Electrode composite material and sodium ion battery

Abstract

The invention discloses an electrode composite material and a sodium ion battery. The electrode composite material of the present disclosure comprises: an alloy of tin and cobalt; and a carbon material. In the electrode composite material of the present disclosure, in the XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase, and in the XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the Sn phase. The sodium ion battery of the present disclosure has: a negative electrode active material layer comprising the electrode composite material of the present disclosure; an electrolyte layer containing sodium ions; and a positive electrode active material layer.

Description

Technical Field

[0001] The present disclosure relates to electrode composites and sodium ion batteries. Background Art

[0002] As disclosed in Japanese Patent Application Laid-Open No. 2015-022983, a battery using a tin-cobalt alloy as a negative electrode active material is known. Summary of the Invention

[0003] Batteries using a tin-cobalt alloy as a negative electrode active material still have room for improvement from the perspective of increasing capacity.

[0004] An object of the present disclosure is to provide an electrode composite material capable of improving the capacity of a battery and a sodium ion battery having such an electrode composite material.

[0005] The present inventors have discovered that the above-mentioned problems can be solved by the following means.

[0006] <Method 1>

[0007] An electrode composite material comprising:

[0008] Alloys of tin and cobalt; and

[0009] Carbon materials,

[0010] Furthermore, in the XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase.

[0011] <Method 2>

[0012] In the electrode composite material according to embodiment 1, in an XRD spectrum, the ratio of the peak intensity of the CoSn2 phase to the peak intensity of the CoSn phase is 1.1 or more.

[0013] <Method 3>

[0014] The electrode composite material according to embodiment 1 or 2, wherein in an XRD spectrum, the ratio of the sum of the peak intensity of the CoSn2 phase and the peak intensity of the Sn phase to the peak intensity of the CoSn phase is 1.5 to 6.0.

[0015] <Method 4>

[0016] In the electrode composite material according to any one of aspects 1 to 3, a ratio of the mass of the tin to the total mass of the tin and the cobalt is 0.7 or more.

[0017] <Method 5>

[0018] A sodium ion battery having:

[0019] A negative electrode active material layer comprising the electrode composite material according to any one of embodiments 1 to 4;

[0020] an electrolyte layer comprising sodium ions; and

[0021] Positive electrode active material layer.

[0022] According to the present disclosure, it is possible to provide an electrode composite material capable of improving the capacity of a battery and a sodium ion battery having such an electrode composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like numerals denote like elements.

[0024] Figure 1 This is a schematic diagram showing an example of the sodium ion battery of the present disclosure.

[0025] Figure 2 1 and 2 are XRD spectra of the electrode composite materials of Production Example 1 and Comparative Production Example 1.

[0026] Figure 3 It is a graph showing the relationship between the ratio of the sum of the peak intensity of the CoSn2 phase and the peak intensity of the Sn phase to the peak intensity of the CoSn phase ((CoSn2 phase + Sn phase) / CoSn phase (peak intensity)) and the charge capacity in the sodium ion batteries of the examples and comparative examples.

[0027] Figure 4 This is a graph showing the relationship between the ratio of the mass of tin to the total mass of tin and cobalt (Sn / Sn+Co (mass)) and the charge capacity in the sodium ion batteries of Examples and Comparative Examples. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present disclosure in detail. However, the present disclosure is not limited to the following embodiments, and can be implemented with various modifications within the scope of the disclosed gist.

[0029] [Electrode composite materials]

[0030] The electrode composite material disclosed herein comprises: an alloy of tin and cobalt; and a carbon material. In the electrode composite material disclosed herein, in an XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase.

[0031] The present inventors have completed the present disclosure by unexpectedly focusing on the presence of CoSn2 phase in tin-cobalt (Sn-Co) alloys. Specifically, it was found that by increasing the proportion of CoSn2 phase, the capacity of the battery can be improved. As the reason for this, although not intending to be bound by any theory, it is believed that this is because in the electrode composite material of the present disclosure, the crystalline phase is properly controlled so that tin easily participates in charge and discharge. Furthermore, in the present disclosure, the so-called capacity particularly refers to the charging capacity.

