Binder composition for non-aqueous secondary battery electrode, slurry composition for non-aqueous secondary battery electrode, non-aqueous secondary battery electrode, and non-aqueous secondary battery

Abstract

An objective of the present invention is to provide a binder composition for non-aqueous secondary battery electrodes that makes it possible to reduce the internal resistance of a non-aqueous secondary battery. The present invention is a binder composition for non-aqueous secondary battery electrodes that contains a particulate polymer, wherein, when a least square method is used to waveform-separate a free induction decay curve of transverse relaxation of 1H measured by a pulse NMR solid echo method into two curves derived from two components, component A and component B, in ascending order of a transverse relaxation time T2, the component fraction αA of the A component of the particulate polymer is 1.0%-10.0%.

Description

Binder composition for non-aqueous secondary battery electrodes, slurry composition for non-aqueous secondary battery electrodes, electrodes for non-aqueous secondary batteries, and non-aqueous secondary batteries

[0001] The present invention relates to a binder composition for a non-aqueous secondary battery electrode, a slurry composition for a non-aqueous secondary battery electrode, an electrode for a non-aqueous secondary battery, and a non-aqueous secondary battery.

[0002] Non-aqueous secondary batteries such as lithium ion secondary batteries (hereinafter sometimes simply referred to as "secondary batteries") are small, lightweight, have high energy density, and are capable of repeated charge and discharge, and are therefore used in a wide range of applications. Therefore, in recent years, improvements to battery components such as batteries have been studied with the aim of further improving the performance of non-aqueous secondary batteries.

[0003] Here, an electrode used in a secondary battery such as a lithium-ion secondary battery typically includes a current collector and an electrode mixture layer (positive electrode mixture layer or negative electrode mixture layer) formed on the current collector. The electrode mixture layer is formed, for example, by applying a slurry composition containing an electrode active material and a binder composition containing a binding agent onto the current collector and then drying the applied slurry composition.

[0004] Development of binder compositions used in slurry compositions has been progressing in order to improve the performance of secondary batteries. For example, Patent Document 1 proposes a binder composition capable of forming a non-aqueous secondary battery electrode having excellent peel strength, which contains a particulate polymer, and the content ratios of aromatic vinyl monomer units, aliphatic conjugated diene monomer units, and carboxyl group-containing monomer units in the particulate polymer are each within a predetermined range, the ratio (Da / Db) of the average particle diameter Da of the particulate polymer measured by dynamic light scattering to the volume average particle diameter Db of the particulate polymer measured by laser diffraction scattering is within a predetermined range, and the volume average particle diameter Db of the particulate polymer is within a predetermined range.

[0005] International Publication No. 2023 / 008582

[0006] Here, the binder composition is required to reduce the internal resistance of the resulting secondary battery.

[0007] Therefore, an object of the present invention is to provide a binder composition for non-aqueous secondary battery electrodes that can reduce the internal resistance of non-aqueous secondary batteries. Another object of the present invention is to provide a slurry composition for non-aqueous secondary battery electrodes that can reduce the internal resistance of non-aqueous secondary batteries. Another object of the present invention is to provide an electrode for a non-aqueous secondary battery that can reduce the internal resistance of non-aqueous secondary batteries. Another object of the present invention is to provide a non-aqueous secondary battery with reduced internal resistance.

[0008] The present inventors have conducted extensive research to solve the above problems. １ The free induction decay curve of the transverse relaxation of H was calculated by the least squares method to obtain the transverse relaxation time T ２ When the waveform is separated into two curves derived from the two components A and B in ascending order of length, the component fraction α of the A component is Ａ The present inventors have newly found that the above-mentioned problems can be solved by a binder composition for a non-aqueous secondary battery electrode containing a particulate polymer having a specific range of .gtoreq.(.times. ...

[0009] That is, the present invention aims to advantageously solve the above-mentioned problems, and [1] the present invention is a binder composition for a non-aqueous secondary battery electrode containing a particulate polymer, wherein the particulate polymer is a polymer obtained during measurement by a solid echo method of pulsed NMR. １ The free induction decay curve of the transverse relaxation of H was calculated by the least squares method to obtain the transverse relaxation time T ２ When the waveform is separated into two curves derived from two components, A and B, in order of shortest, the component fraction α of the A component is Ａ The binder composition for a non-aqueous secondary battery electrode (hereinafter, sometimes simply referred to as the "binder composition") as described above can reduce the internal resistance of the resulting secondary battery.

[0010] Here, pulsed NMR is a method of detecting a response signal to a pulse and measuring the １ This is a method for determining the H nuclear magnetic relaxation time, and the pulse response is １The free induction decay curve of the transverse relaxation of H is obtained. The obtained free induction decay curve has a transverse relaxation time T ２ The free induction decay curves of multiple components with different values ​​are superimposed, and the transverse relaxation time T ２ The transverse relaxation time T ２ In this specification, the component fraction α of the component A of the particulate polymer can be detected. Ａ , and the component fraction α of the B component of the particulate polymer described later Ｂ , the transverse relaxation time T of the A component ２Ａ , and the transverse relaxation time T of the B component ２Ｂ can usually be measured according to the following method.

[0011] <<Preparation of Sample for Pulse NMR Measurement>> First, the binder composition of the present invention is poured into a glass petri dish so that the dry film thickness becomes approximately 1.0 mm, and dried for 3 days under conditions of 23°C x 50% RH. Thereafter, the resultant is dried for 24 hours in a vacuum dryer to prepare a sample for pulse NMR measurement.

[0012] <<Pulse NMR Measurement>> The pulse NMR measurement sample obtained above was chopped into approximately 2 mm square pieces, and the chopped pulse NMR measurement sample was filled into a 10 mm diameter glass sample tube (manufactured by Bruker, product number 1824511, 10 mm diameter, 180 mm length, flat bottom) to the extent that measurement with the pulse NMR device was possible. The sample tube was placed in a pulse NMR device (Bruker mq20), and measurement was performed using the solid echo method at 40°C under the following conditions: １ Obtain the free induction decay curve of the transverse relaxation of H. - Solid echo method - １ H resonance frequency: 20 MHz; Number of integration times: 512 times; Repetition time: 1 sec; FID observation time range: 200 μs

[0013] <<Component fraction α of component A Ａ , component fraction α of B component Ｂ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２ＢCalculation of >> The obtained free induction decay curve y(t) is separated into two curves, A component and B component. The two curves are fitted with a Gaussian function for component A and an exponential function for component B. The following equation (1) is used for fitting: y(t) = A Ａ ×exp [-(t / T ２Ａ ) ２ ]+A Ｂ ×exp [-(t / T ２Ｂ ) )]...(1) In equation (1), y(t) is normalized based on its maximum value and ranges from 0 to 1. t is time. A Ａ is the transverse relaxation time T in pulsed NMR measurement ２ is the intensity of the short A component at t = 0, A Ｂ is the transverse relaxation time T in pulsed NMR measurement ２ is the intensity of the long B component at t = 0, T ２Ａ is the transverse relaxation time of the A component, T ２Ｂ indicates the transverse relaxation time of the B component. The free induction decay curve was measured three times using the solid echo method. Ａ , A Ｂ , T ２Ａ , and T ２Ｂ The average values ​​of the strength A of the A component in the particulate polymer at t=0 are calculated. Ａ , B component intensity A at t = 0 Ｂ , the transverse relaxation time T of the A component ２Ａ , and the transverse relaxation time T of the B component ２Ｂ Then, "A Ａ / (A Ａ +A Ｂ ) × 100 [%]" is the component fraction α of component A Ａ Toshio, "A Ｂ / (A Ａ +A Ｂ ) × 100 [%]" is the component fraction α of component B Ｂ In addition, A Ａ , A Ｂ , T ２Ａ , and T ２Ｂ The calculation is obtained during pulsed NMR solid echo measurement. １The data of the free induction decay curve of the transverse relaxation of H can be made into a text file, read into Microsoft Excel spreadsheet software, and used for the approximate calculation function. Ａ , A Ｂ , T ２Ａ , and T ２Ｂ The calculation of can also be performed using analysis software "TDNMR-A" manufactured by Bruker.

[0014] [2] In the non-aqueous secondary battery electrode binder composition according to [1] above, the transverse relaxation time T ２Ａ The transverse relaxation time T of the A component is preferably 0.001 msec or more and 0.1 msec or less. ２Ａ If the transverse relaxation time T ２Ａ When is equal to or less than the above upper limit, the internal resistance of the obtained secondary battery can be effectively reduced.

