Laser Scribing of Fluorinated Polyimide Films to Generate Microporous Structures for High-Performance Micro-supercapacitor Electrodes

Laser-induced graphene (LIG) typically exhibits a mesostructure with a small specific surface area, which is detrimental to the electrochemical performance of micro-supercapacitors (MSCs). Herein, 3D nanostructured LIGs patterned on fluorinated polyimides (fPIs) via a laser photothermal method are reported. During laser-induced graphitization, a highly microporous structure in the LIG develops. Consequently, the patterned LIG (LIG-fPI) exhibits a very large specific surface area (1126.0 m2 g–1), thereby enhancing its electrochemical performance. Specifically, in an H2SO4 aqueous electrolyte, the micropatterned electrode exhibits an exceptional areal capacitance of 110 mF cm–2 (determined by cyclic voltammetry), which is 27 times higher than that of a LIG based on commercial polyimides and at least 7 times higher than that of current state-of-the-art MSCs. Furthermore, mechanically stable and flexible LIG-fPI-MSCs with an organic gel polymer electrolyte (working potential = ∼3 V) show very high power and energy densities of 0.58 mW cm–2 and 0.01 mW h cm–2, respectively. Thus, these LIGs are promising for application in high-performance MSCs for flexible microelectronics.