Stamping Fabrication of Flexible Planar Micro-Supercapacitors Using Porous Graphene Inks

High performance, flexibility, safety, and robust integration for micro-supercapacitors (MSCs) are of immense interest for the urgent demand for miniaturized, smart energy-storage devices. However, repetitive photolithography processes in the fabrication of on-chip electronic components including various photoresists, masks, and toxic etchants are often not well-suited for industrial production. Here, a cost-effective stamping strategy is developed for scalable and rapid preparation of graphene-based planar MSCs. Combining stamps with desired shapes and highly conductive graphene inks, flexible MSCs with controlled structures are prepared on arbitrary substrates without any metal current collectors, additives, and polymer binders. The interdigitated MSC exhibits high areal capacitance up to 21.7 mF cm^-2 at a current of 0.5 mA and a high power density of 6 mW cm^-2 at an energy density of 5 µWh cm^-2. Moreover, the MSCs show outstanding cycling performance and remarkable flexibility over 10 000 charge-discharge cycles and 300 bending cycles. In addition, the capacitance and output voltage of the MSCs are easily adjustable through interconnection with well-defined arrangements. The efficient, rapid manufacturing of the graphene-based interdigital MSCs with outstanding flexibility, shape diversity, and high areal capacitance shows great potential in wearable and portable electronics.