[0015] [3] In the binder composition for a non-aqueous secondary battery electrode according to the above [1] or [2], the particulate polymer preferably contains an aromatic vinyl monomer unit. If the particulate polymer contains an aromatic vinyl monomer unit, the internal resistance of the resulting secondary battery can be effectively reduced.

[0016] [4] In the binder composition for a non-aqueous secondary battery electrode according to any one of [1] to [3] above, the volume average particle diameter of the particulate polymer is preferably 100 nm or more and 300 nm or less. When the volume average particle diameter of the particulate polymer is equal to or greater than the lower limit, the internal resistance of the resulting secondary battery can be effectively reduced. Furthermore, the injectability of the electrolyte solution into the electrode mixture layer can be improved. On the other hand, when the volume average particle diameter of the particulate polymer is equal to or less than the upper limit, the viscosity of the binder composition can be maintained well. In this specification, the volume average particle diameter refers to the particle diameter (D50) at which the cumulative volume calculated from the smallest diameter side in the particle size distribution becomes 50%, and can be measured according to the method described in the examples of this specification.

[0017] [5] In the binder composition for a non-aqueous secondary battery electrode according to any one of [1] to [4] above, the particulate polymer preferably has an insoluble fraction in tetrahydrofuran of 70 mass % or more. When the insoluble fraction in tetrahydrofuran of the particulate polymer is equal to or greater than the lower limit, the viscosity of the binder composition can be maintained at a good level.

[0018] In this specification, the insoluble fraction of a particulate polymer in tetrahydrofuran (THF) (hereinafter sometimes referred to as "THF insoluble fraction") can usually be measured by the following method. First, the binder composition of the present invention is dried in an environment of 50% humidity and 23 to 25°C temperature to form a film having a thickness of 1±0.3 mm. Next, the formed film is dried in a vacuum dryer at 60°C for 10 hours. Thereafter, the dried film is cut into 3 to 5 mm square pieces, and approximately 1 g is precisely weighed. Here, the mass of the film piece obtained by cutting is defined as w0. The obtained film piece is immersed in 50 g of tetrahydrofuran (THF) for 24 hours. Thereafter, the film piece removed from the THF is vacuum dried at a temperature of 105°C for 3 hours, and the mass w1 of the insoluble portion is measured. Then, the THF insoluble fraction is calculated using the following calculation formula (2): THF-insoluble fraction (mass %)=(w1 / w0)×100 (2) For example, the THF-insoluble fraction of the particulate polymer can be measured according to the method described in the Examples.

[0019] Another object of the present invention is to advantageously solve the above-mentioned problems, and [6] the present invention provides a slurry composition for a non-aqueous secondary battery electrode, comprising an electrode active material and any one of the binder compositions for a non-aqueous secondary battery electrode described above in [1] to [5]. The above-mentioned slurry composition for a non-aqueous secondary battery electrode (hereinafter sometimes simply referred to as the "slurry composition") can reduce the internal resistance of the resulting secondary battery.

[0020] Another object of the present invention is to advantageously solve the above-mentioned problems, and [7] the present invention provides an electrode for a non-aqueous secondary battery, comprising an electrode mixture layer formed using the slurry composition for a non-aqueous secondary battery electrode according to [6]. Such an electrode for a non-aqueous secondary battery (hereinafter sometimes simply referred to as "electrode") can reduce the internal resistance of the resulting secondary battery.

[0021] Another object of the present invention is to advantageously solve the above-mentioned problems, and [8] the present invention provides a non-aqueous secondary battery including a positive electrode, a negative electrode, a separator, and an electrolyte solution, wherein at least one of the positive electrode and the negative electrode is the non-aqueous secondary battery electrode according to [7] above. The secondary battery described above has reduced internal resistance.

[0022] According to the present invention, a binder composition for a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a slurry composition for a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a non-aqueous secondary battery with reduced internal resistance can be provided.

[0023] Hereinafter, embodiments of the present invention will be described in detail. Here, the binder composition of the present invention can be used to prepare the slurry composition of the present invention. The slurry composition prepared using the binder composition of the present invention can be used to manufacture electrodes for secondary batteries such as lithium-ion secondary batteries. Furthermore, the secondary battery of the present invention is characterized by using the electrode of the present invention formed using the slurry composition of the present invention. Note that the binder composition, slurry composition, and electrode of the present invention are preferably for negative electrodes, and the secondary battery of the present invention preferably uses the electrode of the present invention as a negative electrode.

[0024] (Binder composition for non-aqueous secondary battery electrode) The binder composition for non-aqueous secondary battery electrode of the present invention contains a particulate polymer and may generally further contain a solvent. The particulate polymer is a polymer that is obtained during measurement by the solid echo method of pulse NMR. １The free induction decay curve of the transverse relaxation of H was calculated by the least squares method to obtain the transverse relaxation time T ２ When the waveform is separated into two curves derived from the two components A and B in ascending order of length, the component fraction α of the A component is Ａ The content of the binder composition of the present invention is 1.0% or more and 10.0% or less. Note that the binder composition of the present invention does not usually contain an electrode active material.

[0025] <Particulate polymer> The particulate polymer is a component that functions as a binder, and can prevent components such as the electrode active material from being detached from the electrode mixture layer formed using a slurry composition containing the binder composition. Here, the particulate polymer is preferably water-insoluble particles. In this specification, the term "water-insoluble" for polymer particles means that when 0.5 g of the polymer is dissolved in 100 g of water at a temperature of 25°C, the insoluble content is 90 mass% or more.

[0026] The particulate polymer contained in the binder composition of the present invention has a specific surface area obtained by pulse NMR solid echo method measurement. １ The free induction decay curve of the transverse relaxation of H was calculated by the least squares method to obtain the transverse relaxation time T ２ When the waveform is separated into two curves derived from the two components A and B in ascending order of length, the component fraction α of the A component is Ａ The use of the particulate polymer in the binder composition can reduce the internal resistance of the resulting secondary battery. The reason for this is that the transverse relaxation time T ２ A component with a short time is a component with low molecular mobility and hardness (corresponding to component A), and the transverse relaxation time T ２ can mean the long component (corresponding to component B), and the component fraction α of component A Ａ It is presumed that a particulate polymer having a molecular weight of 1.0% or more and 10.0% or less has a good balance between molecular mobility and hardness, and as a result, the internal resistance of the resulting secondary battery can be reduced.

[0027] <<Properties of particulate polymer>> Component fraction α of component A in particulate polymer Ａis required to be 1.0% or more, preferably 1.5% or more, and is required to be 10.0% or less, preferably 8.0% or less, and more preferably 6.5% or less. Ａ The component fraction α of the component A in the particulate polymer must be 1.0% or more and 10.0% or less, preferably 1.5% or more and 8.0% or less, and more preferably 1.5% or more and 6.5% or less. Ａ is equal to or greater than the lower limit, the internal resistance of the resulting secondary battery can be reduced. Also, the internal resistance of a secondary battery obtained from an electrode having an electrode mixture layer obtained by high-speed coating can be reduced. On the other hand, the component fraction α of the component A in the particulate polymer Ａ When the content of the binder composition is equal to or less than the upper limit, the viscosity of the binder composition can be maintained at a good level. In addition, the internal resistance of the resulting secondary battery can be reduced, and the cycle characteristics of the resulting secondary battery can be improved.

[0028] Component fraction α of component B in particulate polymer Ｂ is preferably 90.0% or more, more preferably 92.0% or more, and even more preferably 93.5% or more, and is necessarily 99.0% or less, and preferably 98.5% or less. Ｂ is preferably 90.0% or more and 99.0% or less, more preferably 92.0% or more and 98.5% or less, and even more preferably 93.5% or more and 98.5% or less. Ｂ When the component fraction α of the particulate polymer B is equal to or greater than the lower limit, the viscosity of the binder composition can be maintained at a good level. In addition, the internal resistance of the resulting secondary battery can be effectively reduced, and the cycle characteristics of the resulting secondary battery can be improved. Ｂ If the value is equal to or less than the upper limit, the internal resistance of the resulting secondary battery can be effectively reduced. Also, the internal resistance of a secondary battery obtained from an electrode having an electrode mixture layer obtained by high-speed coating can be reduced.

[0029] Transverse relaxation time T of component A of the particulate polymer ２Ａis preferably 0.001 msec or more, more preferably 0.005 msec or more, even more preferably 0.008 msec or more, even more preferably 0.0085 msec or more, and is preferably 0.1 msec or less, more preferably 0.05 msec or less, and even more preferably 0.025 msec or less. ２Ａ is preferably 0.001 msec or more and 0.1 msec or less, more preferably 0.005 msec or more and 0.05 msec or less, even more preferably 0.008 msec or more and 0.025 msec or less, and even more preferably 0.0085 msec or more and 0.025 msec or less. ２Ａ If the transverse relaxation time T ２Ａ When is equal to or less than the above upper limit, the internal resistance of the obtained secondary battery can be effectively reduced.

