Lithium-manganese-oxide thin-film cathodes prepared by plasma-enhanced chemical vapor deposition

Lithium-manganese-oxide thin-film electrodes were fabricated using plasma-enhanced CVD. Process parameters such as flow rates of the reactants, deposition temperature, and RF power were systematically varied to optimise the charge and discharge properties. The thin films are amorphous as found by XRD spectrometry and can be cycled reversibly in the range from 4.5 to 3 V or 4.5 to 2.5 V with maximum capacities of 30 and 39 microAh/cm2 micron, respectively. The capacity fade of the films was about 0.04% per cycle over more than 700 cycles when tested in liquid electrolytes. Films which are optimised for cycling between 4.5 and 3 V demonstrated a near-perfect balance between the charge and discharge capacities during the initial cycle and also showed very small capacity fade in the subsequent cycles. The results indicate that these lithium manganese oxide thin films are good candidates for use as cathodes in thin-film lithium-ion batteries. 26 refs.