Abstract: A difluorophosphate effective as an additive for a nonaqueous electrolyte for secondary battery is produced by a simple method from inexpensive common materials. The difluorophosphate is produced by reacting lithium hexafluorophosphate with a carbonate in a nonaqueous solvent. The liquid reaction mixture resulting from this reaction is supplied for providing the difluorophosphate in a nonaqueous electrolyte comprising a nonaqueous solvent which contains at least a hexafluorophosphate as an electrolyte lithium salt and further contains a difluorophosphate. Also provided is a nonaqueous-electrolyte secondary battery employing this nonaqueous electrolyte.

Abstract: Electrolyte compositions suitable for use in batteries, such as a lithium ion battery, are disclosed The electrolyte compositions include functionalized metal oxide particles In several embodiments the compositions utilize the presence of solvent or a scavenger Methods of making and using electrolyte compositions are also disclosed Articles of manufacture containing an electrolyte composition are also disclosed

Abstract: Disclosed is a lithium-ion secondary battery which includes a carbonaceous material in an anodic active material mix, and a cyclic carbonate and a chain carbonate both in an electrolytic solution. The solvent contains an additive which is a substance having a LUMO energy determined through molecular orbital calculation of lower than the LUMO energy of ethylene carbonate determined through molecular orbital calculation and having a HOMO energy lower than the HOMO energy of vinylene carbonate determined through molecular orbital calculation, the electrolytic solution contains LiPF6 or LiBF4 as an electrolyte, and the electrolytic solution shows a reduction-reaction current of ?0.05 mA/cm2 (provided that a reaction current on the reducing side be negative) or less at a potential lower than 1 V and shows an oxidation-reaction current of 0.5 mA/cm2 (provided that a reaction current on the oxidizing side be positive) or more at a potential higher than 5.

Abstract: Described is an electrode comprising and preferably consisting of electronically active material (EAM) in nanoparticulate form and a matrix, said matrix consisting of a pyrolization product with therein incorporated graphene flakes and optionally an ionic lithium source. Also described are methods for producing a particle based, especially a fiber based, electrode material comprising a matrix formed from pyrolized material incorporating graphene flakes and rechargeable batteries comprising such electrodes.

Abstract: A non-aqueous electrolytic solution is advantageously used in preparation of a lithium secondary battery excellent in cycle characteristics. In the non-aqueous electrolytic solution for a lithium secondary battery, an electrolyte salt is dissolved in a non-aqueous solvent. The non-aqueous electrolytic solution further contains a vinylene carbonate compound in an amount of 0.01 to 10 wt. %, and an alkyne compound in an amount of 0.01 to 10 wt. %.

Abstract: There is provided an electrochemical device provided with an electrolytic solution comprising (I) a solvent for dissolving an electrolyte salt comprising (A) a fluorine-containing ether represented by the formula (1): Rf1—O—Rf2 wherein Rf1 and Rf2 are the same or different and each is a fluorine-containing alkyl group having 3 to 6 carbon atoms, (B) a cyclic carbonate, and (C) a chain carbonate being compatible with both of the fluorine-containing ether (A) and the cyclic carbonate (B), and (II) an electrolyte salt, in which the solvent (I) for dissolving an electrolyte salt comprises 30 to 60% by volume of the fluorine-containing ether (A), 3 to 40% by volume of the cyclic carbonate (B) and 10 to 67% by volume of the chain carbonate (C) based on the whole solvent (I), and when the electrochemical device is provided with such an electrolytic solution, no phase separation occurs even at low temperature, flame retardancy and heat resistance are excellent, solubility of an electrolyte salt is high, discharge

Abstract: An additive for an electrolyte of a lithium secondary battery, the additive including a polysiloxane-based compound represented by Formula 1 below: In formula 1 R1, R2, R3, A1, A2, l, m, n, o and p are as described in the detailed description of the present invention.

