formation of CoO nanocrystals embedded in laser-induced graphene foam for high-energy flexible micro-supercapacitors.

The cost-effective synthesis of flexible energy storage devices with high energy and power densities is a challenge in wearable electronics. Here, we report a facile, efficient, and scalable approach for preparing three-dimensional (3D) laser-induced graphene foam (CoO@LIG) embedded with porous CoO nanocrystals using a CO infrared laser. The formed CoO@LIG nanocomposites directly serve as active materials, current collectors, and the conductive substrate for micro-supercapacitors (MSCs). Benefiting from rational structural features, the MSC based on CoO@LIG nanocomposites (CoO@LIG-MSC) with an interdigitated electrode configuration exhibits excellent electrochemical performance, including a high specific capacitance (143.5 F g), excellent rate capability, high energy density (19.9 W h kg at a power density of 0.5 W kg), and remarkable power density (15.0 W kg at an energy density of 15.8 W h kg). Furthermore, the device possesses good stability under different bending diameters and cycling stability. Such a highly integrated flexible MSC with high energy and power densities made by a directly laser scribing strategy has some potential for the fabrication of wearable energy storage devices.