Electrode active material for alkali metal batteries, electrodes containing the same, and alkali metal batteries

Abstract

The present invention addresses the problem of providing an electrode active material which has long charge / discharge lifespan, and can provide a high-capacity alkali metal battery. The problem is solved by means of an electrode active material which is for an alkali metal battery, and is characterized by being represented by formula: Aa1MSa2Xa3 (in the formula, A is selected from among Li and Na, M is selected from among group 4-6 elements (V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W), X is selected from among F, Cl, Br, I, CO3, SO4, NO3, BH4, BF4, PF6, ClO4, CF3SO3, (CF3SO2)2N, (C2F5SO2)2N, (FSO2)2N, and [B(C2O4)2], a1 is 1-9, a2 is 2-6, a3 is 3, and when a3 is 0, a2 is not 4. In addition, when M does not include V, a3>0).

Description

[Technical field]

[0001] The present invention relates to an electrode active material for an alkali metal battery, an electrode containing the same, and an alkali metal battery. More specifically, the present invention relates to an electrode active material capable of providing an alkali metal battery having a long charge / discharge life and a high capacity, an electrode containing the same, and an alkali metal battery having a long charge / discharge life and a high capacity. [Background technology]

[0002] 2. Description of the Related Art In recent years, there has been an increasing demand for lithium ion batteries for storing electric power in automobiles such as electric vehicles and hybrid vehicles, and in power generation devices such as solar cells and wind power generators. Moreover, from the perspective of ensuring safety, all-solid-state batteries that do not use liquid in the electrolyte layer but use solid electrolytes are being actively researched. Here, a lithium ion battery or an all-solid-state battery is composed of a laminate of a positive electrode, an electrolyte layer, and a negative electrode. Among these, as a positive electrode active material contained in the positive electrode active material of an all-solid-state battery, for example, in International Publication WO2016 / 063877 (Patent Document 1), 2 S AX (wherein A is an alkali metal and X is I, Br, Cl, F, BF 4 , B.H. 4 , S.O. 4 , B.O. 3 , P.O. 4 , O, Se, N, P, As, Sb, PF 6 , AsF 6 , ClO 4 , NO 3 , CO 3 , C.F. 3 SO 3 , C.F. 3 COO, N(SO 2 F) 2 and N(CF 3 SO 2 ) 2 A positive electrode active material for an all-solid-state secondary battery represented by the formula (1) is proposed.

[0003] The above-mentioned positive electrode active material has low conductivity, so it is necessary to mix it with a solid electrolyte or a conductive additive. Although mixing improves conductivity, there is an issue that the amount of positive electrode active material in the positive electrode is reduced, resulting in a decrease in capacity. In order to solve the above problems, a positive electrode active material that exhibits sufficient conductivity without being mixed with a solid electrolyte or a conductive additive has been proposed by Hayashi, Tatsumisago et al., Annual Meeting of the Chemical Society of Japan (2017) (Non-Patent Document 1). 2 S.V. 2 S 3 -S(Li 3 VS 4 It has been reported that by using this positive electrode active material, charging and discharging is possible without mixing it with a solid electrolyte or conductive additive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2016 / 063877 [Non-Patent Document 1] Hayashi, Tatsumisako et al., Annual Meeting of the Chemical Society of Japan (2017) Summary of the Invention [Problem to be solved by the invention]

[0005] Non-Patent Document 1 describes the charge / discharge curve shown in Figure 1. As can be seen from Figure 1, the capacity decreases with each cycle. Therefore, even this positive electrode active material does not have sufficient charge / discharge life and capacity, and it has been desired to provide an electrode active material that can provide an alkali metal battery with a longer charge / discharge life and a higher capacity. [Means for solving the problem]

[0006] Based on the concept that ionic conductivity and electronic conductivity can be improved by imparting the role of an electrolyte to an active material, the inventors of the present invention discovered that an alkali metal battery with a longer charge / discharge life and a higher capacity can be provided by further incorporating a specific transition metal and an anion component as constituent components in an electrode active material containing sulfur as a constituent component, and thus arrived at the present invention. Thus, according to the present invention, there is provided a compound of the formula: A a1 MS a2 X a3 (In the formula, A is selected from Li and Na, M is selected from V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W, which are group 4 to 6 elements, and X is F, Cl, Br, I, CO 3 , S.O. 3 , S.O. 4 , NO 3 , B.H. 4 , B.F. 4 , P.F. 6 , ClO 4 , C.F. 3 SO 3 , (CF 3 SO 2 ) 2 N, (C 2 F 5 SO 2 ) 2 N, (FSO 2 ) 2 N and [B(C 2 O 4 ) 2 a1 is 1 to 9, a2 is 2 to 6, and a3 is 0 to 1; (when a1 is 3 and a3 is 0, a2 is not 4. Furthermore, when M does not contain V, a3>0). The present invention also provides an electrode for an alkali metal battery, which contains the above electrode active material. Further, according to the present invention, there is provided an alkali metal battery comprising a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode, wherein the electrodes, i.e., the positive electrode or the negative electrode, or both, contain the above-mentioned electrode active material. Effect of the Invention

[0007] According to the present invention, it is possible to provide an electrode active material which can provide an alkali metal battery having a longer charge / discharge life and a higher capacity. Furthermore, when the electrode active material has any of the following configurations, it is possible to provide an alkali metal battery having a longer charge / discharge life or a higher capacity. (1) A is Li, M is V, and X is Cl, Br, I, or SO 4 is selected from. (2) Formula: A a1 MS a2 X a3 However, (Li 2 S) b1 -(V 2 S 3 ) b2 -(Li c X) b3 (b1 / b2 is 1 to 9, b3 / b2 is 0.1 to 1.5, and c is 1 to 2). (3) A is Na, M is V, and X is Cl, Br, I, or SO 4 is selected from. (4) The alkali metal battery is an all-solid-state battery. (5) The alkali metal battery comprises a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode, the electrodes not including a solid electrolyte. [Brief description of the drawings]

