LI+ INSERTION INTO MN SPINEL PHASES
Abstract Partly substituted and unsubstituted Mn spinels have been synthesized at temperatures of 350–450°C. The inclusion of Cr ions in the cubic spinel structure is particularly effective in catalyzing its formation at low temperature. A spinel of composition LiMn 2− x Cr x O 4.35 ( x ∼0.2–0.4), prepared at 350–370°C, has a defective structure of low-crystallinity and a high surface area. It can be cycled at 1 mA cm 2 (∼ C 3 ) with a stabilized capacity of 0.13 Ah/g. Analogous spinels prepared at 450°C, with or without Cr, have inferior performances. The Li + diffusion coefficient in the Cr-containing spinel is higher than that of the unsubstituted material.