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

Abstract

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

Description

[Technical Field]

[0001] The present invention relates to an electrode composition, an electrode for a secondary battery, a secondary battery, an electrolyte penetration method, and a method for producing a secondary battery. [Background technology]

[0002] Secondary batteries such as lithium-ion batteries are being used in practical applications such as mobile phones, laptop computers, and other portable devices, as well as in hybrid and electric vehicles. To further popularize these devices, there is a demand for higher capacity and power output secondary batteries, and various technologies are being developed to address this demand.

[0003] One way to improve the capacity of secondary batteries is to increase electrode density. By densely packing the active material, more capacity can be obtained. However, increasing electrode density makes it difficult for the electrolyte to penetrate the electrode, resulting in problems such as less capacity than the theoretical value and a deterioration in output characteristics.

[0004] To solve these problems, Patent Document 1 discloses a technique for improving electrolyte permeability by providing grooves on the electrode surface. Patent Document 2 discloses a technique for improving electrolyte permeability by adjusting 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-27633 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-151088 [Patent Document 3] Japanese Patent Publication No. 2020-053282 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the method of Patent Document 1 involves a step of pressing the electrode surface with a roller having irregularities to form grooves on the surface, which necessitates the introduction of new equipment, which is a problem. Furthermore, although the methods of Patent Documents 2 and 3 show some improvement in permeability, the effect is not sufficient.

[0007] The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrode composition that can be used to produce an electrode having excellent electrolyte permeability. [Means for solving the problem]

[0008] The present inventors have made extensive studies and arrived at the present invention. The present invention relates to any of the following: An electrode composition for a secondary battery electrode layer containing an electrolytic solution, the electrode composition satisfying all of the following (1) to (4): (1) containing an active material and an additive, but not containing a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0009] An electrode composition for a secondary battery electrode layer containing an electrolytic solution, the electrode composition satisfying all of the following (1) to (3): (1) containing 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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result.

[0010] An electrode for a secondary battery is obtained by compression molding the electrode composition. A secondary battery comprising the secondary battery electrode.

[0011] A secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, which satisfies all of the following (1) to (4): (1) the secondary battery electrode layer contains an active material, an electrolyte solution, and an additive, but does not contain a binder resin; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0012] A secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, which satisfies all of the following (1) to (3): (1) the secondary battery electrode layer contains an active material, an electrolyte, a binder resin, and an additive; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result.

[0013] A method for permeating an electrode composition with an electrolyte, the method satisfying all of the following (1) to (4): (1) the electrode composition contains an active material and an additive, but does not contain a binder resin; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0014] A method for permeating an electrode composition with an electrolyte, the method satisfying all of the following (1) to (3): (1) the electrode composition 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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5The following is the result.

[0015] A method for producing a secondary battery, comprising a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, wherein the method satisfies all of the following (1) to (4): (1) the electrode composition layer contains an active material and an additive, but does not contain a binder resin; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0016] A method for producing a secondary battery, comprising a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, wherein the method satisfies all of the following (1) to (3): (1) the electrode composition layer contains an active material, a binder resin, and an additive; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide an electrode composition that can be used to produce an electrode having excellent electrolyte permeability. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Electrode composition] The electrode composition of the present invention includes a first type of electrode composition and a second type of electrode composition. The electrode composition of the first embodiment is an electrode composition for a secondary battery electrode layer containing an electrolytic solution, and is an electrode composition that satisfies all of the following (1) to (4). (1) Contains active materials and additives but does not contain binder resins; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 Below is; (4) The weight average molecular weight (Mw) of the additive is 50,000 or less.

[0019] The electrode composition of the second embodiment is an electrode composition for a secondary battery electrode layer containing an electrolytic solution, and is an electrode composition that satisfies all of the following (1) to (3). (1) 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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 The following is the result.

[0020] The electrode composition of the first embodiment and the electrode composition of the second embodiment differ in the following respects, but are common in other respects. The electrode composition of the first type does not contain a binder resin in (1). The electrode composition of the second type contains a binder resin in (1). The electrode composition of the first type is stipulated to have the weight average molecular weight (Mw) of the additive (4) of 50,000 or less, but the electrode composition of the second type does not have this requirement. Hereinafter, matters common to the electrode compositions of the first and second embodiments will be described.

[0021] The electrode composition of the present invention is an electrode composition for a secondary battery electrode layer containing an electrolytic solution. The electrode composition of the present invention does not itself contain an electrolytic solution, but by adding an electrolytic solution to the electrode composition, it can be used as an electrode layer for a secondary battery. The electrode composition contains an active material and an additive.

[0022] (active material) The active material may be a positive electrode active material or a negative electrode active material.

[0023] The positive electrode active material may be a composite oxide of lithium and a transition metal {composite oxides containing one type of transition metal (e.g., LiCoO2, LiNiO2, LiAlMnO4, LiMnO2, and LiMn2O4), composite oxides containing two types of 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 different transition metal elements, and 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 O2), etc.}, lithium-containing transition metal phosphates (for example, LiFePO4, LiCoPO4, LiMnPO4, and LiNiPO4), transition metal oxides (for example, MnO2 and V2O5), transition metal sulfides (for example, MoS2 and TiS2), and conductive polymers (for example, polyaniline, polypyrrole, polythiophene, polyacetylene, poly-p-phenylene, and polyvinylcarbazole), and two or more of them may be used in combination. The lithium-containing transition metal phosphate may have some of the transition metal sites substituted with other transition metals.

[0024] Examples of the negative electrode active material include carbon-based materials [graphite (graphite, artificial graphite, natural graphite), non-graphitizable carbon (hard carbon), amorphous carbon, burned resins (e.g., phenolic resins, furan resins, etc., which are burned and carbonized), cokes (e.g., pitch coke, needle coke, petroleum coke, etc.), and carbon fibers], silicon-based materials [silicon, silicon oxide (SiO x ), silicon-carbon composites (carbon particles whose surfaces are coated with silicon and / or silicon carbide, silicon particles or silicon oxide particles whose surfaces are coated 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, silicon-tin alloys, etc.), conductive polymers (e.g., polyacetylene and polypyrrole), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxide, etc.) and metal alloys (e.g., lithium-tin alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.), and mixtures of these with carbon-based materials. When the electrode active material is a negative electrode active material, the negative electrode active material is preferably artificial graphite or natural graphite. When the negative electrode active material is graphite, the shape thereof is not particularly limited, and examples thereof include spherical graphite and scaly graphite.

[0025] The content of the active material in the electrode composition is not particularly limited, but from the viewpoint of increasing the electrode density and battery capacity, a high content of the active material is preferred, and is preferably 90 to 95% by weight.

[0026] (additives) The additive is a compound that satisfies the following conditions: (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 The following is the result. (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. 0.5 The following is the result. The electrode composition of the first embodiment further satisfies the condition "(4) the weight average molecular weight (Mw) of the additive is 50,000 or less," which will be described later.

