Electrode body and energy storage element

Abstract

To provide an electrode body in which an active material layer has a relatively low charge transfer resistance, and a power storage element having the electrode body.SOLUTION: An electrode body includes an active material layer including an active material and a solid electrolyte, the active material layer further includes an additive, the additive includes a first structural unit in which a hydrocarbon group and an ether bond are alternately repeated, and a second structural unit in which a hydrocarbon group and an ester bond are alternately repeated. A power storage element includes the electrode body described above.SELECTED DRAWING: Figure 1

Description

[Technical Field] 【0001】 The present invention relates to an electrode body and an energy storage element equipped with the electrode body. [Background technology] 【0002】 Patent Document 1 describes an all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is formed of a solid electrolyte composition, wherein the solid electrolyte composition comprises an inorganic solid electrolyte having conductivity for ions of metal elements belonging to Group 1 or Group 2 of the periodic table, and a polymer binder, wherein the polymer binder contains a branched polymer having three or more polymerization initiator residues of polymer molecules at the ends of the polymer molecules. [Prior art documents] [Patent Documents] 【0003】 [Patent Document 1] Japanese Patent Publication No. 2017-130264 [Overview of the Initiative] [Problems that the invention aims to solve] 【0004】 One object of the present invention is to provide an electrode body having relatively low charge transfer resistance in the active material layer, and an energy storage element equipped with the electrode body. [Means for solving the problem] 【0005】 An electrode body according to one aspect of the present invention comprises an active material layer containing an active material and a solid electrolyte, wherein the active material layer further contains an additive, and the additive contains a first structural unit in which hydrocarbon groups and ether bonds are alternately repeated, and a second structural unit in which hydrocarbon groups and ester bonds are alternately repeated. 【0006】 A power storage element according to another aspect of the present invention comprises the electrode body described above. 【Advantages of the Invention】 【0007】 In the electrode body according to one aspect of the present invention, the charge transfer resistance of the active material layer is relatively low. In the energy storage element according to another aspect of the present invention, the charge transfer resistance of the active material layer is relatively low. 【Brief Description of the Drawings】 【0008】 [Figure 1] FIG. 1 is a perspective view of the energy storage element according to the present embodiment. [Figure 2] FIG. 2 is a perspective view of the structural unit accommodated in the energy storage element of FIG. 1. [Figure 3] FIG. 3 is a schematic cross-sectional view of the electrode body constituting the energy storage element according to the present embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of the state in the production of the positive electrode active material layer. [Figure 5] FIG. 5 is a schematic diagram showing an example of the state in the production of the solid electrolyte layer. [Figure 6] FIG. 6 is a schematic view of an energy storage device including a plurality of energy storage elements according to the present embodiment. 【Modes for Carrying Out the Invention】 【0009】 The outline of the electrode body 2 and the energy storage element 1 disclosed by this specification will be described. 【0010】 The electrode body according to one aspect of the present invention includes an active material layer containing an active material and a solid electrolyte, the active material layer further contains an additive, and the additive contains a first structural unit in which a hydrocarbon group and an ether bond are alternately repeated, and a second structural unit in which a hydrocarbon group and an ester bond are alternately repeated. 【0011】 According to one aspect of the present invention described above, the charge transfer resistance of the active material layer can be made relatively low. 【0012】 Here, the additive contains a copolymer having the first structural unit and the second structural unit in its molecule, and the copolymer may be a block copolymer in which the first structural unit and the second structural unit are arranged along the main chain. 【0013】 This electrode structure allows for a lower charge transfer resistance in the active material layer. 【0014】 Furthermore, the number-average molecular weight of the copolymer may be 2,000 or more and 20,000 or less. 【0015】 This electrode structure allows for a lower charge transfer resistance in the active material layer. 【0016】 Furthermore, the copolymer may be represented by the following general formula (1). In general formula (1), R1 is a saturated hydrocarbon group having 1 to 4 carbon atoms, R2' and R2'' are each independently saturated hydrocarbon groups having 4 to 20 carbon atoms, A and B are each independently alkyl groups, hydrogen, or other monovalent characteristic groups, m, n1, and n2 are each independently positive integers, and the ratio of m to the sum of n1 and n2 is 0.8 to 8.0. [ka] 【0017】 This electrode structure allows for a lower charge transfer resistance in the active material layer. 【0018】 Furthermore, the copolymer may be a nonionic copolymer having the first structural unit and the second structural unit in its molecule. 【0019】 This electrode structure allows for a lower charge transfer resistance in the active material layer. 【0020】 A storage element according to another aspect of the present invention comprises the above-described electrode body. Therefore, in the storage element according to another aspect of the present invention, the charge transfer resistance of the active material layer can be made relatively low. 【0021】 The configuration of the electrode body 2, the energy storage element 1, the energy storage device 100, and other embodiments according to one embodiment of the present invention will be described in detail. Note that the names of the components (each element) used in each embodiment may differ from the names of the components (each element) used in the background art. 【0022】 <Configuration of energy storage element> As shown in Figures 1 to 3, an energy storage element 1 according to one embodiment of the present invention comprises an electrode body 2 having a positive electrode 40, a negative electrode 50, and a solid electrolyte layer 60, and a container 3 that houses the electrode body 2. Since the energy storage element 1 according to this embodiment does not substantially contain an electrolyte, it may hereinafter be referred to as an "all-solid-state energy storage element". In this embodiment, the electrode body 2 is a laminated electrode body in which the positive electrode 40, the negative electrode 50, and the solid electrolyte layer 60 are stacked. The container 3 houses the electrode body 2 inside by sandwiching it from both sides with two sheet-like materials. In other words, the container 3 is a flat-shaped so-called pouch container. The positive electrode 40 has a positive electrode active material layer 42 containing a solid electrolyte and a positive electrode active material, and the negative electrode 50 has a negative electrode active material layer 52 containing a solid electrolyte and a negative electrode active material. The solid electrolyte layer 60 is disposed between the positive electrode 40 and the negative electrode 50 and mainly contains a solid electrolyte. As an example of an all-solid-state energy storage device, we will describe an all-solid-state lithium-ion secondary battery (hereinafter also simply referred to as a "secondary battery"). 【0023】 More specifically, as shown in Figures 1 to 3, the energy storage element 1 of this embodiment comprises a laminated electrode body 2 in which a positive electrode 40 and a negative electrode 50 are laminated via a solid electrolyte layer 60, the above-mentioned container 3 for housing the electrode body 2, and two external terminals (positive electrode terminal 4 and negative electrode terminal 5). The positive electrode terminal 4 is formed by a tab portion extending outward from a part of the positive electrode base material 41 (described later) of the positive electrode 40. Similarly, the negative electrode terminal 5 is formed by a tab portion extending outward from a part of the negative electrode base material 51 (described later) of the negative electrode 50. The energy storage element 1 is configured such that electricity flows between the electrode body 2 and any external device via the positive terminal 4 and the negative terminal 5 during charging and discharging. In the energy storage element 1 of this embodiment, one electrode body 2 is housed in a container 3, and the electrode body 2 is configured to undergo a charging and discharging reaction. Furthermore, it is preferable that the container 3 is subjected to a compressive force in the thickness direction, from the outside inward. This further reduces the interfacial resistance between the positive electrode 40 and the negative electrode 50 and the solid electrolyte layer 60. Note that the electrode body 2 housed in the container 3 may be one or multiple. 