MOF-derived graphene/chromium oxide hybrids via laser processing for enhanced planar micro-supercapacitors

Abstract

Metal–organic framework (MOF)-derived carbons have emerged as exceptional electrode materials for supercapacitors, benefiting from their ultrahigh surface areas, tunable porous structures, and inherent metal/metal oxide species. This work demonstrates a one-step laser-scribing strategy to directly convert a polyimide/MIL-101(Cr) composite film into an integrated electrode of porous laser-induced graphene (LIG) and mixed-valence chromium oxides (CrOx) for flexible in-plane micro-supercapacitors. The resulting LIG/CrOx composite exhibits a threefold enhancement in specific surface area (130.45 m2/g) compared to pristine LIG, along with a narrow pore size distribution (3–5 nm). The incorporated mixed-valence CrOx nanoparticles provide pseudocapacitance and enhance interfacial charge transfer, while the robust LIG network ensures mechanical flexibility and structural integrity. These synergistic structural and electrical optimizations yield an extraordinary 18-fold increase in areal capacitance, achieving 13.48 mF/cm2 for LIG/CrOx-based planar micro-supercapacitors. The hybrid electrode maintains good cycling stability and mechanical flexibility. This study provides an efficient manufacturing pathway for high-performance flexible energy storage devices and advances the direct integration of MOFs into laser-fabricated electronic systems.