Abstract: Provided are an electrolyte for a high-voltage lithium secondary battery and a high-voltage lithium secondary battery containing the same, and more particularly, an electrolyte for a high-voltage lithium secondary battery which may not be oxidized and decomposed at the time of being kept at a high voltage and a high temperature to prevent swelling of a battery through suppression of gas generation, thereby having excellent high-temperature storage characteristics and excellent discharge characteristics at a low temperature while decreasing a thickness increase rate of the battery, and a high-voltage lithium secondary battery containing the same.

Abstract: An electrode material includes Fe-containing olivine-structured LixAyDzPO4 (wherein A represents one or more elements selected from the group consisting of Co, Mn, Ni, Cu, and Cr; D represents one or more elements selected from the group consisting of Mg, Ca, Sr, Ba, Ti, Zn, B, Al, Ga, In, Si, Ge, Sc, Y, and rare earth elements; 0<x?2; 0<y?1; and 0?z?1.5) particles that are coated with a carbon coating film, in which an abundance of Fe is 0.01 to 0.1 mol with respect to 1 mol of LixAyDzPO4, and an abundance ratio (Fe/(Fe+A+D)) of Fe on surfaces of the LixAyDzPO4 particles is 0.02 to 0.25.

Abstract: The nonaqueous electrolyte battery according to one embodiment includes a positive electrode and a negative electrode. The positive electrode contains a positive electrode active material containing manganese-containing composite oxide. The negative electrode contains a negative electrode active material selected from the group consisting of titanium oxide and titanium-containing composite oxide. A ratio p/n of a capacity p per unit area of the positive electrode to a capacity n per unit area of the negative electrode is in the range of 0.8 or more and 1 or less.

Abstract: Disclosed is a lithium secondary battery including: an electrode assembly including a cathode including a cathode mixture layer formed on a cathode current collector, an anode including an anode mixture layer formed on an anode current collector, and a separator disposed between the cathode and the anode; and an electrolyte, wherein the anode includes lithium titanium oxide (LTO) as an anode active material, and four planes of the cathode mixture layer have the same or greater length than four planes of the anode mixture layer and thus the cathode mixture layer has the same or greater area than the anode mixture layer.

Abstract: The present disclosure refers to a secondary battery which comprises a high-voltage cathode active material and a separator whose pores are not obstructed even though being used together with the high-voltage cathode active material, thereby preventing the obstruction of pores in the separator and the formation of a dendrite in the anode and eventually providing good battery life performance.

Abstract: The present invention provides non-aqueous electrolyte solution for a lithium secondary battery, comprising a pyrimidine-based compound, a non-fluorinated solvent and a fluorinated solvent; and a lithium secondary battery using the same.

Abstract: The present invention provides non-aqueous electrolyte solution for a lithium secondary battery, comprising fluoroethylene carbonate and a pyrimidine-based compound; and a lithium secondary battery using the same.

Abstract: Disclosed is a lithium secondary battery including an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode and an electrolyte, wherein the anode includes a lithium titanium oxide (LTO) as an anode active material, and the lithium secondary battery has a charge cut-off voltage of 3.3 to 4 V and, when the charge cut-off voltage is reached, the anode has a potential of 0.75 to 1.545 V within a range within which a potential of the cathode does not exceed 4.95 V.

Abstract: A non-aqueous electrolyte includes (i) an inhibitor against a reaction between an anode and a linear ester; (ii) a mixed organic solvent containing cyclic carbonate and the linear ester; and (iii) an electrolyte salt, wherein the inhibitor is any one compound or a mixture of at least two compounds selected from the group consisting of cyclic carbonate with a vinyl group, fluorinated ethylene carbonate, vinylene carbonate, cyclic acid anhydride, a compound having a cyclic S?O group and an acrylate-based compound. Also, an electrochemical device includes a cathode, an anode and the above non-aqueous electrolyte.

Abstract: Provided is a cathode mixture which can have both ion conductivity and electron conductivity and with which a solid battery having an excellent output characteristic can be obtained. The cathode mixture includes a plurality of cathode active material particles, a fibrous electroconductive material, a particulate electroconductive material, and a solid electrolyte, wherein setting the total number of the plurality of cathode active material particles as 100%, the number of the cathode active material particles in contact with the fibrous electroconductive material via the particulate electroconductive material is 40% or more.

