CoS2 nanoparticles anchored on N,B co-doped porous carbon for high-rate and long-life lithium–sulfur batteries
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Abstract
Lithium–sulfur (Li–S) batteries are regarded as one of the best choices for next-generation batteries due to their high energy density and low cost. However, there are three major challenges, namely the low electrical conductivity of sulfur and its products, the volume change during the electrochemical process, and the “shuttle effect” of lithium polysulfide. Carbon materials can alleviate the problems of electrical conductivity and volume change of sulfur. The shuttle of polysulfides can be further inhibited by doping heteroatoms or loading polar compounds. In this work, CoS2/porous boron–nitrogen co-doped carbon (CoS2/BNC) was prepared using a boron–nitrogen co-doped porous carbon precursor. The hollow structure can better adapt to the volume expansion during the sulfur reaction, and the chemisorption and redox kinetics of LiPSs are strengthened from multiple angles to inhibit the shuttle of LiPSs. The CoS2/BNC/S lithium–sulfur battery has a high initial discharge capacity of 1639.1 mAh g−1 under the condition of 0.1C. After 500 cycles at a current density of 2C, the capacity still remains at 752.7 mAh g−1, with a capacity decay of only 0.048% per cycle, and the coulombic efficiency can still be maintained at 97.8%, showing satisfactory electrochemical performance.
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