[0032] <Tin and cobalt alloy>

[0033] The electrode composite material disclosed herein comprises an alloy of tin and cobalt (Sn-Co alloy). The Sn in the Sn-Co alloy has the function of absorbing and desorbing diffuse ions such as lithium ions and sodium ions, and thus participates in the charge and discharge of the battery. In other words, Sn functions as an electrode active material. The Co in the Sn-Co alloy can help improve the cycle characteristics of the battery.

[0034] In the electrode composite material of the present disclosure, in the XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase. In particular, in the XRD spectrum, the ratio of the peak intensity of the CoSn2 phase to the peak intensity of the CoSn phase (CoSn2 phase / CoSn phase (peak intensity)) can be 1.1 or more. The ratio can be more than 1.5, more than 2.0 or more than 2.5, and can be less than 5.0, less than 4.5 or less than 4.0. By being set to such a structure, the capacity of the battery can be improved.

[0035] The ratio of the peak intensity of the CoSn2 phase to the peak intensity of the Sn phase (CoSn2 phase / Sn phase (peak intensity)) can be 1.0 or more, 1.5 or more, 2.0 or more, 2.5 or more, or 3.0 or more, and can be 5.0 or less, 4.8 or less, or 4.5 or less. By setting such a configuration, the capacity of the battery can be improved without excessively impairing the cycle characteristics.

[0036] The ratio of the sum of the peak intensity of the CoSn2 phase and the peak intensity of the Sn phase to the peak intensity of the CoSn phase ((CoSn2 phase + Sn phase) / CoSn phase (peak intensity)) can be 1.5 or more and 6.0 or less. This ratio can be particularly 1.7 or more, 2.0 or more, 2.5 or more, or 3.0 or more, and can be 5.8 or less, 5.5 or less, or 5.0 or less. By setting it to such a configuration, the capacity of the battery can be improved without excessively impairing the cycle characteristics.

[0037] The method for measuring the peak intensity of each phase using X-ray diffraction (XRD) is not particularly limited. For example, the peak intensity of each phase can be determined as follows, using the average value of the peak intensity at 26 to 26.5° in the XRD spectrum as the background value:

[0038] Peak intensity of the CoSn phase: a value obtained by subtracting the background value from the maximum value of the peak intensity at 33.8 to 34.2°.

[0039] The peak intensity of the CoSn2 phase is a value obtained by subtracting the background value from the maximum value of the peak intensity at 32.7 to 32.9°.

[0040] The peak intensity of the Sn phase is a value obtained by subtracting the background value from the maximum value of the peak intensity at 30.3 to 30.9°.

[0041] The XRD spectrum may be a spectrum based on a diffraction peak obtained by X-ray diffraction using CuKα rays as specific X-rays and setting the scanning speed to 1° / min.

[0042] The ratio of the mass of tin to the total mass of tin and cobalt (Sn / (Sn+Co) (mass)) can be 0.7 or greater. This ratio can particularly be 0.75 or greater, and can be less than 1.0, 0.9 or less, 0.85 or less, or 0.80 or less. By adopting such a configuration, the battery capacity can be improved without excessively impairing the cycle characteristics.

[0043] The mass of tin and cobalt can be quantified by energy dispersive X-ray fluorescence spectrometry (EDX) and high-frequency inductively coupled plasma (ICP) emission spectrometry.

[0044] <Carbon Materials>

[0045] The electrode composite material disclosed herein comprises a carbon material. The carbon material functions as a matrix for the Sn-Co alloy. The carbon material may be amorphous, in which case the carbon material may not participate in the charge and discharge of the battery.

[0046] The content of the carbon material may be 10% by mass or more and 30% by mass or less. The content of the carbon material may be 11% by mass or more, 12% by mass or more, 13% by mass or more, 14% by mass or more, 15% by mass or more, or 16% by mass or more, and may be 28% by mass or less, 26% by mass or less, 24% by mass or less, 22% by mass or less, or 20% by mass or less.

[0047] The content of the carbon material can be quantified using a carbon-sulfur analyzer (CS meter) by a combustion method, for example.

