High-efficiency femtosecond laser fabrication of graphene-hybrid planar micro-supercapacitors with micro/nanostructured electrodes

The integration of surface-regular micro/nanostructured electrodes within a limited footprint area is promising to enhance the electrochemical performance of planar micro-supercapacitors (P-MSCs), while developing simple yet efficient manufacturing methods for such electrodes remains a challenge. Here, we propose a universal strategy combining femtosecond laser plasma lithography with spatial light modulation (SLM-FPL), fabricating well-ordered sub-wavelength micro/nanostructured electrodes of interdigital P-MSCs (SEP-MSCs) on graphene oxide (GO) films. Achieving 500/50 µm finger widths/spacings and 680 nm internal grating periods, this method enables device densities >25 units inch^-2 with processing efficiency orders of magnitude higher than conventional laser direct writing. Further performance optimizations via wettability modification, electric field engineering, and hybrid composites (GO-MXene/COF) yield outstanding specific capacitance (~41.4 F cm^-3) and cycling stability (93% retention over 5000 cycles), supporting applications in flexible sensors and compact power supplies. This SLM-FPL technology shows strong potential for high-performance, spatially efficient SEP-MSCs in next-generation integrated systems.