Aloe vera-derived NiCo2O4 electrodes with improved cyclic efficiency for supercapattery applications

Abstract

Green synthesis is a sustainable and environmentally friendly approach for designing efficient electrode materials to meet the growing demand for supercapattery electrodes. In this work, Aloe vera-assisted synthesis of phase-pure spinel NiCo2O4 nanomaterial was achieved through a simple and eco-friendly route. Synchrotron XRD confirmed excellent crystallinity and phase purity, while FTIR identified characteristic metal-oxygen bonds together with Aloe vera-derived organic functionalities. FESEM and TEM provided morphological insights, while BET analysis, confirming mesoporosity with a surface area of 18.61 m2 g−1, and average pore diameter of ~ 14.7 nm. Synchrotron XPS revealed mixed Ni/Co oxidation states and abundant oxygen vacancies, which promote enhanced redox activity and rapid charge-transfer kinetics. The Alv-NiCo2O4 electrode exhibited high specific capacitance (609.6 F g−1 at 5 mV s−1; 471.1 F g−1 at 1 A g−1), excellent rate capability, and long-term durability, retaining 97% capacitance and 99.6% coulombic efficiency over 5000 charge-discharge cycles at 20 A g−1. These findings demonstrate that Aloe vera-derived NiCo2O4 is a cost-effective, sustainable, and high-performance green electrode for supercapattery applications.