POROUS SILICON PARTICLE, POROUS SILICON COMPOSITE PARTICLE, AND METHODS FOR PRODUCING THESE PARTICLES

摘要

PROBLEM TO BE SOLVED: To provide porous silicon particles and porous silicon composite particles which are suitable, for example, for cathode materials for lithium ion batteries which materialize a high capacity and good cycle characteristics.SOLUTION: In a porous silicon particle 1, a plurality of fine silicon particles 3 are conjugated to form continuous voids. The average x of the particle diameters or support diameters of the fine silicon particles is 2 nm to 2 μm, the standard deviation &sgr; of the particle diameters or support diameters of the fine silicon particles is 1-500 nm, and the ratio (&sgr;/x) between the average x and the standard deviation &sgr; is 0.01-0.5 in the porous silicon particle. A porous silicon composite particle has continuous voids formed by the conjugation of a plurality of fine silicon particles and a plurality of silicon compound particles and is provided with similar characteristics.