A high-performance current collector-free flexible in-plane micro-supercapacitor based on a highly conductive reduced graphene oxide film

A flexible in-plane micro-supercapacitor (MSC) was fabricated by laser carving a highly conductive and mechanically robust reduced graphene oxide (rGO) film adhered to a polyethylene naphthalate (PEN) sheet, followed by electrochemical activation of its microelectrodes. The laser carved rGO film can readily produce rGO interdigital micropatterns on a flexible PEN substrate, whereas electrochemical post-treatment can efficiently exfoliate the highly stacked rGO microelectrodes into a porous three-dimensional interconnected porous microstructure, greatly enhancing the accessible surface area for the formation of electrical double layers. The resultant metal current collector-free, flexible in-plane MSC exhibited a high areal specific capacitance, superior rate capability, excellent cycling stability as well as outstanding flexibility.