[0030] Transverse relaxation time T of component B of the particulate polymer ２Ｂ is preferably 0.1 msec or more, more preferably 0.4 msec or more, and is preferably 6 msec or less, more preferably 3 msec or less. ２Ｂ The transverse relaxation time T of the B component is preferably 0.1 msec or more and 6 msec or less, and more preferably 0.4 msec or more and 3 msec or less. ２Ｂ If the transverse relaxation time T ２Ｂ When is equal to or less than the above upper limit, the internal resistance of the obtained secondary battery can be effectively reduced.

[0031] The component fraction α of the particulate polymer A Ａ , component fraction α of B component Ｂ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２Ｂcan be adjusted by, for example, the type and amount of the monomer used to form the particulate polymer, the polymerization method and polymerization conditions, etc.

[0032] The THF-insoluble fraction of the particulate polymer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 93% by mass or more, and even more preferably 95% by mass or more. When the THF-insoluble fraction of the particulate polymer is equal to or greater than the above lower limit, the viscosity of the binder composition can be maintained favorably. The THF-insoluble fraction of the particulate polymer is, for example, 99% by mass or less, and may be 97% by mass or less. The THF-insoluble fraction of the particulate polymer is preferably 70% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 97% by mass or less, even more preferably 90% by mass or more and 97% by mass or less, even more preferably 93% by mass or more and 97% by mass or less, and even more preferably 95% by mass or more and 97% by mass or less. The THF-insoluble fraction of the particulate polymer can be adjusted by, for example, the type and amount of the monomer used to form the particulate polymer, the polymerization method and polymerization conditions, and the like.

[0033] The volume average particle diameter of the particulate polymer is preferably 100 nm or more, more preferably 120 nm or more, and preferably 300 nm or less, and more preferably 170 nm or less. When the volume average particle diameter of the particulate polymer is equal to or greater than the above-mentioned lower limit, the internal resistance of the resulting secondary battery can be effectively reduced. In addition, the injectability of the electrolyte solution into the electrode mixture layer can be improved. On the other hand, when the volume average particle diameter of the particulate polymer is equal to or less than the above-mentioned upper limit, the viscosity of the binder composition can be maintained well.

[0034] <<Composition of Particulate Polymer>> The particulate polymer is not particularly limited as long as it has the above-mentioned predetermined physical properties, and may optionally contain aromatic vinyl monomer units, aliphatic conjugated diene monomer units, carboxylic acid group-containing monomer units, (meth)acrylic acid ester monomer units, vinyl cyanide-based monomer units, etc. The particulate polymer may optionally further contain monomer units other than aromatic vinyl monomer units, aliphatic conjugated diene monomer units, carboxylic acid group-containing monomer units, (meth)acrylic acid ester monomer units, and vinyl cyanide-based monomer units (hereinafter, sometimes referred to as "other monomer units"). In this specification, when a particulate polymer "contains a monomer unit," it means that "a polymer obtained using that monomer contains a structural unit derived from the monomer." In this specification, "(meth)acrylic" means acrylic and / or methacrylic.

[0035] -Aromatic vinyl monomer unit- Examples of aromatic vinyl monomers that can form aromatic vinyl monomer units include aromatic monovinyl compounds such as styrene, α-methylstyrene, p-t-butylstyrene, butoxystyrene, vinyltoluene, chlorostyrene, and vinylnaphthalene. Among these, styrene is preferred. These can be used alone or in combination of two or more, but it is preferred to use one type alone.

[0036] The content of the aromatic vinyl monomer units in the particulate polymer is preferably 5% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 50% by mass or less, and even more preferably 35% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. The content of the aromatic vinyl monomer units in the particulate polymer is preferably 5% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 55% by mass or less, even more preferably 20% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 35% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. If the content of the aromatic vinyl monomer units in the particulate polymer is above the above lower limit, the stability of the resulting slurry composition can be further improved. On the other hand, when the content ratio of the aromatic vinyl monomer unit in the particulate polymer is not more than the above upper limit, the peel strength of the obtained electrode and the peel strength during high-speed coating can be improved. １ It can be measured using a nuclear magnetic resonance (NMR) method such as H-NMR.

[0037] - Aliphatic conjugated diene monomer unit - Examples of aliphatic conjugated diene monomers that can form aliphatic conjugated diene monomer units include aliphatic conjugated diene compounds having 4 or more carbon atoms, such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred, because they can maintain the viscosity of the binder composition well and improve the moisture resistance of the resulting electrode. These can be used alone or in combination of two or more.

[0038] The content of the aliphatic conjugated diene monomer units in the particulate polymer is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 55% by mass or more, and preferably 90% by mass or less, and more preferably 80% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. The content of the aliphatic conjugated diene monomer units in the particulate polymer is preferably 20% by mass or more and 90% by mass or less, more preferably 25% by mass or more and 80% by mass or less, even more preferably 30% by mass or more and 80% by mass or less, and even more preferably 55% by mass or more and 80% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. If the content of the aliphatic conjugated diene monomer units in the particulate polymer is not less than the above lower limit, the peel strength of the obtained electrode and the peel strength during high-speed coating can be improved. On the other hand, when the content ratio of the aliphatic conjugated diene monomer unit in the particulate polymer is equal to or less than the above upper limit, the stability of the resulting slurry composition can be improved.

[0039] Carboxylic Acid Group-Containing Monomer Units Carboxylic acid group-containing monomers that can form carboxylic acid group-containing monomer units include monocarboxylic acids and their derivatives, dicarboxylic acids and their acid anhydrides, and derivatives thereof. Examples of monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Examples of monocarboxylic acid derivatives include 2-ethylacrylic acid, isocrotonic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, and α-chloro-β-E-methoxyacrylic acid. Examples of dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of dicarboxylic acid derivatives include methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, and maleic acid monoesters such as nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate. Examples of the acid anhydrides of dicarboxylic acids include maleic anhydride, acrylic anhydride, methyl maleic anhydride, dimethyl maleic anhydride, etc. Furthermore, as the carboxylic acid group-containing monomer, an acid anhydride that generates a carboxylic acid group by hydrolysis can also be used.

[0040] The above-mentioned carboxylic acid group-containing monomers can be used alone or in combination of two or more. Among these acid group-containing monomers, acrylic acid and methacrylic acid are more preferred, and methacrylic acid is more preferred, because they can improve the stability of the resulting slurry composition and the peel strength of the resulting electrode and the peel strength during high-speed coating.

[0041] The content of the carboxylic acid group-containing monomer units contained in the particulate polymer is preferably 2% by mass or more, more preferably 2.5% by mass or more, even more preferably 3% by mass or more, and preferably 9% by mass or less, more preferably 5% by mass or less, and even more preferably 4% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. The content of the carboxylic acid group-containing monomer units in the particulate polymer is preferably 2% by mass or more and 9% by mass or less, more preferably 2.5% by mass or more and 5% by mass or less, and even more preferably 3% by mass or more and 4% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. When the content of the carboxylic acid group-containing monomer units in the particulate polymer is equal to or greater than the lower limit, the stability of the binder composition and the slurry composition can be improved. On the other hand, when the content of the carboxylic acid group-containing monomer units in the particulate polymer is equal to or less than the upper limit, the viscosity of the binder composition can be maintained at a good level.

[0042] -(Meth)acrylic acid ester monomer unit- Examples of (meth)acrylic acid ester monomers that can form (meth)acrylic acid ester monomer units include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, and n-butyl methacrylate; methacrylic acid alkyl esters such as 2-hydroxyethyl acrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, and 2-ethylhexyl methacrylate; and hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxymethacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, and 3-chloro-2-hydroxypropyl methacrylate. These may be used alone or in combination of two or more in any ratio.

[0043] The content of the (meth)acrylic acid ester monomer units contained in the particulate polymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 5% by mass or less, more preferably 2% by mass or less, when the total amount of repeating units (total monomer units) in the particulate polymer is 100% by mass.

[0044] —Vinyl cyanide-based monomer unit— Examples of vinyl cyanide-based monomers that can form vinyl cyanide-based monomer units include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, etc. These may be used alone or in combination of two or more in any ratio.

