COMPOSITE PARTICLES, METHOD FOR PRODUCING SAME, ELECTRODE MATERIAL FOR SECONDARY BATTERIES, AND SECONDARY BATTERY

摘要

Provided is a positive electrode material for lithium ion secondary batteries that are highly safe and can be charged and discharged with a large current, while having long service lives. Composite particles, each of which is obtained by coating a lithium-containing phosphate particle with a carbon film that contains one or more carbon materials selected from the group consisting of (i) fibrous carbon materials, (ii) chain-like carbon materials and (iii) carbon materials that are obtained by connecting a fibrous carbon material and a chain-like carbon material with each other. It is preferable that each fibrous carbon material is a carbon nanotube having an average fiber diameter of 5-200 nm. It is preferable that each chain-like carbon material is carbon black wherein primary particles having an average particle diameter of 10-100 nm are bonded together in a chain form. It is preferable that the lithium-containing phosphate is LiFePO4, LiMnPO4, LiMnXFe(1-X)PO4, LiCoPO4 or Li3V2(PO4)3.