Abstract: Disclosed is a secondary battery including an electrolyte and/or an electrode, the electrolyte including an electrolyte salt and an electrolyte solvent, i) a cyclic carbonate compound substituted with at least one halogen element; and ii) a compound containing a vinyl group in a molecule thereof, and the electrode including a solid electrolyte interface (SEI) layer partially or totally formed on the surface thereof by electrical reduction of the two compounds.

Abstract: A non-aqueous electrolyte secondary battery having a positive electrode and a negative electrode with an active material capable of absorbing and desorbing lithium, a separator interposed between the positive and negative electrodes, and a non-aqueous electrolyte. The negative electrode active material is covered by a coating having elasticity. The fully elastic coating expands and contracts following the volume change of the negative electrode active material; thus, the coating brings out its desired functions without being damaged or broken. Regardless of the degree of the volume change of the negative electrode active material, a lasting coating without damage is formed on the negative electrode active material, to improve performances of the non-aqueous electrolyte secondary battery.

Abstract: The invention relates to an ionic liquid electrolyte comprising at least one ionic liquid of formula C+A? wherein C+ represents a cation and A? represents an anion, and at least one conducting salt, characterized in that it further comprises at least one anionic surfactant. The invention also relates to an A electrotechnical system, electrochemical accumulator and battery, and in particular, a lithium accumulator such as a button battery cell.

Abstract: A fluoride ion battery includes a substantially lithium-free anode and cathode. At least one of the anode or cathode contains fluorine, and a substantially lithium-free liquid electrolyte is used for charge transport. The electrolyte is liquid at temperatures below about 200 degrees Celsius, and can be formed from an organic-soluble fluoride salt dissolved in selected classes of solvents.

Abstract: The present invention provides a non-aqueous electrolytic solution for a lithium secondary battery, wherein the lithium secondary battery includes, as a cathode active material, a composite oxide in which at least 35% by mole of a transition metal included in the composite oxide is manganese, and wherein the non-aqueous electrolytic solution includes an unsaturated sultone.

Abstract: Polymeric ionic gels of ionic liquids having melting points below about 100° C. that are formed by the reaction of a heterocyclic amine with about 2.8 and about 3.2 moles of anhydrous hydrogen fluoride per mole of amine nitrogen. Electrochemical devices having non-aqueous electrolytes containing the ionic liquids and polymeric ionic gels are also disclosed.

Abstract: An electrolyte includes (a) a eutectic mixture of an alkoxy alkyl group-containing amide compound and an ionizable lithium salt; and (b) a carbonate-based compound. The electrolyte has excellent thermal and chemical stability and exhibits a low lowest limit of electrochemical window. Also, the electrolyte shows low viscosity and high ion conductivity, so it may be usefully applied as an electrolyte of electrochemical devices using various anode materials.

Abstract: A nonaqueous secondary battery comprising: a positive electrode; a negative electrode; and a nonaqueous electrolyte solution, wherein the nonaqueous electrolyte solution contains at least a cyclic nitrogen-containing compound represented by the general formula (1): wherein X represents an optionally branched divalent group derived from a chain saturated hydrocarbon and having 1 to 5 carbon atoms, ?C?CH2, ?C?O, ?C?S?O, ?O or ?S; and A1 and A2 may be the same or different and each represent an optionally substituted methylene group, ?C?O or ?SO2.

Abstract: Halogenated organic compounds that are inexpensive and are readily available have been used to present the examples of the invention. These chemicals, when in contact with water experience a reaction that releases oxy-halogenated acid. These compounds are weak acids and release hydrogen ions according to their ionization constant keeping a constant level of oxy-halogenated ion. These ions are capable of reacting with catalytic cathodes and can be coupled with anode materials to fabricate galvanic cells. Exemplary embodiments of the present invention include cells with flat and cylindrical form factors having a variety of anodes.

Abstract: Disclosed is an electrolyte for batteries, comprising: (a) an electrolyte salt; (b) an organic solvent; (c) a first compound having an oxidation initiation voltage (vs. Li/Li+) higher than the operating voltage of a cathode; and (d) a second reversible compound having an oxidation initiation voltage higher than the operating voltage of the cathode, but lower than the oxidation initiation voltage of the first compound. Also disclosed is a lithium secondary battery comprising said electrolyte. In the lithium secondary battery, two compounds having different safety improvement actions at a voltage higher than the operating voltage of the cathode are used in combination as electrolyte components. Thus, the safety of the secondary battery in an overcharged state can be ensured, and at the same time, the deterioration of the battery can be prevented from occurring when it is repeatedly cycled, continuously charged and stored at high temperature for a long time.

