Transition of interfacial capacitors in electrowetting on a graphite surface by ion intercalation.

摘要: The low voltage electrowetting response of a LiCl aqueous solution on freshly cleaved surface highly oriented pyrolytic graphite (HOPG) is presented. For applied voltages below 1 V, the energy stored in electrical double layer (EDL) insufficient to drive spreading drop due pinning three phase contact line at step edges. Electrochemical impedance spectroscopy shows dramatic increase capacitance above which provides sufficient force for depinning line, resulting subsequent decrease angle. transition interfacial from EDL many-fold high pseudocapacitor drives HOPG surface. observed changes capacitances V are correlated with cyclic voltammetry and atomic microscopy results, show that Cl− ions intercalate into galleries upon acquiring overcome van der Waals attraction between graphene layers through side edge basal planes. To best our knowledge, this first study dependent intercalation mediated driving an electrolyte surface, fundamental understanding mechanism opens up potential applications microfluidics charge storage technologies.