Unveiling redox-boosted mesoporous Co@NiO–SiO₂ hybrid composite with hetero-morphologies as an electrode candidate for durable hybrid supercapacitors

The nanoscale morphology and mesoporosity have a substantial effect on the energy storage properties because they offer a high surface area and porous nature. The former one bestows the accessibility of more redox-active sites, while the latter facilitates the easy entry of foreign atoms. In this report, we rationally synthesized the mesoporous NiO–SiO₂ material with hetero-morphologies by a simple wet-chemical method, followed by calcination. The hetero-morphologies include nanospheres, nanoflakes, and nanoparticles collectively increased the surface area. To further increase the redox activity, the cobalt was hydrothermally doped to the NiO–SiO₂ material (Co@NiO–SiO₂). Consequently, the Co@NiO–SiO₂ electrode demonstrated superior electrochemical response with a higher capacity of 41.7 μAh cm⁻² compared to the NiO–SiO₂ electrode (25 μAh cm⁻²) in a three-electrode system. Moreover, the Co@NiO–SiO₂ electrode was sustained up to 10,000 cycles by retaining 95.5% of its initial capacity. The ability of the Co@NiO–SiO₂ material towards practical applicability was also unveiled by fabricating a hybrid supercapacitor (HSC). The HSC delivered a notable energy density (42.3 μWh cm⁻²) and power density (10.2 mW cm⁻²). Furthermore, the HSC exhibited outstanding durability (10,000 cycles) without fading. The ability of HSC was also tested by energizing light-emitting diodes.