[0008] [Figure 1] This is a charge / discharge curve described in Non-Patent Document 1. [Diagram 2] 1 is an XRD pattern of the electrode active material of Example 1. [Diagram 3] 1 shows an initial charge / discharge curve of the all-solid-state battery of Example 1. [Figure 4A] This is a charge / discharge curve of an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 67:33. [Figure 4B] 1 shows charge / discharge curves of an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 70:30. [Figure 4C]1 shows charge / discharge curves of an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 75:25. [Figure 5A] This is a charge / discharge curve when charging / discharging is started from a charged state for an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 67:33. [Figure 5B] This is a charge / discharge curve when charging / discharging is started from a discharged state of an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 67:33. [Figure 6] 1 is an XRD pattern of the electrode active material of Example 2. [Figure 7A] 1 shows charge / discharge curves of an all-solid-state battery using an electrode made of an electrode active material containing Li2S:V2S3 in a molar ratio of 75:25. [Figure 7B] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiCl. [Figure 7C] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiBr. [Figure 7D] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.75Li2S 0.25V2S3) 10LiI. [Figure 7E] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10Li2SO4. [Figure 8A] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.75Li2S 0.25V2S3) 10LiI. [Figure 8B] 1 is a graph showing the change over the number of cycles of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiI. [Figure 9] This is a charge / discharge curve when the charge / discharge capacity of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiI is regulated. [Figure 10A]1 is a graph showing charge / discharge curves when charging / discharging was performed by changing the current density of an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiI. [Figure 10B] 1 is a graph showing the change in the number of cycles when charging and discharging an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiI at different current densities. [Figure 10C] 1 is a graph showing the change in the number of cycles when charging and discharging an all-solid-state battery using an electrode consisting of 90(0.75Li2S·0.25V2S3)·10LiI and a solid electrolyte of 54Li3PS4·46LiI at different current densities. [Figure 11A] Impedance plot of an all-solid-state battery using an electrode consisting of 90(0.75Li2S 0.25V2S3) 10LiI. [Figure 11B] Impedance plot of an all-solid-state battery using an electrode consisting of 90(0.75Li2S 0.25V2S3) 10LiI. [Figure 11C] Impedance plot of an all-solid-state battery using an electrode consisting of 90(0.75Li2S 0.25V2S3) 10LiI. [Figure 12A] 1 is an XPS plot showing the 2p orbital of S atoms in the electrode active material of Example 2. [Figure 12B] 1 is an XPS plot showing the 2p orbital of V atoms in the electrode active material of Example 2. [Figure 13] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.70Li2S 0.30V2S3) 10LiI. [Figure 14A] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90(0.70Li2S·0.30V2S3)·10Li2SO4. [Figure 14B] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 80(0.70Li2S 0.30V2S3) 10LiI 10Li2SO4. [Figure 15A] 1 is an XRD pattern of the electrode active material of Example 5. [Figure 15B] 1 is an XRD pattern of the electrode active material of Example 5. [Figure 16A] This is a charge / discharge curve of an all-solid-state battery using an electrode made of Li3VS4. [Figure 16B] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 90Li3VS4·10LiI. [Figure 16C] This is the charge / discharge curve of an all-solid-state battery using an electrode made of 90Li3VS4·10Li2SO4. [Figure 16D] This is the charge / discharge curve of an all-solid-state battery using an electrode consisting of 80Li3VS4·20Li2SO4. [Figure 17] 1 is an XRD pattern of the electrode active material of Example 6. [Figure 18] This is the charge / discharge capacity of an all-solid-state battery using an electrode made of 75Na2S·25V2S3. [Figure 19] This is the charge / discharge capacity of an all-solid-state battery using an electrode consisting of 90(0.75Na2S 0.25V2S3) 10NaI. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The electrode active material of the present invention relates to an active material contained in an electrode of an alkali metal battery. Here, the alkali metal battery is not particularly limited as long as it is a battery in which alkali metals such as Li and Na are exchanged between a positive electrode and a negative electrode as mobile ions during charging and discharging. For example, ion batteries such as lithium ion batteries and sodium ion batteries in which the electrolyte layer contains a non-aqueous electrolyte, all-solid-state batteries such as all-solid-state lithium batteries and all-solid-state sodium batteries in which a solid electrolyte layer is used as the electrolyte layer, and the like can be mentioned. In addition, the alkali metal battery may be a primary battery or a secondary battery, but since the electrode active material of the present invention has the effect of extending the charge and discharge life, it is preferable that it is a secondary battery.

[0010] (electrode active material) The electrode active material has the following formula: A a1 MS a2 X a3 It is expressed as: In the formula, A is selected from Li and Na. From the viewpoint of further improving the capacity, A is preferably Li. M is selected from the group of transition metals V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W. From the viewpoint of further improving the capacity, M preferably contains V or Nb. X is F, Cl, Br, I, CO 3 , S.O. 3 , S.O. 4 , NO 3 , B.H. 4 , B.F. 4 , P.F. 6 , ClO 4 , C.F. 3 SO 3 , (CF 3 SO 2 ) 2 N, (C 2 F 5 SO 2 ) 2 N, (FSO 2 ) 2 N and [B(C 2 O 4 ) 2 From the viewpoint of further improving the capacity, X is selected from the group of anion components from Cl, Br, I and SO 4 It is preferably selected from:

[0011] a1 is 1 to 9, a2 is 2 to 6, and a3 is 0 to 1 (however, when a1 is 3 and a3 is 0, a2 is not 4. Furthermore, when M does not contain V, a3>0). a1, a2, and a3 are molar ratios whose range changes depending on the valences of M and X. The value of a1 also changes depending on charging and discharging. When a1 is less than 1, the initial charging capacity is small, and it becomes necessary to include Li in the negative electrode. When a1 is greater than 9, an inverse fluorite-type Li 2The material is mainly composed of S, and the electronic conductivity may decrease. If a2 is less than 2, the capacity due to the oxidation-reduction of sulfur cannot be obtained, and the capacity in the high potential region decreases. If a2 is greater than 6, the electronic conductivity may decrease. If a3 is greater than 1, the ionic conductivity can be improved, but the electronic conductivity and theoretical capacity decrease. a1 is preferably 2 to 4, a2 is preferably 3 to 5, and a3 is preferably greater than 0, and more preferably 0.05 to 0.6. In the formula, a1 may be any numerical range included in the range of 1 to 9, and may be, for example, a range represented by a combination of any upper and lower limit values ​​selected from the values ​​of 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, or 9.0. In the formula, a2 may be any numerical range included in the range of 2 to 6, and may be, for example, a range represented by a combination of any upper and lower limit values ​​selected from the values ​​of 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, or 6.0. In the formula, a3 may be any numerical range included in the range of 0 to 1, and may be a range represented by any combination of upper and lower limit values ​​selected from the values ​​of 0.01, 0.025, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 0.99, or 1.0.

