Uniform P doped Co-Ni-S nanostructures for asymmetric supercapacitors with ultra-high energy densities

Uniform P doped Co-Ni-S nanosheet arrays were directly grown on Ni foams by an efficient and cost-effective process. The binder-free electrode of P doped Co-Ni-S nanosheet arrays possesses an ultra-high specific capacitance of similar to 3677 F g(-1) at 1 A g(-1) with an excellent rate capability (similar to 63% capacitance retention at 20 A g(-1)) and considerable cycling performance (similar to 84% capacitance retention after 10 000 cycles). Correspondingly, the asymmetric supercapacitors assembled with P doped Co-Ni-S as the positive electrode and AC as the negative electrode display an ultra-high energy density of similar to 68.7 W h kg(-1) at a power density of similar to 0.8 kW kg(-1). In view of these features, this work provides a simple and scalable strategy for designing electrodes and devices with superior electrochemical performance in next generation energy storage applications.