[0027] The HSP distance is determined from the Hansen solubility parameters (HSP values) of the two substances for which the HSP distance is determined. The HSP value is an index that takes into account the polarity of physical properties by dividing the Hildebrand solubility parameter (SP value) into three components: the dispersion force term δD, the polarity term δP, and the hydrogen bond term δH. 2 =δD 2 +δP 2 +δH 2 " There is a relationship between The HSP distance between two substances is expressed by the following formula, where δD, δP, and δH of the two substances are (δD1, δP1, δH1) and (δD2, δP2, δH2), respectively. HSP distance=SQRT(4×(δD1-δD2) 2 +(δP1-δP2) 2 +(δH1-δH2) 2 ) The HSP distance refers to the distance between two points when the HSP value is considered as a coordinate in three-dimensional space, and the smaller the HSP distance (the closer the HSP values ​​are), the more easily the two substances will dissolve.

[0028] The HSP value of a substance can be calculated by inputting its structural formula into HSPiP (Hansen Solubility Parameters in Practice: Hansen Solubility Parameter Software). Also, values ​​from the HSPiP database or literature values ​​may be used.

[0029] In addition to these methods, the HSP value may be determined experimentally. The target component is dispersed in a solvent with a known HSP value, and the dispersibility of that component in that specific solvent is evaluated. To evaluate dispersibility, the component for which HSP is to be determined is dispersed in the solvent, the absorption spectrum is measured, and the absorbance values ​​are recorded at 10-second intervals for 20 minutes (measurement wavelength: 632 nm). The dispersion index DISP is calculated by dividing the absorbance after 20 minutes by the absorbance at the start of measurement. The obtained dispersion index is used to evaluate the dispersibility in each solvent based on the following evaluation criteria. 1: DISP=0.30 or more 2: DISP = 0.20 or more and less than 0.30 3: DISP = 0.15 or more, less than 0.20 4: DISP = 0.10 or more and less than 0.15 5: DISP=less than 0.10 By inputting the evaluation results of dispersibility in each solvent into HSPiP, the HSP value of the target component can be calculated.

[0030] The solvent used in the method for determining the HSP value described above can be any of toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, methyl ethyl ketone (MEK), etc.

[0031] The HSP values ​​are determined for the active material and additives that constitute the electrode composition, and the HSP distance between the additive and the active material is determined from the HSP values ​​(more precisely, δD, δP, and δH of the active material and additive, respectively). The electrode composition of the present invention has an HSP distance (Ra_Act) between the additive and the active material of 12.0 MPa. 0.5 The details are as follows. In addition, the HSP distance between the additive and the active material is 4.0 MPa. 0.5 It is preferable that this is equal to or greater than this. The HSP distance between the additive and the active material is 4.0 MPa 0.5 If the HSP distance is less than 1 / 2 mm (if the HSP distance between the additive and the active material is close), the additive and the active material are highly compatible, so the surface of the active material may be corroded by the additive, making the electrode layer brittle when used as an electrode layer.

[0032] Although the electrolyte is not a component of the electrode composition, the electrode composition contains the electrolyte and is used as a secondary battery electrode layer, and the HSP distance between the additive and the electrolyte is determined in relation to the electrolyte contained in the electrode composition. The HSP values ​​are determined for the additive and the electrolyte, and the HSP distance between the additive and the electrolyte is determined from the HSP values ​​(more precisely, δD, δP, and δH of the additive and the electrolyte, respectively). The electrode composition of the present invention is a mixture of an additive and an electrolyte. HSP distance (Ra_Elec) is 14.0MPa 0.5 The details are as follows. In addition, the HSP distance between the additive and the electrolyte is 12.0 MPa. 0.5 It is preferable that: The lower limit of the HSP distance between the additive and the electrolyte is not particularly limited, but is, for example, 1.0 MPa. 0.5 It is preferable that this is equal to or greater than this.

[0033] The additive is not particularly limited as long as it is a compound that can satisfy the requirements (2) and (3) regarding the HSP distance, but specific examples include the following compounds. (A1) Alkyl alcohol alkylene oxide adduct (A2) Alkylene oxide adduct of alkylene glycol (A3) Glycol ethers (A4) Alkylene oxide adducts of bisphenols (A5) Ester compounds (A6) Amine compounds (A7) Alcohol

[0034] (A1) Alkyl alcohol alkylene oxide adduct The alkylene oxide preferably contains ethylene oxide. Alternatively, the alkylene oxide may contain alkylene oxides other than ethylene oxide. Examples of alkylene oxides other than ethylene oxide include propylene oxide and butylene oxide. In the present specification, alkylene oxide may be abbreviated as AO, ethylene oxide as EO, propylene oxide as PO, and butylene oxide as BO.

[0035] The alkylene oxide may be a combination of ethylene oxide and propylene oxide, a combination of ethylene oxide and butylene oxide, or a combination of ethylene oxide, propylene oxide and butylene oxide. When the alkylene oxide is composed of a plurality of types of alkylene oxides, the addition may be random addition or block addition.

[0036] The molar ratio of ethylene oxide in the alkylene oxide is preferably 85% or more based on the total number of moles of alkylene oxide. The alkylene oxide may be ethylene oxide alone, that is, the molar ratio of ethylene oxide in the alkylene oxide may be 100% based on the total number of moles of alkylene oxide. The molar ratio of ethylene oxide in the alkylene oxide may be 85 to 100%, 87 to 100%, 92 to 100%, 85 to 87%, 85 to 92%, or 87 to 92%.

[0037] The average number of moles of alkylene oxide added in the alkylene oxide adduct of alkyl alcohol is preferably 2 to 40. The average number of moles of alkylene oxide added may be 3-20 or 4-10. When there are multiple types of alkylene oxides, the number of moles of alkylene oxide added is the total number of moles of the multiple types of alkylene oxides added.

[0038] The alkyl alcohol constituting the alkylene oxide adduct of alkyl alcohol is preferably a saturated alkyl alcohol from the viewpoint of suppressing deterioration of battery performance due to side reactions that may occur during charging and discharging. The alkyl group of the alkyl alcohol may be straight-chain or branched-chain.

[0039] The number of carbon atoms in the alkyl group of the alkyl alcohol is not particularly limited, but is preferably 1 to 20. Examples of alkyl alcohols having 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 isotridecanol.

[0040] Specific examples of alkylene oxide adducts of alkyl alcohols include heptaethylene glycol monoisodecyl ether, tetraethylene glycol monopentadecyl ether, nonaethylene glycol monododecyl ether, and nonaethylene glycol monomethyl ether.

[0041] (A2) Alkylene oxide adduct of alkylene glycol The alkylene oxides that can be used are the same as those in (A1), and the addition forms and combinations of the alkylene oxides can also be the same as those in (A1). The molar ratio of ethylene oxide in the alkylene oxide is preferably 85% or more based on the total number of moles of alkylene oxide. The alkylene oxide may be ethylene oxide alone, that is, the molar ratio of ethylene oxide in the alkylene oxide may be 100% based on the total number of moles of alkylene oxide. The alkylene glycol is preferably ethylene glycol, and more preferably an ethylene oxide adduct of ethylene glycol (polyethylene glycol).

