Three-dimensional-networked NiCo₂S₄ nanosheet array/carbon cloth anodes for high-performance lithium-ion batteries

We present the design and synthesis of three-dimensional (3D)-networked NiCo₂S₄nanosheet arrays (NSAs) grown on carbon cloth along with their novel application as anodes in lithium-ion batteries. The relatively small (~60%) volumetric expansion of NiCo₂S₄ nanosheets during the lithiation process was confirmed by in situ transmission electron microscopy and is attributed to their mesoporous nature. The 3D network structure of NiCo₂S₄ nanosheets offers the additional advantages of large surface area, efficient electron and ion transport capability, easy access of electrolyte to the electrode surface, sufficient void space and mechanical robustness. The fabricated electrodes exhibited outstanding lithium-storage performance including high specific capacity, excellent cycling stability and high rate of performance. A reversible capacity of ~ 1275 mAh g^{- 1} was obtained at a current density of 1000 mA g ^{- 1}, and the devices retained ~ 1137 mAh g ^{- 1} after 100 cycles, which is the highest value reported to date for electrodes made of metal sulfide nanostructures or their composites. Our results suggest that 3D-networked NiCo₂S₄ NSA/carbon cloth composites are a promising material for electrodes in high-performance lithium-ion batteries.