JP5477657B2 - Nonaqueous electrolyte and its use - Google Patents

Description

  The present invention relates to a nonaqueous electrolyte useful as a component of a nonaqueous secondary battery.

Lithium ion secondary batteries and other non-aqueous secondary batteries are becoming increasingly important as power sources for vehicles or as power sources for personal computers and portable terminals. In particular, a lithium ion secondary battery that is lightweight and obtains a high energy density is expected to be preferably used as a high-output power source mounted on a vehicle. As a non-aqueous electrolyte for a lithium ion secondary battery, a solution obtained by dissolving a lithium salt (supporting salt) such as LiPF _{6 in} a carbonate-based solvent such as ethylene carbonate, propylene carbonate, or diethyl carbonate is widely used. Patent Documents 1 to 3 are listed as technical documents related to the non-aqueous electrolyte.

JP 2008-262900 A JP 2007-027105 A JP 2008-137799 A

  In general, a secondary battery is required to have a property with little performance deterioration with respect to repeated charge and discharge. It has been pointed out that as a factor of performance deterioration in a lithium ion secondary battery, when charging / discharging, the electrolytic solution is decomposed on the electrode. As a technique for suppressing the decomposition of the electrolytic solution, a technique of adding an additive to the electrolytic solution is known. Such an additive is considered to decompose to form a film on the electrode surface, and the film suppresses further decomposition of the electrolytic solution. For example, the non-aqueous electrolyte described in Patent Document 1 contains oxocarbonic acid or a derivative thereof as an additive capable of exhibiting such action.

  The present invention relates to a nonaqueous electrolyte containing a predetermined additive, which can suppress deterioration (particularly capacity reduction) of the battery to a higher degree when used as an electrolyte of a nonaqueous secondary battery. One purpose is to provide Another related object is to provide a non-aqueous secondary battery (typically a lithium ion secondary battery) comprising such a non-aqueous electrolyte.

  The nonaqueous electrolyte disclosed herein contains a nonaqueous solvent and an amide lithium salt as an additive. The amide lithium salt is a derivative of a divalent or higher oxocarbonic acid (for example, squaric acid) or a divalent or higher carboxylic acid (for example, oxalic acid), and has at least one N-fluorinated alkanesulfonyl group. When used as an electrolyte of a non-aqueous secondary battery (for example, a lithium ion secondary battery), the non-aqueous electrolyte having such a composition can suppress deterioration due to charging / discharging of the battery (particularly, reduction in capacity) to a higher degree. Can be a water electrolyte.

  In the present specification, the “secondary battery” refers to a general power storage device that can be repeatedly charged and discharged, and is a term including a so-called storage battery such as a lithium secondary battery and a power storage element such as an electric double layer capacitor. The “non-aqueous secondary battery” refers to a battery provided with a non-aqueous electrolyte (typically, an electrolyte containing a supporting salt (supporting electrolyte) in a non-aqueous solvent). The “lithium secondary battery” refers to a secondary battery that uses lithium ions as electrolyte ions and is charged and discharged by the movement of lithium ions between the positive and negative electrodes. A secondary battery generally referred to as a lithium ion battery is a typical example included in the lithium secondary battery in this specification.

  In a preferred embodiment of the technology disclosed herein, 50% by volume or more of the non-aqueous solvent is composed of one or more carbonate solvents. In such an embodiment, the effect of containing the additive can be better exhibited.

  In another preferred embodiment, the N-alkanesulfonyl fluoride group of the amide lithium salt has 1 to 10 carbon atoms. For example, an N-perfluoroalkanesulfonyl group having 1 to 10 carbon atoms is preferable. An amide lithium salt having such a structure can be more soluble in a non-aqueous solvent than an amide lithium salt having too many carbon atoms than the above range. Therefore, it is easy to prepare a non-aqueous electrolyte containing the additive, and the amount (content) of the additive used can be selected from a wider range.

The nonaqueous electrolyte disclosed herein can be preferably implemented in an embodiment further containing a lithium salt (for example, LiPF ₆ ) as a supporting salt. A nonaqueous electrolyte having such a composition can be suitably used as a nonaqueous electrolyte for a lithium ion secondary battery, for example.

  Since the non-aqueous electrolyte according to the present invention contains the above-mentioned additive, it can be used as an electrolyte for non-aqueous secondary batteries to construct a battery with little deterioration due to charging / discharging (particularly capacity reduction). Therefore, this invention provides a non-aqueous secondary battery (for example, lithium ion secondary battery) provided with one of the non-aqueous electrolytes disclosed here as another aspect.

  Such a non-aqueous secondary battery includes, for example, a step of preparing (for example, manufacturing or purchasing) any of the non-aqueous electrolytes disclosed herein, and housing the non-aqueous electrolyte, the positive electrode, and the negative electrode in a battery container. And a process for constructing a non-aqueous secondary battery.

It is a perspective view which shows the external shape of the non-aqueous secondary battery which concerns on one Embodiment. It is the II-II sectional view taken on the line of FIG. It is a side view showing vehicles provided with a non-aqueous secondary battery concerning one embodiment. It is a fragmentary sectional view which shows the coin-type battery produced in the Example.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  The non-aqueous electrolyte disclosed herein (typically, an electrolyte that exhibits a liquid state at room temperature (for example, 25 ° C.), that is, an electrolytic solution) is characterized by including a predetermined amide lithium salt as an additive. In one preferred embodiment, the amide lithium salt is a derivative of a divalent or higher valent (for example, divalent to pentavalent, typically divalent) oxocarbonic acid (hereinafter, this type of amidelithium salt is referred to as “oxocarbon”). Also referred to as an acid-centered amidolithium salt). Another preferred embodiment is a derivative of a divalent or higher carboxylic acid (hereinafter, this type of amide lithium salt is also referred to as “amide lithium salt centered on carboxylic acid”).

