Anchoring electron-delocalized CeO2 on porous carbon for expediting polysulfide kinetics toward high-loading Li–S batteries

Abstract

High-energy-density lithium sulfur batteries with high mass loading are restricted by the depressive electrochemical kinetics of polysulfide conversion. Herein, to enhance catalytic efficiency, abundant electron-delocalized CeO₂ nanoparticles are anchored on the surface of pollen-derived carbon (PC-CeO₂) via one-step carbonization, serving as a sulfur host. In this design, pollen-derived carbon (PC) with a porous structural network enhances the electrical conductivity of the sulfur cathode while alleviating volume expansion and maintaining the stability of the cathode. The strategic incorporation of electron-delocalized CeO₂ nanoparticles is beneficial for the adsorption and catalysis of polysulfides, limiting the shuttle effect of polysulfides and effectively facilitating the electrochemical conversion kinetics. As a result, the fabricated sulfur cathode (PC-CeO₂/S) exhibits excellent electrochemical stability with a decay rate per cycle of 0.054% after 1000 cycles at 1C and outstanding rate performance (703.3 mAh g⁻¹ at 3C). Furthermore, it achieves an impressive areal capacity of 5.64 mAh cm⁻² at 0.2C even with a high sulfur loading of 5.5 mg cm⁻², demonstrating its potential for practical, high-energy-density applications in lithium–sulfur batteries.