Ultrafine nano-sulfur particles anchored on in situ exfoliated graphene for lithium–sulfur batteries†
The development of lithium–sulfur is 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 was used in synthesis of ultrafine sulfur particles anchored on in situ exfoliated graphene for Li–S batteries. The ultrafine sulfur particles formed not only afford more sufficient electrical contact towards graphene support, but also alleviate volume expansion compared with bulk sulfur. On the other hand, with robust etching function of dielectric barrier discharge plasma, little oxygen-doping was observed in exfoliated few-layer graphene, offering sufficient capture sites towards lithium polysulfides. The ultrafine sulfur/graphene composite with little oxygen-doping exhibits 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 0.5C over 500 cycles.