolyte, isolation between the positive electrode and the negative electrode can be accomplished by disposing a porous insulating body as a separator between the positive electrode and the negative electrode, and by impregnating the separator with the electrolyte solution. The separator is exemplified by porous membranes such as porous polyethylene membranes and porous polypropylene membranes; and non-woven materials such as resin non-woven materials and fiberglass non-woven materials.
    [00140] The battery housing used to house the negative electrode, the electrolytic layer and the positive electrode may be one that has a common shape, such as a coin-like battery housing, flat plate type, tubular or laminated type.
    [00141] In batteries that have a construction in which laminates of a positive electrode, an electrolytic layer and a negative electrode arranged in that order are repeatedly stacked in multiple layers, from a safety point of view, separators composed of an insulating material can be provided between adjacent positive and negative electrodes. Illustrative examples of such separators include porous membranes such as porous polyethylene membranes and porous polypropylene membranes; and non-woven materials such as resin non-woven materials and fiberglass non-woven materials.
    [00142] Furthermore, terminals that serve as connectors to the external part can be provided on the current collectors of the respective electrodes. [Example 1] (Synthesis of Sodium Battery Positive Electrode Active Material)
    [00143] Na2CO3 (Na-containing compound), (CH3COO)2Ni (Ni-containing compound) and NH4H2PO4 (P-containing compound) were mixed in a molar ratio of Na : Ni : P = 4 : 3 : 4. The mixture was reduced by size using a ball mill, after that the pre-burn was carried out in an open air atmosphere at 300°C, and the main burn was carried out for 15 hours at 700°C.
    [00144] The crystal structure of the synthesized material obtained in the main firing step was analyzed with a ray diffractometer (XRD). The results are shown in Figure 5. The upper half of Figure 5 shows the XRD pattern of the synthesized material, and the lower half shows the XRD pattern of Na4Ni3(PO4)2P2O7 in the ICSD database (ICSD No. 01-087-0977 ). It was possible to confirm from Figure 5 that the synthesized material obtained is Na4Ni3(PO4)2P2O7. Furthermore, it was confirmed that this synthesized material (Na4Ni3(PO4)2P2O7) has a crystal structure belonging to the Pn21a space group. (Evaluation of Sodium Battery Electrode Positive Active Material) <Positive Electrode Manufacturing>
    [00145] A slurry was prepared by mixing Na4Ni3(PO4)2P2O7 (positive electrode active material) obtained in Example 1, carbon (conductive additive) and PVdF (binder) in the weight ratio 75 : 20 : 5, then dispersing the mixture in N-methyl-2-pyrrolidone (dispersant).
    [00146] This slurry was coated on an aluminum sheet (current collector), dried and laminated, thus producing a positive electrode constituted, as successive layers, of the current collector and the active material layer of the positive electrode. <Test Cell Manufacturing>
    [00147] First, a counter electrode was obtained by perforating a sheet of sodium metal with a matrix.
    [00148] In a separate procedure, a sodium salt (NaPF6) was added to a mixed solvent obtained by mixing EC and DMC in a volume ratio of 1 : 1, thus providing a non-aqueous electrolytic solution having a sodium concentration of 1.0 mol/dm3.
    [00149] The positive electrode manufactured as described above, a porous membrane (separator) consisting of a porous polypropylene membrane, a porous polyethylene membrane and a porous polypropylene membrane arranged as successive layers in that order, and a counter electrode were stacked in that order . The positive electrode is arranged inside the stack so that the active material layer of the positive electrode is located on the separator side of this.
    [00150] The non-aqueous solvent electrolyte solution described above was impregnated into the stack separator above, thus producing a coin-type test cell. <Assessment Method>
    [00151] Cyclic voltammetry (CV) was performed under the following conditions using the above test cell. The results are shown in figure 6. • Potential range: Open circuit voltage (OCV) at 4.9 V • Sweep rate: 0.2 mV/s • Temperature: 25°C
    [00152] As shown in figure 6, the peaks of the oxidation reaction that correspond to the charging and the reduction reaction that corresponds to the discharge were confirmed in the region of ultra-high potential from 4.6 to 4.9 V, in the first cycle and in the second cycle. Thus, it was confirmed that the synthesized material obtained in Example 1 can be used as the positive electrode active material of a secondary sodium battery, and even that it operates at a high potential. Furthermore, the ability to operate at a high potential as described above was exhibited at the low temperature of 25°C. [Example 2] (Synthesis of Sodium Battery Positive Electrode Active Material)
    [00153] Na4P2O7 (compound containing Na and P), (CH3COO)2Mn (compound containing Mn) and NH4H2PO4 (compound containing P) were added, together with glycolic acid (gelling agent), to an acidic solution (aqueous solution of nitric acid ) in a molar ratio of Na : Mn : P = 4 : 3 : 4 and dissolved, and the solution was stirred at 80°C. The resulting gel was burnt in an open air atmosphere at 700°C for 15 hours.
