Electrode composition for secondary battery, electrode for secondary battery, and secondary battery

Abstract

To provide an electrode composition for a secondary battery that has a high adhesion strength between a current collector and an electrode and exhibits excellent durability of the battery under high-temperature conditions.SOLUTION: The electrode composition for a secondary battery includes an electrode active material, a binder resin, and a compound (A) having an ester group and a hydrophilic group, the compound (A) being an ester of an alcohol and a carboxylic acid, the saponification value of the compound (A) being 80 to 210, and the content of the compound (A) being 0.01 to 1.25% by weight based on the weight of the electrode composition for a secondary battery.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrode composition for a secondary battery, an electrode for a secondary battery, and 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, improvements in productivity and durability are required, and various technologies are being applied.

[0003] For example, Patent Document 1 discloses that an electrode slurry containing an electrode active material, a binder, and a solvent further contains carbonate esters.

[0004] Patent Document 2 describes a secondary battery slurry composition containing an alkylene oxide adduct A having a cloud point of 20 to 95°C as measured by the butyl diglycol method (BDG method), an alkylene oxide adduct B having a cloud point of 30°C or higher in an aqueous solution at an effective concentration of 1% by weight, and a dispersant composition containing polymer particles, and inorganic particles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-68280 [Patent Document 2] Patent No. 6152182 Summary of the Invention [Problem to be solved by the invention]

[0006] The electrode slurry of Patent Document 1 was effective in improving the stability of the slurry viscosity and the uniformity of the coating film, but did not take into consideration the adhesive strength between the current collector and the electrode. Furthermore, there was a risk that the carbonate ester in the electrode slurry would hydrolyze, adversely affecting the durability of the secondary battery at high temperatures.

[0007] The slurry composition of Patent Document 2 had the effect of improving dispersion stability, but not sufficiently. Furthermore, the addition of an alkylene oxide adduct to the slurry composition sometimes resulted in insufficient adhesive strength between the current collector and the electrode.

[0008] The present invention has been made to solve the above problems, and has an object to provide an electrode composition for a secondary battery that has high adhesive strength between a current collector and an electrode and is excellent in durability at high temperatures in the battery. [Means for solving the problem]

[0009] 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, comprising an electrode active material, a binder resin, and a compound (A) having an ester group and a hydrophilic group, wherein the compound (A) is an ester of an alcohol and a carboxylic acid, the saponification value of the compound (A) is 80 to 210, and the content of the compound (A) is 0.01 to 1.25% by weight based on the weight of the electrode composition for a secondary battery. A secondary battery electrode is obtained by compression molding the above secondary battery electrode composition. A secondary battery comprising the above secondary battery electrode. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an electrode composition for a secondary battery which has high adhesive strength between a current collector and an electrode and is excellent in durability at high temperatures in the battery. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. The present invention relates to an electrode composition for a secondary battery, an electrode for a secondary battery, and a secondary battery. The electrode composition for a secondary battery of the present invention may be an electrode composition for a lithium ion battery or an electrode composition for a sodium ion battery. In this specification, when lithium ion batteries and sodium ion batteries are mentioned, these concepts also include lithium ion secondary batteries and sodium ion secondary batteries, respectively. Hereinafter, the "secondary battery electrode composition" will also be referred to as the "electrode composition."

[0012] [Electrode composition] The electrode composition for a secondary battery of the present invention is an electrode composition for a secondary battery containing an electrode active material, a binder resin, and a compound (A) having an ester group and a hydrophilic group, wherein the compound (A) is an ester of an alcohol and a carboxylic acid, the saponification value of the compound (A) is 80 to 210, and the content of the compound (A) is 0.01 to 1.25 wt % based on the solids weight of the electrode composition for a secondary battery.

[0013] The electrode composition of the present invention may be an electrode composition for a positive electrode (also referred to as a positive electrode composition) or an electrode composition for a negative electrode (also referred to as a negative electrode composition). The electrode composition of the present invention itself does not contain an electrolyte solution, but as will be described later, an electrode layer for a secondary battery can be formed by adding an electrolyte solution to an electrode prepared using the electrode composition.

[0014] (electrode active material) The electrode active material may be a positive electrode active material or a negative electrode active material.

[0015] The positive electrode active material constituting the electrode composition for lithium ion batteries includes composite oxides of lithium and transition metals {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-yCo 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 having three or more transition metal elements [e.g., LiM a M’ b M’’ c O2 (M, M’, and M’’ are different transition metal elements respectively, 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 O2), etc.] etc., 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, and polyvinyl carbazole), etc. may be mentioned, and two or more kinds may be used in combination. In addition, the lithium-containing transition metal phosphate may be one in which a part of the transition metal site is substituted with another transition metal. When the electrode active material is a positive electrode active material, a composite oxide of lithium and a transition metal is preferable as the positive electrode active material.

[0016] The positive electrode active material constituting the electrode composition for a sodium ion battery is not particularly limited as long as it can be used in a sodium ion battery. Specifically, layered active materials, spinel-type active materials, oxoacid salt active materials, etc. may be mentioned. For example, NaFeO2, NaNiO2, NaCoO2, NaCrO2, NaMnO2, NaVO2, Na(Ni X Mn 1-X )O2 (0 < X < 1), Na(Fe X Mn 1-X )O2 (0 < X < 1), NaVPO4F, Na2FePO4F, Na3V2(PO4)3, etc. may be mentioned. Preferably, they are NaCoO2 and NaCrO2.

[0017] Examples of the negative electrode active material constituting the electrode composition for lithium ion batteries 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 alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon-manganese alloy, silicon-copper alloy, silicon-tin alloy, etc.), conductive polymers (for example, polyacetylene and polypyrrole), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide, lithium-titanium oxide, etc.) and metal alloys (for example, lithium-tin alloy, lithium-aluminum alloy, lithium-aluminum-manganese alloy, etc.), and mixtures of these with carbon-based materials, and two or more of these may be used in combination. 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.