[0045] The content of the vinyl cyanide monomer units contained in the particulate polymer is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 5% by mass or less, more preferably 2% by mass or less, when the total repeating units (total monomer units) in the particulate polymer is 100% by mass.

[0046] -Other Monomer Units- Monomers that can form other monomer units are not particularly limited, and examples thereof include unsaturated carboxylic acid amide monomers.

[0047] Examples of the unsaturated carboxylic acid amide monomer include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N,N-dimethyl acrylamide, etc. These may be used alone or in combination of two or more in any ratio.

[0048] The content of other monomer units in the particulate polymer is preferably 5% by mass or less, more preferably 1% by mass or less, and particularly preferably 0% by mass, when the total repeating units (total monomer units) in the particulate polymer is taken as 100% by mass. That is, it is particularly preferable that the particulate polymer does not contain other monomer units.

[0049] -Preferred Composition of Particulate Polymer- The particulate polymer preferably contains an aromatic vinyl monomer unit, more preferably contains an aromatic vinyl monomer unit, a conjugated diene monomer unit, and a carboxylic acid group-containing monomer unit, because this can effectively reduce the internal resistance of the resulting secondary battery. The particulate polymer is further preferably a polymer containing styrene, 1,3-butadiene, and (meth)acrylic acid, or a polymer containing styrene, isoprene, and (meth)acrylic acid, and even more preferably a polymer containing styrene, 1,3-butadiene, and (meth)acrylic acid.

[0050] <<Structure of Particulate Polymer>> The particulate polymer may be a particulate polymer having a uniform monomer unit composition (type and content ratio of monomer units), or may be a particulate polymer having a non-uniform monomer unit composition. Examples of particulate polymers having a non-uniform monomer unit composition include particulate polymers having a core-shell structure comprising a core portion and a shell portion covering at least a part of the outer surface of the core portion, with the core portion and the shell portion having different monomer unit compositions, and particulate polymers having a core portion only having a different monomer unit composition. Note that particulate polymers having a core-shell structure can be obtained, for example, by two-stage polymerization, which will be described later.

[0051] From the viewpoint of further improving the peel strength of the obtained electrode and reducing the internal resistance of the obtained secondary battery, it is preferable that the particulate polymer has a core-shell structure including a core portion made of a copolymer containing aromatic vinyl monomer units, aliphatic conjugated diene monomer units, and carboxylic acid group-containing monomer units, and a shell portion made of a polymer containing aromatic vinyl monomer units and carboxylic acid group-containing monomer units and may optionally contain (meth)acrylic acid ester monomer units and vinyl cyanide monomer units. Note that the core-shell structure of the particulate polymer may further contain components other than the core portion and the shell portion, but is preferably made of only the core portion and the shell portion.

[0052] <<Particulate Polymer Content>> The particulate polymer content in the binder composition is preferably 20% by mass or more, more preferably 25% by mass or more, and is preferably 60% by mass or less, more preferably 50% by mass or less.

[0053] <<Method for Preparing Particulate Polymer>> The particulate polymer can be polymerized according to a known polymerization method, for example, a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, etc. As the polymerization reaction, addition polymerization such as ionic polymerization, radical polymerization, living radical polymerization, etc. can be used.

[0054] In the polymerization reaction, commonly used additives such as a molecular weight modifier, an emulsifier, a dispersant, a polymerization initiator, a polymerization aid, etc. The amounts of these additives used may be those commonly used.

[0055] The preparation of the particulate polymer is not particularly limited, but can be carried out, for example, by the following procedure.

[0056] First, the above-mentioned monomers are mixed with water, an emulsifier, and a polymerization initiator, and the mixture (emulsion) is heated to carry out a polymerization reaction. When a predetermined polymerization conversion rate is reached, the mixture is cooled to terminate the reaction, yielding a mixture containing a particulate polymer. Unreacted monomers are removed from the mixture. The pH of the mixture is appropriately adjusted to obtain an aqueous dispersion of the particulate polymer. Here, a particulate polymer having a core-shell structure can be obtained by adding the monomers in stages. For example, when an aromatic vinyl monomer, an aliphatic conjugated diene monomer, and a carboxylic acid group-containing monomer are used to prepare a particulate polymer having a core-shell structure, the entire amount of the aliphatic conjugated diene monomer and a portion of the aromatic vinyl monomer and the carboxylic acid group-containing monomer may be added first to carry out the polymerization reaction, and then the remaining aromatic vinyl monomer and the carboxylic acid group-containing monomer may be added to carry out the polymerization reaction (two-stage polymerization).

[0057] Here, when the particulate polymer is prepared by two-stage polymerization, the total amount of monomers added in the first stage is preferably 85 parts by mass or more, more preferably 90 parts by mass or more, even more preferably 92 parts by mass or more, and preferably 98 parts by mass or less, more preferably 96 parts by mass or less, and even more preferably 94 parts by mass or less, based on 100 parts by mass of all monomers added in the preparation of the particulate polymer. If the total amount of monomers added in the first stage is equal to or greater than the lower limit, the peel strength of the resulting electrode can be improved. On the other hand, if the total amount of monomers added in the first stage is equal to or less than the upper limit, the internal resistance of the resulting secondary battery can be effectively reduced.

[0058] The amount of the aromatic vinyl monomer added in the first stage is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and preferably 40 parts by mass or less, more preferably 25 parts by mass or less, based on 100 parts by mass of all the monomers added in the first stage. When the amount of the aromatic vinyl monomer added in the first stage is within the above range, the internal resistance of the resulting secondary battery can be effectively reduced.

[0059] The amount of the aliphatic conjugated diene monomer added in the first stage is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and preferably 88 parts by mass or less, more preferably 80 parts by mass or less, relative to 100 parts by mass of all the monomers added in the first stage. When the amount of the aliphatic conjugated diene monomer added in the first stage is within the above range, the peel strength of the resulting electrode can be improved.

[0060] The amount of the carboxylic acid group-containing monomer added in the first stage is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 5 parts by mass or less, more preferably 2 parts by mass or less, relative to 100 parts by mass of all the monomers added in the first stage. When the amount of the carboxylic acid group-containing monomer added in the first stage is within the above range, the peel strength of the resulting electrode can be improved.

[0061] Furthermore, when the particulate polymer is prepared by two-stage polymerization, the total amount of monomers added in the second stage is preferably 2 parts by mass or more, more preferably 4 parts by mass or more, even more preferably 6 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, based on 100 parts by mass of all monomers added in the preparation of the particulate polymer. If the total amount of monomers added in the second stage is equal to or greater than the above-mentioned lower limit, the internal resistance of the resulting secondary battery can be effectively reduced. On the other hand, if the total amount of monomers added in the second stage is equal to or less than the above-mentioned upper limit, the peel strength of the resulting electrode can be improved.

[0062] The amount of aromatic vinyl monomer added in the second stage is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more, and is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less, based on 100 parts by mass of all monomers added in the second stage. If the amount of aromatic vinyl monomer added in the second stage is within the above range, the internal resistance of the resulting secondary battery can be effectively reduced.

[0063] The amount of the carboxylic acid group-containing monomer added in the second stage is preferably 15 parts by mass or more, more preferably 25 parts by mass or more, and even more preferably 35 parts by mass or more, and is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less, relative to 100 parts by mass of all the monomers added in the second stage. If the amount of the carboxylic acid group-containing monomer added in the second stage is within the above range, the peel strength of the resulting electrode can be improved.

[0064] The amount of the (meth)acrylic acid ester monomer added in the second stage is preferably 2.5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 25 parts by mass or less, more preferably 20 parts by mass or less, based on 100 parts by mass of all the monomers added in the second stage. If the amount of the (meth)acrylic acid ester monomer added in the second stage is within the above range, the internal resistance of the resulting secondary battery can be effectively reduced.

[0065] The amount of the vinyl cyanide monomer added in the second stage is preferably 2.5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 25 parts by mass or less, more preferably 20 parts by mass or less, based on 100 parts by mass of all the monomers added in the second stage. If the amount of the vinyl cyanide monomer added in the second stage is within the above range, the internal resistance of the resulting secondary battery can be effectively reduced.

[0066] <Solvent> Examples of solvents that may be contained in the binder composition of the present invention include water and water-soluble organic solvents. Among these, water is preferred. These solvents may be used alone or in combination of two or more. Here, the proportion of water in the solvent is preferably 90% by mass or more, when the total solvent is taken as 100% by mass.

[0067] <Other Components> The binder composition of the present invention may contain other components as long as the object of the present invention is not impaired. Examples of other components include antioxidants, antifoaming agents, dispersants, pH adjusters, etc. One type of other component may be used alone, or two or more types may be used in combination at any ratio.