    [00154] The crystal structure of the synthesized material obtained by burning was analyzed with an XRD. The results are shown in figure 7. From figure 7, it is confirmed that the resulting synthesized material is Na4Mn3(PO4)2P2O7. It was confirmed that the resulting synthesized material (Na4Mn3(PO4)2P2O7) has a crystal structure that belongs to the Pn21a space group shown in Figures 1 to 3. (Sodium Battery Positive Electrode Active Material Evaluation) < Electrode Positive Fabrication >
    [00155] A slurry was prepared by mixing the Na4Mn3(PO4)2P2O7 (positive electrode active material) obtained in Example 2, carbon (conductive additive) and PVdF (binder) in the weight ratio 75 : 20 : 5, then dispersing The mixture is added to N-methyl-2-pyrrolidone (dispersant).
    [00156] This slurry was coated in aluminum foil (current collector), dried and laminated, thus producing a positive electrode constituted, as successive layers, of the current collector and the active material layer of the positive electrode. <Test Cell Manufacturing>
    [00157] With the exception of using DEC instead of DMC, a coin-type test cell was manufactured in the same manner as in Example 1. <Evaluation Method>
    [00158] Ten charge discharge cycles were performed under the following conditions in the test cell described above, and the charge discharge characteristics were evaluated. The relationship between energy density and potential in the first cycle and the tenth cycle is shown in figure 8. • Potential range: 2.5 V to 4.1 V • Current density: 8.5 mA/g • Temperature : 25°C
    [00159] As shown in figure 8, even after ten cycles, loading and unloading are possible in the same potential region as in the first cycle. Furthermore, it was confirmed that the discharge energy density can also be retained (capacity retention, 96%; reversible capacity, 18 mAh/g). That is, it has been found that the positive electrode active material of Example 2 can be charged and discharged in a potential region where the electrolyte solution is stable, and the cycle performance is excellent. [Example 3] (Synthesis of Sodium Battery Positive Electrode Active Material)
    [00160] Na4P2O7 (compound containing Na and P), (CH3COO)2Co (compound containing Co) and NH4H2PO4 (compound containing P) were added, together with glycolic acid (gelling agent), to an acidic solution (aqueous solution of nitric acid ) in a molar ratio of Na : Co : P = 4 : 3 : 4 and dissolved, and the solution was stirred at 80°C. The resulting gel was burnt in an open air atmosphere at 700°C for 15 hours.
    [00161] The crystal structure of the synthesized material obtained by burning was analyzed with an XRD. The results are shown in figure 9. From figure 9, it was confirmed that the resulting synthesized material is Na4Co3(PO4)2P2O7. It was confirmed that the synthesized material (Na4Co3(PO4)2P2O7) has a crystal structure that belongs to the Pn21a space group shown in figures 1 to 3. (Evaluation of Positive Electrode Material of Sodium Battery) <Positive Electrode Fabrication>
    [00162] A slurry was prepared by mixing the Na4Co3(PO4)2P2O7 (positive electrode active material) obtained in Example 3, carbon (conductive additive) and PVdF (binder) in the weight ratio 75 : 20 : 5, then to disperse the mixture in N-methyl-2-pyrrolidone (dispersant).
