MECHANOCHEMICAL PREPARATION AND DEGRADATION OF LICOO2

A phase structurally related to LiCoO//2 (03) was obtained by comminution of stoichiometric mixtures of LiOH multiplied by (times) H//2O and Co(OH)//2 for 10 h. This process took place without the occurrence of Co//3O//4 as an intermediate, in constrast with the thermal behavior of LiOH multiplied by (times) H//2O-Co(OH)//2 mixtures. More prolonged mechanical treatment of this sample resulted in the elimination of lithium from the LiCoO//2 structure and the occurrence of Co//3O//4 after thermal treatment of the sample. These results are interpreted in terms of the presence of poorly crystallized Co//3O//4 and/or a small amount of H** plus replacing Li** plus in the structure of the LiCoO//2 after grinding for 40 h. Additionally, the mechanical activation of the LiCoO//2 prepared at high temperature leads to a redistribution of cations, evidenced by the formation of Co//3O//4.