The amidolithium salt in the technology disclosed herein has at least one, typically two or more (preferably two) N-alkanesulfonyl fluoride groups in one molecule. The N-alkanesulfonyl group is a group in which an alkanesulfonyl group is bonded to the nitrogen atom of the amide group, and can be represented by the general formula: N—SO ₂ R _f ; Here, R _f represents an alkyl group in which at least one hydrogen atom (H) is replaced by a fluorine atom (F). In one preferred embodiment, R _f is an alkyl group in which all hydrogen atoms are replaced with fluorine atoms (ie, a perfluoroalkyl group). The amide lithium salt having such a structure can be advantageous in terms of solubility in a non-aqueous solvent, electrochemical stability, and the like. The alkyl group may be linear or branched. From the viewpoint of cost and availability, an amide lithium salt in which the alkyl group is linear is more preferable. The number of carbon atoms of the alkyl group in the N-alkanesulfonyl fluoride group may be 1 to 16, for example. In view of ease of synthesis of the amide lithium salt, solubility in a non-aqueous solvent, etc., the N-fluorinated alkanesulfonyl group usually has 1 to 10 carbon atoms (typically 1 to 8, for example, 1 The additive which is ~ 6) is preferred.

  The amidolithium salt centered on oxocarbonic acid will be described in more detail. Here, oxocarbonic acid is a general term for cyclic compounds in which enediol (—C (OH) ═C (OH) —) is connected by a carbonyl group. In the present specification, the divalent oxocarbonic acid refers to an oxocarbonic acid having 2 hydroxyl groups. Examples of the divalent or higher oxocarbonic acid include squaric acid (tetragonal acid), croconic acid (pentagonal acid), rhodizonic acid (hexagonal acid), and heptagonic acid (pentagonic acid). Of these, squaric acid is particularly preferable.

  An amide lithium salt centered on an oxocarbonic acid (for example, squaric acid) includes, for example, an amide of oxocarbonic acid (for example, squalamide) corresponding to the chemical structure of the target compound and a halide (for example, fluoride) of fluorinated alkanesulfonic acid. ) In the presence of a suitable base to synthesize an amide having an N-alkanefluoride sulfonyl group and centering on an oxocarbonic acid (for example, squaric acid), and then converting the amide to lithium hydroxide, It can be synthesized by reacting with a basic lithium compound such as lithium carbonate or butyl lithium. As the base, triethylamine, pyridine and the like can be used. As the reaction solvent, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazo An aprotic polar solvent such as lysinone can be preferably employed. In order to obtain a good yield, the above reaction is preferably carried out in a closed container such as a sealed tube.

  Next, the amide lithium salt centered on carboxylic acid will be described in more detail. The carboxylic acid is a compound having two or more valences, that is, two or more (typically two) carboxyl groups. Amide lithium salts centered on dicarboxylic acids having 2 to 6 carbon atoms are preferred. Specific examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid. An amidolithium salt centered on oxalic acid having the smallest molecular weight among dicarboxylic acids is particularly preferred from the viewpoint that the addition effect can be exhibited with respect to the amount used (content based on mass).

  Amidolithium salts centered on carboxylic acids, for example, react with carboxylic acid halides (for example, chlorides) corresponding to the chemical structure of the target compound and alkali metal salts (for example, sodium salts) of fluorinated alkanesulfonylamides. To synthesize an amide having an N-fluorinated alkanesulfonyl group and centering on a carboxylic acid (for example, oxalic acid), and then the amide and a basic lithium compound such as lithium hydroxide, lithium carbonate, and butyl lithium. It can be synthesized by reacting. As the base, triethylamine, pyridine and the like can be used. As the reaction solvent, an aprotic polar solvent such as DMSO, THF, N, N-dimethylformamide, N, N-dimethylacetamide, NMP, 1,3-dimethyl-2-imidazolidinone can be preferably used. .

  As the non-aqueous solvent in the non-aqueous electrolyte disclosed herein, various aprotic solvents that are generally known to be usable as solvents for non-aqueous electrolytes (for example, electrolytes for non-aqueous secondary batteries) are used. Can be used. For example, various aprotic solvents such as carbonates, esters, ethers, nitriles, sulfones, and lactones can be used alone or in appropriate combination of two or more. Specific examples include ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), 1,2-dimethoxyethane, 1,2-diethoxyethane. , Tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, acetonitrile, propionitrile, nitromethane, N, N-dimethylformamide, dimethyl sulfoxide, sulfolane, γ-butyrolactone, etc. . The non-aqueous solvent preferably exhibits a liquid state at room temperature (for example, 25 ° C.) as a whole (when a plurality of compounds are included, as a mixture thereof).

  As a suitable example of the non-aqueous solvent in the technology disclosed herein, a non-aqueous solvent containing one or more carbonates, and the total volume of these carbonates accounts for 50% by volume or more of the total volume of the non-aqueous solvent ( Carbonate-based solvents). For example, the total volume of carbonates is 60% by volume or more (more preferably 75% by volume or more, more preferably 90% by volume or more, and substantially 100% by volume) of the total volume of the nonaqueous solvent. ) Is preferred.

The nonaqueous electrolyte disclosed herein typically contains a supporting salt (supporting electrolyte) in addition to the nonaqueous solvent and the additive (amide lithium salt). Examples of the supporting electrolyte include LiPF ₆ , LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiClO _4, etc., one kind selected from various lithium salts known to be capable of functioning as a supporting electrolyte for lithium ion secondary batteries (excluding lithium salts corresponding to the above additives) Or 2 or more types can be used. Among these, LiPF ₆ can be preferably used. The concentration of the supporting electrolyte (supporting salt) is not particularly limited, and can be, for example, the same level as that of a conventional lithium ion secondary battery. Usually, it is appropriate that the concentration of the supporting electrolyte is about 0.1 mol / L to 5 mol / L (for example, about 0.8 mol / L to 1.5 mol / L).

  The non-aqueous electrolyte disclosed herein can improve the capacity retention rate of the additive as compared to an electrolyte having a composition not containing the additive (for example, the capacity measured by the method described in the examples described later). The maintenance ratio can be improved by 1% or more). In view of solubility in a non-aqueous solvent (for example, a carbonate-based solvent), the content of the additive with respect to an electrolyte constituent other than the additive is usually 5% by mass or less (that is, other than the additive). A nonaqueous electrolyte is preferable in which the content of the additive is 5 g or less with respect to 100 g of the electrolyte constituent component. In a preferred embodiment, the content of the additive is 0.05 to 5% by mass (typically 0.1 to 5% by mass, for example 0.5 to 3% by mass). If the content of the additive is too small, a sufficient additive effect tends to be hardly exhibited. If the content of the additive is too large, it may be difficult to prepare the non-aqueous electrolyte, or the additive may be easily deposited in the battery container depending on the time, use environment, or the like.