    [00163] This slurry was coated on an aluminum sheet (current collector), dried and laminated, thus producing a positive electrode constituted, as successive layers, of the current collector and the active material layer of the positive electrode. <Test Cell Manufacturing>
    [00164] A coin-type test cell was manufactured in the same manner as in Example 2. <Assessment Method>
    [00165] Fifty charge discharge cycles were performed under the following conditions in the test cell described above, and the charge discharge characteristics were evaluated. The relationships between energy density and potential in the first cycle and the fiftieth cycle are shown in figure 10. Furthermore, the number of cycles versus charge energy density and discharge energy density is shown in figure 11. • Potential range: 3.0 V to 4.7 V • Current density: 17 mA/g • Temperature: 25°C
    [00166] Also, the load unloading cycle of the above test cell was performed under the following conditions, and the load unloading characteristics were evaluated. The charge curve and discharge curve at the tenth cycle are shown in figure 12. Potential range: 3.0 V to 4.8 V • Current density: 1700 mA/g • Temperature: 25°C
    [00167] As shown in figure 10, even after fifty cycles, charging and discharging are possible in the same potential region as in the first cycle. Also, compared to Examples 1 and 2, an increase in reversible capacity was confirmed. Furthermore, as shown in Figure 11, it was confirmed that even after fifty cycles, the energy density can be retained. That is, the positive electrode active material of Example 3 was found to have a high reversible capacity (about 90 mAh/g) in the potential region where the electrolyte solution is stable, and in addition to have excellent cycle performance . As shown in figure 12, even at the very high current density of 1700 mAh/g, a reversible capacity of about 82 mAh/g was displayed. That is, assuming the reduction in capacity is small despite the fact that the current density becomes 100 times greater than in the charge discharge cycle test above at a current density of 17 mA/g, the active electrode material positive of Example 3 can be referred to as a beneficial material to obtain a superior battery input and output. [Examples 4 to 8] (Synthesis of Positive Electrode Materials of Sodium Batteries)
    [00168] Na4P2O7 (compound containing Na and P), (CH3COO)2Co (compound containing Co), (CH3COO)2Mn (compound containing Mn) and NH4H2PO4 (compound containing P) were added, along with glycolic acid (gelling agent), to an acidic solution (aqueous solution of nitric acid) in loading amounts shown in Table 1 to obtain the molar ratios of Na, Co, Mn and P shown in Table 1 and dissolved, and the solutions were stirred at 80°C. The resulting gels were burned in an open air atmosphere at 700°C for 15 hours. [Table 1] Table 1

    [00169] The crystal structures of the synthesized materials obtained by burning in Examples 4 to 8 were analyzed with an XRD. The results are shown in Table 2.
    [00170] It was confirmed that the synthesized materials obtained in Examples 4 to 8 are, respectively, Na4Co3(PO4)2P2O7 (Example 4), Na4Co2.7Mn0.3(PO4)2P2O7 (Example 5), Na4Co2.4Mn0.6(PO4 )2P2O7 (Example 6), Na4Co2,2Mn0.8(PO4)2P2O7 (Example 7) and Na4Co2.1Mn0.9(PO4)2P2O7 (Example 8). Also, it was confirmed that the synthesized materials obtained in Examples 4 to 8 have crystal structures that belong to the Pn21a space group shown in figures 1 to 3. [Table 2] Table 2
    (Evaluation of Positive Electrode Materials of Sodium Batteries) <Manufacture of Positive Electrodes>
    [00171] The slurries were prepared by mixing the electrode positive active materials obtained in Examples 4 to 8 above (Na4Co3.0(PO4)2P2O7 (Example 4), Na4Co2.7Mn0.3(PO4)2P2O7 (Example 5), Na4Co2.4Mn0.6(PO4)2P2O7 (Example 6), Na4Co2.2Mn0.8(PO4)2P2O7 (Example 7), Na4Co2.1Mn0.9(PO4)2P2O7 (Example 8)) with carbon (conductive additive) and PVdF (binder) in the weight ratio 75 (positive electrode active material) : 20 (conductive additive) : 5 (binder), then dispersing the mixture in N-methyl-2-pyrrolidone (dispersant).
    [00172] These slurries were coated in aluminum foil (current collector), dried and laminated, thus producing positive electrodes constituted, as successive layers, of the current collector and the active material layer of positive electrode. <Test Cell Manufacturing>
    [00173] Coin-type test cells were manufactured in the same manner as in Example 2 using the positive electrodes described above containing the positive electrode active materials of Examples 4 to 8. <Assessment Method>
    [00174] Three charge discharge cycles were performed in the above test cells under the following conditions, and the charge discharge characteristics were evaluated. • Potential Range: Example 4; 3.0V to 4.7V, Examples 5 to 8; 3.0 V to 4.8 V • Current density: 17 mA/g • Temperature: 25°C
    [00175] Figure 13 shows the relationship between energy density and potential in the third cycle (discharge curve and charge curve). In Figure 13, (a) shows the results of Example 4, (b) shows the results of Example 5, (c) shows the results of Example 6, (d) shows the results of Example 7, and (e) shows the results from Example 8.
    [00176] Figure 14 shows the discharge curves in the third cycle of Examples 4 to 8. In figure 14, (a) to (e) correspond to (a) to (e) in figure 13.
    [00177] Figure 15 shows the cycle performances (number of cycles versus discharge energy density) of Examples 4 to 8.
    [00178] As shown in Figures 13 and 14, all Examples 4 to 8 exhibited excellent discharge capacities of 90 to 103 mAh/g in the high potential region of 3.0 to 4.8 V.
