Electrode material, electrode containing the same, and secondary battery containing the same

Abstract

In a secondary battery having a solid electrolyte, the present invention provides a means for reducing the resistance of the battery. [Solution] An electrode material comprising an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, wherein the electrode active material and the inorganic solid electrolyte are coated with the organic solid electrolyte, the organic solid electrolyte comprises a polymer compound and an alkali metal salt, and the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 40 to 90% by mass.

Description

[Technical Field]

[0001] The present invention relates to an electrode material, an electrode containing the same, and a secondary battery containing the same. [Background technology]

[0002] In recent years, research and development on secondary batteries using oxide-based or sulfide-based solid electrolytes has been actively pursued. Solid electrolytes are materials mainly composed of ionic conductors capable of ion conduction in a solid state. Therefore, secondary batteries using solid electrolytes have the advantage that, in principle, various problems caused by flammable organic electrolytes do not occur, unlike conventional liquid-based batteries using non-aqueous electrolytes.

[0003] In secondary batteries using solid electrolytes, ionic conductivity is achieved through contact between particles via the solid electrolyte. This presents a problem in that it is difficult to ensure the desired ionic conductivity compared to conventional liquid-based secondary batteries.

[0004] Patent Document 1 discloses a battery in which at least one of the surfaces of the positive electrode active material particles and the negative electrode active material particles is coated with a polyether-based organic solid electrolyte, which is a compound of a polymer compound having ether bonds and an electrolyte salt. It is said that this configuration reduces the gaps between the active materials and the gaps between the active materials and the solid electrolyte, thereby improving the charge and discharge characteristics of the battery. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-197590 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, upon examination by the present inventors, it has been found that the techniques disclosed in the above-mentioned documents may also cause a problem that the reduction of the resistance of the battery is not sufficient.

[0007] Therefore, an object of the present invention is to provide a means capable of reducing the resistance of a secondary battery including a solid electrolyte.

Means for Solving the Problems

[0008] The present inventors have conducted intensive studies to solve the above problems. As a result, in a secondary battery including a solid electrolyte, by coating an electrode active material and an inorganic solid electrolyte with an organic solid electrolyte and further controlling the content of an alkali metal salt in the organic solid electrolyte within a predetermined range, it has been found that the above problems can be solved, and the present invention has been completed.

[0009] [[ID=I5]]That is, one aspect of the present invention relates to an electrode material including an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte. In the electrode material, the electrode active material and the inorganic solid electrolyte are coated with the organic solid electrolyte. Further, the organic solid electrolyte includes a polymer compound and an alkali metal salt, and is characterized in that the content of the alkali metal salt in the organic solid electrolyte is 40 to 90% by mass.

Effects of the Invention

[0010] According to the electrode material according to one aspect of the present invention, the resistance of the battery can be reduced.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is a cross-sectional view schematically showing the overall structure of a laminated (internally parallel-connected type) all-solid-state secondary battery according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0012] One embodiment of the present invention is an electrode material comprising an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, wherein the electrode active material and the inorganic solid electrolyte are coated with the organic solid electrolyte, and the organic solid electrolyte comprises a polymer compound and an alkali metal salt, and the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 40 to 90% by mass. According to this embodiment, the resistance of the battery can be reduced.

[0013] <Electrode material> [Electrode active material] The electrode material is the material that constitutes the electrode active material layer, described later, and essentially includes electrode active material, inorganic solid electrolyte, and organic solid electrolyte. When the electrode material is a positive electrode material, the electrode active material contained in the electrode material is the positive electrode active material. When the electrode material is a negative electrode material, the electrode active material contained in the electrode material is the negative electrode active material.

[0014] (Cathode active material) The type of positive electrode active material contained in the positive electrode active material layer is not particularly limited, but includes layered rock salt type active materials such as LiCoO2, LiMnO2, LiNiO2, LiVO2, Li(Ni-Mn-Co)O2, LiMn2O4, LiNi 0.5 Mn 1.5 Examples of active materials include spinel-type active materials such as O4, olivine-type active materials such as LiFePO4 and LiMnPO4, and Si-containing active materials such as Li2FeSiO4 and Li2MnSiO4. Other oxide active materials include, for example, Li4Ti5O 12 These include Li(Ni-Mn-Co)O2 and those in which some of these transition metals are substituted with other elements (hereinafter also simply referred to as "NMC composite oxides") are preferably used as positive electrode active materials.

[0015] Another preferred embodiment involves the use of a sulfur-based cathode active material. Examples of sulfur-based cathode active materials include particles or thin films of organic sulfur compounds or inorganic sulfur compounds, and any material that can release lithium ions during charging and absorb lithium ions during discharging by utilizing the oxidation-reduction reaction of sulfur is acceptable.

[0016] (Negative electrode active material) Examples of negative electrode active materials include carbon materials, metal oxides, and metal active materials. Lithium-containing active materials may also be used as negative electrode active materials. Examples of lithium-containing negative electrode active materials include lithium metal and lithium-containing alloys. Examples of lithium-containing alloys include alloys of Li with at least one of In, Al, Si, Sn, Mg, Au, Ag, and Zn. The negative electrode active material preferably contains lithium metal or a lithium-containing alloy, a silicon-based negative electrode active material, or a tin-based negative electrode active material, and is particularly preferably lithium metal or a lithium-containing alloy.

[0017] The content of the electrode active material in the electrode material is not particularly limited, but is, for example, 30 to 97% by mass, preferably 40 to 95% by mass, and more preferably 45 to 90% by mass.

[0018] [Inorganic solid electrolyte] The specific form of the inorganic solid electrolyte is not particularly limited, and any inorganic solid electrolyte known in the art can be used as appropriate, but examples include sulfide solid electrolytes and oxide solid electrolytes. Among these, it is preferable to include a sulfide solid electrolyte because it exhibits excellent lithium ion conductivity, and a sulfide solid electrolyte is particularly preferable. Furthermore, the sulfide solid electrolyte preferably contains Li and M elements, and the above M element is a sulfide solid electrolyte containing at least one element selected from the group consisting of P, Si, Ge, Sn, Ti, Zr, Nb, Al, Sb, Br, Cl and I, and more preferably a sulfide solid electrolyte containing Li and P elements. Examples include LPS (Li2S-P2S5), Li6PS5X (where X is Cl, Br or I), and Li7P3S 11 Li 3.2 P 0.96 Examples of sulfide solid electrolytes include s and Li3PS4. These sulfide solid electrolytes are preferably used because they have excellent lithium ion conductivity.