【0024】 The electrode body 2 is constructed by stacking a rectangular sheet-shaped positive electrode 40 and a rectangular sheet-shaped negative electrode 50 via a solid electrolyte layer 60. As shown in Figure 3, the solid electrolyte layer 60 is arranged to electrically insulate the positive electrode 40 and the negative electrode 50. The solid electrolyte layer 60 does not contain either the positive electrode active material or the negative electrode active material. In this embodiment, both the electrode body 2 and the container 3 have a flattened shape. The electrode body 2 is placed inside the container 3 such that the stacking direction of the electrodes in the electrode body 2 is the same as the thickness direction of the container 3. 【0025】 In the electrode body 2 of this embodiment, at least one of the positive electrode active material layer 42 of the positive electrode 40, the negative electrode active material layer 52 of the negative electrode 50, and the solid electrolyte layer 60 contains a solid electrolyte. More specifically, in this embodiment, at least one of the positive electrode active material layer 42, the negative electrode active material layer 52, and the solid electrolyte layer 60 contains solid electrolyte particles. In addition, at least one of the positive electrode active material layer 42 and the negative electrode active material layer 52 contains an additive which will be described in detail later. 【0026】 (positive electrode) The positive electrode 40 has a positive electrode substrate 41 and a positive electrode active material layer 42 that is superimposed on the positive electrode substrate 41 either directly or via a predetermined layer. In this embodiment, the positive electrode substrate 41 and the positive electrode active material layer 42 are directly superimposed on the positive electrode 40. Also in this embodiment, the positive electrode active material layer 42 is superimposed on one side of the positive electrode substrate 41. The positive electrode active material layer 42 and the negative electrode active material layer 52 undergo a charge-discharge reaction with each other. 【0027】 The positive electrode substrate 41 is conductive. Whether or not it is conductive is determined by the volume resistivity measured in accordance with JIS-H-0505 (1975) when it is 10 7 The determination is made using Ω·cm as the threshold. As the material of the positive electrode substrate 41, metals such as aluminum, titanium, tantalum, and stainless steel, or alloys thereof, can be used. Among these, aluminum or aluminum alloys are preferred from the viewpoint of high potential resistance, high conductivity, and cost. Examples of positive electrode substrates 41 include foil and vapor-deposited films, with foil being preferred from the viewpoint of cost. Therefore, aluminum foil or aluminum alloy foil is preferred as the positive electrode substrate 41. Examples of aluminum or aluminum alloys include A1085 and A3003 as specified in JIS-H-4000 (2014). 【0028】 The average thickness of the positive electrode substrate 41 is preferably 1 μm or more and 50 μm or less, more preferably 30 μm or less, and even more preferably 15 μm or less. By setting the average thickness of the positive electrode substrate 41 within the above range, it is possible to increase the strength of the positive electrode substrate 41 while increasing the energy density per unit volume of the secondary battery. 【0029】 In this embodiment, the positive electrode active material layer 42 includes a positive electrode active material, a solid electrolyte (described in detail later), and additives (described in detail later). The positive electrode active material layer 42 preferably includes a binder. The positive electrode active material layer 42 optionally includes optional components such as a conductive agent and a thickener. 【0030】 The positive electrode active material can be appropriately selected from known positive electrode active materials. For lithium-ion secondary batteries, materials capable of intercalating and releasing lithium ions are typically used as positive electrode active materials. Examples of positive electrode active materials include lithium transition metal composite oxides having an α-NaFeO2 crystal structure, lithium transition metal composite oxides having a spinel crystal structure, polyanionic compounds, chalcogen compounds, and sulfur. Examples of lithium transition metal composite oxides having an α-NaFeO2 crystal structure include Li[Li x Ni (1-x)O2(0≦x<0.5), Li[Li x Ni γ Co (1-x-γ) O2(0≦x<0.5, 0<γ<1), Li[Li x Co (1-x) O2(0≦x<0.5), Li[LiNiMn (1-x-γ) O2(0≦x<0.5, 0<γ<1), Li[Li x Ni γ Mn β Co (1-x-γ-β) O2(0≦x<0.5, 0<γ, 0<β, 0.5<γ + β<1), Li[Li x Ni γ Co β Al (1-x-γ-β) O2(0≦x<0.5, 0<γ, 0<β, 0.5<γ + β<1), etc. are included. As the lithium transition metal composite oxide having a spinel crystal structure, Li x Mn2O4, Li x Ni γ Mn (2-γ) O4, etc. are included. As the polyanion compound, LiFePO4, LiMnPO4, LiNiPO4, LiCoPO4, Li3V2(PO4)3, Li2MnSiO4, Li2CoPO4F, etc. are included. As the chalcogen compound, titanium disulfide, molybdenum disulfide, iron sulfide, cobalt sulfide, copper sulfide, nickel sulfide, copper chalcogenide, etc. are included. In addition, sulfur, bismuth oxide, bismuth lead acid, copper oxide, vanadium oxide, etc. can also be used as the positive electrode active material. Atoms or polyanions in these materials may be partially substituted with atoms or anion species composed of other elements. These materials may have their surfaces coated with other materials. In the positive electrode active material layer 42, one of these materials may be used alone, or two or more of them may be mixed and used. As the positive electrode active material, it is preferable to select a material coated with a coating layer containing a material such as a lithium ion conductive oxide. As the lithium ion conductive oxide, LiNbO3, Li2WO4, Li4Ti5O 12Examples include Li3PO4, etc. Among these, LiNbO3 is preferred. The coating layer may cover the entire surface of the positive electrode active material, or it may partially cover the surface. 【0031】 The positive electrode active material is usually in particulate form. The average particle diameter of the positive electrode active material is preferably, for example, 0.1 μm or more and 20 μm or less. Having an average particle diameter of the positive electrode active material above the lower limit above makes the manufacturing or handling of the positive electrode active material easier. Having an average particle diameter of the positive electrode active material below the upper limit above improves the electronic conductivity of the positive electrode active material layer 42. When a composite of the positive electrode active material and other materials is used (for example, when the surface of the positive electrode active material is coated with a coating layer), the average particle diameter of the composite is taken as the average particle diameter of the positive electrode active material. "Average particle diameter" means the value at which the volume-based integrated distribution calculated in accordance with JIS-Z-8819-2 (2001), based on the particle size distribution measured by laser diffraction / scattering method on a dilution of particles diluted with a solvent, in accordance with JIS-Z-8825 (2013), becomes 50%. 【0032】 To obtain a positive electrode active material powder with a predetermined particle size, grinders and classifiers are used. Examples of grinding methods include using a mortar and pestle, ball mill, sand mill, vibrating ball mill, planetary ball mill, jet mill, counter jet mill, swirling airflow jet mill, or sieve. Wet grinding, which involves the coexistence of water or an organic solvent such as hexane, can also be used during grinding. For classification, sieves and air classifiers are used as needed, both dry and wet. 【0033】 The content of the positive electrode active material in the positive electrode active material layer 42 is preferably 10% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 80% by mass or less. By having the content of the positive electrode active material within the above range, it is possible to achieve both a high energy density in the positive electrode active material layer 42 and relatively simple manufacturing of the positive electrode active material layer 42. 【0034】 The positive electrode active material layer 42 contains a solid electrolyte, which will be described in detail later. The solid electrolyte may be, for example, an amorphous lump or particulate of a specific shape. The solid electrolyte is appropriately selected from among the solid electrolytes exemplified in the description of the solid electrolyte layer 60, which will be described in detail later. The solid electrolyte contained in the positive electrode active material layer 42 may be the same type as the solid electrolyte contained in the solid electrolyte layer 60, or it may be a different type. The solid electrolyte content in the positive electrode active material layer 42 is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 15% by mass or more and 70% by mass or less. By having the solid electrolyte content in the positive electrode active material layer 42 within the above range, the energy storage element can have a relatively large electrical capacity. The positive electrode active material layer 42 may contain multiple different types of solid electrolytes. 【0035】 The positive electrode active material layer 42 of this embodiment contains an additive. This additive contains a first structural unit in which hydrocarbon groups and ether bonds are alternately repeated, and a second structural unit in which hydrocarbon groups and ester bonds are alternately repeated. This additive is contained in at least one of the positive electrode active material layer 42 and the negative electrode active material layer 52 (described in detail later). 