Fabrication of Amorphous Mesoporous Ni(OH) 2 Hollow Spheres with Waxberry‐Like Morphology for Supercapacitor Electrodes

The amorphous mesoporous Ni(OH) 2 hollow spheres (Ni(OH) 2 ‐HSs) with waxberry‐like morphology were fabricated by using a facile hydrothermal method with poly(styrene‐acrylic acid) spheres as the template, followed by extraction of the template. In the hydrothermal process, Ni(NO 3 ) 2 ⋅6H 2 O was employed as the precursor of Ni(OH) 2 . SEM, TEM, XPS, XRD, and N 2 adsorption‐desorption isotherm techniques were used to characterize the structure and morphology of Ni(OH) 2 ‐HSs. The obtained Ni(OH) 2 ‐HSs have a uniform morphology with an average diameter of 300 nm and shell thickness of about 25 nm. The mesoporous shells of the Ni(OH) 2 ‐HSs are composed of amorphous Ni(OH) 2 particles. When used as an electrode, the as‐prepared Ni(OH) 2 ‐HSs exhibit pseudocapacitive behavior with a high specific capacitance of 2559 F g −1 at a scan rate of 1 mV s −1 and a good capacitance retention of 91.8% after 1000 cycles at a current density of 5 A g −1 . These results suggest promising applications of the waxberry‐like amorphous Ni(OH) 2 hollow spheres in electrode materials for supercapacitors.