Unravelling the Growth Mechanism of Nanotorous ZrO2-NiO Binary Composite and its Electrochemical Study for Supercapacitor Application

Present work reports on the synthesis of NiO-incorporated nanotorous ZrO₂ synthesized by facile co-precipitation method for supercapacitor application. The as-synthesized composite was characterised using FTIR and XRD confirming the successful synthesis of ZrO₂-NiO composite (ZNC). FESEM analysis also revealed morphology transition from nanoclusters of tiny ZrO₂ particles and stacked flakes of NiO to self-assembled nanotorus ZNC. Electrochemical analyses (like CV, GCD, EIS) also revealed improved electrochemical behaviour of ZrO₂ whose specific capacitance increased from 87.77 F/g to 251 F/g in ZNC at 1 A/g. This could be attributed to the synergistic effect of nanotorous morphology in the presence of NiO. These observations were well complemented by a reduced band gap (~ 2.96 eV) and lower charge transfer and solution resistance. A mechanistic insight was also proposed for a deeper understanding of the development of torous structured material. This work provides a closer look into how NiO-driven torous morphology of ZrO₂-NiO composite has improved the electrochemical performance of ZrO₂.