Multidimensional structure of CoNi(2)S(4) materials: structural regulation promoted electrochemical performance in a supercapacitor

Multidimensional architectures of CoNi(2)S(4) electrode materials are rationally designed by engineering the surface structure toward that of high-performance supercapacitors. The fabrication of a special morphology is highly dependent on the synergistic effect between the guidance of Co–Ni precursor arrays and a subsequent sulfidation process. The unparalleled CoNi(2)S(4) electrode materials (NS-3) deliver a significantly enhanced specific capacitance (3784.6 F g(−1) at 3 A g(−1)), accompanied by an extraordinary rate capability (2932.3 F g(−1) at 20 A g(−1)) and excellent cycling life. The outstanding supercapacitor performance stated above stems from the advantages of a multidimensional structure generated by crosslinking 2D microsheets/1D nanowires/2D ultrathin nanosheets; this structure supplies additional efficient active sites and a large contact area at the electrode–electrolyte interface, providing faster transport kinetics for electrons and ions. For practical applications, asymmetric devices based on an NS-3 positive electrode and active carbon negative electrode exhibit a high energy density of 38.5 W h kg(−1) accompanied by a power density of 374.9 W kg(−1) (22 W h kg(−1) at 7615.4 W kg(−1)). The above results indicate that the design of multidimensional Co–Ni–S materials is an effective strategy to achieve a high-performance supercapacitor.