DOPING OF CO3O4 WITH LITHIUM BY A SOLID-STATE REACTION IN AIR .1. OXIDATION DEGREE AND COORDINATION OF CATIONS

By solid state reaction between cobalt and lithium salts in air at 500-750°C spinels of the type LiyLixCo3-xO4 were obtained, the indices x and y referring to Li+ ions occupying, respectively, sites and interstices in the spinel lattice. The Lix+ ions are in the A-sublattice, and charge compensation is achieved by Lix+-Li+y pairs and Co4+(B)-ions. At 500°C (x + y) < 0.3 and the maximum amount of Co4+ ions per spinel formula unit is (x-y)max∼-0.08. The amount of Li+ ions in spinel interstices increases with rising preparation temperature, Co4+ decreasing. At 750°C the Li+ concentrations in spinel sites and interstices are the same, (x + y) < 0.22. © 1990.