Boosting flexible laser-induced graphene supercapacitors performance through double pass laser processing.

This study proposes a simple and cost-effective approach to enhance the performance of supercapacitors based on laser-induced graphene (LIG). The use of two consecutive laser passes using the same CO engraver on polyimide film led to the expansion in the size of the pores, the increase in the graphitization degree, and the densification of the produced material. These changes in the morphology and chemical structure of the LIG impacted positively its electrochemical performance when it was used as an electrode for supercapacitors. The best achieved material displayed the following results: (a) an enhancement of the areal energy density from 0.77 to 2.20 μWh/cm at 0.05 mA/cm, (b) a reduction of 60% in the equivalent series resistance, (c) high cycling stability with a capacitance retention rate of 91% after 10.000 cycles, (d) high performance stability under mechanical tests at different angles, and (e) green LED illumination under configuration in series.