Facile synthesis of 3D gem shape Co3O4 with mesoporous structure as electrode for high-performance supercapacitors

In this work, a 3D gem shape Co3O4 nanomaterial using nickel foam (Ni foam) as substrate was synthesized as supercapacitor electrode. The morphology and structures of the Co3O4 were characterized by various test-methods including XRD, BET, FTIR, TG, SEM, TEM and XPS. The fabricated Co3O4 nanomaterial achieved an excellent capacitance of 1060.0 F g−1 at 1 A g−1 and a super-long cycling life with 99.6% retention rate after 5000 cycles at 8 A g−1. Moreover, the as-fabricated Co3O4//AC supercapacitor, with the as-prepared Co3O4 as positive electrode and the activated carbon as negative electrode, delivered a high energy density (44.99 Wh kg−1) at the power density of 0.2 kW kg−1. The superior performances were mainly due to the high specific surface area, the suitable pore structure, and the uniformed 3D “gem shape” morphology of the Co3O4 nanomaterials. This work is of great significance to the development of high-performance energy storage devices and even to other application fields such as photocatalysis and sensors.