A one-step practical strategy to enhance overall supercapacitor performance

Abstract

We introduce a straightforward strategy to simultaneously improve the capacitance, rate capability, and cycle life of a supercapacitor by simply electrodepositing Ni-nanoparticles (Ni-NPs) on an as-prepared electrode. 3D-structured current collectors such as metal foams, metal meshes, and carbon meshes have been widely used in supercapacitors, secondary batteries, glucose sensors, etc. In particular, the 3D-metal foam readily improves device properties due to its unique 3D-nature and high surface area. However, there are practical constraints when applying 3D-current collectors to the industrial world, including high cost. Here, by simply electrodepositing Ni-NPs in a cost-efficient manner, a similar effect to that derived with the use of 3D-metal foam was realized. After deposition, Ni-NPs are preferentially located near the contact area between the active materials and a plate-type current collector, which allows for tight binding between the active materials and the current collector as well as facile charge transfer and high capacitance. The Ni-deposited Ni(OH)₂ electrode pasted on a plate metal substrate showed 350% increased capacitance (1264 F g⁻¹) and stability of 75% and 72% after 10 000 cycles and at a high current density of 20 A g⁻¹, respectively. Given the simplicity and cost-efficiency of this method, it can be readily applied to other energy storage devices with practical applications in the industrial world.