Using ethylenediamine to prepare three dimensional nitrogen-doped graphene aerogel/sulfur composite for lithium-sulfur batteries

Three-dimensional nitrogen-doped graphene aerogel/sulfur (NGA/S) composites are studied for use as cathode materials in Li-S batteries. The NGA/S composites are fabricated using ethylenediamine (EDA) as a nitrogen source and 3D graphene structural modifier through a combination of one-pot hydrothermal and heat melt diffusion methods. The as-prepared NGA/S composites present a porous 3D interconnected network structure with a high sulfur loading of 77.3 wt%. The electrode with NGA/S as cathode delivers a high initial discharge capacity of 1258 mAh g(-1) at a current rate of 0.1 C and maintains a stable capacity of 1077 mAh g(-1) after 75 cycles. This high battery capacity and good cycle stability is primarily attributed to the flexible porous 3D structure and N-doping in graphene for this NGA/S structural design which can provide higher sulfur loading, faster charge transfer pathway and better immobilization of lithium polysulfides. The present study demonstrates that the 3D NGA/S composite is a promising material for application as the cathode in Li-S batteries.