Effect of nanosized Mg0.8Cu0.2O on electrochemical properties of Li/S rechargeable batteries

Nanosized Mg0.8Cu0.2O powders were prepared by sol–gel method. In order to improve the electrochemical performances of Li/S rechargeable batteries, Mg0.8Cu0.2O was used as an additive for crystalline vanadium pentoxide (c-V2O5)/S composite cathode. The composite electrodes with and without additive were characterized by scanning electron microscopy, galvanostatic charge–discharge, rate capability and cycle performance. The results showed that not only the cycle life and discharge capacity were improved, but also the rate capability was improved after the addition of Mg0.8Cu0.2O. The improvements of electrochemical performances were due to the adsorbing effect on polysulfide of Mg0.8Cu0.2O. Furthermore, the additive also had catalytic effect on promoting redox reaction of the Li/S batteries.