Preparation of nanosheets of Ni5P2@Ni9S8/CoS1.097 heterostructure for aqueous asymmetric supercapacitors with high electrochemical performance

In recent years, transition metal sulfides, especially nickel-cobalt sulfide materials play a crucial role for supercapacitor applications. In this work, the Ni5P2@Ni9S8/CoS1.097 (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 ac-tivated 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. (c) 2022 Published by Elsevier B.V.

Automated summary

Transition metal sulfides, especially nickel-cobalt sulfides, have become crucial materials in supercapacitor applications in recent years. In this work, a core-shell material, Ni5P2@Ni9S8/CoS1.097 (Ni-P@NCS), was synthesized and used as an electrode material to improve the electrochemical performance.