Aqeel Mohammed Abdul Mageeth1 Myunghwan Jeong1 Choongho Yu1

1, Texas A&M University, College Station, Texas, United States

Thermally chargeable planar supercapacitors are good candidates for energy harvesting and storage in wearable and internet-of-things (IoT) electronic devices. We report a graphene oxide based supercapacitor which can be thermally chargeable and has good areal capacitance and charge storage capability in conjunction with a shape memory polymer (SMP) to create a device operating in a cyclic manner having thermal charging and discharging cycles. The supercapacitor has reduced sulfate graphene oxide electrodes fabricated by laser irradiation on a film of graphene oxide over PET substrate using a 3D printer with laser diode assembly. Graphene oxide with H2SO4 acts as separator/electrolyte for the super capacitor. The fabricated supercapacitor employs the Soret effect as the transport mechanism, which results in high thermoelectric voltage. The shape memory polymer was prepared from EPON 826 resin with neopentyl glycol diglycidyl ether (NGDE) added at 1:1 molar ratio to have a glass transition temperature just above room temperature. The SMP after preparation was casted onto a rubber mold of desired shape made by 3D printing and cured to impart the final shape. An array of supercapacitor specimen modules were placed over the SMP film connected in series or parallel depending on the voltage and current requirements of the device application. Temperature gradients applied across the two ends of the SMP film were used for thermal charging, and a shape change was utilized for discharging when the applied temperature gradient raised the temperature of the SMP. The mechanism developed here can be easily integrated into various devices operating intermittently with low power consumption.