Femtosecond laser induced one-step nanopatterning and preparation of rGO/RuO₂ electrodes for high-performance micro-supercapacitors

Due to the tremendous importance of miniaturized energy harvesting devices for implantable and wearable electronics, numerous new materials and electrode architectures for micro-supercapacitors (MSCs) have emerged in recent years. Hybrid electrodes based on transition metal oxides and carbon-based materials are considered to be promising candidates to overcome the relatively low energy density of pure carbon materials. However, the complicated preparation process limited its development. Herein, a facile method of simultaneous nanopatterning and preparation of reduced graphene oxide (rGO)/RuO₂ nanocomposite electrodes by femtosecond laser irradiation is proposed. The RuO₂ nanoparticles and filaments structures are successfully anchored to rGO surfaces through a redox reaction of graphene oxide (GO) and RuCl₃. On this basis, the binder-free, metal current collector-free rGO/RuO₂ electrodes are constructed. The as prepared rGO/RuO₂ MSCs deliver an areal capacitance of 2.35 mF/cm² and 90% capacitance retention after 4000 charge-discharge cycles. The synergic effect between rGO and RuO₂ nanoparticles enables the high-performance of rGO/RuO₂ hybrid electrodes. This research enables the one-step manufacturing of carbon/pseudocapacitor hybrid electrodes, showing great promise for next generation flexible displays and wearable electronic devices.