【0036】 The additive may include, for example, a copolymer having both the first structural unit and the second structural unit in its molecule, or a polymer blend which is a mixture of a polymer having the first structural unit and a polymer having the second structural unit. The additive may also include, for example, a polymer blend in which a polymer having the first structural unit and a polymer having the second structural unit interpenetrate each other's molecules to form a three-dimensional interpenetrating polymer network (IPN) structure. 【0037】 The above-described first structural unit has a molecular structure in which each hydrocarbon group is positioned between two ether bonds. In other words, the above-described first structural unit has a molecular structure in which two hydrocarbon groups are bonded to one ether bond. The hydrocarbon groups in the above-described first structural unit may be saturated hydrocarbon groups or unsaturated hydrocarbon groups. Furthermore, such hydrocarbon groups may be linear hydrocarbon groups, branched hydrocarbon groups, or aromatic or alicyclic hydrocarbon groups. Furthermore, the number of carbon atoms in each of these hydrocarbon groups may be between 1 and 4. Each hydrocarbon group in the above-mentioned first structural unit is preferably a saturated linear hydrocarbon group having 2 or 3 carbon atoms. The saturated linear hydrocarbon group in the above-mentioned first structural unit may be a saturated linear hydrocarbon group or a saturated branched hydrocarbon group, but it is preferably a saturated linear hydrocarbon group. 【0038】 The above-described second structural unit has a molecular structure in which each hydrocarbon group is positioned between two ester bonds. In other words, the above-described second structural unit has a molecular structure in which two hydrocarbon groups are bonded to one ester bond. The hydrocarbon groups in the above-described second structural unit may be saturated hydrocarbon groups or unsaturated hydrocarbon groups. Furthermore, such hydrocarbon groups may be linear hydrocarbon groups, branched hydrocarbon groups, or aromatic or alicyclic hydrocarbon groups. 【0039】 In this embodiment, the number of carbon atoms in each hydrocarbon group in the second structural unit is greater than the number of carbon atoms in each hydrocarbon group in the first structural unit. Furthermore, the number of carbon atoms in each hydrocarbon group in the second structural unit may be 4 or more, 5 or more, 6 or more, 7 or more, or 8 or more. In addition, the number of carbon atoms in each hydrocarbon group may be 20 or less, or 18 or less. Each hydrocarbon group in the above-mentioned second structural unit is preferably a saturated chain hydrocarbon group having 1 to 20 carbon atoms, and more preferably a saturated chain hydrocarbon group having 8 to 20 carbon atoms. The saturated chain hydrocarbon group in the above-mentioned second structural unit may be a saturated linear hydrocarbon group or a saturated branched hydrocarbon group, but it is preferable that it be a saturated branched hydrocarbon group. 【0040】 The additive preferably contains a copolymer having the above-mentioned first structural unit and the above-mentioned second structural unit in its molecule. Examples of this type of copolymer include a copolymer in which the first structural unit is arranged along the main chain and the second structural unit is arranged in the side chain, a copolymer in which the second structural unit is arranged along the main chain and the first structural unit is arranged in the side chain, or a block copolymer in which the first structural unit and the second structural unit are arranged along the main chain. 【0041】 The main chain of the copolymer described above is a molecular chain containing structural units in which at least one of ester bonds and ether bonds and hydrocarbon groups are alternately repeated. In the main chain of the copolymer described above, hydrocarbon groups may be positioned between ester bonds, or between ether bonds. As a general rule, the main chain of the copolymer is defined as a sequence of covalent bonds in which ester bonds and hydrocarbon groups alternate, or a sequence of covalent bonds in which ether bonds and hydrocarbon groups alternate. However, if there are at least two sequences of covalent bonds that could form the main chain that are separated from each other within the copolymer molecule, or if the main chain defined as described above is crosslinked with another main chain via side chains, and the main chain cannot necessarily be determined as a single entity, then the sequence of covalent bonds formed when the copolymer is synthesized from monomers, etc., is defined as the main chain. 【0042】 The additive preferably contains a block copolymer in which the first structural unit and the second structural unit are arranged along the main chain within the molecule. This type of block copolymer may be a triblock copolymer in which the number of bonds between the first and second structural units in the molecule is 2, or a tetrablock copolymer in which the number of bonds between the first and second structural units in the molecule is 3. By including the above-mentioned block copolymer as an additive, the charge transfer resistance of the positive electrode active material layer 42 can be further reduced. 【0043】 The block copolymer described above may be a triblock copolymer in which second structural units are arranged on both sides of a first structural unit along the main chain, or a triblock copolymer in which first structural units are arranged on both sides of a second structural unit. 【0044】 The polymer contained in the additive is preferably a copolymer represented by the following general formula (1). More specifically, the polymer contained in the additive is preferably a triblock copolymer in which second structural units are arranged on both sides of a first structural unit along the main chain, as represented by the following general formula (1). However, in general formula (1), R1 is a saturated hydrocarbon group having 1 to 4 carbon atoms, R2' and R2'' are each independently saturated hydrocarbon groups having 1 to 20 carbon atoms, A and B are each independently alkyl groups, hydrogen, or other monovalent characteristic groups, m, n1, and n2 are each independently positive integers, and the ratio of m to the sum of n1 and n2 is 0.8 to 8.0. In this embodiment, it is preferable that the number of carbon atoms in R2' and R2'' is greater than the number of carbon atoms in R1. [ka] 【0045】 In the above general formula (1), R1 is preferably a saturated hydrocarbon group having 2 or 3 carbon atoms. R2' and R2'' are each independently preferably a saturated branched hydrocarbon group having 4 to 20 carbon atoms, more preferably a saturated branched hydrocarbon group having 5 to 20 carbon atoms, even more preferably a saturated branched hydrocarbon group having 6 to 20 carbon atoms, even more preferably a saturated branched hydrocarbon group having 7 to 20 carbon atoms, and particularly preferably a saturated branched hydrocarbon group having 8 to 20 carbon atoms. A and B are each preferably independently an alkyl group or hydrogen. The ratio of m to the sum of n1 and n2 is preferably 1.0 to 5.0. This makes it possible to further lower the charge transfer resistance of the positive electrode active material layer 42. 【0046】 Block copolymers represented by the general formula (1) above can be synthesized, for example, by the esterification reaction of polyoxyalkylene glycol with monohydroxy fatty acids. 【0047】 The triblock copolymer represented by the above general formula (1) is preferably the triblock copolymer represented by the following general formula (2). In general formula (2), the ratios of A and B, and the ratio of m to the sum of n1 and n2 are as described above. [ka] 【0048】 The additive preferably contains a nonionic copolymer having the first structural unit and the second structural unit in its molecule. For example, in the above general formula (1) or general formula (2), if A and B are each independently an alkyl group or hydrogen, the copolymer represented by the above general formula (1) or general formula (2) is nonionic. The copolymers contained in the additives are nonionic, which makes them easily soluble in organic solvents. Here, the positive electrode active material layer 42 may be a coated positive electrode mixture paste containing the positive electrode active material, the additives, optional components, and a dispersion solvent, which has been dried. The organic solvent can be incorporated into the positive electrode mixture paste used to produce the positive electrode active material layer 42. Since nonionic copolymers dissolve easily in positive electrode mixture paste containing organic solvents, the non-uniform distribution of the copolymers is further suppressed in a positive electrode active material layer 42 produced from such a positive electrode mixture paste. The solid electrolyte, which will be described in detail later, may be dispersed in an organic solvent because it can degrade with water. Therefore, when producing a positive electrode active material layer 42 containing a solid electrolyte, incorporating nonionic copolymers into a positive electrode mixture paste containing organic solvents makes it possible to produce a positive electrode active material layer 42 in which the distribution of nonionic copolymers is nearly uniform. 【0049】 The number-average molecular weight (Mn) of the above copolymer (including the above block copolymer) is preferably 2,000 or more and 20,000 or less, more preferably 3,000 or more. It is even more preferably 10,000 or less, and even more preferably 7,000 or less. By having a number-average molecular weight of 2,000 or more and 20,000 or less of the above copolymer, the charge transfer resistance of the positive electrode active material layer 42 can be further reduced. 