  The technology disclosed here is widely applied to various non-aqueous secondary batteries, and has an effect of suppressing decomposition of the non-aqueous electrolyte and suppressing deterioration of the battery (for example, improving the capacity maintenance rate). It can be realized. In carrying out the technology disclosed herein, it is not necessary to clarify the reason why such an effect is obtained, but the following may be considered, for example. That is, an additive for suppressing decomposition of an electrolyte of a non-aqueous secondary battery (for example, an electrolyte using a carbonate-based non-aqueous solvent) is usually an electrolyte component (non-aqueous solvent, supporting salt) during initial charging or the like. Etc.), and an SEI (Solid Electrolyte Interface) film made of the decomposition products covers the electrode surface, thereby suppressing further decomposition of the electrolyte component. Since the additive in the technique disclosed herein is a compound containing lithium (amide lithium salt) itself, the characteristics of the SEI film (lithium ion conductivity, etc.) are compared with the case where an additive not containing lithium is used. ) Can be improved. In addition, a part of the lithium in the battery container is taken into the SEI film and deactivated (that is, the lithium can no longer contribute to the battery capacity by being fixed in the SEI film). However, since the technique disclosed here uses an additive containing lithium, at least a part of the capacity decrease due to the deactivation can be compensated. This is considered to improve durability against charge / discharge (capacity maintenance).

  Note that the non-aqueous electrolyte in the technology disclosed herein may be a part of the non-aqueous electrolyte even when the battery is constructed (assembled) by the initial charge / discharge or subsequent charge / discharge. Everything can be broken down. In the battery in such a state, the fact that the additive is contained in the nonaqueous electrolytic solution used at the time of battery construction indicates that, for example, in the mass analysis of the electrolytic solution or electrode, a peak attributed to the fluorinated alkyl group is present. It can be confirmed by observation. In addition, as a method for grasping the amount of the additive contained in the nonaqueous electrolytic solution used at the time of battery construction from the battery after the initial charge / discharge (or after further charge / discharge), for example, an electrode Mass spectrometry, IR analysis, and the like.

  Hereinafter, the present invention will be described in more detail with reference to a case where the present invention is mainly applied to a lithium ion secondary battery. However, the present invention is not intended to be limited to such a battery. In addition, in the following drawings, the same code | symbol is attached | subjected to the member and site | part which show | plays the same effect | action, and the overlapping description may be abbreviate | omitted or simplified. In addition, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships.

  As shown in FIG. 1 and FIG. 2, for example, as shown in FIGS. 1 and 2, the lithium ion secondary battery including any of the non-aqueous electrolytes disclosed herein includes a non-aqueous electrolyte (typically a non-aqueous electrolyte). In addition to the electrolytic solution 90, the battery case 10 is accommodated in a flat box-shaped battery case 10 corresponding to the shape of the electrode body 20. The opening 12 of the case 10 is closed with a lid 14. The lid body 14 is provided with a positive terminal 38 and a negative terminal 48 for external connection so that a part of the terminals protrudes to the surface side of the lid body 14. The lithium ion secondary battery 100 having such a configuration is provided in the lid body 14 after the electrode body 20 is accommodated inside the opening portion 12 of the case 10 and the lid body 14 is attached to the opening portion 12 of the case 10, for example. It can be constructed by injecting an electrolytic solution 90 from a prepared electrolytic solution injection hole (not shown) and then closing the injection hole.

  The electrode body 20 includes a positive electrode sheet 30 in which a positive electrode active material layer 34 is formed on the surface of a long sheet-like positive electrode current collector 32, and a negative electrode active material layer 44 on the surface of a long sheet-like negative electrode current collector 42. Are wound together with two long sheet-like separators 50 and wound, and the obtained wound body is crushed from the side direction and ablated to form a flat shape. Yes.

  The positive electrode sheet 30 is formed such that the positive electrode active material layer 34 is not provided (or removed) at one end portion along the longitudinal direction, and the positive electrode current collector 32 is exposed. Similarly, the negative electrode sheet 40 to be wound is not provided with (or removed from) the negative electrode active material layer 44 at one end along the longitudinal direction so that the negative electrode current collector 42 is exposed. Is formed. Then, the positive electrode terminal 38 is joined to the exposed end portion of the positive electrode current collector 32, and the negative electrode terminal 48 is joined to the exposed end portion of the negative electrode current collector 42, respectively. The positive electrode sheet 30 or the negative electrode sheet 40 is electrically connected. The positive and negative terminals 38 and 48 and the positive and negative current collectors 32 and 42 can be joined by, for example, ultrasonic welding, resistance welding, or the like.

  The positive electrode active material layer 34 includes, for example, a paste or slurry-like composition in which a positive electrode active material is dispersed in an appropriate solvent together with a conductive material, a binder (binder), and the like as necessary. It can preferably be prepared by applying and drying the composition. As the positive electrode active material, a material capable of reversibly occluding and releasing lithium is used, and one of substances conventionally used in lithium ion secondary batteries (for example, an oxide having a layered structure or an oxide having a spinel structure) Two or more kinds can be used without any particular limitation. Preferable examples include lithium-containing composite oxides such as lithium nickel composite oxides, lithium cobalt composite oxides, and lithium manganese composite oxides.

  Here, the lithium nickel-based composite oxide is an oxide having lithium (Li) and nickel (Ni) as constituent metal elements, and at least one other metal element (that is, Li and Ni) in addition to Li and Ni. An oxide containing a transition metal element other than Ni and / or a typical metal element) as a constituent metal element at a rate equivalent to or less than Ni in terms of the number of atoms (typically less than Ni). It means to include. Examples of the metal element other than Li and Ni include, for example, Co, Al, Mn, Cr, Fe, V, Mg, Ti, Zr, Nb, Mo, W, Cu, Zn, Ga, In, Sn, La, and Ce. It may be one or more metal elements selected from the group consisting of: The same meaning is applied to the lithium cobalt complex oxide and the lithium manganese complex oxide. As a preferred positive electrode active material in the technology disclosed herein, a lithium transition metal containing at least Ni, Co, and Mn as constituent metal elements (for example, containing substantially the same amount of Ni, Co, and Mn in terms of the number of atoms). Complex oxides are exemplified.

