A High-Performance Polysulfide-Trapping Lithium Sulfur Battery Cathode: Cubic Co3O4 Catalyst within a Nitrogen-Doped Entangled Graphene Framework

Abstract

The cycling performance of lithium-sulfur (Li−S) batteries is hampered by polysulfide dissolution which impacts the overall performance of Li−S batteries. Here we report the synthesis and characterization of polysulfide trapping cathode material for Li−S batteries based on Co₃O₄ nanocubes supported within a nitrogen-doped entangled graphene (Co₃O₄/NEGF). The highly porous conductive graphene network is shown to facilitate fast electron transport and ion diffusion while the nitrogen dopants and polar Co₃O₄ offer both abundant active sites for polysulfide conversion while promoting intermediate polysulfide binding. The porous structure allows for high sulfur loading of 76.4 wt % (S@Co₃O₄/NEGF), while efficiently accommodating volumetric expansion during charge-discharge. The Co₃O₄/NEGF cathode composite exhibited a high specific capacity of 1143 mAh g⁻¹ at a current density of C/20 and maintained a 79 % reversible capacity after 200 cycles at C/5.