【0050】 The number-average molecular weight (Mn) mentioned above is measured by gel permeation chromatography (GPC) under the following measurement conditions. Detector: Differential refractive index (RI) Column temperature: 40℃ Flow rate: 0.8mL / min. Column: 30 x 300 mm PLgel 100A, 1000A, and 10,000A columns connected in series. Calibration curve: Standard polystyrene (150-450,000 Da) Eluent: Tetrahydrofuran (THF) (containing 1% by mass of triethylamine (TEA)) 【0051】 The positive electrode active material layer 42 preferably contains 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more, of the additive (including the block copolymer) per 100 parts by mass of the positive electrode active material. By having the above amount of the additive, the charge transfer resistance of the positive electrode active material layer 42 can be further reduced. The positive electrode active material layer 42 preferably contains 10 parts by mass or less, and more preferably 5 parts by mass or less, of the additive (including the block copolymer mentioned above) per 100 parts by mass of the positive electrode active material. By having the above amount of the additive, the charge transfer resistance of the positive electrode active material layer 42 can be further reduced. 【0052】 Examples of binders included in the positive electrode active material layer 42 of this embodiment include thermoplastic resins such as fluororesins (polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), etc.), polyethylene, polypropylene, polyacrylic, and polyimide; elastomers (rubber-based binders) such as ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), and fluororubber; and polysaccharide polymers. In the positive electrode active material layer 42, at least the particles (clumps) of the positive electrode active material and the solid electrolyte are bound to each other via the binder. 【0053】 The binder content in the positive electrode active material layer 42 is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.1% by mass or more and 7.0% by mass or less. Having the binder content within this range allows for stable retention of the positive electrode active material and the solid electrolyte. 【0054】 The positive electrode active material layer 42 preferably contains the above-mentioned additives and a binder. This allows for stable retention of the positive electrode active material and solid electrolyte in the positive electrode active material layer 42 while lowering the charge transfer resistance of the positive electrode active material layer 42. Furthermore, the positive electrode active material layer 42 containing the above-mentioned additives exhibits a more reliable effect in reducing charge transfer resistance due to the inclusion of the additives than in the case where the binder is not included. 【0055】 The conductive agent that may be included in the positive electrode active material layer 42 of this embodiment is not particularly limited as long as it is a conductive material. Examples of such conductive agents include carbonaceous materials, metals, conductive ceramics, etc. Examples of carbonaceous materials include graphite, non-graphitic carbon, graphene-based carbon, etc. Examples of non-graphitic carbon include carbon fiber, pitch-based carbon fiber, carbon black, etc. Examples of carbon black include furnace black, acetylene black, Ketjen black, etc. Examples of graphene-based carbon include graphene, carbon nanotubes (CNTs), fullerenes, etc. The conductive agent may be in the form of granules or fibers, etc. One of the conductive agents may be used alone, or two or more may be used in mixture form. Furthermore, the above materials may be used in composite form. For example, a material composite of carbon black and CNTs may be used. 【0056】 When the positive electrode active material layer 42 contains a conductive agent, the content of the conductive agent in the positive electrode active material layer 42 is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 9% by mass or less. By having the conductive agent content within the above range, the energy density of the secondary battery can be increased. 【0057】 If the positive electrode active material layer 42 contains a thickening agent, examples of the thickening agent include polysaccharide polymers such as carboxymethylcellulose (CMC) and methylcellulose. If the thickening agent has a functional group that reacts with lithium, etc., this functional group may be deactivated beforehand by methylation or the like. 【0058】 (Negative electrode) The negative electrode 50 comprises a negative electrode substrate 51 and a negative electrode active material layer 52 that overlaps the negative electrode substrate 51 either directly or via a predetermined layer. In this embodiment, the negative electrode substrate 51 and the negative electrode active material layer 52 directly overlap in the negative electrode 50. In this embodiment, the negative electrode active material layer 52 is superimposed on one side (one surface) of the negative electrode substrate 51. 【0059】 The negative electrode substrate 51 is electrically conductive. The material used for the negative electrode substrate 51 may be a metal such as copper, nickel, stainless steel, nickel-plated steel, or aluminum, or an alloy thereof. Among these, stainless steel, nickel or nickel alloy, or copper or copper alloy are preferred. Examples of the negative electrode substrate 51 include metal foil and vapor-deposited films, with metal foil being preferred from a cost perspective. Examples of the negative electrode substrate 51 include stainless steel foil, nickel foil or nickel alloy foil, or copper foil or copper alloy foil. Examples of copper foil include rolled copper foil and electrolytic copper foil. 【0060】 The average thickness of the negative electrode substrate 51 is preferably 1 μm or more and 50 μm or less, more preferably 30 μm or less, and even more preferably 15 μm or less. By setting the average thickness of the negative electrode substrate 51 within the above range, it is possible to increase the strength of the negative electrode substrate 51 while increasing the energy density per unit volume of the secondary battery. 【0061】 The negative electrode active material layer 52 comprises a negative electrode active material and a solid electrolyte (described in detail later). In this embodiment, the negative electrode active material layer 52 further comprises the above-mentioned additives. Preferably, the negative electrode active material layer 52 further comprises a binder. The negative electrode active material layer 52 optionally comprises optional components such as a conductive agent and a thickener. The binder and additives can each be selected from the materials exemplified in the positive electrode 40. Optional components such as a conductive agent and a thickener can be selected from the materials exemplified in the positive electrode 40. In the negative electrode active material layer 52 containing a binder, at least particles (clumps) of the negative electrode active material and the solid electrolyte are bound to each other via the binder. 【0062】 The negative electrode active material layer 52 may contain typical nonmetallic elements such as B, N, P, F, Cl, Br, and I, typical metallic elements such as Li, Na, Mg, Al, K, Ca, Zn, Ga, Ge, Sn, Sr, and Ba, and transition metal elements such as Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Zr, Ta, Hf, Nb, and W as components other than the negative electrode active material, solid electrolyte, additives, conductive agents, binders, and thickeners. 【0063】 The negative electrode active material can be appropriately selected from known negative electrode active materials. For lithium-ion secondary batteries, materials capable of intercalating and releasing lithium ions are typically used as negative electrode active materials. Examples of negative electrode active materials include: metallic Li; metals or metalloids such as Si and Sn; metal oxides or metalloid oxides such as Si oxide, Ti oxide, and Sn oxide; and Li4Ti5O 12 LiTiO 2、 Examples of materials include titanium-containing oxides such as TiNb2O7; polyphosphate compounds; silicon carbide; and carbon materials such as graphite and non-graphitizable carbon (easily graphitizable carbon or poorly graphitizable carbon). Among these materials, graphite and non-graphitizable carbon are preferred. In the negative electrode active material layer, one of these materials may be used alone, or two or more may be used in mixture form. 【0064】 "Graphite" refers to the average lattice plane spacing (d) of the (002) plane, determined by X-ray diffraction before charging or discharging, or during the discharge state. 002 ) refers to carbon materials with a n-scale between 0.33 nm and less than 0.34 nm. Examples of graphite include natural graphite and artificial graphite. Artificial graphite is preferred from the standpoint of obtaining materials with stable physical properties. 【0065】 "Non-graphite carbon" refers to the average lattice plane spacing (d) of the (002) plane, which is determined by X-ray diffraction before charging or during the discharge state. 002 This refers to carbon materials with a nautical radius of 0.34 nm or more and 0.42 nm or less. Non-graphitized carbons include poorly graphitizable carbons and easily graphitizable carbons. Examples of non-graphitized carbons include resin-derived materials, petroleum pitch or materials derived from petroleum pitch, petroleum coke or materials derived from petroleum coke, plant-derived materials, and alcohol-derived materials. 