Abstract: A battery, particularly a lithium-metal battery or a lithium-ion battery, having at least one galvanic cell surrounded by a cell housing. To increase the safety of the battery and to close up again a cell opened by a safety device or by a leakage, the inner chamber of the cell housing of the at least one cell includes a first chemical component, a chamber bordering on at least one section of the outer side of the housing including a second chemical component; a solid reaction product being developable by the chemical reaction of the first and second chemical components. The first component is containable in the electrolyte of the cell and the second component in a cooling and/or tempering arrangement. Also described is a cooling and/or tempering arrangement based on it, and an electrolyte, an electrolytic liquid, a safety system, a method and a mobile or stationary system.

Abstract: Disclosed are a nonaqueous electrolyte for a lithium secondary battery containing a hetero polycyclic compound and a lithium secondary battery using the same.

Abstract: An alkali-ion battery is provided with a transition metal cyanometallate (TMCM) sheet cathode and a non-alkaline metal anode. The fabrication method mixes TMCM powders, conductive additives, and a polytetrafluoroethylene binder with a solution containing water, forming a wet paste. The wet paste is formed into a free-standing sheet of cathode active material, which is laminated to a cathode current collector, forming a cathode electrode. The free-standing sheet of cathode active material has a thickness typically in the range of 100 microns to 2 millimeters. The cathode electrode is assembled with a non-alkaline metal anode electrode and an ion-permeable membrane interposed between the cathode electrode and anode electrode, forming an assembly. The assembly is dried at a temperature of greater than 100 degrees C. The dried assembly is then inserted into a container (case) and electrolyte is added. Thick anodes made from free-standing sheets of active material can be similarly formed.

Abstract: Provided is a non-aqueous electrolyte solution including a non-aqueous organic solvent, an imide-based lithium salt, and at least one additive selected from the group consisting of lithium difluoro bis(oxalato)phosphate (LiDFOP), (trimethylsilyl)propyl phosphate (TMSPa), 1,3-propene sultone (PRS), and ethylene sulfate (ESa), as an electrolyte solution additive. According to the electrolyte solution additive for a lithium secondary battery of the present invention, the electrolyte solution additive may improve output characteristics at high and low temperatures and may prevent a swelling phenomenon by suppressing the decomposition of PF6? on the surface of a cathode, which may occur during a high-temperature cycle of a lithium secondary battery including the electrolyte solution additive, and preventing an oxidation reaction of an electrolyte solution.

Abstract: Disclosed are a precursor of a positive active material for a rechargeable lithium battery and a preparation method thereof, and a positive active material and a rechargeable lithium battery including the same, and specifically a precursor for a rechargeable lithium battery is represented by the following Chemical Formula 1, wherein a manganese ion concentration deviation in the precursor is within 3 wt %. NixCoyMn1?x?y?zMz(OH)2??[Chemical Formula 1] (0<x<1, 0?y<1, 0.5?1?x?y?z, 0?z<1, and M is at least one kind of metal selected from the group consisting of Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, and Zr.

Abstract: An electrode active material has, as a main component, a mixture of an organic compound containing a rubeanic acid and cyanomethanesulfonylamide. The rubeanic acid is represented by the following general formula: In the formula, n indicates an integer between 1 and 20, and R1-R4 indicate hydrogen atoms, halogen atoms, or a prescribed substituent group such as a hydroxide group, a 1-3C alkyl group, an amino group, a phenyl group, a cyclohexyl group, or a sulfo group.

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: Disclosed is an electrolyte for lithium secondary batteries including a lithium salt and a non-aqueous solvent, in which a silane based material is included in an amount of 0.1 to 20 wt % based on the total weight of the electrolyte, and a lithium secondary battery including the same.

Abstract: Disclosed are a non-aqueous electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the non-aqueous electrolyte, and the non-aqueous electrolyte for a rechargeable lithium battery includes a lithium salt; a non-aqueous organic solvent; and trialkylsilyl borate as an additive, wherein the non-aqueous organic solvent may include a solvent having a low melting point of less than or equal to about ?50° C. and ionic conductivity of greater than or equal to about 6 mS/cm at 25° C.

