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

Abstract

This electrode composition for a secondary battery comprises an electrode active material, a binder resin, and an additive, wherein the additive contains a compound (A) represented by general formula (1), and the hydroxyl value of the additive is at most 30 KOH mg / g. Formula (1): R1-O-(AO)m-R2 [In the formula, AO is a C2-C4 alkyleneoxy group, m is a number of 3-20 indicating the average number of repetitions of an alkyleneoxy group, and (AO)m is a polyoxyalkylene chain, the polyoxyalkylene chain includes an ethyleneoxy group, and the molar ratio of the ethyleneoxy group in the polyoxyalkylene chain is at least 90% with respect to the total number of moles of the alkyleneoxy group. R1 is a C1-C20 alkyl group, and R2 is a C1-C2 alkyl group.]

Description

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

[0001] The present invention relates to an electrode composition for a secondary battery, an electrode for a secondary battery, and a secondary battery.

[0002] Secondary batteries such as lithium-ion batteries are widely used in the field of portable information devices, including mobile phones and laptop computers. While the applications of secondary batteries continue to expand, their use in hybrid and electric vehicles, in addition to traditional applications, is also being considered, and some applications have already been put into practical use. To further popularize these applications, there is a demand for higher capacity and power output secondary batteries, and various technologies are being attempted.

[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 the 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 that improves electrolyte permeability by providing grooves on the electrode surface. Patent Document 2 describes that electrolyte impregnation is improved by including a specific nonionic surfactant such as polyethylene glycol monooleate in the electrode active material layer of the electrode.

[0005] JP 2008-27633 A Japanese Patent No. 5742561

[0006] However, the method of Patent Document 1 involves a process of pressing the electrode surface with a textured roller to create grooves, which necessitates the introduction of new equipment. Patent Document 2 discloses that initial charge / discharge efficiency is improved in batteries equipped with electrodes containing a nonionic surfactant such as polyethylene glycol monooleate in the electrode active material layer, but the impregnation or penetration of the electrolyte solution was not actually evaluated, leaving the effectiveness unclear. Furthermore, the present inventors have discovered a problem in that, although initial charge / discharge efficiency is improved in batteries equipped with electrodes containing the nonionic surfactant in the electrode active material layer, side reactions may occur during charge / discharge, gradually deteriorating battery performance (deteriorating charge / discharge efficiency and capacity).

[0007] The present invention solves the above-mentioned problems, and aims to provide an electrode composition for secondary batteries that can be used to produce electrodes that have excellent electrolyte permeability and high potential resistance, and whose battery performance does not deteriorate even after repeated charge and discharge.

[0008] The present inventors have arrived at the present invention as a result of extensive research. The present invention relates to any one of the following: An electrode composition for a secondary battery containing an electrode active material, a binder resin, and an additive, wherein the additive contains a compound (A) represented by the following general formula (1), and the hydroxyl value of the additive is 30 KOH mg / g or less. １ -O-(AO) ｍ -R ２ (1) [In the formula, AO is an alkyleneoxy group having 2 to 4 carbon atoms, m is a number of 3 to 20 representing the average number of repetitions of the alkyleneoxy group, and (AO) ｍ is a polyoxyalkylene chain, the polyoxyalkylene chain contains ethyleneoxy groups, and the molar ratio of the ethyleneoxy groups in the polyoxyalkylene chain is 90% or more based on the total number of moles of the alkyleneoxy groups. １ is an alkyl group having 1 to 20 carbon atoms, and R ２ is an alkyl group having 1 to 2 carbon atoms.] A secondary battery electrode obtained by compression molding the above secondary battery electrode composition. A secondary battery comprising the above secondary battery electrode.

[0009] According to the present invention, it is possible to provide an electrode composition for a secondary battery that can be used to produce an electrode that has excellent electrolyte permeability, high potential resistance, and does not deteriorate in battery performance even after repeated charge and discharge.

[0010] 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 "electrode composition for a secondary battery" will also be referred to as the "electrode composition."

[0011] <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 an additive, wherein the additive contains a compound (A) represented by the following general formula (1), and the hydroxyl value of the additive is 30 KOHmg / g or less. １ -O-(AO) ｍ -R ２ (1) [In the formula, AO is an alkyleneoxy group having 2 to 4 carbon atoms, m is a number of 3 to 20 representing the average number of repetitions of the alkyleneoxy group, and (AO) ｍ is a polyoxyalkylene chain, the polyoxyalkylene chain contains ethyleneoxy groups, and the molar ratio of the ethyleneoxy groups in the polyoxyalkylene chain is 90% or more based on the total number of moles of the alkyleneoxy groups. １ is an alkyl group having 1 to 20 carbon atoms, and R ２ is an alkyl group having 1 to 2 carbon atoms.

[0012] 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.

[0013] (Electrode Active Material) The electrode active material may be a positive electrode active material or a negative electrode active material.

[0014] The positive electrode active material constituting the electrode composition for lithium ion batteries is a composite oxide of lithium and a transition metal {composite oxide containing one type of transition metal (LiCoO ２ , LiNiO ２ , LiAlMnO ４ , LiMnO ２ and LiMn ２ O ４ etc.), composite oxides containing two transition metal elements (e.g., LiFeMnO ４ , LiNi １－ｘ Co ｘ O ２ , LiMn １－ｙ Co ｙ O ２ , LiNi １／３ Co １／３ Al １／３ O ２ and LiNi ０．８ Co ０．１５ Al ０．０５ O ２ ) and composite oxides containing three or more transition metal elements [e.g., LiM ａ M' ｂ M'' ｃ O ２ (M, M', and M'' are different transition metal elements, and a + b + c = 1 is satisfied. For example, LiNi ０．８ Co ０．１ Mn ０．１ O ２ , LiNi １／３ Mn １／３ Co １／３ O ２ ) etc.}, lithium-containing transition metal phosphates (e.g., LiFePO ４ , LiCoPO ４ , LiMnPO ４ and LiNiPO ４ ), transition metal oxides (e.g., MnO ２ and V ２ O ５ ), transition metal sulfides (e.g., MoS ２ and TiS ２) 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 be one in which part of the transition metal sites is substituted with another transition metal. When the electrode active material is a positive electrode active material, the positive electrode active material is preferably a composite oxide of lithium and a transition metal.

[0015] 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. Specific examples include layered active materials, spinel-type active materials, and oxoacid salt active materials. For example, NaFeO ２ , NaNiO ２ , NaCoO ２ , NaCrO ２ , NaMnO ２ , NaVO ２ , Na(Ni Ｘ Mn １－Ｘ ) O ２ (0<X<1), Na(Fe Ｘ Mn １－Ｘ ) O ２ (0<X<1), NaVPO ４ F, Na ２ FePO ４ F, Na ３ V ２ (P.O. ４ ) ３ etc. Preferably, NaCoO ２ and NaCrO ２ is.

[0016] 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 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, and two or more of these may be used in combination. When the electrode active material is a negative electrode active material, a carbon-based material is preferred as the negative electrode active material, and graphite or hard carbon is particularly preferred. When the negative electrode active material is graphite, the shape thereof is not particularly limited, and examples thereof include spherical graphite and scaly graphite.

[0017] 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 material can be replaced with a material containing sodium. Specific examples include a silicon-sodium alloy, sodium-titanium oxide, a sodium-tin alloy, a sodium-aluminum alloy, and a sodium-aluminum-manganese alloy.

[0018] 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.

[0019] 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.

[0020] 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 thus the battery capacity, a high content of the electrode active material is preferable, and it is preferably 90 to 98 wt % based on the solid content weight of the electrode composition. The "solid content weight of the electrode composition" refers to the weight of the material excluding volatile components such as organic solvents (the total weight of the electrode active material, binder resin, conductive aid, additives, etc.). Specifically, the solid content weight is the weight of the residue when the electrode composition is heated at 100°C for 8 hours.

[0021] (Binder Resin) The binder resin is a resin used in secondary batteries, and examples thereof include starch, polyvinylidene fluoride, polyvinyl alcohol, polyvinylpyrrolidone, polytetrafluoroethylene, styrene-butadiene rubber (SBR), polyethylene, and polypropylene, and two or more of these may be used in combination. The binder resin broadly includes thickeners, and examples of the thickener include carboxymethyl cellulose (CMC). 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).

[0022] The content of the binder resin (including the thickener) is preferably 2 to 8% by weight based on the weight of the solid content of the electrode composition.

[0023] (Additive) The additive in the present invention contains a compound (A) represented by the following general formula (1) and has a hydroxyl value of 30 KOHmg / g or less.

