WO2020240786A1

WO2020240786A1 - Slurry composition for batteries, and methods for producing electrode, electrolyte sheet, and battery member

Info

Publication number: WO2020240786A1
Application number: PCT/JP2019/021593
Authority: WO
Inventors: 拓也西村
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2020-12-03
Also published as: JP7438207B2; JPWO2020240786A1

Abstract

In one aspect, the present invention provides a slurry composition for batteries, the slurry composition containing a polymer; an ionic liquid; at least one electrolyte salt selected from the group consisting of lithium salts, sodium salts, calcium salts, and magnesium salts; and a dispersion medium, wherein the mass ratio of the total content of the polymer, the ionic liquid, and the electrolyte salt to the total content of the polymer, the ionic liquid, the electrolyte salt, and the dispersion medium is 0.1 to 0.3.

Description

A method for manufacturing a battery slurry composition, an electrode, an electrolyte sheet, and a battery member.

The present invention relates to a battery slurry composition and a method for manufacturing an electrode, an electrolyte sheet, and a battery member.

In recent years, with the spread of portable electronic devices, electric vehicles, etc., high-performance secondary batteries are required. Among them, the lithium secondary battery has a high energy density, and is therefore attracting attention as a power source for electric vehicle batteries, power storage batteries, and the like. Specifically, lithium secondary batteries as batteries for electric vehicles include zero-emission electric vehicles that do not have an engine, hybrid electric vehicles that have both an engine and a secondary battery, and plug-in hybrids that charge directly from the power system. It is used in electric vehicles such as electric vehicles. Further, a lithium secondary battery as a power storage battery is used in a stationary power storage system or the like that supplies power stored in advance in an emergency when the power system is cut off.

In order to use it in such a wide range of applications, a lithium secondary battery with a higher energy density is required, and its development is being made. In particular, lithium secondary batteries for electric vehicles are required to have high safety in addition to high input / output characteristics and high energy density, and therefore, more advanced technology for ensuring safety is required.

As a safer battery, the use of flame-retardant ionic liquid is being considered. For example, Patent Document 1 describes that a solvent obtained by mixing an organic electrolytic solution and an ionic liquid is used as the electrolytic solution, and flame retardancy can be ensured by mixing the organic electrolytic solution and the ionic liquid. It is disclosed.

As a method of improving the safety of the lithium secondary battery, a method of changing the electrolyte to a solid electrolyte is also known. For example, Patent Document 2 discloses a gel electrolyte containing a solvent such as a low molecular weight lipid peptide type gelling agent and a solvent such as an ionic liquid in order to provide an electrolyte having excellent ionic conductivity while immobilizing the electrolyte. There is.

Japanese Unexamined Patent Publication No. 2008-305574 Japanese Unexamined Patent Publication No. 2012-186055

However, according to the study by the present inventors, when an ionic liquid is used for the electrode mixture layer or the solid electrolyte layer, other components (for example, a polymer) which are poorly soluble in the ionic liquid are reprecipitated. It turned out that there are cases where it will be done. When the contained components are reprecipitated, it becomes difficult to form the electrode mixture layer or the electrolyte layer with a uniform thickness, which may adversely affect the battery characteristics.

It is an object of the present invention to provide a battery slurry composition capable of producing a battery member by coating on one side and suppressing reprecipitation of contained components.

The present invention contains, as a first aspect, a polymer, an ionic liquid, at least one electrolyte salt selected from the group consisting of lithium salt, sodium salt, calcium salt and magnesium salt, and a dispersion medium. Battery slurry composition in which the total mass ratio of the total content of the polymer, ionic liquid, and electrolyte salt to the total content of the polymer, ionic liquid, electrolyte salt, and dispersion medium is 0.1 to 0.3. Provide things.

The battery slurry composition may further contain an electrode active material. In this case, the mass ratio is preferably 0.2 to 0.3.

The battery slurry composition may further contain oxide particles. In this case, the mass ratio may be 0.13 to 0.3. The mass ratio may be 0.1 to 0.25.

The present invention is a method for manufacturing an electrode including a current collector and an electrode mixture layer formed on one surface of the current collector as a second aspect, and the manufacturing method is for the above-mentioned battery. Provided is a method for manufacturing an electrode, comprising a step of applying a slurry composition on one surface of a current collector to form an electrode mixture layer.

The present invention is a method for producing an electrolyte sheet comprising a base material and an electrolyte layer formed on one surface of the base material as a third aspect, wherein the above-mentioned battery slurry composition is used as a base material. Provided is a method for producing an electrolyte sheet, which comprises a step of applying the mixture on one surface to form an electrolyte layer.

The present invention is a method for manufacturing a battery member including a current collector, an electrode mixture layer, and an electrolyte layer in this order as a fourth aspect, and is an electrode mixture containing an electrode active material on one surface of the current collector. The step of forming the intermediate layer, the step of applying the above battery slurry composition on the surface of the electrode mixture intermediate layer opposite to the current collector, and the step of volatilizing the dispersion medium to volatilize the electrode mixture layer. And a step of forming an electrolyte layer, and a method of manufacturing a battery member.

According to one aspect of the present invention, it is possible to provide a battery slurry composition capable of producing a battery member by coating and suppressing reprecipitation of contained components.

It is a perspective view which shows the secondary battery which concerns on one Embodiment. It is an exploded perspective view which shows one Embodiment of the electrode group of the secondary battery shown in FIG. It is a schematic cross-sectional view which shows the manufacturing method of the positive electrode which concerns on one Embodiment. It is a schematic cross-sectional view which shows the manufacturing method of the electrolyte sheet which concerns on one Embodiment. It is a schematic cross-sectional view which shows the manufacturing method of the positive electrode member which concerns on one Embodiment. It is an exploded perspective view which shows one Embodiment of the electrode group of a bipolar type secondary battery.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including steps and the like) are not essential unless otherwise specified. The sizes of the components in each figure are conceptual, and the relative size relationships between the components are not limited to those shown in each figure.

The numerical values and their ranges in the present specification do not limit the present invention. The numerical range indicated by using "-" in the present specification indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value described in another stepwise description. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

In this specification, the following abbreviations may be used.
^{_{[FSI] -: N (SO}} 2 F) 2 -, bis (fluorosulfonyl) imide anion ^{_{[TFSI] -: N (SO}} 2 CF 3) 2 -, bis (trifluoromethanesulfonyl) imide anion ^[BOB] -: B _{_{_{_{(O 2 C 2 O 2)}}}} 2 -, bis oxalate borate anion ^{_{[f3C] -: C (SO}} 2 F) 3 -, tris (fluorosulfonyl) carbanions

In the present specification, the "positive electrode" and the "negative electrode" may be collectively referred to as an "electrode", and the same applies to similar expressions such as "electrode active material" and "electrode mixture layer".

FIG. 1 is a perspective view showing a secondary battery according to an embodiment. As shown in FIG. 1, the secondary battery 1 includes an electrode group 2 composed of a positive electrode, a negative electrode, and an electrolyte layer, and a bag-shaped battery exterior body 3 accommodating the electrode group 2. The positive electrode and the negative electrode are provided with a positive electrode current collecting tab 4 and a negative electrode current collecting tab 5, respectively. The positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 project from the inside of the battery exterior 3 to the outside so that the positive electrode and the negative electrode can be electrically connected to the outside of the secondary battery 1, respectively.

The battery exterior 3 may be formed of, for example, a laminated film. The laminated film may be, for example, a laminated film in which a resin film such as polyethylene terephthalate (PET) film, a metal foil such as aluminum, copper, and stainless steel, and a sealant layer such as polypropylene are laminated in this order.

FIG. 2 is an exploded perspective view showing an embodiment of the electrode group 2 of the secondary battery 1 shown in FIG. As shown in FIG. 2, the electrode group 2A includes a positive electrode 6, an electrolyte layer 7, and a negative electrode 8 in this order. The positive electrode 6 includes a positive electrode current collector 9 and a positive electrode mixture layer 10 provided on the positive electrode current collector 9. The positive electrode current collector 9 of the positive electrode 6 is provided with a positive electrode current collector tab 4. The negative electrode 8 includes a negative electrode current collector 11 and a negative electrode mixture layer 12 provided on the negative electrode current collector 11. The negative electrode current collector 11 of the negative electrode 8 is provided with a negative electrode current collector tab 5.

In one embodiment, it is considered that the electrode group 2A includes a first battery member (positive electrode member) including a positive electrode current collector 9, a positive electrode mixture layer 10, and an electrolyte layer 7 in this order. Can be done. Similarly, it can be seen that the electrode group 2A includes a second battery member (negative electrode member) including the negative electrode current collector 11, the negative electrode mixture layer 12, and the electrolyte layer 7 in this order. ..