[0042] The average number of moles of alkylene oxide added in the alkylene oxide adduct of alkylene glycol is preferably 2 to 40. The average number of moles of alkylene oxide added may be 3-20 or 4-10. Specific examples of alkylene oxide adducts of alkylene glycol include tetraethylene glycol (number of moles of ethylene oxide added: 4), octaethylene glycol (number of moles of ethylene oxide added: 8), and heptapropylene glycol (number of moles of propylene oxide added: 7).

[0043] (A3) Glycol ethers The alkylene glycol unit in the glycol ether is preferably ethylene glycol or propylene glycol, more preferably ethylene glycol. The number of repeating alkylene glycol units is preferably 3 to 20, and may be 4 to 15. Specific examples of glycol ethers include triethylene glycol dimethyl ether, hexaethylene glycol tribenzyl phenyl ether, and tetradecaethylene glycol tribenzyl phenyl ether.

[0044] (A4) Alkylene oxide adducts of bisphenols This is a compound obtained by adding an alkylene oxide to a bisphenol. The alkylene oxide may be the same as in (A1), and the addition method and combination of the alkylene oxide may also be the same as in (A1). For example, EO adducts of bisphenol A, PO adducts of bisphenol A, and BO adducts of bisphenol A can be mentioned. The average number of moles of alkylene oxide added may be 1-20, or may be 1-5. Specific examples of alkylene oxide adducts of bisphenols include EO 2 mole adducts of bisphenol A.

[0045] (A5) Ester compounds These include carboxylic acid esters and phosphoric acid esters, and examples thereof include monoesters, diesters, triesters, and the like. Specific examples of the ester compound include methyl n-octanoate, methyl tetradecanoate, glycerin stearate, and phosphate triester (such as tris(2-chloro-1-methylethyl)phosphate).

[0046] (A6) Amine compounds Examples of the monoamine include saturated cyclic monoamines (for example, alicyclic amines (monoamines containing a saturated cyclic hydrocarbon group) {for example, cyclobutylamine, cyclopentylamine, cyclohexylamine, cycloheptylamine, dicyclohexylamine, N-methylcyclohexylamine, trimethylcyclohexylamine, aminomethylcyclohexane, 1-cyclohexylethylamine, etc.}, saturated heterocyclic monoamines {for example, morpholine, piperidine, etc.}, etc.), unsaturated cyclic monoamines (monoamines containing an unsaturated cyclic hydrocarbon group) (for example, aromatic amines {for example, aniline, anisidine, toluidine, trimethylaniline, etc.}, unsaturated heterocyclic monoamines {for example, pyrrole, azepine, azonine, etc.}, etc.). Of these, cyclohexylamine is preferred.

[0047] (A7) Alcohol Examples of the alcohol include aliphatic alcohols, aromatic alcohols, and aromatic aliphatic alcohols. Fatty alcohols are preferred, and the number of carbon atoms in the aliphatic group moiety is not particularly limited, but may be 1 to 20 or 10 to 20. A specific example of the alcohol is hexadecanol.

[0048] The content of the additive is preferably 0.001 to 2% by weight based on the weight of the electrode composition. When the content of the additive is in this range, the effect of including the additive can be more suitably exhibited.

[0049] (electrolyte) As the electrolyte, an electrolyte for a secondary battery can be used, and an electrolyte containing a non-aqueous solvent that can be used in a lithium ion battery can be preferably used. The electrolyte has an HSP distance (Ra_Elec) of 14.0 MPa with the additives contained in the electrode composition. 0.5 Use the following:

[0050] The solvent contained in the electrolyte is 、 Non-aqueous solvents used in known electrolytic solutions can be used, such as lactone compounds, cyclic or chain carbonate esters, chain carboxylic acid esters, cyclic or chain ethers, phosphate esters, nitrile compounds, amide compounds, sulfones, sulfolane, and mixtures thereof.

[0051] Examples of lactone compounds include lactone compounds with five-membered rings (such as γ-butyrolactone and γ-valerolactone) and six-membered rings (such as δ-valerolactone).

[0052] Examples of cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), and butylene carbonate (BC). Examples of the chain carbonate ester include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl-n-propyl carbonate, ethyl-n-propyl carbonate, and di-n-propyl carbonate.

[0053] Examples of the chain carboxylic acid ester include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate.

[0054] Examples of cyclic ethers include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, and 1,4-dioxane. Examples of chain ethers include dimethoxymethane and 1,2-dimethoxyethane.

[0055] 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-dioxaphospholan-2-one, 2-trifluoroethoxy-1,3,2-dioxaphospholan-2-one, and 2-methoxyethoxy-1,3,2-dioxaphospholan-2-one.

[0056] Examples of nitrile compounds include acetonitrile, etc. Examples of amide compounds include DMF, etc. Examples of sulfones include dimethyl sulfone and diethyl sulfone, etc.

[0057] These solvents may be used alone or in combination of two or more. The mixed solvent is preferably a mixed solvent of ethylene carbonate and diethyl carbonate, a mixed solvent of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate, or a mixed solvent of ethylene carbonate and propylene carbonate.

[0058] The electrolyte contained in the electrolytic solution can be any electrolyte used in known electrolytic solutions, including, for example, lithium salts of inorganic anions such as LiPF, LiBF, LiSbF, LiAsF, LiClO, and LiN(FSO), and lithium salts of organic anions such as LiN(CFSO), LiN(CFS0), and LiC(CFSO). Of these, LiPF (lithium hexafluorophosphate), LiFSI (lithium bis(fluorosulfonyl)imide), and the like are preferably used.

[0059] The concentration of the electrolyte in the electrolytic 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.

[0060] The HSP value of an electrolyte solution depends almost entirely on the type of solvent, so the HSP value can be calculated based on the type of solvent without considering the influence of the electrolyte. When a mixed solvent is used as the solvent, the average of the HSP values ​​of each solvent (δD, δP, and δH) is used as each term of the HSP value of the mixed solvent based on the volume ratio of each solvent.

[0061] (binder resin) The electrode composition of the first type does not contain a binder resin, and the electrode composition of the second type contains a binder resin, which will be described below. Substances that can be used as additives include substances known as binder resins, but in this specification, binder resins are substances that are distinguished from additives.

[0062] 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. When the electrode composition contains these substances, it is considered to contain a binder resin. Furthermore, these substances are not included in the additives of the present invention even if the relationship between the HSP distance from the active material and the HSP distance from the electrolyte satisfies the requirements of the present invention.

