Seiko Instruments Inc

Seiko Electronic Components Ltd.

Seiji Yahagi

Fumiharu Iwasaki

Tsugio Sakai

Kensuke Tahara

Akifumi Sakata

Hideki Ishikawa

Shinichi Takasugi

A non-aqueous electrolyte secondary battery comprises a negative electrode having an active material comprised of lithium or a material capable of absorbing and releasing lithium, a lithium ion conductive non-aqueous electrolyte, and a positive electrode. The positive electrode active material is comprised of a composite represented by composition formula Li.sub.a R.sub.b L.sub.c M.sub.d O.sub.2 where R is one or more metalloid elements selected from boron B and silicon Si, L is at least one element selected from metals and metalloids of Groups IIIA and IVA of the periodic table, alkaline earth metals, and metals selected from the group consisting of Ti, Mn, Cu and Zn, M represents transition metal elements comprising at least Ni and Co, R, L and M are different, and a, b, c and d satisfy 0&lt;a.ltoreq.1.15, 0.85.ltoreq.b+c+d.ltoreq.1.3, 0&lt;b+c.ltoreq.0.5, 0&lt;b and 0.ltoreq.c.

Non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery has a negative electrode, a positive electrode and a non-aqueous electrolyte with lithium ion conductivity. A composite oxide containing lithium represented by composition formula Li.sub.x Si.sub.1-y M.sub.y O.sub.z (where M is one or more kinds of elements selected from metals other than alkaline metals, and metalloids other than silicon, and x, y and z satisfy O.ltoreq.x, 0&lt;y&lt;1, and 0&lt;z&lt;2) is used as an active material for the negative electrode. The battery exhibits a negative active material with a lower and baser potential and a large charging/discharging capacity to produce a long cycle service life secondary battery which facilitates a large current charging and discharging and reduces deterioration due to excess charging and excess discharging.

Non-aqueous electrolyte secondary battery and method of producing the

A non-aqueous electrolyte secondary battery has a negative electrode, a positive electrode and a non-aqueous electrolyte with lithium ion conductivity. A composite oxide produced from a metal or a metalloid and lithium represented by composition formula Li.sub.x MO (where M represents metals or metalloids other than alkali metals, and x satisifies 0.ltoreq.x) is used as an active material of one or both of the negative electrode and the positive electrode. The battery exhibits a large charging/discharging capacity and a high energy density together with smaller polarization (internal resistance) on charging and discharging which facilitates a large current charging and discharging with a long cycle life and reduces deterioration due to excess charging and excess discharging.

A non-aqueous electrolyte secondary battery has a negative electrode, a positive electrode and a lithium ion-conductive non-aqueous electrolyte. A silicon oxide or a silicate containing lithium is used as the negative electrode active material. The potential of the negative electrode active material is low, the charge and discharge capacity in a base potential region of 0-1 V with respect to metallic lithium is large, and the polarization (internal resistance) during charge and discharge is small. A secondary battery having a high voltage and a high energy density is obtained in which large current charge and discharge characteristics are facilitated, the deterioration due to excessive charge and excessive discharge is reduced, the cycle life is long and the reliability is high.

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Tokyo, Japan

Seiji Yahagi