The battery slurry composition in the present invention is, for example, a slurry composition used for producing an electrode, an electrolyte layer, or a battery member in a secondary battery as described above. In one embodiment, the battery slurry composition is a slurry composition (slurry composition) used for forming an electrode mixture layer (positive electrode mixture layer 10 or negative electrode mixture layer 12) included in an electrode (positive electrode 6 or negative electrode 8). Hereinafter, it is also referred to as “electrode mixture slurry”). The battery slurry composition is, in another embodiment, a slurry composition (hereinafter, also referred to as “electrolyte slurry”) used for forming the electrolyte layer 7.

The battery slurry composition according to one embodiment contains a polymer, an ionic liquid, at least one electrolyte salt selected from the group consisting of lithium salt, sodium salt, calcium salt and magnesium salt, and a dispersion medium. To do.

The polymer is a polymer containing at least one selected from the group consisting of ethylene tetrafluoride, vinylidene fluoride, hexafluoropropylene, acrylic acid, maleic acid, ethyl methacrylate, methyl methacrylate, and acrylonitrile as a monomer unit, styrene-butadiene. It may be rubber, isopene rubber, rubber such as acrylic rubber, or the like. The polymer is preferably a polymer containing at least one selected from the group consisting of polyvinylidene fluoride, hexafluoropropylene, and vinylidene fluoride as a monoma unit.

In the electrode mixture slurry, the polymer is preferably polyvinylidene fluoride or a copolymer containing hexafluoropropylene and vinylidene fluoride as structural units. The polymer in the electrode mixture slurry has a role as a binder.

In the electrolyte slurry, the polymer preferably has a first structural unit selected from the group consisting of ethylene tetrafluoroethylene and vinylidene fluoride.

The polymer in the electrolyte slurry is preferably one kind or two or more kinds of polymers, and among the structural units constituting one kind or two or more kinds of polymers, the above-mentioned first structural unit and hexafluoropropylene are included. , Acrylic acid, maleic acid, ethyl methacrylate, and a second structural unit selected from the group consisting of methyl methacrylate. That is, the first structural unit and the second structural unit may be contained in one kind of polymer to form a copolymer, and each of them is contained in another polymer and has a first structural unit. And a second polymer having a second structural unit may constitute at least two kinds of polymers.

More specifically, the polymer contained in the electrolyte slurry may be polytetrafluoroethylene, polyvinylidene fluoride, copolymer of vinylidene fluoride and hexafluoropropylene, or the like.

The polymer content is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.5% by mass or more, based on the total amount of the battery slurry composition, from the viewpoint of facilitating application of the battery slurry composition. It is 0.7% by mass or more. The polymer content is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 30% by mass or less, based on the total amount of the battery slurry composition, from the viewpoint of more preferably suppressing reprecipitation in the battery slurry composition. It is 20% by mass or less.

When the battery slurry composition is an electrode mixture slurry, the content of the polymer is preferably 0.3% by mass or more based on the total amount of the electrode mixture slurry from the viewpoint of making it easier to apply the electrode mixture slurry. It is more preferably 0.5% by mass or more, still more preferably 0.7% by mass or more. The polymer content is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5 based on the total amount of the electrode mixture slurry from the viewpoint of more preferably suppressing reprecipitation from the electrode mixture slurry. It is mass% or less.

The content of the polymer is 0.3% by mass or more, 0.5% by mass or more, 1 by mass or more, based on the total amount of the non-volatile content (the component excluding the dispersion medium from the electrode mixture slurry, the same applies hereinafter) in the electrode mixture slurry. It may be 10% by mass or more, 1.5% by mass or more, and may be 10% by mass or less, 8% by mass or less, 6% by mass or less, or 4% by mass or less. As a result, the content of the polymer in the obtained electrode mixture layer becomes the same as the content.

When the battery slurry composition is an electrolyte slurry, the content of the polymer is preferably 1% by mass or more, more preferably 3% by mass or more, based on the total amount of the electrolyte slurry from the viewpoint that the electrolyte slurry can be applied more uniformly. More preferably, it is 5% by mass or more. The polymer content is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, based on the total amount of the electrolyte slurry, from the viewpoint of more preferably suppressing reprecipitation in the electrolyte slurry. ..

The content of the polymer is 3% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass based on the total amount of the non-volatile content (the component excluding the dispersion medium from the electrolyte slurry, the same applies hereinafter) in the electrolyte slurry. It may be 70% by mass or less, 60% by mass or less, 50% by mass or less, or 40% by mass or less. As a result, the content of the polymer in the obtained electrolyte layer becomes the same as the content.

The ionic liquid contains the following anionic and cationic components. The ionic liquid in the present specification is a substance that is liquid at −20 ° C. or higher.

Anion component of the ionic liquid is not particularly ^{^{limited, Cl -, Br -, I}} - and a halogen _{^{_{_{anion, BF 4 -, N (SO}}}} 2 F) 2 - ([FSI] -) inorganic anions such as, B _{_{_{^{(C 6 H 5) 4 -}}}} , CH 3 SO 2 O -, CF 3 SO 2 O -, N (SO 2 C 4 F 9) 2 -, N (SO 2 CF 3) 2 - ([TFSI] -) , N (SO ₂ C ₂ F ₅ ) ₂ ^- etc. Organic anions may be used. The anionic component of the ionic liquid preferably contains at least one of the anionic components represented by the following formula (1).
N (SO ₂ C _m F _{2 m + 1} ) (SO ₂ C _n F _{2n + 1} ) ^- (1)
[In the formula, m and n each independently represent an integer of 0 to 5. m and n may be the same or different from each other, and are preferably the same as each other. ]

Anion component represented by formula (1) may, for _{_{_{_{^{example, N (SO 2 C 4 F}}}}} 9) 2 -, N (SO 2 F) 2 -, N (SO 2 CF 3) 2 - and N _(SO 2 C _₂ F ₅₎ ₂ ^- a. Anion component of the ionic liquid, from the viewpoint of improving the ion conductivity of the secondary battery 1, and more _{_{_{_{^{preferably, N (SO 2 C 4 F}}}}} 9) 2 -, CF 3 SO 2 O -, N (SO 2 F) _{^{_{_{2 -, N (SO 2 CF}}}} 3) 2 -, and _{_{_{N (SO 2 C 2 F 5}}} ) 2 - contains at least one selected from the group consisting of, more preferably _{N (SO} _{2 F)} 2 ^- a contains.

The cation component of the ionic liquid is preferably at least one selected from the group consisting of a chain quaternary onium cation, a piperidinium cation, a pyrrolidinium cation, a pyridinium cation, and an imidazolium cation.

The chain quaternary onium cation is, for example, a compound represented by the following formula (2).

[In the formula, R ¹ to R ⁴ are independently chain alkyl groups having 1 to 20 carbon atoms or chain alkoxyalkyl groups represented by RO- (CH ₂ ) _n- (R is It represents a methyl group or an ethyl group, where n represents an integer of 1 to 4), and X represents a nitrogen atom or a phosphorus atom. The number of carbon atoms of the alkyl group represented by R ¹ to R ⁴ is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. ]

The piperidinium cation is, for example, a nitrogen-containing six-membered cyclic compound represented by the following formula (3).

[In the formula, R ⁵ and R ⁶ are each independently an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group represented by RO-O- (CH ₂ ) _n- (R is a methyl group or ethyl). Represents a group, where n represents an integer of 1 to 4). The number of carbon atoms of the alkyl group represented by R ⁵ and R ⁶ is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. ]

The pyrrolidinium cation is, for example, a five-membered cyclic compound represented by the following formula (4).

[In the formula, R ⁷ and R ⁸ are each independently an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group represented by RO-O- (CH ₂ ) _n- (R is a methyl group or ethyl). Represents a group, where n represents an integer of 1 to 4). The alkyl group represented by R ⁷ and R ⁸ has preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. ]

The pyridinium cation is, for example, a compound represented by the following formula (5).

[In the formula, R ⁹ to R ¹³ are independently alkyl groups having 1 to 20 carbon atoms and alkoxyalkyl groups represented by RO-O- (CH ₂ ) _n- (R is a methyl group or an ethyl group). , N represents an integer of 1 to 4), or represents a hydrogen atom. The number of carbon atoms of the alkyl group represented by R ⁹ to R ¹³ is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. ]

The imidazolium cation is, for example, a compound represented by the following formula (6).

