| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a negative electrode active material having superior cycle characteristics and high charge and discharge capacity as a substitute for graphite, to provide a negative electrode using the active material, and to provide a lithium ion secondary battery. <P>SOLUTION: This negative electrode active material for the lithium ion secondary battery contains CaSi<SB>2</SB>of which a crystal structure is R-3m (Z=6), and contains 50 wt% or more of the CaSi<SB>2</SB>. Furthermore, as for the negative electrode active material, it is preferable that the average particle diameter is 2-30 μm, and 10% cumulative diameter in the particle size distribution on a volumetric basis is 1-5 μm, and 90% cumulative diameter in the distribution is 5-70 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT |
