Effect of Si addition to thin-film SnO2 microbattery anodes on cycling performance

Thin-film SnO2 and Si-doped SnO2 microbattery anodes are deposited on a Mo/Si substrate by e-beam evaporator at room temperature. The deposited film are characterized by energy dispersion X-ray spectroscopy (EDS), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Constant-current galvanostatic charge–discharge tests of half cells are performed. Both the SnO2 film consist of short-range ordered small grains (nano-scale) and exhibit good ability to and extract Li+ ions. Electrochemical cycling performance is dependent on the cut-off voltage. Tin oxide film anodes which are cycled in the voltage range 0.1–0.8 V show the highest reversible capacity (302 μA h/cm2 μm for Si-doped film; 200 μA h/cm2 μm for pure SnO2 film) and the longest cycle-life. Its a papers that Si plays an important role as a glass former element in the Li---Si---O network by suppressing the growth of Sn grains, reducing the surface roughness, and enhancing film adhesion. Thus, Si-doped films are strong candidates for microbattery anodes with improved electrochemical cycling performance.