Infixing NiS₂ nanospheres into a three‐dimensional rGO/CNTs‐Li carbon composite as superior electrocatalyst for high‐performance Li−S batteries

Abstract A novel flexible three‐dimensional (3D) architecture of lithiated carbon nanotubes (CNTs‐Li) interlacing reduced graphene oxide (rGO) loaded with NiS₂ (denoted as NiS₂@rGO/CNTs‐Li) was rationally designed and implemented as interlayer with dual functions to suppress lithium polysulfides (LiPSs) shuttle and enhance redox kinetics for high‐performance Li−S batteries. In our design, the introduced rGO and CNTs‐Li serve as the conductive skeleton for facilitating the fast electron/ion transfer, while the infixing NiS₂ catalyst could synchronously entrap the soluble LiPSs and speed up their interconversion. The chemical interaction between NiS₂ and LiPSs and the redox kinetics were probed by density functional theory (DFT) calculations and electrochemical measurements, respectively. Benefiting from the synergistic effect of 3D conductive skeleton and polar NiS₂ catalyst, the cell with the NiS₂@rGO/CNTs‐Li modified separator exhibits a high initial capacity of 1515 mA h g⁻¹ at 0.2 C and an excellent long‐term cycling stability up to 600 cycles with a low decay rate of 0.071% at 2.0 C.