Supercapacitor electrode with an ultrahigh Co3O4 loading for a high areal capacitance

•Supercapacitor electrode heavily loaded with active material suffers from low areal capacitances.•An electrode heavily loaded with mesoporous Co3O4 is prepared.•The Co3O4 electrode exhibits a superior areal capacitance and excellent long-term cyclability.

Supercapacitor electrodes heavily loaded with active material suffer from low areal capacitances because close-packed, thick films are often obtained with high mass loading. In this work, nanostructured, mesoporous Co3O4 was directly deposited on a free-standing carbon substrate and evaluated as a supercapacitor electrode. The mesoporous structure combined with a conductive carbon network maximizes the utilization of active material, resulting in a high areal capacitance in spite of the high Co3O4 loading.