Other suitable examples of the material that can be used as the positive electrode active material include olivine type lithium phosphate and other polyanion materials. The lithium olivine is, for example, an olivine-type lithium phosphate (LiFePO ₄ , LiMnPO _4, etc.) represented by a general formula LiMPO ₄ (M is at least one element of Co, Ni, Mn, and Fe). obtain.

  Examples of the conductive material include carbon materials such as carbon powder and carbon fiber, and conductive metal powder such as nickel powder. As the carbon powder, carbon black such as acetylene black and furnace black can be preferably used. Such conductive materials can be used singly or in appropriate combination of two or more. Examples of the binder include carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), styrene butadiene block copolymer (SBR), and polyvinylidene fluoride (PVDF). Such a binder can be used individually by 1 type or in combination of 2 or more types as appropriate.

  The proportion of the positive electrode active material in the entire positive electrode active material layer is suitably about 50% by mass or more (typically 50 to 95% by mass), and usually about 70 to 95% by mass. preferable. When the conductive agent is used, the ratio of the conductive material in the entire positive electrode active material layer can be, for example, about 2 to 20% by mass, and preferably about 2 to 15% by mass. When using a binder, the ratio of the binder to the whole positive electrode active material layer can be, for example, about 1 to 10% by mass, and usually about 2 to 5% by mass is appropriate.

  For the positive electrode current collector 32, a conductive member made of a metal having good conductivity is preferably used. For example, aluminum or an alloy containing aluminum as a main component can be used. The shape of the positive electrode current collector 32 may vary depending on the shape of the lithium ion secondary battery, and is not particularly limited, and may be various forms such as a rod shape, a plate shape, a sheet shape, a foil shape, and a mesh shape. . In the present embodiment, a sheet-like aluminum positive electrode current collector 32 is used, and can be preferably used for the lithium ion secondary battery 100 including the wound electrode body 20. In such an embodiment, for example, an aluminum sheet (aluminum foil) having a thickness of about 10 μm to 30 μm can be preferably used.

  For example, the negative electrode active material layer 44 applies a paste or slurry composition in which a negative electrode active material is dispersed in an appropriate solvent together with a binder (binder) or the like to the negative electrode current collector 42, and the composition is applied to the negative electrode current collector 42. It can be preferably prepared by drying.

  As the negative electrode active material, one type or two or more types of materials conventionally used in lithium ion secondary batteries can be used without any particular limitation. For example, a carbon particle is mentioned as a suitable negative electrode active material. A particulate carbon material (carbon particles) containing a graphite structure (layered structure) at least partially is preferably used. Any carbon material of a so-called graphitic material (graphite), non-graphitizable carbon material (hard carbon), easily graphitized carbon material (soft carbon), or a combination of these materials is preferably used. obtain. Among these, graphite particles such as natural graphite can be preferably used. The proportion of the negative electrode active material in the entire negative electrode active material layer is not particularly limited, but it is usually appropriately about 50% by mass or more, preferably about 90 to 99% by mass (for example, about 95 to 99% by mass). It is.

  As a binder, the thing similar to the positive electrode mentioned above can be used individually or in combination of 2 or more types. What is necessary is just to select the addition amount of a binder suitably according to the kind and quantity of a negative electrode active material, for example, can be about 1-5 mass% of the whole negative electrode active material layer.

  As the negative electrode current collector 42, a conductive member made of a metal having good conductivity is preferably used. For example, copper or an alloy containing copper as a main component can be used. Further, the shape of the negative electrode current collector 42 can be in various forms like the positive electrode current collector 32. In the present embodiment, a sheet-like copper negative electrode current collector 42 is used, and can be preferably used for the lithium ion secondary battery 100 including the wound electrode body 20. In such an embodiment, for example, a copper sheet (copper foil) having a thickness of about 5 μm to 30 μm can be preferably used.

  As the separator 50 interposed between the positive electrode sheet 30 and the negative electrode sheet 40, the same separator as a general separator in the field can be used without particular limitation. For example, a porous sheet made of a resin such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide, a nonwoven fabric, or the like can be used. Preferable examples include a single layer or multilayer structure porous sheet (microporous resin sheet) mainly composed of one or more kinds of polyolefin resins. For example, a PE sheet, a PP sheet, a sheet having a three-layer structure (PP / PE / PP structure) in which PP layers are laminated on both sides of the PE layer, and the like can be suitably used. The thickness of the separator is preferably set within a range of approximately 10 μm to 40 μm, for example.

  The non-aqueous secondary battery (typically, a lithium ion secondary battery) disclosed herein can be used as a secondary battery for various applications because it has little deterioration due to charge and discharge. For example, as shown in FIG. 3, any non-aqueous secondary battery 100 disclosed herein can be suitably used as a power source for a vehicle driving motor (electric motor) mounted on a vehicle 1 such as an automobile. it can. Although the kind of vehicle 1 is not specifically limited, Typically, they are a hybrid vehicle, an electric vehicle, a fuel cell vehicle, etc. Such non-aqueous secondary battery 100 may be used alone, or may be used in the form of an assembled battery that is connected in series and / or in parallel.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples.

文献（J. Am. Chem. Soc. 2007, 129, 10320）に記載の手順で化合物１を用意した。^１Ｈ−ＮＭＲデータは該文献に記載のものと一致した。この化合物１を用いて、文献（J. Org. Chem. 2007, 72, 1951）に従って化合物２（スクアラミド）を合成した。^１Ｈ−ＮＭＲデータは該文献に記載のものと一致した。 <Synthesis of Additive A-4 (Lithium N, N′-Bis (Nonafuryl) squalamide)>

Compound 1 was prepared by the procedure described in the literature (J. Am. Chem. Soc. 2007, 129, 10320). ¹ H-NMR data was consistent with that described in the literature. Using this compound 1, compound 2 (squalamide) was synthesized according to the literature (J. Org. Chem. 2007, 72, 1951). ¹ H-NMR data was consistent with that described in the literature.

