Scalable Fabrication of Flexible Supercapacitor Electrodes Using Sustainable Water-Based Onion-like Carbon Inks

The increasing usage of electrical energy storage solutions demands for cost effective, scalable and sustainable manufacturing technologies. Deposition of functional inks, carrying electrochemically active materials is a suitable technique as it delivers material with selected properties only to required locations. However, the production of stable dispersions featuring high concentrations of active material - necessary for effective deposition - is challenging. Here we present an approach to print supercapacitor electrodes with onion-like carbon as active material, using a simple, cost-effective process as well as a water-based ink. The ink is highly stable and can be deposited by spray and inkjet techniques. The fabricated electrodes offer a capacitance of up to 14 mF cm(-2) (27 F g(-1)) and retained 97 % of their initial capacitance after 5000 cycles, demonstrating excellent performance and stability of the coating.