Abstract: A method of producing HCl from H2 and Cl2 is provided. In some embodiments, the method comprises at least one photochemical chamber placed in fluid communication with at least one source of H2 and at least one source of Cl2. In some embodiments, the photochemical chamber effects the formation of HCl through the use of at least one source of ultraviolet radiation contained therein. In some embodiments, the HCl product may be captured and used as a gas. In some embodiments, the HCl product may be absorbed into water to form an aqueous HCl solution.

Abstract: The invention relates to reactive ionic liquids containing organic cations with groups or substituents which are susceptible to electrochemical reduction and anions obtained from fluoroalkyl phosphates, fluoroalkyl phosphinates, fluoroalkyl phosphonates, acetates, triflates, imides, methides, borates, phosphates and/or aluminates, for use in electrochemical cells, such as lithium ion batteries and double-layer capacitors.

Abstract: Provided are a nonaqueous electrolyte for a secondary cell, and a secondary cell, which are free from erosion of electrodes or generation of carbon dioxide gas and which have a long-term nonflammability, an excellent low-temperature characteristic and a practically sufficient conductivity. A nonaqueous electrolyte for a secondary cell, which comprises a lithium salt, a specific hydrofluoroether and a specific glyme type solvent. A secondary cell comprising such a nonaqueous electrolyte for a secondary cell, a negative electrode made of a material capable of storing or discharging lithium ions electrochemically, or metal lithium or a lithium alloy, and a positive electrode made of a material capable of storing or discharging lithium ions electrochemically.

Abstract: An electrolyte solution used for an electrochemical device including an electrolyte and at least one of fluoro-containing compounds represented by the general formula (1): where, R1, R2 each represent a hydrogen atom, a fluorine atom, or an alkyl group of 1 to 10 carbon atoms in which R1 and R2 may be identical or different with each other, or a cyclic structure may be formed by providing bonding between the carbon atoms contained in R1 and R2.

Abstract: A process is provided to produce non-aqueous electrolytic solution for use in batteries having low acid content and low water content. The invention involves removing acids and water from non-aqueous electrolytic solutions typically found in lithium or lithium-ion batteries by using nitrogen-containing compounds such as triazines. After treatment by a triazine such as melamine, the concentrations of acids and water in the electrolytic solutions are substantially decreased. The present invention provides a process to prepare extremely pure electrolytic solutions having low (<20 ppm) concentrations of both water and acids.

Abstract: A rechargeable battery with aluminium anode containing a non aqueous electrolyte consisting of an ether as solvent and a lithium salt of an imide It is welt known that the ionisation energy of aluminium to Al3+ is about 12 times as big as the ionisation energy of lithium to Li1+. The redox potential however does not reflect this big difference because of the high enthalpy consumed in the formation of aluminium hydroxide when it goes from the anode to the aqueous electrolyte. Also the use of aqueous electrolyte do not allow the aluminium batteries to be rechargeable, because of the very strong bond between the aluminium and the oxygen atom in the electrolyte. We propose now a rechargeable battery where the aluminium ion is connected to the nitrogen atom of an imide which improves the redox potential by reducing the enthalpy of formation of the aluminium-nitrogen bond in the salt contained in the electrolyte.

Abstract: The invention relates to an electrolyte formulation comprising a) an ionic liquid which is electrochemically stable over a range of at least 4.5 V, has a viscosity of less than 300 mPa·s at 20° C. and has a conductivity of at least 1 mS/cm at 20° C., and b) an aprotic, dipolar solvent in an amount of 20 to 60% by volume based on the electrolyte formulation, wherein the conductivity of the electrolyte formulation is greater at least by a factor of 2 than the conductivity of the ionic liquid.

Abstract: An electrolyte for a lithium ion rechargeable battery, including a lithium salt, a non-aqueous organic solvent, a dihalogenated ethylene carbonate, and a halogenated ethylene carbonate. The electrolyte may include about 0.01 to about 2 weight % of the dihalogenated ethylene carbonate, and the electrolyte may include about 0.1 to about 10 weight % of the halogenated ethylene carbonate.

