Flexible, all-solid-state, high-cell potential supercapacitors based on holey reduced graphene oxide/manganese dioxide nanosheets

摘要

Abstract2D ultrathin nanomaterials have attracted a significant interest for their application in flexible and lightweight energy storage devices. In this work, we report the fabrication, by electrophoretic deposition (EPD), of flexible all-solid-state symmetric high cell potential supercapacitors, comprised of holey reduced graphene oxide – manganese dioxide nanosheets (HGM). HGM films were electrophoretically deposited in a layer-by-layer fashion onto targeted substrates, with net thicknesses ranging from 0.2 to 2.5?μm. The assembled HGM films were highly compact with the density of ～2.2?g?cm?3. The resulting symmetric HGM supercapacitors, using PVA-LiClO4gel as an electrolyte, exhibited excellent electrochemical capacitive performance over a wide cell potential window of 0.0–1.6?V. Operating at ultra-high charge-discharge rates, up to 5000?mV?s?1, the HGM supercapacitors delivered excellent areal specific capacitances of 12–46?mF?cm?2, corresponding to volumetric specific capacitances of 557–182?F?cm?3at thickness of 0.2–2.5?μm, respectively. Furthermore, the HGM supercapacitors exhibited long-term cycling stability with a retention over 80% of its initial capacitance after 2000 cycles. Considering the facile scale-up capability of the EPD process, our approach paves a promising route for the manufacture of next-generation flexible all-solid-state supercapacitors with high energy and high power density.Graphical abstractDisplay OmittedHighlights?Flexible solid state supercapacitors of HRGO–MnO2 nanosheets (HGM) were prepared.?Electrophoretic deposition was used to fabricate flexible electrodes.?HGM supercapacitors exhibited excellent volumetric energy density of 48.8?mWh cm-3.?HGM supercapacitors showed long lifespan with over 80% retention after 2000 cycles.]]>