[0024] Compound (A) is a compound represented by the following general formula (1): １ -O-(AO) ｍ -R ２ (1) [In the formula, AO is an alkyleneoxy group having 2 to 4 carbon atoms, m is a number of 3 to 20 representing the average number of repetitions of the alkyleneoxy group, and (AO) ｍ is a polyoxyalkylene chain. １ is an alkyl group having 1 to 20 carbon atoms, and R ２ is an alkyl group having 1 to 2 carbon atoms.

[0025] In general formula (1), AO represents an alkyleneoxy group having 2 to 4 carbon atoms. Examples of the alkyleneoxy group having 2 to 4 carbon atoms include an ethyleneoxy group, a propyleneoxy group, and a butyleneoxy group. AO may be of one type alone or of two or more types. Of these, an oxyethylene group is preferred.

[0026] In general formula (1), m is a number from 3 to 20 representing the average number of repeating alkyleneoxy groups. If m is outside the above range, the electrolyte permeability of the resulting electrode will decrease. m is preferably a number from 5 to 17. When there are multiple types of alkyleneoxy groups, m is the sum of the average number of repeating alkyleneoxy groups.

[0027] (AO) ｍ is a polyoxyalkylene chain, the polyoxyalkylene chain contains an ethyleneoxy group, and the molar ratio of the ethyleneoxy group in the polyoxyalkylene chain is 90% or more based on the total number of moles of alkyleneoxy groups. When AO is an oxyethylene group or the ratio of oxyethylene groups in AO is high, the electrolyte permeability is improved. When the molar ratio of ethyleneoxy groups in the polyoxyalkylene chain is less than 90% based on the total number of moles of alkyleneoxy groups, the potential resistance is reduced, the initial coulomb efficiency is likely to be low, and battery performance tends to be easily reduced after repeated charge and discharge. The molar ratio of ethyleneoxy groups in the polyoxyalkylene chain is preferably 92% or more. Note that multiple AOs in the polyoxyalkylene chain may be the same or different. When there are two or more types of AO, they may be added in a block or random manner.

[0028] In general formula (1), R １ is an alkyl group having 1 to 20 carbon atoms. １ If the number of carbon atoms is 21 or more, the electrolyte permeability of the electrode and the battery performance (Coulomb efficiency, capacity retention rate, etc.) will be reduced.

[0029] The alkyl group having 1 to 20 carbon atoms may be linear or branched. Examples of the alkyl group having 1 to 20 carbon atoms include linear alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, and icosyl group; isopropyl group, isobutyl group, tert-butyl group, isopentyl group, isohexyl group, isoheptyl group, isooctyl group, isononyl group; Examples of branched alkyl groups include an isodecyl group, an isoundecyl group, an isododecyl group, an isotridecyl group, a 2-ethyldodecyl group, a 2-ethyltridecyl group, a 2-methyltetradecyl group, an isohexadecyl group, a 2-octylnonyl group, a 2-hexylundecyl group, a 2-ethylpentadecyl group, a 2-(3-methylhexyl)-7-methyl-nonyl group, an isooctadecyl group, a 1-hexyltridecyl group, a 2-ethylheptadecyl group, and an isoicosyl group. １ R may be an alkyl group having a distribution of carbon atoms (for example, a mixture of alkyl groups having 14 and 15 carbon atoms). １ is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 13 carbon atoms, and most preferably an alkyl group having 6 to 13 carbon atoms. If the number of carbon atoms is the same, a branched structure tends to have higher adsorption to the electrode active material than a linear structure, and tends to be more effective in improving electrolyte permeability.

[0030] In general formula (1), R ２ is an alkyl group having 1 to 2 carbon atoms (methyl group or ethyl group). ２ If the number of carbon atoms in R is 3 or more, the battery performance (Coulomb efficiency, capacity retention rate, etc.) may decrease, and further the electrolyte permeability of the electrode may also decrease. １ is preferably a methyl group.

[0031] The method for producing compound (A) is not particularly limited, and compound (A) can be produced by, for example, the following methods (i) and (ii): (i) a method in which the hydroxyl terminals of an alkyl alcohol AO adduct obtained by adding alkylene oxide (AO) to an alkyl alcohol having 1 to 20 carbon atoms are alkylated with an alkylating agent such as an alkyl chloride having 1 to 2 carbon atoms; (ii) a method in which two hydroxyl terminals of a polyalkylene glycol are alkylated with an alkylating agent such as an alkyl chloride; １ The number of carbon atoms and R ２ When compound (A) having a different number of carbon atoms from that of the compound (A) is to be produced, method (i) is preferred because it allows the target compound to be obtained more efficiently.

[0032] Examples of the alkyl alcohol having 1 to 20 carbon atoms include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol (isobutyl alcohol), 2-methyl-2-propanol (tert-butyl alcohol), 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2,2-dimethyl-1-propanol, 1-hexanol, 2-hexanol, and 2-methyl-1-pentanol. , 2-ethyl-2-butanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 1-nonanol, 2-nonanol, 3,5,5-trimethyl-1-hexanol, 1-decanol, isodecanol, 1-undecanol, 2-undecanol, 1-dodecanol, 1-tridecanol, isotridecanol, 1-tetradecanol, 1-pentadecanol, 1-hexadecanol, 1-heptadecanol, 1-octadecanol, 1-nonadecanol, and 1-eicosanol.

[0033] Examples of the alkyl chloride include methyl chloride (methyl chloride), ethyl chloride (ethyl chloride), propane chloride, butane chloride, pentane chloride, hexane chloride, heptane chloride, nonane chloride, decane chloride, and dodecane chloride.

[0034] The compound (A) may be used alone or in combination of two or more.

[0035] The hydroxyl value of the additive in the present invention is 30 KOHmg / g or less. If the hydroxyl value exceeds 30 KOHmg / g, the potential resistance of the additive decreases, the additive may decompose during charging and discharging of the battery, and further, the decomposition products of the additive may adversely affect other components constituting the electrode, resulting in decreased battery performance. The hydroxyl value of the additive is preferably 20 KOHmg / g or less. Note that the hydroxyl value of the additive in this specification is a value measured by a method in accordance with JIS K0070.

[0036] The additive of the present invention may contain a compound other than the compound (A) as long as the hydroxyl value of the entire additive is within a range of 30 KOH mg / g or less. The compound other than the compound (A) may be an alkyl alcohol AO adduct which is an intermediate product when producing the compound (A) by the method (i) above, or a compound having a structure represented by general formula (1) but having any of the characteristics of general formula (1) (the range of the average repeat number m of alkyleneoxy groups, the ratio of ethyleneoxy groups in the alkyleneoxy groups, R １ or the number of carbon atoms in R ２ The compound (A) is a compound that does not satisfy one or more of the above conditions (number of carbon atoms), or a polyalkylene glycol (such as PEG). The content of compounds other than compound (A) in the additive is preferably 45% by weight or less, and more preferably 30% by weight or less, based on the weight of the additive. The content of compound (A) and the content of compounds other than compound (A) in the additive can be analyzed by NMR or the like.

[0037] The content of the additive is preferably 0.01 to 2 wt %, more preferably 0.1 to 2 wt %, based on the weight of the electrode active material. When the content of the additive is within this range, the ratio of the additive to the electrode active material becomes appropriate, and the effects of including the additive can be suitably exhibited. Furthermore, the content of the additive is preferably 0.01 to 2 wt %, more preferably 0.1 to 2 wt %, based on the solids weight of the electrode composition for secondary batteries.

[0038] The electrode composition for a secondary battery of the present invention may contain a conductive aid in addition to the above-mentioned electrode active material, binder resin, and additives.

[0039] (Conductive Aid) Examples of the conductive aid include 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, and two or more of them may be used in combination.

[0040] Carbon-based materials are used both as negative electrode active materials and as conductive additives, but in the present application, those with a volume average particle diameter of 10 μm or more are considered to be negative electrode active materials, and those with a volume average particle diameter of less than 10 μm are considered to be conductive additives.

[0041] In this specification, the value of "volume average particle diameter (D50) of the negative electrode active material or conductive additive" means the 50% diameter value in the volume-based cumulative fraction determined by laser diffraction measurement method.

[0042] <Method for producing electrode composition for secondary battery> The electrode composition for secondary batteries of the present invention can be obtained by mixing an electrode active material, a binder resin (including a thickener), and additives, and, if necessary, other components (such as a conductive aid). The method and order of mixing the components are not particularly limited, but when both styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) are contained, it is preferable not to add and mix the SBR and CMC simultaneously from the viewpoint of uniformity of the electrode composition. For example, a method is preferred in which the electrode active material and CMC are stirred to homogenize, then the additives are added and mixed, and then the SBR is added and mixed. If necessary, a solvent (water or an organic solvent) may be added during each mixing step.

