A positive electrode active material for non-aqueous secondary battery includes core particles containing a lithium transition metal composite oxide, and a covering layer covering, that covers a surface of the core particle. The covering layer contains niobium and carbonate ions, and the carbonate ions are present at a concentration of from 0.2 weight % to 0.4 weight %. The positive electrode active material for non-aqueous secondary battery exhibits infrared absorption peaks at a wavenumber range of from 1320 cm.sup.−1 to 1370 cm.sup.−1, and at a wavenumber range of from 1640 cm.sup.−1 to 1710 cm.sup.−1.

A positive electrode active material for non-aqueous secondary battery includes core particles containing a lithium transition metal composite oxide, and a covering layer covering, that covers a surface of the core particle. The covering layer contains niobium and carbonate ions, and the carbonate ions are present at a concentration of from 0.2 weight % to 0.4 weight %. The positive electrode active material for non-aqueous secondary battery exhibits infrared absorption peaks at a wavenumber range of from 1320 cm.sup.−1 to 1370 cm.sup.−1, and at a wavenumber range of from 1640 cm.sup.−1 to 1710 cm.sup.−1.

Disclosed is a battery cell having a double sealing structure. In particular, the battery cell includes a first sealing portion formed at an outer circumferential surface of a battery case by thermal bonding and a second sealing portion further formed between an electrode assembly and the first sealing portion at at least one side surface of the first sealing portion.

Disclosed is a battery cell having a double sealing structure. In particular, the battery cell includes a first sealing portion formed at an outer circumferential surface of a battery case by thermal bonding and a second sealing portion further formed between an electrode assembly and the first sealing portion at at least one side surface of the first sealing portion.

According to one embodiment, provided is a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a spinel type lithium-manganese composite oxide and a lithium cobalt oxide, which satisfy formula (1): 0.01≤B/(A+B)<0.05. The negative electrode includes a titanium-containing oxide. The nonaqueous electrolyte battery satisfies formula (2): 0.3≤C/D 0.8. A is a weight ratio (wt %) of the spinel type lithium-manganese composite oxide. B is a weight ratio (wt %) of the lithium cobalt oxide. C is a pore specific surface area (m.sup.2/g) of the positive electrode. D is a pore specific surface area (m.sup.2/g) of the negative electrode.

According to one embodiment, provided is a nonaqueous electrolyte battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes a spinel type lithium-manganese composite oxide and a lithium cobalt oxide, which satisfy formula (1): 0.01≤B/(A+B)<0.05. The negative electrode includes a titanium-containing oxide. The nonaqueous electrolyte battery satisfies formula (2): 0.3≤C/D 0.8. A is a weight ratio (wt %) of the spinel type lithium-manganese composite oxide. B is a weight ratio (wt %) of the lithium cobalt oxide. C is a pore specific surface area (m.sup.2/g) of the positive electrode. D is a pore specific surface area (m.sup.2/g) of the negative electrode.

Disclosed are a cathode active material for high voltage lithium secondary batteries and a lithium secondary battery including the same and, more particularly, the present invention relates to a cathode active material for lithium secondary batteries that includes a lithium transition metal oxide having a lithium molar fraction of greater than 1, containing a relative excess of nickel, and having a composition represented by Formula 1 below, wherein the lithium transition metal oxide has a Li.sub.2MnO.sub.3-like structure phase:
Li.sub.1+aNi.sub.bCo.sub.cMn.sub.1−(a+b+c+d)M.sub.dO.sub.2-tA.sub.t  (1) wherein 0.05≦a≦0.2, 0.4≦b≦0.7, 0.1≦c≦0.4, 0≦d≦0.1, and 0≦t<0.2; M is at least one divalent or trivalent metal; and A is at least one monovalent or divalent anion.

Disclosed are a cathode active material for high voltage lithium secondary batteries and a lithium secondary battery including the same and, more particularly, the present invention relates to a cathode active material for lithium secondary batteries that includes a lithium transition metal oxide having a lithium molar fraction of greater than 1, containing a relative excess of nickel, and having a composition represented by Formula 1 below, wherein the lithium transition metal oxide has a Li.sub.2MnO.sub.3-like structure phase:
Li.sub.1+aNi.sub.bCo.sub.cMn.sub.1−(a+b+c+d)M.sub.dO.sub.2-tA.sub.t  (1) wherein 0.05≦a≦0.2, 0.4≦b≦0.7, 0.1≦c≦0.4, 0≦d≦0.1, and 0≦t<0.2; M is at least one divalent or trivalent metal; and A is at least one monovalent or divalent anion.

A positive electrode material, a positive electrode including the same, a lithium battery including the same, and a method of preparing the same are disclosed herein. In some embodiments, a method of preparing a positive electrode active material including forming a first coating layer on a surface of a lithium transition metal oxide represented by Formula 1 using a basic aqueous solution containing a coating element M.sup.1 (where M.sup.1 includes at least one selected from sodium (Na) and aluminum (Al)), dry-mixing the lithium transition metal oxide having the first coating layer formed on a surface thereof, and a raw material containing a coating element M.sup.2 (where M.sup.2 includes boron (B)) and heat treating the mixture to form a second coating layer.

A positive electrode active material contains a lithium composite oxide and a covering material. The lithium composite oxide has a crystal structure that belongs to space group Fd-3m. The ration I.sub.(111)/I.sub.(400) of a first integrated intensity I.sub.(111) of a first peak corresponding to a (111) plane to a second integrated intensity I.sub.(400) of a second peak corresponding to a (400) plane in an XRD pattern of the lithium composite oxide satisfies 0.05≤I.sub.(111)/I.sub.(400)≤0.90. The covering material has an electron conductivity of 10.sup.6 S/m or less.