Three-dimensional ultrathin Ni(OH)2 nanosheets grown on nickel foam for high-performance supercapacitors

•Ultrathin Ni(OH)2 nanosheets were grown on nickel foam at room temperature.•No additional nickel sources, templates, or surfactant were introduced.•Ni(OH)2 nanosheets displayed excellent pseudoactive performance.•The excellent performance is attributed to its unique nanostructures.•The 3D electrodes ideally suited for high-performance supercapacitor applications.

In this paper, we report the growth of ultrathin Ni(OH)2 nanosheets on nickel foam at room temperature via a cost-effective and simple process, oxidizing fresh nickel foam in a wet environment followed by a morphology transformation in a mixed alkaline and oxidative solution without the need for any additional nickel sources, templates, or surfactants. When tested as electrode for a supercapacitor, the Ni(OH)2 nanosheets grown on nickel foam displayed excellent performance, demonstrating specific capacitance of 2384.3 F g−1 at a charge and discharge current density of 1 A g−1 and 1288.1 F g−1 at 5 A g−1 with a good cycling ability (~75% of the initial specific capacitance remained after 3000 cycles). The excellent electrochemical performance is attributed to its unique nanostructures, which may facilitate rapid ion transport near electrode surfaces, while allowing facile redox reactions associated with charge storage by the nanosheets. The demonstrated high specific capacity and the remarkable rate performance of the Ni(OH)2 nanosheets, together with the flexibility of the nickel foam substrate, make the three-dimensional nanostructured electrodes ideally suited for low-cost, high-performance supercapacitor applications.

Graphical abstractA cost-effective and simple process was proposed to grow ultrathin Ni(OH)2 nanosheets directly from nickel foam at room temperature without adding any additional nickel sources, templates, or surfactant. Due to the high specific surface area and good contact with substrate, the Ni(OH)2 nanosheets have a specific capacitance of 1288.1 F g−1when tested as electrodes for a supercapacitor and maintained 75% of the initial capacity after 3000 cycles at a current density of 5 A g−1. The excellent electrochemical performance is attributed to its unique nanostructures, which may facilitate rapid ion transport near electrode surfaces. The demonstrated high specific capacity and the remarkable rate performance of the Ni(OH)2 nanosheets, together with the flexibility of the nickel foam substrate, make the three-dimensional nanostructured electrodes ideally suited for low-cost, high-performance supercapacitor applications.Figure optionsDownload full-size imageDownload as PowerPoint slide