[0043] Compound (A), an essential component of the additive, has a polyoxyethylene chain of an appropriate chain length, and therefore exhibits affinity with the electrolyte solvent. Compound (A) also has an alkyl group bonded to the end of the polyoxyethylene chain, and therefore exhibits appropriate adsorption to the electrode active material surface. That is, compound (A) has appropriate affinity with both the electrolyte and the electrode active material surface, and is therefore thought to contribute to improving the electrolyte permeability into the electrode (electrode active material layer). Furthermore, the additive contained in the electrode composition for a secondary battery of the present invention has a hydroxyl group of 30 KOH mg / g or less and has high potential resistance (i.e., is less likely to decompose during charge and discharge), and is therefore thought to be less likely to cause problems such as a decrease in battery performance (Coulomb efficiency, capacity, etc.) even after repeated charge and discharge.

[0044] <Secondary Battery Electrode> The secondary battery electrode of the present invention is obtained by compression molding the secondary battery electrode composition of the present invention. The secondary battery electrode may be an electrode for a lithium ion battery or an electrode for a sodium ion battery. The method for compression molding the secondary battery electrode composition is not particularly limited, and 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 secondary battery electrode composition is 1.0 to 2.0 g / cm when the electrode is a negative electrode. ３ In addition, when the electrode is a positive electrode, in the case of a positive electrode for a lithium ion battery, it is preferably 3.0 to 4.0 g / cm ３ In the case of a positive electrode for a sodium ion battery, it is preferably 2.5 to 3.5 g / cm ３ It is preferable that the electrode for a secondary battery obtained using the electrode composition for a secondary battery of the present invention has excellent electrolyte permeability even in the case of a high electrode density, which generally tends to deteriorate the electrolyte permeability. 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.

[0045] When the electrode composition is a slurry electrode composition containing a solvent, it is preferable to remove the solvent by drying before compression molding (hereinafter, an electrode produced via a solvent-containing slurry electrode composition may be referred to as a "slurry electrode"). The secondary battery electrode of the present invention may be the above-mentioned slurry electrode, or may be an electrode produced by a dry process without using a solvent (hereinafter, may be referred to as a "dry electrode"). When the secondary battery electrode of the present invention is a dry electrode, there is no particular limitation, but a dry electrode containing a fibrillar resin such as polytetrafluoroethylene resin (PTFE) as a binder resin is preferred, as in the secondary battery electrode described in JP 2022-103141 A. Also preferred is a dry electrode containing coated negative electrode active material particles for lithium ion batteries and a conductive filler, as in the lithium ion battery negative electrode described in JP 2023-163593 A.

[0046] <Secondary Battery> The secondary battery of the present invention includes the secondary battery electrode of the present invention, and has excellent charge / discharge efficiency (coulomb efficiency) because the electrolyte solution is sufficiently permeated into the electrode.

[0047] Examples of secondary batteries include lithium ion batteries and sodium ion batteries.

[0048] 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 for the current collector, electrolyte, separator, etc. As the electrolyte, it is preferable to use ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), propylene carbonate (PC), or a mixture thereof as a non-aqueous solvent. As the electrolyte contained in the electrolyte, electrolytes used in known electrolytes can be used. For example, lithium salts can be used in the case of lithium ion batteries, and sodium salts can be used in the case of sodium ion batteries.

[0049] The lithium salt is LiPF ６ , LiBF ４ , LiSbF ６ , LiAsF ６, LiClO ４ and LiN(FSO ２ ) ２ Lithium salts of inorganic anions such as LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ and LiC(CF ３ SO ２ ) ３ Among these, LiPF ６ (lithium hexafluorophosphate), LiFSI (lithium bis(fluorosulfonyl)imide), etc. can be preferably used.

[0050] Examples of sodium salts include NaPF ６ , NaBF ４ , NaClO ４ and NaAsF ６ inorganic sodium salts such as; and NaCF ３ SO ３ , NaN(CF ３ SO ２ ) ２ , NaN(C ２ F ５ SO ２ ) ２ , NaN(FSO ２ ) ２ , NaC(CF ３ SO ２ ) ３ Among these, preferred from the viewpoint of battery output and charge / discharge cycle characteristics is NaPF ６ is.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The present specification discloses the following:

[0055] The present disclosure (I) is an electrode composition for a secondary battery containing an electrode active material, a binder resin, and an additive, wherein the additive contains a compound (A) represented by the following general formula (1), and the additive has a hydroxyl value of 30 KOH mg / g or less. １ -O-(AO) ｍ -R ２ (1) [In the formula, AO is an alkyleneoxy group having 2 to 4 carbon atoms, m is a number of 3 to 20 representing the average number of repetitions of the alkyleneoxy group, and (AO) ｍ is a polyoxyalkylene chain, the polyoxyalkylene chain contains ethyleneoxy groups, and the molar ratio of the ethyleneoxy groups in the polyoxyalkylene chain is 90% or more based on the total number of moles of the alkyleneoxy groups. １ is an alkyl group having 1 to 20 carbon atoms, and R ２ is an alkyl group having 1 to 2 carbon atoms.

[0056] The present disclosure (II) is １ is an alkyl group having 1 to 13 carbon atoms.

[0057] The present disclosure (III) is the electrode composition for a secondary battery according to the present disclosure (I) or (II), in which the hydroxyl value of the additive is 20 KOHmg / g or less.

[0058] The present disclosure (IV) is the electrode composition for a secondary battery according to any one of the present disclosures (I) to (III), in which the content of the additive is 0.01 to 2 wt % based on the weight of the electrode active material.

[0059] The present disclosure (V) 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 (I) to (IV).

[0060] The present disclosure (VI) is a secondary battery including the electrode for a secondary battery according to the present disclosure (V).

[0061] 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.

[0062] (Preparation of Additives 1 to 26) The following additives 1 to 26 were prepared. For each additive, R in the general formula (1) of the compound (A) contained １ , R ２ and the average repeat number m of the alkyleneoxy group (AO) and the polyoxyalkylene chain [(AO) ｍ The molar ratio of ethyleneoxy groups in the copolymer and the hydroxyl value of the additive are shown in Table 1.

[0063] (Production Example 1: Production of Additive 1) Ethylene oxide (EO) was added to methanol to produce an EO 8.6 mole adduct of methanol. Next, 413 parts of the EO 8.6 mole adduct of methanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and nitrogen substitution was performed at 30°C. The vessel was then reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After the reaction was completed, 220 parts of ion-exchanged water was added to the resulting reaction product, and the mixture was stirred at 20°C for 1 hour to dissolve excess alkali and the resulting salt. After allowing to stand, the lower layer was discarded using a separatory funnel, and Kyoward 600 (manufactured by Kyowa Chemical Industry Co., Ltd.) was added in an amount of 1% by weight of the recovered upper layer. After stirring, the Kyoward 600 was removed by suction filtration, thereby obtaining the R １ is a methyl group, R ２ Additive 1 containing compound (A-1) in which is a methyl group and m is 8.6 was obtained. The content of compound (A-1) in Additive 1 was 99.1%. The hydroxyl value of Additive 1 was 1.2 KOHmg / g.

[0064] (Production Example 2: Production of Additive 2) Ethylene oxide (EO) was added to methanol to produce an EO 3 mole adduct of methanol. Next, 165 parts of the EO 3 mole adduct of methanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R in general formula (1). １ is a methyl group, R ２ Additive 2 containing compound (A-2) in which is a methyl group and m is 3 was obtained. The content of compound (A-2) in Additive 2 was 99.3%. The hydroxyl value of Additive 2 was 2.4 KOHmg / g.

[0065] (Production Example 3: Production of Additive 3) Ethylene oxide (EO) was added to 1-hexanol to produce an EO 5 mole adduct of 1-hexanol. Next, 323 parts of the EO 5 mole adduct of 1-hexanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for a further 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain a compound represented by R １ is a hexyl group, R ２ Additive 3 containing compound (A-3) in which is a methyl group and m is 5 was obtained. The content of compound (A-3) in Additive 3 was 98.6%. The hydroxyl value of Additive 3 was 2.4 KOHmg / g.

[0066] (Production Example 4: Production of Additive 4) Ethylene oxide (EO) was added to isodecyl alcohol to produce an EO 7 mole adduct of isodecyl alcohol. Next, 464 parts of the EO 7 mole adduct of isodecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain an adduct of R １ is an isodecyl group, R ２ Additive 4 was obtained containing compound (A-4) in which is a methyl group and m is 7. The content of compound (A-4) in Additive 4 was 99.0%. The hydroxyl value of Additive 4 was 1.2 KOHmg / g.

[0067] (Production Example 5: Production of Additive 5) Ethylene oxide (EO) was added to isodecyl alcohol to produce an EO 7 mole adduct of isodecyl alcohol. Next, 478 parts of the EO 7 mole adduct of isodecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 78 parts of ethyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain an adduct of R １ is an isodecyl group, R ２ Additive 5 containing compound (A-5) in which is an ethyl group and m is 7 was obtained. The content of compound (A-5) in Additive 5 was 97.8%. The hydroxyl value of Additive 5 was 2.6 KOHmg / g.

