JP2018095621A - Zwitterionic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound that can serve as an electrode protective material or a lithium ion conductive material.SOLUTION: A zwitterionic compound contains a quaternary ammonium cation, anion, a siloxane skeleton or a polyphosphoric acid skeleton.SELECTED DRAWING: Figure 2

Description

  The present invention relates to zwitterionic compounds.

  Secondary batteries typified by lithium ion secondary batteries are currently used mainly as power sources for portable electronic devices, and are also put into practical use as power sources for electric vehicles. Along with the diversification of usage modes, there is a demand for higher capacity of secondary batteries. Therefore, studies have been made to increase the capacity of secondary batteries by driving them at a high voltage. However, when the secondary battery is driven at a high voltage, there is a problem that oxidative decomposition of the electrolytic solution due to contact with the positive electrode active material in an oxidized state occurs.

  Therefore, as a technique for reducing direct contact between the positive electrode active material and the electrolytic solution, a technique for forming a protective layer on the surface of the positive electrode active material layer containing the positive electrode active material has been proposed.

  For example, Patent Document 1 discloses a technique for providing a coat layer that covers the surface of a positive electrode active material. Specifically, a technique is disclosed in which a positive electrode composed of a current collector and a positive electrode active material layer is immersed in a polyethyleneimine solution and a polyethylene glycol solution, and the positive electrode is coated with a polymer.

  Patent Document 2 also discloses a technique of providing a coat layer that covers the surface of the positive electrode active material. Specifically, a technique is disclosed in which a positive electrode composed of a current collector and a positive electrode active material layer is immersed in a polyethylene glycol solution, and the positive electrode is coated with a polymer.

JP 2013-243105 A JP 2014-096343 A

  However, since the polymer is inherently a resistance factor against the movement of charge carriers such as lithium ions, it can be said that the secondary battery to which the technology disclosed in Patent Document 1 and Patent Document 2 is applied has a problem in the function as a battery. . Here, this inventor recognized the necessity of the lithium ion conductive material which can become a protective material of an electrode.

  This invention is made | formed in view of this situation, and it aims at providing the compound which can become a lithium ion conductive material.

  As a lithium ion conductive material that can serve as a protective material for an electrode, affinity for lithium ions is required, but the degree is not so strong as to inhibit the movement of lithium ions. For example, in the case of a lithium ion conductive material containing polyacrylic acid, the carboxylic acid constituting acrylic acid shows affinity with lithium ions, but the carboxylic acid formed by the exchange of protons and lithium ions of the carboxylic acid. Since lithium acid salt is electrically neutral and stable, lithium ions are trapped in polyacrylic acid, and as a result, movement of lithium ions is inhibited. Therefore, the lithium ion conductive material containing polyacrylic acid is not appropriate as a protective material for the electrode.

  Therefore, the present inventor has focused on zwitterionic compounds containing both a cation and an anion in the molecule. In the case of a zwitterionic compound, the anion shows a certain degree of affinity with the lithium ion, but due to the presence of a cation in the zwitterionic compound, the lithium ion is completely trapped in the zwitterionic compound. It can be suppressed. Moreover, the inventor has conceived of using a quaternary ammonium cation as the cation of the zwitterionic compound. The reason is that if the proton is a primary to tertiary ammonium cation, the proton and lithium ion may be replaced by ion exchange, and the lithium ion may be trapped. This is because a quaternary ammonium cation that does not exist is not possible.

  The inventor synthesized a zwitterionic compound containing both a quaternary ammonium cation and an anion in the molecule, and manufactured an electrode and a lithium ion secondary battery using the zwitterionic compound as a protective material. And when this inventor charged / discharged the lithium ion secondary battery which comprises the said electrode, although lithium ion conductivity was shown, it discovered that there existed a subject in the maintenance rate of a capacity | capacitance. That there is a problem in the capacity maintenance rate means that the zwitterionic compound does not sufficiently protect the electrode. In the zwitterionic compound containing only both the quaternary ammonium cation and the anion, the inventor peels off from the electrode or dissolves in the electrolyte during charge / discharge of the lithium ion secondary battery. Estimated that it could not be protected.

  As a result of further studies by the present inventor, the present inventor has conceived a zwitterionic compound containing a quaternary ammonium cation and an anion in the molecule and a siloxane skeleton or a polyphosphate skeleton. And when this zwitterionic compound was actually synthesized and tested, the present inventor found that the zwitterionic compound could suitably protect the electrode. Based on this discovery, the present inventor has completed the present invention.

  The zwitterionic compound of the present invention includes a quaternary ammonium cation, an anion, and a siloxane skeleton or a polyphosphate skeleton.

  According to the present invention, a zwitterionic compound that can be a lithium ion conductive material can be provided.

2 is an infrared absorption spectrum of Intermediate A. 2 is an infrared absorption spectrum of the lithium ion conductive material of Example 1.

  Below, the form for implementing this invention is demonstrated. Unless otherwise specified, the numerical range “ab” described herein includes the lower limit “a” and the upper limit “b”. The numerical range can be configured by arbitrarily combining these upper limit value and lower limit value and the numerical values listed in the examples. Furthermore, numerical values arbitrarily selected from these numerical ranges can be used as new upper and lower numerical values.

  The zwitterionic compound of the present invention includes a quaternary ammonium cation, an anion, and a siloxane skeleton or a polyphosphate skeleton. The zwitterionic compound of the present invention is preferably in a gel state.

  A zwitterionic compound is a compound containing both a cation and an anion in one molecule. A simple salt of a cation and an anion such as ammonium acetate is not a zwitterionic compound. The zwitterionic compound of the present invention is a compound containing a quaternary ammonium cation, an anion, and a siloxane skeleton or a polyphosphate skeleton in one molecule.

  In the present invention, the quaternary ammonium cation means a cation in which all four bonds of nitrogen are bonded to carbon, oxygen, sulfur or nitrogen. The bond between nitrogen and carbon may be a single bond, a double bond, or a triple bond. From the viewpoint of chemical stability, the quaternary ammonium cation is composed of four single bonds of nitrogen and carbon, or two single bonds of nitrogen and carbon and one of nitrogen and carbon. It is preferably composed of a double bond.

As the anion, an anion derived from an acid is preferable. As an anion derived from an acid, -SO ₃ ^- sulfonic acid represented by anionic, -CO ₂ ^- carboxylic acid represented by anions, -PO (OH) ₂ ^- phosphonic acid anion represented, and, (- O-) ₂ PO (OH) ^- and -O-PO (OH) ₂ ^- can be exemplified phosphoric acid anion represented by.

  A siloxane skeleton means a structure having a Si—O—Si bond. The polyphosphoric acid skeleton means a structure with-[P (= O) (OH) -O-] n-. Here, n is an integer of 2 or more. It can be said that the zwitterionic compound of the present invention is imparted with a function as a protective material for the electrode due to the presence of the siloxane skeleton or the polyphosphoric acid skeleton, and the release from the electrode is suppressed.

The zwitterionic compound of the present invention can also be expressed as a zwitterionic compound having a structure of any one of the following general formulas 1 to 3.
General formula 1: _Skeleton- (L) _{n- Cation-} (L) _n - _Anion
General formula 2: _Skeleton- (L) _n - _Anion- (L) _{n- Cation}
General formula 3: _Anion- (L) _n- S _kelton- (L) _{n- Cation
(S} keleton is _{.C ation} which means a siloxane skeleton or polyphosphoric acid skeleton means a linker each .L independently _{.A nion} to mean quaternary ammonium cation to mean anions, linker have a substituent And n is independently 0 or 1. The linker may form a ring together with _Skeleton and / or _Cation .)

  The organic chain of the linker may be composed of a hydrocarbon chain, or may be composed of a hydrocarbon chain and a hetero element. Examples of hetero elements include N, O, and S. As an organic chain composed of a hydrocarbon chain and a hetero element, hydrocarbon chain-O-hydrocarbon chain, hydrocarbon chain-O-C = O-hydrocarbon chain, hydrocarbon chain-O-C = O-O- Hydrocarbon chain, hydrocarbon chain-NH-hydrocarbon chain, hydrocarbon chain-NH-C = O-hydrocarbon chain, hydrocarbon chain-NH-C = O-NH-hydrocarbon chain, hydrocarbon chain-S- An example is a hydrocarbon chain.

  The organic chain of the linker may be either saturated or unsaturated, or may be linear, branched or cyclic, or may be a combination of these states.

The number of carbon atoms and the number of hetero elements in the organic chain of the linker are not limited. Examples of the total number of carbon atoms and heteroelements in the organic chain include 1 to 18, 2 to 12, and 3 to 8. In the linker connecting the C _ation and _{A nion,} as the element number of the shortest distance between the _{C ation} and _{A nion,} preferably in the range of 1 to 6, more preferably in the range of 2-4. If an excessive number of elements of the shortest distance between the C _ation and A _nion, since the action of the quaternary ammonium cation to anion is weakened, there is a fear that a state in which lithium ions are trapped in the anion.

  The term “optionally substituted” for the linker will be described. The “optionally substituted” organic chain means an organic chain in which one or more of hydrogens in the organic chain are substituted with a substituent, or an organic chain having no particular substituent. To do.

  Examples of the substituent in the phrase “may have a substituent” include an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an unsaturated cycloalkyl group, an aromatic group, a heterocyclic group, halogen, OH SH, CN, SCN, OCN, nitro group, alkoxy group, unsaturated alkoxy group, amino group, alkylamino group, dialkylamino group, aryloxy group, acyl group, alkoxycarbonyl group, acyloxy group, aryloxycarbonyl group, Acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, sulfo group, carboxyl group, Hydroxamic acid group, sul Inomoto, hydrazino group, an imino group, a silyl group. These substituents may be further substituted with a substituent. When there are two or more substituents, the substituents may be the same or different. As the substituent, those having weak interaction with lithium ions are preferable.

When the linker forms a ring together with _Cation , the ring skeleton includes a pyrrole skeleton, an imidazole skeleton, a triazole skeleton, a tetrazole skeleton, a pyrazole skeleton, a pyridine skeleton, a pyrazine skeleton, a pyrimidine skeleton, a pyridazine skeleton, an azepine skeleton, Diazepine skeleton, oxazole skeleton, isoxazole skeleton, thiazole skeleton, isothiazole skeleton, furazane skeleton, oxadiazole skeleton, oxazine skeleton, oxadiazine skeleton, oxazepine skeleton, oxadiazepine skeleton, thiadiazole skeleton, thiazine skeleton, thiadiazine skeleton, thiazepine skeleton, thiadiazepine Skeleton, aziridine skeleton, azetidine skeleton, pyrroline skeleton, pyrrolidine skeleton, imidazoline skeleton, imidazolidine skeleton, triazoline skeleton, triazolidine skeleton, tetrazoli Skeleton, tetrazolidine skeleton, pyrazoline skeleton, pyrazolidine skeleton, dihydropyridine skeleton, tetrahydropyridine skeleton, piperidine skeleton, dihydropyrazine skeleton, tetrahydropyrazine skeleton, piperazine skeleton, dihydropyrimidine skeleton, tetrahydropyrimidine skeleton, perhydropyrimidine skeleton, dihydropyridazine skeleton, Tetrahydropyridazine skeleton, perhydropyridazine skeleton, dihydroazepine skeleton, tetrahydroazepine skeleton, perhydroazepine skeleton, dihydrodiazepine skeleton, tetrahydrodiazepine skeleton, perhydrodiazepine skeleton, dihydrooxazole skeleton, tetrahydrooxazole skeleton, dihydroisoxazole skeleton , Tetrahydroisoxazole skeleton, dihydrothiazole skeleton, tetrahydrothiazole skeleton Dihydroisothiazole skeleton, Tetrahydroisothiazole skeleton, Dihydrofurazane skeleton, Tetrahydrofurazane skeleton, Dihydrooxadiazole skeleton, Tetrahydrooxadiazole skeleton, Dihydrooxazine skeleton, Tetrahydrooxazine skeleton, Dihydrooxadiazine skeleton, Tetrahydrooxadiazine skeleton , Dihydrooxazepine skeleton, tetrahydrooxazepine skeleton, perhydrooxazepine skeleton, dihydrooxadiazepine skeleton, tetrahydrooxadiazepine skeleton, perhydrooxadiazepine skeleton, dihydrothiadiazole skeleton, tetrahydrothiadiazole skeleton, dihydrothiazine Skeleton, tetrahydrothiazine skeleton, dihydrothiadiazine skeleton, tetrahydrothiadiazine skeleton, dihydrothiazepine skeleton, tetrahydro Azepine skeleton, perhydrothiazepine skeleton, dihydrothiadiazepine skeleton, tetrahydrothiadiazepine skeleton, perhydrothiadiazepine skeleton, morpholine skeleton, thiomorpholine skeleton, indole skeleton, isoindole skeleton, indolizine skeleton, indazole skeleton, quinoline Skeleton, isoquinoline skeleton, quinolidine skeleton, purine skeleton, phthalazine skeleton, pteridine skeleton, naphthyridine skeleton, quinoxaline skeleton, quinazoline skeleton, cinnoline skeleton, pyrrolopyridine skeleton, benzoxazole skeleton, benzothiazole skeleton, benzimidazole skeleton, indoline skeleton, isoindoline Skeleton, dihydroindazole skeleton, perhydroindazole skeleton, dihydroquinoline skeleton, tetrahydroquinoline skeleton, perhydroquinoline skeleton, dihydroisoquino Phosphorus skeleton, tetrahydroisoquinoline skeleton, perhydroisoquinoline skeleton, dihydrophthalazine skeleton, tetrahydrophthalazine skeleton, perhydrophthalazine skeleton, dihydronaphthyridine skeleton, tetrahydronaphthyridine skeleton, perhydronaphthyridine skeleton, dihydroquinoxaline skeleton, tetrahydroquinoxaline skeleton, per Hydroquinoxaline skeleton, dihydroquinazoline skeleton, tetrahydroquinazoline skeleton, perhydroquinazoline skeleton, tetrahydropyrrolopyridine skeleton, dihydrocinnoline skeleton, tetrahydrocinnoline skeleton, perhydrocinnoline skeleton, dihydrobenzoxazine skeleton, dihydrobenzothiazine skeleton, pyra Dinomorpholine skeleton, dihydrobenzoxazole skeleton, perhydrobenzoxazole skeleton, dihydrobenzothi Tetrazole skeleton, perhydro benzothiazole skeleton, dihydro benzimidazole, a perhydro benzimidazole can be exemplified.

Next, the manufacturing method of the zwitterionic compound of this invention is demonstrated.
The zwitterionic compound of the present invention can be produced by reacting a quaternary ammonium cation precursor, an anion precursor, and a siloxane skeleton compound or a polyphosphate skeleton compound or a siloxane skeleton precursor or a polyphosphate skeleton precursor. . For a desired zwitterionic compound of the present invention, a compound to be a raw material and a synthesis route may be determined using a retro synthesis method.

