Electrode composition, electrode for secondary battery, secondary battery, electrolyte permeation method, and method for manufacturing secondary battery

Abstract

An electrode composition for a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following (1) to (4): (1) contains an active material and an additive, and does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 or less; (3) the HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 or less; and (4) the weight average molecular weight (Mw) of the additive is 50,000 or less.

Description

Technical Field

[0001] This invention relates to electrode compositions, electrodes for secondary batteries, secondary batteries, electrolyte permeation methods, and methods for manufacturing secondary batteries. Background Technology

[0002] Lithium-ion batteries and other rechargeable batteries have been practically used in portable devices such as mobile phones and laptops, as well as as power sources in hybrid and electric vehicles. To further expand their adoption, there is a demand for higher capacity and higher output from rechargeable batteries, leading to attempts to apply various technologies.

[0003] One method to increase the capacity of secondary batteries is to increase electrode density. By densely packing the active material, greater capacity can be obtained. However, increasing electrode density makes it difficult for the electrolyte to penetrate the electrodes, resulting in the extraction of less capacity than theoretically possible and a deterioration in output characteristics.

[0004] To address this issue, Patent Document 1 discloses a technique for improving electrolyte permeability by creating grooves on the electrode surface. Patent Document 2 discloses a technique for improving electrolyte permeability by studying the particle size and shape of the active material. Furthermore, Patent Document 3 discloses a technique for improving electrolyte permeability by adjusting the electrode density.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-27633

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-151088

[0009] Patent Document 3: Japanese Patent Application Publication No. 2020-053282 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, the method in Patent Document 1 has the following problem: it has a step of pressing with a roller with concave and convex surfaces in order to set grooves on the electrode surface, which requires the introduction of new equipment.

[0012] Furthermore, although some improvement in permeability was observed in the methods of patent documents 2 and 3, the effect was not sufficient.

[0013] The present invention is an invention to solve the above-mentioned problems, and its object is to provide an electrode composition capable of manufacturing an electrode with excellent electrolyte permeability.

[0014] Methods for solving problems

[0015] The inventors conducted in-depth research, which resulted in the completion of this invention.

[0016] The present invention relates to any of the following solutions.

[0017] An electrode composition is provided for use in a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (4): (1) it contains an active substance and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0018] An electrode composition is provided for use in a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (3): (1) it contains an active material, a binder resin, and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0019] An electrode for a secondary battery is formed by compressing the above-mentioned electrode composition.

[0020] A secondary battery having the aforementioned electrodes for a secondary battery.

[0021] A secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (4): (1) the secondary battery electrode layer contains an active material, an electrolyte, and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0022] A secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (3): (1) the secondary battery electrode layer contains an active material, an electrolyte, a binder resin, and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0023] An electrolyte permeation method is a method for permeating an electrolyte into an electrode composition, wherein the electrolyte permeation method satisfies all of the following conditions (1) to (4): (1) the electrode composition contains an active substance and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0024] An electrolyte permeation method is a method for permeating an electrolyte into an electrode composition, wherein the electrolyte permeation method satisfies all of the following conditions (1) to (3): (1) the electrode composition contains an active substance, a binder resin, and an additive; (2) the HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0025] A method for manufacturing a secondary battery includes the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the following conditions (1) to (4): (1) the electrode composition layer contains an active material and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0026] A method for manufacturing a secondary battery includes the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the following conditions (1) to (3): (1) the electrode composition layer contains an active material, a binder resin, and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0027] The effects of the invention

[0028] According to the present invention, an electrode composition capable of manufacturing an electrode with excellent electrolyte permeability can be provided. Detailed Implementation

[0029] [Electrode Composition]

[0030] As electrode compositions of the present invention, there are electrode compositions of the first type and electrode compositions of the second type.

[0031] The electrode composition of the first type is an electrode composition for a secondary battery electrode layer containing an electrolyte, and is an electrode composition that satisfies all the conditions (1) to (4) below.

[0032] (1) Contains active substances and additives, but does not contain binder resin;

[0033] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0034] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following;

[0035] (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0036] The electrode composition of the second type is an electrode composition for a secondary battery electrode layer containing an electrolyte, and is an electrode composition that satisfies all the conditions (1) to (3) below.

[0037] (1) Contains active substances, binder resins and additives;

[0038] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0039] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0040] The electrode composition of the first embodiment differs from that of the electrode composition of the second embodiment in the following aspects, while all other aspects are the same.

[0041] • The electrode composition of the first embodiment does not contain a binder resin in (1). The electrode composition of the second embodiment contains a binder resin in (1).

[0042] • The electrode composition of the first type specifies that the weight average molecular weight (Mw) of the additive (4) is 50,000 or less, while the electrode composition of the second type does not have this condition.

[0043] The same aspects of the electrode compositions of both the first and second methods will be described below.

[0044] The electrode composition of the present invention is an electrode composition for a secondary battery electrode layer containing an electrolyte. The electrode composition of the present invention does not contain an electrolyte itself; by including an electrolyte in the electrode composition, a secondary battery electrode layer can be formed.

[0045] The electrode composition contains active substances and additives.

[0046] (Active substances)

[0047] The active material can be either a positive electrode active material or a negative electrode active material.

[0048] As positive electrode active materials, examples include composite oxides of lithium and transition metals {composite oxides with one transition metal (LiCoO2, LiNiO2, LiAlMnO4, LiMnO2, and LiMn2O4, etc.) and composite oxides with two transition metal elements (e.g., LiFeMnO4, LiNi... 1-x Co x O2, LiMn 1-y Co y O2, LiNi 1 / 3 Co 1 / 3 Al 1 / 3 O2 and LiNi 0.8 Co 0.15 Al 0.05 O2) and composite oxides containing three or more transition metal elements [e.g., LiM] a M' b M” c O2 (M, M', and M" are each a different transition metal element, and satisfy a + b + c = 1. For example, LiNi)0.8 Co 0.1 Mn 0.1 O2, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 The following can be used in combination: lithium-containing transition metal phosphates (e.g., LiFePO4, LiCoPO4, LiMnPO4 and LiNiPO4), transition metal oxides (e.g., MnO2 and V2O5), transition metal sulfides (e.g., MoS2 and TiS2), and conductive polymers (e.g., polyaniline, polypyrrole, polythiophene, polyacetylene, poly(p-phenylene oxide), and polyvinylcarbazole).

[0049] It should be noted that lithium-containing transition metal phosphates can also be phosphates formed by replacing some transition metal sites with other transition metals.

[0050] Examples of anode active materials include carbon-based materials [graphite (graphite, artificial graphite, natural graphite), non-graphitizable carbon (hard carbon), amorphous carbon, sintered resins (e.g., substances formed by sintering and carbonizing phenolic resins and furan resins); cokes (e.g., pitch coke, needle coke, and petroleum coke) and carbon fibers], and silicon-based materials [silicon, silicon oxide (SiO₂)]. x Silicon-carbon composites (substances formed by coating the surface of carbon particles with silicon and / or silicon carbide, substances formed by coating the surface of silicon particles or silicon oxide particles with carbon and / or silicon carbide, and silicon carbide, etc.) and silicon alloys (silicon-aluminum alloys, silicon-lithium alloys, silicon-nickel alloys, silicon-iron alloys, silicon-titanium alloys, silicon-manganese alloys, silicon-copper alloys, and silicon-tin alloys, etc.), conductive polymers (e.g., polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, and titanium, etc.), metal oxides (titanium oxides and lithium titanium oxides, etc.) and metal alloys (e.g., lithium-tin alloys, lithium-aluminum alloys, and lithium-aluminum-manganese alloys, etc.), and mixtures thereof with carbon-based materials, etc.

[0051] When the electrode active material is the negative electrode active material, artificial graphite or natural graphite is preferred. The shape of the negative electrode active material is not particularly limited; examples include spherical graphite and flake graphite.