具体的には、密閉されたチューブ内で、１．１２ｇ（１当量）の化合物２と、１０．１ｇ（１０当量）のトリエチルアミンとを、７０．０ｍｌのＤＭＳＯに溶解させた。この溶液に、６．０４ｍｇ（２当量）のノナフリルフルロライド（Ｃ_４Ｆ_９ＳＯ_２Ｆ）を一度に加えた。この反応混合物を９０℃で攪拌しつつ、薄層クロマトグラフィ（ＴＬＣ）および^１３Ｃ−ＮＭＲにより反応の進行をモニターした。化合物２が完全に化合物３に転換されたところで、該反応混合物を室温に冷却し、塩酸酸性の水に注いでジエチルエーテルで３回抽出した。有機層を集めて硫酸ナトリウムで乾燥させ、減圧濃縮した。シリカゲルカラム（溶離液：酢酸エチル）で精製して、目的とする化合物３（Ｎ，Ｎ’−ビス（ノナフリル）スクアラミド）を得た。収量は３．８３ｇ、収率は５６．６％であった。 Next, an N-nonafryl group was introduced into squalamide.

Specifically, 1.12 g (1 equivalent) of Compound 2 and 10.1 g (10 equivalents) of triethylamine were dissolved in 70.0 ml of DMSO in a sealed tube. To this solution was added 6.04 mg (2 eq) nonafuryl fluoride (C ₄ F ₉ SO ₂ F) in one portion. While the reaction mixture was stirred at 90 ° C., the progress of the reaction was monitored by thin layer chromatography (TLC) and ¹³ C-NMR. When Compound 2 was completely converted to Compound 3, the reaction mixture was cooled to room temperature, poured into hydrochloric acid acidic water and extracted three times with diethyl ether. The organic layer was collected, dried over sodium sulfate, and concentrated under reduced pressure. Purification by a silica gel column (eluent: ethyl acetate) gave the target compound 3 (N, N′-bis (nonafuryl) squalamide). The yield was 3.83 g, and the yield was 56.6%.

具体的には、ＣＨ_３ＣＮ／Ｈ_２Ｏの３：１混合液２０ｍｌ中に１．０８ｇ（１当量）の化合物３を含む溶液に、０．１５ｇ（２．２当量）のＬｉＯＨ・Ｈ_２Ｏを一度に加えた。この反応混合物を室温で１時間攪拌した後、減圧下で濃縮して、リチウム塩３−Ｌｉ_２（添加剤Ａ−４）を黄色の固体として得た。収量は１０．９ｇ、収率は９９％以上であった。
リチウム塩３−Ｌｉ_２のスペクトルデータは、化合物３とほぼ同じであった。 Next, Compound 3-Li ₂ which is a lithium salt of Compound 3 was synthesized.

Specifically, 0.15 g (2.2 equivalents) of LiOH.H ₂ was added to a solution containing 1.08 g (1 equivalent) of compound 3 in 20 ml of a 3: 1 mixture of CH ₃ CN / H ₂ O. O was added at once. The reaction mixture was stirred at room temperature for 1 hour and then concentrated under reduced pressure to give lithium salt 3-Li ₂ (Additive A-4) as a yellow solid. The yield was 10.9 g, and the yield was 99% or more.
The spectral data of the lithium salt 3-Li ₂ was almost the same as that of the compound 3.

文献（J. Org. Chem. 2007, 72, 1951）に従って化合物１（スクアラミド）を用意した。^１Ｈ−ＮＭＲデータは該文献に記載のものと一致した。 <Synthesis of Additive A-8 (Lithium N, N′-Bis (perfluorooctylsulfonyl) squalamide)>

Compound 1 (squalamide) was prepared according to the literature (J. Org. Chem. 2007, 72, 1951). ¹ H-NMR data was consistent with that described in the literature.

Then, 5.0 g (2.0 eq) in a solution of 0.56 g (1 eq) squalamide 1 and 5.06 g (10 eq) triethylamine in 3.0 ml DMSO in a sealed tube. ) Perfluorooctanesulfonyl fluoride. The reaction mixture was stirred at 80 ° C. for 12 hours. The reaction mixture was then cooled to room temperature, poured into water, acidified with 4N aqueous hydrochloric acid, extracted with diethyl ether, and dried over sodium sulfate. When the crude mixture was analyzed by ¹³ C-NMR, the target compound 3 was also contained, but the main product was the monosulfonylated product 2. The analysis results of Compound 2 and Compound 3 are as follows.

The crude mixture was placed in a sealed tube and 2.5 g (1 eq) perfluorooctanesulfonyl fluoride and 5.06 g (10 eq) triethylamine were added without adding solvent. The reaction mixture was stirred at 120 ° C. for 24 hours and ¹³ C-NMR was monitored. When the monosulfonylated squalamide was completely consumed, the reaction mixture was cooled to room temperature. The reaction was then acidified with 4N aqueous hydrochloric acid, extracted with diethyl ether, dried over sodium sulfate, concentrated and purified by column chromatography on silica (eluent: ethyl acetate / methanol (20: 1)). I got a thing. This solid was redissolved in acetone, acidified with 4N aqueous hydrochloric acid, extracted again with ether, dried over sodium sulfate, and concentrated. The product was a light brown solid. The analysis results of Compound 3 (N, N′-bis (perfluorooctylsulfonyl) squalamide) are shown below.

具体的には、アセトン／Ｈ_２Ｏの５：１混合物中に１．５６ｇ（１．００当量）の化合物３を含む溶液に、０．１３４ｇ（２．２０当量）のＬｉＯＨ・Ｈ_２Ｏを一度に加えた。この反応混合物を室温で１時間攪拌した後、減圧下で濃縮して、リチウム塩３−Ｌｉ_２（添加剤Ａ−８）を黄色の固体として得た。収量は１．５８ｇ、収率は９９％以上であった。
化合物３と化合物３−Ｌｉ_２との^１３Ｃ−ＮＭＲの差異は僅かであった。

Next, Compound 3-Li ₂ which is a lithium salt of Compound 3 was synthesized.

Specifically, 0.134 g (2.20 eq) of LiOH.H ₂ O was added to a solution containing 1.56 g (1.00 eq) of Compound 3 in a 5: 1 mixture of acetone / H ₂ O. Added at once. The reaction mixture was stirred at room temperature for 1 hour and then concentrated under reduced pressure to give lithium salt 3-Li ₂ (Additive A-8) as a yellow solid. The yield was 1.58 g, and the yield was 99% or more.
The difference in ¹³ C-NMR between compound 3 and compound 3-Li ₂ was slight.