Abstract: Provided is a lithium secondary battery comprising an anode, a cathode and a non-aqueous electrolyte, wherein the anode includes an aqueous binder, and the non-aqueous electrolyte contains (a) a cyclic anhydride or a derivative thereof; and (b) any one anion receptor selected from the group consisting of a borane compound, a borate compound and mixtures thereof. According to the present invention, a stable SEI film is formed on the anode, and the life characteristics of the battery are improved by controlling the LiF content in the SEI film.

Abstract: Disclosed is a non-aqueous electrolyte solution for a lithium secondary battery. The non-aqueous electrolyte solution includes an electrolyte salt and an organic solvent. The non-aqueous electrolyte solution further includes (a) a polyfunctional compound including two or more functional groups, at least one of which is an acryl group, and (b) an anion receptor selected from the group consisting of a borane compound, a borate compound and a mixture thereof. Further disclosed is a lithium secondary battery including the non-aqueous electrolyte solution. A stable solid electrolyte interface (SEI) film is formed on an anode of the lithium secondary battery. The amount of LiF in the SEI film is controlled, achieving improved cycle life characteristics of the battery.

Abstract: A battery is disclosed. The battery includes an electrolyte activating one or more anodes and one or more cathodes. The electrolyte includes one or more salts dissolved in a solvent. The solvent includes one or more first siloxanes and/or one or more first silanes. Each of the first siloxanes and/or first silanes have one or more first substituents that each include a poly(alkylene oxide) moiety. The solvent also includes one or more second siloxanes and/or one or more second silanes. Each of the second siloxanes and/or second silanes have one or more second substituents that each include a carbonate moiety.

Abstract: A galvanic cell having a lithium metal or an alloy comprising a lithium metal as anode material, having an electrolyte comprising lithium bis(oxalate)borate and at least one other lithium complex salt in an aprotic solvent or solvent mixture, in the ratio of lithium complex salt in the conducting salt equals 0.01 to 20 mol %.

Abstract: A battery capable of improving cycle characteristics is provided. A separator arranged between a cathode and an anode is impregnated with an electrolytic solution. The electrolytic solution includes: a solvent; and an electrolytic salt, in which the solvent includes a compound having a difluoroalkene structure. The content of the compound having a difluoroalkene structure in the solvent is within a range from 1 wt % to 5 wt % both inclusive.

Abstract: An organic electrolyte solution includes a lithium salt; an organic solvent including a high permittivity solvent and a low boiling solvent; and a vinyl-based compound represented by Formula 1 below, wherein m and n are each independently integers of 1 to 10; X1, X2, and X3 each independently represent O, S, or NR9; and R1, R2, R3, R4, R5, R6, R7, R8, and R9 are represented in the detailed description. The organic electrolyte solution of the present invention and a lithium battery using the same suppress degradation of an electrolyte, providing improved cycle properties and life span thereof.

Abstract: An electrochemical energy storage device includes a negative electrode which contains a carbon material and has a negative electrode potential of 1.4 V or less relative to a lithium reference when being charged, and a non-aqueous electrolyte solution prepared by dissolving a lithium salt, an ammonium salt, and at least one kind of fluorinated benzene selected among hexafluorobenzene, pentafluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene and 1,2,3-trifluorobenzene, in a non-aqueous solvent.

Abstract: The present invention provides a simple method for producing a difluorophosphate from a source material, the difluorophosphate being useful as additives for nonaqueous electrolyte solutions for secondary batteries. In the method, a source material containing a carbonate and/or a borate is allowed to react with a source gas which contains P and F and which may further contain O as required. The source material may contain lithium carbonate. The source gas may be produced by decomposing LiPF6. The source gas may be produced in such a manner that LiPF6 and lithium carbonate are mixed and then subjected to reaction. The nonaqueous electrolyte solution contains the product obtained from the reaction.

