Thin film Li-LiMn/sub 2/O/sub 4/ batteries

Abstract

Thin-film rechargeable Li-LiMn/sub 2/O/sub 4/ batteries have been fabricated and characterized. Following deposition, by electron beam evaporation of LiMn/sub 2/O/sub 4/, the amorphous as-deposited cathode films 1 cm/sup 2/ in area by 0.3 to 4 /spl mu/m thick were annealed at 700/spl deg/C to 800/spl deg/C in oxygen in order to form the crystalline spinel phase. The capacity of the cells between 4.5 V to 3.8 V depended on the annealing conditions and ranged from 50 /spl mu/Ah/mg to 120 /spl mu/Ah/mg. When cycled over this range, the batteries exhibited excellent secondary performance with capacity losses as low as 0.001% per cycle. On charging to 5.3 V, a plateau with a median voltage of 5.1 V was observed. The total charge extracted between 3.8 V to 5.3 V corresponded to about 1Li/Mn/sub 2/O/sub 4/.< >