Oxygen-doped NiCoP derived from Ni-MOFs for high performance asymmetric supercapacitor

Abstract Oxygen doping strategy is one of the most effective methods to improve the electrochemical properties of nickel–cobalt phosphide (NiCoP)-based capacitors by adjusting its inherent electronic structure. In this paper, O-doped NiCoP microspheres derived from porous nanostructured nickel metal–organic frameworks (Ni-MOFs) were constructed through solvothermal method followed by phosphorization treatment. The O-doping concentration has a siginificant influence on the rate performance and cycle stability. The optimized O-doped NiCoP electrode material shows a specific capacitance of 632.4 F-g −1 at 1 A-g −1 and a high retention rate of 56.9% at 20 A g −1 . The corresponding NiCoP-based asymmetric supercapacitor exhibits a high energy density of 30.1 Wh kg −1 when the power density is 800.9 W kg −1 , and can still maintain 82.1% of the initial capacity after 10 000 cycles at 5 A g −1 .