Abstract: A secondary battery both having a cathode and an anode with a separator in between. The cathode comprises a stable complex oxide LixNi1-y-zMnyMIzO2 and a highly conductive complex oxide LisMIIl-t-uMntMIIIuO2. Each of MI and MIII includes at least one kind selected from the group consisting of elements in Group 2 through Group 14, and MII includes at least one kind selected from the group consisting of Ni and Co, and the values of x, y, z, s, t and u are within a range of 0.9?x?1.1, 0.25?y?0.45, 0.01?z?0.30, 0.9?s?1.1, 0.05?t?0.20, and 0.01?u?0.10, respectively.

Abstract: A positive electrode for a rechargeable lithium battery including a net-type current collector and a positive active material layer formed on both sides of the current collector and also including a positive active material and a binder and having a thickness of about 150 ?m or more, a method of manufacturing the same, and a rechargeable lithium battery including the same.

Abstract: A battery includes an electrolyte activating one or more anodes and one or more cathodes. The electrolyte includes one or more salts in a solvent. One or more of the cathodes has a cathode medium that includes a lithium transition metal oxide as a cathode active material. The cathode medium also includes an inactive material that reacts with the electrolyte to form a passivation layer on the cathode medium. The passivation layer can include LiF. In some instances, the inactive material includes or consists of Li2CO3.

Abstract: Exemplary flexible thin film solid state lithium ion batteries (10) and methods for making the same are disclosed. An exemplary flexible solid state thin film electrochemical device (10) may include a flexible substrate (12), first (14) and second electrodes (18), and an electrolyte (16) disposed between the first (14) and second electrodes (18). The electrolyte (16) is disposed on the flexible substrate (12). The first electrode (14) is disposed on the electrolyte (16), and the second electrode (18) having been buried between the electrolyte (16) and the substrate (12).

Abstract: A nonaqueous electrolyte secondary battery including: an electrode group which includes a positive electrode containing lithium-containing composite oxide, a negative electrode capable of inserting and extracting lithium ions, and a porous insulator interposed between the positive electrode and the negative electrode, and is sealed in a battery case together with a nonaqueous electrolyte, wherein the porous insulator has a Gurley number of 100 sec/100 ml to 1000 sec/100 ml, both inclusive, and an average pore diameter of 0.05 ?m to 0.15 ?m, both inclusive.

Abstract: The present invention improves the cycle characteristics of a non-aqueous electrolyte secondary cell that uses lithium cobalt oxide as a positive electrode active material. To this end, an element different from cobalt such as zirconium and titanium is added to the lithium cobalt oxide, acting as the positive electrode active material. The non-aqueous electrolyte contains a non-aqueous solvent containing diethyl carbonate at 10 to 30 volume percent on a base of 25 degree Celsius and contains an electrolyte salt.

Abstract: As an alternative technique to lead-acid batteries, the present invention provides an inexpensive 2 V non-aqueous electrolyte secondary battery having excellent cycle life at a high rate by preventing volume change during charge and discharge. The non-aqueous electrolyte secondary battery uses: a positive electrode active material having a layered structure, being represented by chemical formula Li1±?[Me]O2, where 0??<0.2, and Me is a transition metal including Ni and at least one selected from the group consisting of Mn, Fe, Co, Ti and Cu, and including elemental nickel and elemental cobalt in substantially the same ratio; and a negative electrode active material including Li4Ti5O12(Li[Li1/3Ti5/3]O4).

Abstract: A method for producing a lithium-containing transition metal oxide represented by the general formula: Li[Lix(NiaM1?a)1?x]O2 where M is metal other than Li and Ni, 0?x, and 0<a. The method includes: (i) mixing a transition metal compound containing Ni and M in a molar ratio of a:(1?a) with lithium carbonate in a predetermined ratio; (ii) causing the temperature of the mixture to reach a predetermined temperature range while repeatedly raising and lowering the temperature thereof; and (iii) thereafter reacting the transition metal compound with the lithium carbonate in the predetermined temperature range.

Abstract: A nonaqueous electrolytic secondary cell produced at low cost and having a large capacity comprises a negative electrode having an active material mainly composed of a material that at least absorbs and releases lithium ions or metallic lithium, a positive electrode, and an electrolyte. The active material of the positive electrode is an oxide containing nickel, manganese, and cobalt, and the contents of the elements are substantial the same.