[0052] The content of active material in the electrode composition is not particularly limited, but from the perspective of improving electrode density and battery capacity, a high content of active material is preferred, preferably 90% to 95% by weight.

[0053] (additive)

[0054] An additive is a compound that meets the following conditions.

[0055] (2) The HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 the following.

[0056] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

[0057] In the electrode composition of the first method, the following condition is further satisfied: "(4) The weight-average molecular weight (Mw) of the additive is 50,000 or less." This is described below.

[0058] The HSP distance is determined by the Hansen solubility parameters (HSP values) of the two substances used to determine the HSP distance.

[0059] The HSP value is an index obtained by decomposing the Hildebrand solubility parameter (SP value) into three components: the dispersive component δD, the polar component δP, and the hydrogen bonding component δH, taking into account the polarity of the physical properties. It possesses the characteristics of "SP". 2 =δD 2 +δP 2 +δH 2 The relationship between them.

[0060] The HSP distance between two substances is expressed by setting the δD, δP, and δH of the two substances as (δD1, δP1, δH1) and (δD2, δP2, δH2), respectively, and is represented by the following formula.

[0061] HSP distance = SQRT(4×(δD1-δD2)) 2 +(δP1-δP2) 2 +(δH1-δH2) 2 )

[0062] HSP distance refers to the distance between two points when HSP values ​​are considered as coordinates in three-dimensional space. It is believed that the smaller the HSP distance (the closer the HSP values), the easier it is for the two substances to dissolve.

[0063] The HSP value of a substance can be calculated by inputting its structural formula into HSPiP (Hansen Solubility Parameters in Practice).

[0064] Alternatively, numerical values ​​and literature values ​​from the HSPiP database can be used.

[0065] In addition to these methods, the HSP value can also be determined experimentally.

[0066] The target component is dispersed in a solvent with a known HSP value, and its dispersibility in that specific solvent is evaluated. For dispersibility evaluation, the target component with the desired HSP value is dispersed in the solvent, and the absorption spectrum is measured. The absorbance values ​​are recorded at 10-second intervals over 20 minutes (measurement wavelength: 632 nm). The absorbance at 20 minutes divided by the absorbance at the start of the measurement is calculated as the dispersibility index (DISP). Based on the obtained dispersibility index, the dispersibility in each solvent is evaluated according to the following evaluation criteria.

[0067] 1: DISP=0.30 or more

[0068] 2: DISP = 0.20 or higher and less than 0.30

[0069] 3: DISP = 0.15 or higher and less than 0.20

[0070] 4: DISP = 0.10 or higher and less than 0.15

[0071] 5: DISP = less than 0.10

[0072] The evaluation results of dispersibility in each solvent are input into HSP, thereby enabling the calculation of the HSP value of the target component.

[0073] The solvent used in the above method for determining the HSP value can be any solvent from toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, methyl ethyl ketone (MEK), etc.

[0074] The HSP values ​​of the active material and additives constituting the electrode composition are determined, and the HSP distance between the additives and the active material is determined from the HSP values ​​(more precisely, the δD, δP, and δH of the active material and the additives respectively).

[0075] In the electrode composition of the present invention, the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 the following.

[0076] In addition, the HSP distance between the additive and the active substance is preferably 4.0 MPa. 0.5 above.

[0077] The HSP distance between the additive and the active substance is less than 4.0 MPa. 0.5 In cases where the HSP of the additive and the active material are close, the compatibility between the additive and the active material is high. As a result, the surface of the active material is eroded by the additive, and the electrode layer may become brittle when it is made into an electrode layer.

[0078] Although the electrolyte is not part of the electrode composition, the electrode composition contains the electrolyte and is used as the electrode layer of a secondary battery. The HSP distance between the additive and the electrolyte is determined by the relationship between the additive and the electrolyte contained in the electrode composition.

[0079] Calculate the HSP values ​​for the additive and electrolyte, and then determine the HSP distance between the additive and the electrolyte from the HSP values ​​(more precisely, the δD, δP, and δH values ​​of the additive and electrolyte respectively).

[0080] In the electrode composition of the present invention, the HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

[0081] In addition, the HSP distance between the additive and the electrolyte is preferably 12.0 MPa. 0.5 the following.

[0082] Furthermore, there is no particular limitation on the lower limit of the HSP distance between the additive and the electrolyte; for example, 1.0 MPa is preferred. 0.5 above.

[0083] There are no particular limitations on additives as long as they are compounds that can meet the conditions (2) and (3) related to HSP distance. For specific examples, the following compounds can be cited.

[0084] (A1) Epoxide adducts of alkyl alcohols

[0085] (A2) Epoxide adducts of alkylene glycols

[0086] (A3) Diol ethers

[0087] (A4) Bisphenolic epoxide adducts

[0088] (A5) Ester compounds

[0089] (A6) amine compounds

[0090] (A7) alcohol

[0091] (A1) Epoxide adducts of alkyl alcohols

[0092] The epoxide preferably includes ethylene oxide. Alternatively, the epoxide may also include epoxides other than ethylene oxide. Examples of epoxides other than ethylene oxide include propylene oxide and butane oxide.

[0093] In this specification, alkyl epoxides are sometimes referred to as AO, ethylene oxide as EO, propylene oxide as PO, and butane epoxide as BO.

[0094] Epoxides can be combinations of ethylene oxide and propylene oxide, combinations of ethylene oxide and butane oxide, or combinations of ethylene oxide with propylene oxide and butane oxide.

[0095] When epoxides are composed of multiple epoxides, the addition can take the form of random addition or block addition.

[0096] Based on the total molar number of epoxides, the molar proportion of ethylene oxide in the epoxide is preferably 85% or more.

[0097] Alternatively, alkyl epoxides can consist solely of ethylene oxide. That is, based on the total molar number of alkyl epoxides, the molar proportion of ethylene oxide in an alkyl epoxide can be 100%.

[0098] The molar proportion of ethylene oxide in alkyl oxides can be 85–100%, 87–100%, 92–100%, 85–87%, 85–92%, or 87–92%.

[0099] The average molar number of epoxides added to the alkyl alcohol alkyl oxide adduct is preferably 2 to 40.

[0100] The average number of moles added to epoxides can be 3–20 or 4–10.

[0101] When multiple epoxides are present, the molar number of epoxides added is the sum of the molar numbers of all epoxides added.

[0102] From the perspective of suppressing the degradation of battery performance caused by side reactions that may occur during charging and discharging, the alkyl alcohol constituting the alkyl alcohol epoxide adduct is preferably a saturated alkyl alcohol.

[0103] The alkyl group in alkyl alcohols can be either straight-chain or branched.

[0104] The number of carbon atoms in the alkyl group of an alkyl alcohol is not particularly limited, but is preferably 1 to 20.

[0105] Examples of alkyl alcohols with 1 to 20 carbon atoms include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, 2-ethylhexanol, isodecanol, and isotriadecanol.

[0106] Specific examples of alkyl alcohol alkyl oxide adducts include heptaethylene glycol monoisodecyl ether, tetraethylene glycol monopentadecanyl ether, nonaethylene glycol monododecyl ether, and nonaethylene glycol monomethyl ether.

[0107] (A2) Epoxide adducts of alkylene glycols

[0108] As an epoxide, the same epoxide as (A1) can be used, and the addition forms and combinations of epoxides can also be the same as (A1).

[0109] Based on the total molar number of epoxides, the molar proportion of ethylene oxide in the epoxide is preferably 85% or more.

[0110] Alternatively, alkyl epoxides can consist solely of ethylene oxide. That is, based on the total molar number of alkyl epoxides, the molar proportion of ethylene oxide in an alkyl epoxide can be 100%.