[0018] As the negative electrode active material constituting the electrode composition for a sodium ion battery, the carbon-based material, silicon-based material, conductive polymer, metal, metal oxide, and metal alloy exemplified as the negative electrode active material constituting the electrode composition for a lithium ion battery can be used. However, among the materials exemplified above, the lithium-containing materials can be replaced with a material containing sodium, such as silicon-sodium alloy, sodium-titanium oxide, sodium-tin alloy, sodium-aluminum alloy, and sodium-aluminum-manganese alloy.

[0019] Among the particles of the negative electrode active material, those that do not contain lithium, lithium ions, sodium, or sodium ions inside may be subjected to a pre-doping treatment in which lithium, lithium ions, sodium, or sodium ions are contained in part or all of the particles of the negative electrode active material in advance.

[0020] From the viewpoint of increasing the electric capacity, the negative electrode active material is preferably non-graphitizable carbon or a mixture of non-graphitizable carbon and a silicon-based material.

[0021] The content of the electrode active material in the electrode composition is not particularly limited, but from the viewpoint of increasing the electrode density and thereby increasing the battery capacity, a high content of the electrode active material is preferable, and is preferably 78 to 97 wt % based on the solid content weight of the electrode composition, and more preferably 90 to 97 wt %.

[0022] (binder resin) The binder resin is a resin used in lithium ion batteries or sodium ion batteries, and examples thereof include starch, polyvinylidene fluoride (PVDF), polyvinyl alcohol, polyvinylpyrrolidone, polytetrafluoroethylene, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyethylene, and polypropylene, and two or more types may be used in combination. When the electrode composition contains these substances, it is considered to contain a binder resin. In this specification, the binder resin is a substance that is distinguished from the compound (A).

[0023] Furthermore, many binder resins have a weight average molecular weight (Mw) of more than 50,000. The weight average molecular weight of the binder resin 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" 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

[0024] The content of the binder resin is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, based on the weight of the solid content of the electrode composition.

[0025] (Conductive additive) The electrode composition for a secondary battery 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 (AB), ketjen black, furnace black, channel black, thermal lamp black, etc.), carbon nanofibers (CNF), carbon nanotubes (CNT), etc.), and mixtures thereof, or two or more of these may be used in combination. The conductive additive is preferably acetylene black or carbon nanotubes. 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 15 μm or more are considered to be negative electrode active materials, and those with a volume average particle diameter of less than 15 μm are considered to be conductive additives.

[0026] The content of the conductive assistant is preferably 1 to 5% by weight, more preferably 1 to 3% by weight, based on the weight of the solid content of the electrode composition.

[0027] (Compound (A)) Compound (A) is an ester of an alcohol and a carboxylic acid, and has an ester group and a hydrophilic group. Examples of the alcohol include alkyl alcohols such as methanol; alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, polyethylene glycol, and polypropylene glycol; trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, sorbitan, sorbitol, sucrose, and mannitol. Preferred alcohols are polyhydric alcohols, with alkylene glycols, glycerin, and sorbitan being more preferred. Preferred alkylene glycols are ethylene glycol, diethylene glycol, and polyethylene glycol.

[0028] Examples of carboxylic acids include fatty acids having 12 to 20 carbon atoms, such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; and aromatic carboxylic acids, such as benzoic acid, phthalic acid, and isophthalic acid. Preferred are lauric acid, stearic acid, oleic acid, and benzoic acid.

[0029] Compound (A) may be an alkylene oxide adduct. Examples of alkylene oxides (AO) include ethylene oxide (EO), propylene oxide (PO), butylene oxide, etc. The alkylene oxide added to compound (A) is preferably ethylene oxide.

[0030] When compound (A) is an ethylene oxide adduct, the ethylene oxide content (EO content: the number of millimoles of EO contained in 1 g of compound (A)) is not particularly limited, but is preferably 2.5 to 15.0 mmol / g, and more preferably 5.0 to 15.0 mmol / g. The ethylene oxide content can be determined by the following procedure. First, the molecular weight of the compound (A) is determined by the method described below. Next, the number of moles of ethylene oxide added is calculated from the proton ratio of CH2 derived from ethylene oxide relative to the proton ratio of linear / cyclic alkyl in the alcohol or carboxylic acid, and the formula weight of the (poly)ethylene oxide portion is determined. Finally, the EO content is calculated using the following formula. EO content of compound (A) (mmol / g)=(formula weight of (poly)ethylene oxide moiety in compound (A)) / (molecular weight of compound (A)×formula weight of ethylene oxide)×1000 (Example: Compound (A) No. 1) (44×7) / (534×44)×1000=13.1mmol / g

[0031] The number of ester groups in the compound (A) is not particularly limited, and may be one or more. The hydrophilic group contained in the compound (A) is a hydroxyl group or an oxyalkylene group.

[0032] The compound (A) preferably has a hydroxyl group as a hydrophilic group and satisfies the following (1) or (2): An electrode obtained using an electrode composition containing such a compound (A) tends to have a high peel strength at the interface between the current collector and the electrode layer. (1) The hydrophilic group further contains a polyoxyethylene group, and the average number of repeating oxyethylene groups in the polyoxyethylene group is 2 or more and less than 10. (2) It does not have a polyoxyethylene group as a hydrophilic group.

[0033] The compound (A) may be a single compound or a mixture of two or more compounds.

[0034] The compound (A) has a saponification value of 80 to 210. When the saponification value is within the above range, the compound (A) is less likely to be hydrolyzed, and the high-temperature durability of the battery is excellent. The compound (A) preferably has a saponification value of 80 to 169. The saponification value is a value measured according to JIS K0070 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0035] The acid value of the compound (A) is not particularly limited, but is preferably 0.01 to 15 mgKOH / g. The acid value of the compound (A) is a value measured according to JIS K0070 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0036] The compound (A) preferably has an HLB value of 7.2 or more and less than 13.0. When the HLB value is within the above range, the electrode composition of the present invention suffers little decrease in slurry viscosity over time and has excellent storage stability. The HLB value is a value that indicates the balance between hydrophilicity and lipophilicity, and the higher the HLB value, the higher the inorganicity. The HLB value is known as a value calculated by the Oda method, for example, as described in "Introduction to Surfactants," 2007, Sanyo Chemical Industries, Ltd., by Takehiko Fujimoto, p. 212. In the present invention, the HLB value, in the case of a single compound, is a value calculated using the following formula (1) from the ratio of the organic value to the inorganic value of the organic compound. HLB value = 10 × (inorganic / organic) (1) In formula (1), the number in parentheses represents the ratio of inorganic to organic components of the organic compound, and this ratio can be calculated from the values ​​given in the table on page 213 of the above-mentioned document. When compound (A) is a mixture of two or more compounds, the HLB value of compound (A) can be calculated by weighted averaging.

