Dual taming of polysufides by phosphorus-doped carbon for improving electrochemical performances of lithium–sulfur battery

Abstract

Lithium–sulfur (Li–S) batteries are promising energy-storage technology, but a major technical issue is the shuttling of soluble polysulfides between electrodes, resulting in rapid capacity fading. In such case, phosphorus doped porous carbon spheres (P–C) material are designed and applied as both sulfur host material and separator modifier to mitigate the shuttling problem in Li–S batteries. The porous structure can physically intake polysulfides, and the same time, the phosphorus element can chemically interact with polysulfides. Based on the favourable combination of both physical adsorption and chemical anchoring, the assembled battery with as-prepared P–C materials acting as both sulfur host and separator modifier can achieve high utilization of active species and realize good cycling stability. Specifically, an initial capacity of 1430 mAh g−1 at 0.1 C and 650 mAh g−1 at 5 C is achieved, with outstanding cyclability and negligible capacity fading rate of 0.06% per cycle at 2 C even for 1000 cycles.