Abstract: A micro electrical-mechanical systems (MEMS) device INCLUDES a MEMS substrate and at least one MEMS structure on the MEMS substrate. In addition, there is at least one battery cell on the MEMS substrate coupled to the at least one MEMS structure. The at least one battery cell includes a support fin extending vertically upward from the MEMS substrate and a first electrode layer on the support fin. In addition, there is an electrolyte layer on the cathode layer, and a second electrode layer on the electrolyte layer. The support fin may have a height greater than a width. The first electrode layer may have a processing temperature associated therewith that exceeds a stability temperature associated with the second electrode layer.

Abstract: A new design for a cathode having a configuration of: SVO/first current collector/CFx/second current collector/SVO is described. The two cathode current collectors are vertically aligned one on top of the other in a middle region or zone of the cathode. This coincides to where a winding mandrel will be positioned to form a wound electrode assembly with an anode. The overlapping region of the two current collectors helps balance the expansion forces of the exemplary SVO and CFx active material layers. This, in turn, helps maintain a planar cathode that is more amenable to downstream processing. The use of two current collectors on opposite sides of an intermediate cathode active material also provides for enhanced reliability when cathodes are wound from the center as they lend structural integrity to outer portions of the wind.

Abstract: A battery pack includes nonaqueous electrolyte batteries each comprising a positive electrode and a negative electrode. The positive electrode contains a lithium-transition metal oxide having a layered crystal structure. The negative electrode contains a lithium-titanium composite oxide having a spinel structure. And the positive electrodes and the negative electrodes satisfy the formula (1) given below: 1.02?X?2??(1) where X is a ratio of an available electric capacity of each of the negative electrodes at 25° C. to an available electric capacity of each of the positive electrodes at 25° C.

Abstract: A rechargeable lithium-ion battery includes a positive electrode that includes a first current collector and a first active material. The battery also includes an electrolyte and a negative electrode that includes a second current collector and a second active material, where the second active material includes a lithium titanate material. The positive electrode has a first capacity and the negative electrode has a second capacity, the second capacity being less than the first capacity such that the rechargeable lithium-ion battery is negative-limited.

Abstract: There is provided a lithium secondary battery having a high capacity and excellent high-rate discharge characteristic and charge/discharge cycle characteristic. The lithium secondary battery comprises a negative electrode, a positive electrode and an ionic conductor, wherein the positive electrode comprises lithium metal composite oxide particles; the lithium metal composite oxide particles comprise a plurality of secondary particles in an elongated shape each comprised of a plurality of primary particles with an average particle size of 0.1 to 1 ?m so aggregated as to form a void therebetween; and the secondary particle is columnar or planar and has an average size in a long length direction of 5 to 15 ?m.

Abstract: In a lithium transition metal oxide having a layered structure, one is provided, which is particularly excellent as a positive electrode active material of a battery on board of an electric vehicle or a hybrid vehicle in particular. A lithium transition metal oxide having a layered structure is proposed, wherein the ratio of the crystallite diameter determined by Measurement Method 1 according to the Rietveld method with respect to the mean powder particle diameter (D50) determined by the laser diffraction/scattering-type particle size distribution measurement method is 0.05 to 0.20.

Abstract: Disclosed herein is a Li-ion cell comprising a cathode, an anode, and a separator disposed between the cathode and the anode, wherein the cathode comprises Li-ion cathode active material, and the anode comprises Li-ion anode active material and an additive which has an energy density greater than that of the Li-ion anode active material and which is capable of reacting irreversibly with Li-ions.

Abstract: A nonaqueous electrolyte battery includes a positive electrode containing a lithium-transition metal oxide having a layered crystal structure; a negative electrode containing a lithium-titanium composite oxide having a spinel structure; and a nonaqueous electrolyte. The positive electrode and the negative electrode satisfy the formula (1) given below: 1.25?X??(1), where X is a ratio of an available electric capacity, represented by “(B/A)”, A is an available electric capacity (mAh) at 25° C. per cm2 of the positive electrode, and B is an available electric capacity (mAh) at 25° C. per cm2 of the negative electrode.

Abstract: Disclosed herein is a cathode active material based on lithium nickel-manganese-cobalt oxide represented by Formula 1, wherein the lithium nickel-manganese-cobalt oxide has nickel content of at least 40% among overall transition metals and is coated with an ion-conductive solid compound at a surface thereof. A lithium secondary battery having the disclosed cathode active material has advantages of not deteriorating electrical conductivity while maintaining high temperature stability, so as to efficiently provide high charge capacity.