<Synthesis of Additive A-1 (Lithium N, N′-Bis (perfluoromethylsulfonyl) squalamide)>
Lithium N, N′-bis (perfluoromethylsulfonyl) squalamide (addition) was performed in the same manner as the synthesis of additive A-4 except that CF ₃ SO ₂ F was used instead of C ₄ F ₉ SO ₂ F. Agent A-1) was obtained.

<Preparation of non-aqueous electrolyte>
A solution containing LiPF ₆ at a concentration of 1 mol / L in a mixed solvent of EC and DEC (volume ratio 3: 7) was used as a reference solution, and the additives A-1, A-4 and A- prepared above were used as the reference solution. By adding 8 and dissolving, an electrolyte solution sample having the composition shown in Table 1 was prepared. In addition, as the electrolyte solution sample 4, the said reference solution was used as it was (without adding an additive). In Table 1, the addition amount of each additive in the samples other than the electrolyte solution sample 4 indicates the content of the additive when the amount of the reference solution is 1. That is, an electrolyte solution sample with an addition amount of 1 wt% contains 1 g of additive with respect to 100 g of the reference solution. However, the additive A-1 was less soluble in the reference solution than the additives A-4 and A-8. Therefore, as the electrolyte sample 1, the additive A-1 was added to the reference solution at 25 ° C. A solution (supernatant) dissolved until saturation was used. The content of the additive A-1 in Sample 1 was less than 0.1% by mass.

<Production of lithium ion secondary battery>
Using each electrolyte solution sample, a lithium ion secondary battery for evaluation was produced as follows.
The positive electrode for this lithium ion secondary battery was produced as follows. That is, to 125 ml of N-methylpyrrolidone (NMP) solution containing 5 g of PVDF as a binder, 85 g of LiCoO ₂ powder (theoretical discharge capacity 275 mAh / g) as a positive electrode active material and 10 g of acetylene black as a conductive material. In addition, a paste-like composition was prepared by kneading until uniform. This composition was applied to one side of an aluminum foil (positive electrode current collector) having a thickness of 15 μm so that the coating amount was 6.5 mg / cm ² (based on solid content). The coated material was dried and pressed, and then cut into a predetermined size (circular shape with a diameter of 14 mm) to obtain a positive electrode.

The negative electrode for the lithium ion secondary battery was produced as follows. That is, 92.5 g of graphite as a negative electrode active material was added to 125 mL of NMP solution containing 7.5 g of PVDF (binder), and kneaded until uniform to prepare a paste-like composition. This composition was applied to one side of a 15 μm-thick copper foil (negative electrode current collector) so that the coating amount was 4.3 mg / cm ² (based on solid content). The coated material was dried and pressed, and then cut into a predetermined size (circular with a diameter of 16 mm) to obtain a negative electrode.
As the separator, a polypropylene (PP) porous film having a thickness of 25 μm cut into a predetermined size (a circle having a diameter of 19 mm) was used.

  Using these battery components, a coin type (2032 type) battery 200 having a schematic structure shown in FIG. 4 was produced. That is, the positive electrode 30 and the negative electrode 40 produced above were laminated together with the separator 50 impregnated with each electrolyte solution sample 90 and accommodated in the container 80 (negative electrode terminal), and then the electrolyte solution sample was further dropped. Next, the container 80 was sealed with the gasket 60 and the lid 70 (positive electrode terminal) to obtain a total of 10 types of batteries 200 corresponding to the respective electrolyte samples. In the following description, a group of electrolytic solution samples that differ only in the concentration of the additive, for example, three samples of electrolytic solution samples 2-1, 2-2, and 2-3 are collectively referred to as “electrolytic solution sample 2”. May be written. The same applies to the electrolyte sample 3.

<Capacity retention measurement>
For each battery obtained above, the operation of charging to 4.1 V at a rate of 1/10 C at a temperature of 25 ° C. and the operation of discharging to 3.0 V at the same rate were repeated three times alternately. .
Subsequently, after charging until the voltage became 4.1 V at a rate of 1 C, constant current and constant voltage (CC-CV) charging was performed in which charging was further performed at the same voltage until the total charging time was 2 hours. Subsequently, at the same temperature, the operation of discharging at a constant current to 3.0 V at 1 C and the operation of charging at a constant current to 4.1 V at 1 C were repeated 200 cycles (cycle test). The discharge capacity at the first cycle (initial discharge capacity) was taken as 100%, and the maintenance ratio of the discharge capacity at the 200th cycle (discharge capacity after cycle) was calculated. The obtained results are also shown in Table 1.

As shown in Table 1, among each lithium ion secondary battery using an electrolytic solution having a composition containing LiPF ₆ as a supporting salt in a carbonate-based solvent as a nonaqueous solvent, an electrolytic solution sample containing no additive In the example using 4 (reference solution), the capacity retention rate was 88%. In contrast, 0.1 to 5% by mass of additive A-1, A-4 or A-8 which is a derivative of squaric acid and is a diamide lithium salt having two N-perfluoroalkanesulfonyl groups ( More specifically, in the examples using the electrolytic solution samples 1 to 3 contained 0.5 to 2% by mass, the capacity retention rate is 2% or more in comparison with the example using the electrolytic solution sample 4 ( 2-4%). According to the electrolyte samples 2 and 3 containing the additive A-4 or the additive A-8 in which the number of carbon atoms of the N-perfluoroalkanesulfonyl group is 3 to 10 (more specifically, 3 to 8), A higher capacity retention rate was achieved as compared with the electrolytic solution sample 1 containing the additive A-1 having 1 carbon atom. This is considered because the additives A-2 and A-3 have higher solubility in the carbonate-based solvent used here (and thus the reference solution), and are suitable for containing a larger amount of the additive. It is done. Moreover, the example using the additive A-2 having 3 to 6 carbon atoms generally showed a higher capacity retention rate than the example using the additive A-8. This is considered to be related to the higher solubility of the additive A-2 than the additive A-3.