  As a synthetic route, a quaternary ammonium cation precursor forms a covalent bond by nucleophilic attack on an anion precursor, siloxane skeleton compound or polyphosphate skeleton compound, or siloxane skeleton precursor or polyphosphate skeleton precursor. It is reasonable to select the synthesis route to be used.

  Examples of the quaternary ammonium cation precursor include primary amine compounds, secondary amine compounds, tertiary amine compounds, and polyamine compounds such as diamine compounds. The quaternary ammonium cation precursor may be a chain, may be cyclic, may be saturated, or may be unsaturated.

_{Examples of the} anion precursor include compounds represented by _Anion- L-LG (LG means a leaving group. _Anion and L are as described in General Formulas 1 to 3). As the leaving group of the anion precursor, those generally recognized as leaving groups such as halogen, methanesulfonate, trifluoromethanesulfonate and the like may be used. When the anion is a sulfonate anion, it is preferable to employ sultone, which is a cyclic ester of hydroxysulfonic acid, as the anion precursor. Sultone can react with an amine compound to open a ring and form a sulfonate anion.

A siloxane skeleton compound or a polyphosphoric acid skeleton compound is a compound having each skeleton and having a group capable of undergoing nucleophilic attack or a group susceptible to nucleophilic attack as a substituent. Examples of groups capable of nucleophilic attack include amino groups, hydroxyl groups, and -SH groups. Examples of the group susceptible to nucleophilic attack include the leaving group, ester group, —COX (X is halogen), — (CO) ₂ O, isocyanate and isothiocyanate described in the previous paragraph.

The siloxane skeleton precursor is a silicon compound that does not have a Si-O-Si bond. For example, the siloxane skeleton precursor is decomposed by reacting with water and condensed with another siloxane skeleton precursor to form a Si-O-Si bond. A compound that can be formed. Examples of the siloxane skeleton precursor include Si (OR) ₄ , RSi (OR) ₃ , and R ₂ Si (OR) ₂ . Note that each R independently represents hydrogen or a hydrocarbon which may have a substituent. Examples of the siloxane skeleton precursor include silane compounds having a group capable of undergoing nucleophilic attack or a group susceptible to nucleophilic reaction as a substituent. Various silane coupling agents may be used as such silane compounds.

  The polyphosphoric acid skeleton precursor is a phosphorus compound that does not have a skeleton of-[P (= O) (OH) -O-] n-. It is a compound that can be condensed with an acid skeleton precursor to form a skeleton with-[P (= O) (OH) -O-] n-. Examples of the polyphosphate skeleton precursor include diphosphorus pentoxide.

  In the synthesis route using the siloxane skeleton precursor or the polyphosphate skeleton precursor, in the final step of synthesizing the zwitterionic compound of the present invention, a Si-OR bond or polyphosphoric acid derived from the siloxane skeleton precursor using a hydrous solvent is used. It is possible to form a structure with a Si—O—Si bond or — [P (═O) (OH) —O—] n— by condensing the PO bond derived from the skeleton precursor while hydrolyzing. preferable. As a water-containing solvent, organic solvents combined with water include methanol, ethanol, propanol, butanol, ethylene glycol, acetone, methyl ethyl ketone, ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, N, N-dimethylformamide, and γ-butyrolactone. Can be illustrated. Moreover, it is preferable to implement the last process on the conditions from which water is removed from a reaction system, such as 100 degreeC or more of manufacturing temperature, or pressure reduction conditions.

From the viewpoint of the production method, as an embodiment of the zwitterionic compound of the present invention, an oligomer or polymer obtained by polycondensing the monomer compounds represented by the general formulas 1-1 to 2-3 is exemplified.
Formula _{1-1: (OR) 3-x} R x Si- (L) n -C ation - (L) n -A nion
Formula _{1-2: (HO) O 4 P} 2 - (L) n -C ation - (L) n -A nion
Formula _{2-1: (OR) 3-x} R x Si- (L) n -A nion - (L) n -C ation
Formula _{2-2: (HO) O 4 P} 2 - (L) n -A nion - (L) n -C ation
Formula _{3-1: A nion - (L)} n - (OR) 2-x R x Si- (L) n -C ation
Formula _{3-2: A nion - (L)} n - (HO) 2 O 3 P 2 - (L) n -C ation
(R each independently represents hydrogen or an _optionally substituted hydrocarbon. _X is 0, 1, 2, or 3. _Cation represents a quaternary ammonium cation. A _nion represents an anion, L independently represents a linker, and the linker is an organic chain which may have a substituent, each n is independently 0 or 1. The linker is together with _Cation . May form a ring.

  The lithium ion conductive material of the present invention contains the zwitterionic compound of the present invention. The lithium ion conductive material of the present invention may be composed of only the zwitterionic compound of the present invention, but may contain impurities and additives within the scope of the present invention. The lithium ion conductive material of the present invention preferably contains 50% by mass or more of the zwitterionic compound of the present invention, more preferably 70% by mass or more of the zwitterionic compound of the present invention, more preferably 90% by mass. What contains the zwitterionic compound of this invention above is further more preferable.

  The lithium ion conductive material of the present invention can be used for various applications by taking advantage of its characteristics. For example, in a power storage device such as a lithium ion secondary battery, use as a protective layer covering the positive electrode, the negative electrode, or the separator, or the separator itself or a solid electrolyte is assumed. Moreover, you may mix | blend the lithium ion conductive material of this invention with the positive electrode active material layer containing the positive electrode active material in a lithium ion secondary battery, or the negative electrode active material layer containing a negative electrode active material. Since the lithium ion conductive material of the present invention is blended in the active material layer, the lithium ion conductive material of the present invention is disposed on at least a part of the surface of the active material. Contact can be reduced.

  Hereinafter, a power storage device comprising the lithium ion conductive material of the present invention, an electrode coated with the lithium ion conductive material of the present invention (hereinafter sometimes referred to as the electrode of the present invention), and the lithium ion conductivity of the present invention. The positive electrode covered with the conductive material will be described.

Examples of the power storage device include a primary battery, a secondary battery, and a capacitor. Hereinafter, the power storage device comprising the lithium ion conductive material of the present invention is referred to as the power storage device of the present invention, the secondary battery comprising the lithium ion conductive material of the present invention is referred to as the secondary battery of the present invention, and the lithium of the present invention. A lithium ion secondary battery having an ion conductive material is sometimes referred to as a lithium ion secondary battery of the present invention.
Hereinafter, the electrode of the present invention and the power storage device of the present invention including the electrode of the present invention will be described through the description of a lithium ion secondary battery which is a typical example of the power storage device.

  The electrode of the present invention may be a positive electrode or a negative electrode. A specific embodiment of the electrode of the present invention includes a current collector, an active material layer formed on the surface of the current collector, and a lithium ion conductive material of the present invention formed on the surface of the active material layer. Layer (hereinafter simply referred to as “lithium ion conductive material layer”).

  A current collector refers to a chemically inert electronic conductor that keeps current flowing through an electrode during discharge or charging of a secondary battery such as a lithium ion secondary battery. The material of the current collector is not particularly limited as long as it is a metal that can withstand a voltage suitable for the active material to be used. The current collector material is at least one selected from silver, copper, gold, aluminum, tungsten, cobalt, zinc, nickel, iron, platinum, tin, indium, titanium, ruthenium, tantalum, chromium, molybdenum, and stainless steel Examples of such a metal material can be given. The current collector may be covered with a known protective layer. What collected the surface of the electrical power collector by the well-known method may be used as an electrical power collector.

  When the potential of the positive electrode is 4 V or more on the basis of lithium, it is preferable to employ aluminum as the positive electrode current collector.

  Specifically, it is preferable to use a positive electrode current collector made of aluminum or an aluminum alloy. Here, aluminum refers to pure aluminum, and aluminum having a purity of 99.0% or more is referred to as pure aluminum. An alloy obtained by adding various elements to pure aluminum is referred to as an aluminum alloy. Examples of the aluminum alloy include Al—Cu, Al—Mn, Al—Fe, Al—Si, Al—Mg, Al—Mg—Si, and Al—Zn—Mg.

  Specific examples of aluminum or aluminum alloy include A1000 series alloys (pure aluminum series) such as JIS A1085 and A1N30, A3000 series alloys (Al-Mn series) such as JIS A3003 and A3004, JIS A8079, A8021, etc. A8000-based alloy (Al-Fe-based).

  The current collector can take the form of a foil, a sheet, a film, a linear shape, a rod shape, a mesh, or the like. Therefore, for example, a metal foil such as a copper foil, a nickel foil, an aluminum foil, and a stainless steel foil can be suitably used as the current collector. When the current collector is in the form of foil, sheet or film, the thickness is preferably in the range of 1 μm to 100 μm.

  The active material layer includes an active material that can occlude and release charge carriers such as lithium ions, and a binder and a conductive aid as necessary. The active material layer preferably contains the active material in an amount of 60 to 99% by mass, more preferably 70 to 95% by mass with respect to the mass of the entire active material layer.

As the positive electrode active material, the general formula of the layered rock salt _{structure: Li a Ni b Co c Mn} d D e O f (0.2 ≦ a ≦ 2, b + c + d + e = 1,0 ≦ e <1, D is W, Mo, Re, Pd, Ba, Cr, B, Sb, Sr, Pb, Ga, Al, Nb, Mg, Ta, Ti, La, Zr, Cu, Ca, Ir, Hf, Rh, Fe, Ge, Zn, Ru, At least one element selected from Sc, Sn, In, Y, Bi, S, Si, Na, K, P, and V, a lithium mixed metal oxide represented by 1.7 ≦ f ≦ 3), Li ₂ MnO ₃ can be mentioned. Further, as a positive electrode active material, a spinel structure metal oxide such as LiMn ₂ O ₄ , a solid solution composed of a mixture of a spinel structure metal oxide and a layered compound, LiMPO ₄ , LiMVO ₄ or Li ₂ MSiO ₄ (wherein M is selected from at least one of Co, Ni, Mn, and Fe). Furthermore, as the positive electrode active material, tavorite compound (the M a transition metal) LiMPO ₄ F, such as LiFePO ₄ F represented by, Limbo ₃ such LiFeBO ₃ (M is a transition metal) include borate-based compound represented by be able to. Any metal oxide used as the positive electrode active material may have the above composition formula as a basic composition, and a metal element contained in the basic composition may be substituted with another metal element. Moreover, you may use as a positive electrode active material the thing which does not contain a charge carrier (for example, lithium ion which contributes to charging / discharging). For example, sulfur alone, compounds in which sulfur and carbon are compounded, metal sulfides such as TiS ₂ , oxides such as V ₂ O ₅ and MnO ₂ , compounds containing polyaniline and anthraquinone, and aromatics in their chemical structures, conjugated two Conjugated materials such as acetic acid organic materials and other known materials can also be used. Further, a compound having a stable radical such as nitroxide, nitronyl nitroxide, galvinoxyl, phenoxyl, etc. may be adopted as the positive electrode active material. When using a positive electrode active material that does not contain a charge carrier such as lithium, it is necessary to add a charge carrier to the positive electrode and / or the negative electrode in advance by a known method. The charge carrier may be added in an ionic state or in a non-ionic state such as a metal. For example, when the charge carrier is lithium, it may be integrated by attaching a lithium foil to the positive electrode and / or the negative electrode.

From the viewpoint of excellent and high capacity, and durability, as the positive electrode active material, the general formula of the layered rock salt _{structure: Li a Ni b Co c Mn} d D e O f (0.2 ≦ a ≦ 2, b + c + d + e = 1,0 ≦ e <1, D is W, Mo, Re, Pd, Ba, Cr, B, Sb, Sr, Pb, Ga, Al, Nb, Mg, Ta, Ti, La, Zr, Cu, Ca, Ir, Hf, At least one element selected from Rh, Fe, Ge, Zn, Ru, Sc, Sn, In, Y, Bi, S, Si, Na, K, P, V, 1.7 ≦ f ≦ 3) It is preferable to employ a lithium composite metal oxide.

  In the above general formula, the values of b, c, and d are not particularly limited as long as the above conditions are satisfied, but those in which 0 <b <1, 0 <c <1, 0 <d <1 are satisfied. And at least one of b, c, and d is in the range of 10/100 <b <90/100, 10/100 <c <90/100, 5/100 <d <70/100. More preferably, the ranges are 20/100 <b <80/100, 12/100 <c <70/100, 10/100 <d <60/100, 30/100 <b <70/100, More preferably, the ranges are 15/100 <c <50/100 and 12/100 <d <50/100.

  About a, e, and f, what is necessary is just a numerical value within the range prescribed | regulated by the said general formula, Preferably 0.5 <= a <= 1.5, 0 <= e <0.2, 1.8 <= f <= 2 0.5, more preferably 0.8 ≦ a ≦ 1.3, 0 ≦ e <0.1, 1.9 ≦ f ≦ 2.1, respectively.

From the viewpoint of excellent and high capacity, and durability, as a positive electrode active material, the _{Li x Mn 2-y A y} O 4 (A spinel structure, Ca, Mg, S, Si , Na, K, Al, P, Ga And at least one element selected from Ge and at least one metal element selected from transition metal elements such as Ni. 0 <x ≦ 2.2, 0 ≦ y ≦ 1). Examples of the value range of x include 0.5 ≦ x ≦ 1.8, 0.7 ≦ x ≦ 1.5, and 0.9 ≦ x ≦ 1.2. The value range of y is 0 ≦ y ≦ 0.8, 0 ≦ y ≦ 0.6 can be exemplified. Specific examples of the spinel structure compound include LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ .

Examples of other specific positive electrode active materials include LiFePO ₄ , Li ₂ FeSiO ₄ , LiCoPO ₄ , Li ₂ CoPO ₄ , Li ₂ MnPO ₄ , Li ₂ MnSiO ₄ , and Li ₂ CoPO ₄ F. As another specific positive electrode active material, Li ₂ MnO ₃ —LiCoO ₂ can be exemplified.

As the negative electrode active material, a material that can occlude and release charge carriers can be used. Therefore, there is no particular limitation as long as it is a simple substance, alloy, or compound that can occlude and release charge carriers such as lithium ions. For example, as a negative electrode active material, Li, group 14 elements such as carbon, silicon, germanium and tin, group 13 elements such as aluminum and indium, group 12 elements such as zinc and cadmium, group 15 elements such as antimony and bismuth, magnesium , Alkaline earth metals such as calcium, and group 11 elements such as silver and gold may be employed alone. Specific examples of the alloy or compound include tin-based materials such as Ag-Sn alloy, Cu-Sn alloy, Co-Sn alloy, carbon-based materials such as various graphites, SiO _x (disproportionated to silicon simple substance and silicon dioxide). Examples thereof include silicon-based materials such as 0.3 ≦ x ≦ 1.6), silicon alone, or composites obtained by combining silicon-based materials and carbon-based materials. In addition, as the negative electrode active material, oxides such as Nb ₂ O ₅ , TiO ₂ , Li ₄ Ti ₅ O ₁₂ , WO ₂ , MoO ₂ , Fe ₂ O ₃ , or Li _3-x M _x N (M = A nitride represented by (Co, Ni, Cu) may be employed. One or more of these materials can be used as the negative electrode active material.

  In view of the possibility of increasing the capacity, preferable negative electrode active materials include graphite, Si-containing materials, and Sn-containing materials.

Specific examples of the Si-containing material include Si alone and SiO _x (0.3 ≦ x ≦ 1.6) disproportionated into two phases of a Si phase and a silicon oxide phase. The Si phase in SiO _x can occlude and release lithium ions, and changes in volume as the secondary battery is charged and discharged. The silicon oxide phase has less volume change associated with charge / discharge than the Si phase. That is, SiO _x as the negative electrode active material realizes a high capacity by the Si phase and suppresses the volume change of the entire negative electrode active material by having the silicon oxide phase. If x is less than the lower limit value, the Si ratio becomes excessive, so that the volume change during charging and discharging becomes too large, and the cycle characteristics of the secondary battery deteriorate. On the other hand, when x exceeds the upper limit value, the Si ratio becomes too small and the energy density decreases. The range of x is more preferably 0.5 ≦ x ≦ 1.5, and further preferably 0.7 ≦ x ≦ 1.2.

In the SiO _x as described above, it is believed to alloying reaction with the silicon lithium and Si phase during charging and discharging of the lithium ion secondary battery may occur. And it is thought that this alloying reaction contributes to charging / discharging of a lithium ion secondary battery. Similarly, it is considered that the Sn-containing material described later can be charged and discharged by an alloying reaction between tin and lithium.

Specific examples of the Sn-containing material include Sn alone, tin alloys such as Cu—Sn and Co—Sn, amorphous tin oxide, and tin silicon oxide. SnB _0.4 P _0.6 O _3.1 can be exemplified as the amorphous tin oxide, and SnSiO ₃ can be exemplified as the tin silicon oxide.

  The Si-containing material and the Sn-containing material are preferably combined with a carbon material to form a negative electrode active material. Due to the composite, the structure of silicon and / or tin is particularly stabilized, and the durability of the negative electrode is improved. The above compounding may be performed by a known method. As the carbon material used for the composite, graphite, hard carbon, soft carbon or the like may be employed. The graphite may be natural graphite or artificial graphite.

  Specific examples of the Si-containing material include a silicon material disclosed in International Publication No. 2014/080608 (hereinafter simply referred to as “silicon material”).

The silicon material has a structure in which a plurality of plate-like silicon bodies are laminated in the thickness direction. For example, the silicon material is subjected to a process of synthesizing a layered silicon compound containing polysilane as a main component by reacting CaSi ₂ with an acid, and further a process of heating the layered silicon compound at 300 ° C. or higher to desorb hydrogen. It is manufactured.

The production method of the silicon material is represented by the following ideal reaction formula when hydrogen chloride is used as the acid.
3CaSi ₂ + 6HCl → Si ₆ H ₆ + 3CaCl ₂
Si ₆ H ₆ → 6Si + 3H ₂ ↑

However, in the upper reaction for synthesizing Si ₆ H ₆ which is polysilane, water is usually used as a reaction solvent from the viewpoint of removing by-products and impurities. Since Si ₆ H ₆ can react with water, in the step of synthesizing the layered silicon compound including the upper reaction, the layered silicon compound is hardly manufactured as containing only Si ₆ H ₆ , and the layered The silicon compound is represented by Si ₆ H _s (OH) _t X _u (X is an element or group derived from an acid anion, s + t + u = 6, 0 <s <6, 0 <t <6, 0 <u <6). Manufactured as a product. In the above chemical formula, inevitable impurities such as Ca that can remain are not taken into consideration. A silicon material obtained by heating the layered silicon compound also contains an element derived from an anion of oxygen or acid.

As described above, the silicon material has a structure in which a plurality of plate-like silicon bodies are laminated in the thickness direction. In order to efficiently store and release charge carriers such as lithium ions, the plate-like silicon body preferably has a thickness in the range of 10 nm to 100 nm, more preferably in the range of 20 nm to 50 nm. The length in the longitudinal direction of the plate-like silicon body is preferably within a range of 0.1 μm to 50 μm. The plate-like silicon body preferably has (length in the longitudinal direction) / (thickness) in the range of 2 to 1000. The laminated structure of the plate-like silicon body can be confirmed by observation with a scanning electron microscope or the like. This laminated structure is considered to be a remnant of the Si layer in the raw material CaSi ₂ .

  The silicon material preferably includes amorphous silicon and / or silicon crystallites. In particular, the above plate-like silicon body is preferably in a state where amorphous silicon is used as a matrix and silicon crystallites are scattered in the matrix. The size of the silicon crystallite is preferably in the range of 0.5 nm to 300 nm, more preferably in the range of 1 nm to 100 nm, still more preferably in the range of 1 nm to 50 nm, and particularly preferably in the range of 1 nm to 10 nm. The size of the silicon crystallite is calculated from the Scherrer equation using X-ray diffraction measurement on the silicon material and using the half-value width of the diffraction peak of the Si (111) plane of the obtained X-ray diffraction chart. .

  The abundance and size of the plate-like silicon body, amorphous silicon and silicon crystallite contained in the silicon material mainly depend on the heating temperature and the heating time. The heating temperature is preferably in the range of 350 ° C to 950 ° C, more preferably in the range of 400 ° C to 900 ° C.

  The silicon material may be coated with carbon. A silicon material coated with carbon is excellent in conductivity.

  The average particle size of the silicon material is preferably in the range of 2 to 7 μm, and more preferably in the range of 2.5 to 6.5 μm. If a silicon material having an average particle size that is too small is used, it may be difficult to manufacture the negative electrode from the viewpoint of cohesion and wettability. Specifically, in the slurry prepared at the time of manufacturing the negative electrode, a silicon material having an average particle size that is too small may aggregate. On the other hand, a lithium ion secondary battery including a negative electrode using a silicon material having an excessively large average particle size may not be able to be charged / discharged appropriately. In the case of a silicon material having an average particle size that is too large, it is presumed that lithium ions cannot sufficiently diffuse into the silicon material. In addition, the average particle diameter in this specification means D50 when a sample is measured with a general laser diffraction type particle size distribution measuring apparatus.

  Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, and carboxymethylcellulose. What is necessary is just to employ | adopt well-known things, such as a styrene butadiene rubber.

  A cross-linked polymer obtained by cross-linking a carboxyl group-containing polymer such as polyacrylic acid or polymethacrylic acid with a polyamine such as diamine disclosed in International Publication No. 2016/063882 may be used as a binder.

  Examples of the diamine used in the crosslinked polymer include alkylene diamines such as ethylene diamine, propylene diamine, and hexamethylene diamine, 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, isophorone diamine, and bis (4-aminocyclohexyl) methane. Saturated carbocyclic diamine, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, bis (4-aminophenyl) sulfone, benzidine, o-tolidine, 2,4- Aromatic diamines such as tolylenediamine, 2,6-tolylenediamine, xylylenediamine, and naphthalenediamine are exemplified.