[0019] The ionic conductivity of an inorganic solid electrolyte at room temperature (25°C) (for example, the Li ion conductivity) is, for example, 1 × 10⁻⁶. -5 Preferably, S / cm or higher, 1 × 10 -4 A value of S / cm or higher is more preferable. The ionic conductivity of inorganic solid electrolytes can be measured by the AC impedance method.

[0020] Examples of inorganic solid electrolyte shapes include spherical, ellipsoidal, and other particulate forms. When the inorganic solid electrolyte is particulate, its average particle diameter (D50) is not particularly limited, but is preferably 0.01 μm to 40 μm, and more preferably 0.1 μm to 10 μm. In this specification, the value of the average particle diameter (D50) can be measured by laser diffraction scattering.

[0021] The inorganic solid electrolyte content in the electrode material is, for example, 3 to 65% by mass, preferably 8 to 50% by mass, and more preferably 10 to 30% by mass.

[0022] [Organic solid electrolyte] Organic solid electrolytes essentially contain a polymer compound and an alkali metal salt. In an organic solid electrolyte, the entire amount of the alkali metal salt is dissolved in the polymer compound. That is, in an organic solid electrolyte, all of the alkali metal salt exists in a dissociated state within the polymer compound, and there are no undissolved alkali metal salts in the polymer compound. It may also be substantially composed of only the polymer compound and the alkali metal salt. In this specification, "X is substantially composed of only Y" means that the total content of Y exceeds 99% by mass (upper limit: 100% by mass), with the total mass of X being 100% by mass. Preferably, X is composed of Y (total content = 100% by mass). Whether or not the entire amount of alkali metal salt is dissolved in the polymer compound can be determined using a differential scanning calorimetry (DSC) device. That is, when the organic solid electrolyte is heated at a rate of 10°C / min, if no endothermic peak appears in the DSC curve (particularly in the region 100°C before and after the melting point of the alkali metal salt), then the entire amount of alkali metal salt is dissolved in the polymer compound.

[0023] (polymer compound) The polymer compound can be any conventionally known polymer compound as appropriate. The polymer compound is not particularly limited as long as it can dissolve the alkali metal salt. The polymer compound preferably contains at least one of a halogen atom, a hydroxyl group, an amino group, a carbonyl group, and a cyano group, more preferably a carbonyl group and / or a cyano group, even more preferably at least one of a carboxyl group, a carbamoyl group, an ester group, an amide group, a carbonate group, a carbamate group, and a cyano group, and particularly preferably a carbonate group and / or a cyano group. The polymer compound may be a homopolymer or a copolymer.

[0024] In one embodiment, the polymer compound may have at least one repeating unit represented by the following chemical formulas 1 to 8.

[0025] [ka]

[0026] Among the above Chemical Formulas 1 to 8, L 1 ~L 5 are each independently an alkylene group having 2 to 20 carbon atoms, R 1 and R 3 are each independently a hydrogen atom or a methyl group, R 2 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R 4 ~R 6 are each independently a hydrogen atom or a fluorine atom, * is a bonding point with other atoms.

[0027] Among the above Chemical Formulas 1 to 8, L 1 ~L 5 are each independently preferably an alkylene group having 2 to 10 carbon atoms, more preferably an alkylene group having 2 to 6 carbon atoms, and even more preferably a group selected from the group consisting of an ethylene group, a propylene group, a trimethylene group, and a tetramethylene group.

[0028] In one embodiment, the polymer compound may contain at least one of the repeating units represented by the above Chemical Formulas 1 to 8 in an amount of 30 to 100 mol% based on the repeating units constituting the polymer compound, preferably 50 to 100 mol%, and more preferably 70 to 100 mol%.

[0029] In one embodiment, the polymer compound preferably contains at least one of the repeating units represented by Chemical Formulas 3 to 5 and Chemical Formula 7, and more preferably contains at least one of the repeating units represented by Chemical Formulas 3 and Chemical Formula 7.

[0030] Examples of polymer compounds include those selected from the group consisting of polyethylene carbonate (PEC), polypropylene carbonate (PPC), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polymethacrylonitrile, and vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP). Furthermore, one polymer compound may be used alone, or two or more may be used in combination. The weight-average molecular weight of the polymer compound is not particularly limited, but for example, it is greater than 1,000 and less than 1,000,000. In this specification, the weight-average molecular weight of the polymer compound is the value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0031] (Alkali metal salts) Alkali metal salts refer to salts formed from alkali metal cations and anions. Examples of alkali metal cations include lithium cations, sodium cations, and potassium cations. When the secondary battery according to the present invention is a lithium secondary battery, the alkali metal salt is preferably a lithium salt. When it is a lithium salt, the lithium ion conductivity is further improved in the lithium secondary battery. A lithium salt is a salt composed of lithium ions and anions, and one with excellent solubility in polymer compounds is preferably selected. An example of a lithium salt is, for example, chemical formula 9:((C m F 2m+1 )SO2)((C n F 2n+1Examples include lithium sulfonylimide salts containing fluorine represented by )SO2)NLi (in chemical formula 9, m and n are each independently one integer from 0 to 4), lithium sulfonylimide salts containing fluorine represented by the following chemical formula 10, lithium sulfonylimide salts containing fluorine represented by the following chemical formula 11, lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), LiClO4 (lithium perchlorate), lithium hexafluoroarsenate (LiAsF6), lithium trifluoroacetate (CF3COOLi), lithium bis(oxalate)borate (LiB(C2O4)2), etc. In particular, it is preferable to include at least one of the lithium sulfonylimide salts containing fluorine represented by the above chemical formula 9 and lithium hexafluorophosphate (LiPF6), and lithium bis(fluorosulfonyl)imide (LiN(SO2F) 2、 It is more preferably at least one of the alkali metal salts (preferably lithium salts) (also referred to herein as "LiFSI"), lithium bis(trifluoromethanesulfonyl)imide (LiN(SO2CF3)2, also referred to herein as "LiTFSI"), and lithium hexafluorophosphate (LiPF6), even more preferably LiTFSI and / or lithium hexafluorophosphate (LiPF6), and particularly preferably LiTFSI. One alkali metal salt (preferably a lithium salt) may be used alone, or two or more may be used in combination.

