Graphene oxide/Cu(OH)2 composites as efficient multifunctional hosts for lithium-sulfur batteries

Abstract

Lithium-sulfur batteries are advanced energy storage system with high theoretical specific capacity and low cost but suffer from poor cyclic performance. To overcome the shortcomings, this study synthesized graphene oxide (GO)/Cu(OH)2 composites using the modified Hummers method and electrostatic self-assembly process. The sulfur was anchored in the GO/Cu(OH)2 composites using the melting method. The oxygen-containing function groups of GO are helpful for achieving good ion/electron accessibility, and the interlayers of GO have many active sites for polysulfide conversion. The polar hydrophilic hydroxyl group of Cu(OH)2 particles have strong chemisorption for polysulfides during the electrochemical process. Therefore, the synergistic effect of GO and Cu(OH)2 in the composites as sulfur hosts can inhibit the dissolution and shuttling of polysulfides. The lithium-sulfur batteries with GO/Cu(OH)2 composites as hosts have high capacity of 1427 mAh g−1 at 0.1 C, 1222 mAh g−1 at 0.5 C, and excellent cyclic performance for 250 cycles with a retained capacity of 929 mAh g−1 (0.5 C).