Abstract: The present invention relates to additives for electrolytes of lithium ion secondary batteries that include one or more of the following: 1,3-propane sultone, succinic anhydride; ethenyl sulfonyl benzene, and halobenzene. It can also include biphenyl, cyclohexylbenzene; and vinylene carbonate. The weight of said 1,3-propane sultone is between 0.5 wt. % and 96.4 wt. %, said succinic anhydride is between 0.5 wt. % and 96.4 wt. %; said ethenyl sulfonyl benzene is between 0.5 wt. % and 95.2 wt. %; and said halobenzene is between 0.5 wt. % and 95.2 wt. % of the weight of the additive. Batteries with electrolytes containing said additives have improved over-charge characteristics and low temperature properties, and reduced gas generation during charging and discharging.

Abstract: An electrochemical cell includes a cathode capable of reversibly releasing and receiving an alkali metal; an anode capable of reversibly releasing and receiving the alkali metal; and a non-aqueous electrolyte including one or more dissolved lithium salts, one or more nitriles, sulfur dioxide, and one or more other polar aprotic solvents.

Abstract: A non-aqueous electrolyte for a lithium battery includes a non-aqueous organic solvent, the organic solvent including one or more of a carbonate-based solvent, an ester-based solvent, an ether-based solvent, and/or a ketone-based solvent, a lithium salt, and a hexafluoroacetylacetone in an amount of about 0.02 parts by weight to about 10 parts by weight, based on 100 parts by weight of the non-aqueous organic solvent.

Abstract: Disclosed is an electrolyte for a secondary battery, comprising an eutectic mixture consisting of: (a) am amide group-containing compound with at least one EDG introduced into the N-position thereof; and (b) an ionizable lithium salt. Also, provided are a secondary battery comprising such an electrolyte, and a method of adjusting an electrochemical stability window of an eutectic mixture consisting of an amide group-containing compound and a lithium salt by regulating electron donating properties of at least one substituent group introduced into the N-position of the amide group-containing compound.

Abstract: A nonaqueous electrolyte solution in which an electrolyte salt is dissolved in an organic solvent includes, includes at least one or more compounds selected from the silicon compounds represented by general formula (1), (2), or (3) below: (In the formulae, each of R1, R2, and R3 independently represents a C1-8 alkyl, C2-8 alkenyl, C2-8 alkynyl, or C6-8 aryl group; R4 represents a C1-8 alkylene, C2-8 alkenylene, C2-8 alkynylene, or C6-8 arylene group; and n represents 1 or 2. When n is 1, X represents a fluorine atom, trifluoromethyl group, C1-8 alkoxy group, C2-8 alkenyloxy group, C6-8 aryloxy group, or C2-8 acyloxy group, C1-8 sulfonyloxy group, isocyanato group, isothiocyanato group, or cyano group. When n is 2, X represents a C1-8 alkylene group, C1-8 alkylenedioxy group, C2-8 alkenylene group, C2-8 alkenylenedioxy group, C2-8 alkynylene group, C2-8 alkynylenedioxy group, C6-8 arylene group, C6-8 arylenedioxy group, C2-8 diacyloxy group, oxygen atom, or direct bond.

Abstract: Disclosed are nonaqueous electrolyte additives, which can improve the safety of a battery upon overcharge of the battery without reducing the performance of the battery, as well as a nonaqueous electrolyte comprising the additives, and a lithium secondary battery comprising the nonaqueous electrolyte. More particularly, disclosed are a nonaqueous electrolyte comprising both fluorobiphenyl and fluorotoluene as additives, and a lithium secondary battery comprising the nonaqueous electrolyte.

Abstract: The present invention relates to electrolytes comprising tetracyanoborate and an organic cation as components of electrolytes in electrochemical and/or optoelectronic devices, in particular solar cells. This ionic liquid has low viscosity and can be used as electrolyte in the absence of a solvent. Importantly, the ionic liquid remains stable in solar cells even after prolonged thermal stress at 80° C. for 1000 hours. Photovoltaic conversion efficiency remained stable and keeping more than 90% of the initial value.

