MOF-Integrated LTH Heterostructures with Negative Potential Shift for Supercapacitor Applications

Abstract

Supercapacitors (SCs) differ significantly from batteries due to their superior electrochemical performance. Metal–organic framework (MOF)-based electrodes exhibit promise for use in energy storage systems, and their possible implementations have been reported. In this research work, we employ a two-step hydro/co-precipitation method to synthesize different types of metal oxide-based nanocomposite electrode materials, including C-LH, FC-LDH, and CFC-LTH. Additionally, CFC-LTH@MOF is prepared, and its electrochemical activity is studied. Trimetallic (Co, Fe, and Ce) CFC-LTH@MOF positive electrodes are prepared on nickel foam, which is utilized as a substrate due to its high conductivity, by the hydrothermal synthesis method. Furthermore, the synthesis parameters were optimized to achieve the desired hierarchical morphology, thereby enhancing the electrochemical performance of CFC-LTH@MOF composites. The CFC-LTH@MOF electrode revealed a high areal/specific capacitance of 1.76 μAh cm²/2120.8 F g^–1 at a current density of 4 mA/cm², which was about 1.4 times higher than that of CFC-LTH (1.47 μAh cm²/2008 F g^–1), followed by FC-LDH (1.2 μAh cm²/1175.2 F g^–1) and C-LH (0.7 μAh cm²/887.2 F g^–1). Additionally, their structural, spectral, morphological, and crystalline properties, as well as their chemical states and surface features, were studied through appropriate characterization techniques. An asymmetric hybrid supercapacitor (HSC) device was successfully fabricated, and its electrochemical performance was evaluated through cyclic voltammetry (CV) and GCD analyses within a potential window of 1.6 V. The as-fabricated assembled coin cell HSC exhibits exceptional electrochemical characteristics, including outstanding cycling stability (10k cycles) and increased rate capability (96.5%). The obtained results demonstrate the improved electrochemical performance of the prepared nanocomposite electrode material, CFC-LTH@MOF-based HSCs which have high energy densities and are suitable for advanced SC applications.