Synergetic restriction to polysulfides by hollow FePO4 nanospheres wrapped by reduced graphene oxide for lithium–sulfur battery

Abstract

Lithium-sulfur battery has been considered as the prospective competitive candidate for energy storage device, because of its huge advantages in specific capacity and energy density. Nevertheless, the application of lithium-sulfur battery is impeded by intrinsic polysulfide shuttle effect and poor electric conductivity of sulfur. To overcome these obstacles, hollow FePO4 spheres wrapped by reduced graphene oxide (FePO4@rGO) as efficient sulfur host material is synthesized. The hollow FePO4 spheres with large inner space are in favors of sulfur loading and buffer the volume expansion between S and discharge products (Li2S/Li2S2) during cycling process. Meanwhile, the hollow and polar FePO4 spheres afford synergy of physical confinement and chemical interaction to restrict polysulfides shuttle effect. Furthermore, the wrinkled rGO tightly-wrapped on the surface of FePO4 offers an interconnected conductive network. Profit from these merits, the FePO4@rGO as sulfur host manifests an impressive cycle stability with a low capacity decay rate of 0.037% per cycle at 0.5 C upon 1000 cycles, suggesting its enormous potential for high-performance Li–S battery.