Abstract: A high capacity, high charge rate lithium secondary cell includes a high capacity lithium-containing positive electrode in electronic contact with a positive electrode current collector, said current collector in electrical connection with an external circuit, a high capacity negative electrode in electronic contact with a negative electrode current collector, said current collector in electrical connection with an external circuit, a separator positioned between and in ionic contact with the cathode and the anode, and an electrolyte in ionic contact with the positive and negative electrodes, wherein the total area specific impedance for the cell and the relative area specific impedances for the positive and negative electrodes are such that, during charging at greater than or equal to 4 C, the negative electrode potential is above the potential of metallic lithium.

Abstract: According to one embodiment, there is provided a nonaqueous electrolyte battery. The negative electrode of the battery includes a negative electrode active material which can absorb and release lithium ions at a negative electrode potential of 0.4 V (V.S. Li/Li+) or more. The battery satisfying the following equations (I) and (II): 1?Q2/Q1 ??(I) 0.5?C/A?0.

Abstract: The object of the invention is to provide positive electrode material in which a discharge rate characteristic and battery capacity are hardly deteriorated in the environment of low temperature of ?30° C., its manufacturing method and a lithium secondary battery using the positive electrode material. The invention is characterized by the positive electrode material in which plural primary particles are flocculated and a secondary particle is formed, and the touch length of the primary particles is equivalent to 10 to 70% of the length of the whole periphery on the section of the touched primary particles.

Abstract: Provided is a positive electrode active material for a lithium ion battery, wherein the oil absorption of NMP (N-methylpyrrolidone) measured with a method that is compliant with JIS K5101-13-1 is 30 mL or more and 50 mL or less per 100 g of powder, and wherein [the positive electrode active material] is represented with LiaFewNixMnyCozO2 (1.0<a/(w+x+y+z)<1.3, 0.8<w+x+y+z<1.1) having a spinel structure or a layered structure, and includes at least three or more components among the components of Fe, Ni, Mn, and Co.

Abstract: Disclosed herein is a cathode active material based on lithium nickel-manganese-cobalt oxide represented by Formula 1, wherein the lithium nickel-manganese-cobalt oxide has a nickel content of at least 40% among overall transition metals and is coated with a conductive polymer at a surface thereof. A lithium secondary battery having the disclosed cathode active material has advantages of not deteriorating electrical conductivity while enhancing high temperature stability, so as to efficiently provide high charge capacity.

Abstract: A cathode active material capable of improving chemical stability, a method for producing the same, and a nonaqueous electrolyte secondary battery using the same which has high capacity and good charge-discharge cycling characteristics is provided. The cathode has a cathode active material. The cathode active material includes a coating layer formed on at least a part of the composite oxide particle, the coating layer including an oxide including lithium and an oxide including a coating element of nickel, or nickel and manganese, and a surface layer formed on at least a part of the coating layer and containing molybdenum.

Abstract: According to one embodiment, a positive electrode includes a positive electrode layer and a positive electrode current collector. The positive electrode layer includes a positive electrode active material including a first oxide represented by the following formula (?) and/or a second oxide represented by the following formula (?). The positive electrode layer has an intensity ratio falling within a range of 0.25 to 0.7. The ratio is represented by the following formula (1) in an X-ray diffraction pattern obtained by using CuK? radiation for a surface of the positive electrode layer.

Abstract: A nonaqueous electrolyte battery of the present invention includes a positive electrode having a positive active material capable of intercalating and deintercalating a lithium ion, a negative electrode having a negative active material capable of intercalating and deintercalating a lithium ion, a separator interposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte. The heat generation starting temperature of the positive electrode is 180° C. or higher. The separator includes heat-resistant fine particles and a thermoplastic resin. The proportion of particles with a particle size of 0.2 ?m or less in the heat-resistant fine particles is 10 vol % or less and the proportion of particles with a particle size of 2 ?m or more in the heat-resistant fine particles is 10 vol % or less. The separator effects a shutdown in the range of 100° C. to 150° C.