[0037] The HLB value of compound (A) can be adjusted to 7.2 or more and less than 13.0 by selecting the type of alcohol and the type of alkylene oxide and adjusting the number of moles of alkylene oxide added. When the electrode composition of the present invention contains two or more types of compound (A), the HLB value of each may be outside the above range, as long as the average of these falls within the above range.

[0038] The compound (A) preferably has a molecular weight of 300 to 1200, more preferably 350 or more and less than 1000. When the molecular weight is within the above range, the electrolyte solution can easily permeate into the electrode obtained using the electrode composition of the present invention. The molecular weight of compound (A) is the molecular weight calculated from the structural formula and the monomer ratio of the material when compound (A) is a single compound, and is the weight average molecular weight when compound (A) is a mixture of two or more compounds. The weight average molecular weight of compound (A) can be measured in the same way as the weight average molecular weight of the binder resin.

[0039] The content of compound (A) is 0.01 to 1.25% by weight, preferably 0.5 to 1.25% by weight, based on the weight of the solid content of the electrode composition for secondary batteries. When the content of compound (A) is within the above range, the dispersion stability of the electrode composition slurry is excellent. When the electrode composition for a secondary battery contains a conductive auxiliary, the content of the compound (A) is preferably 20 to 120% by weight, more preferably 40 to 110% by weight, based on the weight of the conductive auxiliary.

[0040] [Electrode for secondary batteries] The secondary battery electrode of the present invention is produced by compression molding the secondary battery electrode composition of the present invention. The secondary battery electrode may be a lithium ion battery electrode or a sodium ion battery electrode. The method for compression molding the secondary battery electrode composition is not particularly limited, and methods such as roll pressing, pressing with a press, etc. can be used. The electrode density of the secondary battery electrode obtained by compression molding the secondary battery electrode composition is preferably 1.0 to 2.0 g / ml when the electrode is a negative electrode. When the electrode is a positive electrode, the content is preferably 3.0 to 4.0 g / ml in the case of a positive electrode for a lithium ion battery, and 2.5 to 3.5 g / ml in the case of a positive electrode for a sodium ion battery. The electrode density defined here means the density in a state where the electrolyte has not been permeated into the electrode composition for a secondary battery. A secondary battery electrode obtained using the secondary battery electrode composition of the present invention has high electrode density and yet is excellent in electrolyte permeability.

[0041] [Secondary battery] The secondary battery of the present invention comprises the secondary battery electrode of the present invention. In the secondary battery of the present invention, the electrolyte solution is sufficiently permeated into the secondary battery electrode of the present invention.

[0042] Examples of secondary batteries include lithium ion batteries and sodium ion batteries.

[0043] The secondary battery of the present invention is equipped with the secondary battery electrode of the present invention, and since the electrolyte solution is sufficiently permeated into the electrode, it has excellent charge / discharge efficiency (Coulomb efficiency) and direct current resistance (DCR).

[0044] Known materials can be used for the components of the secondary battery of the present invention other than the electrodes for the secondary battery. That is, known materials can be used as the materials for the current collector, the electrolyte, the separator, and the like. As the electrolyte, it is preferable to use a non-aqueous solvent such as ethylene carbonate, diethyl carbonate, or propylene carbonate. As the electrolyte contained in the electrolytic solution, electrolytes used in known electrolytic solutions can be used. For example, in the case of a lithium ion battery, a lithium salt can be used, and in the case of a sodium ion battery, a sodium salt can be used.

[0045] Examples of lithium salts include 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.

[0046] Examples of sodium salts include inorganic sodium salts such as NaPF6, NaBF4, NaClO4, and NaAsF6, and organic sodium salts such as NaCF3SO3, NaN(CF3SO2)2, NaN(C2F5SO2)2, NaN(FSO2)2, and NaC(CF3SO2)3. Of these, NaPF6 is preferred from the viewpoint of battery output and charge / discharge cycle characteristics.

[0047] 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.

[0048] In the secondary battery of the present invention, only the positive electrode may be composed of the secondary battery electrode of the present invention, only the negative electrode may be composed of the secondary battery electrode of the present invention, or both the positive electrode and the negative electrode may be composed of the secondary battery electrode of the present invention.

[0049] 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.

[0050] The present specification discloses the following:

[0051] The present disclosure (1) is an electrode composition for a secondary battery containing an electrode active material, a binder resin, and a compound (A) having an ester group and a hydrophilic group, wherein the compound (A) is an ester of an alcohol and a carboxylic acid, the saponification value of the compound (A) is 80 to 210, and the content of the compound (A) is 0.01 to 1.25 wt % based on the solid content weight of the electrode composition for a secondary battery.

[0052] The present disclosure (2) is the electrode composition for a secondary battery according to the present disclosure (1), in which the saponification value of the compound (A) is 80 to 169.

[0053] The present disclosure (3) is the electrode composition for a secondary battery according to the present disclosure (1) or (2), characterized in that the compound (A) has a hydroxyl group as the hydrophilic group and satisfies the following (1) or (2): (1) The hydrophilic group further contains a polyoxyethylene group, and the average number of repeating oxyethylene groups in the polyoxyethylene group is 2 or more and less than 10; (2) The hydrophilic group does not have a polyoxyethylene group.

