Enhanced Adsorption and Conversion of Polysulfides by ZIF-67-Based Co3O4/TiO2 Heterostructure and Attached Polypyrrole 3D Conductive Network for Lithium-Sulfur Batteries with Stable and Extended Cycling

Lithium-sulfur (Li-S) batteries are favored as ideal batteries for next-generation electrical stored energy systems owing to their high theoretical energy diversity and low operating costs. Therefore, the development of Li-S batteries with excellent rate capability and stable cycling is still a challenge. In this article, the electrochemical performance of lithium-sulfur batteries with high capacity and long cycle stability is achieved through dual physical and chemical adsorption effects using polypyrrole (PPy) attached to Co3O4/TiO2 heterojunction structures based on metal-organic frameworks (MOFs) backbone materials. Co3O4/TiO2 polyhedra form a built-in electric field, which is also a good adsorbent for polysulfides PPy nanotubes have a vacant structure, thus minimizing the volume expansion during deformation and maintaining the stability of the structure. The reversible specific capacities of lithium-sulfur batteries prepared based on Co3O4/TiO2/PPy electrodes are 1095 and 739.4 mAh g(-1) at 0.1 C and 1 C multiplicity, respectively, and the capacity retention rate is 77.84% after 500 cycles at 1 C multiplicity. The structural design of the S@Co3O4/TiO2/PPy anode demonstrates an excellent ability to limit LiPS and has great potential to provide a promising avenue for the practical application of lithium-sulfur batteries.