Study of structure and electrochemical properties of LaFeO₃ and La₂FeO₄ as electrode materials for super-capacitor application

Perovskite oxides have introduced a new advancement in the field of energy storage technologies. Because of their outstanding properties, perovskite oxides are a diverse and exciting class of compounds that have attracted a lot of interest. Perovskite oxides have attracted considerable interest as potential electrode materials for supercapacitors due to their unique structure, compositional flexibility, and intrinsic oxygen vacancy. Synthesized single-phase perovskite LaFeO₃ and its 2D equivalent Ruddlesden-Popper oxide La₂FeO₄ were obtained via a solid-state reaction method. X-ray diffraction and field emission scanning electron microscopy have been used to study the crystal structure and surface morphology of the produced materials, respectively. The optical band gap for LaFeO₃ is 2.10 eV, while for La₂FeO₄, it is 2.04 eV, as determined by UV-vis measurements. Electrochemical impedance spectroscopy (EIS), charge/discharge analysis, and cyclic voltammetry have all been used to study the electrochemical characteristics. Both of the samples exhibited typical pseudocapacitor behavior, as indicated by the presence of a redox peak in cyclic voltammetry, which was recorded in the potential window of 0 to -1 V. For both compounds, the faradic charge transfer resistance (Rct) was determined to be close to ~ 1 Ω. After 100 cycles of testing the charge/discharge characteristic, the specific capacitance of LaFeO₃ and La₂FeO₄ in a 3M KOH electrolyte solution stabilized at around 6 Fg-1 and 10 Fg-1, respectively.