Abstract: Various embodiments are directed to flexible battery structures comprising a flexible hinge region. For example, a flexible battery structure may comprise a plurality of battery layers. A first portion of the layers may be continuous across the hinge region and one or more cell regions. A second portion of the layers may be discontinuous at the hinge region.

Abstract: In a method for preparing a cathode material for an alkali-sulfur cell, e.g., a lithium-sulfur cell, at least one polyacrilonitrile-sulfur composite material and elemental sulfur are mixed, in order to increase the voltage, the capacitance and the energy density.

Abstract: A stack type battery includes a stack including: a plurality of cathode sheets; a plurality of anode sheets, which are alternately disposed with the cathode sheets; and a plurality of separators, where each of the separator is disposed between a corresponding cathode sheet of the cathode sheets and a corresponding anode sheet of the anode sheets, where the stack includes first to third protrusions, the first protrusion includes a portion of the cathode sheets which does not overlap the anode sheets and the separators, and the second protrusion includes a portion of the anode sheets which does not overlap the cathode sheets and the separators.

Abstract: The present disclosure relates to an anode active material comprising a composite of a core-shell structure, a lithium secondary battery comprising the same, and a method of manufacturing the anode active material. According to an aspect of the present disclosure, there is provided an anode active material of a core-shell structure comprising a core including alloyed (quasi)metal oxide-Li (MOx—Liy) and a shell including a carbon material coated on a surface of the core. According to another aspect of the present disclosure, there is provided a method of manufacturing the anode active material of the core-shell structure. According to an aspect of the present disclosure, an anode active material with high capacity, excellent cycle characteristics and volume expansion control capacity, and high initial efficiency is provided.

Abstract: The present invention is to provide a nonaqueous electrolytic solution prepared by dissolving an electrolyte salt in a nonaqueous solvent, wherein the nonaqueous solvent includes 0.01 to 40% by volume of an ester having two alkyl groups at the ?-position carbon of the carbonyl group and being represented by the following general formula (I), and an energy storage device. (in the above formula, R1 is an alkyl group, an alkenyl group or an alkynyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom, R2 and R3 are an alkyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom, and R2 and R3 may be linked to each other to form a ring. However, when R2 and R3 do not form a ring, R3 is an alkyl group in which at least one of the hydrogen atoms may be substituted with a halogen atom.).

Abstract: A lithium ion secondary battery 100A has negative electrode active material particles 710A which include graphite particles that are at least partially covered by an amorphous carbon film 750. The negative electrode, active material particles 710A have a TG weight-loss-on-heating onset temperature T1 which satisfies the condition 500° C.?T1?615° C. and a micro-Raman G-band half-width Gh which satisfies the condition 20?Gh?28. This configuration makes it possible to obtain a lithium ion secondary battery 100A in which the reaction resistance in a low-temperature environment can be kept low.

Abstract: According to one embodiment, there is provided an electrode material. The electrode material includes an active material which includes a titanium oxide compound having a monoclinic titanium dioxide crystal structure. The electrode material further includes a compound which exists on the surface of the active material and has a trialkylsilyl group represented by the formula (I). wherein R1, R2 and R3, which may be the same or different, respectively represent an alkyl group having 1 to 10 carbon atoms.

Abstract: A stainless steel member comprising a stainless steel base metal; an oxide film located on the surface of the stainless steel base metal; an electroconductive layer located on the surface of the oxide film and comprising a nonmetallic electroconductive material; and an electroconductive material which is located so as to penetrate the oxide film and which electrically contacts the stainless steel base metal and the electroconductive layer is provided as a stainless steel member for a separator of a solid polymer fuel cell having excellent properties such that a degradation in performance is low even after prolonged operation. A solid polymer fuel cell using the stainless steel member is also provided.

