Laser-engineered oxygen-vacancy-rich CeO2/graphene heterostructures for high-performance planar micro-supercapacitors

The planar miniature supercapacitors (PMSCs) based on laser-induced graphene (LIG) are promising miniaturized energy storage systems, yet their practical deployment is constrained by low areal capacitance and energy density. Herein, we report a synergistic strategy to boost the energy storage performance of LIG PMSCs by integrating the cerium dioxide (CeO2) nanoparticles into the three-dimensional (3D) LIG framework. Laser irradiation concurrently converts polyimide (PI) to 3D graphene and introduces abundant oxygen vacancies in CeO2, enhancing redox-active sites and electron transport. The optimized LIG/CeO2 PMSCs exhibit an areal capacitance of 27.54 mF cm−2 at 2 mV s−1 and delivers energy density of 3.98 μWh cm−2. This enhancement stems from the oxygen vacancies of CeO2, CeO2–LIG π-electron orbital interactions, and strong interfacial coupling—validated by density functional theory calculations to accelerate charge storage kinetics. This work provides a scalable route to high-performance LIG-based PMSCs for miniature energy storage with improved energy density.