A Facile Synthesis of Three Dimensional β-Ni(OH)2 Composed of Ultrathin Nanosheets for High Performance Pseudocapacitor

Hierarchical β-Ni(OH)2 nanostructures composed of ultrathin nanosheets were synthesized via a hydrolytic process of nickel chloride. The obtained samples were characterized by X-ray diffraction, thermal gravimetric, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectrometer. The corresponding results show that the Ni(OH)2 has a β-phase structure, and the hierarchical β-Ni(OH)2 nanostructures are made up of several cross-linked nanosheets, and the thickness of the nanosheets is only 9.3 nm. The ultrathin nanosheets provide a very short diffusion channel for ion migration, which is beneficial to improve the electrochemical activity of the sample. The ultrathin β-Ni(OH)2 nanosheets aggregates have a specific capacitance of 1727 F/g at a current density of 1 A/g. Increasing the current density to 20 A/g, the specific capacitance can still maintain at 1235 F/g. Importantly, after 1000 charge–discharge cycles, the results show that the loss of the specific capacitance is only 1.6% at 1 A/g, and the loss is 27.9% at 20 A/g. The excellent performances of β-Ni(OH)2 nanostructures used as pseudocapacitors reveal the great potential of ultrathin nanosheets materials in energy storage.