Laser-induced fabrication of In2O3-incorporated surface defects-enriched porous graphene electrodes for high-performance supercapacitors with excellent mechanical flexibility and cyclability

Electronic devices are trending toward smaller, thinner, lighter, and more flexible designs. Laser-induced graphene (LIG) is a cost-effective, flexible, and electrically superior alternative for next-gen wearable and portable gadgets. However, LIG-based supercapacitors (LIG-SCs) face limitations in practical use due to their low energy density, owing to the small surface area of LIG electrodes and few electrochemically active sites. To address these limitations, the current work employs a two-step laser scanning strategy to in situ synthesize interdigitally structured three-dimensional porous In 2 O 3 -LIG composite electrodes. The prepared In 2 O 3 -LIG-4-9.5-SC device demonstrates remarkable performance enhancements: an areal specific capacitance of 60.5 mF/cm 2 at 20 μA/cm 2 current density (representing a 115-fold improvement over pristine LIG), coupled with superior power density (0.008 mW/cm 2 ) and energy density (5.38 μWh/cm 2 ). Furthermore, the device exhibits exceptional cycling stability with 90.1% capacitance retention after 10,000 charge–discharge cycles, along with stable performance under various bending conditions. The two-step laser scanning protocol works synergistically to create almost dual enhancements. It increases the surface area through secondary scanning and enriches the LIG framework with C-C=O hydrophilic functional groups. Meanwhile, the incorporation of In 2 O 3 nanoparticles introduces structural disorders or defects and additional electrochemically active sites into the LIG framework. This synergistic optimization mechanism effectively overcomes the inherent limitations of LIG-SCs.