Dual protection of sulfur by interconnected porous carbon nanorods and graphene sheets for lithium-sulfur batteries

A low-cost carbon/sulfur material has been prepared using interconnected porous carbon nanorods (PCNRs) as the framework, and self-assembled graphene sheets (GS) as the coating layer. This GS@PCNRs/S sulfur cathode exhibits excellent rate capability and cycle stability. It delivers a maximum discharge capacity of 549.9 mAh g(-1) at 1 C and keeps superior cyclability over 500 cycles with an average capacity fading rate of only 0.083% per cycle. The improved electrochemical performance is primarily attributed to the wrapped, internally porous architecture of GS@PCNRs/S, which not only can offer an excellent transport of lithium ions and electrons within the electrodes, but also can inhibit polysulfide diffusion by the external chemical and physical barrier of graphene sheets. (C) 2015 Elsevier B.V. All rights reserved.