JP5573749B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a highly durable nonaqueous electrolyte battery.

  A conventional non-aqueous electrolyte secondary battery has an active material that can exchange metal ions such as lithium as an electrode.

  By the way, a radical material may be included in the positive electrode for the purpose of improving the battery capacity. The radical material contained in the positive electrode can contribute to the battery reaction. Furthermore, an air battery is known in which oxygen in the air is used as a positive electrode active material, and a redox catalyst that catalyzes a redox reaction of oxygen is included in the positive electrode. It is disclosed that a radical material is suitable as the redox catalyst (Patent Document 1).

JP 2009-259664 A

  By the way, according to a study by the present inventors, a non-aqueous secondary battery in which a radical material is contained in the positive electrode may not show sufficient durability. As a result of intensive studies by the present inventors to find out the cause, it has become clear that the radical material contained may be deactivated depending on the type of the supporting salt contained in the electrolyte. Specifically, it has been found that the radicals possessed by the radical material are deactivated by the Lewis acid that is contained in the battery in advance or generated during storage, and the battery performance decreases. As will be described in detail in Examples, it has been found that Lewis acid has a function of consuming radicals by forming a complex with a radical material, thereby preventing the radical of the radical material from participating in the battery reaction.

  This invention is completed in view of the said situation, and makes it the subject which should be solved to provide the nonaqueous electrolyte battery excellent in durability.

Based on the above findings, the present inventors have completed the following invention. That is, the invention according to claim 1 that solves the above-described problem includes a positive electrode having a radical material,
A negative electrode capable of inserting or extracting metal ions (M ions; M is selected from the group consisting of Li, Na, K, Ca, Mg, Zn, Fe, and Al);
A non-aqueous electrolyte interposed between the positive electrode and the negative electrode ;
A battery having
The non-aqueous electrolyte is Me _a X _b (Me is selected from the group consisting of Li, Na, K, Ca, and Al; X is a bis (oxalate) borate anion, malonato- Selected from the group consisting of an oxalatoborate (malonato-oxalatoborate) anion and a bis (malonato) borate anion; a and b are determined from 1 to 3 depending on the oxidation number of Me A non-aqueous electrolyte battery comprising a supporting salt comprising an integer).

  The durability of the nonaqueous electrolyte battery can be improved by employing the above-described supporting salt. The reason for this is considered that these supporting salts can exhibit an action as an electrolyte without deactivating radicals of the radical material in the atmosphere in the battery.

The invention of claim 1 for solving the above-mentioned problems, further, a non-aqueous electrolyte battery, wherein the pre-SL has no free Lewis acid to contact the radical material.

Moreover, invention of Claim 2 which solves the said subject is the compound group A which the said Lewis acid shows below .

The compound group A includes AsF ₅ , AgF, AgBF ₄ , BH ₃ , B ₂ H ₆ , CaCl ₂ , (Cp) ₂ Os, (Cp) ₂ Ru, CuCl ₂ , Cu (BF ₄ ) ₂ , GaCl ₃ , GaF ₃ , Ga ₂ H ₆ , GeF ₄ , GeH ₄ , H ₂ SO ₄ , HCOOH, HCN, HF, HCl, HBr, HI, Mg (CH ₂ SCH ₃ ) ₂ , MnCl ₂ , MoF ₆ , NaBF ₄ , NaB (C ₆ H ₅ ) ₄ , NbCl ₅ , NH ₄ [B (C ₆ H ₅ ) ₃ CH ₃ ], NH ₄ PF ₆ , NO ₂ (SbF ₆ ), NO (SbCl ₆ ), NO ₂ (BF ₄ ) _{, PF 3, PF 5, Pd} (CN) 2, PtCl 4, PtI 4, SbCl 3, SbF 6, SiCl 4, SiF4, SF 4, SnH 4, SO 3, TiCl 3, WF _{, ZrCl 4, BX 3, AlX} 3, SnX 2, SnX 4, MgX 2, TiX 4, PdX 2, CrX 3, FeX 3, CoX 3, NiX 2, SbX 5, InX 3, ZnX 2 (X is F ^- , Cl ⁻ , Br ⁻ , I ⁻ , CF ₃ SO ₃ ⁻ , C ₆ F ₅ ⁻ , C ₆ H ₅ ⁻ , OCH ₂ CH ₃ ^— ), Ho (CF ₃ SO ₃ ) ₂ , Ca (CF ₃ SO ₃ ) ₂ , Sc (CF ₃ SO ₃ ) ₃ , Y (CF ₃ SO ₃ ) ₃ , Ln (CF ₃ SO ₃ ) ₃ (Ln is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd , Tb, Dy, Ho, Er, Tm, Yb, or Lu), BF ₃ -diethyl etherate complex, BF ₃ -acetic acid complex, BF ₃ -methyl-t-butyl ether complex, BF ₃ -di-n-butyl ether Rate complex , BF ₃ - dimethyl etherate complex, BF ₃ - dimethyl sulfide complex, BF ₃ - phenol complex, BF ₃ - phosphate complex, BF ₃ - tetrahydrofuran complex, triflic acid, tributyl borane, tributyl borate, and tris (perfluorophenyl ) A group of boranes.

