CoNi-ZIF-derived NiCo2Se4-NC promotes polysulfide adsorption and reaction kinetics in high-performance lithium-sulfur batteries

In this study, NiCo2Se4-NC was synthesized by high-temperature carbonization of zeolitic imidazole skeleton (CoNi-ZIF) and solvothermal technique, and its polyhedral structure with prominent specific surface area and numerous pores effectively mitigated the effect of volume expansion. Similarly, the bimetallic Ni/Co synergy improves the adsorption of polysulfides by the cathode material, thus improving the electrochemical performance of the battery. Density function theory (DFT) and static adsorption experimental results indicate that NiCo2Se4-NC has excellent binding properties to polysulfides. NiCo2Se4-NC was tested electrochemically as the cathode material and had an excellent initial discharge capacity of 1393.7 mAhg−1 at 0.1 C. In addition, the initial discharging specific capacity was 841.6 mAhg−1 with a capacity retention of 79% at 450 cycles at 1 C current density, and the coulombic efficiency always ranged from 100% to 101.5%, indicating that NiCo2Se4-NC has good cycling stability and reversibility of the reaction.