[0032] [ka]

[0033] In the organic solid electrolyte, the entire amount of alkali metal salt is dissolved in the polymer compound at a concentration of 40 to 90% by mass. If the above concentration is less than 40% by mass, the ionic conductivity of the battery is insufficient. If the above concentration exceeds 90% by mass, the entire amount of alkali metal salt cannot dissolve in the polymer compound, resulting in undissolved residue, and thus ion mobility is not ensured. In the organic solid electrolyte, the entire amount of alkali metal salt is dissolved in the polymer compound at a concentration preferably of 45 to 90% by mass, more preferably of 50 to 90% by mass, even more preferably of 60 to 87% by mass, and particularly preferably of 77 to 87% by mass. When the concentration is within the above range, the ionic conductivity in the electrode active material layer is further improved.

[0034] The content of the organic solid electrolyte in the electrode material is, for example, 0.2 to 5% by mass, preferably 0.3 to 3% by mass, more preferably 0.4 to 3% by mass, and even more preferably 0.4 to 2% by mass.

[0035] In an electrode material according to one embodiment of the present invention, the coverage rate of the electrode active material with the organic solid electrolyte is 70% or more and 100% or less, preferably 80% or more and 100% or less, more preferably 90% or more and 100% or less, and particularly preferably 100%. Also, in an electrode according to one embodiment of the present invention, the coverage rate of the inorganic solid electrolyte with the organic solid electrolyte is 70% or more and 100% or less, preferably 80% or more and 100% or less, more preferably 90% or more and 100% or less, and particularly preferably 100%. In this specification, the coverage rate of particles in the electrode material with the organic solid electrolyte is adopted as a value measured and calculated as follows. That is, in visual observation by scanning electron microscope energy-dispersive X-ray spectroscopy (SEM-EDX method), the percentage of the surface of the particles present in the SEM image to which the organic solid electrolyte is attached is calculated (area of ​​the part of the particle surface in contact with the organic solid electrolyte / surface area of ​​the particle × 100 (%)), and the obtained value is taken as the coverage rate. In one embodiment, it is preferable that at least one of the electrode active material and the inorganic solid electrolyte forms a core-shell structure with the organic solid electrolyte, and it is particularly preferable that both the electrode active material and the inorganic solid electrolyte form a core-shell structure with the organic solid electrolyte.

[0036] [Method for manufacturing electrode materials] Electrode materials are preferably manufactured by mixing an electrode active material and an inorganic solid electrolyte with a solution containing an organic solid electrolyte and a solvent to obtain a mixture, and then removing the solvent from the mixture. This mixing step allows for efficient coating of the electrode active material and inorganic solid electrolyte, and also facilitates adjusting the thickness of the organic solid electrolyte coating to a preferred range. In the mixing step, it is preferable to mix only the electrode active material and inorganic solid electrolyte with a solution substantially composed only of the organic solid electrolyte and solvent.

[0037] Although the mechanism by which the electrode material according to the present invention can reduce the resistance of a battery is not fully understood, the following reason is presumed. That is, during charging and discharging of a battery, the electrode active material expands and contracts, and gaps may be created between the solids. Here, by coating both the electrode active material and the inorganic solid electrolyte with a flexible organic solid electrolyte, even if gaps are created between the solids due to the expansion and contraction of the electrode active material during charging and discharging, the organic solid electrolyte present in these gaps can ensure ionic conductivity between the solids. Furthermore, by controlling the alkali metal salt concentration in the organic solid electrolyte to a predetermined range, the ionic conductivity of the battery can be improved. It should be noted that the above mechanism is based on speculation, and its accuracy does not affect the technical scope of the present invention.

[0038] The electrode material may contain a binder and a conductive additive as needed. Examples of binders that can be used in the electrode material include polyvinylidene fluoride (PVDF) (including compounds in which hydrogen atoms are substituted with other halogen elements), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethylcellulose. In one embodiment of the present invention, the binder content in the electrode material may be 0% by mass or more and 1% by mass or less, preferably 0% by mass or more and 0.01% by mass or less, more preferably 0% by mass or more and 0.001% by mass or less, and particularly preferably 0% by mass (i.e., no binder).

[0039] The conductive additives included in the electrode material are not particularly limited, but for example, carbon such as carbon black (specifically, acetylene black, Ketjen black®, furnace black, channel black, thermal lamp black, etc.), carbon nanotubes, and carbon nanofibers may be used. These conductive additives may be used individually or in combination of two or more. The content of the conductive additive in the electrode material is not particularly limited, but is preferably, for example, 1% to 10% by mass, and preferably 1% to 5% by mass.

[0040] <Electrode> According to the present invention, an electrode having an electrode active material layer containing the aforementioned electrode material is also provided. When the electrode material contains a positive electrode active material as the electrode active material, a positive electrode having a positive electrode active material layer is provided. When the electrode material contains a negative electrode active material as the electrode active material, a negative electrode having a negative electrode active material layer is provided.

[0041] [Current collector] The current collectors (negative electrode current collector, positive electrode current collector) have the function of mediating the movement of electrons from the electrode active material layers (negative electrode active material layer, positive electrode active material layer). If the negative electrode active material layer and positive electrode active material layer, as described later, are themselves conductive and can perform the current collecting function, then it is not necessary to use a current collector as a separate component from these electrode active material layers. In such a configuration, the negative electrode active material layer, as described later, directly constitutes the negative electrode, and the positive electrode active material layer, as described later, directly constitutes the positive electrode. There are no particular restrictions on the material used to make up the current collector. Examples of materials that can be used include metals such as aluminum, nickel, iron, stainless steel, titanium, and copper, as well as conductive resins. There are also no particular restrictions on the thickness of the current collector, but one example is 10 to 100 μm.

[0042] [Cathode active material layer] The positive electrode active material layer in an electrode according to one embodiment of the present invention includes the aforementioned electrode material, where the electrode active material is the positive electrode active material. The positive electrode active material layer essentially contains the positive electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, and may optionally contain a binder and a conductive additive. These components are as described in the <Electrode Material> section above.

[0043] The thickness of the positive electrode active material layer is, for example, 0.1 to 1000 μm, and preferably 10 to 300 μm.

[0044] [Negative electrode active material layer] The negative electrode active material layer in an electrode according to one embodiment of the present invention comprises the aforementioned electrode material, wherein the electrode active material is the negative electrode active material. The negative electrode active material layer essentially contains the negative electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, and may optionally contain a binder and a conductive additive. These components are as described in the <Electrode Material> section above.

[0045] The thickness of the negative electrode active material layer is, for example, 0.1 to 1000 μm, preferably 10 to 300 μm.