Abstract: A process for producing a solvent mixture comprising (A) at least one compound of formula (I) (B) at least one compound of formula (II a) or (II b) (C) optionally at least one additive selected from aromatic compounds, sultones and exo-methylene ethylene carbonates, melamine, urea, organic phosphates and halogenated organic carbonates, (D) optionally at least one lithium salt, and from 3 to 30 weight ppm of water, which process comprises (a) components (A), (B) and, if used, (C) being mixed with one another, (b) dried over at least one ion exchanger or molecular sieve, (c) separated from ion exchanger or, respectively, molecular sieve, and (d) at least one lithium salt, if used, being added, where the variables are defined as follows: R1, R2 are each the same or different and selected from C1-C4-alkyl, R3 is selected from hydrogen and C1-C4-alkyl.

Abstract: Electrolytes of lithium ion batteries of the present disclosure comprise: a lithium salt, a non-aqueous solvent, and an additive. The additive further comprises a first and second compound. The first compound is a 4 X1, 5 R1 [1,3]dioxolan-2-one, wherein X1 is selected from the group consisting of: F, Cl, and Br and R1 is selected from the group consisting of hydrogen and linear alkyl compounds having between 1 and 3 carbon atoms. The second compound has a molecular formula of: F(CF2CF2)x—CH2CH2—(CH2CH2O)yH, wherein x is any integer ranging from 1 to 7, and y is any integer ranging from 1 to 15.

Abstract: A battery includes a positive electrode mix having a positive electrode active material, a water soluble binder including a poly(acrylonitrile-co-acrylamide) polymer and water, and a conductive additive. The battery also includes a negative electrode mix having a negative electrode active material, a water soluble binder including a poly(acrylonitrile-co-acrylamide) polymer and water, and a conductive additive or additives. The battery also includes an electrolyte.

Abstract: A nonaqueous electrolyte having maleimide additives and rechargeable cells employing the same are provided. The nonaqueous electrolyte having maleimide additives comprises an alkali metal electrolyte, a nonaqueous solvent, and maleimide additives. Specifically, the maleimide additives comprise maleimide monomer, bismaleimide monomer, bismaleimide oligomer, or mixtures thereof. The maleimide additives comprise functional groups, such as a maleimide double bond, phenyl group carboxyl, or imide, enhancing the charge-discharge efficiency, safety, thermal stability, chemical stability, flame-resistance, and lifespan of the secondary cells of the invention.

Abstract: A non-aqueous liquid electrolyte to be used for a non-aqueous liquid electrolyte secondary battery containing a anode electrode and a cathode electrode, capable of intercalating and deintercalating lithium ions, and the non-aqueous liquid electrolyte. In the non-aqueous liquid electrode, the anode electrode contains an anode electrode active material having at least one kind of atom selected from the group consisting of Si atom, Sn atom and Pb atom. The non-aqueous liquid electrolyte also contains a carbonate having at least either an unsaturated bond or a halogen atom, and also contains a compound represented by formula (I) as defined herein and a saturated cyclic carbonate compound as defined herein.

Abstract: A non-aqueous electrolyte solution for a lithium secondary battery comprises a lithium salt and an organic solvent. The non-aqueous electrolyte solution further comprises a specific siloxane compound and a sulfonate compound. This non-aqueous electrolyte solution solves the capacity degradation phenomenon, which appears in a lithium secondary battery using a non-aqueous electrolyte solution containing only a specific siloxane compound when the lithium secondary battery is used for a long time, so this non-aqueous electrolyte solution is especially useful for high-capacity batteries.

Abstract: Disclosed is a non-aqueous electrolyte solution for a lithium secondary battery. The non-aqueous electrolyte solution includes a lithium salt, an organic solvent and additives. The additives include: 1 to 10% by weight of a mixture of a particular halogenated cyclic carbonate and a compound containing a vinylene or vinyl group; and 0.1 to 9% by weight of a nitrile compound having a C2-C12 alkoxyalkyl group. A lithium secondary battery including the non-aqueous electrolyte solution is also disclosed. The lithium secondary battery is protected from catching fire when overcharged and is prevented from swelling during storage at high temperature.