[0012] In one embodiment, the electrode active material has the formula: A a1 MS a2 X a3 (In the formula, A is selected from Li and Na, M is selected from Group 4 to 6 elements (V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W), and X is F, Cl, Br, I, CO 3 , S.O. 4 , NO 3 , B.H. 4 , B.F. 4 , P.F.6 , ClO 4 , CF 3 SO 3 , (CF 3 SO 2 ) 2 N, (C 2 F 5 SO 2 ) 2 , (FSO 2 ) 2 N and [B(C 2 O 4 ) 2 , and may be represented by a1 being 1 to 9, a2 being 2 to 6, and 0 < a3 ≤ 1).

[0013] In another embodiment, a3 in the above formula is 0. That is, the electrode active material is represented by the following formula: A a1 MS a2 (wherein A is selected from Li and Na, M is selected from Group 4 to 6 elements (V, Nb, Ta, Ti, Zr, Hf, Cr, Mo, and W), a1 is 1 to 9, and a2 is 2 to 6).

[0014] A a1 MS a2 X a3 Among the electrode active materials represented by, it is more preferable that it is an electrode active material represented by (Li 2 S) b1 -(V 2 S 3 ) b2 -(Li c X) b3 . b1, b2, and b3 are molar ratios. c is a molar ratio that ranges from 1 to 2 and varies according to the valence of X. c can be any numerical range included in the range of 1 to 2. For example, it can be a range represented by any combination of upper and lower limit values selected from values such as 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0. It is preferable that b1 / b2 is from 1 to 9 and b3 / b2 is from 0.1 to 1.5. When b1 / b2 is less than 1, an increase in material cost may occur due to an increase in vanadium content. When b1 / b2 is greater than 9, the electronic conductivity may decrease. Also, when b1 / b2 is less than 1, the initial charge capacity decreases because the lithium content decreases. When b3 / b2 is less than 0.1, the addition effect of the Li c X component may not be fully obtained. When b3 / b2 is greater than 1.5, the theoretical capacity decreases. b1 / b2 can be any numerical range included in the range of 1 to 9, for example, a range represented by any combination of upper and lower limit values selected from values such as 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, or 9.0. b3 / b2 can be any numerical range included in the range of 0.1 to 1.5, for example, a range represented by any combination of upper and lower limit values selected from values such as 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5. From the viewpoint of the balance of electronic conductivity, ionic conductivity, initial charge capacity, reversible capacity, and charge-discharge life, it is preferable that b1 / b2 is from 1.5 to 4.5, more preferably from 2 to 4, and even more preferably from 2.5 to 3.5. Also, it is preferable that b3 / b2 is from 0.1 to 1.0, and more preferably from 0.15 to 0.8.

[0015] When A is Li in the electrode active material, the peak corresponding to Li near 28° in 2θ / ° of XRD (X-ray diffraction) using CuKα rays 2 is preferably shown to have a full width at half maximum of 0.1° or more. With this half-width, a more poorly crystalline electrode active material can be obtained.

[0016] The method for producing the electrode active material is not particularly limited as long as it is a method capable of compounding the raw materials. Examples of the raw materials include sulfides of alkali metals, sulfides of transition metals such as V, and mixtures of salts of alkali metals and anion components. As a method for forming a composite, mechanochemical treatment is preferred from the viewpoints that it is possible to synthesize a sample with a more non-stoichiometric composition and to obtain a sample with low crystallinity. The mechanochemical treatment is not particularly limited to the treatment equipment and treatment conditions as long as each component can be reacted or compounded uniformly. As the processing device, a ball mill can be used. A ball mill is preferable because it can provide a large mechanical energy. Among ball mills, a planetary ball mill is preferable because the pot rotates on its axis and the table revolves in the opposite direction to the axis of rotation, and therefore a high impact energy can be efficiently generated.

[0017] The treatment conditions can be appropriately set depending on the treatment device used. For example, when a ball mill is used, the higher the rotation speed and / or the longer the treatment time, the more uniformly the raw materials can be mixed. Specifically, when a planetary ball mill is used, the conditions include a rotation speed of 50 to 600 rpm, a treatment time of 0.1 to 100 hours, and 1 to 100 kWh / 1 kg of raw materials. In order to prevent the alkali metal salt of the raw material from reacting with water or oxygen, it is preferable to perform the treatment in an inert atmosphere (e.g., an argon atmosphere) using a glove box or the like, in an environment with a moisture concentration of 1000 ppm or less and an oxygen concentration of 1000 ppm or less. By the above-mentioned mechanochemical treatment, an electrode active material is obtained.

[0018] (electrode) The electrode may consist of only the electrode active material, or may be mixed with a binder, a conductive material, an electrolyte, etc. The electrode for an alkali metal battery of the present invention includes an electrode active material. The electrode active material of the present invention has sufficiently high ionic conductivity and electronic conductivity by itself. Therefore, the amount of solid electrolyte and conductive material contained in conventional electrodes can be reduced, or the solid electrolyte and conductive material do not need to be used. As a result, the ratio of the electrode active material in the electrode can be increased, so that an alkali metal battery with a higher capacity can be provided. The ratio of the electrode active material in the electrode is not particularly limited, but it is preferable that the electrode active material is contained as a main component. Here, containing as a main component means that the ratio of the electrode active material in the electrode is 50% by mass or more with respect to the total components constituting the electrode. The ratio of the electrode active material in the electrode is preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 97% by mass or more, more preferably 98% by mass or more, more preferably 99% by mass or more, and most preferably 100% by mass. However, the use of a solid electrolyte or a conductive material is not denied, and these may be used as necessary.

