Novel Design and Synthesis of Ni-Mo-Co Ternary Hydroxides Nanoflakes for Advanced Energy Storage Device Applications

Three-dimensional interconnected mesoporous nanoflakes of amorphous Ni-Mo-Co trimetallic hydroxides were successfully deposited on a Ni foam (NF) using a facile, environmentally friendly, and scalable electrochemical deposition method. The elemental composition of the nanoflakes, including Ni 2+ , Mo 6+ , and Co 2+ , was characterized by X-ray photoelectron spectroscopy (XPS), while the morphology and particle size of the synthesized nanomaterials were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The Ni-Mo-Co trimetallic hydroxides on NF were employed as binder-free electrodes for supercapacitors. The Ni-Mo-Co trimetallic hydroxides with a Ni/Mo/Co ratio of 1/1/0.4 exhibited outstanding long-term cyclability over 5000 cycles, with a high reversible specific capacitance of 2700 F g −1 and a high capacitance retention of 96.63% at 10 A g −1 . Furthermore, they demonstrated excellent rate performance, maintaining a capacitance of 2429 F g −1 at a current of 50 A g −1 , which corresponds to approximately 80% capacitance retention compared to the capacitance at 2 A g −1 . The superior performance of these Ni-Mo-Co trimetallic hydroxides can be attributed to their mesoporous hierarchical architecture, which provides large open spaces between the interconnected nanoflakes, numerous electroactive surface sites, facile electron transmission paths, and the synergistic effects of the trimetallic components. These findings demonstrate that Ni-Mo-Co trimetallic hydroxides are promising electrode materials, offering both high capacitance and long-term cyclability for supercapacitors.