    [00179] In particular, in Examples 5 to 7 where the Co2+ sites of Na4Co3.0(PO4)2P2O7 were replaced by Mn2+ in a ratio of 0.3 <a <0.8 in the general formula Na4Co(3-a)Mna (PO4)2(P2O7), improvements were observed in capacity performance and voltage characteristics compared to Example 4 (Na4Co3.0(PO4)2P2O7). This is believed to be largely due to the fact that, in cases where the replacement ratio of Co2+ by Mn2+ is in the above range (0.3 <a <0.8), the Mn2+ is replaced by having the charge compensated not only for Mn2+/3+, but even for Mn3+/4+ in the 4.7V potential region and above.
    [00180] Furthermore, in Example 8 where, in the general formula Na4Co(3-a)Mna(PO4)2(P2O7), Co2+ was replaced by Mn2+ in the ratio a = 0.9, it is conceivable that due to the fact that the conductivity positive electrode active material electronics is reduced due to Mn2+, the battery resistance increases and, compared to Example 4 (Na4Co3.0(PO4)2P2O7), the capacity performance and voltage characteristics have decreased.
    [00181] Also, as shown in figure 15, all Examples 4 to 8 maintained a high capacity of about 85 to 103 mAh/g over three cycles, furthermore, it was confirmed that the cycle performances were satisfactory.
    [00182] Furthermore, contrasting the results of Example 3 with the results of Example 2, it was found that, compared to an electrode positive active material where M = Co, an electrode positive active material where M = Mn has a lower capacity performance and a low labor potential. This explains the general finding that replacing a part of Co with Mn will result in a decline in performance. So, the fact that the substitution of Co2+ for Mn2+ in the ratio of 0.3 <a <0.8 within the general formula Na4Co(3-a)Mna(PO4)2(P2O7) as in Examples 5 to 7 above, the Capacity performance and work potential can be improved is an unforeseen effect. [Examples 9 to 12] (Synthesis of Positive Electrode Materials of Sodium Batteries)
    [00183] Na2P2O7 (compound containing Na and P), (CH3COO)2Co (compound containing Co), (CH3COO)2Mn (compound containing Mn), (CH3COO)2Ni (compound containing Ni) and NH4H2PO4 (compound containing P) were added , together with glycolic acid (gelling agent), to an acidic solution (aqueous solution of nitric acid) in loading amounts shown in Table 3 to obtain the molar ratios of Na, Co, Mn, Ni and P shown in Table 3 and dissolved , and the solutions were stirred at 80°C. The resulting gels were burned in an open air atmosphere at 700°C for 15 hours. [Table 3] Table 3


    [00184] The crystal structures of the synthesized materials obtained by burning in Examples 9 to 12 were analyzed with an XRD. The results are shown in Table 4.
    [00185] It was confirmed that the synthesized materials obtained in Examples 9 to 12 are, respectively, Na4Co3(PO4)2P2O7 (Example 9), Na4Co2.4Mn0.3Ni0.3(PO4)2P2O7 (Example 10), Na4Co1.0Mn1.0Ni1 ,0(PO4)2P2O7 (Example 11) and Na4Co0.6Mn1,2Ni1,2(PO4)2P2O7 (Example 12). Also, it was confirmed that the synthesized materials obtained in Examples 9 to 12 have crystal structures belonging to the Pn21a space group, shown in figures 1 to 3. [Table 4] Table 4
    (Evaluation of Positive Electrode Materials for Sodium Batteries) <Production of Positive Electrodes>
    [00186] The slurries were prepared by mixing the electrode positive active materials obtained in Examples 9 to 12 above (Na4Co3.0(PO4)2P2O7 (Example 9), Na4Co2.4Mn0.3Ni0.3(PO4)2P2O7 (Example 10 ), Na4Co1.0Mn1.0Ni1.0(PO4)2P2O7 (Example 11), Na4Cθo,6Mni,2Mii,2(Pθ4)2P2θ7 (Example 12)) with carbon (conductive additive) and PVdF (binder) in the weight ratio 75 (positive electrode active material) : 20 (conductive additive) : 5 (binder), then dispersing the mixture in N-methyl-2-pyrrolidone (dispersant).
    [00187] These slurries were coated in aluminum foil (current collector), dried and laminated, thus producing positive electrodes constituted, as successive layers, of the current collector and the active material layer of positive electrode. <Test Cell Manufacturing>
    [00188] Coin-type test cells were manufactured in the same manner as in Example 2 using the positive electrodes described above which contain the positive electrode active materials of Examples 9 to 12. <Assessment Method>
    [00189] Three charge discharge cycles were performed in the above test cells under the following conditions, and the charge discharge characteristics were evaluated. • Potential range: Example 9; 3.0V to 4.7V, Examples 10 to 12; 3.0 V to 4.8 V • Current density: 17 mA/g • Temperature: 25°C
    [00190] Figure 16 shows the relationship between energy density and potential in the third cycle (discharge curve and charge curve). In Figure 16, (a) shows the results of Example 9, (b) shows the results of Example 10, (c) shows the results of Example 11, and (d) shows the results of Example 12.