【0066】 Here, "discharge state" refers to a state in which sufficient lithium ions capable of being absorbed and released during charging and discharging are released from the carbon material, which is the negative electrode active material. For example, in a monoelectrode battery using a negative electrode containing a carbon material as the negative electrode active material as the working electrode and metallic Li as the counter electrode, this is the state in which the open-circuit voltage is 0.7V or higher. 【0067】 "Non-graphitizable carbon" refers to the above d 002 This refers to carbon materials with a wavelength between 0.36 nm and 0.42 nm. 【0068】 "Easily graphitizable carbon" refers to the above d002 This refers to carbon materials with a wavelength of 0.34 nm or more and less than 0.36 nm. 【0069】 The negative electrode active material is usually in the form of particles (powder). The average particle size of the negative electrode active material can be, for example, 1 nm to 100 μm. If the negative electrode active material is a carbon material, titanium-containing oxide, or polyphosphate compound, its average particle size may be 1 μm to 100 μm. If the negative electrode active material is Si, Sn, Si oxide, or Sn oxide, its average particle size may be 1 nm to 1 μm. Setting the average particle size of the negative electrode active material above the lower limit makes it easier to manufacture or handle. Setting the average particle size of the negative electrode active material below the upper limit improves the electronic conductivity of the active material layer. To obtain powder with a predetermined particle size, a pulverizer or classifier is used. The pulverizing method and powder grading method can be selected from, for example, the methods exemplified above for the positive electrode. If the negative electrode active material is a metal such as metallic Li, the negative electrode active material may be in foil form. In this case, the negative electrode active material layer 52 may consist only of the negative electrode active material. 【0070】 The content of the negative electrode active material in the negative electrode active material layer 52 is preferably 10% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 90% by mass or less, and even more preferably 30% by mass or more and 80% by mass or less. By having the negative electrode active material content within the above range, it is possible to achieve both a high energy density in the negative electrode active material layer 52 and relatively simple manufacturing of the negative electrode active material layer 52. Note that if the negative electrode active material is a metal such as metallic Li, the content of the negative electrode active material in the negative electrode active material layer 52 may be 100% by mass. 【0071】 The solid electrolyte contained in the negative electrode active material layer 52 can be appropriately selected from the solid electrolytes exemplified in the description of the solid electrolyte layer 60, which will be described in detail later. The solid electrolyte may be, for example, in the form of amorphous lumps or in the form of parts of a specific shape. The solid electrolyte contained in the negative electrode active material layer 52 may be the same type as the solid electrolyte contained in the solid electrolyte layer 60, or it may be a different type. The solid electrolyte content in the negative electrode active material layer 52 is preferably 5% by mass or more and 90% by mass or less, more preferably 10% by mass or more and 80% by mass or less, and even more preferably 15% by mass or more and 70% by mass or less. By having the solid electrolyte content in the negative electrode active material layer 52 within the above range, the energy storage element can have a relatively large electrical capacity. The negative electrode active material layer 52 may contain multiple different types of solid electrolytes. 【0072】 The negative electrode active material layer 52 preferably contains 0.01 parts by mass or more, and more preferably 0.05 parts by mass or more, of the additive (including the block copolymer) per 100 parts by mass of the negative electrode active material. By having the above amount of the additive, the charge transfer resistance of the negative electrode active material layer 52 can be further reduced. The negative electrode active material layer 52 preferably contains 10 parts by mass or less, and more preferably 5 parts by mass or less, of the additive (including the block copolymer mentioned above) per 100 parts by mass of the negative electrode active material. By using the above amounts of the polymer, the charge transfer resistance of the negative electrode active material layer 52 can be further reduced. 【0073】 Similar to the positive electrode active material layer 42 described above, the negative electrode active material layer 52 may be a coated negative electrode mixture paste containing the negative electrode active material, the above-mentioned additives, optional components, and an organic solvent, which has been dried. 【0074】 In the electrode body 2 of this embodiment, the positive electrode active material layer 42 and the negative electrode active material layer 52 face each other via the solid electrolyte layer 60. When the electrode body 2 is viewed from one direction in the stacking direction (thickness direction), the area of ​​the negative electrode active material layer 52 may be larger than the area of ​​the positive electrode active material layer 42. In other words, at least a portion of the peripheral edge of the negative electrode active material layer 52 does not have to face the positive electrode active material layer 42 in the thickness direction. It is sufficient that at least one of the active material layers of the positive electrode 40 and the negative electrode 50 in the electrode body 2 contains the above-mentioned additive. 【0075】 (Solid electrolyte layer) In the electrode body 2 of this embodiment, a solid electrolyte layer 60 containing a solid electrolyte but not an active material is disposed between the positive electrode 40 and the negative electrode 50. The thickness of the solid electrolyte layer 60 may be 5 μm or more and 200 μm or less, or 10 μm or more and 100 μm or less. 【0076】 The solid electrolyte layer 60 contains a solid electrolyte in the form of specific parts or irregularly shaped lumps, and may further contain the binder exemplified in the positive electrode 40. 【0077】 The above-mentioned solid electrolyte is an ion-conducting material that conducts ions such as lithium, sodium, potassium, magnesium, and calcium, and is a compound that remains solid even in a nitrogen atmosphere at 1 atmosphere and 25°C. Examples of the above-mentioned solid electrolyte include sulfide solid electrolytes and other solid electrolytes other than sulfide solid electrolytes. 【0078】 A sulfide solid electrolyte is preferred as the solid electrolyte contained in the solid electrolyte layer 60. Furthermore, the solid electrolyte contained in the solid electrolyte layer 60 and the solid electrolytes contained in the positive electrode active material layer 42 and the negative electrode active material layer 52 may be the same or different, but preferably, both are sulfide solid electrolytes. Using a sulfide solid electrolyte has the advantage of increasing the conductivity of ions such as lithium in the solid electrolyte layer. Additionally, because the particles of the sulfide solid electrolyte are more easily deformed, the contact area between the solid electrolyte particles and between the solid electrolyte and the active material can be increased. Therefore, there is the advantage of lowering the interfacial resistance between the solid electrolyte and the active material. 【0079】 Sulfide solid electrolytes are compounds that contain sulfur as an essential component and remain solid even under a nitrogen atmosphere at 1 atmosphere and 25°C. Examples of sulfide solid electrolytes used in lithium-ion secondary batteries include Li2S-P2S5, Li2S-GeS2, LiI-Li2S-P2S5, and Li 10 Ge-P2S 12 Examples include Li6PS5X (X=Cl, Br, I). Here, Li 10 Ge-P2S 12 This is referred to as the LGPS type, while Li6PS5X is referred to as the argyrodite type. 【0080】 Other solid electrolytes that may be included in the solid electrolyte layer 60, etc. include oxide solid electrolytes, , Nitrogen Examples include oxide solid electrolytes. The solid electrolyte layer 60 may contain an inorganic solid electrolyte such as the sulfide solid electrolyte or oxide solid electrolyte mentioned above, and may also contain a polymer solid electrolyte. 【0081】 Oxide solid electrolytes are compounds that contain oxygen as an essential component and remain solid even under a nitrogen atmosphere at 1 atmosphere and 25°C. Examples of oxide solid electrolytes include perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, and garnet-type oxides. Examples of perovskite-type oxides include Li x La 1-x Examples of such oxides include those represented by TiO3 (Li-La-Ti-O perovskite-type oxides). 0.29 La 0.57 TiO3, Li 0.35 La 0.55 Examples include TiO3. Examples of NASICON-type oxides include Li 1.3 Al 0.3 Ti 1.7 Examples include (PO4)3. Examples of LISICON-type oxides include Li4SiO4-Li3PO4 and Li3BO3-Li3PO4. Examples of garnet-type oxides include Li7La3Zr2O 12 Examples include Li-La-Zr-O based oxides. 【0082】 nitrogen Examples of ion solid electrolytes include Li3N. 【0083】 Examples of polymer solid electrolytes include ion-conducting polymers. Such ion-conducting polymers include chemically modified and crosslinked polymers of polyether-based, polyester-based, polyamine-based, or polysulfide-based polymers. 【0084】 In the positive electrode active material layer 42, the negative electrode active material layer 52, and the solid electrolyte layer 60 of the electrode body 2, the proportion of sulfide solid electrolyte among the solid electrolyte may be 95% by mass or more. 