THIOSPINELS AS CATHODE FOR LITHIUM SECONDARY BATTERY

The defect thiospinel CuxM2S4 (M=Ti, Cr) has been studied as a cathode material for the lithium secondary battery. Cu0.18Ti2S4 showed a good reversibility with smooth lithium intercalation and deintercalation. When it was cycled at the current density of 1 mA cm-2, the discharge capacity of the first cycle was about 170 mA h g-1, which corresponds to Li1.5Cu0.18Ti2S4. The defect LixCu1-yCr2S4 Was prepared by the reaction of CuCr2S4 and n-butyllithium. The reduced copper metal was deposited on the surface of the compound. This material did not show the reversible electrode reaction. The X-ray diffraction measurements indicated that the copper metal returned to the 8a sites of the spinel framework in the charge process. This copper atom blocks the lithium diffusion via 16c and 8a sites.