Oxygen-Doped Porous Carbon Nanotubes Encapsulated Bismuth Oxide to Enhance the Performance of Lithium-Sulfur Battery

Lithium-sulfur batteries (LSBs) are greatly promising next-generation energy storage systems due to their high theoretical specific capacities and energy density. However, the dissolution of lithium polysulfides (LIPs) causees low capacity and short lifespan, impeding the practical application of LSBs. To address this challenge, the composites of oxygen-doped porous carbon nanotubes (CNTs) wrapped in Bi₂O₃ were synthesized by the calcinating method (CNTs@Bi₂O₃). The CNTs@Bi₂O₃ composites as absorbent immobilize LIPs via the physical limitations of porous CNTs and the chemical adsorption of Bi₂O₃ and carbon-oxygen polar bond. After loading sulfur, the CNTs@Bi₂O₃/S composites with the encapsulated structure can provide a large space to withstand the significant volume expansion during the electrochemical reaction process, ensuring the stability of the electrode structure. Thus, the batteries with CNTs@Bi₂O₃/S exhibit a high capacity (1232 mA h g⁻¹ at 0.1 C) and good cycle stability (639.1 mA h g⁻¹ after 150 cycles at 0.5 C). This work presents an innovative design suitable for the encapsulated structure of Bi₂O₃, serving as a valuable reference for the development of Bi₂O₃ in LSBs.