Amplified Response of Nickel Oxide-Decorated Lanthanum Phosphate Composite as an Anode Material for Asymmetric Supercapacitors

The rapidly expanding global population and fast economic growth has led to a shortage of energy and electricity resources. The scarcity of effective energy storage technologies and environmentally friendly electrical power alternatives is one of the greatest concerns in the modern era. Asymmetric supercapacitors have garnered considerable attention due to their versatility in energy storage devices. However, they still require more effective electrode materials with superior electrochemical characteristics to improve their charge storage capacity, energy, and power parameters. To this end, in this work, nickel oxide (NiO), lanthanum phosphate (LaPO₄), and nickel oxide-decorated lanthanum phosphate (NiO/LaPO₄) nanosheets were synthesized by a facile hydrothermal method. The purity, crystallinity, and morphology of the materials were investigated using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS). The NiO-decorated LaPO₄ exhibited superior performance, providing higher specific capacity (Q_s) of 1054.4 C/g at 2.0 A/g. The developed electrode also demonstrated excellent electrical conductivity and stability (88% galvanostatic charge/discharge [GCD] retention for 1500 cycles) as determined by electrochemical impedance spectroscopy. The capacitive and diffusive contributions indicate that the fabricated material has an asymmetric storage nature. The results suggest that the prepared material could be used in asymmetric supercapacitor applications.