[0111] In addition, the alkylene glycol is preferably ethylene glycol, and more preferably an ethylene oxide adduct of ethylene glycol (polyethylene glycol).

[0112] The average molar number of epoxides added to the alkylene glycol alkylene adduct is preferably 2 to 40.

[0113] The average number of moles added to epoxides can be 3–20 or 4–10.

[0114] Specific examples of alkylene glycols as alkylene glycols include tetraethylene glycol (4 moles of ethylene oxide), octaethylene glycol (8 moles of ethylene oxide), and heptapropylene glycol (7 moles of propylene oxide).

[0115] (A3) Diol ethers

[0116] The alkylene glycol unit in glycol ethers is preferably ethylene glycol or propylene glycol, more preferably ethylene glycol. The number of repetitions of the alkylene glycol unit is preferably 3 to 20, but can also be 4 to 15.

[0117] Specific examples of glycol ethers include triethylene glycol dimethyl ether, hexaethylene glycol tribenzylphenyl ether, and tetradecyl glycol tribenzylphenyl ether.

[0118] (A4) Bisphenolic epoxide adducts

[0119] It is a compound obtained by adding an epoxide to a bisphenol. As an epoxide, the same epoxide as (A1) can be used, and the form and combination of the epoxide addition can also be the same as (A1).

[0120] Examples include the EO adduct of bisphenol A, the PO adduct of bisphenol A, and the BO adduct of bisphenol A.

[0121] The average number of moles added to epoxides can be 1–20 or 1–5.

[0122] Specific examples of bisphenol alkyl oxide adducts include the EO 2 molar adduct of bisphenol A.

[0123] (A5) Ester compounds

[0124] It includes carboxylic acid esters, phosphate esters, etc., and examples include monoesters, diesters, and triesters.

[0125] Specific examples of ester compounds include methyl octanoate, methyl tetradecanoate, glyceryl stearate, and triphosphates (such as tris(2-chloro-1-methylethyl) phosphate).

[0126] (A6) amine compounds

[0127] Examples include saturated cyclic monoamines [e.g., alicyclic amines (monoamines containing cyclic saturated hydrocarbon groups) {e.g., cyclobutamine, cyclopentamine, cyclohexylamine, cycloheptamine, dicyclohexylamine, N-methylcyclohexylamine, trimethylcyclohexylamine, aminomethylcyclohexane, 1-cyclohexylethylamine, etc.}, saturated heterocyclic monoamines {e.g., morpholine, piperidine, etc.}, etc.], unsaturated cyclic monoamines (monoamines containing cyclic unsaturated hydrocarbon groups) [e.g., aromatic amines {e.g., aniline, anisidine, toluidine, trimethylaniline, etc.}, unsaturated heterocyclic monoamines {e.g., pyrrole, acrylonitrile, azirrocyclononazone, etc.}, etc.], etc.

[0128] Cyclohexylamine is a preferred example.

[0129] (A7) alcohol

[0130] Examples include aliphatic alcohols, aromatic alcohols, and aromatic aliphatic alcohols. Aliphatic alcohols are preferred. The number of carbon atoms in the aliphatic group is not particularly limited and can be 1 to 20 or 10 to 20.

[0131] As a specific example of an alcohol, hexadecyl alcohol can be cited.

[0132] Based on the weight of the electrode composition, the content of the additive is preferably 0.001 to 2% by weight. If the content of the additive is within this range, the effect brought about by the presence of the additive can be more appropriately exerted.

[0133] (electrolyte)

[0134] As the electrolyte, an electrolyte for secondary batteries can be used, and preferably an electrolyte containing a non-aqueous solvent suitable for lithium-ion batteries can be used.

[0135] The HSP distance (Ra_Elec) between the electrolyte and the additives contained in the electrode composition is 14.0 MPa. 0.5 The following electrolyte.

[0136] As a solvent contained in the electrolyte, non-aqueous solvents used in known electrolytes can be used, such as lactone compounds, cyclic or chain carbonates, chain carboxylic esters, cyclic or chain ethers, phosphate esters, nitrile compounds, amide compounds, sulfones, sulfolane, and mixtures thereof.

[0137] Examples of lactone compounds include 5-membered ring lactone compounds (such as γ-butyrolactone and γ-valerolactone) and 6-membered ring lactone compounds (such as δ-valerolactone).

[0138] Examples of cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), and butyl carbonate (BC).

[0139] Examples of chain carbonates include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl n-propyl carbonate, ethyl n-propyl carbonate, and di n-propyl carbonate.

[0140] Examples of chain-like carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate.

[0141] Examples of cyclic ethers include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, and 1,4-dioxane. Examples of chain ethers include dimethoxymethane and 1,2-dimethoxyethane.

[0142] Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri(trifluoromethyl) phosphate, tri(trichloromethyl) phosphate, tri(trifluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxophosphacyclopentan-2-one, 2-trifluoroethoxy-1,3,2-dioxophosphacyclopentan-2-one, and 2-methoxyethoxy-1,3,2-dioxophosphacyclopentan-2-one.

[0143] Examples of nitrile compounds include acetonitrile. Examples of amide compounds include DMF. Examples of sulfones include dimethyl sulfone and diethyl sulfone.

[0144] These solvents can be used alone or in combination of two or more.

[0145] As a mixed solvent, the preferred solvents are a mixture of ethylene carbonate and diethyl carbonate; a mixture of ethylene carbonate, methyl ethyl carbonate and diethyl carbonate; or a mixture of ethylene carbonate and propylene carbonate.

[0146] As the electrolyte contained in the electrolyte, known electrolytes used in electrolytes can be used, such as lithium salts of inorganic anions like LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, and LiN(FSO2)2, and lithium salts of organic anions like LiN(CF3SO2)2, LiN(C2F5SO2)2, and LiC(CF3SO2)3. Among these, LiPF6 (lithium hexafluorophosphate) and LiFSI (lithium bis(fluorosulfonyl)imide) are preferred.

[0147] The concentration of the electrolyte in the electrolyte solution is not particularly limited, but is preferably 0.3 to 5.0 mol / L, more preferably 0.5 to 2.0 mol / L, and even more preferably 0.8 to 1.5 mol / L.

[0148] The HSP value of an electrolyte depends primarily on the type of solvent. The HSP value can be determined based on the type of solvent without considering the influence of the electrolyte.

[0149] When using a mixed solvent as the solvent, the average value of each component (δD, δP, and δH) of the HSP value of each solvent, obtained based on the volume ratio of each solvent, is used as the component of the HSP value of the mixed solvent.

[0150] (Adhesive resin)

[0151] The electrode composition of the first embodiment does not contain a binder resin, while the electrode composition of the second embodiment does contain a binder resin. The binder resin will be described below.

[0152] Substances that can be used as additives may include substances known as binder resins, but in this specification, binder resins are referred to as substances distinct from additives.

[0153] Binder resins are resins used in lithium-ion batteries, and examples include starch, polyvinylidene fluoride, polyvinyl alcohol, polyvinylpyrrolidone, polytetrafluoroethylene, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyethylene, and polypropylene.

[0154] When the electrode composition contains these substances, they are used as a binder resin.

[0155] Furthermore, even if the relationship between the HSP distance to the active material and the HSP distance to the electrolyte meets the requirements of this invention, these materials are not included in the additives of this invention.

[0156] Furthermore, the weight-average molecular weight (Mw) of binder resins is mostly greater than 50,000. Based on this, the electrode composition of the first type, which does not contain binder resin, is specified to meet the condition that "(4) the weight-average molecular weight (Mw) of the additive is 50,000 or less".

[0157] The weight-average molecular weight of an additive can be determined based on the additive's structural formula. If determined by measurement, it can be determined by gel permeation chromatography under conditions such as those described below.

