Nickel and Lanthanum Hydroxide Nanocomposites with Much Improved Electrochemical Performance for Supercapacitors

By developing a facile low temperature hydrothermal process, we demonstrate the direct growth of nickel and lanthanum hydroxide nanocomposites on Ni‐foam substrate. The hydroxide nanocomposites thus derived show much enhanced overall electrochemical capacitance and improved stability of the alpha nickel hydroxide phase in alkaline solution. By adjusting the initial molar ratio between nickel and lanthanum nitrates from 1:0 to 1:2, the electrochemical behavior, such as specific capacitance, shows a dramatic change, while the nickel hydroxide phase evolves from beta nickel hydroxides (1:0) to alpha nickel hydroxide (1:2). Lanthanum hydroxide is not expected to contribute to the pseudocapacitance as it only shows a capacitance of