[0019] Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, polyvinyl acetate, polymethyl methacrylate, and polyethylene. The binder may be contained in an amount of 40 parts by weight or less, preferably 30 parts by weight or less, more preferably 20 parts by weight or less, more preferably 10 parts by weight or less, more preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and more preferably 1 part by weight or less, relative to 100 parts by weight of the electrode active material. Examples of conductive materials include natural graphite, artificial graphite, acetylene black, ketjen black, denka black, carbon black, and vapor grown carbon fiber (VGCF). The conductive material may be contained in an amount of 40 parts by weight or less, preferably 30 parts by weight or less, more preferably 20 parts by weight or less, more preferably 10 parts by weight or less, more preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and more preferably 1 part by weight or less, relative to 100 parts by weight of the electrode active material in the electrode. Examples of the solid electrolyte include the electrolytes used in the solid electrolyte layer described in the section on alkali metal batteries below. In addition to the electrode active material of the present invention, an electrode active material other than the electrode active material of the present invention may be added as necessary. When the electrode active material of the present invention is used as a positive electrode active material, the electrode active material other than the electrode active material of the present invention may be, for example, 4 Ti 5 O 12 , ACoO 2 , AMnO 2 , A.V.O. 2 , ACrO 2 , ANiO 2 , A 2 NiMn 3 O 8 , ANi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 , S., A. 2 S, FeS, TiS 2 , AFeO 2 , A 3 V 2 (PO 4 ) 3 , A.M.n 2 O 4 (A is Li or Na). The electrode active material is LiNbO 3 , NaNbO 3 , Al 2 O 3 The electrode active material of the present invention may be coated with a material such as Li, Na, In, Sn, Sb, etc., a Na alloy, graphite, hard carbon, Li, etc. The thickness of the coating may be uniform or may be uneven, but it is preferable that the thickness is uniform. When the electrode active material of the present invention is used as a negative electrode active material, examples of the electrode active material other than the electrode active material of the present invention include metals such as Li, Na, In, Sn, Sb, etc., Na alloys, graphite, hard carbon, Li 4 / 3 Ti 5 / 3 O 4, Li 3 V 2 (PO 4 ) 3 , Na 4 / 3 Ti 5 / 3 O 4 , Na 3 V 2 (PO 4 ) 3 , and various transition metal oxides such as SnO. The electrode active material other than the electrode active material of the present invention may be contained in an amount of 40 parts by weight or less, preferably 30 parts by weight or less, more preferably 20 parts by weight or less, more preferably 10 parts by weight or less, more preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and more preferably 1 part by weight or less, relative to 100 parts by weight of the electrode active material. The electrode can be obtained in the form of a pellet by, for example, mixing an electrode active material and, optionally, a binder, a conductive material, an electrolyte, and the like, and pressing the resulting mixture.

[0020] (Alkaline metal battery) The electrode used in the alkali metal battery is the electrode of the present invention. The electrode of the present invention can be used as a positive electrode, a negative electrode, or a positive electrode and a negative electrode (however, the compositions of the electrodes are different from each other). When the electrode of the present invention is used as a positive electrode, it is not particularly limited as long as an alkali metal such as Li or Na can be exchanged between a positive electrode and a negative electrode as a mobile ion during charging and discharging, and it may be used in combination with a negative electrode other than the negative electrode of the present invention. Also, when the electrode of the present invention is used as a negative electrode, it is not particularly limited as long as an alkali metal such as Li or Na can be exchanged between a positive electrode and a negative electrode as a mobile ion during charging and discharging, and it may be used in combination with a positive electrode other than the positive electrode of the present invention. Examples of the positive electrode active material used in the positive electrode other than the positive electrode of the present invention include A 4 Ti 5 O 12 , ACoO 2 , AMnO 2 , A.V.O. 2 , ACrO 2 , ANiO 2 , A 2NiMn 3 O 8 , ANi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 , S., A. 2 S, FeS, TiS 2 , AFeO 2 , A 3 V 2 (PO 4 ) 3 , A.M.n 2 O 4 (A is Li or Na). The positive electrode active material is LiNbO 3 , NaNbO 3 , Al 2 O 3 , NiS, etc. The thickness of the coating may be uniform or may vary, but it is preferably uniform. Examples of the negative electrode active material used in the negative electrode other than the negative electrode of the present invention include metals such as Li, Na, In, Sn, and Sb, Na alloys, graphite, hard carbon, and Li 4 / 3 Ti 5 / 3 O 4 , Li 3 V 2 (PO 4 ) 3 , Na 4 / 3 Ti 5 / 3 O 4 , Na 3 V 2 (PO 4 ) 3 , and various transition metal oxides such as SnO. The positive electrode and the negative electrode may be composed of only an electrode active material, or may be mixed with a binder, a conductive material, an electrolyte, etc. These negative electrode active materials or positive electrode active materials may be used alone or in combination of two or more kinds. The binder, conductive material and electrolyte may be any of those listed in the above section on electrodes. The electrode can be obtained in the form of a pellet by, for example, mixing an electrode active material and, optionally, a binder, a conductive material, an electrolyte, etc., and pressing the mixture obtained. In addition, when a metal sheet (foil) made of a metal or its alloy is used as the negative electrode active material, it can be used as it is.

[0021] The positive electrode and / or negative electrode may further be combined with a current collector to form a composite. The current collector can be combined with a positive electrode and / or a negative electrode, and the material, shape, etc. are not particularly limited as long as it can function as a current collector. The shape of the current collector may be a uniform alloy plate or a shape having holes. It may also be in the form of a foil, sheet, or film.

[0022] Examples of materials for the current collector include Ni, Cu, Ti, Fe, Co, Ge, Cr, Mo, W, Ru, Pd, Al, stainless steel, steel, etc. These materials may be used alone or in combination of two or more.

[0023] The electrolyte layer used in an alkali metal battery is made of different materials depending on whether the layer contains a nonaqueous electrolyte solution or is all-solid, in other words, whether it is a nonaqueous electrolyte layer or an all-solid electrolyte layer.

[0024] (1) Non-aqueous electrolyte layer The electrolyte layer can be composed of a mixture of a known electrolyte and a non-aqueous solvent. The electrolyte is, for example, AClO 4 , A.P.F. 6 , A.B.F. 4 , A.C.F. 3 SO 3 , AAsF 6 , AB(C 6 H 5 ) 4 , ACl, ABr, CH 3 SO 3 A, C.F. 3 SO 3 A, AN(SO 2 CF3 ) 2 , AN(SO 2 C 2 F 5 ) 2 , AC(SO 2 CF 3 ) 3 , AN(SO 3 CF 3 ) 2 etc. (A is Li or Na). The non-aqueous solvent is not particularly limited, and examples thereof include carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons, ethers, amines, esters, amides, and phosphate compounds. Representative examples of these include 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene carbonate, vinylene carbonate, methyl formate, dimethyl sulfoxide, propylene carbonate, acetonitrile, γ-butyrolactone, dimethylformamide, dimethyl carbonate, diethyl carbonate, sulfolane, ethyl methyl carbonate, 1,4-dioxane, 4-methyl-2-pentanone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methyl sulfolane, propionitrile, benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, trimethyl phosphate, triethyl phosphate, etc. These can be used alone or in combination of two or more.

