Ni3S2 Thin-Layer Nanosheets Coupled with Co9S8 Nanoparticles Anchored on 3D Cross-Linking Composite Structure CNT@MXene for High-Performance Asymmetric Supercapacitor

•The Ni/Co@C5M displays cross-linking structure with fast ions transport.•The Ni/Co@C5M shows the excellent specific capacitance of 1827.5 Fg−1 at 1 A g−1.•The assembled asymmetric supercapacitor has a superior energy density of 78.4 Wh kg−1 at 699.3 W kg−1.•The energy density is better than others related ASC devices reported in previous work.