The deactivation of the radical material can be prevented by not containing and forming a Lewis acid (particularly the compound group A as described in claim 2) so as to come into contact with the radical material. Here, the above-mentioned compound does not contain or does not form means 0.1 M or less on the basis of the concentration of the supporting salt in the electrolyte (more preferably, 0.05 M or less, 0.001 M or less, 0.0001 M or less, detection The range below or below the limit can also be selected). Moreover, the said Lewis acid and the compound group A may be contained if it is a site | part which does not contact radical material. For example, it does not prevent the compound described above from being contained in a space completely separated so as not to contact the radical material present in the positive electrode or outside the battery.

According to a third aspect of the present invention, the radical material is a nitroxyl radical compound.

  The battery capacity can be improved by containing the nitroxyl radical in the positive electrode.

The invention according to claim 4 is characterized in that the non-aqueous electrolyte is ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyl lactone, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, 1,2-dimethoxyethane, methyl acetate, tetrahydrofuran. 1 or 2 selected from the group consisting of 2-methyltetrahydrofuran 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, 3-methyloxazolidinone, methyl sulfolane formate, dimethyl sulfoxide, and acetonitrile The above non-aqueous solvent is included.

  These non-aqueous solvents do not generate a Lewis acid under the atmosphere in the battery and do not cause deactivation of the radical material.

According to a fifth aspect of the present invention, the one surface side of the positive electrode has an oxygen permeable film in contact with the oxygen-containing gas, and the radical material is disposed on the other surface side of the oxygen permeable film.

  Since oxygen is used as the positive electrode active material, the energy density of the battery can be improved.

4 is a diagram showing a cyclic voltammogram in the test solution of Test Example 1. FIG. 4 is a diagram showing a cyclic voltammogram in a test solution of Test Example 2. FIG. FIG. 6 is a diagram showing a cyclic voltammogram in the test solution of Test Example 3. It is a schematic diagram which shows the mode of interaction of radical material and a Lewis acid.

  The nonaqueous electrolyte battery of the present invention will be described in detail based on the embodiment.

(Nonaqueous electrolyte battery)
The nonaqueous electrolyte battery of the present invention has a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode has a radical material. The negative electrode has a configuration capable of inserting or extracting metal ions. The metal ions are Li, Na, K, Ca, Mg, Zn, Fe, or Al ions.

  The form of the nonaqueous electrolyte battery of the present embodiment is not particularly limited, and a positive electrode, a negative electrode, and an electrolyte are formed into a sheet shape, and the wound type battery that is wound after being stacked, the laminated type battery that is laminated, and the like The usual form of can be adopted. Although the form of a positive electrode, a negative electrode, and electrolyte is not specifically limited, A sheet form and a plate form can be illustrated, respectively. In addition, when employ | adopting the form using oxygen in a positive electrode, oxygen-containing gas (air etc.) can be supplied to the positive electrode side. Further, the non-aqueous electrolyte battery of the present embodiment may be either a primary battery or a secondary battery, and it is possible to suppress deterioration of battery performance during storage in the primary battery and the secondary battery, and to be adopted for the secondary battery. Then, the invention can contribute to the maintenance of cycle characteristics.