[0068] <Method for preparing binder composition for non-aqueous secondary battery electrode> The binder composition of the present invention is not particularly limited, and can be prepared by mixing a particulate polymer and other components that can be used optionally in the presence of a solvent, etc. When the binder composition is prepared using an aqueous dispersion of a particulate polymer, the liquid contained in the aqueous dispersion may be used as it is as a solvent for the binder composition.

[0069] (Slurry composition for non-aqueous secondary battery electrode) The slurry composition of the present invention is a composition used for forming an electrode mixture layer of an electrode, and contains the above-mentioned binder composition and an electrode active material. That is, the slurry composition of the present invention contains the above-mentioned particulate polymer and electrode active material, and may further contain a solvent and other components, as desired. Furthermore, since the slurry composition of the present invention contains the above-mentioned binder composition, the internal resistance of the resulting secondary battery can be reduced.

[0070] <Binder composition> The binder composition used is the binder composition of the present invention described above, which contains a particulate polymer and may optionally further contain a solvent and other components. The amount of the binder composition in the slurry composition is not particularly limited. For example, the amount of the binder composition can be such that the amount of the particulate polymer is 0.5 parts by mass or more and 15 parts by mass or less, calculated as a solid content, per 100 parts by mass of the electrode active material.

[0071] <Electrode active material> The electrode active material is not particularly limited, and known electrode active materials used in secondary batteries can be used. Specifically, for example, the electrode active material that can be used in the electrode mixture layer of a lithium ion secondary battery, which is an example of a secondary battery, is not particularly limited, and the following electrode active materials can be used.

[0072] <<Positive Electrode Active Material>> The positive electrode active material to be blended in the positive electrode composite layer of the positive electrode of the lithium ion secondary battery may be, for example, a compound containing a transition metal, such as a transition metal oxide, a transition metal sulfide, or a composite metal oxide of lithium and a transition metal. Examples of the transition metal include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Mo. Specifically, the positive electrode active material is not particularly limited, and may be, for example, lithium-containing cobalt oxide (LiCoO ２ ), lithium manganese oxide (LiMn ２ O ４ ), lithium-containing nickel oxide (LiNiO ２ ), Co—Ni—Mn lithium-containing composite oxide, Ni—Mn—Al lithium-containing composite oxide, Ni—Co—Al lithium-containing composite oxide, olivine-type lithium iron phosphate (LiFePO ４ ), olivine-type lithium manganese phosphate (LiMnPO ４ ), Li １＋ｘ Mn ２－ｘ O ４ (0<X<2) Lithium-excess spinel compound represented by Li[Ni ０．１７ Li ０．２ Co ０．０７ Mn ０．５６ ]O ２ , LiNi ０．５ Mn １．５ O ４ The above-mentioned positive electrode active materials may be used singly or in combination of two or more.

[0073] <<Negative Electrode Active Material>> Examples of negative electrode active materials to be incorporated into the negative electrode composite layer of the negative electrode of a lithium ion secondary battery include carbon-based negative electrode active materials, metal-based negative electrode active materials, and negative electrode active materials that combine these. Here, the carbon-based negative electrode active material refers to an active material that has a carbon skeleton and is capable of inserting (or "doping") lithium. Specific examples of carbon-based negative electrode active materials include carbonaceous materials such as coke, mesocarbon microbeads (MCMB), mesophase pitch-based carbon fiber, pyrolytic vapor-grown carbon fiber, phenolic resin calcined body, polyacrylonitrile-based carbon fiber, pseudo-isotropic carbon, furfuryl alcohol resin calcined body (PFA), and hard carbon, as well as graphitic materials such as natural graphite and artificial graphite. Furthermore, the term "metal-based negative electrode active material" refers to an active material containing a metal, typically containing an element capable of inserting lithium in its structure, and having a theoretical electrical capacity per unit mass of 500 mAh / g or more when lithium is inserted. Examples of metal-based active materials include lithium metal, elemental metals capable of forming lithium alloys (e.g., Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn, Sr, Zn, Ti, etc.), and oxides, sulfides, nitrides, silicides, carbides, phosphides, etc. thereof. Further examples include oxides such as lithium titanate. The above-mentioned negative electrode active materials may be used alone or in combination of two or more.

[0074] <Solvent> The solvent that can be contained in the slurry composition may be the same as the solvents listed above in the "Non-aqueous secondary battery electrode binder composition."

[0075] <Other Components> Other components that can be blended into the slurry composition are not particularly limited, and include thickeners, conductive materials, and the same components as those that can be blended into the binder composition of the present invention. Note that the other components may be used alone or in combination of two or more in any ratio.

[0076] <Preparation of Slurry Composition for Non-Aqueous Secondary Battery Electrode> The method for preparing the slurry composition is not particularly limited. For example, the binder composition, the electrode active material, and other components used as needed can be mixed in the presence of a solvent to prepare the slurry composition. The solvent used in preparing the slurry composition also includes the solvent contained in the binder composition. The mixing method is not particularly limited, and mixing can be performed using a commonly used stirrer, disperser, or the like.

[0077] (Electrode for Non-Aqueous Secondary Battery) The electrode for a non-aqueous secondary battery of the present invention includes an electrode mixture layer formed using the above-described slurry composition for a non-aqueous secondary battery electrode. Therefore, the electrode mixture layer is composed of a dried product of the above-described slurry composition, and typically contains an electrode active material and a component derived from a particulate polymer, and optionally further contains other components. The components contained in the electrode mixture layer are those contained in the above-described slurry composition for a non-aqueous secondary battery electrode, and the preferred abundance ratio of each component is the same as the preferred abundance ratio of each component in the slurry composition. Furthermore, although the particulate polymer exists in particulate form in the slurry composition, it may be in particulate form or any other shape in the electrode mixture layer formed using the slurry composition. Furthermore, since the electrode mixture layer of the non-aqueous secondary battery electrode electrode of the present invention is formed using the above-described slurry composition for a non-aqueous secondary battery electrode, the internal resistance of the resulting secondary battery can be reduced.

[0078] <Production of Electrode for Non-Aqueous Secondary Battery> Here, the electrode mixture layer of the electrode for a non-aqueous secondary battery of the present invention can be formed using, for example, the following methods. 1) A method of applying the slurry composition of the present invention to the surface of a current collector and then drying it; 2) A method of immersing a current collector in the slurry composition of the present invention and then drying it; and 3) A method of applying the slurry composition of the present invention to a release substrate and drying it to produce an electrode mixture layer, and then transferring the obtained electrode mixture layer to the surface of a current collector. Among these, method 1) is particularly preferred because it makes it easy to control the layer thickness of the electrode mixture layer. Method 1) specifically includes a step of applying the slurry composition to a current collector (application step) and a step of drying the slurry composition applied to the current collector to form an electrode mixture layer on the current collector (drying step).

[0079] <<Coating Step>> The method for applying the slurry composition onto the current collector is not particularly limited, and known methods can be used. Specifically, examples of the application method include a doctor blade method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, and a brush coating method. In this case, the slurry composition may be applied to only one side of the current collector, or may be applied to both sides. The thickness of the slurry film on the current collector after application and before drying can be appropriately set depending on the thickness of the electrode mixture layer obtained by drying.

[0080] Here, the current collector to which the slurry composition is applied is made of a material that is electrically conductive and electrochemically durable. Specifically, the current collector may be made of, for example, iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, etc. Note that one of the above materials may be used alone, or two or more may be used in combination in any ratio.

[0081] <<Drying Step>> The method for drying the slurry composition on the current collector is not particularly limited and any known method can be used, for example, a drying method using warm air, hot air, or low-humidity air, a vacuum drying method, or a drying method using infrared rays, an electron beam, etc. By drying the slurry composition on the current collector in this manner, an electrode mixture layer can be formed on the current collector, and a nonaqueous secondary battery electrode including the current collector and the electrode mixture layer can be obtained.

[0082] After the drying step, the electrode mixture layer may be subjected to a pressure treatment using a mold press, a roll press, or the like. The pressure treatment improves the adhesion between the electrode mixture layer and the current collector and also increases the density of the resulting electrode mixture layer. In addition, when the electrode mixture layer contains a curable polymer, it is preferable to cure the polymer after the electrode mixture layer is formed.

[0083] (Nonaqueous secondary battery) The nonaqueous secondary battery of the present invention includes a positive electrode, a negative electrode, an electrolyte, and a separator, and uses the above-described nonaqueous secondary battery electrode as at least one of the positive electrode and the negative electrode. The nonaqueous secondary battery of the present invention is manufactured using the above-described nonaqueous secondary battery electrode as at least one of the positive electrode and the negative electrode, and therefore has reduced internal resistance. Hereinafter, a description will be given of a case where the secondary battery is a lithium-ion secondary battery as an example, but the present invention is not limited to the following example.