Abstract: An organic electrolytic solution including a lithium salt; an organic solvent including a high dielectric solvent and a low boiling point solvent; and an additive compound containing an electron withdrawing group and hydrocarbon-based substituents. A lithium battery using the organic electrolytic solution can have improved cycle characteristics and cycle life through preventing decomposition of the electrolyte.

Abstract: Disclosed is a sodium-ion secondary battery having excellent charge and discharge efficiencies as well as excellent charge and discharge characteristics, wherein charging and discharging can be repeated without causing problems such as deterioration in battery performance. Specifically disclosed is a sodium ion secondary battery which is provided with a positive electrode, a negative electrode having a negative electrode active material, and a nonaqueous electrolyte solution containing a nonaqueous solvent. The nonaqueous solvent is substantially composed of a saturated cyclic carbonate (excluding the use of ethylene carbonate by itself), or a mixed solvent of a saturated cyclic carbonate and a chain carbonate, and a hard carbon is used as the negative electrode active material.

Abstract: Novel multifunctional sulfone/fluorinated ester compounds are described. These compounds may be useful as non-aqueous electrolyte solvents, specialty solvents, and starting materials and intermediates for synthesis of dyes, agricultural chemicals, and pharmaceuticals.

Abstract: The present invention provides a simple method for producing a difluorophosphate from a source material, the difluorophosphate being useful as additives for nonaqueous electrolyte solutions for secondary batteries. In the method, a source material containing a carbonate and/or a borate is allowed to react with a source gas which contains P and F and which may further contain O as required. The source material may contain lithium carbonate. The source gas may be produced by decomposing LiPF6. The source gas may be produced in such a manner that LiPF6 and lithium carbonate are mixed and then subjected to reaction. The nonaqueous electrolyte solution contains the product obtained from the reaction.

Abstract: A nonaqueous electrolyte and a lithium-ion secondary battery using the same, wherein a mixture of a cyclic carbonate, a chain carbonate, a first phosphoric acid ester wherein bonding between carbons is a single bond, and a second phosphoric acid ester wherein bonding between carbons contains a double bond is used as the nonaqueous electrolyte. It is desirable that the first phosphoric acid ester is a trimethyl phosphate. In addition, it is desirable that the second phosphoric acid ester is a dimethylisopropenyl phosphate.

Abstract: Provided are a nonaqueous electrolytic solution including an electrolyte salt dissolved in a nonaqueous solvent, which is characterized by containing a fluorine-containing phenol represented by the following general formula (I) in an amount of from 0.01 to 3% by mass of the nonaqueous electrolytic solution, and is excellent in storage property of a primary battery, cycle property upon use of a secondary battery at a high temperature, and suppressing effect on the generation of a gas during the charged battery storing of the secondary battery, and a lithium battery using the solution. (In the formula, X1 to X5 each independently represent a fluorine atom or a hydrogen atom, and 3 to 5 thereof represent fluorine atoms).

Abstract: A nonaqueous electrolyte secondary battery includes a positive electrode having a positive-electrode active material, a negative electrode having a negative-electrode active material, and a nonaqueous electrolytic solution having a nonaqueous solvent dissolving a solute. The negative-electrode active material includes powdered silicon and/or a silicon alloy, the nonaqueous electrolytic solution includes additives composed of at least one fluorinated lithium phosphate selected from the group consisting of lithium monofluorophosphate, lithium difluorophosphate, and lithium trifluorophosphate and a diisocyanate compound, and the nonaqueous solvent includes a chain carbonate compound.

Abstract: A nonaqueous electrolytic solution which may suppress the overcharge of a battery and a nonaqueous electrolyte secondary battery using the solution are provided. The overcharge of the battery is suppressed by undergoing the electrolytic polymerization in the solution when the battery is overcharged, and simultaneously more effectively suppressed by increasing the internal resistance of the battery. The nonaqueous electrolytic solution comprises a polymer which undergoes the electrolytic polymerization in the range of 4.3V or more to 5.5V or less at the lithium metal standard voltage, having a repeating unit represented by the formula (1), an electrolytic salt and a nonaqueous solvent. [where, A is a functional group which undergoes the electrolytic polymerization in the range of 4.3V or more to 5.

