Co-electro-deposition of the MnO2–PEDOT:PSS nanostructured composite for high areal mass, flexible asymmetric supercapacitor devices

Abstract

To meet the rapidly growing demand, it is necessary to develop novel flexible energy storage devices with a high energy density in a limited area, a fast charging ability, a low cost for mass production and a miniaturized device size. To address the above issues, here we introduce the co-electro-deposition strategy, which is able to prepare an electrode material with a high areal capacitance (1670 mF cm⁻² at 0.5 mA cm⁻²), a high areal mass (8.5 mg cm⁻²), an excellent mechanical robustness, a high through-put and great convenience even on a piece of a ubiquitous stainless steel mesh current collector. Based on this advancement, we are able to obtain an ultrathin (less than 200 μm) aqueous asymmetric supercapacitor device with a high energy density (1.8 × 10⁻³ W h cm⁻³), a high power density (0.38 W cm⁻³ at 3.62 × 10⁻⁴ W h cm⁻³) and an excellent rate capability. This energy storage device is integrated into a prototype smart card to drive a light emitting diode (LED) indicator, which is charged for 5 seconds and can light up the indicator for more than 2 hours, demonstrating great promise in miniaturized novel flexible energy storage devices.