[0158] Device: "Waters Alliance 2695" [Made by Waters Corporation]

[0159] Column: "Guardcolumn Super HL" (1 piece), "A column made by connecting 1 each of TSKgel SuperH2000, TSKgel SuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corporation)"

[0160] Sample solution: 0.25% by weight tetrahydrofuran solution

[0161] Solution injection volume: 10 μl

[0162] Flow rate: 0.6 ml / min

[0163] Measurement temperature: 40℃

[0164] Detection device: Refractive index detector

[0165] Reference material: Standard polyethylene glycol

[0166] On the other hand, the electrode composition of the second method specifies that it includes a binder resin, and therefore may contain a substance with a weight-average molecular weight of more than 50,000.

[0167] Based on the weight of the electrode composition, when the electrode composition contains binder resin, the content of binder resin is preferably more than 0% by weight and less than 6.0% by weight.

[0168] The electrode composition of the present invention may contain conductive additives. Examples of conductive additives include metals [aluminum, stainless steel (SUS), silver, gold, copper and titanium, etc.], carbon [graphite (sheet graphite (UP)), carbon black (acetylene black, Ketjen black, furnace black, channel black and thermal lamp black, etc.) and carbon nanofibers (CNF), etc.], and mixtures thereof.

[0169] Acetylene black is preferred as a conductive additive.

[0170] It should be noted that carbon-based materials are used as both negative electrode active materials and conductive additives. However, in this application, materials with a volume average particle size of 10.0 μm or more are considered as negative electrode active materials, and materials with a volume average particle size of less than 10.0 μm are considered as conductive additives.

[0171] The electrode composition of the present invention has an HSP distance of 12.0 MPa between the active material and the additive. 0.5 Therefore, the active material and additives are well integrated, and the surface of the active material is treated with the additives. Furthermore, the HSP distance between the additives and the electrolyte is specified to be 14.0 MPa. 0.5 The additives and electrolyte exhibit a favorable compatibility. Therefore, the electrolyte readily permeates into the electrode composition. Consequently, the electrode composition of the present invention becomes an electrode composition capable of manufacturing electrodes with excellent electrolyte permeability.

[0172] Furthermore, the electrode composition of the present invention exhibits excellent electrolyte permeability even when the electrode density is increased, thus becoming an electrode composition capable of manufacturing high energy density electrodes without reducing production capacity.

[0173] Furthermore, if the HSP distance between the active substance and the additive is 4.0 MPa 0.5 The above constitutes an electrode composition capable of manufacturing electrodes with good properties in terms of electrode brittleness.

[0174] [Electrodes for secondary batteries and secondary batteries]

[0175] The electrode for secondary batteries of the present invention is a secondary battery electrode formed by compression molding of the electrode composition of the present invention.

[0176] As the electrode composition of the present invention, either the electrode composition of the first type or the electrode composition of the second type can be used.

[0177] There is no particular limitation on the method of compression molding the electrode composition; methods such as rolling or pressing with a press can be used. The electrode density of the secondary battery electrode obtained by compression molding the electrode composition is preferably 1.0–2.0 g / cm³. 3 .

[0178] The electrode density specified here refers to the density under conditions where the electrolyte has not permeated into the electrode composition.

[0179] Furthermore, a secondary battery equipped with the electrode for a secondary battery as described above is also a secondary battery of the present invention. In this secondary battery of the present invention, there are no particular limitations on the components other than the electrode for a secondary battery.

[0180] [Rechargeable Battery]

[0181] In addition to the secondary battery having the electrodes for the secondary battery described above, the present invention also includes the secondary battery of the first embodiment and the secondary battery of the second embodiment described below.

[0182] The secondary battery of the first embodiment corresponds to the electrode composition of the first embodiment, and the secondary battery of the second embodiment corresponds to the electrode composition of the second embodiment.

[0183] The secondary battery of the first type is a secondary battery that includes a current collector layer, a secondary battery electrode layer and a separator layer, and is a secondary battery that satisfies all the conditions (1) to (4) below.

[0184] (1) The electrode layer of the above-mentioned secondary battery contains active materials, electrolyte and additives, but does not contain binder resin;

[0185] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0186] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following;

[0187] (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0188] The secondary battery of the second type is a secondary battery that includes a current collector layer, a secondary battery electrode layer and a separator layer, and is a secondary battery that satisfies all the conditions (1) to (3) below.

[0189] (1) The electrode layer of the above-mentioned secondary battery contains active materials, electrolyte, binder resin and additives;

[0190] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0191] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0192] The provisions of (2) to (4) in the secondary batteries of the first and second methods are the same as those in the electrode compositions of the present invention.

[0193] The secondary batteries of the first and second methods have a secondary battery electrode layer. In (1), it is specified that the secondary battery electrode layer contains an electrolyte.

[0194] The secondary battery electrode layer is formed by containing an electrolyte in the electrode compositions of methods 1 and 2. The secondary battery electrode layer has good permeability to the electrolyte in the electrode compositions of methods 1 and 2, thus enabling it to contain a sufficient amount of electrolyte in a short time. Because the secondary battery electrode layer can contain a sufficient amount of electrolyte in a short time, the secondary batteries of methods 1 and 2 are secondary batteries that require short manufacturing times and can extract capacities close to theoretical values.

[0195] The secondary battery, in addition to the electrode layer, consists of a current collector layer and a separator layer. The current collector layer and separator layer can be those commonly used in lithium-ion secondary batteries.

[0196] The secondary battery of the present invention can be used as a secondary battery in mobile phones, personal computers, hybrid vehicles, electric vehicles, stationary power supplies, etc.

[0197] [Electrolyte permeation method]

[0198] The electrolyte permeation method of the present invention includes the following first-mode electrolyte permeation method and second-mode electrolyte permeation method.

[0199] The electrolyte permeation method of the first embodiment corresponds to a method of permeating electrolyte into the electrode composition of the first embodiment, and the electrolyte permeation method of the second embodiment corresponds to a method of permeating electrolyte into the electrode composition of the second embodiment.

[0200] The electrolyte permeation method of the first method is a method of permeating electrolyte into the electrode composition, which is an electrolyte permeation method that satisfies all the conditions (1) to (4) below.

[0201] (1) The above electrode composition contains active substances and additives, but does not contain binder resin;

[0202] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0203] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following;

[0204] (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0205] The second method of electrolyte permeation is a method of permeating electrolyte into the electrode composition, which is an electrolyte permeation method that satisfies all the conditions (1) to (3) below.

[0206] (1) The above electrode composition contains active substances, binder resin and additives;

[0207] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0208] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0209] In any electrolyte permeation method, there is no particular limitation on the means of permeating the electrolyte into the electrode composition; any of the following can be used: a sprayer, a dispenser, a die coater, and a roller coater.

[0210] Alternatively, after assembling the battery components such as the electrode composition, current collector, and separator and sealing them with a sealing member, electrolyte can be injected into the electrode composition through an injection port provided on the sealing member, allowing the electrolyte to permeate into the electrode composition.

[0211] In the electrolyte permeation method of the present invention, since the electrolyte permeability of the electrode composition is good, the operation of permeating the electrolyte into the electrode composition can be carried out in a short time, and the operation is good when obtaining the secondary battery electrode layer.

[0212] The working time (penetration time) for the electrolyte to penetrate into the electrode composition varies depending on the type of electrolyte, the size of the secondary battery, etc., and can be less than 300 minutes.

[0213] [Manufacturing method of secondary batteries]

[0214] The manufacturing method of the secondary battery of the present invention includes the following first method and second method.

[0215] The manufacturing method of the secondary battery of the first embodiment corresponds to the method of manufacturing the secondary battery by permeating the electrolyte into the electrode composition of the first embodiment, and the manufacturing method of the secondary battery of the second embodiment corresponds to the method of manufacturing the secondary battery by permeating the electrolyte into the electrode composition of the second embodiment.

