FeS2 anchored to nitrogen-doped porous carbon nanosheets for lithium-sulfur batteries

Abstract

Lithium-sulfur batteries have attracted extensive attention as the next-generation rechargeable batteries because their theoretical energy density is much higher than that of traditional lithium-ion batteries. However, the poor cycling performance and rate capability caused by the polysulfide shuttle effect and sluggish reaction kinetics remain major obstacles to their practical application. This paper reports a nitrogen-doped continuous porous carbon nanosheets (N-PCNS) host anchored with FeS₂ nanoparticles (N-PCNS@FeS₂) prepared by a salt template method as an efficient catalytic matrix for the sulfur cathode. This host has strong adsorption ability for and promotes the catalytic conversion of polysulfides, hence inhibiting the shuttle of polysulfides. The sulfur cathode (N-PCNS@FeS₂/S) has a high specific capacity of 1074.6 mAh g⁻¹ in the first cycle and a decay rate of 0.34% per cycle in the 100 cycles at 0.2 C. It has better performance compared to the cathode only using N-PCNS host. At a high rate of 1 C for charge and discharge, the capacity in the first cycle is 782.5 mAh g⁻¹, and a capacity of 471.9 mAh g⁻¹ remains after 200 cycles, showing good cycling stability.