[0046] The content of electrode active material in the electrode active material layer is, for example, 30 to 97% by mass, preferably 50 to 95% by mass, and more preferably 70 to 90% by mass. The content of inorganic solid electrolyte in the electrode active material layer is, for example, 3 to 65% by mass, preferably 8 to 50% by mass, and more preferably 10 to 30% by mass. The content of organic solid electrolyte in the electrode active material layer is, for example, 0.2 to 5% by mass, preferably 0.3 to 3% by mass, more preferably 0.4 to 3% by mass, and even more preferably 0.4 to 2% by mass. The content of binder in the electrode active material layer is, for example, 0 to 1% by mass or less, preferably 0 to 0.01% by mass, more preferably 0 to 0.001% by mass, and particularly preferably 0% by mass (i.e., no binder). The content of conductive additive in the electrode active material layer is, for example, 1% to 10% by mass, and preferably 1% to 5% by mass.

[0047] The contact area ratio of the electrode active material in the electrode with the organic solid electrolyte is 70% or more and 100% or less, preferably 80% or more and 100%, more preferably 90% or more and 100%, and particularly preferably 100%. Similarly, the contact area ratio of the inorganic solid electrolyte in the electrode with the organic solid electrolyte is 70% or more and 100% or less, preferably 80% or more and 100%, more preferably 90% or more and 100%, and particularly preferably 100%. In this specification, the contact area ratio (%) of the electrode active material and the inorganic solid electrolyte with the organic solid electrolyte is determined by the following measured and calculated values. Specifically, a cross-section of the electrode active material layer is obtained using a scanning electron microscope (SEM) to acquire an SEM image (observation magnification 10,000x, field of view containing approximately 10 positive electrode active materials). Subsequently, image analysis software (software name: Image Pro) is used to display all SEM images color-coded by component. Next, the percentage of the outer circumference of the electrode active material or inorganic solid electrolyte present in the SEM image that is in contact with the organic solid electrolyte is calculated (length of the outer circumference of the electrode active material or inorganic solid electrolyte in contact with the organic solid electrolyte / length of the outer circumference of the electrode active material or inorganic solid electrolyte × 100 (%)), and the obtained value is taken as the contact area ratio.

[0048] The electrode according to this embodiment is manufactured by obtaining an electrode material by the method described in the above-mentioned [Method for Manufacturing Electrode Material] and forming an electrode active material layer using the electrode material.

[0049] <Secondary battery> According to one embodiment of the present invention, a secondary battery is also provided, comprising a power generation element having a positive electrode having a positive electrode active material layer containing a positive electrode active material, a negative electrode having a negative electrode active material layer containing a negative electrode active material, and a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte, wherein at least one of the positive electrode and the negative electrode is the electrode described above.

[0050] The secondary battery according to this embodiment will be described below with reference to the attached drawings. The technical scope of the present invention should be determined based on the claims and is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. Also, the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.

[0051] Figure 1 is a schematic cross-sectional view showing the overall structure of a stacked (internal parallel connection type) all-solid-state secondary battery (hereinafter also simply referred to as "stacked secondary battery"), which is one embodiment of the present invention. By using a stacked design, the battery can be made compact and have a high capacity. In this specification, the stacked secondary battery shown in Figure 1 (hereinafter also simply referred to as "stacked battery") will be used as an example to explain the details.

[0052] As shown in Figure 1, the stacked battery 10a of this embodiment has a structure in which a flattened, roughly rectangular power generation element 21, on which the charge-discharge reaction actually takes place, is sealed inside a laminate film 29, which is the battery exterior material. Here, the power generation element 21 has a structure in which a positive electrode, a solid electrolyte layer 17, and a negative electrode are stacked. The positive electrode has a structure in which a positive electrode active material layer 15 containing positive electrode active material is arranged on both sides of a positive electrode current collector 11''. The negative electrode has a structure in which a negative electrode active material layer 13 containing negative electrode active material is arranged on both sides of a negative electrode current collector 11'. Specifically, the positive electrode, solid electrolyte layer, and negative electrode are stacked in this order such that one positive electrode active material layer 15 and the adjacent negative electrode active material layer 13 face each other via the solid electrolyte layer 17. As a result, adjacent positive electrode, solid electrolyte layer, and negative electrode This constitutes one single cell layer 19. Therefore, the stacked battery 10a shown in Figure 1 can also be said to have a configuration in which multiple single cell layers 19 are stacked and electrically connected in parallel. The negative electrode current collector 11' and the positive electrode current collector 11'' are each fitted with a negative electrode current collector plate 25 and a positive electrode current collector plate 27, which are electrically connected to the respective electrodes (negative and positive electrodes), and have a structure that leads out to the outside of the laminate film 29 by being sandwiched between the edges of the laminate film 29. The stacked battery 10a is subjected to restraining pressure in the stacking direction of the power generation elements 21 by a pressurizing member (not shown). Therefore, the volume of the power generation elements 21 is kept constant.

[0053] The main components of the secondary battery according to this embodiment will be described below.

[0054] [Positive and negative electrodes] The positive electrode may include a positive electrode other than the electrode described in the <Electrode> section above. For positive electrodes other than those described above, conventionally known positive electrodes may be used as appropriate.

[0055] Similarly, the negative electrode may include a negative electrode other than the one described in the <Electrode> section above, and conventionally known negative electrodes can be used as appropriate for negative electrodes other than those described above. An example of a negative electrode other than those described above is a so-called lithium deposition type secondary battery in which lithium metal is deposited on the negative electrode current collector as a negative electrode active material during the charging process. In this case, lithium metal may be used as the negative electrode active material in the negative electrode. In this case, the layer made of lithium metal deposited during the charging process becomes the negative electrode active material layer, so the thickness of the negative electrode active material layer increases as the charging process progresses and decreases as the discharge process progresses. The negative electrode active material layer does not need to be present during complete discharge, but in some cases, a negative electrode active material layer made of a certain amount of lithium metal may be placed during complete discharge. Furthermore, the thickness of the negative electrode active material layer (lithium metal layer) during complete charge is not particularly limited, but it is usually 0.1 to 1000 μm.

[0056] Both the positive and negative electrodes may include the electrodes described in the <Electrodes> section above, or only one of the positive or negative electrodes may include the electrodes described above. In one embodiment, it is preferable that the positive electrode includes the electrodes described above, and it is more preferable that the entire positive electrode is the electrodes described above.

