Mesoporous oxygen vacancy 3D-rhombohedral Ov-Mn2O3 mixed with rGO@CNTs as cathode material for self-charging pouch-type hybrid supercapacitor applications

The extrinsic integrated self-charging pouch-type hybrid supercapacitors (HSCs) are much more interesting and persuade advance research in worldwide. In HSC, the electrodes and electrolytes are playing a crucial role. Hence, the prepared cathode material's uniform morphology with mesoporous, presence of rich oxygen vacancy, high electrical/ionic conductivities, and addition of redox additives in electrolyte could significantly achieve high charge storage capacity and improved device performance. Initially, the Mn2O3 shows a high specific capacity of 31.03 mAh/g at 6 mA/cm2 in KOH plus redox additives electrolyte compared to pristine KOH electrolyte (21.75 mAh/g). Further, the optimized Ov-Mn2O3@rGO/CNTs composite sample exhibits superior battery-type behavior. The composite sample delivers a maximum specific capacity of 82.91 mAh/g at 6 mA/cm2, superior rate capability of 49.83%, and long cycle retention of 97.27% after 5000 cycles. Then, the pouch-type HSCs were fabricated using rich Ov-Mn2O3@rGO/CNTs/Ni as battery-type cathode and AC/Ni as a capacitive-type anode. The device delivered a maximum specific energy density of 44.97 Wh/kg at a power density of 847 W/kg with superior capacity retention of 85.41% after 13,000 cycles. Finally, the fabricated HSC devices have been integrated with thermoelectric generator and solar cell to prove for future sustainable self-charging applications.