Abstract: Organic electrolytic solutions and lithium batteries using the organic electrolytic solutions are provided. One organic electrolytic solution includes a lithium salt, a mixed organic solvent consisting of a high-dielectric constant solvent and a low-boiling point solvent, and a compound represented by Formula 1 or 2 as an additive. The organic electrolytic solution and the lithium battery using the organic electrolytic solution may inhibit the reductive cleavage reaction of a polar solvent, thereby increasing capacity retention of the battery, and improving charge-discharge efficiency and battery lifetime.

Abstract: An electrolyte for a lithium ion secondary battery and a lithium ion secondary battery comprising the electrolyte. The electrolyte comprises a non-aqueous organic solvent, a lithium salt, and at least one aromatic phosphate compound. Exothermic reactions are inhibited in the battery upon overcharge or during high-temperature storage to prevent an increase in the temperature of the battery, resulting in an improvement in safety. In addition, the battery exhibits good swelling stability during high-temperature storage as well as improved cycle life characteristics. The electrolyte further comprises an ethylene carbonate-based compound. The presence of the ethylene carbonate-based compound leads to further improvements in the overcharge safety, high-temperature safety and cycle life characteristics of the battery.

Abstract: The sudden generation of heat being frequently caused in the case of the overcharge of a lithium secondary cell which have a positive electrode comprising a composite metal oxide of lithium and cobalt or a composite metal oxide of lithium and nickel, a negative electrode comprising metallic lithium, a lithium alloy or a material capable of occluding and releasing lithium, and a nonaqueous electrolyte solution comprising a nonaqueous solvent and an electrolyte dissolved therein can be efficiently prevented by the addition, to the nonaqueous electrolyte solution, of an organic compound which, when the lithium secondary cell is overcharged, decomposes into a decomposition product capable of dissolving out the cobalt or nickel contained in the positive electrode and depositing it ion the negative electrode (for example, a tert-alkylbenzene derivative).

Abstract: Organic electrolyte solutions and lithium batteries using the same are provided. The organic electrolyte solutions use a silane compound that prevents crack formation caused by volumetric changes in the anode active material during battery charging/discharging. This improves charge/discharge characteristics, thereby also improving stability, reliability, and charge/discharge efficiency of the battery.

Abstract: Novel fluorinated cyclic carbonate compounds are described. These compounds may be useful as non-aqueous electrolyte solvents, specialty solvents, and starting materials and intermediates for synthesis of dyes, agricultural chemicals, and pharmaceuticals.

Abstract: The present invention provides a battery that experiences a small degree of temporal change from the initial battery properties over the long term storage period of the battery. Specifically, the present invention provides a lithium secondary battery, in which a positive electrode capable of storing and releasing lithium and a negative electrode capable of storing and releasing lithium are formed via an electrolyte, wherein: the electrolyte comprises a cyclic solvent and a chain-type solvent and contains a compound having a boron-oxygen bond (B—O) and a carbon-carbon double bond (C?C).

Abstract: An organic electrolyte solution and a lithium battery using the same are provided. The organic electrolyte solution uses a monomer compound which can be electrografted, and which prevents crack formation caused by volumetric changes in the anode active material during battery charging/discharging. This improves charge/discharge characteristics, thereby improving the stability, reliability, and charge/discharge efficiency of the battery.

Abstract: In the nonaqueous electrolyte secondary battery, the positive electrode active material is composed of a mixture of a lithium-cobalt composite oxide containing at least both zirconium and magnesium, and a lithium-manganese-nickel composite oxide containing at least both manganese and nickel. The nonaqueous electrolyte includes fluoroethylene carbonate and dimethyl carbonate as a nonaqueous solvent and further includes an additive expressed by General Formula (1), which having a capability to form an SEI surface film, and a higher oxidation resistance than that of VC. Thus, the negative electrode active material is unlikely to react with the organic solvent. Therefore, decomposition of the organic solvent is suppressed. Thus the battery having a long cycling life even when it is charged at a positive electrode charging potential of 4.4 to 4.6 V based on lithium and having a high residual capacity after storage at high temperature in a charged state is provided.

