Supersonic cluster beam printing of carbon microsupercapacitors on paper

Paper is a cheap, lightweight and renewable material with increasing applicative interest as a substrate for disposable and flexible electronics. The integration of planar energy storage devices on paper is a necessary and challenging step for the development of smart and autonomous flexible electronic platforms. Here we report the one-step, room temperature, fabrication of planar microsupercapacitors where nanostructured current collectors and carbon electrodes are deposited by supersonic cluster beam deposition (SCBD) on plain paper sheets and 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide ([Emim][NTf2]) is used as ionic liquid electrolyte. As-prepared microsupercapacitors showed a high capacitance density of about 7 F cm−3 and good capacity retention upon prolonged cycling. The encapsulation of SCBD-made microsupercapacitors by means of a polydimethylsiloxane layer and their usability in driving a low power temperature sensor are demonstrated.