Sushant Kumar, Isha Kumari, Manoj K. Singh, Vinay Deep Punetha, Pawan Singh Dhapola, Monika Michalska, Markus Diantoro, Pramod K. Singh
The growing demand for sustainable, high-performance, and environmentally benign energy storage systems has intensified interest in bio-waste-derived electrode materials and advanced solid-state electrolytes that can improve both energy density and device safety. This study introduces an innovative approach for developing solid-state supercapacitors by synthesizing activated carbon from Moringa oleifera flowers (MF) via ZnCl2-assisted chemical activation followed by carbonization. The resulting activated carbon (MFAC) was characterized using XRD, BET, Raman spectroscopy, SEM, TEM, EDX, and XPS, confirming its amorphous structure, high surface area, and well-developed hierarchical porous morphology. The use of Moringa oleifera flowers provides a renewable and underexplored carbon precursor with favorable surface chemistry for electrochemical charge storage. Additionally, a redox-active, nonaqueous gel polymer electrolyte was formulated using the ionic liquid 1-ethyl-3-methylimidazolium tricyanomethanide (EMImTCM) and sodium iodide (NaI) within a poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) matrix. Two symmetric solid-state supercapacitor cells were fabricated: one using the base ionic liquid gel polymer electrolyte (Cell#1) and the other incorporating NaI as a redox additive (Cell#2). Electrochemical analysis through cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy revealed significantly enhanced performance for Cell#2, delivering a specific capacitance of 283 F g−1 and an energy density of 39 Wh kg−1, compared to 98 F g−1 and 14 Wh kg−1 for Cell#1, due to additional iodide-mediated faradaic reactions. Moreover, Cell#2 exhibited excellent cycling stability, retaining ∼80% of its capacitance after 5000 cycles at 1 A g−1. This work demonstrates a sustainable, scalable strategy for enhancing the performance of solid-state supercapacitors by synergistically integrating bio-derived porous carbon electrodes with redox-active gel polymer electrolytes. © 2026 Elsevier B.V.
Department of Physics, School of Physical Sciences, Starex University, Haryana, Gurugram, 122413, India; Centre of Excellence in Solar Cell and Renewable Energy, Department of Physics & Environmental Sciences, Sharda School of Engineering & Science (SSES), Sharda University, Uttar Pradesh, Greater Noida, 201306, India; Department of Chemistry, University of Delhi, Delhi, 110007, India; Energy Conversion & Storage Lab, Department of Applied Science & Humanities, Rajkiya Engineering College Banda, AKTU, Uttar Pradesh, 210201, India; Centre of Excellence for Research, P P Savani University, NH 8, GETCO, Kosamba, 394125, India; Department of Chemistry and Physico-Chemical Processes, Faculty of Materials Science and Technology, VŠB-Technical University of Ostrava, 17. Listopadu 2172/15, Ostrava-Poruba, 708 00, Czech Republic; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Department of Physics, Graphic Era (Deemed to be University), Clement Town, Dehradun, India
