Abstract
Well-aligned nickel oxide (NiO) nanosheets with the thickness of a few nanometers supported on a flexible substrate (Ni foam) have been fabricated by a hydrothermal approach together with a post-annealing treatment. The three-dimensional NiO nanosheets were further used as electrode materials to fabricate supercapacitors, with high specific capacitance of 943.5, 791.2, 613.5, 480, and 457.5 F g-1 at current densities of 5, 10, 15, 20, and 25 A g-1, respectively. The NiO nanosheets combined well with the substrate. When the electrode material was bended, it can still retain 91.1% of the initial capacitance after 1,200 charging/discharging cycles. Compared with Co3O4 and NiO nanostructures, the specific capacitance of NiO nanosheets is much better. These characteristics suggest that NiO nanosheet electrodes are promising for energy storage application with high power demands.
Highlights
Supercapacitors, called electrochemical capacitors, are the most promising energy storage and power output technologies for digital communication devices, hybrid electric vehicles, and other high-power energy sources, which are attributed to the advantages of high power density, short charging time, high cycle efficiency, and long cycle life [1,2,3,4,5,6]
Synthesis of nickel oxide (NiO) nanosheets on Ni foam The NiO nanosheets were synthesized by a simple hydrothermal method: First, the Ni foam substrate was immersed in a 3 M HCl solution to remove the possible oxide layer on the surface
Well-aligned NiO nanosheets are fabricated by a hydrothermal approach, and it is used as binder-free electrodes for supercapacitors
Summary
Supercapacitors, called electrochemical capacitors, are the most promising energy storage and power output technologies for digital communication devices, hybrid electric vehicles, and other high-power energy sources, which are attributed to the advantages of high power density, short charging time, high cycle efficiency, and long cycle life [1,2,3,4,5,6]. Due to the low energy density of current supercapacitor products, nowadays, developing novel electrode materials with enhanced energy density, while maintaining a high power density, good specific capacitance, and cycling stability for supercapacitors, has become a primary research focus. The practical applications of supercapacitors are largely hindered due to the lack of high-performance electrode materials at a reasonable cost [7,8,9]. A facile solution method is developed to grow NiO nanonsheets directly on Ni foam, which possess an enhanced electrochemical performance for supercapacitors. Our optimized supercapacitor shows a specific capacitance of 943.5 F g−1 at a current density of 5 A g−1. It can be concluded that vertical NiO nanosheets would be suited to the high-performance electrodes for supercapacitors
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call