Effects of graphite on electrochemical performance of Sn/C composite thin film anodes

The composite thin films of tin with 0 wt.%, 3.2 wt.%, 6.0 wt.%, and 11.8 wt.% graphite on the Cu foil were fabricated by magnetron sputtering (MS). The surface morphology, the composition and the electrochemical performance of the composite films were characterized by scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and galvanostatic charge/discharge (GC) measurements. It is found that the capacity loss of tin can be significantly reduced by its composite with graphite, but its discharge capacity decreases with increasing the content of graphite. The composite with 6.0 wt.% graphite show its good discharge capacity and cyclic stability. Its initial discharge capacity is 750 mAh g−1 and it keeps 85% of its initial discharge capacity after 10 cycles, comparing to the 14% for the pure tin.