Fig a shows the cyclic voltammogram

During anodic scan, two peaks centered at 0.21 V and 0.67 V were observed. On subsequent cycling, two cathodic and anodic peaks were observed corresponding to the two step lithiation and delithiation process. The cathodic peak at 0.25 V was due to the lithiation of MgS and that observed at 0.005 V was due to the alloying of Li with Mg that is formed during the reduction of MgS [32], [33] and [34].