Abstract: Each of: (1) a nanoparticle comprising a substantially single crystalline mesoporous Co3O4 material; (2) a battery electrode comprising a plurality of nanoparticles comprising the substantially single crystalline mesoporous Co3O4 material; (3) a battery comprising the battery electrode comprising the plurality of nanoparticles comprising the substantially single crystalline mesoporous Co3O4 material; and (4) a plurality of methods for preparing the nanoparticle comprising the substantially single crystalline mesoporous Co3O4 material, may be employed within the context of a lithium containing battery, such as a lithium ion battery. When the substantially single crystalline mesoporous Co3O4 material has a pore size of about 3 to about 8 nanometers enhanced lithium containing battery electrical performance properties are observed.

Abstract: An energy storage device includes a first electrode comprising a first material and a second electrode comprising a second material, at least a portion of the first and second materials forming an interpenetrating network when dispersed in an electrolyte, the electrolyte, the first material and the second material are selected so that the first and second materials exert a repelling force on each other when combined. An electrochemical device, includes a first electrode in electrical communication with a first current collector; a second electrode in electrical communication with a second current collector; and an ionically conductive medium in ionic contact with said first and second electrodes, wherein at least a portion of the first and second electrodes form an interpenetrating network and wherein at least one of the first and second electrodes comprises an electrode structure providing two or more pathways to its current collector.

Abstract: Mesoporous electrode materials with large particle size where the majority of particles have sizes in excess of 15 ?m have a well connected internal mesopore network, and have high power capability when used as intercalation materials for a range of battery and supercapacitor chemistries that rely on intercalation mechanisms to store charge.

Abstract: An all-solid secondary battery having excellent output characteristics and cycle characteristics, and a positive electrode used therefor includes a positive electrode active material which includes LiMeO2. The Me includes at least one metal element. A variation rate of the lattice constant a and a variation rate of the lattice constant c between LiMeO2 before the deintercalation of Li and Li1-xMeO2 (0<X<0.8) after the deintercalation of Li are 1% or less, respectively.

Abstract: Provided is a non-aqueous electrolyte capable of favorably suppressing the gas generation during storage in a high temperature environment and during charge/discharge cycling of a non-aqueous electrolyte secondary battery. The non-aqueous electrolyte includes a non-aqueous solvent and a solute dissolved in the non-aqueous solvent, wherein: the non-aqueous solvent includes ethylene carbonate, propylene carbonate, diethyl carbonate, and an additive; the additive includes a sultone compound and a cyclic carbonate having a C?C unsaturated bond; a weight percentage WPC of the propylene carbonate relative to a total of the ethylene carbonate, propylene carbonate, and diethyl carbonate is 30 to 60% by weight; a ratio WPC/WEC of the weight percentage WPC of the propylene carbonate to a weight percentage WEC of the ethylene carbonate relative to the total satisfies 2.

Abstract: Provided is a non-aqueous electrolyte-based, high-power lithium secondary battery having a long service life and superior safety at both room temperature and high temperature, even after repeated high-current charging and discharging. The battery comprises a mixture of a lithium/manganese spinel oxide having a substitution of a manganese (Mn) site with a certain metal ion and a lithium/nickel/cobalt/manganese composite oxide, as a cathode active material.

Abstract: A process for preparing lithium-nickel-manganese-cobalt composite oxide used as a positive electrode material for the lithium ion battery, comprising subjecting a mixture containing a lithium compound and nickel-manganese-cobalt hydroxide to a first-stage sintering and a second-stage sintering. The process includes adding a binder and/or binder solution after the first-stage sintering, and the mixture of the binder and/or binder solution and the product of first-stage sintering is sintered in the second-stage sintering. The tap density and volume specific capacity of the positive electrode material lithium-nickel-manganese-cobalt composite oxide prepared by the process, come up to 2.4 g/cm3 and 416.4 mAh/cm3, respectively. Besides, the positive electrode material lithium-nickel-manganese-cobalt composite oxide prepared by the process possesses the advantages of high specific capacity and good cycle stability.

Abstract: The present invention intends to improve the intermittent cycle characteristics in a lithium ion secondary battery including, as a positive electrode active material, a lithium composite oxide mainly composed of nickel or cobalt. The present invention is a lithium ion secondary battery wherein the positive electrode includes active material particles including a lithium composite oxide. The lithium composite oxide is represented by the general formula (1): LixM1-yLyO2 (where 0.85?x?0?y?0.50, and element M is at least one selected from the group consisting of Ni and Co, and element L is at least one selected from the group consisting of alkaline earth elements, transition metal elements, rare earth elements, Group IIIb elements and Group IVb elements). The surface layer of the active material particles includes element Le being at least one selected from the group consisting of Al, Mn, Ti, Mg, Zr, Nb, Mo, W and Y. The active material particles are surface-treated with a coupling agent.