[0063] Furthermore, many binder resins have a weight-average molecular weight (Mw) of more than 50,000. From this perspective, the first type of electrode composition, which does not contain a binder resin, is specified to satisfy the requirement "(4) The weight-average molecular weight (Mw) of the additive is 50,000 or less." The weight average molecular weight of the additive may be a molecular weight determined based on the structural formula of the additive, and when determined by measurement, it can be measured by gel permeation chromatography under the following conditions, for example. Apparatus: "Waters Alliance 2695" [Waters] Column: "Guardcolumn Super HL" (1 column), "TSKgel SuperH2000, TSKgel SuperH3000, TSKgel SuperH4000 (all manufactured by Tosoh Corporation) connected together (1 column each)" Sample solution: 0.25% by weight tetrahydrofuran solution Solution injection volume: 10μl Flow rate: 0.6ml / min Measurement temperature: 40℃ Detector: Refractive index detector Reference material: Standard polyethylene glycol

[0064] On the other hand, the electrode composition of the second type is specified to contain a binder resin, and may contain a substance having a weight-average molecular weight of more than 50,000. When the electrode composition contains a binder resin, the content of the binder resin is preferably more than 0 wt % and not more than 6.0 wt % based on the weight of the electrode composition.

[0065] The electrode composition of the present invention may contain a conductive additive, such as metals (aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.), carbon (graphite (flaky graphite (UP)), carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), carbon nanofibers (CNF), etc.), and mixtures thereof. The conductive aid is preferably acetylene black. Carbon-based materials are used both as negative electrode active materials and as conductive additives, but in this application, those with a volume average particle diameter of 10.0 μm or more are considered to be negative electrode active materials, and those with a volume average particle diameter of less than 10.0 μm are considered to be conductive additives.

[0066] The electrode composition of the present invention has an HSP distance between the active material and the additive of 12.0 MPa. 0.5 Since the HSP distance between the additive and the electrolyte is 14.0MPa, the active material and the additive are well-matched, and the surface of the active material is treated with the additive. 0.5 The following conditions are met, which stipulate that the additive and the electrolyte have a good compatibility with each other. Therefore, the electrolyte can easily penetrate into the electrode composition. Therefore, the electrode composition of the present invention is an electrode composition that can be used to produce an electrode with excellent electrolyte permeability. Furthermore, the electrode composition of the present invention has excellent electrolyte permeability even when the electrode density is increased, and therefore is an electrode composition that can be used to produce high energy density electrodes without reducing production capacity.

[0067] Furthermore, the HSP distance between the active material and the additive is 4.0 MPa. 0.5 If the above is the case, an electrode composition can be obtained that can produce an electrode having good properties in terms of electrode brittleness.

[0068] [Secondary battery electrodes and secondary batteries] The secondary battery electrode of the present invention is an electrode for a secondary battery obtained by compression molding the electrode composition of the present invention. As the electrode composition of the present invention, either the electrode composition of the first type or the electrode composition of the second type may be used. The method for compression molding the electrode composition is not particularly limited, but methods such as roll pressing and pressing with a press can be used. The electrode density of the secondary battery electrode obtained by compression molding the electrode composition is 1.0 to 2.0 g / cm. 3 It is preferable that: The electrode density defined here means the density in a state where the electrode composition is not permeated with an electrolyte. Furthermore, a secondary battery comprising the above-described secondary battery electrode of the present invention is also the secondary battery of the present invention. In this secondary battery of the present invention, the configuration other than that of the secondary battery electrode of the present invention is not particularly limited.

[0069] [Secondary battery] The secondary battery of the present invention includes the secondary battery provided with the secondary battery electrode of the present invention described above, as well as the following first and second types of secondary batteries. The first type of secondary battery corresponds to the first type of electrode composition, and the second type of secondary battery corresponds to the second type of electrode composition.

[0070] The secondary battery of the first embodiment is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and is a secondary battery that satisfies all of the following (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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 Below is; (4) The weight average molecular weight (Mw) of the additive is 50,000 or less.

[0071] The secondary battery of the second embodiment is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and is a secondary battery that satisfies all of the following (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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 The following is the result.

[0072] The above-mentioned requirements (2) to (4) in the secondary batteries of the first and second embodiments are the same as the requirements (2) to (4) in the electrode composition of the present invention. The secondary batteries of the first and second embodiments include a secondary battery electrode layer. In (1), it is specified that the secondary battery electrode layer contains an electrolyte solution.

[0073] The secondary battery electrode layer is a layer containing an electrolyte solution in the electrode composition of the first and second embodiments. The secondary battery electrode layer can contain a sufficient amount of electrolyte solution in a short time due to the good electrolyte solution permeability of the electrode composition of the first and second embodiments. Because the secondary battery electrode layer can contain a sufficient amount of electrolyte solution in a short time, the secondary batteries of the first and second embodiments can be produced in a short time and can extract a capacity close to the theoretical value.

[0074] Other components of the secondary battery than the secondary battery electrode layer include a current collector layer and a separator layer. As the current collector layer and separator layer, a current collector and separator that can be used in a typical lithium ion secondary battery can be used.

[0075] The secondary battery of the present invention can be used as a secondary battery for use in mobile phones, personal computers, hybrid vehicles, electric vehicles, stationary power sources, and the like.

[0076] [Electrolyte penetration method] The electrolyte solution penetration method of the present invention includes the following first and second embodiments of the electrolyte solution penetration method. The first form of the electrolyte solution penetration method corresponds to the method of permeating the first form of the electrode composition with an electrolyte solution, and the second form of the electrolyte solution penetration method corresponds to the method of permeating the second form of the electrode composition with an electrolyte solution.

[0077] The first embodiment of the electrolyte solution penetration method is a method of permeating an electrode composition with an electrolyte solution, and is an electrolyte solution penetration method that satisfies all of the following (1) to (4). (1) The electrode composition 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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 Below is; (4) The weight average molecular weight (Mw) of the additive is 50,000 or less.

[0078] The second embodiment of the electrolyte solution penetration method is a method of permeating an electrode composition with an electrolyte solution, and is an electrolyte solution penetration method that satisfies all of the following (1) to (3). (1) The electrode composition 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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 The following is the result.

[0079] In any of the electrolyte solution penetration methods, the means for impregnating the electrode composition with the electrolyte solution is not particularly limited, and any one of a spray coater, a dispenser, a die coater, and a roll coater may be used. Alternatively, after assembling components constituting a battery, such as an electrode composition, a current collector, and a separator, and sealing them with a sealing member, an electrolytic solution may be injected into the electrode composition through an injection port provided in the sealing member, thereby allowing the electrolytic solution to permeate the electrode composition.

[0080] In the electrolyte solution penetration method of the present invention, the electrolyte solution permeability into the electrode composition is good, so the work of permeating the electrolyte solution into the electrode composition can be completed in a short time, and the workability when obtaining a secondary battery electrode layer is good. The working time (permeation time) for permeating the electrode composition with the electrolyte solution varies depending on the type of electrolyte solution, the size of the secondary battery, etc., but can be, for example, 300 minutes or less.

[0081] [Secondary battery manufacturing method] The method for manufacturing a secondary battery of the present invention includes the following first embodiment of a method for manufacturing a secondary battery and the second embodiment of a method for manufacturing a secondary battery. The method for producing a secondary battery of the first aspect corresponds to the method for producing a secondary battery by permeating an electrolyte solution into the electrode composition of the first aspect, and the method for producing a secondary battery of the second aspect corresponds to the method for producing a secondary battery by permeating an electrolyte solution into the electrode composition of the first aspect. Secondary battery manufacturing method corresponds to a method for producing a secondary battery by impregnating an electrolyte solution into the electrode composition of the second embodiment.

[0082] The first embodiment of the method for manufacturing a secondary battery includes a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, and the method for manufacturing a secondary battery satisfies all of the following (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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 Below is; (4) The weight average molecular weight (Mw) of the additive is 50,000 or less.

[0083] The second embodiment of the method for manufacturing a secondary battery includes a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, and the method for manufacturing a secondary battery satisfies all of the following (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 Below is; (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 The following is the result.

[0084] In any of the methods for manufacturing a secondary battery, the means for permeating the electrolyte solution into the battery unit including the electrode composition layer is not particularly limited, and any one of a spray coater, a dispenser, a die coater, and a roll coater may be used. When the electrolyte solution is impregnated into the battery unit, the electrolyte solution may be impregnated into the electrode composition to form a secondary battery electrode layer, and then the current collector layer and separator layer may be combined to form a battery unit having the secondary battery electrode layer. Alternatively, the current collector layer, electrode composition layer, and separator layer may be combined, and then the electrolyte solution may be impregnated into the electrode composition layer to form a secondary battery electrode layer, and then the battery unit having the secondary battery electrode layer may be formed.

[0085] In the method for manufacturing a secondary battery of the present invention, since the electrolyte solution has good permeability into the electrode composition, the work of permeating the electrolyte solution into the electrode composition can be completed in a short time, and the workability when obtaining the secondary battery electrode layer is good. The working time (permeation time) for permeating the electrode composition with the electrolyte solution varies depending on the type of electrolyte solution, the size of the secondary battery, etc., but can be, for example, 300 minutes or less.

[0086] The present specification discloses the following:

[0087] The present disclosure (1) provides an electrode composition for a secondary battery electrode layer, which contains an electrolytic solution and satisfies all of the following (1) to (4): (1) it contains an active material and an additive, but does not contain a binder resin; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0088] The present disclosure (2) provides an electrode composition for a secondary battery electrode layer, which contains an electrolytic solution and satisfies all of the following (1) to (3): (1) the electrode composition 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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result.

[0089] In the present disclosure (3), the HSP distance (Ra_Act) between the additive and the active material is 4.0 MPa. 0.5 The electrode composition according to the present disclosure (1) or (2) is as described above.

[0090] In the present disclosure (4), the HSP distance (Ra_Elec) between the additive and the electrolyte is 12.0 MPa. 0.5 The electrode composition according to any one of the following disclosures (1) to (3) is described below.

[0091] The present disclosure (5) is the electrode composition according to any one of the present disclosures (1) to (4), in which the additive is an alkylene oxide adduct of an alkyl alcohol or an alkylene oxide adduct of an alkylene glycol.

[0092] The present disclosure (6) is the electrode composition according to the present disclosure (5), wherein the alkyl alcohol is a saturated alkyl alcohol.

[0093] The present disclosure (7) is the electrode composition according to any one of the present disclosures (1) to (6), wherein the active material is at least one selected from the group consisting of a composite oxide containing at least one transition metal element, artificial graphite, and natural graphite.

[0094] The present disclosure (8) is the electrode composition according to any one of the present disclosures (1) to (7), wherein the solvent of the electrolytic solution is a mixed solvent of ethylene carbonate and diethyl carbonate, a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate, or a mixed solvent of ethylene carbonate and propylene carbonate.

[0095] The present disclosure (9) is an electrode for a secondary battery obtained by compression molding the electrode composition according to any one of the present disclosures (1) to (8).

[0096] The present disclosure (10) is a secondary battery including the electrode for a secondary battery according to the present disclosure (9).

[0097] The present disclosure (11) is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and satisfies all of the following (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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0098] The present disclosure (12) is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and satisfies all of the following (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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result.

[0099] The present disclosure (13) is a method for permeating an electrode composition with an electrolyte solution, which satisfies all of the following (1) to (4): (1) the electrode composition 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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0100] The present disclosure (14) is a method for permeating an electrode composition with an electrolyte solution, which satisfies all of the following (1) to (3): (1) the electrode composition 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 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result.

[0101] The present disclosure (15) is a method for producing a secondary battery, which includes a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, and which satisfies all of the following (1) to (4): (1) the electrode composition layer contains an active material and an additive, but does not contain a binder resin; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 (4) the weight average molecular weight (Mw) of the additive is 50,000 or less;

[0102] The present disclosure (16) is a method for producing a secondary battery, which includes a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, and which satisfies all of the following (1) to (3): (1) the electrode composition layer contains an active material, a binder resin, and an additive; and (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa or less; 0.5 The following is the result. [Example]

[0103] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples as long as they do not deviate from the gist of the present invention. Unless otherwise specified, parts mean parts by weight and % means % by weight.

[0104] (Preparation of Additives 1 to 21) The following additives 1 to 21 were prepared. (Additive 1) Methyl n-octanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 1. (Additive 2) Methyl tetradecanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 2. (Additive 3) Glycerin and stearic acid (molar ratio: 1 / 1) were added to xylene to initiate the esterification reaction (xylene content was 50 wt% of the total). Polymerization was carried out under reflux, and the water produced in the esterification reaction was removed together with the xylene. The amount of xylene removed was then added, and the reaction was continued until no more water was produced. After the reaction, the xylene was removed using a vacuum dryer, yielding solid glycerin stearate, which was designated as Additive 3.

[0105] (Additive 4) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to isodecanol was obtained as Additive 4. The average number of moles of EO added is 7.0, and the compound name is heptaethylene glycol monoisodecyl ether. (Additive 5) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to pentadecyl alcohol was obtained as Additive 5. The average number of moles of EO added is 4.0, and the compound name is tetraethylene glycol monopentadecyl ether. (Additive 6) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to dodecanol was obtained as Additive 6. The average number of moles of EO added is 9.0, and the compound name is nonaethylene glycol monododecyl ether.

[0106] (Additive 7) Tetraethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 7. (Additive 8) Octaethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 8. (Additive 9) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to methanol was obtained as Additive 9. The average number of moles of EO added is 9.0, and the compound name is nonaethylene glycol monomethyl ether.

[0107] (Additive 10) Triethylene glycol dimethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 10. (Additive 11) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to tribenzylphenol was obtained as Additive 11. The average number of moles of EO added is 6.0, and the compound name is hexaethylene glycol tribenzyl phenyl ether. (Additive 12) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to tribenzylphenol was obtained as Additive 12. The average number of moles of EO added is 14.0, and the compound name is tetradecaethylene glycol tribenzyl phenyl ether.

[0108] (Additive 13) Cyclohexylamine (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 13. (Additive 14) An alkylene oxide adduct of alkyl alcohol produced by adding ethylene oxide (EO) to bisphenol A was obtained as Additive 14. The average number of moles of EO added is 2.0, and the compound is called a bisphenol A adduct of 2 moles of EO. (Additive 15) Tris(2-chloro-1-methylethyl) phosphate (reagent: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as additive 15.

[0109] (Additive 16) An alkylene oxide adduct of alkyl alcohol produced by adding propylene oxide (PO) to propylene glycol was obtained as Additive 16. The average number of moles of PO added is 6.0, and the compound name is heptapropylene glycol. (Additive 17) Hexadecanol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 17. (Additive 18) Triethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 18.

[0110] (Additive 19) Ethylene glycol monomethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 19. (Additive 20) Trimethylolpropane (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 20. (Additive 21) N-(hydroxymethyl)methacrylamide (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 21.

[0111] (Preparation of electrolytes 1 to 4) All of the substances prepared below are reagents (manufactured by Tokyo Chemical Industry Co., Ltd.). (electrolyte 1) Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of EC:DEC=1:1, and lithium hexafluorophosphate (LIPF6) was dissolved therein to give a 1 M electrolyte solution 1. (electrolyte 2) Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC = 2:4:4, and lithium hexafluorophosphate (LIPF6) was dissolved in the mixture to a concentration of 1 M to prepare electrolyte solution 2. (Electrolyte 3) Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC = 3:5:2, and lithium hexafluorophosphate (LIPF6) was dissolved in the mixture to a concentration of 1 M to prepare electrolyte solution 3. (electrolyte 4) Ethylene carbonate (EC) and propylene carbonate (PC) were mixed at a volume ratio of EC:PC=1:1, and lithium hexafluorophosphate (LIPF6) was dissolved therein to give a 1 M electrolyte solution 4.

[0112] (Preparation of negative electrode active material) The following negative electrode active materials were prepared. Graphite 1: Artificial graphite (FSN-1, manufactured by Shanshan, China, volume average particle size (D50): 15.3 μm) Graphite 2: spherical graphite (CGR 12R, manufactured by Nippon Graphite Industries Co., Ltd., volume average particle diameter: 10.6 μm)

[0113] (Calculation of HSP value of negative electrode active material: graphite 1) The dispersibility of graphite 1 in various solvents was evaluated by the following method. 20 mL of a solvent with a known solubility parameter and 0.04 g of graphite 1 were placed in a Maruemu No. 7 screw tube, and a stirring bar was added and the mixture was stirred at 400 rpm for 30 minutes to prepare a suspension. The suspension was then left to stand in a thermostatic bath at 25°C for 12 hours to prepare a dispersion for measurement. The solvents with known solubility parameters were toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, and methyl ethyl ketone (MEK). The solubility parameters of these solvents were referenced from the HSPiP database. In addition, 20 mL of each solvent was placed in a No. 7 screw tube manufactured by Maruemu Co., Ltd., and similarly left to stand in a thermostatic bath at 25°C for 12 hours to serve as a reference solvent.

[0114] A baseline measurement was performed using a UV-Visible-NIR spectrophotometer (UV-3600i Plus, Shimadzu Corporation) with the reference solvent. The measurement dispersion corresponding to the reference solvent was then stirred in a screw tube for at least one minute. While stirring, the dispersion was thoroughly dispersed. 1000 μL of the dispersion was transferred into a quartz cell containing a stir bar four times with a micropipette. This was used as the measurement cell. The measurement cell was placed in a holder with a stirrer and stirred for 30 seconds. The stirring was stopped and the absorption spectrum measurement was initiated. The absorbance values ​​were recorded at 10-second intervals for 20 minutes (measurement wavelength: 632 nm). The dispersion index (DISP) was calculated as "absorbance after 20 minutes (A20) / absorbance at the start of measurement (A0)." The dispersion index was used to evaluate the dispersibility in each solvent based on the following criteria.

[0115] (Evaluation criteria) 1: DISP=0.30 or more 2: DISP = 0.20 or more and less than 0.30 3: DISP = 0.15 or more, less than 0.20 4: DISP = 0.10 or more and less than 0.15 5: DISP=less than 0.10 The evaluation results of the dispersibility of graphite 1 in a solvent were input into HSPiP to calculate the HSP value of graphite 1. The evaluation results of dispersibility used to calculate the HSP value of graphite 1 are shown in Table 1.

[0116] [Table 1]

[0117] (Calculation of HSP value of negative electrode active material: graphite 2) The HSP value of graphite 2 was also calculated in the same manner as for graphite 1. Of the solvents with known solubility parameters used to calculate the HSP value of graphite 1, hexane was not used, and other solvents were used instead. Other procedures were the same as for graphite 1. Table 2 shows the evaluation results of dispersibility used to calculate the HSP value of graphite 2.

[0118] [Table 2]

[0119] (Preparation of positive electrode active material) The following positive electrode active materials were prepared. NCM: NCM811 RL-08-D3 (Umicore) The composition is LiNi 0.8 Co 0.1 Mn 0.1 O2

[0120] (Calculation of HSP value of positive electrode active material: NCM) The HSP value of NCM, which is the positive electrode active material, was calculated in the same manner as for graphite 1. Table 3 shows the evaluation results of dispersibility used to calculate the HSP value of NCM.

[0121] [Table 3]

[0122] The solubility parameters of graphite 1, graphite 2, and NCM calculated based on the results shown in Tables 1, 2, and 3 above are shown in Table 4.

[0123] [Table 4]

[0124] (Examples 1 to 55, Comparative Examples 1 to 39, graphite 1 used) (Preparation of negative electrode with additive) 2.0 parts by weight of AB (acetylene black: "Denka Black Li100", manufactured by Denka Co., Ltd., average particle size of primary particles: 35 nm) as a conductive additive, 3.0 parts by weight of CMC (carboxymethyl cellulose) as a binder resin, and 40.0 parts by weight of ion-exchanged water were stirred at 2000 rpm for 5 minutes using a planetary stirring type mixer / kneader {Awatori Rentaro [manufactured by Thinky Corporation]}.

[0125] Next, 3.0 parts by weight of SBR (styrene butadiene rubber) as a binder resin was added, and the mixture was stirred for 5 minutes at 2000 rpm using a mixer. To the resulting dispersion, 91.0 parts by weight of graphite 1 as a negative electrode active material, 1.0 part by weight of additive, and 60.0 parts by weight of ion-exchanged water were added, and the mixture was stirred for 5 minutes at 2000 rpm using a mixer to prepare a slurry for the negative electrode active material layer.

