Glycine-assisted hydrothermal synthesis of nanostructured Co x Ni1−x –Al layered triple hydroxides as electrode materials for high-performance supercapacitors

Nanostructured Co _x Ni_1−x –Al layered triple hydroxides (Co _x Ni_1−x –Al LTHs) have been successfully synthesized by a facile hydrothermal method using glycine as chelating agent. The samples were characterized by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The morphologies of Co _x Ni_1−x –Al LTHs varied with the Co content and its effect on the electrochemical behavior was studied by cyclic voltammetry and galvanostatic charge–discharge techniques. Electrochemical data demonstrated that the Co _x Ni_1−x –Al LTHs with Co/Ni molar ratio of 3:2 owned the best performance and delivered a maximum specific capacitance of 1,375 F g⁻¹ at a current density of 0.5 A g⁻¹ and a good high-rate capability. The capacitance retained 93.3% of the initial value after 1,000 continuous charge–discharge cycles at a current density of 2 A g⁻¹.