[In the formula, R ¹⁴ to R ¹⁸ are independently alkyl groups having 1 to 20 carbon atoms and alkoxyalkyl groups represented by RO-O- (CH ₂ ) _n- (R is a methyl group or an ethyl group). , N represents an integer of 1 to 4), or represents a hydrogen atom. The number of carbon atoms of the alkyl group represented by R ¹⁴ to R ¹⁸ is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. ]

More specifically, the ionic liquid is N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium-bis (trifluoromethanesulfonyl) imide (DEME-TFSI), N, N-diethyl-N. -Methyl-N- (2-methoxyethyl) ammonium-bis (fluorosulfonyl) imide (DEME-FSI), 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide (EMI-TFSI), 1- Ethyl-3-methylimidazolium-bis (fluorosulfonyl) imide (EMI-FSI), N-methyl-N-propylpyrrolidinium-bis (trifluoromethanesulfonyl) imide (Py13-TFSI), N-methyl-N- Propropylpyrrolidinium-bis (fluorosulfonyl) imide (Py13-FSI), N-ethyl-N-methylpyrrolidinium-bis (trifluoromethanesulfonyl) imide (Py12-TFSI), N-ethyl-N-methylpyrrolidi It may be nium-bis (fluorosulfonyl) imide (Py12-FSI), 1-ethyl-3-methylimidazolium disianamide (EMI-DCA) or the like. These may be used individually by 1 type or in combination of 2 or more type.

The electrolyte salt is at least one selected from the group consisting of lithium salt, sodium salt, calcium salt, and magnesium salt.

Anionic component of the electrolyte salt, a halide ion ^{^{(I -, Cl -, Br}} - , ^{_{^{_{_{etc.), SCN -, BF 4 -}}}}} , BF 3 (CF 3) -, BF 3 (C 2 F 5) -, PF 6 - _{^{_{^{_{, ClO 4 -, SbF 6 -}}}}} , N (SO 2 F) 2 -, N (SO 2 CF 3) 2 -, N (SO 2 C 2 F 5) 2 -, B (C 6 H 5) 4 -, _{_{_{_{B (O 2 C 2 H 4}}}} ) 2 -, C (SO 2 F) 3 -, C (SO 2 CF 3) 3 -, CF 3 COO -, CF 3 SO 2 O -, C 6 F 5 SO 2 O ^- , B (O ₂ C ₂ O ₂ ) ₂ ^- etc. Anionic component of the electrolyte salt, _{_{^{preferably, N (SO 2 F) 2}}} -, N (SO 2 CF 3) 2 - above anion component represented by formula (1), such _as, ^PF 6 -, BF ₄ ^- _{_{_{, B (O 2 C 2 O}}} 2) 2 -, or ClO ₄ ^- is.

Lithium salts include LiPF ₆ , LiBF ₄ , Li [FSI], Li [TFSI], Li [f3C], Li [BOB], LiClO ₄ , LiBF ₃ (CF ₃ ), LiBF ₃ (C ₂ F ₅ ), LiBF. ₃ (C ₃ F ₇ ), LiBF ₃ (C ₄ F ₉ ), LiC (SO ₂ CF ₃ ) ₃ , LiCF ₃ SO ₂ O, LiCF ₃ COO, and LiRCOO (R is an alkyl group having 1 to 4 carbon atoms). , A phenyl group, or a naphthyl group), which may be at least one selected from the group.

Sodium salts include NaPF ₆ , NaBF ₄ , Na [FSI], Na [TFSI], Na [f3C], Na [BOB], NaClO ₄ , NaBF ₃ (CF ₃ ), NaBF ₃ (C ₂ F ₅ ), NaBF. ₃ (C ₃ F ₇ ), NaBF ₃ (C ₄ F ₉ ), NaC (SO ₂ CF ₃ ) ₃ , NaCF ₃ SO ₂ O, NaCF ₃ COO, and NaRCOO (R is an alkyl group having 1 to 4 carbon atoms). , A phenyl group, or a naphthyl group), which may be at least one selected from the group.

Calcium salts are Ca (PF ₆ ) ₂ , Ca (BF ₄ ) ₂ , Ca [FSI] ₂ , Ca [TFSI] ₂ , Ca [f3C] ₂ , Ca [BOB] ₂ , Ca (ClO ₄ ) ₂ , Ca. [BF ₃ (CF ₃ )] ₂ , Ca [BF ₃ (C ₂ F ₅ )] ₂ , Ca [BF ₃ (C ₃ F ₇ )] ₂ , Ca [BF ₃ (C ₄ F ₉ )] ₂ , Ca [C (SO ₂ CF ₃ ) ₃ ] ₂ , Ca (CF ₃ SO ₂ O) ₂ , Ca (CF ₃ COO) ₂ , and Ca (RCOO) ₂ (R is an alkyl group having 1 to 4 carbon atoms, phenyl. It may be at least one selected from the group consisting of a group or a naphthyl group).

Magnesium salts are Mg (PF ₆ ) ₂ , Mg (BF ₄ ) ₂ , Mg [FSI] ₂ , Mg [TFSI] ₂ , Mg [f3C] ₂ , Mg [BOB] ₂ , Mg (ClO ₄ ) ₂ , Mg. [BF ₃ (CF ₃ )] ₂ , Mg [BF ₃ (C ₂ F ₅ )] ₂ , Mg [BF ₃ (C ₃ F ₇ )] ₂ , Mg [BF ₃ (C ₄ F ₉ )] ₂ , Mg [C (SO ₂ CF ₃ ) ₃ ] ₂ , Mg (CF ₃ SO ₃ ) ₂ , Mg (CF ₃ COO) ₂ , and Mg (RCOO) ₂ (R is an alkyl group or phenyl group having 1 to 4 carbon atoms. , Or a naphthyl group), which may be at least one selected from the group.

Of these, from the viewpoint of dissociability and electrochemical stability, the electrolyte salt is preferably LiPF ₆ , LiBF ₄ , Li [FSI], Li [TFSI], Li [f3C], Li [BOB], LiClO ₄ , LiBF ₃ (CF ₃ ), LiBF ₃ (C ₂ F ₅ ), LiBF ₃ (C ₃ F ₇ ), LiBF ₃ (C ₄ F ₉ ), LiC (SO ₂ CF ₃ ) ₃ , LiCF ₃ SO ₂ O, It is at least one selected from the group consisting of LiCF ₃ COO and LiRCOO (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group), and more preferably Li [TFSI], Li. It is at least one selected from the group consisting of [FSI], LiPF ₆ , LiBF ₄ , Li [BOB], and LiClO ₄ , and more preferably 1 selected from the group consisting of Li [TFSI] and Li [FSI]. It is a seed.

The ionic liquid and the electrolyte salt may be contained in the battery slurry composition as the ionic liquid electrolyte. The ionic liquid electrolyte is a liquid in which an electrolyte salt is dissolved in an ionic liquid.

In the ionic liquid electrolytic solution, the salt concentration of the electrolyte salt per unit volume of the ionic liquid may be 0.3 mol / L or more, 0.5 mol / L or more, or 1.0 mol / L or more, and may be 3.0 mol / L or more. It may be L or less, 2.7 mol / L or less, or 2.5 mol / L or less.

The content of the ionic liquid electrolyte (the total content of the ionic liquid and the electrolyte salt) is preferably 1% by mass or more based on the total amount of the battery slurry composition from the viewpoint of improving the ionic conductivity of the secondary battery 1. , More preferably 3% by mass or more, still more preferably 5% by mass or more. The content of the ionic liquid electrolytic solution is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total amount of the battery slurry composition, from the viewpoint of more preferably suppressing reprecipitation in the battery slurry composition. More preferably, it is 20% by mass or less.

When the battery slurry composition is an electrode mixture slurry, the content of the ionic liquid electrolytic solution is preferably 1% by mass based on the total amount of the electrode mixture slurry from the viewpoint of improving the ionic conductivity of the electrode mixture layer. As mentioned above, it is more preferably 3% by mass or more, still more preferably 5% by mass or more. The content of the ionic liquid electrolytic solution is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 20% by mass or less, based on the total amount of the electrode mixture slurry, from the viewpoint of more preferably suppressing reprecipitation in the electrode mixture slurry. Is 15% by mass or less.

The content of the ionic liquid electrolytic solution is preferably 3% by mass or more, more preferably 5% by mass or more, based on the total amount of the non-volatile content in the electrode mixture slurry from the viewpoint of improving the ionic conductivity of the electrode mixture layer. , More preferably 10% by mass or more. The content of the ionic liquid electrolytic solution is preferably 30% by mass or less, more preferably 30% by mass or less, based on the total amount of the non-volatile content in the electrode mixture slurry from the viewpoint of more preferably suppressing reprecipitation in the electrode mixture slurry. It is 25% by mass or less, more preferably 20% by mass or less. As a result, the content of the ionic liquid electrolytic solution in the obtained electrode mixture layer becomes the same as the content.

When the battery slurry composition is an electrolyte slurry, the content of the ionic liquid electrolyte is preferably 0.5% by mass or more based on the total amount of the battery slurry composition from the viewpoint of improving the ionic conductivity of the electrolyte layer. , More preferably 1% by mass or more, still more preferably 1.5% by mass or more. The content of the ionic liquid electrolyte is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 30% by mass or less, based on the total amount of the battery slurry composition, from the viewpoint of more preferably suppressing reprecipitation in the electrolyte slurry. It is 20% by mass or less.