[0216] The manufacturing method of the secondary battery of the first method involves the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the conditions (1) to (4) below.

[0217] (1) The electrode composition layer described above contains active substances and additives, but does not contain binder resin;

[0218] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0219] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following;

[0220] (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0221] The manufacturing method of the secondary battery of the second type involves the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the conditions (1) to (3) below.

[0222] (1) The electrode composition layer described above contains active substances, binder resin and additives;

[0223] (2) The HSP distance (Ra_Act) between the above additive and the above active substance is 12.0 MPa. 0.5 the following;

[0224] (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0225] In any method of manufacturing a secondary battery, there is no particular limitation on the means of permeating the electrolyte into the battery cell containing the electrode composition layer; any one of a sprayer, distributor, die coater, and roller coater may be used.

[0226] When permeating the battery cell with electrolyte, the electrolyte can be permeated into the electrode composition to form a secondary battery electrode layer, and then the current collector layer and the separator layer can be combined to form a battery cell having a secondary battery electrode layer. Alternatively, the current collector layer, the electrode composition layer, and the separator layer can be combined, and then the electrolyte can be permeated into the electrode composition layer to form a secondary battery electrode layer, thus forming a battery cell having a secondary battery electrode layer.

[0227] In the manufacturing method of the secondary battery of the present invention, since the electrolyte permeability of the electrode composition is good, the operation of permeating the electrolyte into the electrode composition can be carried out in a short time, and the operation of obtaining the electrode layer of the secondary battery is good.

[0228] The working time (penetration time) for the electrolyte to penetrate into the electrode composition varies depending on the type of electrolyte, the size of the secondary battery, etc., and can be less than 300 minutes.

[0229] The following information is disclosed in this specification.

[0230] This disclosure (1) is an electrode composition for use in a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the conditions (1) to (4) below. (1) It contains an active substance and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0231] This disclosure (2) is an electrode composition for use in a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the conditions (1) to (3) below. (1) It contains an active substance, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0232] This disclosure (3) is the electrode composition described in disclosure (1) or (2), wherein the HSP distance (Ra_Act) between the additive and the active material is 4.0 MPa. 0.5 above.

[0233] This disclosure (4) is the electrode composition described in any one of disclosures (1) to (3), wherein the HSP distance (Ra_Elec) between the additive and the electrolyte is 12.0 MPa. 0.5 the following.

[0234] This disclosure (5) is the electrode composition described in any one of (1) to (4) of this disclosure, wherein the additive is an alkylene oxide adduct of an alkyl alcohol or an alkylene glycol alkylene oxide adduct.

[0235] This disclosure (6) is the electrode composition described in this disclosure (5), wherein the alkyl alcohol is a saturated alkyl alcohol.

[0236] This disclosure (7) is the electrode composition of any one of disclosures (1) to (6), wherein the active material is selected from at least one of the group consisting of a composite oxide containing at least one transition metal element, artificial graphite and natural graphite.

[0237] This disclosure (8) is the electrode composition described in any one of disclosures (1) to (7), wherein the solvent of the electrolyte is a mixed solvent of ethylene carbonate and diethyl carbonate; a mixed solvent of ethylene carbonate, methyl ethyl carbonate and diethyl carbonate; or a mixed solvent of ethylene carbonate and propylene carbonate.

[0238] This disclosure (9) is an electrode for a secondary battery, which is formed by compressing the electrode composition described in any one of disclosures (1) to (8).

[0239] This disclosure (10) is a secondary battery having the electrodes for a secondary battery described in this disclosure (9).

[0240] This disclosure (11) is a secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (4): (1) The secondary battery electrode layer contains an active material, an electrolyte, and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0241] This disclosure (12) is a secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (3): (1) The secondary battery electrode layer contains an active material, an electrolyte, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0242] This disclosure (13) is an electrolyte permeation method, which is a method for permeating an electrolyte into an electrode composition, wherein the electrolyte permeation method satisfies all of the following conditions (1) to (4). (1) The electrode composition contains an active substance and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa.0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0243] This disclosure (14) is an electrolyte permeation method, which is a method for permeating an electrolyte into an electrode composition, wherein the electrolyte permeation method satisfies all of the following conditions (1) to (3): (1) The electrode composition contains an active substance, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active substance is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0244] This disclosure (15) is a method for manufacturing a secondary battery, which includes the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the following conditions (1) to (4). (1) The electrode composition layer contains an active material and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 The following; (4) The weight average molecular weight (Mw) of the above additives is less than 50,000.

[0245] This disclosure (16) is a method for manufacturing a secondary battery, which includes the following steps: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the manufacturing method of the secondary battery satisfies all of the following conditions (1) to (3): (1) The electrode composition layer contains an active material, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following; (3) The HSP distance (Ra_Elec) between the above additive and the above electrolyte is 14.0 MPa. 0.5 the following.

[0246] Example

[0247] Next, the present invention will be specifically described through embodiments, but the present invention is not limited to the embodiments as long as it does not depart from the spirit of the invention. It should be noted that, unless otherwise specified, parts refer to parts by weight, and % refers to percentages by weight.

[0248] (Preparation of Additives 1-21)

[0249] Prepare the following additives 1 to 21.

[0250] (Additive 1)

[0251] Methyl octanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 1.

[0252] (Additive 2)

[0253] Methyl tetradecanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 2.

[0254] (Additive 3)

[0255] Glycerol and stearic acid (molar ratio: 1 / 1) were added to xylene to initiate an esterification reaction (xylene content: 50 wt%). Polymerization was carried out under reflux, removing the water generated during the esterification reaction along with the xylene. The removed xylene was added in addition to the xylene, and the reaction continued until no more water was generated. After the reaction, the xylene was removed using a vacuum dryer to obtain solid glycerol stearate as additive 3.

[0256] (Additive 4)

[0257] An alkyl alkyl oxide adduct of an alkyl alcohol, prepared by adding ethylene oxide (EO) to isodecanol, is used as additive 4.

[0258] The average molar number of EO additions is 7.0, and the compound is named heptaethylene glycol monoisodecyl ether.

[0259] (Additive 5)

[0260] An alkyl alkyl adduct of an alkyl alcohol, obtained by adding ethylene oxide (EO) to pentadecanol, is used as additive 5.

[0261] The average molar addition of EO is 4.0, and the compound is named tetraethylene glycol monopentadecanyl ether.

[0262] (Additive 6)

[0263] An alkyl alkyl oxide adduct of an alkyl alcohol, obtained by adding ethylene oxide (EO) to dodecyl alcohol, is used as additive 6.

[0264] The average molar addition of EO is 9.0, and the compound is named nonaethylene glycol monododecyl ether.

[0265] (Additive 7)

[0266] Tetraethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 7.

[0267] (Additive 8)

[0268] Octaethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 8.

[0269] (Additive 9)

[0270] An alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to methanol was obtained as an additive 9.

[0271] The average molar addition of EO is 9.0, and the compound is named nonaethylene glycol monomethyl ether.

[0272] (Additive 10)

[0273] Triethylene glycol dimethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 10.

[0274] (Additive 11)

[0275] An alkyl alkyl oxide adduct of an alkyl alcohol, prepared by adding ethylene oxide (EO) to tribenzylphenol, is obtained as additive 11.

[0276] The average molar addition of EO is 6.0, and the compound is named hexaethylene glycol tribenzylphenyl ether.

[0277] (Additive 12)

[0278] An alkyl alkyl oxide adduct of an alkyl alcohol, prepared by adding ethylene oxide (EO) to tribenzylphenol, was obtained as additive 12.

[0279] The average molar addition of EO is 14.0, and the compound is named tetradecyl glycol tribenzylphenyl ether.

[0280] (Additive 13)

[0281] Cyclohexylamine (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 13.

[0282] (Additive 14)

[0283] An alkyl alkyl oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to bisphenol A was obtained as an additive 14.

[0284] The average molar addition of EO is 2.0, and the compound is named Bisphenol A EO 2 molar adduct.

[0285] (Additive 15)

[0286] Tris(2-chloro-1-methylethyl) phosphate (reagent: manufactured by Fujifilm and Kohden Chemical Co., Ltd.) was used as additive 15.

[0287] (Additive 16)

[0288] An alkyl alkyl adduct of an alkyl alcohol, which is produced by adding propylene oxide (PO) to propylene glycol, is used as additive 16.

[0289] The average number of moles of PO added is 6.0, and the compound is named heptapropylene glycol.

[0290] (Additive 17)

[0291] Cetyl alcohol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 17.

[0292] (Additive 18)

[0293] Triethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 18.

[0294] (Additive 19)

[0295] Ethylene glycol monomethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as an additive 19.

[0296] (Additive 20)

[0297] Trimethylolpropane (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 20.

[0298] (Additive 21)

[0299] N-(hydroxymethyl)methacrylamide (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 21.

[0300] (Preparation of electrolytes 1-4)

[0301] All the substances prepared below are reagents (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0302] (Electrolyte 1)

[0303] Ethyl carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of EC:DEC = 1:1 to dissolve lithium hexafluorophosphate (LIPF6) at a concentration of 1 M. The resulting solution was used as electrolyte 1.

[0304] (Electrolyte 2)

[0305] Ethyl carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC = 2:4:4 to dissolve lithium hexafluorophosphate (LIPF6) at 1 M. The resulting solution was used as electrolyte 2.

[0306] (Electrolyte 3)

[0307] Ethyl carbonate (EC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC = 3:5:2 to dissolve lithium hexafluorophosphate (LIPF6) at 1 M. The resulting solution was used as electrolyte 3.

[0308] (Electrolyte 4)

[0309] Ethyl carbonate (EC) and propylene carbonate (PC) were mixed at a volume ratio of EC:PC = 1:1 to dissolve lithium hexafluorophosphate (LIPF6) at 1 M. The resulting solution was used as electrolyte 4.

[0310] (Preparation of negative electrode active material)

[0311] Prepare the following negative electrode active material.

[0312] Graphite 1: Artificial graphite (FSN-1, made by China Shanshan, volume average particle size (D50): 15.3 μm)

[0313] Graphite 2: Spherical graphite (CGR 12R, manufactured by Nippon Graphite Industries, Ltd., volume average particle size: 10.6 μm)

[0314] (Calculation of HSP value of negative electrode active material: graphite 1)

[0315] The dispersibility of graphite 1 in various solvents was evaluated using the following methods.

[0316] 20 mL of a solvent with known solubility parameters and 0.04 g of graphite 1 were added to a No. 7 threaded tube manufactured by Maruemu. A stir bar was added, and the mixture was stirred at 400 rpm for 30 minutes to prepare a suspension. The suspension was then allowed to stand in a constant temperature bath at 25°C for 12 hours to prepare a dispersion for assay.

[0317] Solvents with known solubility parameters include toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, and methyl ethyl ketone (MEK).

[0318] The solubility parameters of these solvents are referenced from the HSPiP database.

[0319] In addition, 20 mL of each solvent was taken from a No. 7 threaded tube made by Maruemu and placed in a constant temperature bath at 25°C for 12 hours as a reference solvent.

[0320] Baseline measurements were performed using a UV-Vis-NIR spectrophotometer (UV-3600i Plus, Shimadzu Corporation) with a reference solvent. Then, the analyte dispersion corresponding to the reference solvent was stirred in a threaded tube for at least 1 minute. While maintaining full dispersion, 1000 μL was transferred four times using a micropipette to a quartz cell equipped with a stir bar, which served as the measurement cell. The measurement cell was placed on a stand with a stirrer, and stirring was performed for 30 seconds. Simultaneously, the absorption spectrum was measured, and absorbance values ​​were recorded at 10-second intervals over 20 minutes (measurement wavelength: 632 nm).

[0321] The absorbance at 20 minutes (A20) / absorbance at the start of the measurement (A0) is calculated as the dispersion index (DISP). The dispersibility in each solvent is evaluated based on the following criteria using the obtained dispersion index.

[0322] (Evaluation Criteria)

[0323] 1: DISP=0.30 or above

[0324] 2: DISP = 0.20 or higher and less than 0.30

[0325] 3: DISP = 0.15 or higher and less than 0.20

[0326] 4: DISP = 0.10 or higher and less than 0.15

[0327] 5: DISP = less than 0.10

[0328] Based on the evaluation results of the dispersibility of graphite 1 in the solvent, the HSP value of graphite 1 was calculated by inputting HSP. The evaluation results of dispersibility used in the calculation of the HSP value of graphite 1 are shown in Table 1.

[0329] [Table 1]

[0330] Toluene 18.0 1.4 2.0 0.33 1 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.31 1 diethyl carbonate 15.1 6.3 3.5 0.15 3 dimethylformamide 17.4 13.7 11.3 0.15 3 1,4-Dioxane 17.5 1.8 9.0 0.12 4 hexane 14.9 0.0 0.0 0.12 4 Cyclohexane 16.8 0.0 0.2 0.11 4 methanol 14.7 12.3 22.3 0.11 4 ethanol 15.8 8.8 19.4 0.09 5 acetone 15.5 10.4 7.0 0.07 5 Acetonitrile 15.3 18.0 6.1 0.07 5 Methyl ethyl ketone (MEK) 16.0 9.0 5.1 0.04 5

[0331] (Calculation of HSP value of negative electrode active material: graphite 2)

[0332] For graphite 2, the HSP value was calculated in the same manner as for graphite 1. Instead of using hexane, a solvent with known solubility parameters used in the calculation of the HSP value for graphite 1, a different solvent was used. The remaining steps were the same as for graphite 1.

[0333] The evaluation results of the dispersibility used in the calculation of the HSP value of graphite 2 are shown in Table 2.

[0334] [Table 2]

[0335] Toluene 18.0 1.4 2.0 0.54 1 Cyclohexane 16.8 0.0 0.2 0.46 1 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.42 1 1,4-Dioxane 17.5 1.8 9.0 0.10 4 ethanol 15.8 8.8 19.4 0.09 5 diethyl carbonate 15.1 6.3 3.5 0.08 5 methanol 14.7 12.3 22.3 0.07 5 acetone 15.5 10.4 7.0 0.06 5 dimethylformamide 17.4 13.7 11.3 0.05 5 Acetonitrile 15.3 18.0 6.1 0.03 5 Methyl ethyl ketone (MEK) 16.0 9.0 5.1 0.03 5

[0336] (Preparation of the positive electrode active material)

[0337] Prepare the following positive electrode active material.

[0338] NCM: NCM811 RL-08-D3 (manufactured by Umicore)

[0339] The composition is LiNi 0.8 Co 0.1 Mn 0.1 O2

[0340] (Calculation of the HSP value of the positive electrode active material: NCM)

[0341] For NCM as the positive electrode active material, the HSP value is calculated in the same manner as for graphite 1.

[0342] The evaluation results of the dispersibility used in the calculation of the HSP value of NCM are shown in Table 3.

[0343] [Table 3]

[0344] Toluene 18.0 1.4 2.0 0.57 1 hexane 14.9 0.0 0.0 0.50 1 Cyclohexane 16.8 0.0 0.2 0.45 1 1,4-Dioxane 17.5 1.8 9.0 0.26 2 methanol 14.7 12.3 22.3 0.23 2 ethanol 15.8 8.8 19.4 0.16 3 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.16 3 dimethylformamide 17.4 13.7 11.3 0.07 5 diethyl carbonate 15.1 6.3 3.5 0.04 5 acetone 15.5 10.4 7.0 0.03 5 Acetonitrile 15.3 18.0 6.1 0.02 5 Methyl ethyl ketone (MEK) 16.0 9.0 5.1 0.00 5

[0345] The solubility parameters of graphite 1, graphite 2, and NCM obtained based on the results shown in Tables 1, 2, and 3 above are shown in Table 4.