[0025] (2) Solid electrolyte layer The solid electrolyte constituting the solid electrolyte layer is not particularly limited, and any solid electrolyte commonly used in all-solid-state batteries can be used. For example, 2 S.N. x S y (A is Li or Na, N is selected from P, Si, Ge, B, Al, and Ga, and x and y are integers that give a stoichiometric ratio depending on the type of M). x S y As for P 2 S 5 , SiS2 , GeS 2 , B 2 S 3 , Al 2 S 3 , Ga 2 S 3 These specific N x S y may be used alone or in combination of two or more. 2 S 5 is particularly preferred. Furthermore, A 2 S and N x S y The molar ratio of is preferably 50:50 to 90:10, more preferably 67:33 to 80:20, and further preferably 70:30 to 80:20. The solid electrolyte is A 2 S.N. x S y In addition, lithium halides and Li 3 PO 4 Lithium salts, sodium halides, Na 3 PO 4 Other solid electrolytes may be included, such as sodium salts of

[0026] The solid electrolyte may be glassy, ​​glass-ceramic, or crystalline. The term "glassy" means a substantially amorphous state. Here, "substantially" includes not only a 100% amorphous state, but also a case in which a crystalline solid electrolyte is finely dispersed in an amorphous solid electrolyte. The term "glass-ceramic" means a state that occurs when a glassy solid electrolyte is heated at a temperature equal to or higher than the glass transition point. The glass-ceramic solid electrolyte may have a crystalline portion dispersed in an amorphous glass component. The proportion of the crystalline portion may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or 80% by mass or more, based on the entire glass ceramic. The proportion of the crystalline portion may be measured by observation using a transmission electron microscope or crystal structure analysis using the Rietveld method. Furthermore, the glass-ceramic solid electrolyte may not have the glass transition point that exists in the corresponding glass-like solid electrolyte. The solid electrolyte can be formed into a solid electrolyte layer, for example, by pressing the solid electrolyte to a predetermined thickness. The pressing pressure may be selected from the range of 50 to 2000 MPa. The solid electrolyte may be made of one type or a mixture of two or more types.

[0027] In the solid electrolyte layer, A 2 S.N. x S y The ratio of is preferably 80% by mass or more, preferably 85% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 97% by mass or more, and more preferably 99% by mass or more. The thickness of the solid electrolyte layer is not particularly limited, but is preferably 5 to 1000 μm, more preferably 5 to 500 μm, more preferably 5 to 200 μm, more preferably 5 to 100 μm, more preferably 10 to 100 μm, and more preferably 10 to 50 μm. The solid electrolyte layer can be obtained, for example, by pressing a solid electrolyte powder.

[0028] (3) Manufacturing method of alkali metal battery The present invention also provides a method for producing an alkali metal battery using the electrode active material of the present invention.

[0029] (3-1) Ion battery When a non-aqueous electrolyte layer is used, an ion battery can be obtained by inserting the positive electrode and the negative electrode into a battery can and pouring a mixture of the electrolyte and the non-aqueous solvent into the battery can. A separator may be used between the positive electrode and the negative electrode. In this case, it is preferable to use a microporous polymer film. Specifically, a separator made of a polyolefin polymer such as nylon, cellulose acetate, nitrocellulose, polysulfone, polyacrylonitrile, polyvinylidene fluoride, polypropylene, polyethylene, or polybutene may be used. The positive electrode, the separator, and the negative electrode may be laminated. (3-2) All-solid-state battery An all-solid-state battery can be obtained, for example, by laminating a positive electrode, a solid electrolyte layer, and a negative electrode, pressing them to obtain a cell, and fixing the cell in a container. EXAMPLES

[0030] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto. 2 S is manufactured by Mitsuwa Chemical Co., Ltd. (purity > 99.9%), V 2 S 3 are manufactured by Kojundo Chemical Co., Ltd. (purity > 99.9%), LiCl, LiBr, LiI and Li 2 SO 4 The product used was manufactured by Aldrich (purity >99.999%). In the following examples and comparative examples, the ionic conductivity and electronic conductivity were measured using a potentiogalvanostat Solartron 1287A and an impedance analyzer 1260A manufactured by Solartron Analytical. As the X-ray diffraction apparatus, a fully automatic multipurpose X-ray diffraction apparatus SmartLab manufactured by Rigaku Corporation was used to perform structural analysis using CuKα radiation in the range of 2θ=10° to 90°. For the XPS measurement, a K-Alpha X-ray photoelectron spectroscopy (XPS) system manufactured by Thermo Fisher Scientific was used to perform the measurement using monochromated Al-Kα (1486.6 eV) X-rays. The measurement area was approximately 400 μm 2 And for charge neutralization, Ar + A neutralization gun was used to etch the sample using Ar ion species. Charging correction was based on the surface contamination of the sample (hydrocarbon, CHS, 284.7 eV). Example 1 Li 2 S and V 2 S 3 were weighed so as to have molar ratios of 93:7, 90:10, 81:19, 75:25, 70:30, 68:32, 67:33, and 59:41, and put into a planetary ball mill. After the input, eight kinds of electrode active materials were obtained by mechanochemical treatment with the planetary ball mill. As the planetary ball mill, Pulverisette P-7 manufactured by Fritsch was used. The pot and balls were made of ZrO 2 and a pot with a volume of 45 ml containing 500 balls (about 90 g) with a diameter of 4 mm was used. The mechanochemical treatment was carried out for 80 hours at an input amount of 0.3 - 0.5 g, a rotation speed of 510 rpm, room temperature, and in a dry argon glove box. The powder XRD patterns of the eight kinds of electrode active materials are shown in Fig. 2. At the bottom of Fig. 2, the XRD patterns of Li 2 S, V 2 S 3 and LiVS 2 are described. For the electrodes containing Li 2 S and V 2 S 3 with molar ratios of 81:19, 75:25, 70:30, 68:32, 67:33, and 59:41, when the electronic conductivity was measured, all showed a high conductivity exceeding the measurement upper limit of 10 -1 S cm -1 or more. On the other hand, for the electrode with a molar ratio of 90:10 having a high Li 2 S content, it showed a relatively low electronic conductivity of 4.6×10 -7 S cm -1 . Also, the one with 93:7 was 10 -7 S cm -1 or less. From this, it can be seen that even for the one with 90:10, the electronic conductivity is improved by the complexation with V 2 S 3 . The sample for measuring the electronic conductivity is a powder compact obtained by uniaxially pressing 80 mg of the obtained electrode active material powder at room temperature (25 °C) and 360 MPa.

