Cation-deficient mixed oxides, Mn-Co, Mn-Fe and Co-Fe, with the spinel
structure have been synthesized by a solution technique; Preliminary
results on electrochemical Li insertion into these compounds are discu
ssed in relation to their structural and chemical characteristics, and
emphasize the strong effect of cation vacancies on their electrochemi
cal properties. The best results were obtained with the Mn-Co system.