Positive electrode materials combining high safety and high power in a Li rechargeable battery

摘要

The invention relates to a Li_aNi_xCo_yMn_y′M′_zO₂ composite oxide for use as a cathode material in a rechargeable battery, with a non-homogenous Ni/M′ ratio in the particles, allowing excellent power and safety properties when used as positive electrode material in Li battery. More particularly, in the formula 0.9a1.1, 0.3≦x≦0.9, 0y≦0.4, 0y′≦0.4, 0z≦0.35, e0.02, 0≦f≦0.05 and 0.9(x+y+y′+z+f)1.1;;M′ consists of either one or more elements from the group Al, Mg, Ti, Cr, V, Fe, Mn and Ga; N consists of either one or more elements from the group F, Cl, S, Zr, Ba, Y, Ca, B, Sn, Sb, Na and Zn. The powder has a particle size distribution defining a D10, D50 and D90; and the x and z parameters varying with the particles size of the powder, and is characterized in that either one or both of:x1−x2≧0.005andz2−z1≧0.005;x1 and z1 being the parameters corresponding to particles having a particle size D90; and x2 and z2 being the parameters corresponding to particles having a particle size D10.