  The nonaqueous electrolyte battery of this embodiment employs at least one of the following configurations (a) to (c). High durability is realizable by employ | adopting 1 or 2 or more of these structures. In addition, when employ | adopting the structure of (a), it is desirable not to employ | adopt support salts other than this support salt.

(A) The non-aqueous electrolyte is Me _a X _b (Me is selected from the group consisting of Li, Na, K, Ca, and Al; X is bis (oxalate) borate (BOB) An anion, malonato-oxalatoborate (MOB) anion, and bis (malonato) borate (BMB) anion are selected; a and b depend on the oxidation number of Me A supporting salt consisting of an integer determined from 1 to 3). Me can select the thing corresponding to the metal ion occluded thru | or discharge | released in the positive / negative electrode mentioned later.
(B) It does not contain a Lewis acid so as to come into contact with the radical material contained in the positive electrode described later, and no Lewis acid is produced so as to come into contact with the radical material when the battery is held at 60 ° C. for 12 days. about. Here, producing | generating by 60 degreeC and holding | maintenance for 12 days does not include the case where it produces | generates on conditions exceeding 60 degreeC or more than 12 days, and satisfy | fills this requirement (b). On the other hand, when a Lewis acid is produced under milder conditions, this requirement (b) is not satisfied as a Lewis acid is produced. That is, this requirement (b) is not satisfied when the Lewis acid is generated at a temperature of less than 60 ° C. or less than 12 days.
(C) The compound group which does not include the above-described compound group A so as to come into contact with the radical material contained in the positive electrode, which will be described later, and comes into contact with the radical material when the battery is held at 60 ° C. for 12 days. A is not generated. Here, producing | generating by 60 degreeC and holding | maintenance for 12 days does not include the case where it produces | generates on the conditions over 60 degreeC or over 12 days, and satisfy | fills this requirement (c). On the other hand, when the compound group A is produced under milder conditions, this requirement (c) is not satisfied as the compound group A is generated. That is, this requirement (c) is not satisfied when the compound group A is produced at a temperature of less than 60 ° C. or less than 12 days.
-Positive electrode In addition to a radical material, a positive electrode can have the positive electrode active material which can occlude or discharge | release the metal ion which a negative electrode occludes or discharge | releases. When there is no positive electrode active material, oxygen present outside is used as the positive electrode active material, so that an oxygen permeable membrane capable of taking in oxygen from the outside can be provided on the positive electrode. As the oxygen permeable membrane, an oxygen-enriched membrane that selectively permeates oxygen, a porous material (including stainless steel, nickel, aluminum, copper, etc.) that communicates with the front and back surfaces, a net, a punching metal, and the like can be used. It is desirable that the oxygen permeable membrane also serves as a current collector. It is desirable to adopt a form filled with a radical material or the like in the pores of the porous material, the net, the holes of the punching metal, and the like.

  Although it does not specifically limit as a radical material, The thing which can exist stably in a battery atmosphere is desirable. Here, the radical that can exist stably is one in which the radical structure can be maintained even after a long period of time, and the presence of the radical can be measured by ESR.

  Examples of the radical material include compounds having the following radical skeleton. The chemical structure of the portion other than the radical skeleton is not particularly limited as long as the radical becomes stable, whether or not it interacts electronically with the radical. For example, the radical skeleton can be bonded to some polymer compound.

