Heteroatom-Doping Modulates Metal-Support Interactions in Carbon-Supported Cobalt Catalysts to Accelerate Polysulfide Redox for Lithium–Sulfur Batteries

Abstract

High redox kinetic barriers and the severe shuttle effect of lithium polysulfides (LiPSs) are two primary challenges for the practical deployment of lithium-sulfur (Li–S) batteries. Herein, highly dispersed Co nanoparticles embedded into S, N co-doped hollow chained carbon sphere (Co@SNC) are well-designed and prepared and served as an effective host catalyst for Li–S batteries. Doped S-atoms can effectively modulate the electronic metal-support interaction between Co nanoparticles and carbon matrix, which induces charge redistribution and increased d-orbital energy levels. Co@SNC can provide strong chemical interaction with LiPSs and reduce the Li⁺ diffusion barrier, which can effectively anchor LiPSs and accelerate the LiPSs conversion kinetics. The hollow chain-like structure of Co@SNC also synergistically suppresses LiPSs shuttling and enables high sulfur loadings and rapid charge/mass transfer. These merit the Li–S batteries based on Co@SNC with high reversible capacity, impressive rate performance, and prolong cycling stability with a low capacity decay of 0.024% per cycle over 1700 cycles. Notably, the Co@SNC/S electrode still delivers a high initial capacity of 814.9 mAh g⁻¹ and superior cycling performance even at high sulfur loading and poor electrolytes.