| 摘要 |
PROBLEM TO BE SOLVED: To increase capacity and improve a charge/discharge cycle characteristic, by applying a conductive material onto a part or the whole of the surface of a negative material formed by applying a second solid phase onto the whole or a part of the periphery of a core particle comprising a first solid phase. SOLUTION: A first solid phase constituting a core particle made of negative material contains at least Si as component elements, and a second solid phase for covering the core particle is a solid solution or an intermetallic compound of a group 2 element, a transition element, a group 12 element, a group 13 element, one or more element in group 14 elements except for C and Si, of the periodic table and Si. The first solid phase contributes to capacity increase of charge/discharge capacity, and the second solid phase contributes to improvement of a charge/discharge cycle characteristic by absorbing and moderating volume expansion or shrinkage during charge/discharge of the first solid phase. A conductive material for covering the negative material is a carbon material such as natural graphite or a metallic material such as Ni, Co, Cu, and preferably these covers 20% or larger of the entire surface area of the negative material. |