[0057] [Solid electrolyte layer] The solid electrolyte layer is interposed between the negative electrode and the positive electrode and contains a solid electrolyte (usually as the main component). The solid electrolyte contained in the solid electrolyte layer may be the same as the inorganic solid electrolyte described in the [Inorganic Solid Electrolyte] section of the <Electrode Materials> above. The solid electrolyte content in the solid electrolyte layer is preferably 50 to 100% by mass, and more preferably 90 to 100% by mass.

[0058] The solid electrolyte layer may further contain a binder in addition to the solid electrolyte. The binder is not particularly limited, and known binders can be used as appropriate, for example, the binders described in the <Electrode Materials> section above can be similarly employed. The binder content in the solid electrolyte layer is not particularly limited, but is, for example, 1 to 10% by mass.

[0059] The thickness of the solid electrolyte layer is, for example, 0.1 to 1000 μm.

[0060] [Positive electrode current collector plate and negative electrode current collector plate] The materials constituting the current collector plates (25, 27) are not particularly limited, and known highly conductive materials conventionally used as current collector plates for secondary batteries can be used. Preferred materials for the current collector plates are metallic materials such as aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof. From the viewpoint of lightness, corrosion resistance, and high conductivity, aluminum and copper are more preferred, and aluminum is particularly preferred. The positive electrode current collector plate 27 and the negative electrode current collector plate 25 may be made of the same material or different materials.

[0061] [Positive lead and negative lead] Furthermore, although not shown in the diagram, the current collectors (11”, 11') and the current collector plates (27, 25) may be electrically connected via positive and negative leads. The materials used for the positive and negative leads can be the same as those used in known secondary batteries. It is preferable to cover the parts that are removed from the casing with heat-resistant insulating heat-shrink tubing or the like to prevent leakage current from coming into contact with peripheral equipment or wiring and affecting the product (for example, automotive parts, especially electronic equipment).

[0062] [Battery casing material] As the battery casing material, known metal can cases can be used, or, as shown in Figure 1, a bag-shaped case made of aluminum-containing laminate film 29 that can cover the power generation elements can be used. For example, a three-layer laminate film made by laminating PP, aluminum, and nylon in that order can be used, but there are no limitations to these. Laminate film is preferable from the viewpoint of being able to increase output and have excellent cooling performance, and can be suitably used for batteries in large equipment for EVs and HEVs. Furthermore, aluminum-containing laminate film is more preferable as the casing material because it allows for easy adjustment of the group pressure applied to the power generation elements from the outside.

[0063] The secondary battery according to this embodiment has a configuration in which multiple single cell layers are connected in parallel, resulting in high capacity and excellent cycle durability. Therefore, the secondary battery according to this embodiment is suitable for use as a power source for EVs and HEVs.

[0064] The secondary battery according to this embodiment may be all-solid-state or not. That is, the solid electrolyte layer may further contain a conventionally known liquid electrolyte. There are no particular restrictions on the amount of liquid electrolyte that may be contained in the solid electrolyte layer, but it is preferable that the amount is such that the shape of the solid electrolyte layer formed by the solid electrolyte is maintained and leakage of the liquid electrolyte does not occur. Furthermore, the secondary battery according to this embodiment is preferably a lithium secondary battery.

[0065] Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-mentioned embodiment and can be modified as appropriate based on the claims.

[0066] Furthermore, the following items are also included within the scope of the present invention: Item 1: An electrode material comprising an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, wherein the electrode active material and the inorganic solid electrolyte are coated with the organic solid electrolyte, the organic solid electrolyte comprises a polymer compound and an alkali metal salt, and the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 40 to 90% by mass; Item 2: The electrode material according to Item 1, wherein the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 45-90% by mass (preferably 50-90% by mass, more preferably 60-87% by mass, and even more preferably 77-87% by mass); Item 3: The electrode material according to item 1 or 2, wherein the content of the organic solid electrolyte in the electrode material is 0.3 to 3% by mass (preferably 0.4 to 3% by mass, more preferably 0.4 to 2% by mass); Item 4: An electrode material according to any one of items 1 to 3, wherein the weight-average molecular weight of the polymer compound is greater than 1,000 and less than 1,000,000; Item 5: The above polymer compound is an electrode material according to any one of items 1 to 4, comprising a carbonyl group and / or a cyano group; Item 6: The electrode material according to any one of items 1 to 5, wherein the alkali metal salt is a lithium salt; Item 7: The inorganic solid electrolyte is a sulfide solid electrolyte, as described in any of items 1 to 6; Item 8: The electrode material described in any of items 1 to 7, wherein the electrode active material is a positive electrode active material; Item 9: An electrode having an electrode active material layer containing the electrode material described in any of items 1 to 8; Item 10: The electrode according to item 9, wherein the contact area ratio of the electrode active material with the organic solid electrolyte is 70% or more and 100% or less, and the contact area ratio of the inorganic solid electrolyte with the organic solid electrolyte is 70% or more and 100% or less; Item 11: An electrode according to item 9 or 10, having an electrode active material layer comprising an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte, wherein the organic solid electrolyte comprises at least one polymer compound and at least one alkali metal salt, the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 40 to 90% by mass, the contact area ratio of the electrode active material with the organic solid electrolyte is 70% or more and 100% or less, and the contact area ratio of the inorganic solid electrolyte with the organic solid electrolyte is 70% or more and 100% or less; Item 12: A secondary battery comprising a power generation element having a positive electrode having a positive electrode active material layer containing a positive electrode active material, a negative electrode having a negative electrode active material layer containing a negative electrode active material, and a solid electrolyte layer interposed between the positive electrode and the negative electrode and containing a solid electrolyte, wherein at least one of the positive electrode and the negative electrode is an electrode according to any one of items 9 to 11; Item 13: A method for manufacturing an electrode according to any one of items 9 to 11, comprising: mixing the electrode active material and the inorganic solid electrolyte with a solution containing the organic solid electrolyte and a solvent to obtain a mixture; removing the solvent from the mixture to obtain an electrode material; and forming an electrode active material layer using the electrode material. [Examples]

[0067] The present invention will be described in more detail below with reference to examples. However, the technical scope of the present invention is not limited to the following examples. In the following, the operations were carried out in a glove box with a dew point of -68°C or lower. Furthermore, the instruments and equipment used in the glove box were thoroughly dried beforehand.