Abstract: A rechargeable lithium battery includes a positive electrode including a positive active material and an activated carbon, a negative electrode including a negative active material, and a lithium salt and a non-aqueous organic solvent, wherein the non-aqueous organic solvent includes about 30 volume % to about 90 volume % of propylene carbonate.

Abstract: Disclosed is a lithium battery including: a positive electrode including manganese dioxide as a positive electrode active material; a negative electrode including at least one selected from lithium metal and a lithium alloy, as a negative electrode active material; a porous insulating member interposed between the positive electrode and the negative electrode; and an organic electrolyte. The organic electrolyte contains 0.0008 to 1.2% by weight of an alkyl ester of an aliphatic hydroxycarboxylic acid. The alkyl ester may be a C1-6 alkyl ester of an aliphatic hydroxycarboxylic acid having 2 to 7 carbon atoms, such as a C1-4 alkyl 4-hydroxybutyrate.

Abstract: A lithium ion battery capable of maintaining for a long time fire resistance of a nonaqueous electrolytic solution at a time of battery abnormality to secure safety is provided. In the lithium ion battery, two kinds of organic solvent, EC and DEC, are used for mixed organic solvent which forms the nonaqueous electrolytic solution, and liquid flame retardant formed by phosphazene A having a boiling point closely to that of EC and phosphazene B having a boiling point closely to that of DEC is added to the electrolytic solution. At battery abnormality, when the battery temperature goes up due to internal short circuit of positive and negative electrodes caused by melting of separators to decompose each of EC and DEC, the phosphazene A and B, each having the boiling point closely to that of EC and DEC, decompose timely to function, thereby fire resistance of the electrolytic solution can be maintained for a long time to secure safety of the battery at the time of battery abnormality.

Abstract: A solvent for a non-aqueous electrolytic solution providing a lithium secondary cell being specifically excellent in discharge capacity, rate characteristic and cycle characteristic and having improved incombustibility (safety), a non-aqueous electrolytic solution using the solvent, and further a lithium secondary cell are provided. The solvent for dissolving an electrolyte salt of a lithium secondary cell comprises at least one fluorine-containing solvent (I) selected from the group consisting of fluorine-containing ether, fluorine-containing ester and fluorine-containing chain carbonate, a fluorine-containing aromatic compound (II), in which a part or the whole of hydrogen atoms are replaced by fluorine atoms, and other carbonate (III), the non-aqueous electrolytic solution comprises the solvent and an electrolyte salt, and the lithium secondary cell uses the non-aqueous electrolytic solution.

Abstract: This invention provides a process for producing a lithium secondary battery. The process comprises: (a) providing a positive electrode; (b) providing a negative electrode comprising a carbonaceous material capable of absorbing and desorbing lithium ions, wherein the carbonaceous material is obtained by chemically or electrochemically treating a laminar graphite material to form a graphite crystal structure having an interplanar spacing d002 of at least 0.400 nm as determined from a (002) reflection peak in powder X-ray diffraction; and (c) providing a non-aqueous electrolyte disposed between the negative electrode and the positive electrode to form the battery structure. This larger interplanar spacing (greater than 0.400 nm, preferably no less than 0.55 nm) implies a larger interstitial space between two graphene planes to accommodate a greater amount of lithium. The resulting battery exhibits an exceptionally high specific capacity, an excellent reversible capacity, and a long cycle life.