    [00191] As shown in Figure 16, all Examples 9 to 11 exhibited excellent discharge capacities of 90 to 95 mAh/g in the high potential region of 3.0 to 4.8 V. Example 12 shows a discharge capacity of 35 mAh/g in the high potential region of 3.0 to 4.8 V.
    [00192] In particular, in Examples 10 and 11 where the Co2+ sites of Na4Co3.0(PO4)2P2O7 were replaced by Mn2+ and Ni2+ in ratios of 0.3 <b < 1.0 and 0.3 <c < 1, 0 in the general formula Na4Cθ(3-b-c)MnbNic(PO4)2(P2O7), improvements were observed in capacity performance and voltage characteristics compared to Example 9 (Na4Co3,0(PO4)2P2O7). This apparently occurs, in cases where the replacement ratios of Co2+ by Mn2+ and Ni2+ are in the above ranges (0.3 <b <1.0, 0.3 <c <1.0), the substituted Mn2+ may have the charge compensated not only for Mn2+/3+, but even for Mn3+/4+ in the potential region of 4.7 V and above, and the substituted Ni2+ becomes Mo3+ at a high potential, so that the charge compensation of Ni2+/3+ proceed at a high potential.
    [00193] In Example 8 where, in the general formula Na4Co(3-a)Mna(PO4)2(P2O7), Co2+ was replaced by Mn2+ in the ratio a (the ratio of Mn) = 0.9, it decreases in capacity performance and voltage characteristics were observed compared to Examples 5 to 7. By contrast, when replacing a portion of Co with Ni in addition to Mn, even when b (the ratio of Mn) = 1.0 as in Example 11, improvements in capacity performance and voltage characteristics were confirmed. From these results, although it is believed that the replacement of Co2+ by Mn2+ causes a reduction in the electronic conductivity of the active material, it can be assumed that, when replacing Co2+ by Mn2+ and also by Ni2+, it has a relatively high electronic conductivity, the reduction in the electronic conductivity of the active material due to Mn2+ can be suppressed.
    [00194] Also, contrasting the results of Example 3 with the results of Examples 1 and 2, it is visible that the positive electrode active materials where M = Ni and the positive electrode active materials where M = Mn have capacity performances lower than those of electrode positive active materials where M = Co. Above all, that is why it is commonly believed that replacing a part of Co with Mn or Ni will result in a decline in performance. So, the fact that when replacing Co2+ by Mn2+ and Ni2+ in the ratios of 0.3 <b < 1.0 and 0.3 <c < 1.0 within the general formula Na4Co(3-bc)MnbNic(PO4)2 (P2O7) As in Examples 10 and 11 above, capacity performance and work potential can be improved is an unforeseen effect. 1: Negative electrode 2: Positive electrode 3: Electrolytic layer 4: Negative electrode active material layer 5: Negative electrode current collector 6: Positive electrode active material layer 7: Positive electrode current collector 8: Secondary battery sodium
    权利要求:
    Claims (7)
    [0001]
    1. Positive electrode active material of a sodium battery (8), characterized in that it is represented by the general formula (1) or general formula (2) below:
    [0002]
    2. Positive electrode active material of a sodium battery (8), characterized in that it is represented by the general formula (1) or general formula (2) below:
    [0003]
    3. Positive electrode active material, according to claim 1, characterized in that it has the formula
    [0004]
    4. Positive electrode active material according to claim 1, characterized in that it has the formula
    [0005]
    5. Positive electrode active material, according to claim 1, characterized in that it has the formula
    [0006]
    6. Method of producing the positive electrode active material of a sodium battery (8), as defined in claim 1, characterized in that it comprises: a pre-burning step of burning a mixture of starting material that includes by the minus one Na-containing compound, a Co-containing compound, a Mn-containing compound, and a P-containing compound in an open-air atmosphere at a temperature of 150 to 500 °C; and a main firing step of burning the pre-burned material thus obtained in an open-air atmosphere at a temperature of 500 to 800 °C after implementing the pre-burning step.
