Use of CoNi-ZIF-derived bimetallic-doped nitrogen-rich porous carbon (CoNi-NC) composite Bi₂S₃ in lithium-sulfur batteries

Lithium-sulfur batteries have not been widely commercialized due to issues with poor conductivity of the active material and the shuttle effect, both of which are effectively addressed in this study. The porous carbon CoNi-NC, derived from high-temperature carbonization of the cobalt–nickel metal–organic framework CoNi-ZIF, was utilized as the carbon substrate. It exhibits excellent specific surface area and a well-developed pore structure, thereby optimizing the conductivity and sulfur-loading capacity of the material. The incorporation of polar Bi₂S₃ effectively adsorbs polysulfides, retards the shuttle effect, and enhances the reaction kinetics of lithium-sulfur batteries. Electrochemical tests revealed that the CoNi-NC@Bi₂S₃ electrode achieved a specific discharge capacity of 1107 mAh/g at 0.1 C rate, demonstrating excellent rate capability. Moreover, the cathode material maintained a specific discharge capacity of 796.5 mAh/g after 200 cycles at 0.2 C, indicating robust cycling stability.