Abstract: An electrochemical cell comprising a cathode comprising an electrode active material that reversibly intercalates and de-intercalates any of cations and molecules; an anode comprising an electrode active material that reversibly intercalates and de-intercalates any of cations, anions, and molecules; a separator material that separates the cathode from the anode; and an electrolyte comprising a base electrolyte composition, an ionic compound additive, and a solvent comprising any of aqueous and non-aqueous electrolyte solvents, wherein the additive dissolves in the base electrolyte composition as well a majority of the aqueous or non-aqueous electrolyte solvents, wherein the additive comprises a solubility of at least approximately 0.01 in the base electrolyte composition, wherein the additive dissociates into corresponding cations and anions upon dissolution, and wherein the cations originate from a metal element and reduce to an elemental form at a potential that is at least approximately 0.

Abstract: An organic electrolytic solution for a lithium primary or secondary battery includes a lithium salt; an organic solvent; a radical initiator represented by Formula 1 below; and a polymerizable monomer represented by Formula 2 below: R1—N2+X???<Formula 1> wherein R1, R2, R3, R4, and X? are described herein. The organic electrolytic solution improves charge-discharge efficiency and increases cell capacity of the lithium primary or secondary battery.

Abstract: An object of the present invention is to provide a lithium ion battery in which the deterioration during the high temperature storage is suppressed. The lithium ion battery is a lithium ion battery 100 having a cathode 3 capable of occluding and releasing lithium ions, an anode 6 capable of occluding and releasing lithium ions, a separator 7 disposed between the cathode 3 and the anode 6 and an organic electrolyte solution, wherein the organic electrolyte solution contains a plurality of solvents, an additive and an electrolyte, the electrolyte contains lithium hexafluorophosphate (LiPF6), and the additive contains vinylene carbonate or a derivative thereof and a compound represented by the following formula (I): wherein R1, R2 and R3 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 3 carbon atoms.

Abstract: The present invention provides a lithium secondary battery having excellent battery characteristics such as battery cycling property, electrical capacity and storage property. The present invention relates to a nonaqueous electrolytic solution for lithium secondary batteries in which an electrolyte salt is dissolved in a nonaqueous solvent, the nonaqueous electrolytic solution comprising a formic ester compound having a specific structure in an amount of 0.01 to 10% by weight of the nonaqueous electrolytic solution, and a lithium secondary battery using the same.

Abstract: The sudden generation of heat being frequently caused in the case of the overcharge of a lithium secondary cell which have a positive electrode comprising a composite metal oxide of lithium and cobalt or a composite metal oxide of lithium and nickel, a negative electrode comprising metallic lithium, a lithium alloy or a material capable of occluding and releasing lithium, and a nonaqueous electrolyte solution comprising a nonaqueous solvent and an electrolyte dissolved therein can be efficiently prevented by the addition, to the nonaqueous electrolyte solution, of an organic compound which, when the lithium secondary cell is overcharged, decomposes into a decomposition product capable of dissolving out the cobalt or nickel contained in the positive electrode and depositing it ion the negative electrode (for example, a tert-alkylbenzene derivative).

Abstract: The present invention provides a simple method for producing a difluorophosphate from a source material, the difluorophosphate being useful as additives for nonaqueous electrolyte solutions for secondary batteries. In the method, a source material containing a carbonate and/or a borate is allowed to react with a source gas which contains P and F and which may further contain O as required. The source material may contain lithium carbonate. The source gas may be produced by decomposing LiPF6. The source gas may be produced in such a manner that LiPF6 and lithium carbonate are mixed and then subjected to reaction. The nonaqueous electrolyte solution contains the product obtained from the reaction.

Abstract: A non-aqueous electrolyte comprising (i) a non-aqueous solvent, especially mainly composed of a cyclic carbonate and a cyclic ester and optionally a linear carbonate, and (ii) an electrolyte salt, especially LiBF4, dissolved therein and (iii) a vinyl sulfone derivative having the formula (I): wherein R indicates a C1 to C12 alkyl group, C2 to C12 alkenyl group, or C3 to C6 cycloalkyl, and also a lithium secondary battery using the same are disclosed.