The content of the ionic liquid electrolytic solution may be 3% by mass or more, 5% by mass or more, 5% by mass or more, 10% by mass or more, or 20% by mass or more, based on the total amount of the non-volatile content in the electrolyte slurry. Further, it may be 60% by mass or less, 50% by mass or less, or 40% by mass or less. As a result, the content of the ionic liquid electrolytic solution in the obtained electrolyte layer becomes the same as the content.

The dispersion medium may be water or an organic solvent. The organic solvent may be N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylacetamide, methyl ethyl ketone, toluene, 2-butanol, cyclohexanone, ethyl acetate, 2-propanol and the like. It is preferably NMP or DMSO. As the dispersion medium, these may be used alone or in combination of two or more.

The content of the dispersion medium is based on the total amount of the battery slurry composition, preferably 3% by mass or more, 5% by mass or more, 10% by mass or more, and 20% by mass from the viewpoint of facilitating the application of the battery slurry composition. As mentioned above, it is 30% by mass or more, 40% by mass or more, or 50% by mass or more. The content of the dispersion medium is preferably 90% by mass or less, 70% by mass or less, and 50% by mass or less based on the total amount of the battery slurry composition from the viewpoint of more preferably suppressing reprecipitation in the battery slurry composition. , Or 40% by mass or less.

When the battery slurry composition is an electrode mixture slurry, the content of the dispersion medium is preferably 3% by mass or more based on the total amount of the electrode mixture slurry from the viewpoint of making it easier to apply the electrode mixture slurry. It is preferably 5% by mass or more, and more preferably 10% by mass or more. The content of the dispersion medium is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 50% by mass or less, based on the total amount of the electrode mixture slurry, from the viewpoint of more preferably suppressing reprecipitation from the electrode mixture slurry. It is 40% by mass or less.

The content of the dispersion medium may be 3 parts by mass or more, 5 parts by mass or more, 10 parts by mass or more, or 20 parts by mass or more with respect to 100 parts by mass of the non-volatile content in the electrode mixture slurry, and 1000 parts by mass. It may be parts by mass or less, 500 parts by mass or less, 300 parts by mass or less, 100 parts by mass or less, or 50 parts by mass or less.

When the battery slurry composition is an electrolyte slurry, the content of the dispersion medium is preferably 20% by mass or more, more preferably 30% by mass or more based on the total amount of the electrolyte slurry from the viewpoint that the electrolyte slurry can be applied more uniformly. , More preferably 40% by mass or more. The content of the dispersion medium is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, based on the total amount of the electrolyte slurry, from the viewpoint of more preferably suppressing reprecipitation in the electrolyte slurry. is there.

The content of the dispersion medium may be 10 parts by mass or more, 25 parts by mass or more, or 50 parts by mass or more, and 1000 parts by mass or less and 500 parts by mass with respect to 100 parts by mass of the non-volatile content in the electrolyte slurry. Below, or 300 parts by mass or less.

When the battery slurry composition is an electrode mixture slurry, the electrode mixture slurry may contain an electrode active material. That is, the electrode mixture slurry may contain a polymer, an ionic liquid, an electrolyte salt, a dispersion medium, and an electrode active material.

When the electrode is a positive electrode, the electrode mixture slurry (positive electrode mixture slurry) may contain a positive electrode active material. The positive electrode active material may be a lithium transition metal compound such as a lithium transition metal oxide or a lithium transition metal phosphate.

The lithium transition metal oxide may be, for example, lithium manganate, lithium nickel oxide, lithium cobalt oxide, or the like. The lithium transition metal oxide is a part of transition metals such as Mn, Ni, and Co contained in lithium manganate, lithium nickelate, lithium cobalt, etc., and one or more other transition metals, or It may be a lithium transition metal oxide substituted with a metal element (typical element) such as Mg or Al. That is, the lithium transition metal oxide may be a compound represented by ^LiM 1 _{O 2} or ^LiM _¹ 2 _O 4 ^(M ₁ comprises at least one transition metal). Specifically, the lithium transition metal oxides are Li (Co _1/3 Ni _1/3 Mn _1/3 ) O ₂ , LiNi _1/2 Mn _1/2 O ₂ , and LiNi _1/2 Mn _3/2 O. It may be ₄ mag.

The lithium transition metal oxide is preferably a compound represented by the following formula (A) from the viewpoint of further improving the energy density.
Li _a Ni _b Co _c M ² _d O _{2 + e} (A)
[In the formula, M ² is at least one selected from the group consisting of Al, Mn, Mg and Ca, and a, b, c, d and e are 0.2 ≦ a ≦ 1.2 and 0, respectively. .5 ≦ b ≦ 0.9, 0.1 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, −0.2 ≦ e ≦ 0.2, and b + c + d = 1. ]

Lithium transition metal phosphates are LiFePO ₄ , LiMnPO ₄ , LiMn _x M ³ _1-x PO ₄ (0.3 ≤ x ≤ 1, M ³ are Fe, Ni, Co, Ti, Cu, Zn, Mg and Zr. It may be at least one element selected from the group consisting of) and the like.

The positive electrode active material may be primary particles that have not been granulated, or may be secondary particles that have been granulated.

The particle size of the positive electrode active material is adjusted so as to be equal to or less than the thickness of the positive electrode mixture layer 10. When there are coarse particles having a particle size equal to or larger than the thickness of the positive electrode mixture layer 10 in the positive electrode active material, the coarse particles are removed in advance by sieving classification, wind flow classification, etc. A positive electrode active material having a diameter is selected.

The average particle size of the positive electrode active material is preferably 0.1 μm or more, and more preferably 1 μm or more. The average particle size of the positive electrode active material is preferably 30 μm or less, more preferably 25 μm or less. The average particle size of the positive electrode active material is the particle size (D ₅₀ ) when the ratio (volume fraction) to the volume of the entire positive electrode active material is 50%. For the average particle size (D ₅₀ ) of the positive electrode active material, a suspension in which the positive electrode active material is suspended in water is measured by a laser scattering method using a laser scattering type particle size measuring device (for example, Microtrac). You can get it.

The content of the positive electrode active material may be 20% by mass or more, 30% by mass or more, or 40% by mass or more based on the total amount of the positive electrode mixture slurry, and 80% by mass or less, 70% by mass or less, or 60. It may be mass% or less.

The content of the positive electrode active material may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and 99% by mass, based on the total amount of the non-volatile content in the positive electrode mixture slurry. It may be less than or equal to%. As a result, the content of the positive electrode active material in the obtained positive electrode mixture layer becomes the same as the content.

When the electrode is a negative electrode, the electrode mixture slurry (negative electrode mixture slurry) may contain a negative electrode active material. As the negative electrode active material, those commonly used in the field of energy devices can be used. Specific examples of the negative electrode active material include metallic lithium, lithium titanate (Li ₄ Ti ₅ O ₁₂ ), lithium alloys or other metal compounds, carbon materials, metal complexes, and organic polymer compounds. .. The negative electrode active material may be one of these alone or a mixture of two or more of them. Examples of carbon materials include natural graphite (scaly graphite, etc.), graphite such as artificial graphite (graphite), amorphous carbon, carbon fiber, and acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal. Examples include carbon black such as black. The negative electrode active material may be silicon, tin or a compound containing these elements (alloy with oxide, nitride, other metal) from the viewpoint of obtaining a larger theoretical capacity (for example, 500 to 1500 Ah / kg). Good.

The average particle size (D ₅₀ ) of the negative electrode active material is preferably 1 μm or more from the viewpoint of obtaining a well-balanced negative electrode having an enhanced ability to retain electrolyte salts while suppressing an increase in irreversible capacity due to a decrease in particle size. It is more preferably 5 μm or more, further preferably 10 μm or more, preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less. The average particle size (D ₅₀ ) of the negative electrode active material is measured by the same method as the average particle size (D ₅₀ ) of the positive electrode active material described above.

The content of the negative electrode active material may be 20% by mass or more, 30% by mass or more, or 40% by mass or more based on the total amount of the negative electrode mixture slurry, and 80% by mass or less, 70% by mass or less, or 60. It may be mass% or less.

The content of the negative electrode active material is 50% by mass or more, 55% by mass or more, or 60% by mass or more based on the total amount of non-volatile components (components obtained by removing the dispersion medium from the negative electrode mixture slurry) in the negative electrode mixture slurry. It may be 99% by mass or less, 95% by mass or less, or 90% by mass or less. As a result, the content of the negative electrode active material in the obtained negative electrode mixture layer becomes the same as the content.

When the battery slurry composition is an electrode mixture slurry, the electrode mixture slurry may contain a conductive material. The conductive material is not particularly limited, but may be a carbon material such as graphite, acetylene black, carbon black, or carbon fiber. As the conductive material, these may be used alone or in combination of two or more.

The content of the conductive material may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, and 10% by mass or less and 5% by mass based on the total amount of the electrode mixture slurry. % Or less, or 3% by mass or less.

