NiS2 nanospheres coated by nitrogen-doped carbon for enhanced sodium storage performance

Nickel disulfide is used as anode material for sodium-ion batteries, with low cost, abundant reserves, and a wide variety of theoretical specific capacities as high as 870 mAh g-1. However, large volume expansion and low ionic conductivity during Na+ intercalation and deintercalation lead to poor electrochemical perfor-mance. This work has synthesized carbon layer-coated and N-doped NiS2 nanospheres through PVP-assisted hydrothermal and subsequent annealing processes, reducing volume expansion and improving electrical conductivity and Na+ storage activity, increasing ion diffusion kinetics during electrochemical charge -dis-charge in excellent specific capacity and cycle stability. When evaluated as a negative electrode for Sodium -ion batteries (SIBs), it exhibits excellent specific capacity (554.3 mAh g-1 at 0.2 A g-1, first-cycle coulombic efficiency of 92.3 %), and excellent long-cycle stability (436.3 mAh g-1 at 1 A g-1 for 800 cycles), demon-strating the potential of NiS2@NC as an ideal anode material for SIBs.(c) 2022 Elsevier B.V. All rights reserved.