Nano‐Architectonics of Porous α‐ Fe ₂ O ₃ for High‐Performance Asymmetric Supercapacitor Applications

The advancement of sustainable energy storage systems is crucial to address the growing global energy demands and environmental challenges. In this study, we demonstrate the sustainable synthesis and electrochemical assessment of porous α‐Fe 2 O 3 nanostructures for asymmetric supercapacitor applications. Two‐different synthetic approaches such as green‐method from Aristolochia bracteate and conventional combustion method were employed to synthesize α‐Fe 2 O 3 , enabling a comparative analysis of morphological, structural, and electrochemical characteristics. XRD analysis confirmed the rhombohedral phase of α‐Fe 2 O 3 with high crystallinity in both samples. FESEM and HRTEM micrographs revealed well‐defined porous structures with increased surface roughness and uniform particle dispersion in the green‐synthesized sample, promoting enhanced ion accessibility. The green‐electrode reveals maximum half‐cell specific capacitance of 914 F/g at 1 A/g in alkaline electrolyte. The asymmetric device with the green‐electrode as the cathode and commercial carbon as the anode demonstrated maximum full‐cell specific capacitance of 130 F/g at 1 A/g, with maximum energy and power density of ~18 Wh/kg and ~1663.74 W/kg at 1 and 10 A/g, respectively. These enhanced properties are attributed to the hierarchical porous structure, improved conductivity, and eco‐friendly synthesis approach, which contribute to sustainable material development. This study delivers the potential of green‐synthetic strategies in producing cost‐effective, environmentally benign, and electrochemically efficient materials for next‐generation supercapacitors.