[0126] The resulting negative electrode active material layer slurry was applied to one side of a current collector (copper foil) using an applicator with a clearance set to 150 μm in the atmosphere. After pre-drying overnight in a draft chamber, the electrode sheet was further dried under reduced pressure (1.3 kPa) at 100°C for 2 hours to obtain an electrode sheet. Sixteen 16 mm diameter electrodes were punched out near the center of the electrode sheet. This procedure was repeated multiple times, and three of the resulting electrodes were used as electrodes (negative electrodes) for simple electrode brittleness testing. The remaining electrodes were pressed twice in a press at 1.5 MPa for 3 seconds to prepare evaluation electrodes (negative electrodes). Negative electrodes were prepared for additives 1 to 21.

[0127] (Fabrication of negative electrode without additives) An electrode (negative electrode) for simple electrode brittleness testing and an electrode (negative electrode) for evaluation were prepared in the same manner as the negative electrode with additive, except that graphite 1 was used at 92.0 parts by weight and no additive was added.

[0128] <Calculation of electrode density> The current collector and the evaluation electrode were pressed twice for 3 seconds at 1.5 MPa using a press machine, and the weight and thickness were measured and calculated using the following formula. Electrode density (g / cm 3 ) = (evaluation electrode weight (g) - current collector weight (μg) × 10 -3 ) / (0.8 2 × 3.14 × ((electrode thickness for evaluation (μm) - current collector thickness (μm)) × 10 -4 ))

[0129] <Simple electrode brittleness test> Three electrodes for the simple electrode brittleness test were dropped from a height of 30 cm onto a piece of white paper, and the results were evaluated according to the following criteria. 〇: 0 pieces of electrode pieces stuck to the white paper ×: One or more electrode pieces stuck to the white paper

[0130] <Electrolyte penetration test> Among the electrodes for evaluation, the electrode density (g / cm 3 ) maximum and minimum difference is 0.03 (g / cm 3 ) or less, and the arithmetic average of these three electrodes was calculated as the electrode density (g / cm) of the evaluation electrode. 3 ) was recorded. A stainless steel M3 flat washer (manufactured by Esco) was placed at the center of each electrode, and 20 μL of electrolyte was dropped into the hole in the washer. The time until the droplet inside the washer completely disappeared from the electrode surface was recorded in 1-second increments, and the arithmetic mean value was taken as the electrolyte penetration time (penetration rate: minutes). For each of the electrolytes 1 to 4, an electrolyte penetration test was carried out.

[0131] <Capacity retention rate after severe testing> Preparation of negative electrode half-cell for capacity retention stress test Among the electrodes for evaluation, the electrode density (g / cm 3 ) maximum and minimum difference is 0.03 (g / cm 3 ) or less, and the arithmetic average of these three electrodes was calculated as the electrode density (g / cm) of the evaluation electrode. 3 ) was recorded. The negative electrode, a separator [product name "#3501" manufactured by Celgard Inc.], and a lithium foil were stacked in this order from the negative electrode side, an electrolyte solution was injected, and then the resultant was vacuum laminated to prevent oxygen from entering, thereby preparing a negative electrode half cell for a severe capacity retention test.

[0132] Negative electrode half-cell charge / discharge test The capacity retention rate of the negative electrode half-cell for the severe test was evaluated at 25°C using a charge / discharge measuring device "HJ-SD8" (manufactured by Hokuto Denko Corporation) according to the following method. The battery was charged to 0V at a current of 0.05C using the constant current charging method (also known as CC mode), and after a 10-minute rest, it was discharged to 1.5V at a current of 0.05C. The discharged capacity at this time was defined as [1 cycle discharge capacity (mAh)]. The battery was charged and discharged again under the same conditions, and the discharged capacity at this time was defined as [2-cycle discharge capacity (mAh)]. Next, the battery was charged to 0V at a current of 0.1C, and after a 10-minute rest, it was discharged to 1.5V at a current of 0.1C. The discharged capacity at this time was defined as [3-cycle discharge capacity (mAh)]. Furthermore, the battery was charged to 0V at a current of 0.5C, and after a 10-minute rest, it was discharged to 1.5V at a current of 0.1C. The discharged capacity at this time was defined as [4-cycle discharge capacity (mAh)]. Finally, the battery was charged to 0 V at a current of 1.0 C, and after a 10-minute rest, it was discharged to 1.5 V at a current of 0.1 C. The discharged capacity at this time was defined as [5-cycle discharge capacity (mAh)]. The capacity retention rate after the severe test for each of the three electrodes was calculated using the following formula, and the arithmetic mean was taken as the capacity retention rate (%) after the severe test for the evaluation electrode. Capacity retention rate after severe test (%) = [5-cycle discharge capacity (mAh)] / [2-cycle discharge capacity (mAh)] An electrolyte penetration test was carried out for each of Examples 1 to 17 in which additives 1 to 17 were used, Comparative Examples 1 to 4 in which no additive was used, and Comparative Examples 5 to 8 in which additives 18 to 21 were used.

[0133] The evaluation results using Graphite 1 are summarized in Tables 5 to 12. Tables 5 and 6 show examples and comparative examples using electrolyte solution 1, Tables 7 and 8 show examples and comparative examples using electrolyte solution 2, Tables 9 and 10 show examples and comparative examples using electrolyte solution 3, and Tables 11 and 12 show examples and comparative examples using electrolyte solution 4. The units of HSP distance in each table below are [MPa 0.5 ].

[0134] [Table 5]

[0135] [Table 6]

[0136] [Table 7]

[0137] [Table 8]

[0138] [Table 9]

[0139] [Table 10]

[0140] [Table 11]

[0141] [Table 12]

[0142] (Examples 56 to 106, Comparative Examples 40 to 82, Graphite 2 used) Negative electrodes with and without additives were fabricated using graphite 2 instead of graphite 1, and the electrode density was calculated, and a simple electrode brittleness test and electrolyte penetration test were performed. No test for capacity retention after severe testing was performed.

[0143] The evaluation results using Graphite 2 are summarized in Tables 13 to 20. Tables 13 and 14 show examples and comparative examples using electrolyte solution 1, Tables 15 and 16 show examples and comparative examples using electrolyte solution 2, Tables 17 and 18 show examples and comparative examples using electrolyte solution 3, and Tables 19 and 20 show examples and comparative examples using electrolyte solution 4.

[0144] [Table 13]

[0145] [Table 14]

[0146] [Table 15]

[0147] [Table 16]

[0148] [Table 17]

[0149] [Table 18]

[0150] [Table 19]

[0151] [Table 20]

[0152] (Examples 107 to 149, Comparative Examples 83 to 133, NCM used) (Preparation of positive electrode with additive) 1.0 part by weight of additive and 100.0 parts by weight of N-methyl-2-pyrrolidone (NMP) were stirred at 2000 rpm for 5 minutes using a planetary stirring mixer (Thinky Mixer) Next, 3.0 parts by weight of polyvinylidene fluoride (Kishida Chemical) as a binder resin was added, and the mixture was stirred at 2000 rpm for 5 minutes using the Mixer.

