Electrochemical characteristics of sputtered lithium manganese oxide thin film for micropower systems

Abstract

There has been increasing interests in lithium microbatteries with the rapid development of semiconductor technology and micro-electro-mechanical systems (MEMS). In this work, lithium manganese oxide, which is more stable and less toxic than other oxides such as lithium nickel oxides and lithium cobalt oxides, was deposited using rf magnetron sputter, and the effect of thermal treatment on its microstructure, surface morphology, and electrode characteristics was investigated. Post-thermal treatments were done to gain proper crystallization of spinel lithium manganese oxide. The crystal structure of the samples vas characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. For electrochemical tests, half cells were made with the lithium manganese oxide as the cathode, the lithium metal as the allude, and a l-M solution of LiPF6 in EC-DMC (1:1) as the electrolyte. Charge-discharge experiments were performed with various cut-off voltages and current densities.