[0054] The present disclosure (4) is the electrode composition for a secondary battery according to any one of the present disclosures (1) to (3), in which the HLB value of the compound (A) is 7.2 or more and less than 13.0.

[0055] The present disclosure (5) is the electrode composition for a secondary battery according to any one of the present disclosures (1) to (4), in which the molecular weight of the compound (A) is 350 or more and less than 1,000.

[0056] The present disclosure (6) is the electrode composition for a secondary battery according to any one of the present disclosures (1) to (5), further containing a conductive aid, wherein the content of the electrode active material is 78 to 97 wt % based on the solid content weight of the electrode composition for a secondary battery, the content of the binder resin is 1 to 20 wt % based on the solid content weight of the electrode composition for a secondary battery, and the content of the conductive aid is 1 to 5 wt % based on the solid content weight of the electrode composition for a secondary battery.

[0057] The present disclosure (7) is the electrode composition for a secondary battery according to the present disclosure (6), in which the content of the compound (A) is 20 to 120% by weight based on the weight of the conductive assistant.

[0058] The present disclosure (8) is an electrode for a secondary battery obtained by compression molding the electrode composition for a secondary battery according to any one of the present disclosures (1) to (7).

[0059] The present disclosure (9) is a secondary battery including the electrode for secondary batteries according to the present disclosure (8). [Example]

[0060] 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.

[0061] (Preparation of Compounds (A) Nos. 1 to 16) The following Compounds (A) Nos. 1 to 16 were prepared. The starting materials for Compounds (A) Nos. 1 to 16, namely, alcohol, carboxylic acid, number of ester groups, presence or absence of OH groups, average number of repeating oxyethylene groups (EO), ethylene oxide (EO) content, acid value, HLB, molecular weight, and saponification value, are shown in Table 1. Among the carboxylic acids, the compositions of fatty acids (I) and fatty acids (II) containing two or more fatty acids are shown in Table 2. (Compound (A) No. 1) Benzoic acid was esterified with commercially available polyethylene glycol to obtain Compound (A) No. 1. The number of ester groups was 2, and the EO content was 13.1 mmol / g. (Compound (A) No. 2) A commercially available polyethylene glycol was esterified with a fatty acid (I) consisting mainly of oleic acid [TFA-125, manufactured by Tsuno Foods Co., Ltd.] to obtain Compound (A) No. 2. The number of ester groups was 1, and the EO content was 13.2 mmol / g.

[0062] (Compound (A) No. 3) A commercially available polyethylene glycol was esterified with fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Co., Ltd.] to obtain Compound (A) No. 3. The number of ester groups was 2, and the EO content was 9.4 mmol / g. (Compound (A) No. 4) Glycerin was esterified with fatty acid (II) [TFA-S70, manufactured by Tsuno Foods Co., Ltd.], which mainly consisted of stearic acid, to obtain Compound (A) No. 4. The number of ester groups was one.

[0063] (Compound (A) No. 5) Diethylene glycol was esterified with fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Co., Ltd.] to obtain Compound (A) No. 5. The number of ester groups was 1, and the EO content was 5.1 mmol / g. (Compound (A) No. 6) A commercially available polyethylene glycol was esterified with a fatty acid (I) consisting mainly of oleic acid [TFA-125, manufactured by Tsuno Foods Co., Ltd.] to obtain Compound (A) No. 6. The number of ester groups was 1, and the EO content was 9.6 mmol / g.

[0064] (Compound (A) No. 7) A commercially available polyethylene glycol was esterified with a fatty acid (I) consisting mainly of oleic acid [TFA-125, manufactured by Tsuno Foods Co., Ltd.] to obtain Compound (A) No. 7. The number of ester groups was two, and the EO content was 10.8 mmol / g. (Compound (A) No. 8) Sorbitan was esterified with a fatty acid mainly consisting of lauric acid (lauric acid manufactured by Fujifilm Wako Pure Chemical Industries, lauric acid content 95% or more) to obtain Compound (A) No. 8. The number of ester groups was 1.

[0065] (Compound (A) No. 9) Benzoic acid was esterified with commercially available polyethylene glycol to obtain Compound (A) No. 9. The number of ester groups was 2, and the EO content was 15.0 mmol / g. (Compound (A) No. 10) Ethylene glycol was esterified with fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Industries Co., Ltd.] to obtain Compound (A) No. 10. The number of ester groups was 1, and the EO content was 2.9 mmol / g.

[0066] (Compound (A) No. 11) A commercially available polyethylene glycol was esterified with a fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Industries Co., Ltd.] to obtain Compound (A) No. 11. The number of ester groups was 2, and the EO content was 16.6 mmol / g. (Compound (A) No. 12) A commercially available polyethylene glycol was esterified with a fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Industries Co., Ltd.] to obtain Compound (A) No. 12. The number of ester groups was 1, and the EO content was 18.7 mmol / g.

[0067] (Compound (A) No. 13) Glycerin was esterified with fatty acid (II) consisting mainly of stearic acid [TFA-S70, manufactured by Tsuno Foods Industries Co., Ltd.] to obtain Compound (A) No. 13. The number of ester groups was two. (Compound (A) No. 14) Phenoxyethanol was designated as Compound (A) No. 14. The number of ester groups was 0, and the EO content was 7.2 mmol / g.

[0068] (Compound (A) No. 15) An autoclave was charged with 100 g of hydrogenated castor oil (weight-average molecular weight 940) and 0.3 g of potassium hydroxide, and then 94 g of ethylene oxide (EO) was added to yield Compound (A) No. 15. Compound (A) No. 15 had 3 ester groups, an EO content of 14.8 mmol / g, and an average number of moles of EO added of 40. (Compound (A) No. 16) Ethylene oxide (EO) was added to commercially available polyethylene glycol to produce an ethylene oxide adduct, which was then esterified with fatty acid (I) consisting mainly of oleic acid [TFA-125, manufactured by Tsuno Foods Industries Co., Ltd.] to obtain Compound (A) No. 16. The compound had one ester group and an EO content of 15.3 mmol / g.

