NEW PROCESS FOR LOW-TEMPERATURE PREPARATION OF LINI1-XCOXO2 CATHODE MATERIAL FOR LITHIUM CELLS

LiNi1-yCoyO2 has been prepared at a temperature as low as 400 degrees C by molten ion exchange using a beta Ni1-yCoyOOH and either LiNO3 or LIOH. The mechanism of these reactions was clarified using DTA and TG analyses. The material prepared using the LiNO3 is well crystallized b ecause the reaction takes place in viscous state since LiNO3 melts and then reacts with the oxyhydroxide. However, in the case of using LiOH , a solid-solid diffusion reaction takes place and leads to a material with broad XRD peaks. The electrochemical characteristics of these ma terials were evaluated and compared with those prepared by the usual p rocesses at high temperature.