A graphene wrapped hair-derived carbon/sulfur composite for lithium-sulfur batteries

A hair-derived carbon/sulfur composite was prepared via a facile melt-diffusion strategy and successively wrapped with reduced graphene oxide (rGO) sheets by electrostatic self-assembly. This composite was used as the sulfur electrode for lithium-sulfur (Li-S) batteries, exhibiting high capacity, good rate capability, and excellent cyclability. The electrode containing 69.0% (by weight, wt%) sulfur delivered an initial discharge capacity of 1113.2 mA h g(-1) and 989.2 mA h g(-1) after 300 cycles at a current density of 0.2 C with an average coulombic efficiency of 99.3%. Its capacity retention at 2 C was measured to be 62% with respect to the capacity achieved at 0.2 C. The high-performance of this electrode in Li-S batteries can be attributed to the porous carbon infrastructure, inherent nitrogen-doping and graphene protection. Taking into account the low-cost of raw materials and easy scalable processes, this work features a promising approach to prepare sulfur/carbon composites for high-performance Li-S batteries.