[0069] [Table 1]

[0070] In Table 1, compounds (A) marked with an * are comparative examples outside the scope of the present invention. In Table 1, (I / O) stands for "inorganic / organic," and the HLB values ​​in Table 1 were calculated using the above formula (1). Compounds (A) Nos. 1, 3, 7, 9, and 11 were converted to diesters by adding two or more equivalents of carboxylic acid to one equivalent of alcohol, while compounds (A) Nos. 2, 5, 6, 10, 12, and 16 were converted to monoesters by adding one equivalent of carboxylic acid to one equivalent of alcohol.

[0071] [Table 2]

[0072] In Table 2, the values ​​are rounded off and therefore do not add up to 100% by weight.

[0073] (Preparation of positive electrode active material) The following positive electrode active materials were prepared. NCA:LiNi 0.8 Co 0.15 Al 0.05 O2 ("HED NCA 7050", manufactured by BASF Toda Battery Materials LLC, volume average particle size (Dv50) 6.6 μm) NaCrO2: Sodium chromite (manufactured by Kojundo Chemical Laboratory)

[0074] (Preparation of negative electrode active material) The following negative electrode active materials were prepared. Graphite: Artificial graphite (FSN-1, manufactured by Shanshan in China, D50 particle size: 15.3 μm) HC: Hard carbon (Carbotron (registered trademark) PS (F), manufactured by Kureha Battery Materials Japan Co., Ltd., D50 particle size: 20 μm)

[0075] (Examples 1 to 10, 13, Comparative Examples 1 to 6, 9: Preparation of Slurry of Negative Electrode Composition for Lithium Ion Batteries) 2.0 parts by weight of acetylene black (AB: "Denka Black Li100", manufactured by Denka Co., Ltd., average primary particle size: 35 nm) as a conductive additive, 2.5 parts by weight of carboxymethyl cellulose (CMC) 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).

[0076] Next, 2.5 parts by weight of styrene butadiene rubber (SBR) as a binder resin was added, and the mixture was stirred for 5 minutes at 2000 rpm using a mixer. To the resulting dispersion, graphite in the amounts shown in Tables 3 and 4, 1.0 part by weight of each compound (A) (except for Comparative Example 9, which contained no compound (A)), and 60.0 parts by weight of ion-exchanged water were added as negative electrode active materials, and the mixture was stirred for 5 minutes at 2000 rpm using a mixer to prepare a negative electrode composition slurry. In Example 13, no conductive additive was added, and 1.75 parts by weight of CMC and 1.75 parts by weight of SBR (total amount: 3.5 parts by weight) were used, the amount of negative electrode active material was 96.0 parts by weight, and the amount of compound (A) shown in Table 3 was 0.5 parts by weight. Otherwise, a negative electrode composition slurry was prepared in the same manner as in Example 1, etc.

[0077] (Examples 11 to 12, Comparative Examples 7 to 8, and 10: Preparation of Slurry of Positive Electrode Composition for Lithium Ion Batteries) 1.0 part by weight of each compound (A) shown in Tables 3 and 4 (except for Comparative Example 10, which did not contain compound (A)) 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 (Awatori Mixer [manufactured by Thinky Corporation]). Next, 2.0 parts by weight of polyvinylidene fluoride (PVDF, manufactured by Kishida Chemical) as a binder resin was added, and stirring was continued for 5 minutes using the Awatori Mixer at 2000 rpm.

[0078] Further, NCA in the amounts shown in Tables 3 and 4 was added as a positive electrode active material, and 2.0 parts by weight of acetylene black {AB: "Denka Black Li100", manufactured by Denka Co., Ltd., average primary particle size: 35 nm} or 1.0 part by weight of carbon nanotubes (CNT: "K-Nanos100P", manufactured by Kumho Co., Ltd., outer diameter: 10 to 15 nm) as a conductive additive. The mixture was then stirred at 2000 rpm for 4 minutes using a mixer to prepare a positive electrode composition slurry.

[0079] (Examples 14 to 23 and Comparative Examples 11 to 17: Preparation of Slurry of Negative Electrode Composition for Sodium Ion Battery) A negative electrode composition slurry was prepared in the same manner as in Examples 1 to 10 and 13 and Comparative Examples 1 to 6 and 9, except that the negative electrode active material was changed to hard carbon and the contents of each component were as shown in Tables 5 and 6.

[0080] (Examples 24 to 25, Comparative Examples 18 to 20: Preparation of Slurry of Positive Electrode Composition for Sodium Ion Battery) A positive electrode composition slurry was prepared in the same manner as in Examples 11 to 12 and Comparative Examples 7 to 8 and 10, except that the positive electrode active material was changed to NaCrO2 and the contents of each component were as shown in Tables 5 and 6.

[0081] <Viscosity> The slurry obtained above was stored in a sealed container at room temperature, and the viscosity was measured using a rotational viscometer immediately after slurry preparation and 24 hours after the slurry preparation. The slurry viscosity retention rate was calculated from the measured viscosity. The results are shown in Tables 3, 4, 5, and 6.

[0082] (Preparation of Lithium Ion Battery Negative Electrodes Using Lithium Ion Battery Negative Electrode Compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9) The slurries of the negative electrode compositions obtained above in Examples 1 to 10 and 13 and Comparative Examples 1 to 6 and 9 were applied to one side of a current collector (copper foil) using a wire bar in the atmosphere and pre-dried overnight in a draft to form a negative electrode layer on the current collector. (Hereinafter, the current collector and negative electrode layer will be collectively referred to as the electrode sheet.) The electrode sheet was then punched out near the center to a diameter of 16 mm, further dried under reduced pressure (1.3 kPa) at 100°C for 2 hours, and pressed in a press to the desired electrode density (electrode thickness) to produce a negative electrode. The electrode sheet was cut with a cutter to a length of 8.0 cm and a width of 2.5 cm, dried in a vacuum dryer at 80°C for 3 hours, and then pressed with a roll press (manufactured by Tester Sangyo Co., Ltd.) to an electrode density of 1.6 g / cm. 3 The electrode (negative electrode) for measuring the peel strength was prepared by pressing the electrode so that the peel strength was 100%.