The content of the conductive material may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, and is 20% by mass, based on the total amount of the non-volatile content in the electrode mixture slurry. % Or less, 10% by mass or less, or 5% by mass or less. As a result, the content of the conductive material in the obtained electrode mixture layer becomes the same as the content.

When the battery slurry composition is an electrolyte slurry, the electrolyte slurry may contain oxide particles. That is, the electrolyte slurry may contain a polymer, an ionic liquid, an electrolyte salt, a dispersion medium, and oxide particles.

The oxide particles are, for example, inorganic oxide particles. The inorganic oxide is, for example, an inorganic oxide containing Li, Mg, Al, Si, Ca, Ti, Zr, La, Na, K, Ba, Sr, V, Nb, B, Ge and the like as constituent elements. Good. The oxide particles are preferably at least one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , AlOOH, MgO, CaO, ZrO ₂ , TiO ₂ , Li ₇ La ₃ Zr ₂ O ₁₂ , and BaTIO ₃ . It is a particle. Since the oxide particles have polarity, the dissociation of the electrolyte in the electrolyte layer can be promoted and the battery characteristics can be enhanced.

The oxide particles may be oxides of rare earth metals. The oxide particles are specifically scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, placeodium oxide, neodymium oxide, samarium oxide, urobium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, formium oxide, erbium oxide, and oxidation. It may be thulium, ytterbium oxide, lutetium oxide or the like.

The oxide particles may have a hydrophobic surface. Oxide particles usually have a hydroxyl group on their surface and tend to be hydrophilic. Oxide particles having a hydrophobic surface have fewer hydroxyl groups on the surface than oxide particles having no hydrophobic surface. Therefore, the use of oxide particles having a hydrophobic surface, if it contains the ionic liquid in the electrolyte slurry (e.g., the anionic component is _N _(SO ² F) ² - having like _{_{^{-, N (SO 2 CF 3}}} ) 2 Since the ionic liquid) and the ionic liquid are hydrophobic, it is expected that the affinity between the oxide particles and the ionic liquid will be improved. Therefore, it is considered that the liquid retention property of the ionic liquid in the electrolyte layer 7 is further improved, and as a result, the ionic conductivity of the electrolyte layer 7 is improved. Further, in a secondary battery including an electrolyte layer 7 containing oxide particles having a hydrophobic surface, the discharge characteristics can be particularly improved.

Oxide particles having a hydrophobic surface can be obtained, for example, by treating oxide particles exhibiting hydrophilicity with a surface treatment agent capable of imparting a hydrophobic surface. That is, the oxide particles having a hydrophobic surface mean the oxide particles surface-treated with a surface treatment agent. The surface treatment agent is preferably a silicon-containing compound.

The oxide particles may be surface-treated with a silicon-containing compound. That is, the oxide particles may be those in which the surface of the oxide particles and the silicon atom of the silicon-containing compound are bonded via an oxygen atom. The silicon-containing compound is preferably at least one selected from the group consisting of halogen-containing alkylsilanes, alkoxysilanes, epoxy group-containing silanes, amino group-containing silanes, silazanes, and siloxanes.

The halogen element in the halogen-containing alkylsilane may be chlorine, fluorine, or the like. The halogen-containing alkylsilane (alkylchlorosilane) containing chlorine may be methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, n-octyldimethylchlorosilane or the like. The halogen-containing alkylsilane (fluoroalkylsilane) containing fluorine may be trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, or the like.

The alkoxysilanes are methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydiphenylsilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, tetraethoxysilane, methyltriethoxysilane, and dimethyldiphenyl. It may be ethoxysilane, n-propyltriethoxysilane, or the like.

The epoxy group-containing silanes are 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxy. It may be silane, 3-glycidoxypropyltriethoxysilane, or the like.

Amino group-containing silanes are N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- It may be phenyl-3-aminopropyltrimethoxysilane or the like.

Cilazan may be hexamethyldisilazan or the like. The siloxane may be dimethyl silicone oil or the like. Those having a reactive functional group (for example, a carboxyl group) at one end or both ends thereof may be used.

As the oxide particles having a hydrophobic surface (surface-treated oxide particles), those produced by a known method may be used, or commercially available products may be used as they are.

Oxide particles are generally a primary particle (a particle that does not constitute a secondary particle) that integrally forms a single particle and a plurality of primary particles, judging from the apparent geometrical morphology. May include secondary particles formed by the aggregation of.

The specific surface area of the oxide particles may be 2 to 500 m ² / g, 2 to 400 m ² / g, 5 to 100 m ² / g, 10 to 80 m ² / g, or 15 to 60 m ² / g. May be good. When the specific surface area is 2 to 500 m ² / g, the secondary battery provided with the electrolyte layer containing such oxide particles tends to have excellent discharge characteristics. From the same viewpoint, the specific surface area of the oxide particles may be 2 m ² / g or more, 5 m ² / g or more, 10 m ² / g or more, 15 m ² / g or more, or 50 m ² / g or more, and may be 500 m. ² / g or less, 400m ² / g or less, 350m ² / g or less, 300m ² / g or less, 200m ² / g or less, 100m ² / g or less, 90m ² / g or less, 80m ² / g or less, or 60m ² It may be less than / g. The specific surface area of the oxide particles means the specific surface area of the entire oxide particles including the primary particles and the secondary particles, and is measured by the BET method.

The average primary particle size of the oxide particles (average particle size of the primary particles) is preferably 0.005 μm (5 nm) or more, more preferably 0.01 μm (from the viewpoint of improving the conductivity of the secondary battery 1). It is 10 nm) or more, and more preferably 0.015 μm (15 nm) or more. The average primary particle size of the oxide particles is preferably 1 μm or less, more preferably 0.1 μm or less, and further preferably 0.05 μm or less from the viewpoint of thinning the electrolyte layer 7. The average primary particle size of the oxide particles can be measured by observing the oxide particles with a transmission electron microscope or the like.

The average particle size of the oxide particles is preferably 0.005 μm or more, more preferably 0.01 μm or more, and further preferably 0.03 μm or more. The average particle size of the oxide particles is preferably 5 μm or less, more preferably 3 μm or less, and further preferably 1 μm or less. The average particle size of the oxide particles is measured by the laser diffraction method, and corresponds to the particle size at which the volume accumulation is 50% when the volume cumulative particle size distribution curve is drawn from the small particle size side.

The content of the oxide particles may be 0.5% by mass or more, 1% by mass or more, or 3% by mass or more based on the total amount of the electrolyte slurry, and 50% by mass or less, 40% by mass or less, or 30. It may be mass% or less.

The content of the oxide particles may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, and 80% by mass or less and 70% by mass or less, based on the total amount of the non-volatile content in the electrolyte slurry. , Or 60% by mass or less. As a result, the content of the oxide particles in the obtained electrolyte layer becomes the same as the content.

The battery slurry composition may contain fibers such as cellulose fibers as other components.

In the battery slurry composition, the content of the polymer, the ionic liquid, the electrolyte salt, and the dispersion medium can be produced from the viewpoint of being able to produce a member for the battery by coating and suppressing the reprecipitation of the contained components. The mass ratio of the total content of the polymer, the ionic liquid, and the electrolyte salt to the total (hereinafter, may be simply referred to as “mass ratio”) is 0.1 to 0.3 (polymer, ionic liquid, and Total content of electrolyte salt / total content of polyma, ionic liquid, electrolyte salt, and dispersion medium).

The lower limit of the mass ratio is 0.1 or more, preferably 0.12 or more, more preferably 0.14 or more, still more preferably 0., from the viewpoint of increasing the viscosity of the battery slurry composition and facilitating application. It is 15 or more. The upper limit of the mass ratio is 0.3 or less, preferably 0.29 or less, more preferably 0.27 or less, still more preferably 0.2, from the viewpoint of suppressing reprecipitation of the contained components from the battery slurry. It is as follows. The mass ratios are 0.1 to 0.29, 0.1 to 0.27, 0.1 to 0.2, 0.12 to 0.3, 0.12 to 0.29, 0.12 to 0. 27, 0.12 to 0.2, 0.14 to 0.3, 0.14 to 0.29, 0.14 to 0.27, 0.14 to 0.2, 0.15 to 0.3, It may be 0.15 to 0.29, 0.15 to 0.27, or 0.15 to 0.2.

When the battery slurry composition is an electrode mixture slurry, the mass ratio is preferably 0.2 or more, more preferably 0.21 or more, still more preferably 0.22 or more, and preferably 0.3. Below, it is more preferably 0.29 or less, still more preferably 0.28 or less. When the battery slurry composition is an electrode mixture slurry, the mass ratios are 0.2 to 0.3, 0.2 to 0.29, 0.2 to 0.28, 0.21 to 0.3, It may be 0.21 to 0.29, 0.21 to 0.28, 0.22 to 0.3, 0.22 to 0.29, or 0.22 to 0.28.