[0068] (Production Example 6: Production of Additive 6) Ethylene oxide (EO) was added to tridecyl alcohol to produce an EO 10 mole adduct of tridecyl alcohol. Next, 638 parts of the EO 10 mole adduct of tridecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain a compound represented by R in general formula (1). １ is a tridecyl group, R ２ Additive 6 containing compound (A-6) in which is a methyl group and m is 10 was obtained. The content of compound (A-6) in Additive 6 was 98.5%. The hydroxyl value of Additive 6 was 1.3 KOHmg / g.

[0069] (Production Example 7: Production of Additive 7) Ethylene oxide (EO) was added to pentadecyl alcohol to produce an EO 17 mole adduct of pentadecyl alcohol. Next, 974 parts of the EO 17 mole adduct of pentadecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 78 parts of ethyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain a compound represented by R in general formula (1). １ is a pentadecyl group, R ２ Additive 7 was obtained containing compound (A-7) in which is an ethyl group and m is 17. The content of compound (A-7) in Additive 7 was 98.0%. The hydroxyl value of Additive 7 was 1.1 KOHmg / g.

[0070] (Production Example 8: Production of Additive 8) Ethylene oxide (EO) was added to isostearyl alcohol to produce an EO 20 mole adduct of isostearyl alcohol. Next, 1,148 parts of the EO 20 mole adduct of isostearyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and nitrogen substitution was carried out at 30°C. Thereafter, the vessel was placed in a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining a temperature not exceeding 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R in general formula (1). １ is an isostearyl group, R ２ Additive 8 containing compound (A-8) in which is a methyl group and m is 20 was obtained. The content of compound (A-8) in Additive 8 was 98.8%. The hydroxyl value of Additive 8 was 0.6 KOHmg / g.

[0071] (Production Example 9: Production of Additive 9) Ethylene oxide (EO) was added to isodecyl alcohol to produce an EO 7 mole adduct of isodecyl alcohol. Next, 464 parts of the EO 7 mole adduct of isodecyl alcohol and 40 parts of sodium hydroxide were charged into a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 47 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was allowed to proceed for an additional 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain Additive 9 containing the above compound (A-4). The content of compound (A-4) in Additive 9 was 78.2%. The hydroxyl value of Additive 9 was 26.2 KOHmg / g. Additive 9 was obtained by adding 47 parts of methyl chloride to the R ２ is a hydroxyl group in a larger amount than Additive 4.

[0072] (Production Example 10: Production of Additive 10) Ethylene oxide (EO) was added to isostearyl alcohol to produce an EO 20 mole adduct of isostearyl alcohol. Next, 1,148 parts of the EO 20 mole adduct of isostearyl alcohol and 40 parts of sodium hydroxide were charged into a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and nitrogen substitution was performed at 30°C. Thereafter, the vessel was reduced in pressure, and 34 parts of methyl chloride were added dropwise while maintaining a temperature not exceeding 50°C. After the dropwise addition, the reaction was allowed to proceed for an additional 8 hours. After completion of the reaction, the same operation as in Production Example 1 was performed to obtain Additive 10 containing the above-mentioned Compound (A-8). The content of Compound (A-8) in Additive 10 was 55.6%. The hydroxyl value of Additive 10 was 21.6 KOHmg / g. Additive 10 was obtained by adding the R ２ is a hydroxyl group in a larger amount than Additive 8.

[0073] (Production Example 11: Production of Additive 11) Ethylene oxide (EO) was added to propanol to produce Additive 11 containing a compound (comparison A-1) which is an EO 5 mole adduct of propanol. The hydroxyl value of Additive 11 was 200 KOHmg / g.

[0074] (Production Example 12: Production of Additive 12) Ethylene oxide (EO) was added to hexanol to produce Additive 12 containing a compound (comparison A-2) that is an EO 5 mole adduct of hexanol. The hydroxyl value of Additive 12 was 174 KOHmg / g.

[0075] (Production Example 13: Production of Additive 13) Ethylene oxide (EO) was added to isodecyl alcohol to produce Additive 13 containing a compound (comparison A-3) that is an EO 7 mole adduct of isodecyl alcohol. The hydroxyl value of Additive 13 was 120 KOHmg / g.

[0076] (Production Example 14: Production of Additive 14) Ethylene oxide (EO) was added to propanol to produce an EO 10 mole adduct of propyl alcohol. Next, 526 parts of the EO 10 mole adduct of propanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 95 parts of propyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain an adduct of R １ is a propyl group, R ２ Additive 14 was obtained, containing a compound (comparison A-4) in which is a propyl group and m is 10. The hydroxyl value of Additive 14 was 0.8 KOHmg / g.

[0077] (Production Example 15: Production of Additive 15) Ethylene oxide (EO) was added to 1-tetracosanol to produce an EO 6 mole adduct of 1-tetracosanol. Next, 616 parts of the EO 6 mole adduct of 1-tetracosanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for a further 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R １ is a tetracosyl group, R ２ Additive 15 was obtained, containing a compound (comparison A-5) in which is a methyl group and m is 6. The hydroxyl value of Additive 15 was 1.6 KOHmg / g.

[0078] (Production Example 16: Production of Additive 16) Ethylene oxide (EO) was added to isodecyl alcohol to produce an EO 7 mole adduct of isodecyl alcohol. Next, 520 parts of the EO 7 mole adduct of isodecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 130 parts of pentyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain an isodecyl alcohol-EO 7 mole adduct of R in general formula (1). １ is an isodecyl group, R ２ Additive 16 was obtained, containing a compound (comparison A-6) in which is a pentyl group and m is 7. The hydroxyl value of Additive 16 was 1.8 KOHmg / g.

[0079] (Production Example 17: Production of Additive 17) Ethylene oxide (EO) was added to propanol to produce an EO 25 mole adduct of propanol. Next, 1,158 parts of the EO 25 mole adduct of propanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R in general formula (1). １ is a propyl group, R ２ Additive 17 was obtained, containing a compound (comparison A-7) in which is a methyl group and m is 25. The hydroxyl value of Additive 17 was 1.0 KOHmg / g.

[0080] (Production Example 18: Production of Additive 18) Ethylene oxide (EO) was added to propanol to produce an EO 1 mole adduct of propanol. Next, 102 parts of the EO 1 mole adduct of propanol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After the reaction was completed, the same operation as in Production Example 1 was carried out to obtain a compound represented by R １ is a propyl group, R ２ Additive 18 was obtained, containing a compound (comparison A-8) in which is a methyl group and m is 1. The hydroxyl value of Additive 18 was 5.3 KOHmg / g.

[0081] (Production Example 19: Production of Additive 19) Ethylene oxide (EO) was added to stearyl alcohol to produce Additive 19 containing a compound (comparison A-9) which is an EO 100 mole adduct of stearyl alcohol. The hydroxyl value of Additive 19 was 12.1 KOHmg / g.

[0082] (Production Example 20: Production of Additive 20) Ethylene oxide (EO) was added to stearyl alcohol to produce Additive 20 containing a compound (comparison A-10) which is an EO 20 mole adduct of stearyl alcohol. The hydroxyl value of Additive 20 was 49.0 KOHmg / g.

[0083] (Production Example 21: Production of Additive 21) 4543 parts of Additive 19 (comparison A-9) and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R １ is a stearyl group, R ２ Additive 21 containing a compound (comparison A-11) in which is a methyl group and m is 100 was obtained. The hydroxyl value of Additive 21 was 2.4 KOHmg / g.

[0084] (Production Example 22: Production of Additive 22) 1,114 parts of Additive 20 (comparison A-10) and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was allowed to proceed for a further 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R １ is a stearyl group, R ２ Additive 22 containing compound (A-9) in which is a methyl group and m is 20 was obtained. The content of compound (A-9) in Additive 22 was 98.3%. The hydroxyl value of Additive 22 was 0.8 KOHmg / g.

[0085] (Production Example 23: Production of Additive 23) Ethylene oxide (EO) and propylene oxide (PO) were added to isodecyl alcohol at a molar ratio of EO / PO = 11 / 1 to produce Additive 23 containing a compound (ratio A-12) that was an adduct of 12 moles of AO (11 moles of EO / 1 mole of PO) of isodecyl alcohol. The hydroxyl value of Additive 23 was 78.5 KOHmg / g.

[0086] (Production Example 24: Production of Additive 24) 677 parts of Additive 23 (comparison A-12) and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was put into a reduced pressure state, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R １ is an isodecyl group, R ２ Additive 24 containing compound (A-10) in which is a methyl group and m is 12 was obtained. The content of compound (A-10) in Additive 24 was 98.5%. The hydroxyl value of Additive 24 was 1.2 KOHmg / g.