[0083] (Preparation of Lithium Ion Battery Positive Electrodes Using Lithium Ion Battery Positive Electrode Compositions of Examples 11 to 12 and Comparative Examples 7 to 8 and 10) The slurries of the positive electrode compositions of Examples 11 and 12 and Comparative Examples 7, 8, and 10 were applied to one side of a current collector (aluminum foil) using a wire bar in the atmosphere and pre-dried overnight in a draft to form a positive electrode layer on the current collector. (Hereinafter, the current collector and positive electrode layer will be collectively referred to as the electrode sheet.) The electrode sheet was then punched out near the center to a diameter of 16 mm, dried at 100°C for 2 hours, and pressed in a press to produce a positive electrode. The electrode sheet was cut with a cutter to a length of 8.0 cm and a width of 2.5 cm, dried in a vacuum dryer at 80°C for 3 hours, and then pressed with a roll press (manufactured by Tester Sangyo Co., Ltd.) to an electrode density of 3.2 g / cm. 3 The electrode (positive electrode) for measuring the peel strength was prepared by pressing the electrode so that the adhesive strength was 100%.

[0084] (Preparation of sodium ion battery negative electrodes using sodium ion battery negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17) The negative electrodes were prepared in the same manner as in Examples 1 to 10 and 13 and Comparative Examples 1 to 6 and 9. At this time, the electrode density was 1.2 g / cm 3 The electrode (negative electrode) for measuring the peel strength was prepared by pressing the electrode so that the peel strength was 100%.

[0085] (Preparation of sodium ion battery positive electrodes using sodium ion battery positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20) The positive electrodes were prepared in the same manner as in Examples 11 and 12 and Comparative Examples 7, 8, and 10. The electrode density was 2.7 g / cm 3 The electrode (positive electrode) for measuring the peel strength was prepared by pressing the electrode so that the adhesive strength was 100%.

[0086] <Peel strength (adhesion strength)> 1.Interfacial fracture test A Nichiban NISTACK (heavy-duty type: model number NW-K15) was attached to the electrode layer of the electrode prepared for peel strength measurement. The area to be gripped by the chuck of a benchtop precision universal testing machine (Autograph AGS-X, Shimadzu Corporation) during the peel test was covered with an additional NISTACK. In the autograph test, the uncoated current collector was placed on the bottom, and the NISTACK-covered area was gripped with the top chuck, and an interfacial fracture test was performed. A 20 N test jig was used, and the tensile speed was 150 mm / min. The force at which the current collector and electrode layer peeled was measured in accordance with JIS K 6854-2:1999 to determine the average peel force (N). The average peel force was divided by the width of the test piece (0.025 m) to record the interfacial fracture force (N / m). 2. Cohesive failure test After the interfacial fracture test, a NICE TACK was attached to the electrode layer side from which the current collector had peeled off, in the same manner as in the interfacial fracture test, and chucks were created on both the top and bottom with tape. A cohesive fracture test was performed in which the chucks attached on both sides with NICE TACK were pulled to destroy the electrode itself. A 20 N test jig was used, and the pulling speed was 150 mm / min. The force at which the electrode cracked was measured in accordance with JIS K 6854-2:1999 to determine the average peel force (N). The average peel force was divided by the width of the test piece (0.025 m) and recorded as the cohesive fracture force (N / m).

[0087] <Electrolyte permeability> 50 μL of the electrolyte solution was dropped onto the electrode prepared above, and the time (minutes) until the electrolyte solution permeated into the electrode was measured. The shorter the time until the electrolyte solution permeated, the better the permeability. When electrolyte is dropped onto the electrode, the color of the area where the electrolyte is dropped becomes darker. The color returns to normal as the electrolyte soaks into the electrode, so we measured the time it took for the electrode's color to return to normal. The measurement results are shown in Tables 3, 4, 5 and 6. The following two types of electrolyte were used: Electrolyte 1 (EC / DEC=1 / 1 (volume ratio), LiPF61M) was used. Electrolyte 2 (EC / DEC=1 / 1 (volume ratio), NaPF61M) was used. EC stands for ethylene carbonate, DEC stands for diethyl carbonate, LiPF6 stands for lithium hexafluorophosphate, and NaPF6 stands for sodium hexafluorophosphate.

[0088] (Making lithium-ion batteries) 1. Preparation of lithium ion batteries using negative electrode compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9 1.1 Preparation of positive electrode for battery evaluation A mixture (solid content: 10 wt%) was prepared by mixing 90 parts by weight of NCA as a positive electrode active material, 5.0 parts by weight of AB as a conductive additive, and 5.0 parts by weight of PVDF as a binder with NMP. The mixture was stirred at 2000 rpm for 1 minute using a planetary stirring mixer (Thinky Mixer, manufactured by THINKY CORPORATION) to prepare a slurry for the positive electrode layer. The obtained slurry was applied to one side of a current collector {carbon-coated aluminum foil [product name "Carbon-Coated Aluminum Foil"], manufactured by Toyo Aluminum Co., Ltd.} using a wire bar in the atmosphere, pre-dried overnight in a draft, and then punched out to a size of 16 mm diameter, dried at 100°C for 2 hours, and pressed in a press to prepare a positive electrode for battery evaluation.

[0089] 1.2 Battery construction From the positive electrode side, a positive electrode for battery evaluation, a separator [product name "#3501" manufactured by Celgard Inc.], and a negative electrode using a negative electrode composition of Examples 1 to 10 and 13 and Comparative Examples 1 to 6 and 9 were stacked in this order, electrolyte 1 was injected, and then the resultant was vacuum laminated to prevent oxygen from entering, thereby producing a lithium ion battery for use in charge / discharge tests.