  Examples of the radical skeleton that can be employed are shown below. For example, those selected from the group consisting of a skeleton having a nitroxyl radical, a skeleton having an oxy radical, a skeleton having a nitrogen radical, a skeleton having a sulfur radical, a skeleton having a carbon radical, and a skeleton having a boron radical are preferable. Specifically, a skeleton having a nitroxyl radical as shown in formulas (1) to (9), a skeleton having a phenoxy radical (oxy radical) as shown in formula (10), and formulas (11) to (13) And a skeleton having a hydrazyl radical (nitrogen radical), a skeleton having a carbon radical as shown in formulas (14) and (15), and the like. Among these, a skeleton having a nitroxyl radical is particularly preferable. For example, a 2,2,6,6-tetraalkyl-1-oxylpiperidinyl skeleton (see formula (1): 2,2,6,6-tetramethyl) -1-piperidinyloxy (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (4-hydroxy-TEMPO), 3-carbamoyl-2,2,5,5-tetra Methylpyrrolidine-1-yloxy (3-carbamoyl-PROXYL), or 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (3-carboxy-PROXYL), 2,2, 5,5-tetraalkyl-1-oxylpyrrolinyl skeleton (see formula (2)) and 2,2,5,5-tetraalkyl-1-oxylpyrrolidinyl skeleton (formula ( ) Those selected from the group consisting of the reference) is preferred. These skeletons may be bonded to the polymer compound as they are or through any atom of the skeleton. Examples of the polymer compound include poly (meth) acrylic acid alkyl ester, polyacrylonitrile, polyolefin, polystyrene, polyaniline, and polypyrrole.

    These skeletons may be used as they are, or may be used as polymer compounds bonded to the polymer compound via any atom of the skeleton. Examples of the polymer compound include compounds in which the above skeleton is bonded to poly (meth) acrylic acid alkyl ester, polyacrylonitrile, polyolefin, polystyrene, polyaniline, polypyrrole, and the like.

  The radical material may be a compound having a structure in which a stable radical skeleton as described above is linked to a polycyclic aromatic ring. As the polycyclic aromatic ring, for example, those selected from the group consisting of naphthalene, phenalene, triphenylene, anthracene, perylene, phenanthrene, and pyrene are preferable, and pyrene is particularly preferable. The polycyclic aromatic ring is a member selected from the group consisting of an amide bond, an ester bond, a urea bond, a urethane bond, a carbamide bond, an ether bond, and a sulfide bond, and is connected to the radical skeleton through the spacer. You may do it.

  The polycyclic aromatic ring may be directly connected to the radical skeleton without using such a spacer, but it is preferable that the polycyclic aromatic ring is connected to the radical skeleton through such a spacer because synthesis is easy. Further, an alkylene chain may exist between the polycyclic aromatic ring and the spacer, or an alkylene chain may exist between the radical skeleton and the spacer. Only one polycyclic aromatic ring may be connected to one radical skeleton, or a plurality of polycyclic aromatic rings may be connected. In that case, all of the plurality of polycyclic aromatic rings may be the same or different, or some may be the same and others may be different. Alternatively, one polycyclic aromatic ring may be connected to a plurality of radical skeletons. In that case, all of the plurality of radical skeletons may be the same or different, or some may be the same and others may be different. The radical skeleton may have one radical in the skeleton or may have a plurality of radicals.

  The positive electrode may have a radical material supported on a carrier. Examples of the carrier include a carbon material. The carbon material may be carbon blacks such as ketjen black, acetylene black, channel black, furnace black, lamp black, thermal black and the like, or natural graphite such as flake graphite, graphite such as artificial graphite and expanded graphite. However, it may be activated carbon made from charcoal or coal, carbon fibers made from carbonized synthetic fibers or petroleum pitch-based materials, molecular carbons like fullerenes, carbon nanotubes, etc. It is good also as tube-like carbons. Further, in the positive electrode, the radical material described above is 0.01 relative to the total mass of the positive electrode (which may be the mass including the current collector, but is preferably based on the mass excluding the current collector). It is preferable to occupy ˜60% by mass, more preferably occupy 55% by mass or less, and further preferably occupy 0.01 to 50% by mass. By containing 0.01% by mass or more, the effect of the catalyst can be sufficiently obtained, and when it is 60% by mass or less, other components (conductive material, binder, etc.) contained in the positive electrode are relatively low. Therefore, the electrical conductivity and mechanical strength can be sufficiently maintained. Such carbon may also serve as a conductive material described later.

