Planar Patterning Design and Energy Storage Performance Comparison of Laser-Induced Graphene Flexible Supercapacitors

Laser-induced graphene (LIG) has gained significant attention due to its efficient and rapid production, and ability to create patterned electrodes. However, the operating voltage of LIG supercapacitor (LIG SC) unit devices is relatively low, and the different patterning LIG SC devices show different performances. Additionally, the size of the laser power also has a significant impact on the performance of the device. Herein, the energy storage performance of LIG SC devices in a variety of patterns and at different laser powers is investigated. The LIG SC device based on the interdigital pattern shows the best performance compared with the spiral pattern, mirror circular pattern, and concentric circular pattern LIG devices. When the laser power is 2.75 W, the area-specific capacitance of the interdigital LIG SCs is up to 10.78 mF cm^{- 2} at 0.2 mA cm^{- 2}, with a wide operating voltage (1.8 V) and a maximum energy density of 4.85 μWh cm^{- 2}. Additionally, it maintained 84.1% of its capacitance after 8000 charge-discharge cycles and achieved an area-specific capacitance of 8.33 mF cm^{- 2} when bent at an angle of 60°. This digital interpattern LIG device etched by a laser power of 2.75 W can provide important insights into the development of planar flexible supercapacitors.