When the battery slurry composition is an electrolyte slurry, the mass ratio is preferably 0.13 or more, more preferably 0.15 or more, still more preferably 0.16, from the viewpoint of preferably producing an electrolyte sheet described later. It is more than that, and is preferably 0.3 or less, 0.29 or less, 0.28 or less, 0.25 or less, or 0.2 or less. When the battery slurry composition is an electrolyte slurry, the mass ratios are 0.13 to 0.3, 0.13 to 0.29, 0.13 to 0.28, 0.13 to 0.25, 0. 13-0.2, 0.15-0.3, 0.15-0.29, 0.15-0.28, 0.15-0.25, 0.15-0.2, 0.16- It may be 0.3, 0.16 to 0.29, 0.16 to 0.28, 0.16 to 0.25, or 0.16 to 0.2.

When the battery slurry composition is an electrolyte slurry, it is preferably 0.1 or more, more preferably 0.11 or more, still more preferably 0, from the viewpoint of producing a battery member by applying the electrolyte slurry (details will be described later). It is .13 or more, preferably 0.25 or less, more preferably 0.23 or less, still more preferably 0.2 or less. When the battery slurry composition is an electrolyte slurry, the mass ratios are 0.1 to 0.25, 0.1 to 0.23, 0.1 to 0.2, 0.11 to 0.25, 0. It may be 11 to 0.23, 0.11 to 0.2, 0.13 to 0.25, 0.13 to 0.23, or 0.13 to 0.2.

Subsequently, a method for manufacturing an electrode, an electrolyte sheet, or a battery member using the above-mentioned battery slurry composition will be described.

<Method of manufacturing electrodes>
Using the above-mentioned battery slurry composition, an electrode (positive electrode 6 or negative electrode 8) having a current collector and an electrode mixture layer in this order can be manufactured. The method for manufacturing an electrode according to one embodiment includes a step of applying the above-mentioned battery slurry composition on one surface of a current collector to form an electrode mixture layer. In this method for manufacturing an electrode, the battery slurry composition may be the electrode mixture slurry described above.

As an example of the electrode manufacturing method according to the present embodiment, a method of manufacturing the positive electrode 6 will be described. FIG. 3 is a schematic cross-sectional view showing a method of manufacturing the positive electrode 6 according to the embodiment. In this manufacturing method, first, as shown in FIG. 3A, a positive electrode current collector 9 is prepared.

The positive electrode current collector 9 may be a metal such as aluminum, titanium, tantalum, or an alloy thereof. Since the positive electrode current collector 9 is lightweight and has a high weight energy density, it is preferably aluminum or an alloy thereof. The thickness of the positive electrode current collector 9 may be 10 μm or more, and may be 100 μm or less.

Next, as shown in FIG. 3B, a positive electrode mixture slurry is applied on one surface 9a of the positive electrode current collector 9 to provide a layer 10A of the positive electrode mixture slurry. The positive electrode mixture slurry contains components that can be contained in the battery slurry composition described above.

Examples of the method of applying the positive electrode mixture slurry include a method of applying using an applicator, a method of applying by spraying, and the like. The thickness of the layer 10A of the positive electrode mixture slurry may be, for example, 5 to 100 μm.

Next, the dispersion medium contained in the layer 10A of the positive electrode mixture slurry is volatilized. The method for volatilizing the dispersion medium may be, for example, a method of drying by heating, a method of reducing the pressure, a method of combining the pressure reduction and the heating, and the like. By volatilizing the dispersion medium, the positive electrode mixture layer 10 is formed, and the positive electrode 6 as shown in FIG. 3C can be obtained.

In this manufacturing method, since the above-mentioned battery slurry composition is used, the positive electrode 6 can be manufactured by coating, and the positive electrode mixture layer 10 is formed with a uniform thickness and adheres to the positive electrode current collector 9. It is also possible to manufacture a positive electrode 6 having excellent properties.

The manufacturing method of the negative electrode 8 according to the embodiment may be the same as the manufacturing method of the positive electrode 6 described above. That is, the method for manufacturing the negative electrode 8 is a method in which "positive electrode" is read as "negative electrode" in the above-mentioned manufacturing method for the positive electrode 6.

The negative electrode current collector 11 used in the method for manufacturing the negative electrode 8 may be a metal such as aluminum, copper, nickel, stainless steel, an alloy thereof, or the like. Since the negative electrode current collector 11 is lightweight and has a high weight energy density, it is preferably aluminum or an alloy thereof. The negative electrode current collector 11 is preferably copper from the viewpoint of ease of processing into a thin film and cost. The thickness of the negative electrode current collector 11 may be 10 μm or more, and may be 100 μm or less.

<Manufacturing method of electrolyte sheet>
An electrolyte sheet can be produced by using the above-mentioned battery slurry composition. The electrolyte sheet is a sheet including a base material and an electrolyte layer formed on one surface of the base material, and is used to obtain the electrolyte layer 7.

The method for producing an electrolyte sheet according to one embodiment includes a step of applying the above-mentioned battery slurry composition on one surface of a base material to form an electrolyte layer. In this method for producing an electrolyte sheet, the battery slurry composition may be the above-mentioned electrolyte slurry.

FIG. 4 is a schematic cross-sectional view showing a method for manufacturing an electrolyte sheet according to an embodiment. In this manufacturing method, first, as shown in FIG. 4A, the base material 13 is prepared.

The base material 13 is not limited as long as it has heat resistance that can withstand heating when the dispersion medium is volatilized, does not react with the battery slurry composition, and does not swell due to the battery slurry composition. , For example, made of resin. More specifically, the base material 13 may be a film made of a resin (general-purpose engineering plastic) such as polyethylene terephthalate, polytetrafluoroethylene, polyimide, polyethersulfone, and polyetherketone. The thickness of the base material 13 may be, for example, 5 μm or more and 100 μm or less.

Next, as shown in FIG. 4B, an electrolyte slurry is applied onto one surface 13a of the base material 13 to provide a layer 7A of the electrolyte slurry. The electrolyte slurry is the battery slurry composition described above.

The method of applying the electrolyte slurry may be the same as the method of applying the positive electrode mixture slurry described above. The thickness of the layer 7A of the electrolyte slurry may be, for example, 5 to 30 μm.

Next, the dispersion medium contained in the layer 7A of the electrolyte slurry is volatilized. The method for volatilizing the dispersion medium may be the same as the method for volatilizing the dispersion medium contained in the layer 10A of the positive electrode mixture slurry described above. By volatilizing the dispersion medium, the electrolyte layer 7 is formed, and the electrolyte sheet 14 as shown in FIG. 4C can be obtained.

Since the above-mentioned battery slurry composition is used in this production method, the electrolyte sheet 14 can be produced by coating, and the electrolyte layer 7 having a uniform thickness and excellent strength is formed and can stand on its own. The electrolyte sheet 14 can be manufactured. Further, in the obtained electrolyte sheet 14, the base material 13 can be easily peeled off.

The electrolyte sheet 14 can be continuously manufactured while being wound into a roll. In that case, the surface of the electrolyte layer 7 may come into contact with the back surface of the base material 13 and a part of the electrolyte layer 7 may adhere to the base material 13 to damage the electrolyte layer 7. In order to prevent such a situation, as another embodiment, the electrolyte sheet may be provided with a protective material on the side opposite to the base material 13 of the electrolyte layer 7.

The protective material may be any material that can be easily peeled off from the electrolyte layer 7, and is preferably a non-polar resin film such as polyethylene, polypropylene, or polytetrafluoroethylene. When a non-polar resin film is used, the electrolyte layer 7 and the protective material do not stick to each other, and the protective material can be easily peeled off.

The secondary battery 1 can be manufactured by using the electrolyte sheet 14, the positive electrode 6 and the negative electrode 8. In this manufacturing method, for example, the secondary battery 1 is obtained by peeling the base material 13 from the electrolyte sheet 14 and, in some cases, the protective material, and laminating the positive electrode 6, the electrolyte layer 7, and the negative electrode 8 by, for example, laminating. Be done. At this time, the electrolyte layer 7 is located on the positive electrode mixture layer 10 side of the positive electrode 6 and on the negative electrode mixture layer 12 side of the negative electrode 8, that is, the positive electrode current collector 9, the positive electrode mixture layer 10, and the electrolyte layer 7. , The negative electrode mixture layer 12 and the negative electrode current collector 11 are laminated in this order.

<Manufacturing method of battery parts>
Using the above-mentioned battery slurry composition, a battery member (positive electrode member or negative electrode member) including a current collector, an electrode mixture layer, and an electrolyte layer in this order can be manufactured. The method for manufacturing the battery member according to one embodiment includes a step of forming an electrode mixture intermediate layer containing an electrode active material on one surface of a current collector and a method on the opposite side of the current collector of the electrode mixture intermediate layer. A step of applying the above-mentioned battery slurry composition on the surface and a step of volatilizing the dispersion medium to form an electrode mixture layer and an electrolyte layer are provided.

