Built‐in Carbon Nanotube Network inside a Biomass‐Derived Hierarchically Porous Carbon to Enhance the Performance of the Sulfur Cathode in a Li‐S Battery

Abstract The practical application of lithium‐sulfur batteries is usually hindered by the unstable discharge intermediates and the low conductivity of the sulfur cathode. Herein, we propose to improve the performance of the sulfur cathode by introducing a built‐in carbon nanotube network inside a biomass‐derived hierarchically porous carbon for the subsequent sulfur loading. This balanced structural design of the carbon substrate enables effective trapping of active sulfur within the cathode and provides a highly efficient pathway for electron transmission, contributing to an increased conductivity and structural integrity of the cathode. By using a potentiostatic process at the end of charge, the reversibility of the electrode reaction of sulfur is improved. The sulfur cathode delivers an initial discharge capacity of 1739 mA h g⁻¹ and reaches a high initial Columbic efficiency of 87.6 %, and maintains its efficiency to >97.5 % from the 2nd cycle. It also shows admirable cycling and rate performance.