Fluorine doping of spherical spinel LiMn2O4

Fluorine-doped spherical spinel LiMn2O4 was prepared by controlled crystallization from cheap carbonates. The fluorine bulk and surface doping of spherical samples showed different effects at the same doping amount. 5% fluorine surface-doped sample with Li/Mn = 1.15/2 presented both good cycleability and high tap density of 2.1 g cm(-3) Its initial specific capacities were 111 and 104 mA h g(-1) at 25 and at 55 degrees C, respectively. Its capacity retentions reached 98.2% and 87.5% at 25 and at 55 degrees C, respectively, at 50th cycle. There was small difference between the capacity at 25 and 55 degrees C during cycling. This is of practical value to the enhancement of overall performance of LiMn2O4 both at room temperature and at elevated temperature. (c) 2005 Elsevier B.V. All rights reserved.