Laser-induced fabrication of porous graphene for flexible planar microsupercapacitors with wide voltage window

Herein, laser -induced graphene (LIG) derived from polyimide (PI) is demonstrated to construct a flexible planar interdigital microsupercapacitors (MSCs) device with wide voltage window through simple laser -direct -writing method. The mechanism study of LIG derived from PI show that the photon energy of the laser is absorbed by the electrons and converted into heat energy, and the rapid energy accumulation produces extremely high temperatures leading to the graphitization of PI film. At the same time, the internal expansion and gas escape from the interior, the graphitized carbon material grows upward, resulting in the formation of porous graphene. As a demonstration of the supercapacitor application, the as -prepared LIG MSCs device show excellent supercapacitance performance, wide voltage window (0 - 1.8 V) and good mechanical flexibility. When the laser power is 2.75 W, that is, 50 % of the maximum power, the resulting LIG MSCs device has a high specific capacitance of 20.85 mF cm -2 , a maximum energy density of 9.38 mu Wh cm -2 , and good cycle stability with a capacitance retention rate of 101.09 % after 15,000 cycles. This work provides a simple method to prepare graphene-based MSCs and demonstrates great potential of the LIG MSCs in flexible wearable electronic devices.