POSITIVE PLATE ACTIVE MATERIAL, METHOD FOR PRODUCING THE SAME, AND SECONDARY CELL

摘要

A positive plate active material for lithium ion secondary cells mainly containing an Li-Mn composite oxide particles having a spinel structure wherein the average of the porosity (A/B) x 100 (%) (1) (where A is the total cross sectional area of the pores included in a cross section of one secondary particle, and B is the cross sectional area of one secondary particle) of the particles is 15% or less, the tap density is 1.9 g/ml or more, the crystallite size is 400-900 A, and the lattice constant is 8.240 A or less. A method for producing the positive plate active material and a lithium ion secondary cell comprising the positive plate active material are also disclosed. The particles of the positive plate active material are dense and spherical. The packability of the particles in an electrode is excellent. The initial capacity and capacity maintenance factor of the secondary cell are high even in a high-temperature environment.