[0084] <Electrode> Electrodes other than the above-described electrode for a nonaqueous secondary battery of the present invention that can be used in the nonaqueous secondary battery of the present invention are not particularly limited, and known electrodes used in the manufacture of secondary batteries can be used. Specifically, electrodes other than the above-described electrode for a nonaqueous secondary battery of the present invention can be electrodes formed by forming an electrode mixture layer on a current collector using a known manufacturing method.

[0085] <Electrolyte> As the electrolyte, an organic electrolyte solution in which a supporting electrolyte is dissolved in an organic solvent is usually used. As the supporting electrolyte of a lithium ion secondary battery, for example, a lithium salt is used. As the lithium salt, for example, LiPF ６ , LiAsF ６ , LiBF ４ , LiSbF６ , LiAlCl ４ , LiClO ４ , C.F. ３ SO ３ Li, C ４ F ９ SO ３ Li, CF ３ COOLi, (CF ３ CO) ２ NLi, (CF ３ SO ２ ) ２ NLi, (C ２ F ５ SO ２ Among them, LiPF is preferred because it is easily soluble in solvents and shows a high degree of dissociation. ６ , LiClO ４ , C.F. ３ SO ３ Li is preferred. Note that one type of electrolyte may be used alone, or two or more types may be used in combination at any ratio. Generally, the use of a supporting electrolyte with a higher degree of dissociation tends to result in higher lithium ion conductivity, so the lithium ion conductivity can be adjusted by the type of supporting electrolyte.

[0086] The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte. Suitable examples include carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), ethyl methyl carbonate (EMC), and vinylene carbonate (VC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; and sulfur-containing compounds such as sulfolane and dimethyl sulfoxide. Mixtures of these solvents may also be used. Among these, carbonates are preferred due to their high dielectric constant and wide stable potential range. Generally, the lower the viscosity of the solvent used, the higher the lithium ion conductivity. Therefore, the lithium ion conductivity can be adjusted by the type of solvent. The concentration of the electrolyte in the electrolyte can be adjusted as appropriate. Known additives can also be added to the electrolyte.

[0087] <Separator> The separator is not particularly limited, and for example, those described in JP 2012-204303 A can be used. Among these, a microporous film made of a polyolefin resin (polyethylene, polypropylene, polybutene, polyvinyl chloride) is preferred because it allows the thickness of the entire separator to be thin, thereby increasing the proportion of electrode active material in the secondary battery and increasing the capacity per volume.

[0088] The secondary battery of the present invention can be produced, for example, by stacking a positive electrode and a negative electrode with a separator interposed therebetween, rolling or folding the stack as necessary according to the battery shape, placing the stack in a battery container, injecting an electrolyte into the battery container, and sealing the container. In the nonaqueous secondary battery of the present invention, the above-described nonaqueous secondary battery electrode is used as at least one of the positive electrode and negative electrode, preferably the negative electrode. The nonaqueous secondary battery of the present invention may be provided with an overcurrent protection element such as a fuse or a PTC element, an expanded metal, a lead plate, or the like, as necessary to prevent internal pressure rise, overcharging / discharging, and the like within the secondary battery. The secondary battery may have any shape, such as a coin type, a button type, a sheet type, a cylindrical type, a rectangular type, or a flat type.

[0089] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. In the examples and comparative examples, the component fraction α of component A in the particulate polymer Ａ , component fraction α of B component Ｂ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２Ｂ The volume average particle diameter of the particulate polymer, the THF-insoluble fraction of the particulate polymer, the peel strength of the electrode (negative electrode), the peel strength of the electrode (negative electrode) during high-speed coating, the viscosity of the binder composition, the internal resistance of the lithium ion secondary battery, and the cycle characteristics of the lithium ion secondary battery were measured or evaluated by the following methods.

[0090] <Component fraction α of component A in particulate polymer Ａ , component fraction α of B componentＢ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２Ｂ <<Preparation of Sample for Pulse NMR Measurement>> The aqueous dispersions (binder compositions) of the particulate polymers obtained in the Examples and Comparative Examples were poured into glass petri dishes so that the dry film thickness would be about 1.0 mm, and dried for 3 days under conditions of 23°C x 50% RH. Thereafter, the resulting mixture was dried for 24 hours in a vacuum dryer to prepare samples for pulse NMR measurement.

[0091] <<Pulse NMR Measurement>> The pulse NMR measurement sample obtained above was chopped into approximately 2 mm square pieces, and the chopped pulse NMR measurement sample was filled into a 10 mm diameter glass sample tube (manufactured by Bruker, product number 1824511, 10 mm diameter, 180 mm length, flat bottom) to the extent that measurement with the pulse NMR device was possible. The sample tube was placed in a pulse NMR device (Bruker mq20), and measurement was performed using the solid echo method at 40°C under the following conditions: １ The free induction decay curve of the transverse relaxation of H was obtained. - Solid echo method - １ H resonance frequency: 20 MHz; Number of integration times: 512 times; Repetition time: 1 sec; FID observation time range: 200 μs

[0092] <<Component fraction α of component A Ａ , component fraction α of B component Ｂ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２Ｂ The obtained free induction decay curve y(t) was separated into two curves, A component and B component. The two curves were fitted with a Gaussian function for A component and an exponential function for B component. The following equation (1) was used for fitting: y(t) = A Ａ ×exp [-(t / T ２Ａ ) ２ ]+A Ｂ ×exp [-(t / T ２Ｂ ) )]...(1) In equation (1), y(t) is normalized based on its maximum value and ranges from 0 to 1. t is time. A Ａis the transverse relaxation time T in pulsed NMR measurement ２ is the intensity of the short A component at t = 0, A Ｂ is the transverse relaxation time T in pulsed NMR measurement ２ is the intensity of the long B component at t = 0, T ２Ａ is the transverse relaxation time of the A component, T ２Ｂ indicates the transverse relaxation time of the B component. The free induction decay curve was measured three times using the solid echo method. Ａ , A Ｂ , T ２Ａ , and T ２Ｂ The average values ​​of the strength A of the A component in the particulate polymer at t=0 are calculated. Ａ , B component intensity A at t = 0 Ｂ , the transverse relaxation time T of the A component ２Ａ , and the transverse relaxation time T of the B component ２Ｂ And then, "A Ａ / (A Ａ +A Ｂ ) × 100 [%]" is the component fraction α of component A Ａ Toshio, "A Ｂ / (A Ａ +A Ｂ ) × 100 [%]" is the component fraction α of component B Ｂ In addition, A Ａ , A Ｂ , T ２Ａ , and T ２Ｂ The calculation is obtained during pulsed NMR solid echo measurement. １ The data of the free induction decay curve of transverse relaxation of H was converted into a text file, which was read into Microsoft Excel spreadsheet software, and the approximate calculation function was used.

[0093] <Volume Average Particle Diameter of Particulate Polymer> The particle size distribution of the obtained binder composition (aqueous dispersion of particulate polymer, solid content adjusted to 0.1% by mass) was measured in accordance with JIS Z 8825 using a particle size distribution measuring device (manufactured by Shimadzu Corporation, product name "SALD-2300") using a laser diffraction scattering method as the measurement principle, and the particle diameter (D50) at which the cumulative volume calculated from the smallest diameter side became 50% in the measured particle size distribution was defined as the volume average particle diameter.

[0094] <THF-insoluble fraction of particulate polymer> The aqueous dispersions (binder compositions) of the particulate polymers obtained in the examples and comparative examples were dried in an environment of 50% humidity and 23 to 25°C temperature to form films with a thickness of 1±0.3 mm. The formed films were dried in a vacuum dryer at 60°C for 10 hours. Thereafter, the dried films were cut into 3 to 5 mm squares, and approximately 1 g was precisely weighed. The mass of the film pieces obtained by cutting was designated as w0. These film pieces were immersed in 50 g of tetrahydrofuran (THF) for 24 hours. Thereafter, the film pieces removed from the THF were vacuum-dried at 105°C for 3 hours, and the mass w1 of the insoluble matter was measured. The THF-insoluble fraction was then calculated using the following formula (2): THF-insoluble fraction (mass%) = (w1 / w0) × 100 (2)

[0095] <Peel Strength of Electrode (Negative Electrode)> The negative electrodes prepared in the Examples and Comparative Examples were cut into rectangular shapes measuring 100 mm in length and 10 mm in width to prepare test specimens. These test specimens were placed with the surface of the negative electrode composite layer facing downward, and cellophane tape was applied to the surface of the negative electrode composite layer. The cellophane tape used conformed to JIS Z1522 was used. The cellophane tape was fixed to a test table. One end of the current collector was then pulled vertically upward at a pulling rate of 50 mm / min to measure the stress when peeled off. This measurement was performed three times, and the average value was calculated. This average value was used as the peel strength and evaluated according to the following criteria: A: Peel strength of 10 N / m or more; B: Peel strength of 7 N / m or more but less than 10 N / m; C: Peel strength of less than 7 N / m.

[0096] <Peel strength of electrode (negative electrode) during high-speed coating> In the examples and comparative examples, the negative electrode slurry composition was applied to a copper foil having a thickness of 15 μm, which was a current collector, using a comma coater at a speed of 3.6 m / min until the weight per unit area after drying was 10.5 mg / cm. ２The copper foil coated with the negative electrode slurry composition was then dried by conveying it through an oven at 120°C for 20 seconds and an oven at 150°C for 20 seconds to obtain a negative electrode (negative electrode when coated at high speed). Using the obtained negative electrode when coated at high speed, the peel strength of the electrode (negative electrode) when coated at high speed was measured in the same manner as in the above "Peel strength of electrode (negative electrode)" and evaluated according to the following criteria. A: Peel strength when coated at high speed is 9 N / m or more B: Peel strength when coated at high speed is 6 N / m or more but less than 9 N / m C: Peel strength when coated at high speed is less than 6 N / m

[0097] <Viscosity of Binder Composition> After adjusting the solid content concentration of the binder compositions obtained in the Examples and Comparative Examples to 30% by mass, the viscosity of the binder composition was measured using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd., product name "TVB-10", rotation speed: 60 rpm), and evaluated according to the following criteria. The temperature during viscosity measurement was 25°C. If the viscosity of the binder composition is 10 mPa·s or more and 3000 mPa·s or less, it can be said that the binder composition has good viscosity. A: 10 mPa·s or more and 1500 mPa·s or less B: More than 1500 mPa·s and 3000 mPa·s or less C: Less than 10 mPa·s or more than 3000 mPa·s

[0098] <Internal Resistance of Lithium-Ion Secondary Battery> To evaluate the internal resistance of a lithium-ion secondary battery, the IV resistance was measured as follows. A conditioning treatment was performed in which the battery was charged at a charge rate of 0.1 C at a temperature of 25°C until the voltage reached 4.2 V, rested for 10 minutes, and then discharged at a constant current (CC) rate of 0.1 C to 3.0 V three times. The battery was then charged to 3.75 V at 1 C (C is a value expressed as rated capacity (mA) / 1 hour (h)) in a −10°C atmosphere, and then charged and discharged for 20 seconds at 0.5 C, 1.0 C, 1.5 C, and 2.0 C, centered on 3.75 V. For each case, the battery voltage after 15 seconds on the charging side was plotted against the current value, and the slope was determined as the IV resistance (Ω). The obtained IV resistance values ​​(Ω) were compared with the IV resistance of Comparative Example 1 and evaluated according to the following criteria. The smaller the IV resistance value, the lower the internal resistance of the secondary battery. A: Less than 85% of the IV resistance of Comparative Example 1 B: 85% or more and less than 95% of the IV resistance of Comparative Example 1 C: 95% or more and less than 105% of the IV resistance of Comparative Example 1 D: 105% or more of the IV resistance of Comparative Example 1

[0099] <Cycle Characteristics of Lithium-Ion Secondary Battery> After injecting the electrolyte, the lithium-ion secondary batteries prepared in the Examples and Comparative Examples were left to stand at 25°C for 5 hours. Next, they were charged to a cell voltage of 3.65 V at 25°C using a constant current method at 0.2 C, and then aged for 12 hours at 60°C. Then, they were discharged to a cell voltage of 3.00 V using a constant current method at 0.2 C at 25°C. Subsequently, they were subjected to constant current (CC)-constant voltage (CV) charging (upper limit cell voltage 4.20 V) using a constant current method at 0.2 C, and CC discharging to 3.00 V using a constant current method at 0.2 C. This 0.2 C charge-discharge cycle was repeated three times. Thereafter, 100 cycles of charge-discharge were performed in an environment at 25°C, with a cell voltage of 4.20-3.00 V and a charge-discharge rate of 1.0 C. The discharge capacity at the first cycle was defined as X1, and the discharge capacity at the 200th cycle as X2. Using the discharge capacities X1 and X2, the capacity change rate expressed as ΔC' = (X2 / X1) × 100 (%) was calculated and evaluated according to the following criteria. A larger value of the capacity change rate ΔC' indicates better cycle characteristics. A: ΔC' is 93% or more B: ΔC' is 90% or more but less than 93% C: ΔC' is 87% or more but less than 90% D: ΔC' is less than 87%

[0100] Example 1 Preparation of Aqueous Dispersion of Particulate Polymer (Binder Composition for Non-Aqueous Secondary Battery Negative Electrode) First, in the first stage of polymerization, a 5 MPa pressure vessel equipped with a stirrer was charged with 20 parts of styrene as an aromatic vinyl monomer for core formation, 72 parts of 1,3-butadiene as an aliphatic conjugated diene monomer, 1 part of methacrylic acid as a carboxylic acid group-containing monomer, 0.6 parts of alkyl diphenyl ether disulfonate as an emulsifier, 143 parts of ion-exchanged water, 0.1 parts of tert-dodecyl mercaptan as a chain transfer agent, and 0.3 parts of potassium persulfate as a polymerization initiator, and the mixture was thoroughly stirred. After heating to 55°C to initiate polymerization, the mixture was allowed to react for 10 hours. Next, the mixture was heated to 65°C and allowed to react for an additional 6 hours. Next, in the second stage polymerization, 4 parts of styrene as an aromatic vinyl monomer for forming the shell portion and 3 parts of methacrylic acid as a carboxylic acid group-containing monomer were added to the same pressure vessel under stirring, and the mixture was heated to 85°C and reacted for another 6 hours. Thereafter, unreacted monomers were removed by heating and vacuum distillation to obtain an aqueous dispersion of a particulate polymer as a binder composition. Using the obtained binder composition, the component fraction α of the A component of the particulate polymer was measured. Ａ , component fraction α of B component Ｂ , the transverse relaxation time T of the A component ２Ａ and the transverse relaxation time T of the B component ２Ｂ The volume average particle size of the particulate polymer, the THF-insoluble fraction of the particulate polymer, and the viscosity of the binder composition were measured or evaluated. The results are shown in Table 1.

[0101] <Preparation of Slurry Composition for Non-Aqueous Secondary Battery Negative Electrode> In a planetary mixer equipped with a disperser, artificial graphite (tap density: 0.85 g / cm 3 ) was added as a negative electrode active material. ３A mixture was obtained by adding 100 parts of a binder composition (capacity: 360 mAh / g), 1 part of carbon black (manufactured by TIMCAL, product name "Super C65") as a conductive material, and 1.2 parts of a 2% aqueous solution of carboxymethyl cellulose (manufactured by Daicel Corporation, product name "Daicel 2200") as a thickener, in terms of solid content. The resulting mixture was adjusted to a solid content of 60% with ion-exchanged water and then mixed at 25°C for 60 minutes. Next, the solid content was adjusted to 52% with ion-exchanged water, and then mixed for an additional 15 minutes at 25°C to obtain a mixed solution. 2.0 parts of the binder composition prepared above, in terms of solid content, and ion-exchanged water were added to the resulting mixed solution, and the final solid content was adjusted to 48%. After further mixing for 10 minutes, the mixture was degassed under reduced pressure to obtain a slurry composition for a negative electrode with good fluidity. The peel strength of the electrode (negative electrode) during high-speed coating was evaluated using the resulting slurry composition for a negative electrode.

[0102] <Formation of Negative Electrode> The obtained negative electrode slurry composition was coated on a copper foil having a thickness of 15 μm, which was a current collector, using a comma coater at a speed of 1.2 m / min so that the coating weight after drying was 10.5 mg / cm ２ The copper foil was dried by conveying it at a speed of 1.2 m / min through an oven at 120°C for 1 minute and then through an oven at 130°C for 1 minute. The obtained negative electrode blank was rolled using a roll press to reduce the density of the negative electrode composite layer to 1.70 g / cm. ３ The peel strength of the obtained negative electrode was evaluated. The results are shown in Table 1.

