Cobalt-embedded 3D conductive honeycomb architecture to enable high-sulphur-loading Li-S batteries under lean electrolyte conditions

High sulphur loading and lean electrolyte conditions are important to achieve the high theoretical energy density of lithium-sulphur (Li-S) batteries. However, serious problems such as low sulphur utilization and fast capacity fade are typically experienced under low electrolyte/sulphur (E/S) ratios and high sulphur loading conditions. To address these issues, a cobalt-containing three-dimensional conductive honeycomb (Co@N-HPC) is proposed in this work as a material for sulphur cathodes. The good electrical conductivity and high density of catalytic sites of (Co@N-HPC) allow fast redox kinetics of lithium polysulfide (LiPS) in high-sulphur-loading electrodes. In addition, the hierarchical structure and good wettability by the electrolyte of Co@N-HPC facilitates electrolyte penetration and LiPS conversion, leading to a high utilization of sulphur under lean electrolyte conditions. Therefore, at a current density of 0.2 C, a volumetric capacity of 1,410 mAh·cm⁻³ was attained with a sulphur loading of 5.1 mg·cm⁻² and an E/S ratio of 5 µL·mg⁻¹. This work provides ideas for the development of lean electrolyte Li-S batteries with a high sulphur loading.