In situ preparation of FeOx nanoparticles embedded N-doped laser-induced graphene for flexible in-plane micro-supercapacitors

Laser direct writing of polyimide (PI) film to induce porous graphene as a flexible electrode facilitates the development of efficient, low-cost, and large-scale preparation of flexible planar micro-supercapacitors (MSCs). Nevertheless, current flexible MSCs based on laser-induced graphene (LIG) face bottlenecks such as poor LIG electrode wettability, inhomogeneous doping of heterogeneous components, and limited electrochemical performance. In view of this, a simple and effective process for in situ fabrication of flexible FeO x nanoparticles embedded N-doped LIG (FeO x @NLIG) electrode is developed by laser direct writing in this study. The as-assembled in-plane FeO x @NLIG MSCs exhibit an excellent areal specific capacitance of 13.82 mF cm −2 , a remarkable energy density of 1.228 mW h cm −2 at a high power density of 0.024 mW cm −2 , good flexibility, and conspicuous cycling stability. Besides, these high-performance in-plane FeO x @NLIG MSCs as a vital micro-energy storage component can be easily miniaturized, modularized, and integrated to suit customized needs of wearable electronics due to great advantages in terms of identicality and stability of the as-fabricated FeO x @NLIG. Graphical abstract