[0048] [Method for producing electrode composite material]

[0049] The method for producing the electrode composite material disclosed herein is not particularly limited, and an example thereof includes a method of mixing tin, cobalt, and a carbon material by mechanical alloying. More specifically, an example thereof includes a method of mixing tin, cobalt, and a carbon material in an inert gas atmosphere using a ball mill at a predetermined rotational speed for a predetermined time.

[0050] In the above-mentioned method, for example, the crystal phase in the Sn—Co alloy can be controlled by adjusting the amounts of the tin element and the cobalt element used.

[0051] [Sodium-ion battery]

[0052] like Figure 1 As illustrated, the sodium ion battery 1 of the present disclosure includes: a negative electrode active material layer 20 containing the electrode composite material of the present disclosure; an electrolyte layer 30 containing sodium ions; and a positive electrode active material layer 40. The sodium ion battery of the present disclosure may include a negative electrode current collector layer 10, a negative electrode active material layer 20 containing the electrode composite material of the present disclosure, an electrolyte layer 30, a positive electrode active material layer 40, and a positive electrode current collector layer 50.

[0053] The battery disclosed herein may be a liquid-based battery or a solid-state battery. Furthermore, in this disclosure, "solid-state battery" refers to a battery that uses at least a solid electrolyte as its electrolyte. Therefore, a solid-state battery may also use a combination of a solid electrolyte and a liquid electrolyte as its electrolyte. Furthermore, the solid-state battery disclosed herein may also be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as its electrolyte.

[0054] Examples of the shape of the sodium ion battery of the present disclosure include a coin shape, a laminate shape, a cylindrical shape, and a square shape.

[0055] The elements constituting the sodium ion battery of the present disclosure are described below.

[0056] <Negative Electrode Collector Layer>

[0057] Examples of the material for the negative electrode current collector layer include SUS (stainless steel), aluminum, copper, nickel, and carbon.

[0058] The negative electrode current collector layer may be in a foil, mesh, or porous form, for example.

[0059] <Negative Electrode Active Material Layer>

[0060] The negative electrode active material layer comprises the electrode composite material of the present disclosure. The negative electrode active material layer of the present disclosure may optionally comprise a conductive additive and a binder. In the case where the sodium ion battery of the present disclosure is a solid battery, the negative electrode active material layer may optionally comprise a solid electrolyte.

[0061] (Electrode Composite Materials)

[0062] Regarding the electrode composite material, reference can be made to the above description regarding the electrode composite material of the present disclosure.

[0063] The content of the electrode composite material may be 50 mass % or more, 70 mass % or more, 80 mass % or more, 90 mass % or more, or less than 100 mass %, 99 mass % or less, 95 mass % or less, or 90 mass % or less.

[0064] <Conductive additive>

[0065] Conductive additives may be, for example, carbon materials or metal materials. Specific examples of carbon materials include carbon black such as acetylene black, Ketjen black, furnace black, and thermal black; carbon fibers such as VGCF; graphite; hard carbon; and coke. Metal materials include Fe, Cu, Ni, and Al. Any one of these materials may be used alone, or a combination of multiple materials may be used. The content of the conductive additive in the negative electrode active material layer is not particularly limited and may be appropriately determined based on the desired conductivity.

[0066] <Adhesive>

[0067] As the binder, any chemically and electrically stable binder may be used. Specific examples of the binder include fluorine-based binders such as polyvinylidene fluoride (PVdF)-based binders and polytetrafluoroethylene (PTFE)-based binders; rubber-based binders such as styrene butadiene rubber (SBR)-based binders; olefin-based binders such as polypropylene (PP)-based binders and polyethylene (PE)-based binders; cellulose-based binders such as carboxymethyl cellulose (CMC)-based binders; and polyacrylic acid (PAA)-based binders. One of these may be used alone, or a plurality of them may be mixed and used. The content of the binder in the negative electrode active material layer is not particularly limited, and may be appropriately determined according to the target adhesiveness.

