In Situ Co-60 Gamma-Ray Irradiation-Assisted Growth of SnO ₂ Nanoparticles onto MWCNTs: Strategic Approach to Design Large-Area Solid-State Supercapacitor Prototyping

A unique in situ cobalt-60 (Co-60) gamma-ray irradiation-assisted chemical route has been employed to synthesize SnO 2 nanoassembly onto a MWCNTs nanonetwork to design a large-area (10 cm × 4 cm) prototype solid-state supercapacitor. The MWCNTs-SnO 2 nanocomposite has been characterized through structural, surface morphological, valence state, and zeta potential analysis. The active nanocomposite coated on stainless steel (SS) as a working electrode demonstrated an excellent voltage window of 1 V enabling the specific capacitance of 430 F/g at a scan rate of 5 mV/s, with the capacitive retention of 91.9% retained over 5000 cycles. The designed large-area symmetric solid-state device with the configuration SS/MWCNT/SnO 2 //PVA-LiClO 4 //SnO 2 /MWCNT/SS exhibited a wider operating potential of 2 V with a specific capacitance of 61.1 F/g at 5 mV/s, along with 69.9% capacitance retention after 5000 cycles. To gain insight into real-world applications, the designed device powered two LED panels (BARC-VNIT) consisting of 70 LED lights and run a small dc fan along with displaying 2 V on a digital multimeter.