  The blending ratio of the binder in the active material layer is preferably a mass ratio of active material: binder = 1: 0.005 to 1: 0.3. This is because when the amount of the binder is too small, the moldability of the electrode is lowered, and when the amount of the binder is too large, the energy density of the electrode is lowered.

  The conductive assistant is added to increase the conductivity of the electrode. Therefore, the conductive auxiliary agent may be added arbitrarily when the electrode conductivity is insufficient, and may not be added when the electrode conductivity is sufficiently excellent. The conductive auxiliary agent may be any chemically inert electronic high conductor, and examples thereof include carbon black, graphite, Vapor Grown Carbon Fiber, and various metal particles. The Examples of carbon black include acetylene black, ketjen black (registered trademark), furnace black, and channel black. These conductive assistants can be added to the active material layer alone or in combination of two or more. The blending ratio of the conductive assistant in the active material layer is preferably a mass ratio of active material: conductive assistant = 1: 0.01 to 1: 0.5. This is because if the amount of the conductive auxiliary is too small, an efficient conductive path cannot be formed, and if the amount of the conductive auxiliary is too large, the moldability of the active material layer is deteriorated and the energy density of the electrode is lowered.

  In order to form an active material layer on the surface of the current collector, a current collecting method such as a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, or a curtain coating method can be used. An active material may be applied to the surface of the body. Specifically, an active material, a binder, a solvent, and a conductive additive as necessary are mixed to form a slurry, and the slurry is applied to the surface of the current collector and then dried. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried product may be compressed.

  The lithium ion conductive material layer formed on the surface of the active material layer will be described. Since the lithium ion conductive material layer is formed on the surface of the active material layer, direct contact between the electrolytic solution and the active material can be suppressed, thereby preventing deterioration of the positive electrode active material, the negative electrode active material, or the electrolytic solution. it can. In the case of the positive electrode in which the lithium ion conductive material layer is formed on the surface of the positive electrode active material layer, the oxidative decomposition of the electrolytic solution can be mainly suppressed, and the lithium ion conductive material layer is the negative electrode active material layer. In the case of the negative electrode formed on the surface, reductive decomposition of the electrolytic solution can be mainly suppressed. In particular, the positive electrode of the present invention in which the positive electrode active material layer is coated with a lithium ion conductive material layer can be used under a high potential condition of 4.3 V or higher, 4.5 V or higher, or 4.7 V or higher. is there.

  Although there is no restriction | limiting in particular in the thickness of a lithium ion conductive material layer, 0.01-20 micrometers is preferable, 0.05-15 micrometers is more preferable, 0.1-10 micrometers is further more preferable, and 0.5-5 micrometers is especially preferable.

  In order to provide a lithium ion conductive material layer on the surface of the active material layer, for example, the reaction solution of the final step for synthesizing the zwitterionic compound of the present invention is appropriately prepared to an appropriate concentration, and the surface of the active material layer The drying process may be performed after the coating process of applying to the substrate. In the coating process, a conventionally known method such as a roll coating method, a dip coating method, a doctor blade method, a spray coating method, or a curtain coating method may be used. The drying step may be performed under normal pressure conditions or under reduced pressure conditions using a vacuum dryer. What is necessary is just to set a drying temperature suitably in the range which a lithium ion conductive material does not decompose | disassemble, and the temperature beyond the boiling point of a reaction solvent is preferable. What is necessary is just to set drying time suitably according to an application quantity and drying temperature. The zwitterionic compound of the present invention may be finally synthesized by removing water due to the drying process.

  The secondary battery of the present invention includes the electrode of the present invention. In the secondary battery of the present invention, both the positive electrode and the negative electrode may be the electrode of the present invention, or one of the electrodes is the electrode of the present invention, and the other does not have a lithium ion conductive material layer. A general electrode may be used.

  Specific configurations other than the electrodes in the lithium ion secondary battery of the present invention include a separator and an electrolytic solution.

  The separator separates the positive electrode and the negative electrode and allows lithium ions to pass while preventing a short circuit due to contact between the two electrodes. A known separator may be employed, such as polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamide, polyaramid (Aromatic polyamide), polyester, polyacrylonitrile or other synthetic resin, cellulose, amylose or other polysaccharide, fibroin. And porous materials, nonwoven fabrics, woven fabrics, and the like using one or more electrical insulating materials such as natural polymers such as keratin, lignin, and suberin, and ceramics. The separator may have a multilayer structure.

  The electrolytic solution includes a nonaqueous solvent and an electrolyte dissolved in the nonaqueous solvent.

  As the non-aqueous solvent, cyclic esters, chain esters, ethers and the like can be used. Examples of cyclic esters include ethylene carbonate, propylene carbonate, butylene carbonate, gamma butyrolactone, vinylene carbonate, 2-methyl-gamma butyrolactone, acetyl-gamma butyrolactone, and gamma valerolactone. Examples of chain esters include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, dipropyl carbonate, ethyl methyl carbonate, propionic acid alkyl ester, malonic acid dialkyl ester, and acetic acid alkyl ester. Examples of ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, and 1,2-dibutoxyethane. As the non-aqueous solvent, a compound in which part or all of hydrogen in the chemical structure of the specific solvent is substituted with fluorine may be employed.

Examples of the electrolyte include lithium salts such as LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , and LiN (CF ₃ SO ₂ ) ₂ .

As an electrolytic solution, 0.5 mol / liter of a lithium salt such as LiClO ₄ , LiPF ₆ , LiBF ₄ , LiCF ₃ SO _{3 is} added to a non-aqueous solvent such as fluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. A solution dissolved at a concentration of about 1.7 mol / L from L can be exemplified.

A specific method for producing the lithium ion secondary battery of the present invention will be described.
For example, a separator is sandwiched between a positive electrode and a negative electrode to form an electrode body. The electrode body may be any of a stacked type in which a positive electrode, a separator and a negative electrode are stacked, or a wound type in which a positive electrode, a separator and a negative electrode are stacked. After connecting the positive electrode current collector and the negative electrode current collector to the positive electrode terminal and the negative electrode terminal connected to the outside using a current collecting lead or the like, an electrolyte is added to the electrode body to form a lithium ion secondary battery. Good.

  The shape of the lithium ion secondary battery of the present invention is not particularly limited, and various shapes such as a cylindrical shape, a square shape, a coin shape, and a laminate shape can be adopted.

  The lithium ion secondary battery of the present invention may be mounted on a vehicle. The vehicle may be a vehicle that uses electric energy generated by a lithium ion secondary battery for all or a part of its power source. For example, the vehicle may be an electric vehicle or a hybrid vehicle. When a lithium ion secondary battery is mounted on a vehicle, a plurality of lithium ion secondary batteries may be connected in series to form an assembled battery. Examples of devices equipped with lithium ion secondary batteries include various home appliances driven by batteries such as personal computers and portable communication devices, office devices, and industrial devices in addition to vehicles. Furthermore, the lithium ion secondary battery of the present invention includes wind power generation, solar power generation, hydroelectric power generation and other power system power storage devices and power smoothing devices, power supplies for ships and / or auxiliary power supply sources, aircraft, Power supply for spacecraft and / or auxiliary equipment, auxiliary power supply for vehicles that do not use electricity as a power source, power supply for mobile home robots, power supply for system backup, power supply for uninterruptible power supply, You may use for the electrical storage apparatus which stores temporarily the electric power required for charge in the charging station for electric vehicles.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited by these Examples.

