Uniform phosphorus doped CoWO4@NiWO4 nanocomposites for asymmetric supercapacitors

Transition metal oxides are widely used as the electrodes of supercapacitor attributing to their low cost and cycling stability. Herein, phosphorus doped NiWO4@CoWO4 nanocomposites are directly grown on nickel foams as supercapacitor electrodes. With the incorporating of P atom, many nanoparticles and O vacancies are formed on the surface of the optimized P-NiWO4@CoWO4. Accordingly, the P-NiWO4@CoWO4 exhibits a good cycling stability and high specific capacitance of 5.11 F cm(-2) at 1 mA cm(-2) (or a specific capacitance 1683.4 F g(-1) at 1 A g(-1)), nearly 2.5 times higher than that of NiWO4@CoWO4. P-NiWO4@CoWO4 electrode also shows great rate capability with 88% capacitance retention when the current density is increased tenfold. Moreover, an asymmetric supercapacitor (ASC) assembled with P-NiWO4@CoWO4 as the positive electrode and active carbon as the negative electrode with 6 M KOH as the electrolyte displays an excellent energy density of 0.15mWhcm(-2) at a power density of 0.79 mW cm(-2) (26.8 Wh kg(-1) at 824.6 W kg(-1)). (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Phosphorus-doped NiWO4@CoWO4 nanocomposites were successfully prepared as electrodes for supercapacitors, exhibiting excellent cycling stability, high specific capacitance, and great rate capability. Moreover, an asymmetric supercapacitor assembled with this electrode and activated carbon showed outstanding energy density and power density.