[0068] <Solid Electrolyte>

[0069] The solid electrolyte may be an inorganic solid electrolyte. Examples of inorganic solid electrolytes include oxide solid electrolytes and sulfide solid electrolytes. Examples of oxide solid electrolytes include Na3Zr2Si2PO4 12 Nasion compounds and β-alumina (Na2O-11Al2O3) are also available. Examples of sulfide solid electrolytes include Na2S-P2S5. The solid electrolyte may be in the form of particles, for example.

[0070] The negative electrode active material layer may have a certain thickness. The thickness of the negative electrode active material layer is not particularly limited, and may be, for example, 0.1 μm or more and 1 mm or less.

[0071] <Electrolyte Layer>

[0072] When the battery of the present disclosure is a liquid-based battery, the electrolyte layer can be formed by impregnating the separator with the electrolyte solution.

[0073] (diaphragm)

[0074] The material of the separator is not particularly limited as long as it has the function of electrically separating the negative electrode active material layer from the positive electrode active material layer. Examples include porous sheets composed of resins such as polyethylene (PE), polypropylene (PP), polyester, cellulose, and polyamide, as well as porous insulating materials such as non-woven fabrics and glass fiber non-woven fabrics, or combinations thereof. The thickness of the separator is not particularly limited, and for example, it can be 5 μm or more and 1 mm or less.

[0075] (Electrolyte)

[0076] The electrolyte may contain a sodium salt and a non-aqueous solvent. Examples of the sodium salt include inorganic sodium salts such as NaPF6, NaBF4, NaClO4, and NaAsF6; and organic sodium salts such as NaCF3SO3, NaN(CF3SO2)2, NaN(C2F5SO2)2, NaN(FSO2)2, and NaC(CF3SO2)3.

[0077] As nonaqueous solvent, as long as it is the solvent of dissolving sodium salt, just not particularly limited.As nonaqueous solvent, can illustrate high dielectric constant solvent and low dielectric constant solvent.As high dielectric constant solvent, for example, can enumerate cyclic ester (cyclic carbonate), gamma-butyrolactone, cyclopentane, N-methyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI) etc. of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) etc. As low dielectric constant solvent, for example, can enumerate the ether etc. of the acetic ester (chain carbonate), methyl acetate, ethyl acetate etc. of the chain ester (chain carbonate) of dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC) etc., 2-methyltetrahydrofuran etc. etc..Also can use the mixed solvent that high dielectric constant solvent and low dielectric constant solvent are mixed.

[0078] When the battery of the present disclosure is a solid battery, the electrolyte layer contains a solid electrolyte and may optionally contain a conductive auxiliary agent, a binder, and the like.

[0079] Regarding the solid electrolyte, the conductive additive, and the binder, reference can be made to the above description regarding the negative electrode active material layer of the present disclosure.

[0080] <Positive Electrode Active Material Layer>

[0081] The positive electrode active material layer contains a positive electrode active material and may optionally contain a conductive auxiliary agent, a binder, etc. When the battery of the present disclosure is a solid battery, the positive electrode active material layer may optionally contain a solid electrolyte.

[0082] As the positive electrode active material, a material that exhibits a high potential with respect to the negative electrode active material can be used. Examples of such positive electrode active materials include Na-containing oxides such as layered active materials, spinel-type active materials, and olivine-type active materials. Specifically, NaFeO2, NaNiO2, NaCoO2, NaMnO2, NaVO2, Na(Ni X Mn 1-X )O2(0 < X < 1), Na(Fe X Mn 1-X )O2(0 < X < 1), NaVPO4F, Na2FePO4F, Na3V2(PO4)3, etc. can be cited.

[0083] The content of the positive electrode active material can be 50% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, and can be less than 100% by mass, 99% by mass or less, 95% by mass or less, or 90% by mass or less.

[0084] The shape of the positive electrode active material is not particularly limited. For example, it can be in the form of particles. In this case, its average particle diameter can be, for example, 1 nm or more or 10 nm or more, and can be 100 μm or less or 30 μm or less.

[0085] Regarding the conductive auxiliary agent, the binder, and the solid electrolyte, reference can be made to the above description regarding the negative electrode active material layer of the present disclosure.

