Eco‐Conscious Fabrication of SrO ₂ Nanostructures From Dioscorea Bulbifera Leaf Extract: A Dual Performance Electrode for Advancing Sustainable Energy D

ABSTRACT

The supercapacitors and electrocatalysts based on advanced nanostructured metal oxides are emerging as pivotal components for next‐generation sustainable energy storage and conversion systems. An eco‐conscious and scalable synthesis of strontium dioxide (SrO ₂ ) nanostructures is achieved using dioscorea bulbifera leaf extract, which acts as a natural reducing, capping, and stabilizing agent. This green synthesis approach enables the formation of hierarchically organized SrO ₂ architectures composed of interconnected nanorods embedded with nanoparticles, providing abundant electroactive sites and enhanced ion diffusion pathways. The binder‐free SrO ₂ electrode directly deposited onto a stainless‐steel substrate exhibits a high specific capacity of 1117 C g ⁻¹ at 4 A g ⁻¹ in a three‐electrode configuration, along with cycling stability, retaining 89.8% capacity after 6000 cycles. The asymmetric solid state supercapacitor device (SrO ₂ ||1 M PVA‐KOH||AC) demonstrates an energy density of 91 Wh kg ⁻¹ at a power density of 901 W kg ⁻¹ , with superior cycling durability of 95.8% over 7000 cycles. The SrO ₂ nanostructures exhibit oxygen evolution reaction (OER) activity, delivering a low overpotential of 343 mV at 10 mA cm ⁻² and a small Tafel slope of 41.7 mV dec ⁻¹ , indicating favourable reaction kinetics and efficient charge transfer, while also showing long‐term electrochemical durability under continuous operation.