−７０℃において、液体アンモニア約１００ｍｌにパーフルオロブタン−１−スルホニルフルロライド（化合物１）５０ｇを約３０分かけて滴下し、ゆっくりと室温まで昇温して一晩攪拌した。水４０ｍｌおよび６規定塩酸４０ｍｌを滴下した後、イソプロピルエーテル（ＩＰＥ）で抽出し、水で洗浄した後、硫酸マグネシウムで乾燥させた。上澄みを濃縮し、濃縮残渣をシリカゲルカラムで生成して、パーフルオロブタン−１−スルホンアミド（化合物２）を得た。溶離液としては、ヘプタン／酢酸エチル＝２／１の混合溶媒を使用した。収量は４７．３ｇ、収率は９５．５％であった。 <Synthesis of Additive B-4 (Lithium N, N′-bis (perfluorobutylsulfonyl) oxaamide)>

At −70 ° C., 50 g of perfluorobutane-1-sulfonylfluoride (Compound 1) was added dropwise to about 100 ml of liquid ammonia over about 30 minutes, and the temperature was slowly raised to room temperature and stirred overnight. After 40 ml of water and 40 ml of 6N hydrochloric acid were added dropwise, the mixture was extracted with isopropyl ether (IPE), washed with water, and dried over magnesium sulfate. The supernatant was concentrated, and the concentrated residue was produced on a silica gel column to obtain perfluorobutane-1-sulfonamide (Compound 2). As an eluent, a mixed solvent of heptane / ethyl acetate = 2/1 was used. The yield was 47.3 g, and the yield was 95.5%.

アルゴン気流下で脱水メタノール１５７ｍｌに金属ナトリウム２．３ｇを加えて反応させ、上記で得られたパーフルオロブタン−１−スルホンアミド（化合物２）３１．４ｇのジエチルエーテル溶液を滴下した。続いて、加熱還流下で３時間攪拌した後、室温に冷却し、溶媒を減圧留去して、ナトリウムパーフルオロブチルスルホニルアミド（化合物３）を得た。収量は３３．４ｇ、収率は１００％であった。

Under an argon stream, 2.3 g of metallic sodium was added to 157 ml of dehydrated methanol for reaction, and a diethyl ether solution of 31.4 g of perfluorobutane-1-sulfonamide (Compound 2) obtained above was added dropwise. Subsequently, the mixture was stirred for 3 hours under reflux with heating, then cooled to room temperature, and the solvent was distilled off under reduced pressure to obtain sodium perfluorobutylsulfonylamide (Compound 3). The yield was 33.4 g, and the yield was 100%.

アルゴン気流下において、上記経路により得られたナトリウムパーフルオロブチルスルホニルアミド３７ｇに脱水テトラヒドロフラン１１５ｍｌを加え、溶解させた。続いて、氷冷下でシュウ酸ジクロライド５．８ｇを３０分かけて滴下した後、室温で１．５時間反応させた。溶媒を減圧留去し、ナトリウムＮ，Ｎ’−ビス（パーフルオロブチルスルホニル）オキサアミド（化合物４）４０．８ｇを得た。続いて、この化合物４にジエチルエーテルと水を加え、塩酸を滴下してｐＨを１〜２に調整した。分液し、水層をジエチルエーテルで抽出し、合わせた有機層を水で洗浄した後、硫酸マグネシウムで乾燥させ、上澄みを濃縮した。濃縮残渣をトルエンで洗浄した後、酢酸エチルとヘプタンの混合溶媒から再結晶し、Ｎ，Ｎ’−ビス（パーフルオロブチルスルホニル）オキサアミド（化合物５）を得た。所望の目的物が得られたことは、^１Ｈ−ＮＭＲ、^１３Ｃ−ＮＭＲおよび^１９Ｆ−ＮＭＲにより確認した。化合物５の収量は１１．０ｇ、収率は３６．７％であった。

Under an argon stream, 115 ml of dehydrated tetrahydrofuran was added to and dissolved in 37 g of sodium perfluorobutylsulfonylamide obtained by the above route. Subsequently, 5.8 g of oxalic acid dichloride was added dropwise over 30 minutes under ice-cooling, and then reacted at room temperature for 1.5 hours. The solvent was distilled off under reduced pressure to obtain 40.8 g of sodium N, N′-bis (perfluorobutylsulfonyl) oxaamide (Compound 4). Subsequently, diethyl ether and water were added to this compound 4, and hydrochloric acid was added dropwise to adjust the pH to 1-2. The layers were separated, the aqueous layer was extracted with diethyl ether, the combined organic layers were washed with water, dried over magnesium sulfate, and the supernatant was concentrated. The concentrated residue was washed with toluene and recrystallized from a mixed solvent of ethyl acetate and heptane to obtain N, N′-bis (perfluorobutylsulfonyl) oxaamide (Compound 5). It was confirmed by ¹ H-NMR, ¹³ C-NMR and ¹⁹ F-NMR that the desired product was obtained. The yield of Compound 5 was 11.0 g, and the yield was 36.7%.

上記で得られたＮ，Ｎ’−ビス（パーフルオロブチルスルホニル）オキサアミド（化合物５）５．０ｇにアセトニトリルと水を加えて溶解させ、０．６４ｇのＬｉＯＨ・Ｈ_２Ｏを加えて室温で１時間攪拌した。その後、溶媒を減圧留去し、濃縮残渣を１２０℃で減圧乾燥して、目的物たるリチウムＮ，Ｎ’−ビス（パーフルオロブチルスルホニル）オキサアミド（化合物６；添加剤Ｂ−４）を得た。収量は５．１、収率は１００％であった。この目的物のＬｉ含量を誘導結合プラズマ発光分析法（ＩＣＰ−ＡＳＥ）により定量分析したところ、１．９４質量％であり、理論値（２．０９質量％）と良く一致していた。

Acetonitrile and water are added and dissolved in 5.0 g of the N, N′-bis (perfluorobutylsulfonyl) oxaamide (Compound 5) obtained above, and 0.64 g of LiOH · H ₂ O is added thereto at room temperature for 1 Stir for hours. Thereafter, the solvent was distilled off under reduced pressure, and the concentrated residue was dried under reduced pressure at 120 ° C. to obtain lithium N, N′-bis (perfluorobutylsulfonyl) oxaamide (compound 6; additive B-4) as a target product. . The yield was 5.1 and the yield was 100%. When the Li content of this target product was quantitatively analyzed by inductively coupled plasma optical emission spectrometry (ICP-ASE), it was 1.94% by mass, which was in good agreement with the theoretical value (2.09% by mass).

