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 Co 3 O 4 /TiO 2 heterojunction structures based on metal–organic frameworks (MOFs) backbone materials. Co 3 O 4 /TiO 2 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 Co 3 O 4 /TiO 2 /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@Co 3 O 4 /TiO 2 /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.