    [0007]
    7. Method of production of the active material of positive electrode of a sodium battery (8), according to claim 6, characterized in that it additionally comprises, before the pre-burning step, a step of size reduction of the Na-containing compound, Co-containing compound, Mn-containing compound and P-containing compound.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112014004630B1|2021-04-20|positive electrode active material for sodium battery and method of manufacturing this
    Zhang et al.2016|P2–Na2/3Ni1/3Mn5/9Al1/9O2 microparticles as superior cathode material for sodium-ion batteries: enhanced properties and mechanism via graphene connection
    Pramudita et al.2017|An initial review of the status of electrode materials for potassium‐ion batteries
    Chen et al.2019|Achieving High Energy Density through Increasing the Output Voltage: A Highly Reversible 5.3 áV Battery
    Huie et al.2015|Cathode materials for magnesium and magnesium-ion based batteries
    Liu et al.2019|Layered vanadium oxides with proton and zinc ion insertion for zinc ion batteries
    Yi et al.2012|High rate micron-sized niobium-doped LiMn1. 5Ni0. 5O4 as ultra high power positive-electrode material for lithium-ion batteries
    Xu et al.2013|Synthesis of Co3O4 nano-octahedra enclosed by {111} facets and their excellent lithium storage properties as anode material of lithium ion batteries
    Sharma et al.2007|Lithium recycling behaviour of nano-phase-CuCo2O4 as anode for lithium-ion batteries
    Karthikeyan et al.2012|Electrochemical performance of cobalt free, Li1. 2 | O2 cathodes for lithium batteries
    Choi et al.2010|Li-ion batteries from LiFePO4 cathode and anatase/graphene composite anode for stationary energy storage
    Hwang et al.2016|Effect of nickel and iron on structural and electrochemical properties of O3 type layer cathode materials for sodium-ion batteries
    EP2919304B1|2017-01-11|Positive electrode active material and hybrid ion battery
    Li et al.2018|Co-modification by LiAlO2-coating and Al-doping for LiNi0. 5Co0. 2Mn0. 3O2 as a high-performance cathode material for lithium-ion batteries with a high cutoff voltage
    Palanisamy et al.2017|Insights into the dual-electrode characteristics of layered Na0. 5Ni0. 25Mn0. 75O2 materials for sodium-ion batteries
    Pang et al.2019|P2-type Na2/3Mn1/2Co1/3Cu1/6O2 as advanced cathode material for sodium-ion batteries: electrochemical properties and electrode kinetics
    Hameed et al.2014|Carbon coated Li3V2 | 3 from the single-source precursor, Li2 | 2 | 2 |· 6H2O as cathode and anode materials for Lithium ion batteries
    Li et al.2020|High-voltage non-aqueous Zn/K1. 6Mn1. 2Fe | 6 batteries with zero capacity loss in extremely long working duration
    US20160006028A1|2016-01-07|Method of preparing a vanadium oxide compound and use thereof in electrochemical cells
    JP5699876B2|2015-04-15|Sodium ion battery active material and sodium ion battery
    Zhang et al.2017|A novel conversion anode composite for lithium ion batteries based on MnF2/carbon nanotubes with hierarchical structure
    Kong et al.2018|Graphite modified AlNbO4 with enhanced lithium—Ion storage behaviors and its electrochemical mechanism
    He et al.2006|Synthesis and electrochemical properties of chemically substituted LiMn2O4 prepared by a solution-based gel method
    Meng et al.2021|O3-NaNi0. 47Zn0. 03Mn0. 5O2 cathode material for durable Na-ion batteries
    CN105684198A|2016-06-15|Positive electrode active material for sodium batteries, and sodium battery
    同族专利:
    公开号 | 公开日
    KR20140041911A|2014-04-04|
    EP2752925A4|2015-08-12|
    EP2752925A1|2014-07-09|
    BR112014004630A2|2017-03-14|
    CN103765640A|2014-04-30|
    WO2013031331A1|2013-03-07|
    CN103765640B|2016-11-23|
    US9660253B2|2017-05-23|
    CA2846472C|2016-08-16|
    EP2752925B1|2019-01-16|
    CA2846472A1|2013-03-07|
    AU2012303284B2|2015-07-23|
    AU2012303284A1|2014-03-13|
    JPWO2013031331A1|2015-03-23|
    KR101795845B1|2017-11-08|
    KR101691774B1|2016-12-30|
    KR20160025630A|2016-03-08|
    US20140197358A1|2014-07-17|
    JP5673836B2|2015-02-18|
    RU2014106754A|2015-10-10|
    RU2566085C1|2015-10-20|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    BG39778A1|1984-10-30|1986-08-15|Mohhev|