[0086] The positive electrode active material layer can have a certain thickness. The thickness of the positive electrode active material layer is not particularly limited. For example, it can be 0.1 μm or more and 1 mm or less.

[0087] <Positive electrode current collector layer>

[0088] Examples of the material for the positive electrode current collector layer include SUS, aluminum, nickel, iron, titanium, carbon, etc.

[0089] The positive electrode current collector layer can be, for example, in the form of a foil, a net, a porous material, etc.

[0090] <Other components>

[0091] The sodium ion battery of the present disclosure can include a battery case for housing the layers of the battery and terminals connected to the current collector, etc. In addition, in order to reduce the contact resistance, the battery of the present disclosure can include a constraint member for constraining each layer in the stacking direction. Regarding these members, the same members as those in the prior art can be used.

[0092] [Battery Manufacturing Method]

[0093] A method of manufacturing the sodium ion battery of the present disclosure may include forming a negative active material layer including the electrode composite material of the present disclosure.

[0094] The method for forming the negative electrode active material layer may be a wet method or a dry method.

[0095] The method for forming a negative electrode active material layer in a wet process may include: providing a negative electrode mixture slurry containing a mixture and a dispersion medium, wherein the mixture includes the electrode composite material disclosed herein; and applying the negative electrode mixture slurry to a substrate, and then drying and removing the dispersion medium.

[0096] The dispersion medium is not particularly limited, and examples thereof include alcohols, glycols, cellosolves, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, phosphoric acid esters, ethers, and nitriles, with specific examples being ethanol, 2-propanol, methyl ethyl ketone, and N-methyl-2-pyrrolidone.

[0097] The drying temperature, drying time, and the like can be appropriately designed depending on the boiling point and the amount of the dispersion medium used.

[0098] The method of forming the negative electrode active material layer in a dry process may include forming a powder compact containing a mixture of the electrode composite material on a substrate.

[0099] Regarding the electrode composite material in the method of forming the negative electrode active material layer, reference can be made to the above description regarding the electrode composite material of the present disclosure.

[0100] The substrate is not particularly limited, and may be, for example, a negative electrode current collector layer.

[0101] [Production Example 1]

[0102] <Production of Electrode Composite Material>

[0103] The raw materials composed of tin element, cobalt element and carbon material are weighed in a manner to obtain a target composition ratio. The total mass of the raw materials is 15 g. 400 g of SUS balls and the weighed raw materials are added to a 500 mL container made of chrome steel. The container is sealed after being replaced with argon gas, and the raw materials are treated by mechanical alloying for 25 hours at a speed of 250 rpm. After treatment, the material in the container is recovered and classified using a net with a mesh size of 53 μm. Thus, the electrode composite material of Manufacturing Example 1 is obtained.

[0104] <Quantitative determination of tin and cobalt>

[0105] Energy dispersive X-ray fluorescence (EDX) and high-frequency inductively coupled plasma (ICP) emission spectrometry were used to quantify the amounts of tin and cobalt in the obtained electrode composite material.

[0106] <Measurement of Peak Intensity>

[0107] The peak intensity of each crystalline phase of the tin-cobalt alloy was measured using X-ray diffraction (XRD). Specifically, the average value of the peak intensity at 26 to 26.5° in the XRD spectrum was used as the background value, and the peak intensity of each phase was calculated as follows:

[0108] Peak intensity of the CoSn phase: a value obtained by subtracting the background value from the maximum value of the peak intensity at 33.8 to 34.2°.

[0109] The peak intensity of the CoSn2 phase is a value obtained by subtracting the background value from the maximum value of the peak intensity at 32.7 to 32.9°.

[0110] The peak intensity of the Sn phase is a value obtained by subtracting the background value from the maximum value of the peak intensity at 30.3 to 30.9°.

[0111] The XRD spectrum is a spectrum based on diffraction peaks obtained by X-ray diffraction using CuKα rays as specific X-rays and setting the scanning speed to 1° / min.