[0346] [Table 4]

[0347] Graphite 1 19.0 6.8 4.7 Graphite 2 20.0 5.8 2.6 NCM 16.5 0.4 0.9

[0348] (Examples 1 to 55, Comparative Examples 1 to 39, using graphite 1)

[0349] (Production of the negative electrode with an additive)

[0350] [[ID=​​Next, 3.0 parts by weight of SBR (styrene-butadiene rubber) as a binder resin were added, and the mixture was stirred at 2000 rpm for 5 minutes using a defoaming agent. To the resulting dispersion, 91.0 parts by weight of graphite (as the negative electrode active material), 1.0 parts by weight of additives, and 60.0 parts by weight of deionized water were added, and the mixture was stirred at 2000 rpm for 5 minutes using a defoaming agent to prepare a slurry for the negative electrode active material layer.

[0352] The obtained negative electrode active material layer was coated onto one side of the current collector (copper foil) using a coater with a gap set to 150 μm in atmospheric air. After pre-drying overnight in a ventilated device, it was further dried at 100°C for 2 hours under reduced pressure (1.3 kPa) to obtain the electrode sheet. The electrode sheet was then punched into 16 pieces near its center. The electrodes were prepared by repeating this operation multiple times. Three of the resulting electrodes were used as negative electrodes for a simple electrode brittleness test. The remaining electrodes were pressed twice at 1.5 MPa for 3 seconds each time to prepare evaluation electrodes (negative electrodes). Negative electrodes for additives 1 to 21 were prepared.

[0353] (Preparation of an additive-free negative electrode)

[0354] Graphite 1 was prepared in a weight of 92.0 parts, without any additives. Otherwise, the electrode for simple electrode brittleness test (negative electrode) and the evaluation electrode (negative electrode) were prepared in the same manner as the negative electrode with additives.

[0355] <Calculation of Electrode Density>

[0356] The weight and thickness of the current collector and the evaluation electrode were measured after being pressed twice for 3 seconds at 1.5 MPa using a press, and the electrode density was calculated using the following formula.

[0357] Electrode density (g / cm³) 3 = (Evaluation electrode weight (g) - Current collector weight (μg) × 10 -3 ) / (0.8 2 ×3.14×((Electrode thickness for evaluation (μm)-Currentr thickness (μm))×10 -4 ))

[0358] <Simple Test for Electrode Brittleness>

[0359] The electrode used in the simplified electrode brittleness test was dropped freely from a height of 30 cm onto white paper. This operation was performed on three electrodes used in the simplified electrode brittleness test, and they were evaluated according to the following criteria.

[0360] 〇: There are 0 cases where the electrode sheet is attached to the white paper.

[0361] ×: There is more than one electrode attached to the white paper.

[0362] Electrolyte Permeation Test

[0363] Among the electrodes used for evaluation, the electrode density (g / cm³) is considered. 3 The difference between the maximum and minimum values ​​is 0.03 (g / cm³). 3 Three electrodes were selected in a manner within 1000°C, and their arithmetic mean was recorded as the electrode density (g / cm³) for the evaluation electrodes. 3 ).

[0364] Place a stainless steel M3 flat washer (manufactured by ESCO) at the center of each electrode, and put 20 μL of electrolyte into the hole of the washer. Record the time from when the droplet in the washer completely disappears from the electrode surface in 1 second, and take the arithmetic mean as the electrolyte penetration time (penetration rate: minutes).

[0365] Electrolyte permeation tests were conducted on electrolytes 1 to 4 respectively.

[0366] <Capacity retention rate after harsh testing>

[0367] Fabrication of negative electrode half-cells for stringent capacity retention tests

[0368] Among the electrodes used for evaluation, the electrode density (g / cm³) is considered. 3 The difference between the maximum and minimum values ​​is 0.03 (g / cm³). 3 Three electrodes were selected in a manner within 1000°C, and their arithmetic mean was recorded as the electrode density (g / cm³) for the evaluation electrodes. 3 ).

[0369] The negative electrode, separator [trade name "#3501", manufactured by Celgard], and lithium foil are stacked sequentially from the negative electrode side. After injecting electrolyte, vacuum lamination is performed to prevent oxygen from entering, thus producing a negative electrode half-cell for demanding capacity retention tests.

[0370] Negative half-cell charge and discharge test

[0371] At 25°C, the capacity retention of the negative electrode half-cell for harsh testing was evaluated using the charge-discharge test device "HJ-SD8" [manufactured by Hokuto Denko Co., Ltd.] by the following method.

[0372] Charge to 0V using constant current charging (also known as CC mode) at a current of 0.05C, stop for 10 minutes, and then discharge to 1.5V using a current of 0.05C.

[0373] The discharge capacity at this time is taken as [1 cycle discharge capacity (mAh)].

[0374] Under the same conditions, charge and discharge again, and the discharge capacity at this time is taken as [2-cycle discharge capacity (mAh)].

[0375] Next, charge to 0V with a current of 0.1C, stop for 10 minutes, and then discharge to 1.5V with a current of 0.1C.

[0376] The discharge capacity at this time is taken as [3-cycle discharge capacity (mAh)].

[0377] Then, it is charged to 0V with a current of 0.5C, stopped for 10 minutes, and then discharged to 1.5V with a current of 0.1C.

[0378] The discharge capacity at this time is taken as [4-cycle discharge capacity (mAh)].

[0379] Finally, charge to 0V with a current of 1.0C, stop for 10 minutes, and then discharge to 1.5V with a current of 0.1C.

[0380] The discharge capacity at this time is taken as [5-cycle discharge capacity (mAh)].

[0381] The capacity retention rate after the harsh test was calculated for each of the three electrodes using the following formula, and the arithmetic mean of the calculated rate was taken as the capacity retention rate (%) of the evaluation electrode after the harsh test.

[0382] Capacity retention rate (%) after harsh testing = [5-cycle discharge capacity (mAh)] / [2-cycle discharge capacity (mAh)]

[0383] Electrolyte permeation tests were conducted on Examples 1-17, which used additives 1-17, Comparative Examples 1-4, which did not use additives, and Comparative Examples 5-8, which used additives 18-21.

[0384] The evaluation results using graphite 1 are summarized in Tables 5-12.

[0385] Tables 5 and 6 are examples and comparative examples using electrolyte 1, Tables 7 and 8 are examples and comparative examples using electrolyte 2, Tables 9 and 10 are examples and comparative examples using electrolyte 3, and Tables 11 and 12 are examples and comparative examples using electrolyte 4.

[0386] It should be noted that the units for HSP distances in the tables below are [MPa]. 0.5 ].

[0387]

[0388]

[0389]

[0390]

[0391]

[0392]

[0393]

[0394]

[0395] (Examples 56-106, Comparative Examples 40-82, Using Graphite 2)

[0396] Graphite 2 was used instead of graphite 1 to fabricate negative electrodes with and without additives. Electrode density calculations, simplified electrode brittleness tests, and electrolyte permeation tests were performed. Capacity retention was tested without conducting harsh tests.

[0397] The evaluation results using graphite 2 are summarized in Tables 13-20.

[0398] Tables 13 and 14 are examples and comparative examples using electrolyte 1, Tables 15 and 16 are examples and comparative examples using electrolyte 2, Tables 17 and 18 are examples and comparative examples using electrolyte 3, and Tables 19 and 20 are examples and comparative examples using electrolyte 4.

