Preparation and Characterization of Thin Film Li[sub 4]Ti[sub 5]O[sub 12] Electrodes by Magnetron Sputtering

Abstract

This piper reports that spinel-phase Li4Ti5O 12 thin films were successfully grown by radio frequency (rf) magnetron sputtering on an Au/Ti/SiO2/Si substrate. In this process, the buffer layer of gold serves as a template for the texture growth of Li 4Ti5O12 film. The growth temperature affects the microstructure and electrochemical characteristics of the deposited films. In our study, the spinel phase of Li4Ti5O12 appears at deposition temperatures above 500°C. The redox peaks in the cyclic voltammetry of the Li/Li4Ti5O12 cell approach the typical value of 1.55 V as raising the deposition temperature. Moreover, the influences of the surface morphology of the film on the capacity were studied. They show that a columnar structure with high porosity was obtained in the film deposited above 650°C. The columnar grains with good crystallinity of the deposited Li4Ti5O12 enhance die capacity of the electrode. In this work, the capacity of 53 μAh/cm2 μm can be attained for the film with a thickness of 230 nm deposited at 700°C. This study sheds light on the realization of a solid-state thin film battery and provides a possible solution of electrical power for a mobile integrated circuit chip. © 2005 The Electrochemical Society. All rights reserved.