Promoting sulphur conversion chemistry with tri-modal porous N, O-codoped carbon for stable Li–S batteries

Abstract

Mitigating the shuttle effect and promoting the conversion kinetics of lithium polysulfides (LiPSs) are the key challenges to realizing practical Li–S batteries (LSBs). Herein, we show that N, O-codoped carbon with a tri-modal hierarchical porous structure derived from biomass can be used as a novel sulfur host for stable LSBs. The abundant heteroatoms of the biomass-derived carbon material significantly improve the adsorption and conversion of LiPSs through chemical interaction, leading to long-term stable cycling of LSBs. Additionally, the interconnected hierarchical porous structure provides efficient pathways for charge transport and alleviates the volume expansion of sulfur during the lithiation process. With respect to synergistic effects of the tri-modal porous structure and dual-heteroatom doped property, the biomass-derived carbon material delivers an initial capacity of 1123 mA h g⁻¹ at 0.2C, with a low capacity decay rate of 0.057% per cycle over 800 cycles at 1C. This work represents a sustainable approach for developing highly stable and long-lived LSBs.