[0068] <Example of creating evaluation cells> [Example 1] (Fabrication of positive electrode material) 10.02 mg of polyethylene carbonate (labeled "PEC" in Table 1, manufactured by QPAC) as a polymer compound and 9.98 mg of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, manufactured by Kishida Chemical Co., Ltd.) as a lithium salt were weighed and added to 12 g of acetonitrile as a solvent. The resulting mixed solution was stirred at 45°C overnight to prepare an organic solid electrolyte-containing solution (polymer compound:lithium salt (mass ratio) = 50.1:49.9). NMC composite oxide (LiNi) was added to the prepared organic solid electrolyte-containing solution as a positive electrode active material. 0.8 Mn 0.1 Co 0.1 4.1 g of O2 (MSE, NCM811) and 0.73 g of a sulfide solid electrolyte (Li6PS5Cl, Ampcera) as an inorganic solid electrolyte were added, and the mixture was heated and stirred at 45°C overnight, after which it was allowed to cool to room temperature. The resulting solution was then transferred to a centrifuge tube and centrifuged at 13,000 rpm for 10 minutes, after which the supernatant was removed by decantation. The mixture from which the supernatant had been removed was then vacuum dried at 60°C for 24 hours to obtain an organic solid electrolyte / inorganic solid electrolyte / cathode active material composite. The content of the organic solid electrolyte in the obtained organic solid electrolyte / inorganic solid electrolyte / cathode active material composite was calculated by quantifying the amount of fluorine using combustion ion chromatography and the amount of carbon using a carbon-sulfur analyzer. As a result, the mass ratio of cathode active material:organic solid electrolyte:inorganic solid electrolyte was 82:0.4:14.6. 194 mg of the prepared organic solid electrolyte / inorganic solid electrolyte / cathode active material composite and 6 mg of carbon nanofiber (Showa Denko Corporation, VGCF) as a conductive additive were placed in an agate mortar and mixed for 30 minutes to obtain a powdered cathode material.

[0069] (Creation of evaluation cells) A cylindrical convex punch (10 mm in diameter) made of stainless steel was inserted into one side of a cylindrical tube jig made by Macol (10 mm inner diameter, 23 mm outer diameter, 20 mm height), and 80 mg of sulfide solid electrolyte (Ampcera, Li6PS5Cl) was placed in from the top of the cylindrical tube jig. Then, another cylindrical convex punch made of stainless steel was inserted to sandwich the sulfide solid electrolyte, and a solid electrolyte layer with a diameter of 10 mm and a thickness of approximately 0.6 mm was formed inside the cylindrical tube jig by pressing with a hydraulic press at a pressure of 75 MPa for 3 minutes. Next, the cylindrical convex punch inserted from the top (which also served as the positive electrode current collector) was temporarily removed, 20.4 mg of positive electrode material was placed on one side of the solid electrolyte layer inside the cylindrical tube, and the cylindrical convex punch was inserted again from the top. Next, the cylindrical convex punch (which also serves as the negative electrode current collector) inserted from below was temporarily removed, and an indium foil (manufactured by Nilaco, 0.02 mm thick, 10 mm in diameter) was placed on the other side of the solid electrolyte layer inside the cylindrical tube. The cylindrical convex punch was then inserted again from below. The positive electrode active material layer and the indium foil were pressed to the solid electrolyte layer by pressing at a pressure of 300 MPa for 3 minutes. The upper cylindrical convex punch was removed again, and a lithium foil (manufactured by Nilaco, 0.20 mm thick, 8 mm in diameter) and another indium foil (manufactured by Nilaco, 0.30 mm thick, 9 mm in diameter) were placed on top of the indium foil. The cylindrical convex punch was then inserted again, and the lithium-indium negative electrode was formed by pressing at a pressure of 100 MPa for 3 minutes. The cell constraint pressure was set to 0.5 MPa. In this manner, an evaluation cell was fabricated in which the positive electrode layer, solid electrolyte layer, and lithium-indium negative electrode were laminated.

[0070] [Example 2] An evaluation cell for this example was prepared in the same manner as in Example 1, except that the polymer compound:lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 38:62.

[0071] [Example 3] An evaluation cell for this example was prepared in the same manner as in Example 1, except that the ratio of polymer compound to lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 23.5:76.5.

[0072] [Example 4] An evaluation cell for this example was prepared in the same manner as in Example 1, except that the polymer compound:lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 17:83.

[0073] [Example 5] An evaluation cell for this example was prepared in the same manner as in Example 1, except that the ratio of polymer compound to lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 13.3:86.7.

[0074] [Example 6] The evaluation cell for this example was prepared in the same manner as in Example 1, except that the polymer compound:lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 10.9:89.1.

[0075] [Example 7] The evaluation cell for this example was prepared in the same manner as in Example 4, except that lithium hexafluorophosphate (LiPF6) was used as the lithium salt.

[0076] [Example 8] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the polymer compound used was polyacrylonitrile (PAN).

[0077] [Example 9] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the type of inorganic solid electrolyte used for the positive electrode material was Li2S-P2S5.

[0078] [Example 10] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the type of inorganic solid electrolyte for the positive electrode material was Li3YCl6.

[0079] [Example 11] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the positive electrode material was prepared so that the mass ratio of positive electrode active material:organic solid electrolyte:inorganic solid electrolyte was 82:1.2:13.8.

[0080] [Example 12] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the positive electrode material was prepared so that the mass ratio of positive electrode active material:organic solid electrolyte:inorganic solid electrolyte was 82:2:13.

[0081] [Example 13] The evaluation cell for this example was prepared in the same manner as in Example 4, except that the positive electrode material was prepared so that the mass ratio of positive electrode active material:organic solid electrolyte:inorganic solid electrolyte was 82:3:12.

[0082] [Example 14] (Fabrication of positive electrode material) 25.5 mg of polyethylene carbonate (PEC, QPAC) as a polymer compound and 124.5 mg of lithium bis(trifluoromethanesulfonyl)imide (Kishida Chemical Co., Ltd., LiTFSI) as a lithium salt were weighed and added to 10 g of acetonitrile as a solvent. The resulting mixed solution was stirred at 45°C overnight to prepare an organic solid electrolyte-containing solution (polymer compound:lithium salt (mass ratio) = 17:83). NMC composite oxide (LiNi) was added to the prepared organic solid electrolyte-containing solution as a positive electrode active material. 0.8 Mn 0.1 Co 0.1 4.1 g of O2 (NCM811, manufactured by MSE) was added, and the mixture was heated and stirred at 45°C for 24 hours, after which it was allowed to cool to room temperature. The supernatant was then removed, and the mixture was vacuum-dried at 60°C for 24 hours to obtain an organic solid electrolyte / cathode active material composite.

[0083] Separately from the above, 8.6 mg of polyethylene carbonate (PEC, QPAC) as a polymer compound and 41.8 mg of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, Kishida Chemical Co., Ltd.) as a lithium salt were weighed and added to 20 g of acetonitrile as a solvent. The resulting mixed solution was stirred at 45°C overnight to prepare an organic solid electrolyte-containing solution (polymer compound:lithium salt (mass ratio) = 17:83). 1.46 g of sulfide solid electrolyte (Li6PS5Cl, Ampcera) as an inorganic solid electrolyte was added to the prepared organic solid electrolyte-containing solution, and the mixture was heated and stirred at 45°C overnight for another day, after which it was allowed to cool to room temperature. After removing the supernatant, the mixture was vacuum-dried at 60°C for 24 hours to obtain an organic solid electrolyte / inorganic solid electrolyte composite.

[0084] The content of the organic solid electrolyte was calculated in the same manner as in Example 1 above. As a result, in the organic solid electrolyte / cathode active material composite, the mass ratio of the cathode active material to the organic solid electrolyte was 82:3, and in the organic solid electrolyte / inorganic solid electrolyte composite, the mass ratio of the organic solid electrolyte to the inorganic solid electrolyte was 0.4:11.6.

[0085] 170 mg of the obtained organic solid electrolyte / cathode active material composite, 24 mg of the organic solid electrolyte / inorganic solid electrolyte composite, and 6 mg of carbon nanofiber (VGCF, manufactured by Showa Denko Corporation) as a conductive additive were placed in an agate mortar and mixed for 30 minutes to obtain a powdered cathode material.

[0086] Subsequently, the evaluation cells for this example were prepared by performing the same procedure as described in Example 1 (Preparation of evaluation cells).

[0087] [Comparative Example 1] (Fabrication of positive electrode material) No organic solid electrolyte was added to the positive electrode material. Specifically, NMC composite oxide (LiNi) was used as the positive electrode active material. 0.8 Mn 0.1 Co 0.1A powdered cathode material was obtained by mixing 164 mg of O2 (manufactured by MSE, NCM811), 30 mg of a sulfide solid electrolyte (Li6PS5Cl, manufactured by Ampcera) as an inorganic solid electrolyte, and 6 mg of carbon nanofiber (manufactured by Showa Denko, VGCF) as a conductive additive in an agate mortar for 30 minutes.

[0088] Subsequently, the evaluation cells for this example were prepared by performing the same procedure as described in Example 1 (Preparation of evaluation cells).

[0089] [Comparative Example 2] (Fabrication of positive electrode material) The positive electrode active material was coated with an organic solid electrolyte. Polyethylene oxide (PEO) was used as the polymer compound. Specifically, 15.1 mg of polyethylene oxide (PEO) as the polymer compound and 4.9 mg of lithium bis(trifluoromethanesulfonyl)imide (Kishida Chemical Co., Ltd., LiTFSI) as the lithium salt were weighed and added to 10 g of acetonitrile as the solvent. The resulting mixed solution was stirred at 45°C overnight to prepare an organic solid electrolyte-containing solution (polymer compound:lithium salt (mass ratio) = 75.4:24.6). To the prepared organic solid electrolyte-containing solution, an NMC composite oxide (LiNi) was added as the positive electrode active material. 0.8 Mn 0.1 Co 0.14.1 g of O2 (manufactured by MSE, NCM811) was added, and the mixture was heated and stirred at 45°C for 24 hours, after which it was allowed to cool to room temperature. The supernatant was then removed, and the mixture was vacuum-dried at 60°C for 24 hours to obtain an organic solid electrolyte / cathode active material composite. The content of the organic solid electrolyte was calculated in the same manner as in Example 1 above. As a result, the mass ratio of the cathode active material to the organic solid electrolyte in the organic solid electrolyte / cathode active material composite was 82:0.4. 164.8 mg of the obtained organic solid electrolyte / cathode active material composite, 29.2 mg of sulfide solid electrolyte (Li6PS5Cl, manufactured by Ampcera) as an inorganic solid electrolyte, and 6 mg of carbon nanofiber (Showa Denko, VGCF) as a conductive additive were placed in an agate mortar and mixed for 30 minutes to obtain a powdered cathode material.

[0090] Subsequently, the evaluation cells for this example were prepared by performing the same procedure as described in Example 1 (Preparation of evaluation cells).

[0091] [Comparative Example 3] The evaluation cell for this comparative example was prepared in the same manner as in Example 1, except that the polymer compound used was polyethylene oxide (PEO).

[0092] [Comparative Example 4] (Fabrication of positive electrode material) 6.8 mg of polyethylene carbonate (PEC, QPAC) as a polymer compound and 33.2 mg of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, Kishida Chemical Co., Ltd.) as a lithium salt were weighed and added to 20 g of acetonitrile as a solvent. The resulting mixed solution was stirred at 45°C overnight to prepare an organic solid electrolyte-containing solution (polymer compound:lithium salt (mass ratio) = 17:83). 1.46 g of sulfide solid electrolyte (Li6PS5Cl, Ampcera) as an inorganic solid electrolyte was added to the prepared organic solid electrolyte-containing solution, and the mixture was heated and stirred at 45°C overnight, after which it was allowed to cool to room temperature. The supernatant was then removed, and the mixture was vacuum-dried at 60°C for 24 hours to obtain an organic solid electrolyte / inorganic solid electrolyte composite. The content of the organic solid electrolyte was calculated in the same manner as in Example 1 above. As a result, in the organic solid electrolyte / inorganic solid electrolyte composite, the mass ratio of organic solid electrolyte to inorganic solid electrolyte was 0.4:14.6. Next, the NMC composite oxide (LiNi) used as the positive electrode active material... 0.8 Mn 0.1 Co 0.1 A powdered cathode material was obtained by mixing 164 mg of O2 (manufactured by MSE, NCM811), 30 mg of the obtained organic solid electrolyte / inorganic solid electrolyte composite, and 6 mg of carbon nanofiber (manufactured by Showa Denko, VGCF) as a conductive additive in an agate mortar for 30 minutes.

[0093] Subsequently, the evaluation cells for this example were prepared by performing the same procedure as described in Example 1 (Preparation of evaluation cells).

[0094] [Comparative Example 5] An evaluation cell for this comparative example was prepared in the same manner as in Example 1, except that the ratio of polymer compound to lithium salt (mass ratio) in the organic solid electrolyte-containing solution was 75.4:24.6.

