Flexible, ionic liquid-based micro-supercapacitor produced by supersonic cluster beam deposition

Power generation and storage in electronics require flexible, thin micro-electrochemical energy storage/conversion systems. Micro-supercapacitors (μSCs) with double-layer capacitance carbon electrodes are attracting much attention for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. Supersonic Cluster Beam Deposition (SCBD) is an effective strategy for the development of nanostructured, binder-free porous carbon electrodes on temperature sensitive substrates including polymers. We exploited SCBD for the development of a flexible, planar μSC featuring nanostructured carbon (ns-C) electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N<inf>1113</inf>TFSI) ionic liquid electrolyte. The electrochemical performance at different temperatures of the μSC which operates at 3 V above RT up to 80°C with a capacitance density approaching 10 F cm^-3 and delivering maximum specific energy and power densities of 10 mWh cm^-3 and 8-10 W cm^-3 with long cycling stability over 2 × 10⁴ cycles is here reported and discussed.