Optimizing hybrid supercapacitor performance through synergistic integration of metal–organic frameworks and metal oxides

Abstract

Metal–organic frameworks (MOFs) offer significant advantages for energy storage, including high surface area, customizable porosity, and abundant active sites. We utilized these properties to synthesize a novel barium-MOF and neodymium oxide composite (Ba-MOF/Nd₂O₃) as an electrode material for hybrid supercapacitors. Incorporating Nd₂O₃—a lanthanide-series rare-earth metal oxide—enhances the composite's electrochemical properties, particularly in terms of specific capacity, energy density, power density, and cyclic stability. In a half-cell setup, the composite provided a remarkable specific capacity of 718 C g⁻¹ at the lowest current density (1.9 A g⁻¹). For further investigation, a real device was functionalized, which provided better energy density of 96 Wh kg⁻¹ with a maximum power density of 9350 W kg⁻¹. The device exhibited a rate capability of 96% and capacity retention of 92%, even after the 5000 charge–discharge process. Furthermore, semi-empirical models were employed to assess the capacitive and diffusive contributions.