High-performance La2FeO4–rGO nanocomposite as an advanced ruddlesden–popper electrode for next-generation supercapacitors

As the transition away from fossil fuels accelerates, the demand for sustainable and efficient energy storage systems is increasing. Supercapacitors, particularly symmetric and asymmetric types, are emerging as key contenders due to their high-power density, long cycle life, and rapid charge–discharge capabilities. A major focus in this field is the development of advanced electrode materials with well-controlled composition and structure. Ruddlesden-Popper (RP) oxides, with the general formula An+1BnO3n+1, are gaining attention for their structural stability, high oxygen vacancy concentration, and excellent redox properties. In this work, La2FeO4 was synthesized via a solid-state method, and reduced graphene oxide (rGO) was prepared using a modified Hummer’s method. A series of La2FeO4/rGO nanocomposites with varying weight ratios were fabricated through a hydrothermal route. Structural and morphological characterization was conducted using XRD, Raman spectroscopy, SEM, HR-SEM, HR-TEM, and BET surface analysis. Electrochemical studies in 3M KOH electrolyte demonstrated that the La2FeO4-rGO (1:4) composite exhibited the best performance. Symmetric supercapacitors (SSCs) based on this material delivered a high capacitance of 633 F/g at 1 A/g, while asymmetric supercapacitors (ASCs) showed 197 F/g under similar conditions. Both devices showed excellent cycling stability and coulombic efficiency, with SSCs and ASCs retaining 91.1% and 99.9% of their initial capacitance, and efficiencies of 99.5% and 74%, respectively. Maximum energy and power densities reached 148 Wh/kg and 7.8 kW/kg for SSCs, and 70 Wh/kg and 20 kW/kg for ASCs. These findings highlight the strong potential of La2FeO4-rGO nanocomposites as high-performance electrode materials for next-generation energy storage applications.

Figure. A schematic diagram of the charge/ discharge process.

Harish Verma received his Master of Philosophy (M.Phil.) degree in 2020. He joined the Ph.D. program in the Department of Physics at the Indian Institute of Technology (IIT) BHU, Varanasi, Uttar Pradesh, India, in 2021. His research focuses on advanced energy storage devices, particularly supercapacitors and batteries. He is working on the synthesis and characterization of energy materials such as perovskites, two-dimensional nanomaterials including graphene oxide, MXene, MoS₂, as well as eco-friendly materials derived from biowaste. Currently, he is also developing skills in density functional theory (DFT) and simulation techniques like COMSOL Multiphysics to better understand and model electrochemical systems.