Piezoelectric Inkjet Printing of Nanoporous Carbons for Micro-supercapacitor Devices

High-resolution interdigital micro-supercapacitor (MSC) devices are produced by one-step printing of liquid carbon precursors based on renewable resources. A piezo-driven micro-pipetting system allows precise positioning of the ink, offering a high degree of variability in terms of geometric supercapacitor designs. The printed precursor structures were directly converted into nanoporous carbon materials by pyrolysis at 900 °C. A hydrogel electrolyte based on PVA/H2SO4 was used to form quasi-solid-state MSCs. Stable structures with an ohmic serial resistance of around 540 Ω and capacitance up to 151 F cm–3 (3.9 mF cm–2) could be produced via additional nitrogen doping of the nanoporous carbon. The capacitance retention of piezoelectric-printed structures after 10,000 cycles remains as high as 96%.