[0087] (Production Example 25: Production of Additive 25) Ethylene oxide (EO) and propylene oxide (PO) were added to isodecyl alcohol in a molar ratio of EO / PO = 13 / 2 to produce an adduct of isodecyl alcohol with 15 moles of AO (13 moles of EO / 2 moles of PO). 819 parts of the adduct of isodecyl alcohol with 15 moles of AO (13 moles of EO / 2 moles of PO) and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain the compound represented by R in general formula (1). １ is an isodecyl group, R ２ Additive 25 was obtained, containing a compound (comparison A-13) in which is a methyl group and m is 15. The hydroxyl value of Additive 25 was 1.2 KOHmg / g.

[0088] (Production Example 26: Production of Additive 26) Propylene oxide (PO) was added to isodecyl alcohol to produce a 7-mol PO adduct of isodecyl alcohol. Next, 464 parts of the 7-mol PO adduct of isodecyl alcohol and 40 parts of sodium hydroxide were placed in a pressure-resistant reaction vessel equipped with a thermometer, a stirrer, a heating / cooling device, and a dropping bomb, and the atmosphere was replaced with nitrogen at 30°C. Thereafter, the vessel was reduced in pressure, and 60 parts of methyl chloride were added dropwise while maintaining the temperature below 50°C. After the dropwise addition, the reaction was continued for another 8 hours. After completion of the reaction, the same operation as in Production Example 1 was carried out to obtain a compound represented by R in general formula (1). １ is an isodecyl group, R ２ Additive 26 was obtained, containing a compound (comparison A-14) in which is a methyl group and m is 7. The hydroxyl value of Additive 26 was 2.1 KOHmg / g.

[0089]

[0090] (Production Examples 27 to 36: Production of Additives 27 to 36) In Production Examples 27, 29, 30, and 34, Additive 4 and Additive 13 were mixed in the weight ratios shown in Table 2 to produce Additives 27, 29, 30, and 34. In Production Examples 28 and 33, Additive 3 and Additive 12 were mixed in the weight ratios shown in Table 2 to produce Additives 28 and 33. In Production Examples 31 and 35, Additive 4 and Additive 26 were mixed in the weight ratios shown in Table 2 to produce Additives 31 and 35. In Production Examples 32 and 36, Additive 5 and Additive 26 were mixed in the weight ratios shown in Table 2 to produce Additives 32 and 36.

[0091]

[0092] <Evaluation of Potential Withstanding Properties of Additives: Measurement of Cyclic Voltammetry (CV)> Each additive was added to a commercially available electrolyte solution to prepare an electrolyte solution for evaluating potential withstanding properties, and the potential withstanding properties of each additive were evaluated. (Preparation of Electrolyte Solution for Potential Withstanding Properties) LBG electrolyte solution ["LBG-96533", manufactured by Kishida Chemical Co., Ltd., solvent: mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio of EC:DEC = 1:1), electrolyte: LiPF ６ Additives 1 to 36 were dissolved in a 10% concentration of LiPF (concentration 1 mol / L) to prepare electrolyte solutions for evaluating potential resistance. LBG electrolyte solution containing no additives was used as a comparative electrolyte. ６ indicates lithium hexafluorophosphate.

[0093] (Preparation of Cell for Evaluating Potential Withstanding Properties) A ​​2032-type coin cell spacer [material: SUS316, manufactured by Hosen Co., Ltd.] as a working electrode, a separator [product name "#3501", manufactured by Celgard Inc.], and a lithium metal foil [manufactured by Honjo Metals Co., Ltd.] as a reference electrode were stacked in this order, and 30 μL of the above-mentioned electrolyte for evaluating potential withstanding properties was injected into the cell to prepare a coin cell for evaluating potential withstanding properties.

[0094] The prepared evaluation cell was used in the potential range of 0 to 4.5 V (vs. Li / Li ＋), cyclic voltammetry measurements were performed at a potential sweep rate of 10 mV / s to examine current changes. When a decomposition reaction of the additive occurs, the current value observed in the above potential range increases. To determine the amount of additive decomposition, the relative current value relative to a comparative electrolyte solution containing no additive was calculated using the following formula. The closer this value is to 1, the less the amount of additive decomposition, i.e., the higher the additive's potential resistance. Furthermore, it is believed that repeated charge and discharge in an electrode obtained from an electrode composition containing the additive and a battery equipped with the electrode are less likely to experience a decrease in battery performance. The relative current value calculated using the following formula and evaluation according to the following evaluation criteria are shown in Tables 1 and 2. (Relative current value) = (current value flowing at 0.7 V in CV measurement of evaluation cells containing each of additives 1 to 36) ÷ (current value flowing at 0.7 V in CV measurement of comparative electrolyte containing no additive) [Evaluation criteria] ◎: Relative current value is 0.94 or more and 1.06 or less ○: Relative current value is more than 1.06 and 1.12 or less, or 0.88 or more and less than 0.94 △: Relative current value is more than 1.12 and 1.20 or less, or 0.80 or more and less than 0.88 ×: Relative current value is more than 1.20 or less than 0.80

[0095] (Preparation of Electrode Active Materials) The following electrode active materials were prepared. Graphite: artificial graphite (FSN-1, manufactured by Shanshan China Co., Ltd., 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) NCA: LiNi ０．８ Co ０．１５ Al ０．０５ O ２ ("HED NCA 7050", manufactured by BASF Toda Battery Materials LLC, volume average particle size (Dv50) 6.6 μm) NaCrO ２ : Sodium chromite (manufactured by Kojundo Chemical Laboratory)

[0096] (Preparation of binder resin and thickener) The following binder resin and thickener were prepared. SBR: styrene-butadiene rubber (BM451B, manufactured by Zeon Corporation) CMC: carboxymethyl cellulose (CMC2260, manufactured by Daicel Corporation) PTFE: polytetrafluoroethylene (Polyflon PTFE F-104, manufactured by Daikin Industries, Ltd.) PVDF: polyvinylidene fluoride (#9300, manufactured by Kishida Chemical Co., Ltd.)

[0097] (Examples 1 to 18, Comparative Examples 1 to 19: Preparation of Lithium-Ion Battery Electrode Compositions (Negative Electrode Compositions) and Electrodes (Negative Electrodes)) 95.0 parts of graphite as the electrode active material and 1.5 parts of CMC as a thickener were stirred using a spatula, and then a mixture was obtained by stirring three times for two minutes at 2000 rpm using a planetary stirring mixer kneader (Awatori Rentaro [manufactured by Thinky Corporation]). To this mixture were added 3.0 parts of water and each of the additives in the amounts shown in Table 3 or Table 4, and the mixture was stirred for two minutes at 2000 rpm using the Awatori Rentaro. In Comparative Example 1, no additives were added, and the amount of graphite was 96.0 parts. 2.0 parts of water was then added, and the mixture was stirred for two minutes at 2000 rpm using the Awatori Rentaro. Further, 2.5 parts of SBR was added as a binder resin, and the mixture was stirred at 1000 rpm for 1 minute using a mixer to prepare an electrode composition (negative electrode composition). Each of the obtained electrode compositions was applied to one side of a current collector (copper foil) using a wire bar in the atmosphere so that the active material weight was 7.5 to 8.5 mg / cm. ２ The electrode layer was formed on the current collector by applying the solution to the electrode sheet so that the thickness of the electrode sheet was 16 mm and drying the electrode sheet in a circulating air dryer at 80°C for 10 minutes. (Hereinafter, the current collector and electrode layer will be collectively referred to as the electrode sheet.) Nine pieces of 16 mm diameter were punched out from the center of the obtained electrode sheet, and three of the nine pieces were further dried under reduced pressure (1.3 kPa) at 80°C for 30 minutes, and then pressed with a roll press (manufactured by Tester Sangyo Co., Ltd.) to the target electrode density (electrode thickness) to prepare an electrode (negative electrode) for evaluating electrolyte permeability. The remaining six pieces were dried under reduced pressure (1.3 kPa) at 80°C for 2 hours, and then pressed with a roll press to the target electrode density of 1.5 g / cm. ３The 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 to an electrode density of 1.5 g / cm. ３ The electrode (negative electrode) for the peel test was prepared by pressing the electrode so that the thickness of the electrode was 1 / 4.