[0090] 2. Preparation of Lithium-Ion Batteries Using the Positive Electrode Compositions of Examples 11-12 and Comparative Examples 7-8 and 10 2.1 Preparation of negative electrode for battery evaluation A mixture (solids concentration 10 wt%) was prepared by mixing 90.9 parts by weight of artificial graphite (FSN-1, manufactured by Shanshan China Co., Ltd.) as the negative electrode active material, 5.1 parts by weight of AB as the conductive additive, and 2.0 parts by weight of SBR and 2.0 parts by weight of CMC as the binder with water. The mixture was stirred at 2000 rpm for 1 minute using a planetary stirring mixer (Awatori Rentaro [manufactured by Thinky Corporation]) to prepare a slurry for the negative electrode layer. The obtained slurry was applied to one side of a current collector (copper foil) using a wire bar in the atmosphere, pre-dried overnight in a draft, and then punched out to a diameter of 16 mm, dried at 100°C for 2 hours, and pressed in a press to prepare a negative electrode for battery evaluation.

[0091] 2.2 Battery construction Lithium ion batteries were fabricated in the same manner as in 1.2 above, except that the positive electrodes using the positive electrode compositions of Examples 11 to 12 and Comparative Examples 7 to 8 and 10 and the negative electrodes for battery evaluation fabricated in 2.1 above were used.

[0092] <Measurement of initial output characteristics of lithium-ion batteries> At 45°C, using a charge / discharge measuring device "HJ-SD8" (manufactured by Hokuto Denko Corporation), evaluation was carried out by the following method on lithium ion batteries using the negative electrode compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9, and lithium ion batteries using the positive electrode compositions of Examples 11 to 12 and Comparative Examples 7 to 8, 10. The evaluation was carried out by placing the lithium ion batteries using the negative electrode compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9, and the lithium ion batteries using the positive electrode compositions of Examples 11 to 12 and Comparative Examples 7 to 8, 10 in a constant temperature bath at 45°C. The battery was charged to 4.2 V at 0.05 C using a constant current, constant voltage (CCCV) charging method, followed by a 10-minute pause and then discharged to 2.5 V at 0.05 C. It was then charged to 4.2 V at 0.05 C, paused for 10 minutes, and then discharged to 2.5 V at 1 C. The discharge capacity (%) at 1 C relative to the charge capacity at 0.05 C was defined as the initial output characteristics (1 C / 0.05 C). The results are shown in Tables 3 and 4.

[0093] <Measurement of high-temperature durability of lithium-ion batteries> At 70°C, using a charge / discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation], evaluation was carried out by the following method on lithium ion batteries using the negative electrode compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9, and lithium ion batteries using the positive electrode compositions of Examples 11 to 12 and Comparative Examples 7 to 8, 10. The evaluation was carried out by placing the lithium ion batteries using the negative electrode compositions of Examples 1 to 10, 13 and Comparative Examples 1 to 6, 9, and the lithium ion batteries using the positive electrode compositions of Examples 11 to 12 and Comparative Examples 7 to 8, 10 in a constant temperature bath at 70°C. The battery was charged to 4.2 V at a current of 0.05 C using a constant current, constant voltage (CCCV) charging method, and after a 10-minute rest, discharged to 2.5 V at a current of 0.05 C. This charge / discharge cycle was repeated 10 times, and the discharge capacity (%) at the 10th cycle relative to the discharge capacity at the 1st cycle was defined as the high-temperature durability (10 cycles). The results are shown in Tables 3 and 4.

[0094] [Table 3]

[0095] [Table 4]

[0096] (Making sodium-ion batteries) 1. Preparation of sodium ion batteries using negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17 1.1 Preparation of positive electrode for battery evaluation 290 parts by weight of NaCrO as a positive electrode active material, 5.0 parts by weight of AB as a conductive additive, and 5.0 parts by weight of PVDF as a binder were mixed with NMP to obtain a mixed solution (solid content concentration 10 wt%). The mixed solution was stirred at 2000 rpm for 1 minute using a planetary stirring mixer (Awatori Rentaro [manufactured by Thinky Corporation]) to prepare a slurry for the positive electrode layer. The obtained slurry was applied to one side of a current collector {carbon-coated aluminum foil [product name "Carbon-Coated Aluminum Foil"], manufactured by Toyo Aluminum Co., Ltd.} using a wire bar in the atmosphere, pre-dried overnight in a draft, and then punched out to a size of 16 mm diameter, dried at 100°C for 2 hours, and pressed in a press to prepare a positive electrode for battery evaluation.

[0097] 1.2 Battery construction From the positive electrode side, a positive electrode for battery evaluation, a separator [product name "#3501" manufactured by Celgard Inc.], and negative electrodes using the negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17 were stacked in this order, electrolyte 2 was injected, and then the resultant was vacuum laminated to prevent oxygen from entering, thereby producing a sodium ion battery for use in charge / discharge tests.

[0098] 2. Preparation of sodium ion batteries using the positive electrode compositions of Examples 24-25 and Comparative Examples 18-20 2.1 Preparation of negative electrode for battery evaluation A mixture (solids concentration 10 wt%) was prepared by mixing 90.9 parts by weight of hard carbon (Carbotron® PS(F), manufactured by Kureha Battery Materials Japan Co., Ltd.) as the negative electrode active material, 5.1 parts by weight of AB as the conductive additive, and 2.0 parts by weight of SBR and 2.0 parts by weight of CMC as binders with water. The mixture was stirred at 2000 rpm for 1 minute using a planetary stirring mixer (Thinky Mixer, manufactured by Awatori Rentaro Co., Ltd.) to prepare a slurry for the negative electrode layer. The obtained slurry was applied to one side of a current collector (copper foil) using a wire bar in the atmosphere, pre-dried overnight in a draft, and then punched out to a diameter of 16 mm, dried at 100°C for 2 hours, and pressed in a press to prepare a negative electrode for battery evaluation.

[0099] 2.2 Battery construction Examples Sodium ion batteries were fabricated in the same manner as in 1.2 above, except that positive electrodes using the positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20 and negative electrodes for battery evaluation fabricated in 2.1 above were used.

