Aqueous manganese dioxide ink for paper-based capacitive energy storage devices

摘要

We report a simple approach based on a chemical reduction method to synthesize aqueous inorganic ink comprised of hexagonal MnO2 nanosheets. The MnO2 ink exhibits long-term stability and continuous thin films can be formed on various substrates without using any binder. To obtain a flexible electrode for capacitive energy storage, the MnO2 ink was printed onto commercially available A4 paper pretreated with multiwalled carbon nanotubes. The electrode exhibited a maximum specific capacitance of 1035 Fg-1 (91.7 mFcm-2). Paper-based symmetric and asymmetric capacitors were assembled, which gave a maximum specific energy density of 25.3 Whkg-1 and a power density of 81 kWkg-1. The device could maintain a 98.9% capacitance retention over 10000 cycles at 4 Ag-1. The MnO2 ink could be a versatile candidate for large-scale production of flexible and printable electronic devices for energy storage and conversion. Printing the future: A simple chemical reduction method has been used to synthesize aqueous MnO2 ink that exhibits long-term stability and can form continuous thin films on various substrates without the need for any binder. The as-prepared MnO2 ink can also be coated onto conductive A4 paper to form capacitive energy storage devices.