A graphene-oxide-based thin coating on the separator: an efficient barrier towards high-stable lithium–sulfur batteries

The electrochemical performance of lithium–sulfur (Li–S) batteries can be significantly improved by simply coating a thin barrier layer on the separator. The spray-coating of a mixture of graphene oxides (GO) and oxidized carbon nanotubes (o-CNT) can achieve a barrier coating of only 0.3 mg cm−2, which is much less than conventional interlayers and has no negative impact on the energy density but significantly enhances the electrochemical performances of the whole battery device. Due to the binding forces induced by functional groups on GO and the interconnected nanoscale channels provided by o-CNT, the thus fabricated Li–S batteries show dramatically improved specific discharge capacities of up to 750 mAh g−1 at 1 C even after 100 cycles, more than twice those of batteries without barrier coatings.