In situ formation of Co3O4 nanocrystals embedded in laser-induced graphene foam for high-energy flexible micro-supercapacitors

Abstract

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 (Co₃O₄@LIG) embedded with porous Co₃O₄ nanocrystals using a CO₂ infrared laser. The in situ formed Co₃O₄@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 Co₃O₄@LIG nanocomposites (Co₃O₄@LIG-MSC) with an interdigitated electrode configuration exhibits excellent electrochemical performance, including a high specific capacitance (143.5 F g⁻¹), excellent rate capability, high energy density (19.9 W h kg⁻¹ at a power density of 0.5 W kg⁻¹), and remarkable power density (15.0 W kg⁻¹ at an energy density of 15.8 W h kg⁻¹). 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.