    US6068949A|1995-04-13|2000-05-30|Rentech, Inc.|Alkali metal ion battery electrode material|
    US6200704B1|1998-09-01|2001-03-13|Polyplus Battery Company, Inc.|High capacity/high discharge rate rechargeable positive electrode|
    KR100814540B1|2001-04-06|2008-03-17|발렌스 테크놀로지, 인코포레이티드|Sodium Ion Batteries|
    JP4170733B2|2002-11-07|2008-10-22|Ａｇｃセイミケミカル株式会社|Cathode active material for non-aqueous electrolyte secondary battery|
    US7348100B2|2003-10-21|2008-03-25|Valence Technology, Inc.|Product and method for the processing of precursors for lithium phosphate active materials|
    FR2864348B1|2003-12-18|2006-03-10|Commissariat Energie Atomique|LITHIUM ACCUMULATOR HAVING BOTH ELECTRICAL POTENTIAL AND HIGH LTHIUM INSERTION CAPABILITY.|
    CN100336247C|2004-03-30|2007-09-05|中国科学院物理研究所|Method for preparing phosphate positive-pole material of lithium-ion cell|
    CN1630126A|2004-10-11|2005-06-22|湘潭大学|sodium ion battery and method for manufacturing the same|
    JP2008130265A|2006-11-17|2008-06-05|Kyushu Univ|Surface coated metal fluoride electrode active material|
    KR101159085B1|2006-11-17|2012-06-22|고쿠리쓰다이가쿠호진 규슈다이가쿠|Cathode active material for nonaqueous electrolyte secondary battery and method of producing cathode active material for nonaqueous electrolyte secondary battery|
    US20080213674A1|2007-02-24|2008-09-04|Ngk Insulators, Ltd.|Secondary battery|
    JP2008260666A|2007-04-13|2008-10-30|Kyushu Univ|Active material for sodium secondary battery, and method for producing the same|
    JP4595987B2|2007-10-25|2010-12-08|トヨタ自動車株式会社|Cathode active material|
    JP5418803B2|2008-07-02|2014-02-19|国立大学法人九州大学|All solid battery|
    JP5460979B2|2008-07-09|2014-04-02|住友化学株式会社|Transition metal phosphate, positive electrode for sodium secondary battery using the same, and secondary battery using the positive electrode|
    US8795889B2|2008-07-09|2014-08-05|Sumitomo Chemical Company, Limited|Transition metal phosphate, production process thereof, positive electrode, and sodium secondary battery|
    JP5359442B2|2009-03-25|2013-12-04|住友化学株式会社|Sodium ion battery|
    JP5540281B2|2009-05-01|2014-07-02|国立大学法人九州大学|Method for producing positive electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using the same|
    JP2011054562A|2009-08-04|2011-03-17|Sumitomo Chemical Co Ltd|Determination method of alkali metal-doped transition metal oxides|
    WO2011038499A1|2009-10-02|2011-04-07|Linda Faye Nazar|Sodium metal phosphate olivines for sodium-ion batteries|
    US20120199785A1|2009-10-08|2012-08-09|Sumitomo Chemical Company, Limited|Transition metal phosphate, and sodium secondary battery|
    US8900746B2|2009-10-13|2014-12-02|Kabushiki Kaisha Toyota Chuo Kenkyusho|Aqueous secondary battery|
    JP5707698B2|2009-12-24|2015-04-30|住友化学株式会社|Electrode manufacturing method, electrode paste manufacturing method, and sodium secondary battery|
    RU2566085C1|2011-08-29|2015-10-20|Тойота Дзидося Кабусики Кайся|Active material for sodium accumulator positive electrode and method of its manufacturing|
    GB2495279A|2011-09-30|2013-04-10|Faradion Ltd|A condensed polyanion electrode material|
    CN102509789A|2011-10-17|2012-06-20|中南大学|Method for preparing positive material fluorine-doped sodium vanadium phosphate of sodium-containing lithium ion battery|
    WO2013187160A1|2012-06-12|2013-12-19|トヨタ自動車株式会社|Positive electrode material for sodium batteries and method for producing same|
    JP5527385B2|2012-11-08|2014-06-18|トヨタ自動車株式会社|Cathode active material and hybrid ion battery|RU2566085C1|2011-08-29|2015-10-20|Тойота Дзидося Кабусики Кайся|Active material for sodium accumulator positive electrode and method of its manufacturing|
    WO2013035222A1|2011-09-09|2013-03-14|株式会社日立製作所|Secondary battery positive electrode material and secondary battery using same|
    GB2495279A|2011-09-30|2013-04-10|Faradion Ltd|A condensed polyanion electrode material|
    WO2013187160A1|2012-06-12|2013-12-19|トヨタ自動車株式会社|Positive electrode material for sodium batteries and method for producing same|
    JP5527385B2|2012-11-08|2014-06-18|トヨタ自動車株式会社|Cathode active material and hybrid ion battery|
    KR101546877B1|2013-06-12|2015-08-25|한국과학기술원|Material for cathode of sodium ion battery and manufacturing method for the same, and sodium ion battery comprising the same|