[0103] <Formation of Positive Electrode> LiCoO with a median diameter of 12 μm was used as the positive electrode active material. ２ 100 parts of the above, 2 parts of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd., product name "HS-100") as a conductive material, 2 parts of polyvinylidene fluoride (manufactured by Kureha Corporation, product name "#7208") as a binder, in terms of solid content, and N-methylpyrrolidone as a solvent were mixed to a total solids concentration of 70%. These were mixed using a planetary mixer to obtain a positive electrode slurry composition. The obtained positive electrode slurry composition was coated using a comma coater on a 20 μm thick aluminum foil current collector so that the basis weight after drying was 23 mg / cm２ The aluminum foil was then coated with the coating and dried so that the density of the positive electrode composite layer became 4.0 g / cm. This drying was performed by conveying the aluminum foil at a speed of 0.5 m / min through an oven at 60°C for 2 minutes. Thereafter, the aluminum foil was heat-treated at 120°C for 2 minutes to obtain a positive electrode blank. The positive electrode blank was then rolled with a roll press to obtain a positive electrode composite layer having a density of 4.0 g / cm. ３ A positive electrode of 1000 .mu.m was obtained.

[0104] <Preparation of Separator> A single-layer polypropylene separator (manufactured by Celgard, product name "Celgard 2500") was prepared as a separator made of a separator substrate. The polypropylene separator was a microporous polypropylene film having a thickness of 25 μm.

[0105] <Preparation of Lithium-Ion Secondary Battery> The pressed positive electrode and pressed negative electrode prepared as described above, and a separator were interposed in a separator / positive electrode / separator / negative electrode configuration to obtain a laminate. Next, the laminate of the electrode and separator was wound around a core with a diameter of 20 mm to obtain a wound body including a positive electrode, a separator, and a negative electrode. Subsequently, the obtained wound body was compressed in one direction at a speed of 10 mm / sec until it reached a thickness of 4.5 mm, thereby obtaining a flattened body. The obtained flattened body had an elliptical shape in a plan view, and the ratio of its major axis to its minor axis (major axis / minor axis) was 7.7. In addition, a nonaqueous electrolyte (LiPF with a concentration of 1.0 M) was added. ６ A solution (solvent): a mixed solvent of ethylene carbonate (EC) / ethyl methyl carbonate (EMC) = 3 / 7 (mass ratio), further containing 2 volume% vinylene carbonate (VC) as an additive) was prepared. Next, the flat body was housed in an aluminum laminate case together with the nonaqueous electrolyte solution. After connecting the negative and positive electrode leads to the designated locations, the opening of the laminate case was thermally sealed to produce a laminated lithium-ion secondary battery as a nonaqueous secondary battery. The resulting secondary battery was a pouch-shaped battery measuring 35 mm wide x 48 mm high x 5 mm thick, with a nominal capacity of 700 mAh. The resulting lithium-ion secondary battery was used to evaluate its internal resistance and cycle characteristics. The results are shown in Table 1.

[0106] (Example 2) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 22 parts, and the amount of styrene used in the second step was changed from 4 parts to 2 parts, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0107] (Example 3) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 18 parts, and the amount of styrene used in the second step was changed from 4 parts to 6 parts, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0108] (Example 4) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of 1,3-butadiene used in the first step was changed from 72 parts to 70 parts, and the amount of methacrylic acid used in the second step was changed from 3 parts to 5 parts, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0109] (Example 5) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 22 parts, and the amount of methacrylic acid used in the second step was changed from 3 parts to 1 part. Except for this, various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0110] (Example 6) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 32 parts, and the amount of 1,3-butadiene used was changed from 72 parts to 60 parts, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0111] (Example 7) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 11 parts, and the amount of 1,3-butadiene used was changed from 72 parts to 81 parts, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0112] (Example 8) In the preparation of an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), various operations, measurements, and evaluations were carried out in the same manner as in Example 1, except that 72 parts of 1,3-butadiene in the first step was changed to 72 parts of isoprene. The results are shown in Table 1.

[0113] (Example 9) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 21 parts, the amount of styrene used in the second step was changed from 4 parts to 2 parts, and 1 part of methacrylate as a (meth)acrylic acid ester monomer was further added in the second step, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0114] (Example 10) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 21 parts, the amount of styrene used in the second step was changed from 4 parts to 2 parts, and 1 part of acrylonitrile was further added as a vinyl cyanide monomer in the second step. Except for this, various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0115] (Example 11) In the preparation of an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the second step was changed from 4 parts to 2 parts, and 1 part of methacrylate as a (meth)acrylic acid ester monomer and 1 part of acrylonitrile as a vinyl cyanide monomer were further added in the second step, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0116] (Comparative Example 1) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 21 parts, the amount of 1,3-butadiene used from 72 parts to 73.5 parts, and the amount of methacrylic acid used in the second step was changed from 3 parts to 0.5 parts, except that the same operations, measurements, and evaluations were performed as in Example 1. The results are shown in Table 1.

[0117] (Comparative Example 2) In the preparation of an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 68 parts, and the amount of 1,3-butadiene used was changed from 72 parts to 24 parts, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0118] (Comparative Example 3) In the preparation of an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 21 parts, the amount of 1,3-butadiene used from 72 parts to 71 parts, and the amount of itaconic acid used in the second step was changed from 3 parts to 3 parts, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0119] (Comparative Example 4) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 21 parts, the amount of 1,3-butadiene used from 72 parts to 71 parts, and the amount of methacrylic acid used in the second step was changed from 3 parts to 3 parts acrylic acid, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0120] (Comparative Example 5) In preparing an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 14 parts, the amount of 1,3-butadiene used from 72 parts to 73 parts, and the amount of styrene used in the second step was changed from 4 parts to 9 parts, except that the same operations, measurements, and evaluations were carried out as in Example 1. The results are shown in Table 1.

[0121] (Comparative Example 6) In the preparation of an aqueous dispersion of a particulate polymer (binder composition for a non-aqueous secondary battery negative electrode), the amount of styrene used in the first step was changed from 20 parts to 24 parts, and no styrene was added in the second step, except that various operations, measurements, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0122] In Table 1, "St" represents styrene, "BD" represents 1,3-butadiene, "IP" represents isoprene, "MAA" represents methacrylic acid, "AA" represents acrylic acid, "IA" represents itaconic acid, "MMA" represents methyl methacrylate, and "AN" represents acrylonitrile.

[0123]

[0124] As is clear from Table 1, the binder compositions of Examples 1 to 11 can reduce the internal resistance of the resulting secondary battery compared to the binder compositions of Comparative Examples 1 to 5.

[0125] According to the present invention, a binder composition for a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a slurry composition for a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a non-aqueous secondary battery electrode that can reduce the internal resistance of a non-aqueous secondary battery can be provided. Furthermore, according to the present invention, a non-aqueous secondary battery with reduced internal resistance can be provided.

Claims

1. A binder composition for a non-aqueous secondary battery electrode, comprising a particulate polymer, wherein the particulate polymer is a polymer that is obtained during solid echo method measurement of pulsed NMR. １ The free induction decay curve of the transverse relaxation of H was calculated by the least squares method to obtain the transverse relaxation time T ２ When the waveform is separated into two curves derived from two components, A and B, in order of shortest, the component fraction α of the A component is Ａ The binder composition for a non-aqueous secondary battery electrode, 2. The transverse relaxation time T of the A component ２Ａ The binder composition for a non-aqueous secondary battery electrode according to claim 1, wherein the viscosity is 0.001 msec or more and 0.1 msec or less.

3. The binder composition for a non-aqueous secondary battery electrode according to claim 1, wherein the particulate polymer contains aromatic vinyl monomer units.

4. The binder composition for a non-aqueous secondary battery electrode according to claim 1, wherein the particulate polymer has a volume average particle size of 100 nm or more and 300 nm or less.

5. The binder composition for a non-aqueous secondary battery electrode according to claim 1, wherein the particulate polymer has an insoluble fraction in tetrahydrofuran of 70 mass % or more.

6. A slurry composition for a non-aqueous secondary battery electrode, comprising an electrode active material and the binder composition for a non-aqueous secondary battery electrode according to any one of claims 1 to 5.

7. A non-aqueous secondary battery electrode comprising an electrode mixture layer formed using the slurry composition for a non-aqueous secondary battery electrode according to claim 6.

8. A non-aqueous secondary battery comprising a positive electrode, a negative electrode, a separator and an electrolyte, wherein at least one of the positive electrode and the negative electrode is the electrode for a non-aqueous secondary battery according to claim 7.

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