Example 1
0.681 g (10 mmol) of imidazole was dissolved in 5 mL of dichloromethane to prepare an imidazole solution. The above-mentioned imidazole solution was added dropwise to a solution of 1.362 g (10 mmol) of 2,4-butane sultone dissolved in 5 mL of dichloromethane at room temperature and under stirring conditions, and the resulting reaction solution was stirred for 12 hours to prepare reaction solution A. Manufactured. Dichloromethane was distilled off from the reaction solution A to obtain a solid intermediate A. The infrared absorption spectrum of Intermediate A is shown in FIG. Intermediate A was deliquescent.

  A reaction formula in which imidazole and 2,4-butane sultone react to obtain intermediate A is shown below.

  0.204 g (1 mmol) of Intermediate A was dissolved in 10 mL of 95% ethanol, 0.208 g (1 mmol) of tetraethoxysilane was further added, and the mixture was stirred at room temperature for 6 hours to obtain Reaction Solution 1. .

The reaction solution 1 was applied to the surface of the aluminum foil in a film form, and then heated at 120 ° C. for 2 hours to remove the solvent containing water, thereby producing the film-form lithium ion conductive material of Example 1. . The infrared absorption spectrum of the lithium ion conductive material of Example 1 is shown in FIG. From the infrared absorption spectrum of FIG. 2, a peak considered to be derived from the Si—N bond was observed in the vicinity of 930 cm ⁻¹ .

In the reaction in which the intermediate A reacts with tetraethoxysilane and water further reacts and then ethanol and water are distilled off to obtain the lithium ion conductive material of Example 1, One is shown below. In the following reaction formula, R is H, C ₂ H ₅ or Si, and n is an integer of 2 or more.

<Manufacture of positive electrode and lithium ion secondary battery>
Using the reaction solution 1, the positive electrode of Example 1 coated with the lithium ion conductive material of Example 1 and the lithium ion secondary battery of Example 1 including the lithium ion conductive material of Example 1 were used. Produced as follows.

1.8 parts by mass of spinel-structured LiMn _1.5 Ni _0.5 O ₄ as a positive electrode active material, 0.1 parts by mass of acetylene black as a conductive additive, and 8% by mass of polyvinylidene fluoride as a binder The slurry containing N-methyl-2-pyrrolidone solution containing 1.25 parts by mass and an appropriate amount of N-methyl-2-pyrrolidone was prepared. An aluminum foil having a thickness of 15 μm was prepared as a positive electrode current collector. The slurry was applied in a film form on the surface of the aluminum foil. The aluminum foil coated with the slurry was dried to remove N-methyl-2-pyrrolidone. Thereafter, the aluminum foil was pressed to obtain a bonded product. The obtained joined product was heated and dried with a drier to produce a positive electrode precursor made of an aluminum foil on which a positive electrode active material layer was formed. The thickness of the positive electrode precursor was 35 μm.

  The reaction solution 1 was applied in a film shape with a thickness of 50 μm on the surface of the positive electrode active material layer in the positive electrode precursor, and then heated at 120 ° C. for 2 hours to remove the solvent containing water, thereby removing the lithium ion of Example 1 A positive electrode of Example 1 coated with a conductive material was produced.

The positive electrode of Example 1 was cut into a diameter of 15 mm and used as an evaluation electrode. A metal lithium foil having a thickness of 500 μm was cut into a diameter of 16 mm to obtain a counter electrode. As a separator, a glass filter (Hoechst Celanese) and celgard 2400 (Polypore Corporation), which is a single-layer polypropylene, were prepared. It was also prepared an electrolyte solution obtained by dissolving LiPF ₆ at 1 mol / L in a solvent obtained by mixing 50 parts by volume of ethylene carbonate and diethyl carbonate 50 parts by volume. Two kinds of separators were sandwiched between the counter electrode and the evaluation electrode in the order of the counter electrode, the glass filter, celgard 2400, and the evaluation electrode, thereby forming an electrode body. This electrode body was housed in a coin-type battery case CR2032 (Hosen Co., Ltd.), and after the electrolyte was injected, the battery case was sealed to manufacture a coin-type battery. This was designated as the lithium ion secondary battery of Example 1.

(Example 2)
Intermediate A was produced in the same manner as in Example 1. 0.408 g (2 mmol) of Intermediate A was dissolved in 10 mL of 95% ethanol, 0.208 g (1 mmol) of tetraethoxysilane was further added, and the mixture was stirred at room temperature for 6 hours to obtain Reaction Solution 2. .
The positive electrode of Example 2 coated with the lithium ion conductive material of Example 2 and of Example 2 were used in the same manner as in Example 1, except that reaction solution 2 was used instead of reaction solution 1. A lithium ion secondary battery of Example 2 including a lithium ion conductive material was manufactured.

(Example 3)
Intermediate A was produced in the same manner as in Example 1. 0.408 g (2 mmol) of Intermediate A was dissolved in 10 mL of 95% ethanol and cooled to 0 ° C. To this solution, 0.284 g (1 mmol) of diphosphorus pentoxide was added and stirred at room temperature for 6 hours to obtain Reaction Solution 3.
The positive electrode of Example 3 and the positive electrode of Example 3 coated with the lithium ion conductive material of Example 3 were used in the same manner as in Example 1, except that reaction liquid 3 was used instead of reaction liquid 1. A lithium ion secondary battery of Example 3 comprising a lithium ion conductive material was manufactured.

  In the reaction in which the intermediate A and diphosphorus pentoxide are reacted and water is distilled off to obtain the lithium ion conductive material of Example 3, one of the assumed reaction formulas is shown below. In the following reaction formula, n is an integer of 2 or more.

Example 4
Intermediate A was produced in the same manner as in Example 1. Dissolve 0.816 g (4 mmol) of Intermediate A in 10 mL of 95% ethanol, add 0.284 g (1 mmol) of diphosphorus pentoxide, and stir at room temperature for 6 hours to obtain Reaction Solution 4. It was.
The positive electrode of Example 4 coated with the lithium ion conductive material of Example 4 and the positive electrode of Example 4 were used in the same manner as in Example 1 except that reaction liquid 4 was used instead of reaction liquid 1. A lithium ion secondary battery of Example 4 comprising a lithium ion conductive material was manufactured.

(Example 5)
0.681 g (10 mmol) of imidazole was dissolved in 5 mL of dichloromethane to prepare an imidazole solution. Under stirring conditions, the above imidazole solution was added dropwise at room temperature to a solution of 2.363 g (10 mmol) of 3-glycidyloxypropyltrimethoxysilane in 5 mL of dichloromethane, and the resulting reaction solution was stirred for 6 hours. Reaction liquid 5-1 was manufactured.

  A 2,4-butane sultone solution was prepared by dissolving 1.362 g (10 mmol) of 2,4-butane sultone in 5 mL of dichloromethane. Under stirring conditions, a 2,4-butane sultone solution was added dropwise to the reaction solution 5-1 at room temperature, and the resulting reaction solution was stirred for 12 hours to produce a reaction solution 5-2. Dichloromethane was distilled off from the reaction solution 5-2 to obtain an intermediate 5.

  A reaction formula in which intermediate 5 is obtained by the reaction of 3-glycidyloxypropyltrimethoxysilane, imidazole, and 2,4-butanesultone is shown below.