[0153] Further, 89.0 parts by weight of NCM as a 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 were added, and the mixture was stirred at 2000 rpm for 4 minutes using an Awatori Mixer to prepare a slurry for a positive electrode active material layer.

[0154] The resulting positive electrode active material layer slurry was applied to one side of a current collector (aluminum foil, manufactured by Hosen Co., Ltd.) using an applicator with a clearance set to 150 μm in the atmosphere. After pre-drying overnight in a draft chamber, the electrode sheet was further dried under reduced pressure (1.3 kPa) at 100°C for 2 hours to obtain an electrode sheet. Sixteen 15 mm diameter electrodes were punched out from the center of the electrode sheet. This procedure was repeated multiple times, and three of the resulting electrodes were used as electrodes (positive electrodes) for simple electrode brittleness testing. The remaining electrodes were pressed twice in a press at 4.0 MPa for 3 seconds to prepare electrodes (positive electrodes) for evaluation. Each positive electrode was prepared using additives 1 to 21.

[0155] (Preparation of positive electrode without additives) An electrode (positive electrode) for simple electrode brittleness testing and an electrode (positive electrode) for evaluation were prepared in the same manner as the positive electrode with additive, except that the amount of NCM was 90.0 parts by weight and no additive was added.

[0156] For the electrode (positive electrode) for the simple electrode brittleness test and the evaluation electrode (positive electrode), the electrode density was calculated, and a simple electrode brittleness test and electrolyte penetration test were performed using the same procedures as for the negative electrode. No test for capacity retention after the severe test was performed. In calculating the electrode density, the calculation formula was corrected to reflect the difference in the diameter of the punched electrode sheet.

[0157] The evaluation results using NCM are summarized in Tables 21 to 28. Tables 21 and 22 show examples and comparative examples using electrolyte solution 1, Tables 23 and 24 show examples and comparative examples using electrolyte solution 2, Tables 25 and 26 show examples and comparative examples using electrolyte solution 3, and Tables 27 and 28 show examples and comparative examples using electrolyte solution 4.

[0158] [Table 21]

[0159] [Table 22]

[0160] [Table 23]

[0161] [Table 24]

[0162] [Table 25]

[0163] [Table 26]

[0164] [Table 27]

[0165] [Table 28]

[0166] From these results, for electrodes using the same active material and electrolyte, the penetration rate in each example in which the HSP distance between the active material and the additive and the HSP distance between the electrolyte and the additive were within the specified range was faster (shorter penetration time) than in the comparative example. Regarding electrode density, the electrode density was changed over a relatively wide range in the comparative examples (for example, the electrode density was changed over a range of 1.53 to 1.64 in comparative examples 1 to 4), but the permeation rate in each example was faster than the results of any of the comparative examples, which shows that regardless of the electrode density, excellent electrolyte permeability is achieved by satisfying the requirements of the present invention. In addition, in Examples 1 to 17, the battery performance was checked (severe test) for Additives 1 to 17, which were effective in improving permeability, and none of them had any adverse effect on the battery performance.

[0167] In addition, the HSP distance between the active material and the additive is 4.0 MPa. 0.5 In Examples where the compatibility between the additive and the active material was high (Examples 11, 12, etc.), the surface of the active material was corroded by the additive, and the electrode brittleness was evaluated as ×.

Claims

1. An electrode composition for a secondary battery electrode layer containing an electrolytic solution, wherein a solvent for the electrolytic solution is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof, and the electrode composition satisfies all of the following (1) to (4): (1) 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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ The following is true: (4) The weight average molecular weight (Mw) of the additive is 50,000 or less, the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

2. An electrode composition for a secondary battery electrode layer containing an electrolytic solution, wherein a solvent for the electrolytic solution is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof, and the electrode composition satisfies all of the following (1) to (3): (1) 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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ is as follows: the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

3. The HSP distance (Ra_Act) between the additive and the active material is 4.0 MPa ０．５ 3. The electrode composition according to claim 1 or 2, wherein the above-mentioned

4. The HSP distance (Ra_Elec) between the additive and the electrolyte is 12.0 MPa. ０．５ 3. The electrode composition according to claim 1, wherein:

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

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

7. 3. The electrode composition according to claim 1, wherein the active material is at least one selected from the group consisting of a composite oxide containing at least one transition metal element, artificial graphite, and natural graphite.

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

9. 3. An electrode for a secondary battery, obtained by compression molding the electrode composition according to claim 1 or 2.

10. A secondary battery comprising the electrode for a secondary battery according to claim 9.

11. A secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, A secondary battery that satisfies all of the following (1) to (4): (1) The secondary battery electrode layer contains an active material, an electrolyte solution, and an additive, but does not contain a binder resin, and the solvent of the electrolyte solution is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa ０．５ The following is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ The following is true: (4) The weight average molecular weight (Mw) of the additive is 50,000 or less, the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

12. A secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, A secondary battery that satisfies all of the following (1) to (3): (1) The secondary battery electrode layer contains an active material, an electrolyte, a binder resin, and an additive, and the solvent of the electrolyte is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa ０．５ The following is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ is as follows: the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

13. A method for permeating an electrode composition with an electrolyte solution, the method comprising the steps of: a solvent for the electrolyte solution being a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; An electrolyte penetration method that satisfies all of the following (1) to (4): (1) The electrode composition 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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ The following is true: (4) The weight average molecular weight (Mw) of the additive is 50,000 or less, the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

14. A method for permeating an electrode composition with an electrolyte solution, the method comprising the steps of: a solvent for the electrolyte solution being a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; An electrolyte penetration method that satisfies all of the following (1) to (3): (1) The electrode composition 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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ is as follows: the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

15. A method for producing a secondary battery, comprising a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, wherein a solvent for the electrolytic solution is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; A method for manufacturing a secondary battery that satisfies all of the following (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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ The following is true: (4) The weight average molecular weight (Mw) of the additive is 50,000 or less, the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

16. A method for producing a secondary battery, comprising a step of permeating an electrolytic solution into a battery unit including a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer in which the electrolytic solution is contained in the electrode composition layer, wherein a solvent for the electrolytic solution is a lactone compound, a cyclic carbonate ester, a chain carbonate ester, or a mixture thereof; A method for manufacturing a secondary battery that satisfies all of the following (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 is true: (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa. ０．５ is as follows: the active material is at least one selected from the group consisting of composite oxides containing at least one transition metal element, lithium-containing transition metal phosphates, transition metal oxides, transition metal sulfides, conductive polymers, graphite, non-graphitizable carbon, amorphous carbon, baked resins, cokes, carbon fibers, silicon, silicon oxide (SiO x ), silicon-carbon composites, silicon alloys, metals, titanium oxides, lithium-titanium oxides, metal alloys, and mixtures of these with carbon-based materials; The additive is an alkylene oxide adduct of an alkyl alcohol, an alkylene oxide adduct of an alkylene glycol, a glycol ether, an alkylene oxide adduct of a bisphenol, an ester compound, an amine compound, or an alcohol.

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