[0100] <Measurement of initial output characteristics of sodium-ion batteries> At 45°C, using a charge / discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation], sodium ion batteries using the negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17, and sodium ion batteries using the positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20 were evaluated by the following method. The evaluation was carried out by placing the sodium ion batteries using the negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17, and the sodium ion batteries using the positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20 in a constant temperature bath at 45°C. The battery was charged to 3.7 V at 0.05 C using a constant current, constant voltage (CCCV) charging method, followed by a 10-minute pause and then discharged to 2.5 V at 0.05 C. It was then charged to 4.2 V at 0.05 C, then, after a 10-minute pause, discharged to 2.5 V at 1 C. The discharge capacity (%) at 1 C relative to the charge capacity at 0.05 C was defined as the initial output characteristics (1 C / 0.05 C). The results are shown in Tables 5 and 6.

[0101] <Measurement of high-temperature durability of sodium-ion batteries> Using a charge / discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation] at 70°C, sodium ion batteries using the negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17, and sodium ion batteries using the positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20 were evaluated by the following method. The evaluation was carried out by placing the sodium ion batteries using the negative electrode compositions of Examples 14 to 23 and Comparative Examples 11 to 17, and the sodium ion batteries using the positive electrode compositions of Examples 24 to 25 and Comparative Examples 18 to 20 in a constant temperature bath at 70°C. The battery was charged to 3.7 V at a current of 0.05 C using a constant current, constant voltage (CCCV) charging method, and after a 10-minute rest, discharged to 2.5 V at a current of 0.05 C. This charge / discharge cycle was repeated 10 times, and the discharge capacity (%) at the 10th cycle relative to the discharge capacity at the 1st cycle was defined as the high-temperature durability (10 cycles). The results are shown in Tables 5 and 6.

[0102] [Table 5]

[0103] [Table 6]

[0104] The lithium ion battery electrode compositions, lithium ion battery electrodes, and lithium ion batteries of Examples 1 to 13 had higher adhesive strength between the current collector and the electrode and were superior in battery durability at high temperatures compared to the lithium ion battery electrode compositions, lithium ion battery electrodes, and lithium ion batteries of Comparative Examples 1 to 10. Examples 2 to 9 and 11 to 13, which contained Compounds (A) Nos. 2 to 9, were superior in battery durability at high temperatures compared to Examples 1 and 10. On the other hand, the sodium battery electrode compositions, sodium ion battery electrodes, and sodium ion batteries of Examples 14 to 25 had higher adhesive strength between the current collector and the electrode, and were superior in durability of the battery at high temperatures, compared to the sodium ion battery electrode compositions, sodium ion battery electrodes, and sodium ion batteries of Comparative Examples 11 to 20. Examples 2, 4 to 6, and 8 containing Compound (A) Nos. 2, 4 to 6, and 8 were particularly superior in peel strength at the interface between the current collector and the electrode compared to Examples 1, 3, 7, and 9 to 10. Compound (A) Nos. 2, 4 to 6, and 8 each had, as a hydrophilic group, either (1) a hydroxyl group and a polyoxyethylene group having an average repeating number of oxyethylene groups of 2 or more but less than 10, or (2) a hydroxyl group and no polyoxyethylene group. Examples 15, 17 to 19, and 21 in sodium ion batteries also had excellent peel strength at the interface between the current collector and the electrode. In Examples 1 to 4, 6 to 8, and 11 to 12, which contained Compounds (A) Nos. 1 to 4 and 6 to 8, each having an HLB value of 7.2 or more and less than 13.0, the viscosity of the electrode composition slurry was less likely to decrease after preparation, and the storage stability was excellent. Similarly, in Examples 14 to 17 and 19 to 21 in the sodium ion battery, the storage stability was also excellent. Examples 1 to 6, 8 to 9, and 11 to 13, which contained Compound (A) Nos. 1 to 6 and 8 to 9, each having a molecular weight of 350 or more and less than 1000, exhibited faster electrolyte permeation into the electrode than Examples 7 and 10. Similarly, Examples 14 to 19 and 21 to 22, which were sodium ion batteries, also exhibited faster electrolyte permeation into the electrode.

Claims

1. An electrode composition for a secondary battery comprising an electrode active material, a binder resin, and a compound (A) having an ester group and a hydrophilic group, the compound (A) is an ester of an alcohol and a carboxylic acid, The saponification value of the compound (A) is 80 to 210, The content of the compound (A) is 0.01 to 1.25% by weight based on the weight of the solid content of the electrode composition for secondary batteries.

2. 2. The electrode composition for a secondary battery according to claim 1, wherein the compound (A) has a saponification value of 80 to 169.

3. The electrode composition for a secondary battery according to claim 1 or 2, wherein the compound (A) has a hydroxyl group as the hydrophilic group and satisfies the following (1) or (2): (1) The hydrophilic group further contains a polyoxyethylene group, and the average number of repeating oxyethylene groups in the polyoxyethylene group is 2 or more and less than 10; (2) The hydrophilic group does not include a polyoxyethylene group.

4. 3. The electrode composition for a secondary battery according to claim 1, wherein the compound (A) has an HLB value of 7.2 or more and less than 13.

0.

5. 3. The electrode composition for a secondary battery according to claim 1, wherein the compound (A) has a molecular weight of 350 or more but less than 1,000.

6. Further, a conductive additive is contained, the content of the electrode active material is 78 to 97 wt % based on the solid content weight of the electrode composition for secondary batteries, the content of the binder resin is 1 to 20 wt % based on the solid content weight of the electrode composition for secondary batteries, 3. The electrode composition for a secondary battery according to claim 1, wherein the content of the conductive additive is 1 to 5% by weight based on the solid content weight of the electrode composition for a secondary battery.

7. 7. The electrode composition for a secondary battery according to claim 6, wherein the content of the compound (A) is 20 to 120% by weight based on the weight of the conductive additive.

8. 3. A secondary battery electrode obtained by compression molding the electrode composition for a secondary battery according to claim 1 or 2.

9. A secondary battery comprising the electrode for a secondary battery according to claim 8.

Images