As an example of the method for manufacturing the battery member according to the present embodiment, a method for manufacturing the positive electrode member will be described. FIG. 5 is a schematic cross-sectional view showing a method of manufacturing a positive electrode member according to an embodiment. In this manufacturing method, first, as shown in FIG. 5A, a positive electrode current collector 9 is prepared.

Next, as shown in FIG. 5B, the positive electrode mixture intermediate layer 10B is formed on one surface 9a of the positive electrode current collector 9.

The method of forming the positive electrode mixture intermediate layer 10B is, in one embodiment, a method of applying the positive electrode mixture precursor onto one surface 9a of the positive electrode current collector 9. The positive electrode mixture precursor may be the above-mentioned battery slurry composition, or may be a composition different from the battery slurry composition. When the positive electrode mixture precursor is a composition different from the battery slurry composition, the positive electrode mixture precursor contains, in one embodiment, a positive electrode active material, a polymer, and a dispersion medium. The positive electrode active material, the polymer, and the dispersion medium may be the same as those described above. That is, the positive electrode mixture precursor does not have to contain an ionic liquid and an electrolyte salt.

The method of applying the positive electrode mixture precursor on one surface 9a of the positive electrode current collector 9 may be the same as the method of applying the positive electrode mixture slurry described above. By applying the positive electrode mixture precursor, the positive electrode mixture intermediate layer 10B is formed. The thickness of the positive electrode mixture intermediate layer 10B may be, for example, 5 to 100 μm.

After the positive electrode mixture precursor is applied, the dispersion medium contained in the positive electrode mixture precursor may be volatilized. That is, the "positive electrode mixture intermediate layer" includes a layer formed of the positive electrode mixture precursor and a layer formed by volatilizing a part or all of the dispersion medium from the positive electrode mixture precursor. .. The method for volatilizing the dispersion medium may be the same as the method for volatilizing the dispersion medium contained in the layer 10A of the positive electrode mixture slurry described above.

Next, as shown in FIG. 5C, an electrolyte slurry is applied on the surface 10a of the positive electrode mixture intermediate layer 10B opposite to the positive electrode current collector 9, and the layer 7A of the electrolyte slurry is provided. The electrolyte slurry is the battery slurry composition described above.

In this production method, when the positive electrode mixture intermediate layer 10B does not contain the ionic liquid and the electrolyte salt, that is, when the positive electrode mixture precursor does not contain the ionic liquid and the electrolyte salt, the electrolyte slurry layer 7A is provided. Occasionally, the ionic liquid and the electrolyte salt contained in the layer 7A of the electrolyte slurry move from the layer 7A of the electrolyte slurry to the positive electrode mixture intermediate layer 10B as the ionic liquid electrolyte. It is presumed that this movement is due to an action of reducing the concentration difference of the ionic liquid electrolytic solution between the positive electrode mixture intermediate layer 10B and the layer 7A of the electrolyte slurry, an action due to gravity, or a capillary phenomenon. Therefore, the positive electrode mixture intermediate layer 10B after the electrolyte slurry layer 7A is applied contains an ionic liquid and an electrolyte salt.

Next, the dispersion medium contained in the positive electrode mixture intermediate layer 10B and the electrolyte slurry layer 7A is volatilized. The method for volatilizing the dispersion medium may be the same as the method for volatilizing the dispersion medium contained in the layer 10A of the positive electrode mixture slurry described above. By volatilizing the dispersion medium, the positive electrode mixture layer 10 and the electrolyte layer 7 are formed, and the positive electrode member 15 as shown in FIG. 5D can be obtained.

In this production method, since the above-mentioned battery slurry composition is used, the electrolyte slurry can be applied on the positive electrode mixture intermediate layer 10B with a uniform thickness, and the electrolyte slurry is applied to the positive electrode mixture intermediate. It can also be facilitated to penetrate layer 10B.

The method for manufacturing the negative electrode member according to the embodiment may be the same as the method for manufacturing the positive electrode member 15 described above. That is, the method for manufacturing the negative electrode member is a method in which "positive electrode" is read as "negative electrode" in the above-mentioned manufacturing method for the positive electrode member 15.

The secondary battery 1 can be obtained by using the positive electrode member 15 and the negative electrode member obtained by the above-mentioned manufacturing method. The secondary battery 1 can be manufactured by pressing the surface of the positive electrode member 15 on the electrolyte layer 7 side and the surface of the negative electrode member 15 on the electrolyte layer 7 side together.

The embodiments described above can take various modifications.

As a first modification, the battery slurry composition may be used in the manufacture of a so-called bipolar secondary battery. FIG. 6 is an exploded perspective view showing an embodiment of the electrode group of the bipolar type secondary battery. The electrode group 2B includes a positive electrode 6, a first electrolyte layer 7, a bipolar electrode 16, a second electrolyte layer 7, and a negative electrode 8 in this order. The bipolar electrode 16 includes a bipolar electrode current collector 17, a positive electrode mixture layer 10 provided on the negative electrode side surface (positive electrode surface) of the bipolar electrode current collector 17, and a positive electrode side surface (positive electrode surface) of the bipolar electrode current collector. It is provided with a negative electrode mixture layer 12 provided on the negative electrode surface).

The above-mentioned battery slurry composition can be used for producing the positive electrode 6, the negative electrode 8, and the electrolyte layer 7 in the bipolar secondary battery, and forms the positive electrode mixture layer 10 and the negative electrode mixture layer in the bipolar electrode 16. It can be used to form twelve.

Further, the electrode group 2B in the bipolar type secondary battery includes a first battery member having a positive electrode 6 and an electrolyte layer 7 in this order, and a second battery member having a negative electrode 8 and an electrolyte layer 7 in this order. It can be seen that the battery member (negative electrode member) is included. Further, it can be seen that the electrode group 2B includes a third battery member (bipolar battery member) including the electrolyte layer 7, the bipolar electrode 16, and the electrolyte layer 7 in this order. The above-mentioned battery slurry composition can also be used for forming the positive electrode mixture layer 10 and the negative electrode mixture layer 12 in the manufacture of these battery members.

As a second modification, the battery slurry composition can also be used to form an interface cambium. The interface cambium is a layer provided between the positive electrode mixture layer and the electrolyte layer on the positive electrode and / or between the negative electrode mixture layer and the electrolyte layer on the negative electrode. The interface forming layer makes it possible to form the interface between the electrode mixture layer and the electrolyte layer more satisfactorily, and it becomes possible to further increase the ionic conductivity in the secondary battery. The method of forming the interface forming layer may be, for example, a method of applying the above-mentioned battery slurry composition on one surface of the electrolyte layer to volatilize the dispersion medium. The battery slurry composition used for forming the interface cambium preferably contains the components contained in the above-mentioned electrolyte slurry.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In the following, when expressing the composition of an ionic liquid (ionic liquid electrolyte) in which an electrolyte salt is dissolved, it may be expressed as "concentration of electrolyte salt / type of electrolyte salt / type of ionic liquid". ..

<Examples 1-1 to 1-3, Comparative examples 1-1 to 1-5>
Based on the composition shown in Table 1, layered lithium-nickel-manganese-cobalt composite oxide (NMC, positive electrode active material), acetylene black (conductive material, average particle size 48 nm, product name: HS-100, Denka Co., Ltd.) ), A polymer solution in which polyvinylidene fluoride was dissolved in a dispersion medium (NMP) (binder, solid content 12% by mass), and optionally a dispersion medium (NMP) were kneaded using a kneading device. An ionic liquid (1.5 moL / L / LiFSI / EMI-FSI) in which an electrolyte salt was dissolved was added as an ionic liquid electrolytic solution and further kneaded to prepare a positive electrode mixture slurry.

<Examples 1-4 to 1-5, Comparative examples 1-6 to 1-8>
[Synthesis of Polymer (Synthesis Example 1)]
1804 g of purified water was placed in a 3 liter separable flask equipped with a stirrer, a thermometer, a cooling tube and a nitrogen gas introduction tube, and the temperature was raised to 74 ° C. while stirring under the condition of a nitrogen gas aeration rate of 200 mL / min. After that, the ventilation of nitrogen gas was stopped. Next, an aqueous solution prepared by dissolving 0.968 g of ammonium persulfate as a polymerization initiator in 76 g of purified water was added, and immediately, 183.8 g of acrylonitrile as a nitrile group-containing monomer and 9.7 g of acrylic acid as a carboxyl group-containing monomer were added. (Ratio of 0.039 mol to 1 mol of acrylonitrile) and 6.5 g of monomeric methoxytriethylene glycol acrylate (trade name: NK ester AM-30G, Shin-Nakamura Chemical Industry Co., Ltd.) (to 1 mol of acrylonitrile) The mixed solution (at a ratio of 0.0085 mol) was added dropwise over 2 hours while maintaining the temperature of the system at 74 ± 2 ° C. Subsequently, an aqueous solution prepared by dissolving 0.25 g of ammonium persulfate in 21.3 g of purified water was additionally added to the suspended reaction system, the temperature was raised to 84 ° C., and then the temperature of the system was maintained at 84 ± 2 ° C. The reaction proceeded for 2.5 hours. Then, after cooling to 40 ° C. over 1 hour, stirring was stopped and the mixture was allowed to cool overnight at room temperature to precipitate a copolymer (polymer A) in which acrylic acid and a linear ether group were added to a polyacrylonitrile skeleton. Obtained liquid. The reaction solution was suction-filtered, and the collected wet precipitate was washed 3 times with 1800 g of purified water and then vacuum-dried at 80 ° C. for 10 hours to isolate and purify the polymer A.