Abstract: A chargeable and dischargeable secondary battery for use in electronic devices, industrial machines, electric-powered vehicles, is provided, along with an anodic electrode and a copper foil for anode current collector. It is an anode for secondary battery that utilizes non-aqueous electrolyte, which comprises a silicon-type active material film formed on one side or both sides of a current collector made of copper foil or copper alloy foil, wherein 1 g/m2 to 14 g/m2 of silicon-type active material film is formed on said current collector, and the lightness Y value in a XYZ colorimetric system (CIE 1931 standard colorimetric system) for the surface of said anode, onto which said silicon-type active material film is formed, is 15 to 50, and the surface roughness (ten point average roughness) Rz specified by the Japanese Industrial Standards (JIS B0601-1994 ten point average roughness) is 1.0 ?m or more and 4.5 ?m or less.

Abstract: A composition for forming a solid electrolyte layer for use in the formation of a solid electrolyte layer of a lithium ion secondary battery contains first particles made of a lanthanum titanate and second particles made of a lithium titanate. It is preferable that the first particles have an average particle size of 50 nm or more and 300 nm or less. It is preferable that the second particles have an average particle size of 10 nm or more and 50 nm or less.

Abstract: Provided are an electrode additive coated with a coating material made of electrically conductive materials such as metal hydroxides, metal oxides or metal carbonates, and an electrode and a lithium secondary battery comprising the same. The electrode additive in accordance with the present invention can improve high temperature storage characteristics of the battery, without deterioration of performance thereof.

Abstract: The invention relates to a method for preparing a polyacrylonitrile-sulfur composite material, in which, polyacrylonitrile is converted to cyclized polyacrylonitrile, and the cyclized polyacrylonitrile is reacted with sulfur to form a polyacrylonitrile-sulfur composite material. By a separation of the preparation method into two partial reactions, the reaction conditions are advantageously able to be optimized for the respective reactions and a cathode material is able to be provided for alkali-sulfur cells with improved electrochemical properties. In addition, the invention relates to a polyacrylonitrile-sulfur composite material, a cathode material, an alkali-sulfur cell or an alkali-sulfur battery as well as to an energy store.

Abstract: A lithium secondary battery has an anode, a cathode, a separator between the anode and the cathode and a non-aqueous electrolyte. The non-aqueous electrolyte includes a lithium salt; and a non-linear carbonate-based mixed organic solvent in which (a) a cyclic carbonate compound, and (b) a propionate-based compound are mixed at a volume ratio (a:b) in the range from about 10:90 to about 70:30. The cathode has a capacity density in the range from about 3.5 to about 5.5 mAh/cm2 and a porosity in the range from about 18 to about 35%. This battery may be manufactured as a high-loading lithium secondary battery.

Abstract: A non-aqueous electrolyte solution containing a lithium salt, a non-aqueous solvent, a cyclic carbonate compound having an unsaturated bond and a compound of the following formula (Ic): CFnH(3-n)CH2X3??(Ic) where n represents an integer of 1-3 and X3 represents a group selected from the group consisting of formulas (Ic-1), (Ic-2) and (Ic-4): —O—R31??(Ic-1) —O—Y3—O—R32??(Ic-2) and wherein R31, R32 and R34 represent, independently of each other, an alkyl group having 1-20 carbon atoms that may be substituted by a halogen atom, and Y3 represents a divalent hydrocarbon group having 1-10 carbon atoms that may be substituted by a halogen atom.

Abstract: The present invention intends to provide silicon-containing particles that, when used as a negative electrode active material for a nonaqueous electrolyte secondary battery, can form a nonaqueous electrolyte secondary battery that is less in volume change during charge/discharge and has high initial efficiency and excellent cycle characteristics. The present invention provides silicon-containing particles that are used as a negative electrode active material for a nonaqueous electrolyte secondary battery and have a diffraction line with a peak at 2?=28.6° in X-ray diffractometry, a negative electrode material for a nonaqueous electrolyte secondary battery therewith, a nonaqueous electrolyte secondary battery, and a method of manufacturing the silicon-containing particles.