【0085】 The solid electrolyte layer 60 may also be a coated material (without active material) of a paste for solid electrolyte layers containing a solvent and solid electrolyte particles, which has been dried. 【0086】 <Manufacturing method for all-solid-state energy storage elements> The method for manufacturing the energy storage element of this embodiment includes, for example, the steps of manufacturing an electrode body and assembling the energy storage element by housing the electrode body in a container 3. 【0087】 The process of manufacturing an electrode body includes, for example, preparing a positive electrode mixture paste, a negative electrode mixture paste, and a paste for the solid electrolyte layer, manufacturing a positive electrode active material layer from a coating of the positive electrode mixture paste, manufacturing a negative electrode active material layer from a coating of the negative electrode mixture paste, and manufacturing a solid electrolyte layer from a coating of the paste for the solid electrolyte layer. 【0088】 (Preparation of each paste) The positive electrode mixture paste contains at least particles of positive electrode active material, particles of solid electrolyte, and a solvent; the negative electrode mixture paste contains at least particles of negative electrode active material, particles of solid electrolyte, and a solvent; and the paste for the solid electrolyte layer contains at least particles of solid electrolyte and a solvent. At least one of the positive electrode mixture paste and the negative electrode mixture paste further contains the above-mentioned additives. Furthermore, at least one of the positive electrode mixture paste and the negative electrode mixture paste preferably contains a binder. 【0089】 The solvent mentioned above is not particularly limited and may be, for example, an organic solvent or water. As the solvent, for example, any solvent that does not degrade the solid electrolyte used can be appropriately selected. Since solid electrolytes can degrade with water, the solvent may be an organic solvent. 【0090】 (Fabrication of positive electrode active material layer, solid electrolyte layer, and negative electrode active material layer) In the process of producing the positive electrode active material layer, a drying treatment is performed on the coated material of the positive electrode mixture paste to volatilize the solvent, and then a pressing treatment is performed. The process of producing the negative electrode active material layer and the process of producing the solid electrolyte layer can be carried out in the same manner. 【0091】 • Fabrication of the positive electrode active material layer As the positive electrode substrate 41, for example, a metal foil or alloy foil as described above is prepared. As shown in Figure 4, the positive electrode active material layer 42 can be fabricated by performing the following operation. (I) The positive electrode mixture paste (indicated as PT) is applied to the metal foil or alloy foil of the positive electrode substrate 41. This creates a layer of the coating on the positive electrode substrate 41. Conventional general methods can be used as the coating method. (II) The coated material is subjected to a drying treatment to volatilize the solvent contained in the coated positive electrode mixture paste. For example, the solvent is volatilized and removed from the coated material by heat treatment. The set temperature during the heat treatment may be, for example, 40°C to 150°C. The heat treatment may be carried out under reduced pressure. (III) After the solvent has evaporated, the coated material (positive electrode active material layer 42) is subjected to a pressing process (indicated by a dashed arrow). If necessary, the pressing process is carried out while heating. (IV) A press-treated positive electrode active material layer 42 is formed. 【0092】 • Preparation of the solid electrolyte layer As shown in Figure 5, the solid electrolyte layer 60 can be fabricated by performing the following operations. (i) A paste for the solid electrolyte layer (indicated as PT') is applied to the positive electrode active material layer 42. This creates a layer of the applied material on the positive electrode active material layer 42. Conventional general methods can be used as the application method (coating method). (ii) The coated material is subjected to a drying treatment to volatilize the solvent contained in the paste for the solid electrolyte layer. For example, the solvent is volatilized and removed from the coated material by heat treatment. The temperature set during the heat treatment may be, for example, within the temperature range used when manufacturing the positive electrode active material layer 42. (iii) After the solvent has evaporated, the coated material (solid electrolyte layer 60) is subjected to a pressing process (indicated by a dashed arrow). If necessary, the pressing process is carried out while heating. (iv) A pressed solid electrolyte layer 60 is formed. 【0093】 • Fabrication of the negative electrode active material layer Although not shown in the diagram, the negative electrode active material layer 52 can be fabricated by the same method as described above for fabricating the positive electrode active material layer or the solid electrolyte layer. 【0094】 In the process of manufacturing the electrode body, after creating a laminate of the positive electrode active material layer 42, the solid electrolyte layer 60, and the negative electrode active material layer 52 as described above, the negative electrode substrate 51 is further stacked on top, and the electrode body 2 can be manufactured by applying a press treatment from both sides in the thickness direction. In addition, in the process of manufacturing the electrode body, a positive electrode 40 may be manufactured by stacking a positive electrode active material layer 42 on a positive electrode substrate 41, and a laminate of a negative electrode 50 and a solid electrolyte layer 60 may be manufactured by stacking a negative electrode active material layer 52 on a negative electrode substrate 51. Then, the electrode body 2 may be manufactured by stacking this laminate with the positive electrode 40 and further applying a press treatment from both sides in the thickness direction. 【0095】 (Process of assembling energy storage elements) In this process, the fabricated electrode body 2 is placed in a container 3, and the energy storage element 1 is assembled so that the positive electrode 40 and negative electrode 50 of the electrode body 2 are electrically connected to the external terminals of the energy storage element 1. A general method can be used to assemble the energy storage element. 【0096】 As described above, the energy storage element 1 of this embodiment can be manufactured. 【0097】 <Configuration of the energy storage device> The energy storage element 1 of this embodiment can be mounted as an energy storage device 100 (battery module) formed by assembling multiple energy storage elements 1 in power supplies for vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), power supplies for electronic devices such as personal computers and communication terminals, or power storage devices. In this case, it is sufficient that the technology of the present invention is applied to at least one of the energy storage elements 1 included in the energy storage device 100. Figure 6 shows an example of a power storage device 100, which is formed by further assembling power storage units 10, each consisting of two or more electrically connected power storage elements 1. The power storage device 100 may include busbars (not shown) that electrically connect two or more power storage elements 1, busbars (not shown) that electrically connect two or more power storage units 10, etc. The power storage unit 10 or the power storage device 100 may include a condition monitoring device (not shown) that monitors the state of one or more power storage elements. 【0098】 <Other Embodiments> Furthermore, the energy storage element of the present invention is not limited to the embodiments described above, and various modifications may be made without departing from the spirit of the present invention. For example, the configuration of one embodiment may be added to the configuration of another embodiment, and a part of the configuration of one embodiment may be replaced with the configuration of another embodiment or with well-known technology. In addition, a part of the configuration of one embodiment may be deleted. Also, well-known technology may be added to the configuration of one embodiment. 【0099】 In the above embodiment, the case in which the energy storage element 1 is used as a fully solid-state secondary battery (for example, a fully solid-state lithium-ion secondary battery) that can be charged and discharged has been described, but the type, shape, dimensions, capacity, etc. of the energy storage element are arbitrary. 【0100】 In the above embodiment, a positive electrode 40 in which a positive electrode active material layer 42 is superimposed on one side of a positive electrode substrate 41, and a negative electrode 50 in which a negative electrode active material layer 52 is superimposed on one side of a negative electrode substrate 51 have been described. However, in the positive electrode, positive electrode active material layers may be superimposed on both sides of the positive electrode substrate 41, and in the negative electrode, negative electrode active material layers may be superimposed on both sides of the negative electrode substrate. 