Abstract: To provide a novel pentafluorophenyloxy compound, a method for producing same, a nonaqueous electrolyte solution capable of forming a lithium secondary battery having excellent battery characteristics such as electrical capacity, cycling property and storage property, and a lithium secondary battery. A pentafluorophenyloxy compound represented by the general formula (I) shown below, a method for producing same, a nonaqueous electrolyte solution containing same and a lithium secondary battery: wherein R1 represents a —COCO— group, a S?O group or a S(?O)2 group, R2 represents an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group or an aralkyl group with the proviso that at least one of the hydrogen atoms of R2 may be each substituted with a halogen atom and that R2 does not represent an aryl group when R1 represents a —COCO— group.

Abstract: The present invention provides a lithium secondary battery which is improved in cycle characteristics and storage stability at an elevated temperature as well as protection from overcharge. In the battery, generation of a gas is also inhibited to prevent the battery from expansion. A non-aqueous electrolytic solution for the lithium secondary battery has an electrolyte in a non-aqueous solvent. The non-aqueous solvent is composed of a cyclic carbonate compound, a linear carbonate compound and a cyclohexylbenzene compound having a benzene ring to which one or two halogen atoms are attached. A volume ratio of the cyclic carbonate compound and the linear carbonate compound in the non-aqueous solvent is in the range of 20:80 to 40:60, or the non-aqueous solvent further contains a small amount of a branched alkylbenzene compound.

Abstract: An electrolyte composition includes (a) a solvent composition including at least one hydrofluoroether compound, the hydrofluoroether compound including two terminal fluoroalkyl groups and an intervening substituted or unsubstituted oxymethylene group, each of the fluoroalkyl groups including only one hydrogen atom and, optionally, at least one catenated (that is, in-chain) heteroatom, with the proviso that, when the oxymethylene group is unsubstituted, at least one of the terminal fluoroalkyl groups is branched and/or includes at least one catenated heteroatom; and (b) at least one electrolyte salt.

Abstract: Disclosed herewith are an additive mixture for the electrolyte of lithium ion secondary batteries and electrolyte of lithium ion secondary batteries comprising the said additive mixture. The additive mixture comprises biphenyl based compound 0.5-95.4 wt %, cyclohexyl benzene based compound 0.1-93.8 wt %, vinylene carbonate 0.4-93.2 wt %, t-alkyl benzene based compound 0.5-96.5 wt %, and phenyl vinyl sulfone 0.5-95.8% based on total weight of the additive mixture.

Abstract: The invention relates to an improvement in a cell which is normally susceptible to damage from overcharging comprised of a negative electrode, a positive electrode, and an electrolyte comprised of an overcharge protection salt carried in a carrier or solvent. Representative overcharge protection salts are embraced by the formula: MaQ where M is an electrochemically stable cation selected from the group consisting of alkali metal, alkaline earth metal, tetraalkylammonium, or imidazolium groups, and Q is a borate or heteroborate cluster and a is the integer 1 or 2.

Abstract: A battery capable of improving cycle characteristics is provided. A spirally wound electrode body in which a cathode and an anode are wound with a separator in between is included. An electrolytic solution in which an electrolyte salt is dissolved in a solvent is impregnated in the separator. The electrolytic solution contains a cyclic ester carbonate derivative having halogen atom such as 4-fluoro-1,3-dioxolan-2-one and a light metal salt such as difluoro[oxolate-O,O?]lithium borate, tetrafluoro[oxolate-O,O?]lithium phosphate, and difluoro bis[oxolate-O,O?]lithium phosphate.

Abstract: Disclosed is a secondary battery including a cathode, an anode, a separator, and an electrolyte, wherein the electrolyte includes a ternary eutectic mixture prepared by adding (c) a carbonate-based compound to a eutectic mixture containing (a) an amide group-containing compound and (b) an ionizable lithium salt, and the carbonate-based compound is included in an amount of less than 50 parts by weight based on 100 parts by weight of the electrolyte. The use of the disclosed ternary eutectic mixture having flame resistance, chemical stability, high conductivity, and a broad electrochemical window, as the electrolyte material, improves both the thermal stability and quality of the battery.

Abstract: A non-aqueous electrolyte secondary battery having a positive electrode and a negative electrode with an active material capable of absorbing and desorbing lithium, a separator interposed between the positive and negative electrodes, and a non-aqueous electrolyte. The negative electrode active material is covered by a coating having elasticity. The fully elastic coating expands and contracts following the volume change of the negative electrode active material; thus, the coating brings out its desired functions without being damaged or broken. Regardless of the degree of the volume change of the negative electrode active material, a lasting coating without damage is formed on the negative electrode active material, to improve performances of the non-aqueous electrolyte secondary battery.

