Formation of Hollow Co3O4 Nanoparticles on Nitrogen–doped Porous Carbons for Highly Capacitive Performance

Abstract

AbstractCo3O4 nanoparticles are incorporated into nitrogen‐doped porous carbons to investigate their potential as supercapacitors. The nano‐sized Co3O4 particles grow and their morphology becomes hollow on the carbon support, which is attributed to the atomic diffusion (the Kirkendall effect) during the annealing. The cobalt‐doped composites have high BET surface areas of about 3000 m2 g−1 and possess mesopore‐dominant structures caused by the hollow Co3O4 nanoparticles. As a result, the hollow Co3O4 in the composites simultaneously induces both enhanced pseudo‐capacitance and efficient pore structure for energy storage. The specific capacitance of the composites is as high as 300 F g−1 in an aqueous solution of 6 M KOH at 1 A g−1, and the material shows competitive specific capacitance of 210 F g−1 at 10 A g−1 for a high power density. The present study provides a unique insight into the synthesis of hollow nanoparticles on a porous substrate material for high‐performance supercapacitance.