Abstract: To provide a process for producing a surface modified lithium-containing composite oxide, which is excellent in discharge capacity, volume capacity density, safety, durability for charge and discharge cycles and an excellent rate property, at a low production cost. The present invention is characterized in that a process for producing a surface modified lithium-containing composite oxide, wherein a lithium titanium composite oxide is contained in the surface layer of particles of a lithium-containing composite oxide represented by the formula: LipNxMyOzFa, where N is at least one element selected from the group consisting of Co, Mn and Ni, M is at least one element selected from the group consisting of Al, Sn, alkaline earth metal elements and transition metal elements other than Co, Mn and Ni, 0.9?p?1.3, 0.9?x?2.0, 0?y?0.1, 1.9?z?4.2, and 0?a?0.

Abstract: A non-aqueous electrolyte battery that contains a molten salt electrolyte and has the enhanced output performances and cycle performances can be provided. The electrolyte has a molar ratio of lithium salt to molten salt of from 0.3 to 0.5, and the non-aqueous electrolyte battery has a positive electrode having a discharge capacity of 1.05 or more times that of a negative electrode thereof.

Abstract: A LiCoO2-containing powder. and a method for preparing a LiCoO2-containing powder, includes LiCoO2 having a stoichiometric composition via heat treatment of a lithium cobalt oxide and a lithium buffer material to make an equilibrium of a lithium chemical potential therebetween; the lithium buffer material which acts as a Li acceptor or a Li donor to remove or supplement a Li-excess or a Li-deficiency, the lithium buffer material coexisting with the stoichiometric lithium metal oxide. Also an electrode includes the LiCoO2-containing powder as an active material, and a rechargeable battery includes the electrode.

Abstract: The present invention provides an olivine-type positive active material precursor for a lithium battery that includes MXO4-zBz (wherein M is one element selected from the group consisting of Fe, Ni, Co, Mn, Cr, Zr, Nb, Cu, V, Ti, Zn, Al, Ga, Mg, B, and a combination thereof, X is one element selected from the group consisting of P, As, Bi, Sb, and a combination thereof, B is one element selected from the group consisting of F, S, and a combination thereof, and 0?z?0.5) particles, and the precursor has a particle diameter of 1 to 20 ?m, a tap density of 0.8 to 2.1 g/cm3, and a specific surface area of 1 to 10 m2/g. The olivine-type positive active material prepared using the olivine-type positive active material precursor has excellent crystallinity of particles, a large particle diameter, and a high tap density, and therefore shows excellent electrochemical characteristics and capacity per unit volume.

Abstract: Active material particles of a lithium ion secondary battery includes at least a first lithium-nickel composite oxide: LixNi1-y-zCoyMezO2 (where 0.85?x?1.25, 0<y?0.5, 0?z?0.5, 0<y+z?0.75, and element Me is at least one selected from the group consisting of Al, Mn, Ti, Mg, and Ca) forming a core portion thereof. The surface layer portion of the active material particles includes nickel oxide having the NaCl-type crystal structure or a second lithium-nickel composite oxide, and further includes element M not forming the crystal structure of the first lithium-nickel composite oxide. Element M is at least one selected from the group consisting of Al, Mn, Mg, B, Zr, W, Nb, Ta, In, Mo, and Sn.

Abstract: A lithium-ion battery includes a positive electrode having an active material and a polymeric separator configured to allow electrolyte and lithium ions to flow between a first side of the separator and an opposite second side of the separator. The battery also includes a liquid electrolyte having a lithium salt dissolved in at least one non-aqueous solvent and a negative electrode having a lithium titanate active material. The positive electrode has a first capacity and the negative electrode has a second capacity that is less than the first capacity.

Abstract: A nonaqueous electrolyte secondary battery of the present invention includes a positive electrode plate 21 having an uncoated part along at least one long side of a continuous positive electrode substrate 211 coated with a positive electrode mixture layer 212 containing a positive electrode active material. In the nonaqueous electrolyte secondary battery, the positive electrode mixture layer 212 includes a lithium transition-metal compound capable of insertion and separation of lithium ion and 5 to 15% by mass of a conductive material with respect to the positive electrode mixture, the conductive material contains 70% by mass or more of flaked graphite particles with an average particle diameter (D50) of 5 to 30 ?m and an average thickness of 0.1 to 1.0 ?m with respect to the whole amount of the conductive materials, and a packing density of the positive electrode mixture layer is 2.00 to 2.80 g/cc.