【0101】 In the energy storage element 1 of the above embodiment, the additive contained in the positive electrode active material layer 42 or the negative electrode active material layer 52 of the electrode body 2 contains a first structural unit in which hydrocarbon groups and ether bonds are alternately repeated, and a second structural unit in which hydrocarbon groups and ester bonds are alternately repeated, as described above. The ether bonds in the first structural unit have polar lone pairs of electrons on the oxygen atom, and therefore tend to be adsorbed onto active materials or solid electrolytes which are polar materials. In particular, the hydrocarbon groups in the second structural unit have hydrophobic hydrocarbon chains with a relatively large number of carbon atoms, and therefore tend to be adsorbed onto binders which are hydrophobic materials. Copolymers having the above-described first and second structural units in their molecules are thought to adsorb to the active material or solid electrolyte at the ether bond portion of the first structural unit. The copolymer adsorbed to the active material or solid electrolyte is thought to prevent the binder from adsorbing to the active material or solid electrolyte due to steric hindrance. This suppresses excessive coating of the surface of the particles of the active material or solid electrolyte with binder. Therefore, it is thought that the number of interfaces in which the active material and solid electrolyte come into contact without the binder increases. This phenomenon is thought to reduce the charge transfer resistance of the active material layer. Furthermore, the copolymer having the above-described first and second structural units in its molecule is preferably a block copolymer. Random copolymers tend to form random coil structures, but block copolymers have a certain degree of control over their conformation. Therefore, in the above block copolymer, the first structural unit in which the ether structure is repeated and the second structural unit containing hydrocarbon groups with more carbon atoms than the hydrocarbon groups of the first structural unit can each have a sufficient number of repetitions. Consequently, the first structural unit and the second structural unit can be arranged so as to be sufficiently far apart from each other. This makes it easier for the effects of the first structural unit and the second structural unit to be exerted independently of each other, and for one effect to interfere with the other. Specifically, the effect of the ether bond portion of the first structural unit adsorbing onto the active material or solid electrolyte and the effect of the hydrocarbon group portion of the second structural unit preventing the adsorption of the binder onto the active material or solid electrolyte can each be effectively exerted. Because the above-mentioned block copolymer can more reliably achieve these effects, the charge transfer resistance of the active material layer can be further reduced as described above. 【0102】 The energy storage element 1 in the above embodiment is preferably an all-solid-state energy storage element. That is, the energy storage element 1 in the above embodiment preferably does not contain an electrolyte in the positive electrode active material layer 42, the negative electrode active material layer 52, and the solid electrolyte layer 60. 【0103】 In the above embodiment, an all-solid-state energy storage element was described in detail, but the energy storage element of the present invention is not limited to an all-solid-state energy storage element. The positive electrode active material layer, negative electrode active material layer, and solid electrolyte layer constituting the energy storage element of the present invention preferably contain substantially no electrolyte, but may contain an electrolyte. The electrolyte can be appropriately selected from known electrolytes. When the energy storage element of the present invention is a lithium-ion secondary battery, for example, a solution of LiPF6 dissolved as an electrolyte salt in a solvent mixed with cyclic carbonate and chain carbonate can be used as the electrolyte. [Examples] 【0104】 The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples. 【0105】 First, each block copolymer for additives was synthesized as follows. All of these block copolymers have the molecular structure of general formula (2) above. 【0106】 (Synthesis Example 1: Synthesis of Block Copolymer 1 for Additives) A flask equipped with a distillation apparatus and a mixing stirrer was filled with 73 g of polyethylene glycol 600 (PEG600). It was heated to 85-90°C under a nitrogen atmosphere with stirring. 450 g of 12-hydroxystearic acid was added to the flask, and then 1.4 g of tetrabutyl orthotitanate (TBT) was added as a catalyst. The flask was heated to 222°C while monitoring the acid value. Heating was stopped when the acid value fell below 10 mgOH / g, and block copolymer 1 was synthesized. The number-average molecular weight of the obtained block copolymer 1 was measured by gel permeation chromatography (GPC). The number-average molecular weight was 3,400. The GPC measurement conditions were as described above (and the same applies hereafter). 【0107】 (Synthesis Example 2: Synthesis of Block Copolymer 2 for Additives) Block copolymer 2 was synthesized in the same manner as in Example 1, except that 219 g of polyethylene glycol 1500 (PEG1500) was used instead of polyethylene glycol 600. The number-average molecular weight of the obtained block copolymer 2 was 4,900. 【0108】 (Synthesis Example 3: Synthesis of Block Copolymer 3 for Additives) Block copolymer 3 was synthesized in the same manner as in Example 1, except that 91 g of polyethylene glycol 1500 (PEG1500) and 202 g of polyethylene glycol 4000 (PEG4000) were used instead of polyethylene glycol 600. The number-average molecular weight of the obtained block copolymer 3 was 6,400. 【0109】 In addition, we purchased commercially available reference compounds 1-3, each possessing the following molecular structures, as reference compounds. • Reference compound 1: Tween20 (polyoxyethylene (20) sorbitan monolaurate) • Reference compound 2: Span20 (sorbitan monolaurate) • Reference compound 3: Polyethylene glycol monostearate (9 to 13 moles of oxiylene added) 【0110】 Next, each of the block copolymers synthesized as described above, or each of the reference compounds described above, was used as an additive to manufacture an energy storage element (half-cell of an all-solid-state lithium-ion secondary battery). The manufactured energy storage element is also referred to as an all-solid-state secondary battery. 【0111】 (Example 1) <Preparation of positive electrode mixture paste> Particulate positive electrode active material (having an α-NaFeO2 type crystal structure, LiNi 0.5 Co 0.2 Mn 0.3 A positive electrode mixture paste was prepared by mixing a lithium transition metal composite oxide (represented by O2), a particulate sulfide solid electrolyte (having an argyrodite-type structure and containing the elements lithium, phosphorus, sulfur, and chlorine), a conductive agent (carbon fiber), a rubber-based binder, a cellulose-based thickener, an organic solvent (a mixed solvent of tetralin and anisole), and an additive (block copolymer 1 from Synthesis Example 1). The additive (block copolymer 1 from Synthesis Example 1) was mixed in an amount of 0.5 parts by mass per 100 parts by mass of positive electrode active material. 【0112】 <Fabrication of the positive electrode> The positive electrode mixture paste was applied to the carbon-coated side of a positive electrode substrate (a 20 μm thick aluminum foil with a pre-applied carbon coating layer on one side), and then dried to remove the organic solvent from the positive electrode mixture paste. In this way, a positive electrode was fabricated in which a 60 μm thick positive electrode active material layer was formed on the positive electrode substrate. 【0113】 <Fabrication of all-solid-state secondary batteries> A positive electrode comprising a positive electrode active material layer with a thickness of 60 μm and an aluminum positive electrode substrate with a thickness of 20 μm was punched out in the thickness direction to a predetermined size. A solid electrolyte was introduced into the Macol tube from one side, and a solid electrolyte layer with a thickness of 800 μm was formed by pressing it at 100 MPa using a stainless steel jig. Then, the positive electrode was inserted into the Macol tube and pressed at 580 MPa. This bonded the positive electrode active material layer and the solid electrolyte layer inside the Macol tube. Next, the lithium-indium counter electrode was inserted from the other side of the Macol tube. This brought the inserted lithium-indium counter electrode and the positive electrode inside the Macol tube facing each other via the solid electrolyte layer. Then, inside the Macol tube, the positive electrode, the solid electrolyte layer, and the counter electrode were sandwiched together by a stainless steel jig. After that, the stainless steel jigs on both sides were fastened together with bolts, and leads were connected to the stainless steel jigs on both sides as external terminals, thereby manufacturing the energy storage element (all-solid-state secondary battery) of Example 1. 【0114】 (Examples 2 and 3) The energy storage elements (all-solid-state secondary batteries) of Examples 2 and 3 were manufactured in the same manner as in Example 1, except that block copolymer 2 or 3 from Synthesis Example 2 or Synthesis Example 3, respectively, were mixed as additives into the cathode mixture paste, instead of block copolymer 1 from Synthesis Example 1. 【0115】 (Comparative Example 1) A storage element (all-solid-state secondary battery) of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the additive was not mixed into the positive electrode mixture paste. 