Abstract: To provide a technique for simply and easily producing a high-purity difluorophosphate and provide a production process of an electrolytic solution using the obtained difluorophosphate, an electrolytic solution and a secondary battery. A process for producing a difluorophosphate, comprising the following step (1) or (2): (1) reacting (A) at least one member selected from the group consisting of oxoacids, oxoacid anhydrides and oxyhalides of phosphorus with (B) a hexafluorophosphate in the presence of hydrogen fluoride, or (2) reacting at least one halide selected from the group consisting of alkali metal halides, alkaline earth metal halides, aluminum halides and onium halides with difluorophosphoric acid in the presence of a hexafluorophosphate. Also, a nonaqueous electrolytic solution containing the obtained difluorophosphate, and a nonaqueous electrolytic secondary battery containing the nonaqueous electrolytic solution.

Abstract: An electrolyte solution for a rechargeable lithium battery that includes a lithium salt; a non-aqueous organic solvent including ethyl acetate; and an additive including a sultone-based compound, wherein the sultone-based compound is included in an amount ranging from 0.1 to 5 wt % based on the total amount of the electrolyte solution is provided.

Abstract: The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

Abstract: Providing a noble negative-electrode active material including silicon, and a production process for the same. A negative-electrode active material for non-aqueous-system secondary battery including a silicon phase and a composite oxide phase (a CaSiO3 phase, for instance) is obtained by mixing a silicon oxide (SiO, for instance) with a silicon compound (CaSi2, for instance), which includes silicon and at least one member of elements being selected from the group consisting of Group 2 (or Group 2A) elements in the Periodic Table, to prepare a mixed raw material, and then reacting the mixed raw material. The composite oxide phase demonstrates the advantage of inhibiting electrolytic solutions from decomposing in a smaller amount than does the conventional SiO2 phase.

Abstract: According to one embodiment, a battery electrode includes an active material layer and a current collector is provided. The active material layer contains particles of a monoclinic ?-type titanium complex oxide and particles of a lithium titanate having a spinel structure. When a particle size frequency distribution of particles contained in the active material layer is measured by the laser diffraction and scattering method, a first peak P1 appears in a range of 0.3 ?m to 3 ?m and a second peak P2 appears in a range of 5 ?m to 20 ?m in the frequency distribution diagram. The ratio FP1/FP2 of the frequency FP1 of the first peak P1 to the frequency FP2 of the second peak P2 is 0.4 to 2.3.

Abstract: According to one embodiment, there is provided an electrode for a nonaqueous electrolyte battery. The electrode includes an active material layer. The active material layer includes a monoclinic ?-type titanium composite oxide. When the electrode is subjected to an X-ray diffraction measurement using a Cu-K? ray source, a ratio of a reflection intensity I(020) of a peak derived from a plane (020) of a crystal of the monoclinic ?-type titanium composite oxide to a reflection intensity I(001) of a peak derived from a plane (001) of the crystal of the monoclinic ?-type titanium composite oxide being in the range from 0.6 to 1.2.

Abstract: A non-aqueous electrolyte solution including a lithium salt, a non-aqueous solvent, a cyclic carbonate compound having an unsaturated bond and a compound of formula R21—S(O)2—F in which R2 is an alkyl group having from 1 to 12 carbon atoms that may be substituted by a fluorine atom or an alkenyl group having from 2 to 12 carbon atoms that may be substituted by a fluorine atom, and the alkyl group or alkenyl group may have an ether linkage within its chain.

Abstract: A lithium secondary battery has an anode, a cathode, a separator between the anode and the cathode and a non-aqueous electrolyte. The non-aqueous electrolyte includes a lithium salt; and a non-linear carbonate-based mixed organic solvent in which (a) a cyclic carbonate compound, and (b) a propionate-based compound are mixed at a volume ratio (a:b) in the range from about 10:90 to about 70:30. The cathode has a capacity density in the range from about 3.5 to about 5.5 mAh/cm2 and a porosity in the range from about 18 to about 35%. This battery may be manufactured as a high-loading lithium secondary battery.

Abstract: The present invention provides a non-aqueous electrolyte solution that can be used as an electrolyte solution of a non-aqueous secondary battery to improve the discharge rate performance of the battery. The non-aqueous electrolyte solution comprises a non-aqueous solvent and a BF3-cyclic ether complex. The BF3-cyclic ether complex content is greater than zero part by mass, but less than 1 part by mass relative to 100 parts by mass of the total amount of other electrolyte solution components. Preferable examples of the BF3-cyclic ether complex include BF3-tetrahydropyran complex and BF3-dioxane complex.

