Ultrathin sheets of MoS₂/g-C₃N₄ composite as a good hosting material of sulfur for lithium–sulfur batteries

An intrinsically polar molybdenum disulfide/graphitic carbon nitride porous nanosheets (MoS₂/g-C₃N₄) has been designed as the sulfur host to improve the performance of lithium-sulfur (Li–S) batteries. The strong chemical interaction of lithium polysulfides with MoS₂ and nitrogen rich g-C₃N₄ restrict the shuttling effect of polysulfides, showing stable cycling and excellent rate performance of Li–S batteries by delivering a specific capacity of 430mAh/g after 400 cycles at 8C rate with a low capacity-fading rate of 0.028% per cycle. For the cathode with high areal loading of 4.3 mg/cm², it gives a very good capacity retention with a decay rate of 0.070% per cycle after 500 cycles at 0.5C. The dramatic improvement in lithium-ion diffusion is responsible for the high rate capability. The cells also exhibit an effective suppression of self-discharge. They deliver a specific discharge capacity retention of 93.60% and maintain cycling stability for 500 cycles at 1C with 0.08% per cycle decay rate after 10 days of resting. The results demonstrate that integration of both physical entrapment and chemical interaction with polysulfides could be an effective strategy for developing high performance Li–S batteries.