【0116】 (Comparative Example 2) A comparative example (all-solid-state secondary battery) was manufactured in the same manner as in Example 1, except that the above-mentioned reference compound 1 was mixed into the cathode mixture paste as an additive instead of the block copolymer 1 in Synthesis Example 1. 【0117】 (Comparative Example 3) A comparative example (all-solid-state secondary battery) was manufactured in the same manner as in Example 1, except that the above-mentioned reference compound 2 was mixed into the cathode mixture paste as an additive instead of block copolymer 1 in Synthesis Example 1. 【0118】 (Comparative Example 4) A power storage element (all-solid-state secondary battery) of Comparative Example 4 was manufactured in the same manner as in Example 1, except that the above-mentioned Reference Compound 3 was mixed into the cathode mixture paste as an additive instead of the block copolymer of Synthesis Example 1. 【0119】 <Performance Evaluation> (Charge transfer resistance of the positive electrode active material layer) Each of the above energy storage elements underwent three charge-discharge cycles. Charging was performed using a constant current of 0.1C and a termination voltage of 3.63V, while discharging was performed using a constant current of 0.1C and a termination voltage of 2.38V. A 10-minute pause was provided between each charge-discharge and discharge cycle. Next, constant current charging was performed under the same conditions as above to achieve a State of Charge (SOC) of 100%. From the Cole-Cole plot obtained by AC impedance measurement at 25°C (current amplitude 10mV, frequency range 1MHz-0.1mHz), the value of the real axis resistance Re(Z') of the arc corresponding to the charge transfer reaction was read and recorded as the charge transfer resistance (Ω) of the positive electrode active material layer. Then, the relative values ​​of the charge transfer resistance of the positive electrode active material layer in each example and comparative example were determined, with the charge transfer resistance of the positive electrode active material layer in Comparative Example 1 set to 100. The results are shown in Table 1. 【0120】 [Table 1] 【0121】 As can be seen from Table 1, the charge transfer resistance of the positive electrode active material layer was low in the energy storage elements of Examples 1 to 3. On the other hand, the charge transfer resistance of the positive electrode active material layer was not necessarily low in the energy storage elements of Comparative Examples 1 to 4. 【0122】 (Example 4) <Preparation of negative electrode mixture paste> A negative electrode mixture paste was prepared by mixing particulate negative electrode active material (graphite), particulate sulfide solid electrolyte (having an argyrodite-type structure and containing the elements lithium, phosphorus, sulfur, and chlorine), conductive agent (carbon fiber), rubber-based binder, cellulose-based thickener, organic solvent (a mixed solvent of tetralin and anisole), and additive (block copolymer 1 from Synthesis Example 1). The additive (block copolymer 1 from Synthesis Example 1) was mixed in an amount of 0.5 parts by mass per 100 parts by mass of negative electrode active material. 【0123】 <Fabrication of the negative electrode> The negative electrode mixture paste was applied to the carbon-coated side of a negative electrode substrate (a 20 μm thick stainless steel foil with a pre-applied carbon coating layer on one side), and then dried to remove the organic solvent from the negative electrode mixture paste. In this way, a negative electrode was fabricated in which a 60 μm thick negative electrode active material layer was formed on the negative electrode substrate. 【0124】 <Fabrication of all-solid-state secondary batteries> The above negative electrode was punched out to a predetermined size. A solid electrolyte was introduced into the Macol tube from one side and pressed at 100 MPa using a stainless steel jig to form a solid electrolyte layer with a thickness of 800 μm. Subsequently, the negative electrode was inserted into the Macol tube and pressed at 580 MPa. This bonded the negative electrode active material layer and the solid electrolyte layer inside the Macol tube. Next, the lithium-indium counter electrode was inserted from the other side of the Macol tube. This brought the inserted lithium-indium counter electrode and the negative electrode inside the Macol tube facing each other via the solid electrolyte layer. Then, inside the Macol tube, the negative electrode, the solid electrolyte layer, and the counter electrode were sandwiched together by a stainless steel jig. After that, the stainless steel jigs on both sides were fastened together with bolts, and leads were connected to the stainless steel jigs on both sides as external terminals, thereby manufacturing the energy storage element (all-solid-state secondary battery) of Example 4. 【0125】 (Examples 5 and 6) The energy storage elements (all-solid-state secondary batteries) of Examples 5 and 6 were manufactured in the same manner as in Example 4, except that block copolymer 2 or 3 from Synthesis Example 2 or Synthesis Example 3, respectively, were mixed as additives into the negative electrode mixture paste, instead of block copolymer 1 from Synthesis Example 1. 【0126】 (Comparative Example 5) A power storage element (all-solid-state secondary battery) for Comparative Example 5 was manufactured in the same manner as in Example 4, except that the additive was not mixed into the negative electrode mixture paste. 【0127】 (Comparative Examples 6 to 8) The energy storage elements (all-solid-state secondary batteries) of Comparative Examples 6 to 8 were manufactured in the same manner as in Example 4, except that the above-mentioned Reference Compounds 1 to 3 were mixed as additives into the negative electrode mixture paste, respectively, instead of block copolymer 1 in Synthesis Example 1. 【0128】 <Performance Evaluation> (Charge transfer resistance of the negative electrode active material layer) Each of the above energy storage elements underwent three charge-discharge cycles. Here, "discharge" refers to current flowing in the direction of electrochemical oxidation of the negative electrode, and "charge" refers to current flowing in the direction of electrochemical reduction of the negative electrode. Here, charging was performed as constant current charging with a charging current of 0.1C and a charging termination voltage of -0.57V, and discharging was performed as constant current discharge with a discharge current of 0.1C and a discharge termination voltage of 0.88V. A 10-minute pause was provided between charging and discharging, and between discharging and charging. Next, an amount of electricity equivalent to 50% of the discharge capacity of the third cycle was charged with a charging current of 0.1C to a state of charge (SOC) of 50%. From the Cole-Cole plot obtained by AC impedance measurement at 25°C (current amplitude 10mV, frequency range 1MHz-0.1mHz), the value of the real axis resistance Re(Z') of the arc corresponding to the charge transfer reaction was read and recorded as the charge transfer resistance (Ω) of the negative electrode active material layer. Then, setting the charge transfer resistance of the negative electrode active material layer in Comparative Example 5 to 100, the relative values ​​of the charge transfer resistances of the negative electrode active material layers in each example and each comparative example were determined. The results are shown in Table 2. 【0129】 [Table 2] 【0130】 As can be seen from Table 2, the charge transfer resistance of the negative electrode active material layer was low in the energy storage elements of Examples 4 to 6. On the other hand, the charge transfer resistance of the negative electrode active material layer was not necessarily low in the energy storage elements of Comparative Examples 5 to 8. [Explanation of symbols] 【0131】 1: Energy storage element (all-solid-state lithium-ion secondary battery), 2: Electrode body, 3: Container, 4: Positive terminal, 5: Negative terminal, 40: Positive electrode, 41: positive electrode base material, 42: positive electrode active material layer, 50: negative electrode, 51: negative electrode base material, 52: negative electrode active material layer, 60: solid electrolyte layer, 10: Energy storage unit, 100: Energy storage device.

Claims

[Claim 1] It comprises an active material layer containing an active material and an inorganic solid electrolyte, The active material layer further contains additives, The additive comprises a copolymer containing in its molecule a first structural unit in which hydrocarbon groups and ether bonds are alternately repeated, and a second structural unit in which hydrocarbon groups and ester bonds are alternately repeated. The copolymer is a block copolymer in which the first structural unit and the second structural unit are arranged along the main chain. The aforementioned block copolymer is represented by the following general formula (1), and is an electrode body. 【Chemistry 1】 (However, in general formula (1), R1 is a saturated hydrocarbon group having 1 to 4 carbon atoms, R2' and R2'' are each independently saturated hydrocarbon groups having 4 to 20 carbon atoms, A and B are hydrogen, and m, n1 and n2 are each independently positive integers.) [Claim 2] The electrode body according to claim 1, wherein the number-average molecular weight of the copolymer is 2,000 or more and 20,000 or less. [Claim 3] The electrode body according to claim 1, wherein in the general formula (1), the ratio of m to the sum of n1 and n2 is 0.8 or more and 8.0 or less. [Claim 4] The electrode body according to claim 1, wherein R1 in the general formula (1) is a saturated hydrocarbon group having 2 or 3 carbon atoms. [Claim 5] A storage element comprising the electrode body described in claim 1.

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