In situ growth of hexagonal prism-like Ni(OH) 2 microrods on nickel foam as binder-free electrodes

In this paper, we report in situ growth of hexagonal prism-like Ni(OH) 2 microrods via one-step hydrothermal process, where nickel foam is directly oxidized in a high concentration hydrogen peroxide (H 2 O 2 ) solution without additional nickel sources, surfactant, or post-treatment. The nickel foam not only serves as a nickel source but also as 3D scaffold for Ni(OH) 2 growth to form binder-free electrodes. The in situ growth can ensure close contact between conductive Ni foam substrate and as-formed Ni(OH) 2 microrods, providing efficient electron collection paths and electrochemical stability. Mass loading of Ni(OH) 2 on nickel foam could be tailored by adjusting the concentration H 2 O 2 . Possible growth mechanism of hexagonal prism-like Ni(OH) 2 microrods is discussed to understand the morphologies under various H 2 O 2 concentrations. When works as a binder-free electrode, the Ni(OH) 2 -coated nickel foam exhibits a remarkable areal capacitance ~ 1.598 C cm −2 (560 C g −1 ) at a current density of 1 mA cm −2 , relatively high rate capability with 57.14% areal capacitance retained at 10 mA cm −2 , as well as better cycling stability with 72.9% areal capacitance remained after 3000 charge-discharge cycles. Such superior performance demonstrates that Ni(OH) 2 microrods in situ grown on metallic nickel foam substrate might be a potential electrode material for electrochemical capacitors.