A surface-mount flexible micro-supercapacitor on ultra thin parylene-C substrate

This paper reports a surface-mount flexible micro-supercapacitor employing a thin parylene-C membrane (10 μm) as the substrate and activated carbon (AC) as the electrodes. A thin parylene-C layer was deposited on a Si wafer by chemical vapor deposition (CVD) without silanization and then peeled off mechanically with the fabricated interdigital electrodes on it. The prototypes show a specific capacitance of 31 mF/cm² in the solid electrolyte (PVA-H₃PO₄). After 15 bending cycles, no obvious degradation in capacitance was observed. The prototype without separator also have been demonstrated, after more than 40 bending cycles, the capacitance changes from 20.6 mF/cm² to 19.3 mF/cm² with increasing bending cycles and the capacitance retention is 93.7% which indicates that the fabricated devices have good mechanical and electrochemical stability. Our method and design offer an opportunity to apply energy storage devices for wearable electronics.