Spherical NiS2/Ni17S18–C accelerates ion transport and enhances kinetics for lithium-sulfur battery host material

Transition metal sulfides exhibit notable catalytic activity and possess a high theoretical specific capacity as host materials in lithium-sulfur batteries. However, their restricted conductivity and sluggish Li⁺ transport hinder their broader application. In this research, we developed a Ni-based metal-organic framework (Ni-MOF) using nitrogen-containing benzimidazole and coupled it with a highly conductive carbon nanotube (CNT) to form Ni_xS_y (NiS₂–Ni₁₇S₁₈)–C/CNT. The N-doped carbon skeleton derived from the MOF enhances the adsorption and chemical anchoring of polysulfides, while the even distribution of NiS₂ and Ni₁₇S₁₈ enhances the redox reaction kinetics. Additionally, the conductive CNT networks aid in rapid electron transport, resulting in improved sulfur utilization. Consequently, the Ni_xS_y-C/CNT@S electrode demonstrates an impressive initial specific capacity of 1468 mAh g⁻¹ at 0.2C and maintains 904.4 mAh g⁻¹ after 200 cycles. Moreover, Ni_xS_y-C/CNT@S displays exceptional cycle stability, with a capacity retention of 76.20 % and a decay rate of only 0.05 % per cycle after 500 cycles at 0.5C. This study paves the way for the development and synthesis of cathode materials with outstanding electrochemical performance in LSBs.