Abstract: A battery includes: a positive electrode; a negative electrode; a nonaqueous electrolyte; and a separator, wherein the nonaqueous electrolyte contains at least one sulfonic anhydride selected from the group consisting of compounds represented by the following chemical formulae (1) to (4) and an aromatic compound represented by the following chemical formula (5).

Abstract: An electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the same, the electrolyte including a lithium salt, a silylborate-based compound, an anhydride component, and a non-aqueous organic solvent.

Abstract: An energy storage device structure comprises a first electrode layer, an electrolyte layer and a second electrode layer. At least one of the electrode layers comprise a metallic base layer and a layer of carbon nanotubes grown on the base layer, the carbon nanotube layer being arranged to face the electrolyte layer. The structure has much larger width and length than thickness, so it is rolled up or folded and then hermetically sealed to form an energy storage unit. The layer of carbon nanotubes is grown on the metallic base layer by a chemical vapor deposition process at a temperature no higher than 550° C. The carbon nanotubes in the carbon nanotube layer are at least partially aligned in a direction that is perpendicular to the surface of the metallic base layer.

Abstract: The present invention provides a nonaqueous electrolytic solution exhibiting excellent battery characteristics such as electrical capacity, cycle property and storage property and capable of maintaining the battery characteristics for a long tire, and a lithium secondary battery using the nonaqueous electrolytic solution. A nonaqueous electrolytic solution for a lithium secondary battery, in which an electrolyte salt is dissolved in a nonaqueous solvent, containing 0.1 to 10% by weight of an ethylene carbonate derivative represented by the general formula (I) shown below, and 0.

Abstract: Provided is a battery electrolyte comprising an electrolyte salt, an electrolyte solvent and a compound producing chemical reaction products with the exception of water through a chemical reaction with an acid (H+), and a secondary battery comprising the same. The battery electrolyte according to the present invention can achieve improved high-temperature storage characteristics and the life characteristics of the battery, by using a compound decreasing a concentration of HX (X=F, Cl, Br or I) through a chemical reaction with HX (X=F, Cl, Br or I) which is present in the battery and therefore causes deterioration of the battery performance.

Abstract: Disclosed herein is an electrolyte for lithium secondary batteries comprising: a chelating agent, which forms complexes with transition metal ions in the battery, and at the same time does not react and coordinate with lithium ions; a non-aqueous solvent; and an electrolyte salt, as well as a lithium secondary battery comprising the electrolyte. The chelating agent, which is contained in the electrolyte for lithium secondary batteries, can suppress a side reaction in which transition metal ions are reduced and deposited as transition metals on the anode. Also, the chelating agent can suppress internal short-circuits in the battery and the resulting voltage drop of the battery and a reduction in the safety and performance of the battery, which can occur when transition metals are deposited on the anode.

Abstract: A non-aqueous electrolytic solution secondary battery includes a positive electrode containing, as a positive electrode active material, a compound represented by the following general formula, LixFe1-yMyPO4, wherein M is at least one member selected from the group consisting of Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca and Sr; 0.9<x<1.2; and 0?y<0.3; a negative electrode containing a lithium metal, a lithium alloy or a material capable of doping and dedoping lithium; and a non-aqueous electrolytic solution, the non-aqueous electrolytic solution containing a fluorinated ethylene carbonate FEC.

Abstract: A resistance-stabilizing additive to an electrolyte for a battery cell in an implantable medical device is presented. At least one resistance-stabilizing additive is selected from a group comprising an electron withdrawing group, an aromatic diacid salt, an inorganic salt, an aliphatic organic acid, an aromatic diacid, and an aromatic monoacid.

Abstract: A process is provided to produce non-aqueous electrolytic solution for use in batteries having low acid content and low water content. The invention involves removing acids and water from non-aqueous electrolytic solutions typically found in lithium or lithium-ion batteries by using nitrogen-containing compounds such as triazines. After treatment by a triazine such as melamine, the concentrations of acids and water in the electrolytic solutions are substantially decreased. The present invention provides a process to prepare extremely pure electrolytic solutions having low (<20 ppm) concentrations of both water and acids.

