Mo2C/Co@NC heterointerface engineering toward polysulfide regulation in LiS batteries

Abstract

LiS battery suffers from polysulfides' shuttle effect and unsatisfactory redox kinetics. To tackle these issues, we design a multi-functional interlayer based on heterogeneous Mo₂C/Co confided by N-doped porous carbon (Mo₂C/Co@NC) via one-step controlled pyrolysis of Co²⁺/MoO₄²⁻/2-methylimidazole. The heterogeneous Mo₂C/Co as active centers effectively immobilizes polysulfides and accelerates their redox transformation kinetics. Moreover, the hierarchical porous NC matrix guarantees rapid electron/ion transport. Acting as an interlayer, the electrochemical evaluation demonstrates desirable performance. Specifically, a high initial discharge capacity of 874.0 mAh g⁻¹ is achieved at 3C, which retains 373.3 mAh g⁻¹ after 1000 cycles (capacity fading rate: 0.057 %/cycle), significantly outperforming battery without interlayer (0.082 %). This work demonstrates an effective heterointerface engineering strategy for the development of LiS battery practical application.