Improvement in the cycling performance of LiMn2O4 by the substitution of Fe for Mn

We tried to improve the cycling performance of LiMn2O4 by substituting Fe for Mn. LiFe0.25Mn1.75O4 is the optimum composition which has a relatively large discharge capacity and the largest discharge capacity at n = 30, and the smallest percentage of capacity deterioration at n = 30, especially with (C-1 - C-30) X 100/C-1 = 5.6%. The variation of discharge capacities for the LiFeyMn2-yO4 (y = 0.0, 0.1, 0.25, 0.38, and 0.5) with cycling can be well expressed by the following equation: C-n/C-o = e(-ktn) where C-n is the discharge capacity at nth cycle, C-0 the theoretical capacity, t=t(1) + t(2) + ... +t(n) (t(n) = discharging time at nth cycle), and k and n constants. (C) 1998 Published by Elsevier Science B.V. All rights reserved.