[0112] [Production Examples 2 to 5 and Comparative Production Examples 1 to 3]

[0113] The electrode composite materials of Manufacturing Examples 2 to 5 and Comparative Manufacturing Examples 1 to 3 were obtained by following the same procedure as in Manufacturing Example 1 except that the peak intensity of the crystalline phase of the tin-cobalt alloy and the ratio of the mass of tin to the total mass of tin and cobalt (Sn / (Sn+Co)(mass)) were changed as shown in Table 1.

[0114] [Examples 1 to 5 and Comparative Examples 1 to 3]

[0115] <Production of Evaluation Cell>

[0116] These substances were weighed in a mass ratio of 85 / 10 / 5 for the electrode composite material / acetylene black (AB) / polyvinylidene fluoride (PVdF) of each manufacturing example and comparative manufacturing example, and dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry. The obtained slurry was applied to an aluminum foil as a collector foil, pressed, and then vacuum-dried at 120°C overnight to prepare a test electrode. As a counter electrode, a metallic sodium foil was used. As an electrolyte, a 1M solution obtained by dissolving NaPF6 in PC was used. Thus, electrochemical measurement coin-type units (CR2032) of Examples 1 to 5 and Comparative Examples 1 to 3 were produced. Furthermore, the numbers of each manufacturing example and comparative manufacturing example correspond to the numbers of the embodiments and comparative examples, respectively.

[0117] <Evaluation of Charging Capacity>

[0118] The charge capacity of the evaluation cell for each example was evaluated at a rate of 0.1C over a voltage range of 0.05V to 1.5V. The evaluation was performed in a thermostatic chamber at 25°C. The charge capacity refers to the capacity during the initial sodium doping reaction. The evaluation results are shown relative to the value for Comparative Example 1, which was set to 1.00.

[0119] <Results>

[0120] The XRD spectra of the electrode composite materials of Preparation Example 1 and Comparative Preparation Example 1 are shown in FIG. Figure 2 The relationship between CoSn2 phase / CoSn phase (peak intensity), CoSn2 phase / Sn phase (peak intensity), (CoSn2 phase + Sn phase) / CoSn phase (peak intensity) and Sn / (Sn+Co) (mass) and charge capacity of each example is shown in Tables 1 and Figure 3 as well as Figure 4 .

[0121] Table 1

[0122]

[0123] like Figure 2 As shown, in the electrode composite material of Manufacturing Example 1, the peak intensity of the CoSn2 phase in the XRD spectrum is greater than the peak intensity of the CoSn phase. The same is true for the electrode composite materials of Manufacturing Examples 2 to 5. In contrast, in the electrode composite material of Comparative Manufacturing Example 1, the peak intensity of the CoSn2 phase in the XRD spectrum is smaller than the peak intensity of the CoSn phase. The same is true for the electrode composite materials of Comparative Manufacturing Examples 2 and 3.

[0124] As shown in Table 1, the battery of the embodiment of the electrode composite material having the manufacturing example in which the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase has a larger charging capacity than the battery of the comparative example of the electrode composite material having the comparative manufacturing example in which the peak intensity of the CoSn2 phase is smaller than the peak intensity of the CoSn phase.

Claims

1. An electrode composite material comprising: Alloys of tin and cobalt; and Carbon materials, Furthermore, in the XRD spectrum, the peak intensity of the CoSn2 phase is greater than the peak intensity of the CoSn phase.

2. The electrode composite material according to claim 1, In the XRD spectrum, the ratio of the peak intensity of the CoSn2 phase to the peak intensity of the CoSn phase is 1.1 or more.

3. The electrode composite material according to claim 1, In the XRD spectrum, the ratio of the sum of the peak intensity of the CoSn2 phase and the peak intensity of the Sn phase to the peak intensity of the CoSn phase is 1.5 or more and 6.0 or less.

4. The electrode composite material according to claim 1, The ratio of the mass of the tin to the total mass of the tin and the cobalt is 0.7 or more.

5. A sodium ion battery comprising: A negative electrode active material layer comprising the electrode composite material according to any one of claims 1 to 4; an electrolyte layer comprising sodium ions; and Positive electrode active material layer.

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