Scalable fabrication of High-Rate On-Paper Microsupercapacitors through full inkjet printing

Abstract: storage devices in micro sizes are receiving more and more attention. One of them, on-paper Microsupercapacitors (MSCs), has become a key energy storage device because of its good mechanical flexibility and high power density. In this project, a triphase system with electrochemically exfoliated graphene and graphene quantum dots to synergistically stabilize PEDOT:PSS in ethylene glycol/water solvent was developed for scalable and reliable inkjet printing. Without any post-treatment, the printed patterns with a large thickness (up to 9 μm, about 0.4 μm per layer) attain a sheet resistance of as low as 4 Ω2−1 and high resolution at a small drop spacing of 10 μm. Thanks to these feature, the areal capacitance of the on-paper MSCs can reach >2 mF cm−2 at a high scan rate of 1000 mV s−1. The device also exhibits excellent mechanical flexibility, long cycle life (>95% capacitance retention after 10000 cycles CV test) and long service time (retain 84% capacitance after 4 months in air without any encapsulation). Moreover, we can directly print the interconnect to connect 4 devices on paper substrate in series or in parallel and thus get rid of metal current collector.