Boosting Electric Double Layer Capacitance in Laser-Induced Graphene-Based Supercapacitors

Laser-induced graphene (LIG) is under the spotlight as a promising material for flexible supercapacitors due to its simple processing and flexibility. However, the poor conductivity and the reduced surface area have prompted research to improve its performance, traditionally introducing a pseudocapacitive behavior. Herein an effective yet easy way is presented to dramatically improve the electric double layer capacitance of LIG electrodes for supercapacitor-related applications without the occurrence of redox reactions. The strategy simply relies on the exploitation of an LIG network to trap and interconnect activated carbon (AC) particles. In order to optimize the infiltration of AC into LIG porosities, several strategies are tested, both varying the surface wettability of LIG and acting on the impregnation approach. Overall, the best compromise results in the combination of LIG N-doping by nitric acid incubation with vacuum-assisted infiltration of an AC-slurry, allowing a two-order of magnitude improvement in the specific capacitance up to 20 mF cm−2 in device configuration.