<Preparation and evaluation of non-aqueous electrolyte>
0.1 g of additive B- per 100 g of the above reference solution (electrolyte sample 4, ie, a solution containing LiPF ₆ at a concentration of 1 mol / L in a mixed solvent of EC and DEC (volume ratio 3: 7)) 4 was added and dissolved to prepare an electrolytic solution sample 5 having the composition shown in Table 2. A coin-type battery was produced in the same manner as described above except that this electrolyte sample 5 was used, and the capacity retention rate was measured in the same manner. At this time, in order to eliminate the influence of the measurement error, a cycle test was simultaneously performed on two types of batteries each using the electrolyte samples 4 and 5, and the capacity retention rate was measured. The obtained results are shown in Table 2.

  As shown in Table 2, the capacity retention rate of the lithium ion secondary battery using the electrolyte sample 4 (reference solution) containing no additive was 82%, whereas it was a dicarboxylic acid derivative. According to electrolyte sample 5 containing 0.1 to 5% by mass (here 0.1% by mass) of additive B-4, which is a diamide lithium salt having two N-perfluoroalkanesulfonyl groups, lithium ion It was confirmed that the capacity retention rate of the secondary battery was improved by 3%.

  As mentioned above, although this invention was demonstrated in detail, the said embodiment and Example are only illustrations and what changed and changed the above-mentioned specific example is contained in the invention disclosed here.

Further, the matters disclosed by this specification further include the following.
<Reference example>
To 12.5 ml of NMP solution containing 0.75 g of PVDF, 0.09 g of additive B-4 was added and dissolved. Further, 9.25 g of graphite was added and mixed until uniform to obtain a paste or slurry composition. This composition was applied to one side of a copper foil (current collector) having a thickness of 15 μm so that the coating amount was 4.3 mg / cm ² (based on solid content). The coated material was dried and pressed, and then cut into a predetermined size (circular with a diameter of 16 mm). Thus, the negative electrode (negative electrode sample 6) containing 1 mass% additive B-4 with respect to the negative electrode active material was obtained.

  The negative electrode sample 6 and the positive electrode were incorporated into a coin-type container together with the reference solution (electrolyte sample 4) to produce a coin-type battery as described above, and the capacity retention rate was measured in the same manner. At this time, in order to eliminate the influence of the measurement error, two types of batteries, the above-described battery using the negative electrode sample 6 and the battery similarly manufactured using the above-described negative electrode (that is, the negative electrode not containing the additive B-4), are used. The batteries were subjected to a cycle test at the same time, and the capacity retention rate was measured. The obtained results are shown in Table 3.

  As shown in Table 3, even when the additive B-4 is included in the negative electrode active material, as compared with the case where the additive is included in the electrolytic solution, as compared with the battery not using the additive. It was confirmed that the capacity retention rate can be improved (in this case, 3% improvement).

  Accordingly, the matters disclosed by this specification include a non-aqueous secondary battery (for example, a lithium ion secondary battery) including a negative electrode having any of the amide lithium salts disclosed herein. Such a non-aqueous secondary battery includes, for example, a positive electrode, a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode active material layer mainly composed of a negative electrode active material, and the negative electrode active material layer has a bivalent or higher valence. It may be a derivative of an oxocarbonic acid or a divalent or higher carboxylic acid containing an amidolithium salt having at least one N-fluorinated alkanesulfonyl group. Content of the said amide lithium salt in a negative electrode active material layer can be about 0.1-10 mass% (for example, 0.5-5 mass%) with respect to a negative electrode active material. The aspect in which the additive is contained in the negative electrode active material layer has an advantage that the amount of the additive used is not easily restricted by the solubility in the non-aqueous solvent constituting the non-aqueous electrolyte. This is particularly significant when using an amidolithium salt with relatively low solubility (for example, additive B-4, A-1, etc.). Moreover, it is good also as a non-aqueous secondary battery of the structure which made the negative electrode active material layer and each non-aqueous electrolyte contain the same or different amide lithium salt.

  The matter disclosed in this specification also includes a step of preparing a current collector mainly composed of a conductive metal, and a negative electrode active material and the amide lithium salt (that is, a divalent or higher valence) on the current collector. And forming a negative electrode active material layer containing at least one amide lithium salt having at least one N-fluorinated alkanesulfonyl group). A method for producing a negative electrode for a water secondary battery is included. Furthermore, the non-aqueous secondary battery manufacturing method characterized by constructing a non-aqueous secondary battery using this negative electrode is included.

1 Vehicle 20 Winding electrode body 30 Positive electrode sheet (positive electrode)
34 Positive electrode active material layer 40 Negative electrode sheet (negative electrode)
42 Negative electrode current collector 44 Negative electrode active material layer 50 Separator 90 Electrolytic solution (nonaqueous electrolyte)
100,200 Non-aqueous secondary battery

Claims (7)

A non-aqueous solvent;
As an additive, an amide lithium salt having at least one N-fluoroalkanesulfonyl group, which is a derivative of a divalent or higher oxocarbonic acid or a divalent or higher carboxylic acid , wherein the amide lithium salt is a lithium An ion bonded to an amide-linked nitrogen) ,
Containing a non-aqueous electrolyte.   The non-aqueous electrolyte according to claim 1, wherein the oxocarbonic acid is squaric acid.   The non-aqueous electrolyte according to claim 1, wherein the carboxylic acid is oxalic acid.   The non-aqueous electrolyte according to any one of claims 1 to 3, wherein the N-alkanefluoride group is an N-perfluoroalkanesulfonyl group having 1 to 10 carbon atoms.   The nonaqueous electrolyte according to any one of claims 1 to 4, wherein 50% by volume or more of the nonaqueous solvent is composed of one or two or more carbonate solvents.   The nonaqueous electrolyte according to claim 1, further comprising a lithium salt as a supporting salt.   A nonaqueous secondary battery comprising the nonaqueous electrolyte according to any one of claims 1 to 6.

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