Abstract: A lithium-ion storage battery includes LiFePO4 as an active material for a positive electrode, an active material for a negative electrode having a lithium insertion/extraction potential equal to or greater than 0.5 V vs. Li+/Li, and a separating element placed between the positive and negative electrodes. The active material for the negative electrode is a lithiated titanium oxide, a derivative of a lithiated titanium oxide, a non lithiated titanium oxide, a derivative of a non lithiated titanium oxide or a mixture thereof. The separating element is formed from a non-woven fabric comprising cellulose fibers or glass fibers of nanometric and/or micrometric size.

Abstract: In accordance with one embodiment, an electrochemical cell includes a negative electrode including a form of lithium, a positive electrode spaced apart from the negative electrode and including an electron conducting matrix and a lithium insertion material wherein Li2O2 is formed as a discharge product, a separator positioned between the negative electrode and the positive electrode, an electrolyte including a salt, and a polymer coating on the lithium insertion material, the polymer coating permeable to lithium ions and impermeable to the electrolyte.

Abstract: An electrolyte for a lithium battery, the electrolyte including a compound represented by Formula 1; a nonaqueous organic solvent; and a lithium salt. wherein, in Formula 1, X, Ya, Z, R1, and R2 are as defined.

Abstract: A production process for composite oxide expressed by a compositional formula: LiMn1-xAxO2, where “A” is one or more kinds of metallic elements other than Mn; and 0?“x”<1, obtained by preparing a raw-material mixture by mixing a metallic-compound raw material and a molten-salt raw material with each other, the metallic-compound raw material at least including an Mn-containing nitrate that includes one or more kinds of metallic elements in which Mn is essential, the molten-salt raw material including lithium hydroxide and lithium nitrate, and exhibiting a proportion of the lithium nitrate with respect to the lithium hydroxide (Lithium Nitrate/Lithium Hydroxide) that falls in a range of from 1 or more to 3 or less by molar ratio; reacting the raw-material mixture at 500° C. or less by melting it; and recovering the composite oxide being generated from the raw-material mixture that has undergone the reaction.

Abstract: Disclosed is a non-aqueous electrolyte comprising: an acrylate compound; a sulfinyl group-containing compound; an organic solvent; and an electrolyte salt. Also, disclosed is an electrode comprising a coating layer formed partially or totally on a surface thereof, the coating layer comprising: (i) a reduced form of an acrylate compound; and (ii) a reduced form of a sulfinyl group-containing compound. Further, disclosed is an electrochemical device comprising a cathode, an anode and a non-aqueous electrolyte, wherein (i) the non-aqueous electrolyte is the aforementioned non-aqueous electrolyte; and/or (ii) the cathode and/or the anode is the aforementioned electrode.

Abstract: Provided is a nonaqueous electrolyte solution battery with dramatically improved battery characteristics. A nonaqueous electrolyte solution battery prepared by using a nonaqueous electrolyte solution comprising (I) an aromatic carboxylic acid ester compound represented by General Formula (1) below; and (II) specific compounds, is improved in charge-discharge characteristics at high current densities, durability performance during high-temperature storage and overcharge characteristics. (in General Formula (1), A1 is —R1 or —OR1, with R1 being an optionally substituted hydrocarbon group with 10 or fewer carbon atoms; A2 is an optionally substituted aryl group; each of j and k is independently 0 or an integer greater than 0, and at least one of j and k is an integer not less than 1; and when k?1, A1 is —OR1, while when k=0, A1 is —R1; and the case of j=1, k=0 is not allowed).

Abstract: [Problem] To provide: a method for stabilizing a solution that contains LiPF6 by increasing thermal stability of LiPF6 without changing the structure thereof; an electrolyte solution for nonaqueous secondary batteries, which has increased thermal stability; and a nonaqueous secondary battery which has increased thermal stability. [Solution] To have a solution containing LiPF6 contain a phosphoric acid ester amide represented by general formula (I) in such an amount that the molar ratio of the phosphoric acid ester amide relative to LiPF6 is 0.001-2.