Risma Aimatul Qudsiyah, Heydar Ruffa Taufiq, Priyono, Markus Diantoro, Agus Purwanto, Worawat Meevasana, Agus Subagio
The increasing global energy demand driven by population growth and urbanization has intensified the need for sustainable energy storage solutions. Supercapacitors are attractive candidates owing to their high power density, rapid charge–discharge capability, and long cycle life; however, the development of environmentally friendly electrode materials remains a challenge. In this work, banana peel extract was employed as a green reducing agent for the hydrothermal synthesis of reduced graphene oxide (rGO)/manganese dioxide (MnO₂) nanocomposites at 140, 160, and 180 °C. This green approach aims to minimize the use of hazardous chemicals while valorizing agricultural waste. Structural and morphological analyses confirmed the successful formation of the composite, with temperature-dependent phase transitions and distinct morphologies. Electrochemical measurements revealed that the rGO/MnO₂ electrode synthesized at 140 °C delivered the highest specific capacitance of 601.41 F g⁻¹ at 0.5 A g⁻¹, outperforming those prepared at 160 °C (147.69 F g⁻¹) and 180 °C (549.09 F g⁻¹). These findings demonstrate that controlling the hydrothermal synthesis temperature significantly influences the composite's electrochemical properties. Therefore, banana peel-derived rGO/MnO₂ synthesized at 140 °C exhibits excellent capacitive performance, highlighting its potential as a sustainable electrode material for high-performance supercapacitors. © 2026, Walailak University. All rights reserved.
Department of Physics, Faculty of Science and Mathematics, Diponegoro University, Semarang, 50275, Indonesia; Department of Physics, Faculty of Mathematics and Natural Science, Universitas Negeri Malang, Malang, 65145, Indonesia; Department of Chemical Engineering, Faculty of Engineering, Universitas Sebelas Maret, Central Java, 57126, Indonesia; Department of Physics, Faculty of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand
