One-step electrodeposition fabrication of iron cobalt sulfide nanosheet arrays on Ni foam for high-performance asymmetric supercapacitors

Herein, a non-polluting and simple electrodeposition strategy is presented by us for fabricating ternary iron cobalt transition metal sulfide (FeCoS) on Ni foam with nanosheet arrays, which are used as cathode materials for asymmetric supercapacitors. The FeCoS-15 nanosheet arrays reveal an admirable specific capacitance of 3741.03 F g−1 when the current density is 1 A g−1 and also exhibit a fantastic cycling performance with 92.84% capacitance retention at 20 A g−1 up to 10,000 cycles. Furthermore, the asymmetric supercapacitors using the FeCoS-15 nanosheet arrays as the positive electrode and the activated carbon (AC) as the negative electrodes demonstrate remarkable electrochemical performance. Our device exhibits an energy density of 54.08 Wh kg−1 with the power density of 800 W kg−1, achieving an impressive cycling retention of 85.64% over 10,000 cycles. The excellent results show that FeCoS nanosheet array materials have a roomy application prospect for high-performance asymmetric supercapacitors.