[0098] <Peel Test (Evaluation of Adhesion Strength Between Current Collector and Electrode (Electrode Layer))> Double-sided tape (Nichiban Nicetack: Model No. NW-K15) was applied to the electrode composition surface of the peel test electrode prepared above, and the electrode composition surface was attached to a SUS plate (thickness 1.2 mm) so that it faced each other to form a test specimen. The metal foil (copper foil) at one end of the test specimen was peeled from the SUS plate, and an interfacial fracture test was performed in which the SUS plate side was gripped with the chuck of the lower test jig of a bench-top precision universal testing machine (Autograph AGS-X, manufactured by Shimadzu Corporation) and the metal foil was gripped with the chuck of the upper jig to peel the electrode composition from the current collector. A 20 N test jig was used, and the tensile speed was 150 mm / min. The obtained measurement results were read in accordance with JIS K 6854-2:1999, and the average peel force (N) was determined. The average peel force was divided by the width (0.025 m) of the test piece and recorded as the electrode peel strength (N / m) in Tables 3 and 4. The larger the electrode peel strength (N / m), the higher the adhesive strength between the current collector and the electrode (electrode layer).

[0099] <Calculation of electrode density> The weight of the electrode for evaluating electrolyte permeability, which was pressed to the target electrode density (electrode thickness) using a roll press (manufactured by Tester Sangyo Co., Ltd.), and the weight and thickness of the current collector (copper foil) were measured, and the electrode density (g / cm) was calculated using the following formula. ３ ) = (electrode weight for electrolyte permeability evaluation (g) - current collector weight (μg) x 10 －３ ) / (0.8 ２ × 3.14 × ((electrode thickness for evaluating electrolyte permeability (μm) − current collector thickness (μm)) × 10 －４ ))

[0100] <Evaluation of Electrolyte Permeability (Electrolyte Permeation Time) of Electrodes for Lithium Ion Batteries> The electrodes for evaluating electrolyte permeability prepared above were placed in a sealed container, and 10 μL of electrolyte was dropped onto the electrode. The time (minutes) until the electrolyte permeated the electrode was measured. A shorter permeation time indicates better permeability. The measurement results are shown in Tables 3 and 4. For each example and comparative example, the electrolyte permeation time of three electrodes was measured in units of one second, and the arithmetic mean value was taken as the electrolyte permeation time (minutes). The electrolyte used was the same LBG electrolyte used in the evaluation of potential resistance ["LBG-96533", manufactured by Kishida Chemical Co., Ltd., solvent: mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio of EC:DEC = 1:1), electrolyte: LiPF ６ (concentration 1 mol / L)] was used.

[0101] (Preparation of Lithium-Ion Battery (Negative Electrode Half Cell) for Charge / Discharge Test) A lithium metal foil (manufactured by Honjo Metals Co., Ltd.), a separator (product name "#3501" manufactured by Celgard Inc.), and the battery evaluation electrodes (negative electrodes) prepared in Examples 1 to 18 and Comparative Examples 1 to 19 were stacked in this order, and an electrolyte was injected to prepare a battery (2032-type coin cell) for charge / discharge test.

[0102] <Charge / Discharge Test: Measurement of Initial Coulombic Efficiency> The initial coulombic efficiency of the charge / discharge test battery 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 0.0 V at a current of 0.05 C using a constant current charging method (CC mode), and after a 10-minute break, discharged to 1.5 V at a current of 0.05 C. The charged capacity was defined as [initial charge capacity (mAh)], and the discharged capacity was defined as [initial discharge capacity (mAh)]. The initial coulombic efficiency was calculated using the following formula, and the results are shown in Tables 3 and 4. For each example and comparative example, measurements were performed on three batteries, and the initial coulombic efficiency (%) was calculated, and the arithmetic average value was used as the analytical value. [Initial coulombic efficiency (%)] = [initial discharge capacity] ÷ [initial charge capacity] × 100

[0103] <Charge-Discharge Test: Measurement of Capacity Retention Rate After Severe Test> The capacity retention rate of the charge-discharge test battery 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 0 V at a current of 0.05 C using a constant current charging method (also referred to as CC mode), and after a 10-minute pause, was discharged to 1.5 V at a current of 0.05 C. The discharged capacity at this time was designated as [1-Cycle Discharge Capacity (mAh)]. The battery was again charged and discharged under the same conditions, and the discharged capacity at this time was designated as [2-Cycle Discharge Capacity (mAh)]. Next, the battery was charged to 0 V at a current of 0.1 C, and after a 10-minute pause, was discharged to 1.5 V at a current of 0.1 C. The discharged capacity at this time was designated as [3-Cycle Discharge Capacity (mAh)]. Furthermore, the battery was charged to 0 V at a current of 0.5 C, and after a 10-minute pause, discharged to 1.5 V at a current of 0.1 C. 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 pause, 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 was calculated using the following formula, and the results are shown in Tables 3 and 4. For each example and comparative example, the test capacity retention rate (%) was calculated for three batteries, and the arithmetic average was defined as the analytical value. Capacity retention rate (%) after severe test = [5-cycle discharge capacity (mAh)] / [2-cycle discharge capacity (mAh)]

[0104]

[0105]

[0106] (Examples 19 to 23, Comparative Examples 20 to 22: Preparation of Sodium-Ion Battery Electrode Composition (Negative Electrode Composition) and Electrode (Negative Electrode)) 1.5 parts of acetylene black (AB: "Denka Black Li100", manufactured by Denka Co., Ltd., average primary particle size: 35 nm) as a conductive additive, 1.5 parts of carboxymethyl cellulose (CMC) as a thickener, and 40.0 parts of ion-exchanged water were stirred at 2000 rpm for 5 minutes using a planetary stirring mixer (Awatori Rentaro [manufactured by Thinky Corporation]). Next, 1.5 parts of styrene-butadiene rubber (SBR) as a binder resin was added, and the mixture was stirred using the Awatori Rentaro at 2000 rpm for 5 minutes. To the resulting dispersion, hard carbon (HC) in the amounts shown in Table 5 as the negative electrode active material, 0.5 parts of each additive, and 60.0 parts of ion-exchanged water were added, and the mixture was stirred for 5 minutes at 2000 rpm using a mixer to prepare a negative electrode composition slurry. In Comparative Example 20, no additive was added and 95.5 parts of hard carbon was used. Each of the resulting electrode compositions was applied to one side of a current collector (copper foil) in the atmosphere using a wire bar so that the active material weight was 7.5 to 8.5 mg / cm. ２ The electrode layer was formed on the current collector by applying the solution to the electrode sheet so that the thickness of the electrode sheet was 16 mm and drying the electrode sheet in a circulating air dryer at 80°C for 10 minutes. (Hereinafter, the current collector and electrode layer will be collectively referred to as the electrode sheet.) Nine pieces of 16 mm diameter were punched out from the center of the obtained electrode sheet, and three of the nine pieces were further dried under reduced pressure (1.3 kPa) at 80°C for 30 minutes, and then pressed with a roll press (manufactured by Tester Sangyo Co., Ltd.) to the target electrode density (electrode thickness) to prepare an electrode (negative electrode) for evaluating electrolyte permeability. The remaining six pieces were dried under reduced pressure (1.3 kPa) at 80°C for 2 hours, and then pressed with a roll press to the target electrode density of 1.2 g / cm. ３ 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 to an electrode density of 1.2 g / cm. ３ The electrode (negative electrode) for the peel test was prepared by pressing the electrode so that the thickness of the electrode was 1 / 4.

[0107] <Electrode Evaluation> A peel test was performed on the prepared electrode for peel test using the electrode composition for lithium ion batteries (negative electrode composition) to measure the electrode peel strength. The electrode density of the electrode for evaluating electrolyte permeability was also calculated using the same method as that for the electrode for evaluating electrolyte permeability using the electrode composition for lithium ion batteries (negative electrode composition). Regarding electrolyte permeability, a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio EC:DEC = 1:1) was used as the electrolyte, and NaPF ６ The electrolyte permeability of the lithium-ion battery electrode was evaluated in the same manner as in the evaluation of the electrolyte permeability of the lithium-ion battery electrode, except that a solution containing 1 mol / L of sodium ion battery electrolyte (hereinafter also referred to as the sodium ion battery electrolyte) was used. The evaluation results are shown in Table 5.

[0108] (Preparation of Sodium-Ion Batteries (Negative Electrode Half-Cells) for Charge / Discharge Tests) Half-cells for charge / discharge tests were prepared using the battery evaluation electrodes (negative electrodes) prepared in Examples 19 to 23 and Comparative Examples 20 to 22 as negative electrodes. Starting from the positive electrode side, carbon-coated aluminum foil as a positive electrode current collector, sodium metal foil (manufactured by Kanto Chemical Co., Ltd.) as a counter electrode (positive electrode), a separator (product name "#3501" manufactured by Celgard Corporation), and the above battery evaluation electrode (negative electrode) were stacked in this order, and a sodium-ion battery electrolyte was poured into them. Then, copper foil was placed on top of the negative electrode current collector, and the sodium-ion battery electrolyte was poured into them. The resulting stack was then vacuum-laminated to prevent oxygen from entering, thereby preparing batteries for charge / discharge tests. Three batteries for charge / discharge tests were prepared for each Example and Comparative Example.

