Sanyo Electric Co., Ltd.

Noriyuki Shimizu

Yoshinori Kida

Hideki Kitao

Kouichi Sato

A non-aqueous electrolyte secondary battery uses as its positive electrode active material a mixture of a first lithium-containing transition metal oxide containing nickel and manganese as transition metals and having a crystal structure belonging to the space group R3m and a second lithium-containing transition metal oxide containing nickel, cobalt, and manganese as transition metals and having a crystal structure belonging to the space group R3m, or a mixture of the first lithium-containing transition metal oxide and a lithium cobalt oxide. The first lithium-containing transition metal oxide is LiNiMnOwherein 1&#x2266;a&#x2266;1.5, 0.5&#x2266;x+y&#x2266;1, 0&#x3c;x&#x3c;1, and 0&#x3c;y&#x3c;1. The second lithium-containing transition metal oxide is LiNiMnCoOwherein 1&#x2266;b&#x2266;1.5, 0.5&#x2266;p+q+r&#x2266;1, 0&#x3c;p&#x3c;1, 0&#x3c;q&#x3c;1, and 0&#x3c;r&#x3c;1.

Non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte. The positive electrode active material includes a lithium-nickel-manganese composite oxide having a hexagonal layered rock-salt structure that belongs to the space group R-3m, and contains lithium in 3b sites that contain transition metals. The lithium-nickel-manganese composite oxide is represented by the molecular formula Li[LiNiMnM]O, where: 0.2&#x3c;x&#x3c;0.4, 0.12&#x3c;y&#x3c;0.5, 0.3&#x3c;z&#x3c;0.62, and 0&#x2266;a&#x3c;0.5; M is at least one of Mg, Al, Zr, Ti, Nb, W, and Mo; and variables x, y, z, and b satisfy the expressions x&#x3e;(1&#x2212;2y)/3, &#xbc;&#x2266;y/z&#x2266;1.0, 0&#x3c;b/(y+z)&#x2266;0.1, and 1.0&#x2266;x+y+z+b&#x2266;1.1.

A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte. The positive electrode active material includes a lithium-nickel-manganese composite oxide having a hexagonal layered rock-salt structure that belongs to the space group R-3m, and contains lithium in 3b sites that contain transition metals. The lithium-nickel-manganese composite oxide is represented by the molecular formula Li[LiNiMnM]Owhere: 0&#x3c;x&#x3c;0.4, 0.12&#x3c;y&#x3c;0.5, 0.3&#x3c;z&#x3c;0.62, and 0&#x2266;a&#x3c;0.5; M is at least one metal element having a valency of from 2 to 6; and the variables x, y, z, and b satisfy the expressions x&#x3e;(1&#x2212;2y)/3, 1/4&#x2266;y/z&#x2266;1.0, 0&#x3c;b/(y+z)&#x2266;0.1, and 1.0&#x2266;x+y+z+b&#x2266;1.1.

A non-aqueous electrolyte secondary battery has a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte. The positive electrode active material includes a lithium-nickel-manganese composite oxide having a hexagonal layered rock-salt structure that belongs to the space group R-3m, and contains lithium in 3b sites that contain transition metals. The lithium-nickel-manganese composite oxide is represented by the molecular formula Li[LiNiMn]Owhere: 0&#x3c;x&#x3c;0.4, 0.12&#x3c;y&#x3c;0.5, 0.3&#x3c;z&#x3c;0.62, 0&#x2266;a&#x3c;0.5; and the variables x, y, and z satisfy the expressions x&#x3e;(1&#x2212;2y)/3, &#xbc;&#x2266;y/z&#x2266;1.0, and x+y+z=1.0. The balance between input power and output power and power characteristics are improved, and the initial charge-discharge efficiency and discharge capacity are enhanced.

The non-aqueous electrolyte secondary battery of the present invention uses, as the positive electrode active material, a mixture of a lithium-containing transition metal oxide LiNiMnO(wherein a, x, and y respectively satisfy the following relations: 1&#x3c;a&#x2266;1.5; 0.5&#x2266;x+y&#x2266;1; 0&#x3c;x&#x3c;1; and 0&#x3c;y&#x3c;1) containing nickel and manganese as transition metals and having the layered rock-salt type crystal structure of a hexagonal system belonging to space group R-3m and a lithium manganese oxide LiMnO(wherein b satisfies 0&#x2266;b&#x2266;0.33) having the spinel structure.

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Kobe, Japan

Noriyuki Shimizu