(Preparation of positive electrode mixture slurry)
A positive electrode mixture slurry was prepared by the same method as in Example 1-1 except that the polymer in the polymer solution was changed to the polymer A synthesized in Synthesis Example 1 above.

<Examples 1-6 to 1-7, Comparative Examples 1-9 to 1-11>
Based on the composition shown in Table 1, graphite (negative electrode active material, Hitachi Chemical Co., Ltd.), carbon fiber (conductive material, product name: VGCF-H, Showa Denko Co., Ltd.), and polyvinylidene fluoride as a dispersion medium (NMP) The dissolved polymer solution (binder, solid content 13% by mass), and optionally the dispersion medium (NMP), was kneaded using a kneader. An ionic liquid (1.5 moL / L / LiFSI / EMIFSI) in which an electrolyte salt was dissolved was added as an ionic liquid electrolytic solution and further kneaded to prepare a negative electrode mixture slurry.

<Presence / absence of gelation>
The positive electrode mixture slurry or the negative electrode mixture slurry in the container of the kneading apparatus was visually observed to confirm the presence or absence of gelation due to the reprecipitation of the contained components. The gelled slurry by reprecipitation was designated as +, and the non-gelled slurry was designated as-. The results are shown in Table 1. The "mass ratio" in Table 1 is the mass ratio of the total content of the polymer and the ionic liquid electrolytic solution to the total content of the polymer, the ionic liquid electrolytic solution, and the dispersion medium, and the same applies below. Is.

As shown in Table 1, the mass ratio of the total content of the polymer and the ionic liquid electrolyte to the total content of the polymer, the ionic liquid electrolyte, and the dispersion medium is in the range of 0.1 to 0.3. Reprecipitation did not occur in the electrode mixture slurry of the example inside. On the other hand, in the electrode mixture slurry of the comparative example in which the mass ratio was outside the range of 0.1 to 0.3, gelation due to reprecipitation of the polymer occurred.

<Evaluation of coating formability>
Regarding the electrode mixture slurry that did not gel, evaluate whether it can be applied to the current collector (aluminum foil with a thickness of 15 μm), and those that could be applied normally are A, and those that could not be applied normally. It was designated as B. The requirements for determining that the coating was successful were that the current collector could not be seen by observing from the electrode mixture slurry side after application of the electrode mixture slurry, and that the coating could be performed with the desired coating width or coating amount. .. The results are shown in Table 1. As a result, the electrode mixture slurry of Comparative Example 1-5 and Comparative Example 1-11 has too low viscosity, so that the electrode mixture slurry flows out from the current collector when the desired coating amount is applied. It could not be applied normally on the current collector.

<Examples 2-1 to 2-6, Comparative Examples 2-1 to 2-3>
Based on the composition shown in Table 2, as a copolyma (PVDF-HFP) of vinylidene fluoride and hexafluoropyrene, SiO ₂ particles (product name: AEROSIL RX50, manufactured by Nippon Aerosil Co., Ltd.), and an ionic liquid electrolyte. An ionic liquid (1.5 moL / L / LiFSI / EMI-FSI) in which an electrolyte salt is dissolved and cellulose fibers (average length 50 μm, average fiber diameter 0.1 μm) are dispersed in a dispersion medium (NMP). An electrolyte slurry was prepared by kneading with a kneading device.

<Examples 2-7 to 2-9>
An electrolyte slurry was prepared by the same method as in Example 2-1 except that the dispersion medium was changed to DMSO.

<Presence / absence of gelation>
The electrolyte slurry in the container of the kneading apparatus was visually observed to confirm the presence or absence of gelation due to the reprecipitation of the contained components. The gelled slurry by reprecipitation was designated as +, and the non-gelled slurry was designated as-. The results are shown in Table 2.

As shown in Table 2, the mass ratio of the total content of the polymer and the ionic liquid electrolyte to the total content of the polymer, the ionic liquid electrolyte, and the dispersion medium is in the range of 0.1 to 0.3. In the electrolyte sheet prepared using the electrolyte slurry of the example in the above, reprecipitation did not occur. On the other hand, in the electrolyte sheet prepared by using the electrolyte slurry of the comparative example in which the mass ratio is out of the range of 0.1 to 0.3, reprecipitation of the polymer was particularly generated.

<Evaluation of coating formability>
It was evaluated whether or not the electrolyte slurry that did not gel could be applied to a polyethylene terephthalate base material (product name: Theonex RQ51, manufactured by Teijin DuPont Film Co., Ltd., thickness 38 μm), and applied normally. The one that was made was designated as A, and the one that could not be applied normally was designated as B. The requirements for determining that the coating was successful were that the substrate could not be seen when observed from the electrolyte slurry side after coating the electrolyte slurry, and that the coating could be performed with the desired coating width or coating amount. The results are shown in Table 2. As a result, in the electrode mixture slurry of Comparative Example 2-3, the viscosity is too low, and when an attempt is made to apply the desired coating amount, the electrolyte slurry flows out from the base material and is normally applied onto the base material. I couldn't.

An electrolyte sheet was prepared using the electrolyte slurry of Examples 2-4 to 2-9. The electrolyte slurry was applied onto a base material made of polyethylene terephthalate (product name: Theonex RQ51, manufactured by Teijin DuPont Film Co., Ltd., thickness 38 μm) using an applicator. The applied electrolyte slurry was heated and dried at 80 ° C. for 1 hour to volatilize the dispersion medium to obtain an electrolyte sheet.

As a result, since the electrolyte slurry of Examples 2-4 to 2-9 did not show reprecipitation of the polymer, it could be applied to one surface of the base material with a uniform thickness, and the surface condition was good, which was a drawback. We were able to produce a self-supporting electrolyte sheet.

1 ... Secondary battery, 6 ... Positive electrode, 7 ... Electrode layer, 7A ... Electrode slurry layer, 8 ... Negative electrode, 9 ... Positive electrode current collector, 10 ... Positive electrode mixture layer, 10A ... Positive electrode mixture slurry layer, 10B ... Positive electrode mixture intermediate layer, 11 ... Negative electrode current collector, 12 ... Negative electrode mixture layer, 13 ... Base material, 14 ... Electrode sheet, 15 ... Positive electrode member, 16 ... Bipolar electrode, 17 ... Bipolar electrode current collector.

Claims

With polymer
With ionic liquids
At least one electrolyte salt selected from the group consisting of lithium salt, sodium salt, calcium salt and magnesium salt, and
Contains a dispersion medium,
The mass ratio of the total content of the polymer, the ionic liquid, and the electrolyte salt to the total content of the polymer, the ionic liquid, the electrolyte salt, and the dispersion medium is 0.1 to 0.3. Slurry composition for batteries.
The battery slurry composition according to claim 1, further containing an electrode active material.
The battery slurry composition according to claim 2, wherein the mass ratio is 0.2 to 0.3.
The battery slurry composition according to claim 1, further containing oxide particles.
The battery slurry composition according to claim 4, wherein the mass ratio is 0.13 to 0.3.
The battery slurry composition according to claim 4, wherein the mass ratio is 0.1 to 0.25.
A method for manufacturing an electrode including a current collector and an electrode mixture layer formed on one surface of the current collector.
The manufacturing method comprises a step of applying the battery slurry composition according to any one of claims 1 to 3 onto one surface of the current collector to form the electrode mixture layer. Production method.
A method for producing an electrolyte sheet comprising a base material and an electrolyte layer formed on one surface of the base material.
The manufacturing method comprises a step of applying the battery slurry composition according to claim 1, 4 or 5 onto one surface of the base material to form the electrolyte layer.
A method for manufacturing a battery member including a current collector, an electrode mixture layer, and an electrolyte layer in this order.
The manufacturing method includes a step of forming an electrode mixture intermediate layer containing an electrode active material on one surface of the current collector, and a step of forming the electrode mixture intermediate layer.
The step of applying the battery slurry composition according to claim 1, 4 or 6 on the surface of the electrode mixture intermediate layer opposite to the current collector.
A method for manufacturing a battery member, comprising a step of volatilizing the dispersion medium to form the electrode mixture layer and the electrolyte layer.