Tailored nitrogen-doped laser-induced graphene from modified polyimide precursors for high-performance flexible planar micro-supercapacitors

The development of flexible and wearable electronics necessitates miniaturized energy storage systems with high performance. Spatial constraints are addressed by in-plane micro-supercapacitors (MSCs) via their planar architectures, yet progress is hampered by limitations in electrode materials. A single-step laser direct writing approach is reported here to fabricate nitrogen-doped laser-induced graphene (NLIG) electrodes from modified polyimide (PI) precursors. In situ nitrogen doping is achieved during laser carbonization by utilizing polyimide synthesized from poly(amic acid) containing homogeneously pre-dispersed, nitrogen-rich 1,10-phenanthroline. A three-dimensional (3D) porous architecture is exhibited by the resultant NLIG, with significantly enhanced wettability and optimized electronic structure. These features underpin the MSCs' high areal capacitance (8.81 mF·cm⁻² at 0.5 mA·cm⁻²), excellent cycling stability, and robust mechanical flexibility. Electrochemical performance metrics are maintained across both individual devices and integrated configurations. This scalable methodology for producing NLIG electrodes presents a promising, potentially cost-effective route towards high-performance flexible energy storage solutions crucial for next-generation wearable and portable electronic systems.