Hierarchical NiCo-LDHs/metal sulfides (V3S4, CuS, Mo2S3) heterostructures with improved electrochemical properties for asymmetric supercapacitors: A comparative study

A good approach to meet the high-performance requirements of supercapacitors is to introduce heterostructure to the transition metal sulfide electrodes. In this work, the hierarchical nanoflower-like NiCo-LDHs/V3S4 (NCs/V3S4) heterostructure is synthesized by the two-step hydrothermal process. The rational structure not only creates the sufficient active sites but also provides abundant ion/charge diffusion channels, facilitating the electrochemical reaction kinetics of the electrodes. NCs/V3S4 heterostructure, which advantages of the special structure and synergistic effect, exhibits a good rate capability and an exceptional specific capacitance of 1823.8 F g−1 at 1 A g−1 and 964.3 F g−1 at 30 A g−1. In addition, the assembled NCs/V3S4//AC asymmetric supercapacitors (ASCs) exhibit an exceptional energy density of 63.60 Wh kg−1 at a power density of 799.93 W kg−1 and good cycling stability with 99.04% capacitance retention after 6000 cycles, indicating that the strategy can improve ASCs stability and energy density. For comparison, NiCo-LDHs/Mo2S3//AC (NCs/Mo2S3//AC) and NiCo-LDHs/CuS//AC (NCs/CuS//AC) ASCs are assembled and the electrochemical performances of the three NCs/metal sulfides//AC ASCs are systematically investigated and compared. In conclusion, the distinctive structural design can successfully manage the interface charge states, ensuring the structural integrity of electrode materials and resulting in superior electrochemical performance.