[0031] The above-mentioned electrode was used as a positive electrode to manufacture an all-solid-state battery, and the initial charge-discharge curve of the battery was measured. The measurement conditions were: 25°C, 0.13 mA / cm 2 The charge and discharge cycle was performed at a current density of 1000 mA / s. The results are shown in Figure 3. In Figure 3, the vertical axis on the left side indicates the voltage relative to the Li-In counter electrode. The initial charge capacity and initial discharge capacity are shown in Table 1.

[0032] [Table 1]

[0033] The solid-state battery was manufactured as follows. The obtained electrode active material (3 mg) and Li 2 S.P. 2 S 5 A solid electrolyte consisting of 2 S and P 2 S 5 A two-layer pellet of a positive electrode layer and an SE layer with a diameter of 10 mm and a thickness of about 0.7 mm was obtained by pressing (at a pressure of 360 MPa) 80 mg of the SE (75:25 molar ratio with 10 mm). No SE was mixed into the positive electrode layer. The SE used was synthesized by the following method.

[0034] Li 2 S (Idemitsu Kosan Co., Ltd.: purity 99.9% or higher) and P 2 S 5 (Aldrich, purity 99%) was weighed out at 1 g in a molar ratio of 75:25 and charged into a planetary ball mill. After charging, SE was obtained by mechanochemical treatment. The planetary ball mill used was a Pulverisette P-7 manufactured by Fritsch, with a pot and balls made of zirconium oxide, and a mill with 500 balls with a diameter of 4 mm in a 45 ml pot. The dry mechanochemical treatment was carried out at a rotation speed of 510 rpm, at room temperature, and for 10 hours in a dry nitrogen glove box. This synthesis method conforms to the description of Experimental in Akitoshi Hayashi et al., Journal of Non-Crystalline Solids 356 (2010) 2670-2673.

[0035] A Li-In alloy was laminated as a negative electrode onto the laminate of the positive electrode layer and the electrolyte layer, and the laminate was sandwiched between stainless steel current collectors and pressed again (pressure 120 MPa) to obtain an all-solid-state battery.

[0036] Li in molar ratios of 67:33, 70:30, and 75:25 2 S and V 2 S 3 The results of measuring the charge / discharge curves up to five times for three types of electrodes including the above are shown in Figs. 4A to 4C. The charge and discharge capacities for the first to fifth times are also shown in Table 2. The measurement conditions were as follows: the obtained secondary battery (cell) was charged at 25°C, discharged at 0.13 mA / cm 2 The current density was set to

[0037] [Table 2]

[0038] 4A to 4C and Table 2 above, it can be seen that the charge / discharge curves change very little even after many cycles, making the battery durable against repeated charge / discharge.

[0039] Li in a molar ratio of 67:33 2 S and V 2 S 3 For an all-solid-state battery using an electrode containing the above, whether or not the charge / discharge curves differ when charging / discharging is started from a charged state and when charging / discharging is started from a discharged state was confirmed. The results are shown in Figure 5A (start of charging) and Figure 5B (start of discharging). From Figures 5A and 5B, regardless of the state from which charging / discharging is started, the charge / discharge curves hardly change, so it is presumed that no significant change has occurred in the crystal structure of the electrode active material.

[0040] Example 2 Li 2 S, V 2 S 3 and lithium salts (LiX: LiCl, LiBr, LiI or Li 2 SO 4Four kinds of electrode active materials (90(0.75Li)) were weighed out in a molar ratio of 67.5:22.5:10 in the same manner as in Example 1. 2 S 0.25V 2 S 3 )·10LiCl, 90(0.75Li 2 S 0.25V 2 S 3 )·10LiBr, 90(0.75Li 2 S 0.25V 2 S 3 )·10LiI and 90(0.75Li 2 S 0.25V 2 S 3 )·10Li 2 SO 4 The powder XRD patterns of the four electrode materials are shown in Figure 6. 2 S, V 2 S 3 , LiI and LiVS 2 The numbers in the figure represent the powder diffraction database JCPDS card numbers. 10 mg of the obtained electrode active material was pressed (pressure 360 ​​MPa) to obtain four types of pellets (positive electrodes) with a diameter of 10 mm and a thickness of approximately 0.05 mm. All-solid-state batteries were manufactured in the same manner as in Example 1, except that the above four types of positive electrodes were used, and the charge / discharge curves of the batteries were measured up to five times under the same conditions as in Example 1. The results are shown in Figures 7B to 7E. Figure 7A is a diagram using the same data as Figure 4B, and is also shown here for reference. The first to fifth charge and discharge capacities are shown in Table 3, along with the ionic conductivity of the powder compacts of each electrode active material.

[0041] [Table 3]

[0042] 7A and 7B to 7E and Table 3 show that the charge / discharge curves hardly change even after many cycles, and that the battery is resistant to repeated charge / discharge. 7A and 7B to 7E show that the charge / discharge capacity can be improved by further including a lithium salt in the electrode active material.

[0043] 90(0.75Li 2 S 0.25V 2 S 3 For an all-solid-state battery using 10LiI, the charge / discharge curve was measured up to 20 times under the same conditions as in Example 1. The results are shown in FIG. 8A. FIG. 8B shows the change in the charge / discharge capacity of the positive electrode over the number of cycles. From FIGS. 8A and B, it can be seen that the charge / discharge capacity hardly changes even after 20 cycles. The charge / discharge capacity of the above solid-state battery is 280mAhg -1 After restricting the charge / discharge capacity to 10 times, the charge / discharge curve was measured under the same conditions as in Example 1. The results are shown in Figure 9. It can be seen from Figure 9 that the charge / discharge curve does not change significantly even if the charge / discharge capacity is restricted. In addition, it can be seen from the decrease in charge potential and the increase in discharge potential that the performance improves with repeated charge / discharge.

[0044] For the above all-solid-state battery, the current density was 0.13 mA / cm up to five cycles. 2 , up to 10 times 0.64mA / cm 2 The charge / discharge curve was measured under the same conditions as in Example 1, except that the charge / discharge ratio was set to 1.3 for the first 15 cycles, 2.3 for the first 20 cycles, and 0.13 for the first 25 cycles. The results are shown in FIG. 10A. FIG. 10B shows the change in the charge / discharge capacity of the positive electrode over the number of cycles. From FIG. 10A and FIG. 10B, it can be seen that charging / discharging is possible even at high current densities. Furthermore, since the tendency of the charge / discharge capacity of the electrode is almost the same before and after charging / discharging at high current densities, it can be seen that this is an electrode active material that is unlikely to undergo structural changes even under harsh charging / discharging conditions.

[0045] As another example of the change in the charge / discharge capacity of the positive electrode over the number of cycles, 90(0.75Li 2 S 0.25V 2 S 3) 10LiI, SE 54LI 3 P.S. 4 An all-solid-state battery was fabricated using 46LiI (molar ratio) and the change in the charge / discharge capacity of the positive electrode over the number of cycles was measured. 54LI used as SE 3 P.S. 4 46LiI is LI 3 P.S. 4 and LiI were put into a planetary ball mill and subjected to mechanochemical treatment as in the SE manufacturing method described above. 2 S 0.25V 2 S 3 )·10LiI is used, and the SE is 54LI 3 P.S. 4 The same procedure was followed as in Example 1, except that 46LiI was used.

[0046] The resulting all-solid-state battery was cycled five times at a current density of 0.13 mA / cm 2 , up to 10 times 0.64mA / cm 2 , up to 15 times at 1.30mA / cm 2 , 20 times up to 2.60mA / cm 2 , 0.13mA / cm after 20 times 2 The charge / discharge curve was measured under the same conditions as in Example 1, except that: The change in the charge / discharge capacity of the positive electrode over the number of cycles is shown in FIG. 10C. As shown in FIG. 10C, even after 200 cycles, the capacity was 300 mAhg -1 It was shown that the charge / discharge capacity exceeding 10 ...

[0047] 90(0.75Li 2 S 0.25V 2 S 3 )·10LiI-based all-solid-state battery with a current density of 0.13mA / cm 211A to 11C show impedance plots before, after, and after the initial discharge of the electrode. From Fig. 11A to Fig. 11C, it can be seen that the resistance of the electrode active material is reduced after the initial discharge. This is presumably because the electrode active material is relatively soft, and the gaps (interfaces) formed during the manufacture of the electrode are reduced by the charge and discharge.

[0048] In order to examine the structural changes of the electrode active material due to charging and discharging for the above all-solid-state battery, the changes in the 2p orbital of the S atom and the 2p orbital of the V atom in the electrode were observed using plots obtained by XPS. Observations were made at five points: before charging, after the first charge, discharging to approximately 1.2 V (during discharge: discharging to approximately the same as the charge capacity), full discharge, and after the second charge. In addition, to confirm the structural changes due to the addition of LiI, 2 S·25V 2 S 3 The changes in the 2p orbital of the S atom and the 2p orbital of the V atom in the electrode before charging in the all-solid-state battery using the above were observed in the plot obtained by XPS. The results are shown in Figures 12A and 12B. From Figures 12A and 12B, the following can be inferred. (1) 90 (0.75Li) before charging 2 S 0.25V 2 S 3 ) 10LiI and 75Li 2 S·25V 2 S 3 Comparing the profiles of the 2p orbitals, the addition of LiI hardly changes the electronic states of S and V. (2) The profile of the 2p orbital of the S atom shows that polysulfides are formed during charging. It can also be seen that the amount of polysulfides is greater after the second charge than after the first charge. (3) In the profile of the 2p orbital of the S atom, no peaks corresponding to polysulfides are observed during discharge. 2 A peak is observed suggesting the production of S. (4) From the profile of the 2p orbital of the S atom, when fully discharged, Li 2 S(S 2-This shows that the oxidation and reduction of sulfur occurs, which contributes to the increase in capacity. (5) From the profiles of the 2p orbital of V atom before charging, after the first charging, and after the second charging, it can be seen that each peak shifts slightly to the higher energy side by charging. From this shift, it is inferred that V is oxidized by charging.

[0049] Example 3 Li 2 S and V 2 S 3 An all-solid-state battery was manufactured in the same manner as in Example 2, except that the molar ratio of was changed to 0.70:0.30, and the charge / discharge curve of the battery was measured up to five times under the same conditions as in Example 1. The results are shown in Figure 13. The charge capacities and discharge capacities of the first to fifth times are shown in Table 4.

[0050] [Table 4]

[0051] From FIG. 13 and Table 4 above, it can be seen that the charge / discharge curve hardly changes even after many cycles, and that the battery is resistant to repeated charge / discharge.

[0052] Example 4 Li 2 S, V 2 S 3 and Li 2 SO 4 The molar ratio of Li was 63:27:10. 2 S, V 2 S 3 , LiI and Li 2 SO 4 An all-solid-state battery was manufactured in the same manner as in Example 2, except that the molar ratio of was changed to 56:24:10:10, and the charge / discharge curve of the battery was measured up to five times under the same conditions as in Example 1. The results are shown in Figures 14A and 14B. The charge capacities and discharge capacities of the first to fifth times are shown in Table 5.

[0053] [Table 5]

[0054] 14A and 14B, and Table 5 above, it can be seen that the charge / discharge curves change very little even after many cycles, and that the battery is resistant to repeated charge / discharge.

