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

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 great 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 asymmetry supercapacitor shows 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 10000 cycles at 5 A·g-1.