| 摘要 |
PROBLEM TO BE SOLVED: To improve a charge-discharge cycle characteristic by substantially using amorphous porous oxide powder, in which a product of a total volume of pores with a pore diameter below a specific value and a true density in a helium substitution method ranges within a specific range, as Li ion storage material for a negative electrode. SOLUTION: In porous oxide powder, a product V.d, between a total volume V (cm<3> /g) of pores with a pore diameter of 100 nm or less and a true density (d) (g/cm<3> ) in a helium substitution method lies in the range of 0.1 to 0.5. A product V'.d of a total volume V' of pores with a pore diameter larger than 100 nm and the true density (d) is preferably 0.6 or less. In addition, the ratio of a total volume V" of pores with a pore size of 10 nm or less to the total volume V of pores with a pore size of 100 nm or less is preferably 50% or more. The porous oxide preferably contains one or more kinds of elements selected from among Sn, Fe, W, Nb, Mo and one or more kinds of element selected from among B, Si, Ge, P, As, Sb, V and Zr. |
