Investigation of Si–M (M = Mo, Ti, or V) negative electrodes fabricated using RF/DC magnetron sputtering for lithium ion batteries

Si and Si-based composite electrodes have been widely proposed as negative electrode materials in lithium ion batteries because Si has a large specific capacity of up to ten times that of graphite. A series of studies have been performed to investigate the reaction of Li with Si and SixM1 − x films, where M (M = Mo, Ti, or V) is a transition metal element which does not alloy with Li. The electrodes are deposited by an RF/DC magnetron co-sputtering system and are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface morphologies of the electrodes are observed using a field emission scanning electron microscopy (FESEM). The electrochemical properties of the electrodes were studied using cycling testing. Compared to Si electrodes, Si-based composite electrodes with different anode compositions have shown a great advantage in reversible reactions with Li. This composite system consequently improved the cycle life and coulombic efficiency of silicon-based anodes.