  Intermediate 5 was dissolved in 95% ethanol to obtain an intermediate 5 solution. The positive electrode of Example 5 coated with the lithium ion conductive material of Example 5 and Example 5 in the same manner as in Example 1 except that the intermediate 5 solution was used instead of the reaction solution 1. The lithium ion secondary battery of Example 5 which comprises the lithium ion conductive material of was manufactured.

(Example 6)
0.681 g (10 mmol) of imidazole was dissolved in 5 mL of dichloromethane to prepare an imidazole solution. Under stirring conditions, to a solution of 2.053 g (10 mmol) of 3- (trimethoxysilyl) propyl isocyanate in 5 mL of dichloromethane, the imidazole solution was added dropwise at room temperature, and the resulting reaction liquid was stirred for 12 hours. Thus, a reaction solution 6-1 was produced.

  A 2,4-butane sultone solution was prepared by dissolving 1.362 g (10 mmol) of 2,4-butane sultone in 5 mL of dichloromethane. Under stirring conditions, a 2,4-butane sultone solution was added dropwise to the reaction solution 6-1 at room temperature, and the resulting reaction solution was stirred for 12 hours to produce a reaction solution 6-2. Dichloromethane was distilled off from the reaction solution 6-2 to obtain an intermediate 6.

  A reaction formula in which 3- (trimethoxysilyl) propyl isocyanate, imidazole, and 2,4-butane sultone react to obtain intermediate 6 is shown below.

  Intermediate 6 was dissolved in 95% ethanol to obtain an intermediate 6 solution. The positive electrode of Example 6 coated with the lithium ion conductive material of Example 6 and Example 6 were prepared in the same manner as in Example 1 except that the intermediate 6 solution was used instead of reaction solution 1. A lithium ion secondary battery of Example 6 comprising the lithium ion conductive material was manufactured.

(Example 7)
0.88 g (10 mmol) of N, N-dimethylethylenediamine was dissolved in 5 mL of dichloromethane to prepare an N, N-dimethylethylenediamine solution. Under stirring conditions, the above N, N-dimethylethylenediamine solution was added dropwise at room temperature to a solution of 2.053 g (10 mmol) of 3- (trimethoxysilyl) propyl isocyanate dissolved in 5 mL of dichloromethane. The liquid was stirred for 12 hours to produce a reaction liquid 7-1.

  A 2,4-butane sultone solution was prepared by dissolving 1.362 g (10 mmol) of 2,4-butane sultone in 5 mL of dichloromethane. Under stirring conditions, a 2,4-butane sultone solution was added dropwise to the reaction solution 7-1 at room temperature, and the resulting reaction solution was stirred for 12 hours to produce a reaction solution 7-2. Dichloromethane was distilled off from the reaction solution 7-2 to obtain an intermediate 7.

  A reaction formula in which intermediate 7 is obtained by the reaction of 3- (trimethoxysilyl) propyl isocyanate, N, N-dimethylethylenediamine, and 2,4-butanesultone is shown below.

  Intermediate 7 was dissolved in 95% ethanol to obtain an intermediate 7 solution. The positive electrode of Example 7 coated with the lithium ion conductive material of Example 7 and Example 7 in the same manner as in Example 1 except that the Intermediate 7 solution was used instead of Reaction Solution 1. A lithium ion secondary battery of Example 7 comprising the lithium ion conductive material was manufactured.

(Comparative Example 1)
A lithium ion secondary battery of Comparative Example 1 was produced in the same manner as in Example 1 except that the positive electrode precursor described in Example 1 was used as the positive electrode of Comparative Example 1 as it was and used as an evaluation electrode.

(Comparative Example 2)
An intermediate A solution was prepared by dissolving 0.408 g (2 mmol) of intermediate A in 10 mL of 95% ethanol. A positive electrode and a lithium ion secondary battery of Comparative Example 2 were produced in the same manner as in Example 1 except that the intermediate A solution was used instead of the reaction solution 1.

(Comparative Example 3)
A tetraethoxysilane solution was prepared by dissolving 0.208 g (1 mmol) of tetraethoxysilane in 10 mL of 95% ethanol. A positive electrode and a lithium ion secondary battery of Comparative Example 3 were produced in the same manner as in Example 1 except that a tetraethoxysilane solution was used instead of the reaction solution 1.

(Comparative Example 4)
A solution was prepared by dissolving 0.284 g (1 mmol) of diphosphorus pentoxide in 10 mL of 95% ethanol. A positive electrode and a lithium ion secondary battery of Comparative Example 4 were produced in the same manner as in Example 1 except that the solution was used instead of the reaction solution 1.

(Evaluation example 1)
Each lithium ion secondary battery was charged to 4.9 V at a constant current of 0.05 C rate, and then discharged to 3.5 V at a constant current of 0.05 C rate (hereinafter referred to as initial charge / discharge). ). The initial efficiency was calculated according to the following formula.
Initial efficiency (%) = 100 × (discharge capacity) / (charge capacity)

Next, each lithium ion secondary battery after the initial charge / discharge was charged to 4.9 V at a constant current of 0.05 C, and then discharged to 3.5 V at a constant current of 0.5 C. . The rate characteristics were calculated according to the following formula.
Rate characteristic (%) = 100 × (discharge capacity at 0.5 C rate) / (discharge capacity at 0.05 C rate)

Further, each lithium ion secondary battery after the initial charge / discharge was charged to 4.9 V at a constant current of 0.05 C, and then discharged to 3.5 V at a constant current of 0.05 C. Thereafter, a charge / discharge cycle of charging to 4.9 V with a constant current of 0.3 C rate and then discharging to 3.5 V with a constant current of 0.3 C rate was repeated 20 times. The capacity retention rate was calculated according to the following formula.
Capacity maintenance rate (%) = 100 × (discharge capacity at 20th cycle) / (discharge capacity at 1st cycle)

  The test results are shown in Table 1.

The meanings of the abbreviations in Table 1 are as follows.
TEOS: Tetraethoxysilane

  From the results of Table 1, it was confirmed that all of the lithium ion secondary batteries of the examples including the lithium ion conductive materials of the examples were suitably charged and discharged. From this result, it can be said that the lithium ion conductive material of the example suitably supported lithium ions. Moreover, it can be said that the lithium ion secondary battery of an Example showed the battery characteristic of the same grade or more compared with the lithium ion secondary battery of a comparative example.

Claims (6)

  A zwitterionic compound comprising a quaternary ammonium cation, an anion, and a siloxane skeleton or a polyphosphate skeleton. The zwitterionic compound according to claim 1, which has a structure represented by any one of the following general formulas 1 to 3.
General formula 1: _Skeleton- (L) _{n- Cation-} (L) _n - _Anion
General formula 2: _Skeleton- (L) _n - _Anion- (L) _{n- Cation}
General formula 3: _Anion- (L) _n- S _kelton- (L) _{n- Cation
(S} keleton is _{.C ation} which means a siloxane skeleton or polyphosphoric acid skeleton means a linker each .L independently _{.A nion} to mean quaternary ammonium cation to mean anions, linker have a substituent And n is independently 0 or 1. The linker may form a ring together with _Skeleton and / or _Cation .)   The zwitterionic compound according to claim 1 or 2, wherein the anion is a sulfonate anion, a carboxylate anion, a phosphonate anion, or a phosphate anion.   The lithium ion conductive material containing the zwitterionic compound of any one of Claims 1-3.   A power storage device comprising the lithium ion conductive material according to claim 4. An electrode coated with the lithium ion conductive material according to claim 4.

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