  The radical material is preferably supported on a single molecule on a carrier. Here, “single molecule support” means that the radical material is not aggregated but is supported on the carrier in a dispersed state to a single molecule state. All the molecules of the radical material may be supported by a single molecule, or a part of the molecules may be supported by a single molecule. In addition, it is more preferable that more radical materials carry a single molecule from the viewpoint of exhibiting a catalytic function.

  This radical material is preferably carried on a carrier after being subjected to a treatment of irradiating ultrasonic waves. The ultrasonic treatment may be a treatment in which, after preparing a mixed solution in which a radical material, a carrier, and an appropriate solvent are mixed, this mixed solution is irradiated with ultrasonic waves using an ultrasonic generator. The radical material supported on the carrier can be obtained from this mixed solution by filtering or spray drying. This mixed solution preferably contains 10% by mass to 50% by mass of the radical material by mass with respect to the carrier. As the solvent, an organic solvent such as acetone or alcohol is preferably used. The irradiation time of ultrasonic waves can be, for example, 1 hour or more and 10 hours or less. This single molecule-supported radical material is preferably a compound having a structure in which a polycyclic aromatic ring is linked to a stable radical skeleton, and the carrier is preferably a carbon material having a cyclic structure, and has a π bond. What has is more preferable. In this way, the radical material is sufficiently supported on the carrier by the π-π interaction between the polycyclic aromatic ring contained in the radical material and the carbonaceous ring structure of the carrier, so that it is easy to carry a single molecule. Therefore, it is preferable. In this case, the radical material preferably includes a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyrene ring and the like as a polycyclic aromatic ring, and particularly preferably includes a pyrene ring. As the carrier, carbon blacks, graphites, tubular carbons and the like are preferable as carbon materials having a cyclic structure.

  The positive electrode may contain a conductive material. The conductive material is not particularly limited as long as it is a conductive material. For example, the above-described carbon blacks, graphites, activated carbons, or carbon fibers may be used. Further, conductive fibers such as metal fibers, metal powders made of copper, silver, nickel, aluminum, or the like, or organic conductive materials such as polyphenylene derivatives may be used. These may be used alone or in combination.

  The positive electrode may contain a binder. Although it does not specifically limit as a binder, A thermoplastic resin, a thermosetting resin, etc. are mentioned. For example, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, tetrafluoroethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin) , Polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrif Examples include olefin copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, and ethylene-acrylic acid copolymer. . These materials may be used alone or in combination.

  The positive electrode may be formed by mixing a positive electrode active material, a carrier, a conductive material, and a binder, which are added as necessary, in addition to the radical material, and then press-molding the current collector. As the current collector, a porous body such as a net or mesh is preferably used in order to allow oxygen to diffuse quickly, and a porous metal plate such as stainless steel, nickel, aluminum, or copper can be used. The current collector may be coated with an oxidation-resistant metal or alloy film on its surface in order to suppress oxidation.

  The active material that can be contained in the positive electrode can be composed of one or more materials selected from the group consisting of an oxide positive active material, an organic positive active material, and an inorganic positive active material. .

The active material employ | adopted for the battery using lithium ion as a metal ion is illustrated below. Examples of the oxide-type positive electrode active material include LiNiO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , and LiFePO ₄ . Examples of the oxide-type positive electrode active material include Li _(1-x) MnO ₂ , Li _(1-x) Mn ₂ O ₄ , Li _(1-x) CoO ₂ , Li _(1-x) NiO ₂ , V ₂ O. ₅ can also be mentioned. Here, x shows 0-1. Furthermore, a part of the transition metal element of LiMn ₂ O ₄ , LiNiO ₂ such as Li _1-x Mn _{2 + x} O ₄ , LiNi _1-x Co _x O _2, etc. is at least one or more other transition metal elements or Li You can also list what you have replaced with. The organic positive electrode active material is at least one of polyaniline, polypyrrole, and 2,5-dimercapto-1,3,4-thiazole. An example of the inorganic positive electrode active material is fluoride perovskite (MF ₃ : M is any one of Fe, V, Ti, Co, and Mn).
-Negative electrode A negative electrode is formed from the negative electrode active material which can occlude or discharge | release metal ion, or contains a negative electrode active material. The negative electrode can have a current collector. As a negative electrode collector, copper, nickel, etc. can be made into forms, such as a net | network, a punched metal, foam metal, plate shape, foil shape, for example. A battery casing can also be used as the negative electrode current collector.

  Negative electrode active materials include metallic lithium, lithium alloys, metal materials that can store and release lithium, and alloy materials that can store and release lithium (not only alloys consisting of metals but also alloys of metals and metalloids). The structure includes solid solution, eutectic (eutectic mixture), intermetallic compounds or compounds in which two or more of them coexist), and compounds capable of occluding and releasing lithium (carbon 1 type or 2 types or more of negative electrode materials selected from the group which consists of material etc.).

Metal elements and metalloid elements that can constitute metal materials and alloy materials include tin (Sn), lead (Pb), aluminum (Al), indium (In), silicon (Si), zinc (Zn), and antimony (Sb). ), Bismuth (Bi), cadmium (Cd), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), zirconium (Zr), yttrium (Y ) And hafnium (Hf). Examples of these alloy materials or compounds include those represented by the chemical formula Ma _f Mb _g Li _h or the chemical formula Ma _s Mc _t Md _u . In these chemical formulas, Ma represents at least one of a metal element and a metalloid element capable of forming an alloy with lithium, Mb represents at least one of a metal element and a metalloid element other than lithium and Ma, Mc represents at least one of non-metallic elements, and Md represents at least one of metallic elements and metalloid elements other than Ma. The values of f, g, h, s, t, and u are f> 0, g ≧ 0, h ≧ 0, s> 0, t> 0, and u ≧ 0, respectively.

  Among these, a simple substance, alloy or compound of Group 4B metal element or semimetal element in the short-period type periodic table is preferable, and silicon (Si) or tin (Sn), or an alloy or compound thereof is particularly preferable. These may be crystalline or amorphous.

Examples of the anode material capable of inserting and extracting lithium further include other metal compounds such as oxide, sulfide, or lithium nitride such as LiN ₃ . Examples of the oxide include MnO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , NiS, and MoS. In addition, examples of the oxide that has a relatively low potential and can occlude and release lithium include iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, and tin oxide. Examples of the sulfide include NiS and MoS.

  The negative electrode active material can be used as it is, or can be used together with other necessary components. As other necessary components, a binder or the like can be employed. The binder has an action of connecting between the constituent elements included in the negative electrode layer and between the constituent elements and the negative electrode current collector. As the binder, organic binders and inorganic binders can be used, and the binders exemplified in the column of the positive electrode can be mentioned. Desirably, PVDF, polyvinylidene chloride, PTFE, Mention may be made of compounds such as CMC.

  The non-aqueous electrolyte is a non-aqueous electrolyte capable of conducting the aforementioned metal ions. For example, what melt | dissolved the support salt containing the metal ion corresponding to the metal ion which occlusion thru | or discharge | releases by a positive / negative electrode with respect to a nonaqueous solvent can be illustrated. The non-aqueous electrolyte is interposed between the positive electrode and the negative electrode and becomes a medium for conducting metal ions between the two. As the supporting salt, a compound that does not generate and contain a Lewis acid (and / or compound group A), such as those having the above-described configuration (a), can be employed. The concentration of the supporting salt is preferably 0.1 to 2.0M, and more preferably 0.8 to 1.2M.

  As the non-aqueous solvent, an aprotic organic solvent can be used. Examples of such organic solvents include cyclic carbonates, chain carbonates, cyclic esters, cyclic ethers, chain ethers, and the like. Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate and the like. Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate, and ethyl methyl carbonate (EMC). Examples of the cyclic ester carbonate include gamma butyrolactone and gamma valerolactone. Examples of the cyclic ether include tetrahydrofuran and 2-methyltetrahydrofuran. Examples of the chain ether include dimethoxyethane and ethylene glycol dimethyl ether. These may be used alone or in combination. In addition, as the ionic conductor, an ionic liquid, a gel electrolyte, a solid electrolyte, or the like may be used.

  The battery according to the present embodiment can include a separator interposed between the positive electrode and the negative electrode, a battery case that stores the positive and negative electrodes, and the nonaqueous electrolyte. As the separator, a porous film or a non-woven fabric that can exist stably in the atmosphere in the battery can be used. For example, a separator can be comprised from polyolefin, polyester, etc. The battery case can also be formed from a material that is stable against the atmosphere in the battery. Further, as described above, it can also serve as a current collector for the positive electrode and / or the negative electrode, and can also serve as an electrode terminal for exchanging electric power with the outside.

The nonaqueous electrolyte battery of the present invention will be described in more detail based on the following examples. In the following tests, we evaluate the stability of radical materials when they are stored in several non-aqueous electrolytes, and consider the relationship between the type of electrolyte (especially the supporting salt) and the stability of the radical material. did.
(Test Example 1)
LiBOB as a supporting salt was added at a concentration of 0.1 mol / L to a mixed solvent as a non-aqueous solvent in which EC, DMC, and EMC were mixed at a volume ratio of 30:30:40. The nonaqueous electrolyte of Test Example 1 was obtained. To the non-aqueous solvent of Test Example 1, 4-hydroxy-TEMPO as a radical material was added so as to have a concentration of 0.01 M to obtain a test solution of Test Example 1.

The test solution of Test Example 1 was allowed to stand at room temperature and 60 ° C. for 12 days in an inert atmosphere, and then a platinum electrode as a working electrode and metallic lithium as a counter electrode and a reference electrode at a scanning speed of 100 mV / s. Cyclic voltammograms were measured by cyclic voltammetry. The results are shown by the solid line (left at room temperature) and the broken line (left at 60 ° C.) in FIG.
(Test Examples 2 and 3)
In place of the supporting salt (LiBOB) in Test Example 1, a test solution having the same configuration was prepared except that LiPF ₆ was used in Test Example 2 and LiBF ₄ was used in Test Example 3 at the same concentration (0.1 mol / L). The same test as in Test Example 1 was performed. The results are shown in FIG. 2 (Test Example 2, solid line: left at room temperature, broken line: left at 60 ° C.) and FIG. 3 (Test Example 3, solid line: left at room temperature, broken line: left at 60 ° C.).
(Discussion)
As is clear from FIG. 1, in the test solution of Test Example 1, the adsorption / desorption of anions was observed both at room temperature and at 60 ° C., indicating that the radical compound was acting. On the other hand, as is clear from FIGS. 2 and 3, the test solutions of Test Examples 2 and 3 containing LiPF ₆ and LiBF ₄ which are support salts that generate Lewis acid in the present mixed solvent were allowed to stand at room temperature. In Fig. 5, anion transfer was observed, but it was revealed that the progress of anion transfer was less when left at 60 ° C (it was hardly observed in Test Example 2 and was greatly impaired in Test Example 3). Here, the test solution contains a Lewis acid that can contact the radical material (within the nonaqueous electrolyte).

  Therefore, it has been clarified that the radical material is deactivated to some extent by including the Lewis acid in a form that can contact the radical material. That is, the Lewis acid is not included so as to come into contact with the radical material (it is estimated that the Lewis acid may be generated in the middle), that is, when the radical material is applied to the battery. It was found that the decrease in battery performance can be suppressed.

Assuming this mechanism, the one shown in FIG. 4 can be exemplified. That is, in LiPF ₆ and LiBF ₄ , the dissociated anion changes to a Lewis acid when left at 60 ° C., causing a strong interaction between the radical of the radical material and the Lewis acid, decomposition of the radical itself, or decomposition of the electrolyte solvent. Therefore, it is presumed that the anion transfer will not proceed because the Lewis acid interferes with the anion transfer. On the other hand, the anion produced by dissociation of LiBOB does not change to Lewis acid even when left at 60 ° C., and does not cause a strong bond with the radical of the radical material. Sometimes, it can be assumed that the transfer of the anion can proceed without interruption. As described above, since the Lewis acid acts on the radical of the radical material and inhibits the exchange of anions, it is desirable that the Lewis acid is not contained and is not generated.