[0109] <Battery Evaluation> The initial coulombic efficiency and the capacity retention rate after the severe test were measured using the same method as the charge-discharge test method for the lithium ion battery for charge-discharge test (negative electrode half cell). The evaluation results are shown in Table 5.

[0110]

[0111] (Examples 24 to 28, Comparative Examples 23 to 25: Preparation of dry electrodes (dry positive electrodes) for lithium ion batteries) 92.57 parts of NCA as a positive electrode active material, 1.49 parts of acetylene black [manufactured by Denka Co., Ltd., "Denka Black Li100"] as a conductive additive, and 4.95 parts of PTFE (manufactured by Daikin Industries, Ltd., "Polyflon PTFE F-104") as a binder resin were weighed and pre-mixed at room temperature with a universal mixer high-speed mixer FS25 [manufactured by Earth Technica Co., Ltd.] (50 rpm, 15 minutes), and then mixed with a high-speed mixer (500 rpm, 1 minute). Subsequently, 0.99 parts of additive were added, and further mixed with a universal mixer high-speed mixer FS25 (5000 rpm, 3 minutes, 80 ° C.) to obtain a positive electrode composition. The positive electrode composition obtained above was formed into a bulk shape (approximately 1.5 mm thick) and rolled into a sheet to obtain a rolled sheet. The rolling was performed at 80°C. The rolled sheet obtained above was then folded in half to crush it, and then re-formed into a bulk shape. This process was repeated four times to promote fibrillation by rolling it into a sheet using a metal roll on a flat plate. This was then further rolled to obtain a dry positive electrode sheet with a thickness of 500 μm. The dry positive electrode sheet was then cut out and placed in a press for rolling. A load of 5 kN was then repeatedly applied to adjust the thickness, thereby obtaining a dry electrode. The gap was adjusted so that the final electrode thickness was approximately 200 μm. The electrode thickness of each obtained electrode (positive electrode) was measured using a film thickness meter (manufactured by Mitutoyo) and is shown in Table 6. The electrode thickness was calculated as the average of the thicknesses measured at three random locations. In the dry electrodes, the electrode thickness was made uniform in each Example and Comparative Example so that the evaluation of electrolyte permeability could be performed under fair conditions. Comparative Example 23 was a positive electrode composition and electrode (dry positive electrode) containing no additives, and the contents of the electrode active material, binder resin, and conductive additive were as shown in Table 6.

[0112] <Evaluation of electrolyte permeability (electrolyte permeation time) of dry electrodes for lithium ion batteries> Areas of the dry electrodes produced in Examples 24 to 28 and Comparative Examples 23 to 25 where the thickness variation was within 5% were sampled in 25 mm squares to prepare dry electrodes for permeability evaluation. The electrolyte permeability was evaluated using the same evaluation method and criteria as for the slurry electrodes, except that these dry electrodes for permeability evaluation were used as test pieces. The results are shown in Table 6.

[0113] <Preparation of Lithium-Ion Batteries (Dry Positive Electrode Half-Cells) for Charge / Discharge Tests> Half-cells for charge / discharge tests were prepared using the dry electrodes (cathode) prepared in Examples 24-28 and Comparative Examples 23-25. Starting from the positive electrode side, carbon-coated aluminum foil was used as the positive electrode current collector, the dry electrode (cathode), a separator [product name "#3501" manufactured by Celgard Corporation], lithium metal foil [manufactured by Honjo Metals Co., Ltd.] was used as the counter electrode (negative electrode), and copper foil was used as the negative electrode current collector. The same LBG electrolyte solution used in the potential resistance evaluation was used as the electrolyte. After injecting the electrolyte, the cells were vacuum-laminated to prevent oxygen from entering, and batteries for charge / discharge tests were prepared. Three batteries for charge / discharge tests were prepared for each Example and Comparative Example.

[0114] <Charge / Discharge Test: Measurement of Initial Coulombic Efficiency (Half Cells for Charge / Discharge Tests Using the Dry Electrodes Prepared in Examples 24-28 and Comparative Examples 23-25 ​​as the Positive Electrode)> The initial coulombic efficiency of the charge / discharge test batteries prepared above was evaluated using a charge / discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation] at 25°C. The batteries were charged to 4.2 V at a current of 0.05 C using a constant current / constant voltage charging method (also referred to as CCCV mode), and then charged while maintaining 4.2 V until the current reached 0.0025 C. After a 10-minute pause, the batteries were discharged to 2.5 V at a current of 0.05 C. The charge capacity at this time was designated as [initial charge capacity (mAh)], and the discharge capacity was designated as [initial discharge capacity (mAh)]. The initial coulombic efficiency was calculated using the following formula, and the results are shown in Table 6. For each example and comparative example, measurements were performed on three batteries, the initial coulombic efficiency (%) was calculated, and the arithmetic mean value was used as the analytical value: [Initial coulombic efficiency (%)] = [Initial discharge capacity] ÷ [Initial charge capacity] × 100

[0115] <Charge-Discharge Test: Measurement of Capacity Retention Rate After Severe Test (Half-Cells for Charge-Discharge Tests Using the Dry Electrodes Prepared in Examples 24-28 and Comparative Examples 23-25 ​​as the Positive Electrodes)> The capacity retention rate of the charge-discharge test batteries was evaluated at 25°C using a charge-discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation] according to the following method. The batteries were charged to 4.2 V at a current of 0.05 C using a constant current charging method (also referred to as CC mode), rested for 10 minutes, and then discharged to 2.5 V at a current of 0.05 C. The discharged capacity at this time was designated as [1-Cycle Discharge Capacity (mAh)]. Charge-discharge was then performed again under the same conditions, and the discharged capacity at this time was designated as [2-Cycle Discharge Capacity (mAh)]. Next, the batteries were charged to 4.2 V at a current of 0.1 C, rested for 10 minutes, and then discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was defined as [3-cycle discharge capacity (mAh)]. Furthermore, the battery was charged to 4.2 V at a current of 0.5 C, and after a 10-minute pause, discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was defined as [4-cycle discharge capacity (mAh)]. Finally, the battery was charged to 4.2 V at a current of 1.0 C, and after a 10-minute pause, discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was defined as [5-cycle discharge capacity (mAh)]. The post-stress test capacity retention rate (%) was calculated using the following formula, and the results are shown in Table 6. For each example and comparative example, the test capacity retention rate (%) was calculated for three batteries, and the arithmetic average was used as the analytical value. Post-stress test capacity retention rate (%) = [5-cycle discharge capacity (mAh)] / [2-cycle discharge capacity (mAh)]

[0116]

[0117] (Examples 29 to 33, Comparative Examples 26 to 28: Preparation of electrode compositions (positive electrode compositions) and electrodes (positive electrodes) for lithium ion batteries) The positive electrode active material, binder resin, conductive aid, and additives were weighed out according to the parts shown in Table 7, N-methyl-2-pyrrolidone (NMP) was added so that the solids concentration of the composition was 70%, and the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirring mixer (Awatori Rentaro [manufactured by Thinky Corporation]) to prepare positive electrode slurries. Each of the obtained positive electrode slurries was applied in air to one side of a current collector (aluminum foil: 10 μm thick) using a film applicator with a digital film thickness adjustment function so that the active material basis weight was 10 mg / cm. ２ The electrode sheet was then coated with the solution so that the thickness of the electrode was 16 mm, and the coated electrode was dried in a circulating air dryer at 100°C for 20 minutes to form a positive electrode layer on the current collector. (Hereinafter, the current collector and the positive electrode layer will be collectively referred to as the electrode sheet.) Nine pieces of 16 mm diameter were punched out from the center of the obtained electrode sheet, and the sheet was dried in a vacuum dryer at 120°C for 3 hours. The sheet was then pressed twice for 3 seconds at 1.5 MPa in a press to prepare an electrode (positive electrode) for electrolyte permeability and battery evaluation. The electrode sheet was then cut with a cutter to a width of 2.5 cm and a length of 8.0 cm. The sheet was then dried in a vacuum dryer at 120°C for 3 hours. The electrode density was adjusted to 3.2 g / cm using a roll press (manufactured by Tester Sangyo Co., Ltd.). ３ The electrode (positive electrode) for the peel test was prepared by pressing the electrode so as to have a thickness of 100 mm.

[0118] <Electrode Evaluation> A peel test was performed on the prepared electrodes for the peel test using the lithium-ion battery electrode composition (negative electrode composition) to measure the electrode peel strength. The electrode density and electrolyte permeability of the electrodes for the electrolyte permeability evaluation were also calculated using the same method as for the electrodes for the lithium-ion battery electrode composition (negative electrode composition). The evaluation results are shown in Table 7.