[0399]

[0400]

[0401]

[0402]

[0403]

[0404]

[0405]

[0406]

[0407] (Examples 107-149, Comparative Examples 83-133, using NCM)

[0408] (The production of a positive electrode with additives)

[0409] 1.0 part by weight of additive and 100.0 part by weight of N-methyl-2-pyrrolidone (NMP) were mixed at 2000 rpm for 5 minutes using a planetary mixing apparatus {Defoaming Rentaro [manufactured by THINKY Co., Ltd.]}. Next, 3.0 parts by weight of polyvinylidene fluoride (manufactured by Kishida Chemical) as a binder resin were added, and the mixture was stirred at 2000 rpm for 5 minutes using the Defoaming Rentaro apparatus.

[0410] After adding 89.0 parts by weight of NCM as the positive electrode active material and 7.0 parts by weight of AB {acetylene black: "DENKA BLACK Li100", manufactured by Denka Co., Ltd. as a conductive additive, the mixture was stirred at 2000 rpm for 4 minutes using a defoaming agent to prepare a slurry for the positive electrode active material layer.

[0411] The obtained positive electrode active material layer was coated onto one side of the current collector (aluminum foil, manufactured by Hosen Co., Ltd.) using a coater with a gap set to 150 μm in atmospheric air. After pre-drying overnight in a ventilated device, it was further dried at 100°C for 2 hours under reduced pressure (1.3 kPa) to obtain the electrode sheet. The electrode sheet was then punched into 16 pieces near the center. The electrodes were prepared by repeating this operation multiple times. Three of the resulting electrodes were used as positive electrodes for a simplified electrode brittleness test. The remaining electrodes were pressed twice at 4.0 MPa for 3 seconds each time to prepare evaluation electrodes (positive electrodes). Positive electrodes were prepared for additives 1 to 21.

[0412] (Preparation of an additive-free positive electrode)

[0413] The electrode (positive electrode) for simple electrode brittleness testing and the electrode (positive electrode) for evaluation were made in the same manner as the positive electrode with additives, with NCM content of 90.0 parts by weight and no additives.

[0414] For the electrode used in the simplified electrode fragility test (positive electrode) and the evaluation electrode (positive electrode), the same procedures as for the negative electrode are followed, including electrode density calculation, simplified electrode fragility test, and electrolyte permeation test. Capacity retention test is performed without conducting the harshness test.

[0415] It should be noted that when calculating electrode density, the calculation formula is modified accordingly based on the different punching diameters of the electrode sheets.

[0416] The evaluation results using NCM are summarized in Tables 21-28.

[0417] Tables 21 and 22 are examples and comparative examples using electrolyte 1, Tables 23 and 24 are examples and comparative examples using electrolyte 2, Tables 25 and 26 are examples and comparative examples using electrolyte 3, and Tables 27 and 28 are examples and comparative examples using electrolyte 4.

[0418]

[0419]

[0420]

[0421]

[0422]

[0423]

[0424] [Table 27]

[0425] Types of additives Additive 8 Types of electrode active materials NCM HSP distance between active substances and additives 11.9 Types of electrolytes Electrolyte 4 HSP distance between electrolyte and additive 13.5 Electrode brittleness 〇 <![CDATA[Electrode density, g / cm 3 > 3.04 Permeation rate, min 129

[0426]

[0427] Based on these results, in electrodes using the same active material and electrolyte, the permeation rates in the embodiments where the HSP distance between the active material and the additive, and the HSP distance between the electrolyte and the additive, were within the specified ranges were faster than those in the comparative examples (shorter permeation times).

[0428] Furthermore, regarding electrode density, the comparative examples varied the electrode density over a relatively wide range (for example, in Comparative Examples 1 to 4, the electrode density varied from 1.53 to 1.64), and the permeation rate in each example was faster than any result of the comparative examples. This demonstrates that, regardless of the electrode density, the permeability of the electrolyte is excellent by satisfying the conditions of the present invention.

[0429] In addition, in Examples 1 to 17, the battery performance of additives 1 to 17, which are effective in improving permeability, was confirmed (harsh test), and none of them had an adverse effect on the battery performance.

[0430] In addition, the HSP distance between the active substance and the additive is less than 4.0 MPa. 0.5 In the examples (Examples 11, 12, etc.), the additives have high compatibility with the active material, so the surface of the active material is eroded by the additives, and the electrode brittleness is rated as ×.

Claims

1. An electrode composition for use in a secondary battery electrode layer containing an electrolyte, wherein, The electrode composition satisfies all of the following conditions (1) to (4): (1) Contains active substances and additives, but does not contain binder resin; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following; (4) The weight average molecular weight Mw of the additive is less than 50,000.

2. An electrode composition for use in a secondary battery electrode layer containing an electrolyte, wherein, The electrode composition satisfies all of the following conditions (1) to (3): (1) Contains active substances, binder resins and additives; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

3. The electrode composition according to claim 1 or 2, wherein, The HSP distance Ra_Act between the additive and the active substance is 4.0 MPa. 0.5 above.

4. The electrode composition according to claim 1 or 2, wherein, The HSP distance Ra_Elec between the additive and the electrolyte is 12.0 MPa. 0.5 the following.

5. The electrode composition according to claim 1 or 2, wherein, The additive is an alkylene oxide adduct of an alkyl alcohol or an alkylene glycol alkylene adduct.

6. The electrode composition of claim 5, wherein, The alkyl alcohol is a saturated alkyl alcohol.

7. The electrode composition according to claim 1 or 2, wherein, The active substance is selected from at least one of the following groups: composite oxides containing at least one transition metal element, artificial graphite, and natural graphite.

8. The electrode composition according to claim 1 or 2, wherein, The solvent of the electrolyte is a mixed solvent of ethylene carbonate and diethyl carbonate; a mixed solvent of ethylene carbonate, methyl ethyl carbonate and diethyl carbonate; or a mixed solvent of ethylene carbonate and propylene carbonate.

9. An electrode for a secondary battery, which is formed by compression molding of the electrode composition according to claim 1 or 2.

10. A secondary battery comprising the electrode for a secondary battery as described in claim 9.

11. A secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein, The secondary battery satisfies all of the following conditions (1) to (4): (1) The electrode layer of the secondary battery contains active materials, electrolyte and additives, but does not contain binder resin; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following; (4) The weight average molecular weight Mw of the additive is less than 50,000.

12. A secondary battery comprising a current collector layer, a secondary battery electrode layer, and a separator layer, wherein, The secondary battery satisfies all of the following conditions (1) to (3): (1) The electrode layer of the secondary battery contains active materials, electrolyte, binder resin and additives; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

13. An electrolyte permeation method, which is a method for permeating an electrolyte into an electrode composition, wherein, The electrolyte permeation method satisfies all of the following conditions (1) to (4): (1) The electrode composition contains active substances and additives, but does not contain binder resin; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following; (4) The weight average molecular weight Mw of the additive is less than 50,000.

14. An electrolyte permeation method, which is a method for permeating an electrolyte into an electrode composition, wherein, The electrolyte permeation method satisfies all of the following conditions (1) to (3): (1) The electrode composition contains active substances, binder resin and additives; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

15. A method for manufacturing a secondary battery, comprising the steps of: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer, to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein, The manufacturing method of this secondary battery satisfies all of the following conditions (1) to (4): (1) The electrode composition layer contains active substances and additives, but does not contain binder resin; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following; (4) The weight average molecular weight Mw of the additive is less than 50,000.

16. A method for manufacturing a secondary battery, comprising the steps of: permeating an electrolyte into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer, to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein, The manufacturing method of this secondary battery satisfies all of the following conditions (1) to (3): (1) The electrode composition layer contains active substances, binder resin and additives; (2) The HSP distance Ra_Act between the additive and the active substance is 12.0 MPa. 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa. 0.5 the following.

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