In recent years, transition metal sulfides, especially nickel-cobalt sulfide materials play a crucial role for supercapacitor applications. In this work, the Ni 5 P 2 @Ni 9 S 8 /CoS 1.097 (Ni-P@NCS) core-shell material has been synthesized by simply phosphating the nickel mesh and subsequent electrodeposition of NCS to obtain a nanosheet heterostructure on nickel foam. The Ni-P@NCS composite material has a higher gravimetric capacitance of 2445.7 F g−1 than pure Ni-P of 1116.6 F g−1 and NCS materials of 1104.3 F g−1 at 1 A g−1. At the same time, Ni-P@NCS electrode yields excellent cycling stability (91.4% capacitance retention after 5000 charge–discharge cycles). An asymmetric supercapacitor (ASC) device assembled from Ni-P@NCS and activated carbon electrodes can deliver a highest energy/power density of 42.8 Wh kg−1/799.8 W kg−1, with 94.3% capacitance retention after 10,000 cycles at 5 A g−1. The improvement of electrochemical performance makes it possible to use it as an electrode material. • The Ni 5 P 2 @Ni 9 S 8 /CoS 1.097 electrode has high specific capacitance, working potential window. • The Ni 5 P 2 @Ni 9 S 8 /CoS 1.097 composite material has a higher gravimetric capacitance of 2445.7 F g-1. • The potential window of Ni 5 P 2 @Ni 9 S 8 /CoS 1.097 //AC is 0–1.6 V and the energy density is 42.8 Wh Kg-1. [ABSTRACT FROM AUTHOR]