In-situ growth of cobalt oxide nanoflakes from cobalt nanosheet on nickel foam for battery-type supercapacitors with high specific capacity.

Ni foam supported Co 3 O 4 nanoflakes is prepared for battery-type supercapacitor application through a simple three-step route. In briefly, Co metals are first deposited on Ni foam with a nanosheet morphology. The CoC 2 O 4 protrudes out from the surface of Co through an in-situ reaction with H 2 C 2 O 4 to form dendritic-like nanowires morphology. Finally, Co 3 O 4 are obtained through thermal decomposition of the CoC 2 O 4 precursor and the dendritic-like nanowires morphology is melting and transforming into a nanoflakes morphology. The unique architectures morphology with porosity and interconnected channels has great advantages since it can effectively increases the contact surface area with electrolyte, which could significantly not only enhances surface area but also the ion/electron diffusion. Electrochemical tests show that Co 3 O 4 nanoflakes exhibit a high specific capacity up to 576.8 C g − 1 at a current density of 1 A g − 1 and remain 283.7 C g − 1 capacity at a high current density of 50 A g − 1 , as well as 82% capacitance retained after 5000 cycles. These above results demonstrate the great potential of Co 3 O 4 nanoflakes in the development of battery-type supercapacitors. [ABSTRACT FROM AUTHOR]