Double carbon modified CoS2/NiS2 as anode material for efficient lithium storage performance

Abstract

To address the challenges associated with significant volume expansion and limited electronic conductivity of transition metal sulfides (TMSs) as anode materials in lithium-ion batteries. Nitrogen doped carbon (NC) and carbon nanotubes (CNTs) modified CoS2/NiS2 (Co-Ni-S/NC/CNTs) composites were prepared by a simple chemical precipitation method and sulfurization reaction. Co-Ni-S/NC/CNTs composites have special structure, utilizing NC as carrier and CNTs as cladding layer. When evaluated as anode materials for lithium-ion batteries, the initial discharge specific capacity of Co-Ni-S/NC/CNTs anode delivers 1518.8 mAh g−1 at 0.1 A g−1, and a high reversible capacity of 1137 mAh g−1 is kept after 100 cycles, which is higher than the discharge specific capacity (1117.1 mAh g−1) of the second cycle. At a current density of 0.5 A g−1, a capacity of 468 mAh g−1 is maintained after 300 cycles. The excellent cycling stability of the CoS2/NiS2 anode can be primarily attributed to that CNTs layer can enhance the conductivity of CoS2/NiS2, and the incorporation of NC can effectively improve the infiltration of electrolytes. Meanwhile, the synergistic action of CNTs and NC can mitigate the volume expansion during charging and discharging processes.