Ultrafine Nano-Sulfur Particles Anchored on In-situ Exfoliated Graphene for Lithium-Sulfur Batteries
The development of lithium-sulfur is still impeded by two main obstacles, the dissolution of lithium polysulfides and the pristine insulation of sulfur. Here, high energy ball-milling with the assistance of dielectric barrier discharge plasma has been explored to synthesize ultrafine sulfur particles anchored on in-situ exfoliated graphene for Li-S batteries. The formed ultrafine sulfur particles ont only afford more sufficient electrical contact towards graphene support and alleviate volume expansion compared to bulk sulfur. On the other hand, with robust etching function of dielectric barrier discharge plasma, litthle oxygen-doping was observed in exfoliated few-layer graphene, offering sufficient capture sits towards lithium polysulfides. Ultrafine sulfur/graphene composite with little oxygen-doping exhibits a superior cycling performance and rate capability in contrast to the control samples without the exertion of dielectric barrier discharge plasma. Little capacity degradation rate of 0.07% per cycle was achieved at 0.5 C over 500cycles.