Claims (5)

A positive electrode with a radical material;
A negative electrode capable of inserting or extracting metal ions (M ions; M is selected from the group consisting of Li, Na, K, Ca, Mg, Zn, Fe, and Al);
A non-aqueous electrolyte interposed between the positive electrode and the negative electrode ;
A secondary battery having
The non-aqueous electrolyte is Me _a X _b (Me is selected from the group consisting of Li, Na, K, Ca, and Al; X is a bis (oxalate) borate anion, malonato- Oxalatoborate (malonato-oxalatoborate) anion and bis (malonato) borate anion are selected from the group; a and b are determined from 1 to 3 depending on the oxidation number of Me that integer) the supporting salt viewed free consisting and non-aqueous electrolyte battery characterized by containing no Lewis acid to contact the radical material. The non-aqueous electrolyte battery according to claim 1, wherein the Lewis acid is the following compound group A.
Compound Group A includes AsF ₅ , AgF, AgBF ₄ , BH ₃ , B ₂ H ₆ , CaCl ₂ , (Cp) ₂ Os, (Cp) ₂ Ru, CuCl ₂ , Cu (BF ₄ ) ₂ , GaCl ₃ , GaF ₃ , Ga ₂ H ₆ , GeF ₄ , GeH ₄ , H ₂ SO ₄ , HCOOH, HCN, HF, HCl, HBr, HI, Mg (CH ₂ SCH ₃ ) ₂ , MnCl ₂ , MoF ₆ , NaBF ₄ , NaB ( C ₆ H ₅ ) ₄ , NbCl ₅ , NH ₄ [B (C ₆ H ₅ ) ₃ CH ₃ ], NH ₄ PF ₆ , NO ₂ (SbF ₆ ), NO (SbCl ₆ ), NO ₂ (BF ₄ ), _{PF 3, PF 5, Pd (} CN) 2, PtCl 4, PtI 4, SbCl 3, SbF 6, SiCl 4, SiF 4, SF 4, SnH 4, SO 3, TiCl 3, WF 6 _{ZrCl 4, BX 3, AlX 3} , SnX 2, SnX 4, MgX 2, TiX 4, PdX 2, CrX 3, FeX 3, CoX 3, NiX 2, SbX 5, InX 3, ZnX 2 (X is F ^-, Cl ⁻ , Br ⁻ , I ⁻ , CF ₃ SO ₃ ⁻ , C ₆ F ₅ ⁻ , C ₆ H ₅ ⁻ , OCH ₂ CH ₃ ^— ), Ho (CF ₃ SO ₃ ) ₂ , Ca (CF ₃ SO ₃ ) ₂ , Sc (CF ₃ SO ₃ ) ₃ , Y (CF ₃ SO ₃ ) ₃ , Ln (CF ₃ SO ₃ ) ₃ (Ln is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu), BF ₃ - diethyl etherate complex, BF ₃ - acetic acid complex, BF ₃ - methyl -t- butyl ether complex, BF ₃ - di -n- butyl etherate Complex, F ₃ - dimethyl etherate complex, BF ₃ - dimethyl sulfide complex, BF ₃ - phenol complex, BF ₃ - phosphate complex, BF ₃ - tetrahydrofuran complex, triflic acid, tributyl borane, tributyl borate, and tris (perfluorophenyl) A group of boranes. The nonaqueous electrolyte battery according to claim 1 , wherein the radical material is a nitroxyl radical compound. The non-aqueous electrolyte is ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyl lactone, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, 1,2-dimethoxyethane, methyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran 1,3- dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, 3-methyl-oxazolidinone, methyl formate sulfolane, dimethyl sulfoxide, and one or claims, including two or more non-aqueous solvent is selected from the group consisting of acetonitrile The nonaqueous electrolyte battery according to any one of 1 to 3 . The non-aqueous solution according to any one of claims 1 to 4 , wherein the positive electrode has an oxygen permeable film whose one side is in contact with an oxygen-containing gas, and the radical material is disposed on the other side of the oxygen permeable film. Electrolyte battery.

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