(September 23, 2015) The Department of Applied Physics of The Hong Kong
Polytechnic University (PolyU) has developed a simple approach to synthesize
novel environmentally-friendly manganese dioxide (MnO2) ink by using glucose.
The MnO2 ink could be used for the production of light, thin, flexible and high
performance energy storage devices via ordinary printing or even home-used
printers. The capacity of the MnO2 ink supercapacitor is more than 30 times
higher than that of a commercial capacitor of the same weight of active
material (e.g. carbon powder), demonstrating the great potential of MnO2 ink in
significantly enhancing the performances of energy storage devices, whereas its
production cost amounts to less than HK$1.
MnO2 is a kind of environmentally-friendly material and it
is degradable. Given the environmental compatibility and high potential
capacity of MnO2, it has always been regarded as an ideal candidate for the
electrode materials of energy storage devices. The conventional MnO2 electrode
preparation methods suffer from high cost, complicated processes and could
result in agglomeration of the MnO2 ink during the coating process, leading to
the reduction of electrical conductivity. The PolyU research team has developed
a simple approach to synthesize aqueous MnO2 ink. Firstly, highly crystalline
carbon particles were prepared by microwave hydrothermal method, followed by a
morphology transmission mechanism at room temperature. The MnO2 ink can be
coated on various substrates, such as conductive paper, plastic and glass. Its
thickness and weight can also be controlled for the production of light, thin,
transparent and flexible energy storage devices. Substrates coated by MnO2 ink
can easily be erased if required, facilitating the fabrication of electronic
devices.