    JP2015018621A|2013-07-09|2015-01-29|トヨタ自動車株式会社|Sodium battery cathode active material and method of producing the same|
    JP2015026483A|2013-07-25|2015-02-05|トヨタ自動車株式会社|Positive electrode for sodium batteries, and sodium battery|
    US10026520B2|2013-08-16|2018-07-17|Sk Innovation Co., Ltd.|Positive electrode active material for secondary battery|
    US9716274B2|2013-10-24|2017-07-25|Toyota Jidosha Kabushiki Kaisha|Cathode active material for sodium batteries, and sodium battery|
    JP6384661B2|2014-08-25|2018-09-05|日本電気硝子株式会社|Positive electrode active material for sodium ion secondary battery and method for producing the same|
    JP2016085887A|2014-10-27|2016-05-19|トヨタ自動車株式会社|Sodium ion secondary battery|
    JP2016085890A|2014-10-27|2016-05-19|トヨタ自動車株式会社|Sodium ion secondary battery|
    JP2016085888A|2014-10-27|2016-05-19|トヨタ自動車株式会社|Sodium ion secondary battery|
    US20180183044A1|2015-10-28|2018-06-28|Nippon Electric Glass Co., Ltd.|Positive electrode active material for sodium-ion secondary cell|
    CN105702931A|2016-03-22|2016-06-22|陈波|Application of reduced graphene oxide-TiO2-Cr2O3 composite material in sodium-ion battery|
    JP6566137B2|2016-06-30|2019-08-28|富士通株式会社|Positive electrode material for secondary battery, method for producing the same, and lithium ion secondary battery|
    RU2642425C1|2016-11-15|2018-01-25|Общество с ограниченной ответственностью "Общество с ограниченной ответственностью "Литиевые нанотехнологии для энергетики"|METHOD OF SYNTHESIS OF ACTIVE COMPONENT OF CATHODE MASS BASED ON LiFePO4 AND CATHODE MASS, CONTAINING ACTIVE COMPONENT|
    CN110521035A|2017-03-29|2019-11-29|住友化学株式会社|The manufacturing method of sodium rechargeable battery electrode active material, sodium rechargeable battery electrode, sodium rechargeable battery and metal composite oxide|
    CN110546796A|2017-04-27|2019-12-06|日本电气硝子株式会社|Positive electrode active material for sodium ion secondary battery|
    CN107017395B|2017-05-22|2020-04-21|中南大学|Carbon-coated sodium manganese pyrophosphate @ reduced graphene oxide composite material with sandwich structure and preparation method and application thereof|
    CN107017398B|2017-06-01|2019-06-11|中南大学|A kind of pyrophosphoric acid vanadium sodium/carbon composite anode material, preparation and its application|
    WO2019003903A1|2017-06-27|2019-01-03|日本電気硝子株式会社|Positive electrode active material for sodium-ion secondary battery|
    JP6988584B2|2018-03-06|2022-01-05|トヨタ自動車株式会社|Manufacturing method of positive electrode, non-aqueous electrolyte secondary battery, and positive electrode|
    JP2020047587A|2018-09-14|2020-03-26|トヨタ自動車株式会社|Secondary battery system and method of estimating internal state of secondary battery|
    RU2718878C1|2019-03-28|2020-04-15|Федеральное государственное бюджетное образовательное учреждение высшего образования "Московский государственный университет имени М.В. Ломоносова" |Connection for electrode material of metal-ion batteries, electrode material based on it, electrode and battery based on electrode material|
    CN110299528B|2019-07-02|2020-12-25|中南大学|Fluorinated phosphate ferric sodium pyrophosphate @ C @ RGO composite material, preparation method thereof and application thereof in sodium ion battery|
    CN111224085A|2020-01-14|2020-06-02|中南大学|Nitrogen-doped carbon-coated chromium manganese phosphate sodium @ mesoporous carbon composite material, preparation method thereof and application thereof in sodium ion battery|
    CN111261870B|2020-01-29|2021-10-29|桂林理工大学|NASICON structure Na4CrMn3Method for producing materials and use thereof|
    CN111446429B|2020-03-27|2021-12-21|珠海冠宇电池股份有限公司|Poly-polyanion cathode material and preparation method and application thereof|
    法律状态:
    2018-04-03| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-10-08| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-03-09| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-04-20| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 13/06/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2011-186131|2011-08-29|
    JP2011186131|2011-08-29|
    PCT/JP2012/065096|WO2013031331A1|2011-08-29|2012-06-13|Positive electrode active material for sodium batteries and method for producing same|
    [返回顶部]