NiS2 @MWCNTs as a promising anode material for lithium and sodium-ion batteries with superior cycling stability

The NiS2 @MWCNTs materials were synthesized using a straightforward hydrothermal one-step process, forming a 3D conductive network structure with stable and uniformly distributed nanosphere morphology. Electrochemical tests yielded a sodium storage capacity of 463.99 mAh g−1 after 400 cycles with 0.2 A g−1, and a coulomb efficiency of 83.3% at the first cycle, followed by excellent long-cycle stability with a capacity retention rate of 96.7% after 600 cycles at a high current of 1 A g−1. It's interesting to note that Na+ storage mechanism is provided by a pseudocapacitor. The 3D conductive network was credited with enhanced electrochemical performance and structural stability. The incorporation of multi-walled carbon nanotubes (MWCNTs) also improves the material conductivity and accelerated the ion transport efficiency, while modulation of the nano microsphere structure increases the reactive active sites and reduce the capacity loss. These findings highlight the great potential NiS2 @MWCNTs composites as a perfect anode material for sodium-ion batteries (SIBs), opening up new possibilities for sustainable energy storage solutions.