[0119] (Preparation of Lithium-Ion Batteries (Positive Electrode Half-Cells) for Charge / Discharge Tests) Half-cells for charge / discharge tests were prepared using the battery evaluation electrodes (positive electrodes) prepared in Examples 29 to 33 and Comparative Examples 26 to 28 as the positive electrodes. Starting from the positive electrode side, carbon-coated aluminum foil as a positive electrode current collector, a battery evaluation electrode (positive electrode), a separator [product name "#3501", manufactured by Celgard Inc.], lithium metal foil as a counter electrode (negative electrode) [manufactured by Honjo Metals Co., Ltd.], and copper foil as a negative electrode current collector were stacked together, and after injecting an electrolyte, the mixture was vacuum-laminated to prevent oxygen from entering, to prepare batteries for charge / discharge tests. Three batteries for charge / discharge tests were prepared for each Example and Comparative Example.

[0120] The charge-discharge tests (measurement of initial coulombic efficiency and measurement of capacity retention rate after severe test) were carried out in the same manner as for the lithium ion battery (dry positive electrode half cell) for the charge-discharge test. The results are shown in Table 7.

[0121]

[0122] (Examples 34 to 38, Comparative Examples 29 to 31: Preparation of Electrode Compositions (Positive Electrode Compositions) and Electrodes (Positive Electrodes) for Sodium Ion Batteries) The positive electrode active material, binder resin, conductive aid, and additives were weighed out according to the parts shown in Table 8, N-methyl-2-pyrrolidone (NMP) was added so that the solids concentration of the composition was 70%, and the mixture was stirred at 2000 rpm for 5 minutes using a planetary stirring mixer (Awatori Rentaro [manufactured by Thinky Corporation]) to prepare positive electrode slurries. Each of the obtained positive electrode slurries was applied in air to one side of a current collector (aluminum foil: 10 μm thick) using a film applicator with a digital film thickness adjustment function so that the active material basis weight was 10 mg / cm. ２The electrode sheet was then coated with the solution so that the thickness of the electrode was 16 mm, and the coated electrode was dried in a circulating air dryer at 100°C for 20 minutes to form a positive electrode layer on the current collector. (Hereinafter, the current collector and the positive electrode layer will be collectively referred to as the electrode sheet.) Nine pieces with a diameter of 16 mm were punched out from the center of the obtained electrode sheet, and the sheet was dried in a vacuum dryer at 120°C for 3 hours. The sheet was then pressed twice for 3 seconds at 1.5 MPa in a press to prepare an electrode (positive electrode) for electrolyte permeability and battery evaluation. The electrode sheet was then cut with a cutter to a width of 2.5 cm and a length of 8.0 cm. The cut pieces were then dried in a vacuum dryer at 120°C for 3 hours and pressed in a roll press (manufactured by Tester Sangyo Co., Ltd.) to an electrode density of 2.5 g / cm. ３ The electrode (positive electrode) for the peel test was prepared by pressing the electrode so as to have a thickness of 100 mm.

[0123] <Electrode Evaluation> A peel test was performed on the prepared electrode for the peel test using the electrode composition for lithium ion batteries (negative electrode composition) to measure the electrode peel strength. The electrode density of the electrode for evaluating electrolyte permeability was also calculated using the same method as for the electrode for evaluating electrolyte permeability using the electrode composition for lithium ion batteries (negative electrode composition). The electrolyte permeability was evaluated using the same method as for the evaluation of the electrolyte permeability of the electrode for lithium ion batteries, except that a sodium ion battery electrolyte was used. The evaluation results are shown in Table 8.

[0124] (Preparation of Sodium Ion Battery (Positive Electrode Half-Cell) for Charge / Discharge Test) Half-cells for charge / discharge tests were prepared using the battery evaluation electrodes (positive electrodes) prepared in Examples 34 to 38 and Comparative Examples 29 to 31 as the positive electrodes. Starting from the positive electrode side, carbon-coated aluminum foil as a positive electrode current collector, the battery evaluation electrode (positive electrode), a separator [product name "#3501" manufactured by Celgard Inc.], sodium metal foil [manufactured by Kanto Chemical Co., Ltd.] as a counter electrode (negative electrode), and copper foil as a negative electrode current collector were stacked together, and after injecting a sodium ion battery electrolyte, the resulting mixture was vacuum-laminated to prevent oxygen from entering, thereby preparing batteries for charge / discharge tests. Three batteries for charge / discharge tests were prepared for each Example and Comparative Example.

[0125] <Charge / Discharge Test: Measurement of Initial Coulombic Efficiency (SiB: Cathode)> The initial coulombic efficiency of the charge / discharge test battery prepared above was evaluated using a charge / discharge measuring device "HJ-SD8" [manufactured by Hokuto Denko Corporation] at 25°C. The battery was charged to 3.7 V at a current of 0.05 C using a constant current / constant voltage charging method (also referred to as CCCV mode), and then charged while maintaining 3.7 V until the current value reached 0.0025 C. After a 10-minute pause, the battery was discharged to 2.5 V at a current of 0.05 C. The charge capacity was defined as [initial charge capacity (mAh)], and the discharge capacity was defined as [initial discharge capacity (mAh)]. The initial coulombic efficiency was calculated using the following formula, and the results are shown in Table 8. For each example and comparative example, three batteries were measured and the initial coulombic efficiency (%) was calculated, and the arithmetic average was used as the analytical value. [Initial coulombic efficiency (%)] = [Initial discharge capacity] ÷ [Initial charge capacity] × 100

[0126] <Charge-Discharge Test: Measurement of Capacity Retention Rate After Severe Test> The capacity retention rate of the charge-discharge test battery 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 3.7 V at a current of 0.05 C using a constant current charging method (also referred to as CC mode), and after a 10-minute pause, was discharged to 2.5 V at a current of 0.05 C. The discharged capacity at this time was designated as [1-Cycle Discharge Capacity (mAh)]. The battery was again charged and discharged under the same conditions, and the discharged capacity at this time was designated as [2-Cycle Discharge Capacity (mAh)]. Next, the battery was charged to 3.7 V at a current of 0.1 C, and after a 10-minute pause, was discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was designated as [3-Cycle Discharge Capacity (mAh)]. Further, the battery was charged to 3.7 V at a current of 0.5 C, and after a 10-minute rest, discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was designated as [4-cycle discharge capacity (mAh)]. Finally, the battery was charged to 3.7 V at a current of 1.0 C, and after a 10-minute rest, discharged to 2.5 V at a current of 0.1 C. The discharged capacity at this time was designated as [5-cycle discharge capacity (mAh)]. The capacity retention rate (%) after the severe test was calculated using the following formula, and the results are shown in Table 8. For each example and comparative example, the test capacity retention rate (%) was calculated for three batteries, and the arithmetic average was used as the analytical value. Capacity retention rate (%) after severe test = [5-cycle discharge capacity (mAh)] / [2-cycle discharge capacity (mAh)]

[0127]

[0128] The evaluation results shown in Tables 3 to 8 indicate that the electrodes of each Example are capable of achieving both high levels of electrolyte permeability and battery performance, and are less likely to experience a decrease in battery performance (capacity retention rate) even after repeated charge and discharge, compared with the electrodes of each Comparative Example. Furthermore, the electrode peel strength of each Example was comparable to that of an electrode containing no additive, indicating that the addition of an additive containing compound (A) hardly reduced the adhesive strength between the current collector and the electrode (electrode layer).

Claims

1. An electrode composition for a secondary battery containing an electrode active material, a binder resin, and an additive, wherein the additive contains a compound (A) represented by the following general formula (1), and the hydroxyl value of the additive is 30 KOH mg / g or less. １ -O-(AO) ｍ -R ２ (1) [In the formula, AO is an alkyleneoxy group having 2 to 4 carbon atoms, m is a number of 3 to 20 representing the average number of repetitions of the alkyleneoxy group, and (AO) ｍ is a polyoxyalkylene chain, the polyoxyalkylene chain contains ethyleneoxy groups, and the molar ratio of the ethyleneoxy groups in the polyoxyalkylene chain is 90% or more based on the total number of moles of the alkyleneoxy groups. １ is an alkyl group having 1 to 20 carbon atoms, and R ２ is an alkyl group having 1 to 2 carbon atoms.

2. The above R １ 2. The electrode composition for a secondary battery according to claim 1, wherein is an alkyl group having 1 to 13 carbon atoms.

3. The electrode composition for a secondary battery according to claim 1, wherein the hydroxyl value of the additive is 20 KOHmg / g or less.

4. The electrode composition for secondary batteries according to claim 1, wherein the content of the additive is 0.01 to 2% by weight based on the weight of the electrode active material.

5. A secondary battery electrode obtained by compression molding the electrode composition for secondary batteries according to any one of claims 1 to 4.

6. A secondary battery comprising the electrode for a secondary battery according to claim 5.

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