[0095] [Comparative Example 6] An evaluation cell for this comparative example was prepared in the same manner as in Example 1, except that the polymer compound:lithium salt (mass ratio) in the organic solid electrolyte-containing solution was set to 7:93.

[0096] <Measurement of DC Resistance (DCR)> The DC resistance (DCR) of the evaluation cells prepared in the above examples and comparative examples was measured using the following method. A charge / discharge test apparatus (HJ-SD8, manufactured by Hokuto Denko Co., Ltd.) was used for the measurement. First, the battery was placed in a constant temperature bath set to 60°C, and after the cell temperature stabilized, 0.2 mA / cm² was measured. 2 Constant current constant voltage charging up to 3.68V with a current density of 0.04mA / cm². 2 The charge-discharge cycle was performed using the specified settings, followed by a constant current discharge down to 1.88V at the same current density. After repeating this charge-discharge cycle 10 times, the resulting discharge capacity was defined as the battery's rated capacity, and the capacity per unit mass of the positive electrode active material (mAh / g) was calculated from the mass of the positive electrode active material contained in the positive electrode. Next, the capacity was reduced to 50% of the calculated capacity (SOC 50%) by 0.2mA / cm². 2 Constant current discharge was performed at the current density of 6 mA / cm². After a 30-minute pause, the current density was reduced to 6 mA / cm². 2 The discharge was performed for 10 seconds at the specified discharge rate, and the DC resistance (DCR) was calculated according to Ohm's law from the voltage drop and current value during that time. The results are shown in Table 1 below.

[0097] [Table 1]

[0098] From the results in Table 1, it was found that the battery resistance was reduced in the evaluation cells of Examples 1 to 14, which included the electrode according to this embodiment as the positive electrode. Furthermore, scanning electron microscopy (SEM) was used to calculate the coverage rate (%) of the positive electrode active material and inorganic solid electrolyte by the organic solid electrolyte for each of the positive electrode active material and inorganic solid electrolyte layers of Examples 1 to 14, and it was confirmed that the coverage rate was 70% or higher in all examples. In addition, differential scanning calorimetry (DSC) was performed on the organic solid electrolytes of Examples 6 to 8 and Comparative Example 6. First, the organic solid electrolyte-containing solutions prepared above were dried on a glass plate to obtain the organic solid electrolytes. The obtained organic solid electrolytes were heated at a rate of 10°C / min and differential scanning calorimetry was performed. As a result, no endothermic peaks appeared in the DSC curves of the organic solid electrolytes of Examples 6 to 8. On the other hand, an endothermic peak was observed in the DSC curve of the organic solid electrolyte of Comparative Example 6. From these results, it was found that in the organic solid electrolytes of Examples 6 to 8, the alkali metal salts were completely dissolved in the polymer compound. In contrast, in the organic solid electrolyte of Comparative Example 6, it was found that the alkali metal salt was not completely dissolved in the polymer compound, and undissolved residue remained. [Explanation of symbols]

[0099] 10A stacked secondary battery, 11' negative electrode current collector, 11” positive electrode current collector, 13 negative electrode active material layer, 15 positive electrode active material layer, 17 solid electrolyte layer, 19 single cell layers, 21 Power generation elements, 25 Negative electrode current collector plate, 27 Positive electrode current collector plate, 29. Laminating film.

Claims

1. It comprises an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte. The electrode active material and the inorganic solid electrolyte are coated with the organic solid electrolyte. The organic solid electrolyte comprises a polymer compound and an alkali metal salt. An electrode material in which the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 40 to 90% by mass.

2. The electrode material according to claim 1, wherein the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 50 to 90% by mass.

3. The electrode material according to claim 2, wherein the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 60 to 87% by mass.

4. The electrode material according to claim 3, wherein the entire amount of the alkali metal salt in the organic solid electrolyte is dissolved in the polymer compound at a concentration of 77 to 87% by mass.

5. The electrode material according to claim 1, wherein the content of the organic solid electrolyte in the electrode material is 0.3 to 3% by mass.

6. The electrode material according to claim 5, wherein the content of the organic solid electrolyte in the electrode material is 0.4 to 3% by mass.

7. The electrode material according to claim 6, wherein the content of the organic solid electrolyte in the electrode material is 0.4 to 2% by mass.

8. The electrode material according to claim 1, wherein the weight-average molecular weight of the polymer compound is greater than 1,000 and less than 1,000,000.

9. The electrode material according to claim 1, wherein the polymer compound comprises a carbonyl group and / or a cyano group.

10. The electrode material according to claim 1, wherein the alkali metal salt is a lithium salt.

11. The electrode material according to claim 1, wherein the inorganic solid electrolyte is a sulfide solid electrolyte.

12. The electrode material according to claim 1, wherein the electrode active material is a positive electrode active material.

13. An electrode having an electrode active material layer containing the electrode material described in claim 1.

14. The contact area ratio of the electrode active material with the organic solid electrolyte is 70% or more and 100% or less. The electrode according to claim 13, wherein the contact area ratio of the inorganic solid electrolyte with the organic solid electrolyte is 70% or more and 100% or less.

15. The electrode has an electrode active material layer containing an electrode active material, an inorganic solid electrolyte, and an organic solid electrolyte. The organic solid electrolyte comprises at least one polymer compound and at least one alkali metal salt. In the aforementioned organic solid electrolyte, the entire amount of the alkali metal salt is dissolved in the polymer compound at a concentration of 40 to 90% by mass. The contact area ratio of the electrode active material with the organic solid electrolyte is 70% or more and 100% or less. An electrode in which the contact area ratio of the inorganic solid electrolyte with the organic solid electrolyte is 70% or more and 100% or less.

16. A positive electrode having a positive electrode active material layer containing positive electrode active material, A negative electrode having a negative electrode active material layer containing a negative electrode active material, A solid electrolyte layer containing a solid electrolyte is interposed between the positive electrode and the negative electrode, Equipped with a power generation element having, A secondary battery in which at least one of the positive electrode and the negative electrode is the electrode described in claim 13 or 15.

17. A method for manufacturing an electrode according to claim 13 or 15, A mixture is obtained by mixing the electrode active material and the inorganic solid electrolyte with a solution containing the organic solid electrolyte and a solvent. To remove the solvent from the mixture to obtain an electrode material, and A method for manufacturing an electrode, comprising forming an electrode active material layer using the electrode material.

Images