Amorphous Cobalt Phosphate Porous Braced-Frame Nanocubes as Highly Efficient Supercapacitor Electrodes

Abstract

It is extremely urgent to develop novel electrode materials with large capacity, high charge–discharge speed, and cycle stability for the particular application of supercapacitors in electric vehicles. Cobalt-based phosphate materials have attracted increasing attention due to their outstanding properties. Herein, cobalt phosphate with a braced-frame nanocube morphology consisting of amorphous nanoparticles is synthesized through a one-step ion-exchange method using Prussian Blue Analog Co3[Co(CN)6]2 nanocubes as precursors. Benefiting from the special nanostructure, this material shows a specific capacitance of up to 539.2 F g–1 at 1 A g–1, a capacitance retention of 92% even at 8 A g–1, and remarkable cycle stability characteristics, with a capacity preservation of 89.1% after 3000 charge–discharge cycles at 2 A g–1. The kinetic mechanism demonstrates that the diffusion-controlled procedure has made a great contribution to the large capacitance. This study will be helpful for the development of new electrode materials for supercapacitors.