| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a battery excellent in battery characteristics by defining the form of a secondary particle which allows the carbon coating to be performed readily even with olivine-based positive electrode micro particles with a high aspect ratio cohering into secondary particles. <P>SOLUTION: The positive electrode material for a lithium ion secondary battery comprises a compound expressed by the formula LiMPO<SB POS="POST">4</SB>, where M represents one or more elements selected from a group consisting of Mg, Al, Ti, Mn, Fe, Co, Ni, Cu, and Zn. Each primary particle of the compound has a form having a short diameter of 200 nm or smaller, and an aspect ratio of 1.5 to 200 inclusive, which is an a ratio of the long diameter of the particle to the short diameter thereof. Further, the primary particles cohere into secondary particles. As to the form of the secondary particles, the primary particles cohere using, as a main portion to close contact with, a portion in the vicinity of the center of the long diameter of the secondary particle, and the maximum diameter of the short diameters of the secondary particle vs. the diameter at the center is 1.2 or larger. <P>COPYRIGHT: (C)2012,JPO&INPIT |