[0055] Example 5 Li 2 S, V 2 S 3 The electrode active material (Li, 3 VS 4 ) and electrodes were obtained. Also, Li 2 S, V 2 S 3 , S and lithium salts (LiI or Li 2 SO 4 The two electrode active materials (90Li) were weighed in a molar ratio of 45:15:30:10 in the same manner as in Example 2. 3 VS 4 10LiI, 90Li 3 VS 4 10Li 2 SO 4 ) and a positive electrode were obtained. Furthermore, Li 2 S, V 2 S 3 , S and lithium salts (Li 2 SO 4 The electrode active material (80Li) was weighed in a molar ratio of 40:13.6:26.4:20 in the same manner as in Example 2. 3 VS 4 20Li 2 SO 4 ) and a positive electrode were obtained. The XRD patterns of these four electrode active materials are shown in Figures 15A and 15B. 2 S, V 2 S 3 , LiI and Li 2 SO 4 The XRD patterns of the above are shown. 15A and 15B, by adding lithium salt, the XRD pattern changes to Li 3 VS 4 It can be seen that there is no significant change from Li 2 The peak corresponding to S is slightly broadened, which indicates that the addition of lithium salt causes the material to become amorphous. Except for using four types of electrode active materials, the charge / discharge curves were measured twice in the same manner as in Example 1. The results are shown in Figures 16A to 16D. The first and second charge capacities and discharge capacities are shown in Table 6.

[0056] [Table 6]

[0057] From FIG. 16A to FIG. 16D and Table 6 above, Li 3 VS 4 16B, 16C, and 16D, it can be seen that by adding a lithium salt to LiI, the charge / discharge curve hardly changes even after many cycles, and a battery that is strong against repeated charge / discharge can be obtained. 2 SO 4 It can be seen that the initial charge capacity can be improved compared to the conventional method.

[0058] Example 6 Na 2 S (Naganosha) and V 2 S 3 The electrode active material 75Na was prepared in the same manner as in Example 1, except that the molar ratio of 2 S·25V 2 S 3 Also, Na 2 S, V 2 S 3 Electrode active material 90 (0.75NaI) was weighed out in a molar ratio of 67.5:22.5:10 in the same manner as in Example 1. 2 S 0.25V 2 S 3The powder XRD patterns of these electrode active materials are shown in Figure 17. 2 The XRD pattern of S is also shown.

[0059] The ionic conductivity of the obtained electrode active material was measured by producing an ionic conductivity measuring cell. The ionic conductivity measuring cell was produced as follows. Manufactured 75Na 2 S·25V 2 S 3 40 mg of the pellet was pressed at a pressure of 100 MPa for 1 minute using a uniaxial hydraulic press to obtain a pellet. 3 P.S. 4 The glass ceramic solid electrolyte was attached to each of them and pressed at a pressure of 370 MPa for 3 minutes. 3 P.S. 4 A 30 mg Na-Sn alloy was laminated on the glass ceramic solid electrolyte, sandwiched between stainless steel current collectors, and pressed again (at a pressure of 100 MPa) to produce a cell for measuring ionic conductivity. 3 P.S. 4 The glass ceramic solid electrolyte is Na 2 S and P 2 S 5 The mixture was weighed out in a molar ratio of 75:25, put into a planetary ball mill, and subjected to mechanochemical treatment. 2 S·25V 2 S 3 Instead of 90(0.75Na 2 S 0.25V 2 S 3 )·10NaI was also used to fabricate a cell.

[0060] The ionic conductivity was measured using the two types of cells. 3 VS 3 The ionic conductivity of the cell using Na =4.2×10 -6 Scm -1 90(0.75Na 2 S 0.25V 2 S3 The ionic conductivity of the cell using 10NaI is σ Na =5.4×10 -6 Scm -1 It was.

[0061] The obtained 75Na 2 S·25V 2 S 3 And Na 3 P.S. 4 The glass ceramic solid electrolyte was mixed at a weight ratio of 7: 3. 10 mg of this mixture was pressed (pressure 360 ​​MPa) to obtain a pellet (positive electrode) with a diameter of 10 mm and a thickness of approximately 0.05 mm. This positive electrode and Na as a solid electrolyte 3 P.S. 4 An all-solid-state battery was manufactured in the same manner as in Example 1, except that a glass ceramic solid electrolyte and a Na-Sn alloy were used as the negative electrode. 2 S·25V 2 S 3 Instead of 90(0.75Na 2 S 0.25V 2 S 3 )·10NaI was also used to fabricate an all-solid-state battery.

[0062] The initial charge / discharge curves of the two types of all-solid-state batteries manufactured were measured. The battery measurement conditions were the same as in Example 1, except that charge / discharge was performed at 60° C. The measurement results are shown in FIG. 18 and FIG. 19, respectively. As shown in FIG. 18 and FIG. 19, both all-solid-state batteries had an initial charge / discharge curve of 200 mAhg -1 It was shown that the charge / discharge capacity was higher than or equal to the above.

Claims

1. The following formula: A ａ１ MS ａ２ X ａ３ (wherein A is selected from Li and Na, M is selected from V, Nb, Ti and Mo, and X is Cl, Br, I and SO ４ a1 is 2 or more and 4 or less, a2 is 2.5 or more and 5 or less, and a3 is 0.05 or more and 0.6 or less. An electrode active material for an alkali metal battery, characterized in that it is represented by the formula:

2. A includes Li, M includes V, and X includes Cl, Br, I, and SO. ４ The electrode active material for an alkali metal battery according to claim 1 , comprising any one selected from the group consisting of:

3. 3. The electrode active material for an alkali metal battery according to claim 1, wherein a1 is from 2.5 to 3.5, a2 is from 2.5 to 4, and a3 is from 0.1 to 0.

45.

4. The formula: A ａ１ MS ａ２ X ａ３ But (Li ２ S) ｂ１ - (V ２ S ３ ) ｂ２ -(Li ｃ X) ｂ３ (b1 / b2 is 1 to 9, b3 / b2 is 0.1 to 1.5, and c is 1 to 2).

5. A includes Na, M includes V, and X includes Cl, Br, I, and SO ４ The electrode active material for an alkali metal battery according to claim 1 , comprising any one selected from the group consisting of:

6. The electrode active material for an alkali metal battery according to any one of claims 1 to 5, wherein the alkali metal battery is an all-solid-state battery.

7. The electrode active material for an alkali metal battery according to any one of claims 1 to 6, wherein the alkali metal battery comprises a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode, and the positive electrode does not contain a solid electrolyte.

8. An electrode for an alkali metal battery comprising the electrode active material according to any one of claims 1 to 7.

9. The battery includes a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode, An alkali metal battery in which the positive electrode or the negative electrode or both contain the electrode active material according to any one of claims 1 to 7.

10. 10. The alkali metal battery of claim 9, wherein the electrolyte layer comprises a solid electrolyte layer.

Images