Microstructural characteristics and the charge-discharge characteristics of Sn-Cu thin film materials

Abstract

In this study, radio frequency magnetron sputtering was used to prepare Cu6 Sn5 film anodes. The effects of the thickness of the film and its index of crystallinity (IOC) on the charge-discharge capacity characteristics are discussed. Increasing the thickness of the film anode from 500 to 1500 nm, not only raised the IOC, but also improved the migration of lithium ions and electrons because of the lower resistivity. So, the cyclability of the as-adopted film was enhanced with increasing the film thickness. After recrystallization, the IOC rose and the resistivity fell. However, cracks on the film induced by thermal strain increased the area of the passive film, resulting in reduced cyclability. Also, prolonging the duration of sputtering (5000 nm) led to a deterioration in the charge-discharge capacity. © 2009 The Japan Institute of Metals.