Abstract: Embodiments of the present invention are directed to electrode assemblies and secondary batteries using the same. The secondary battery includes an electrode assembly including a positive electrode having a positive active material, a negative electrode including a negative active material, and a separator between the positive and negative electrodes. The positive active material includes a lithium composite oxide represented by LiCO1?x?yMgxTiyO2 where 0.0056?x?0.0089, and 0.0029?y?0.0045. The electrode assembly and the lithium secondary battery including the same show good discharge efficiency even with increases in C-rate, and substantially prevent reductions in battery capacity resulting from battery deterioration, thereby improving battery lifespan.

Abstract: A method of producing a passivated thin film material is disclosed wherein an insulating thin film layer (10), having pinholes (12) therein, is positioned upon an underlying electrically conductive substrate (11). The thin film layer is then electroplated so that the pinholes are filled with a reactive metal. The thin film layer and substrate are then immersed within a silicon doped tetramethylammonium hydroxide (TMAH) solution. Excess silica within the solution precipitates onto the top surfaces of the aluminum plugs (13) to form an electrically insulative cap which electrically insulates the top of the aluminum plug. As an alternative, the previously described metal plugs may be anodized so that at least a portion thereof becomes an oxidized metal which is electrically insulative.

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 nonaqueous electrolyte secondary battery includes a positive electrode containing a positive active material, a negative electrode containing a negative active material and a nonaqueous electrolyte. Characteristically, the positive active material comprises a mixture of a lithium transition metal complex oxide A obtained by incorporating at least Zr and Mg into LiCoO2 and a lithium transition metal complex oxide B having a layered structure and containing at least Ni and Mn as the transition metal.

Abstract: A lithium-ion battery includes a positive electrode that includes a positive current collector, a first active material, and a second active material. The lithium-ion battery also includes a negative electrode comprising a negative current collector, a third active material, and a quantity of lithium in electrical contact with the negative current collector. The first active material, second active material, and third active materials are configured to allow doping and undoping of lithium ions, and the second active material exhibits charging and discharging capacity below a corrosion potential of the negative current collector and above a decomposition potential of the first active material.

Abstract: A composition comprising: a) a lithiated oxide of transition metals containing at least nickel, cobalt and aluminium; b) a lithiated phosphate of at least one transition metal, the surface of which is at least partially covered by a layer of carbon, the proportion by mass of the lithiated oxide of transition metals containing at least nickel, cobalt and aluminium, being less than or equal to 10 % of the weight of the composition. the proportion by mass of the lithiated phosphate of at least one transition metal being greater than or equal to 90 % of the weight of the composition. A lithium-ion or lithium-polymer type accumulator comprising at least one positive electrode containing this composition.

Abstract: A lithium-ion battery includes a positive electrode having a first active material and a second active material and a negative electrode including a third active material. The second active material includes a lithiated form of a material that does not include electrochemically cyclable lithium in the as-provided state.

Abstract: Disclosed is a positive electrode active material for a nonaqueous electrolyte secondary battery having at least a lithium-transition metal composite oxide of a layer structure, in which an existence ratio of at least one selected from the group consisting of elements which may become tetravalent and magnesium is 20% or more on a surface of the lithium-transition metal composite oxide. By use of this positive electrode active material, a nonaqueous electrolyte secondary battery having excellent battery characteristics, specifically, having excellent high rate characteristics, cycle characteristics, low-temperature characteristics, thermal stability, and the like, under the even more harsh environment for use can be realized.

Abstract: An electrolyte for a lithium secondary battery is provided. The electrolyte improves battery safety, high temperature storage characteristics, and electrochemical properties of lithium batteries. The electrolyte comprises at least one lithium salt and a non-aqueous organic solvent comprising a cyclic carbonate and a lactone-based compound. The lactone based compound comprises substituents selected from the group consisting of alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and combinations thereof. A lithium battery is also provided, which comprises a negative electrode capable of intercalating/deintercalating lithium, a positive electrode capable of intercalating/deintercalating lithium, and an inventive electrolyte.