Abstract: Disclosed is an electrolyte of a lithium secondary battery comprising a lithium salt, an organic solvent, and at least one additive compound selected from the group consisting of compounds represented by the following formula (1) and derivatives thereof: where R1 is selected from the group consisting of hydrogen radicals, alkyls, aryls, cycloalkyls, alkenyls, alkynyls, ester radicals, and aliphatic carbonate radicals. The electrolyte improves both swelling inhibition properties at high temperature and capacity characteristics of a lithium secondary battery.

Abstract: A battery capable of obtaining a high energy density and obtaining superior cycle characteristics is provided. The thickness of a cathode active material layer is from 100 ?m to 130 ?m. The thickness of an anode active material layer is from 85 ?m to 120 ?m, and the volume density of the anode active material layer is from 1.7 g/cm3 to 1.85 g/cm3. An electrolytic solution contains 4-fluoro-1,3-dioxolane-2-one. Thereby, even when the thicknesses of the cathode active material layer and the anode active material layer are increased, the diffusion and acceptance of lithium in an anode are improved, and superior cycle characteristics can be obtained.

Abstract: Provided is an anode for use in electrochemical cells, wherein the anode active layer has a first layer comprising lithium metal and a multi-layer structure comprising single ion conducting layers and polymer layers in contact with the first layer comprising lithium metal or in contact with an intermediate protective layer, such as a temporary protective metal layer, on the surface of the lithium-containing first layer. Another aspect of the invention provides an anode active layer formed by the in-situ deposition of lithium vapor and a reactive gas. The anodes of the current invention are particularly useful in electrochemical cells comprising sulfur-containing cathode active materials, such as elemental sulfur.

Abstract: Disclosed is a nonaqueous electrolytic solution useful for producing a lithium secondary battery having excellent cycle characteristics. Specifically disclosed is a nonaqueous electrolytic solution for lithium secondary batteries obtained by dissolving an electrolyte salt in a nonaqueous solvent which is characterized by containing 0.1 to 10 wt. % of a tert-alkylbenzene compound and also containing 0.001-0.5 wt. % of a benzene compound, wherein a hydrocarbon group having 1-4 carbon atoms is bonded to a benzene ring via the tertiary carbon atom, relative to the tert-alkylbenzene compound.

Abstract: The present invention provides a lithium secondary battery having excellent battery cycle property, electrical capacity, storage characteristic and other battery characteristics for a long period of time, and a nonaqueous electrolytic solution which is usable for the lithium secondary battery. A nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, comprising (i) a dicarbonyl compound represented by the general formula (I), or (ii) a dicarbonyl compound represented by the general formula (II) and vinylene carbonate and the like in the nonaqueous electrolytic solution. (wherein R1 represents a hydrogen atom, an alkyl group, an alkenyl group, a phenyl group or the like; and X represents a hydrogen atom, an R2 group or an OR2 group. R2 represents an alkyl group, an alkenyl group, a phenyl group or the like.

Abstract: A lithium ion secondary battery shows excellent charge/discharge properties and also excellent storage properties. The lithium ion secondary battery includes an aprotic electrolyte containing a sulfonate ester having at least two sulfonyl groups and graphite as principal component of negative electrode active substance layers, the density of the negative electrode active substance layers being not less than 0.90 g/cm3 and not more than 1.65 g/cm3.

Abstract: A nonaqueous electrolytic solution that can provide a high energy density nonaqueous electrolyte secondary battery having a high capacity, excellent storage characteristics, and excellent cycle characteristics and suppressing the decomposition of an electrolytic solution and the deterioration thereof when used in a high-temperature environment includes an electrolyte, a nonaqueous solvent, and a compound represented by general formula (1): wherein R1, R2, and R3 each independently represent a hydrogen atom, a cyano group, or an optionally halogen atom-substituted hydrocarbon group having 1 to 10 carbon atoms, with the proviso that R1 and R2 do not simultaneously represent hydrogen atoms.

Abstract: An electrolyte for a lithium ion secondary battery is provided. The electrolyte includes a non-aqueous organic solvent, a lithium salt, an ionic liquid and an additive. The additive has a lowest unoccupied molecular orbital (LUMO) level of ?0.5 to 1.0 eV and a highest occupied molecular orbital (HOMO) level lower than ?11.0 eV. Further provided is a lithium ion secondary battery including the electrolyte. The battery is advantageous in terms of overcharge safety and heat stability. In addition, the battery has improved high-efficiency properties and cycle life characteristics.