AsianScientist (Oct. 2, 2015) – Researchers have developed a manganese dioxide (MnO2)-based ink that has a capacity 30 times higher than what is commercially available. Their work, published in Angewandte Chemie, has the potential to cut the production costs and environmental burden of manufacturing energy storage devices.
MnO2 is an eco-friendly material and is biodegradable. 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.
However, conventional MnO2 electrode preparation methods incur high costs, and complicated processes could result in agglomeration of the MnO2 ink during the coating process, leading to the reduction of electrical conductivity.
Instead, researchers from the Hong Kong Polytechnic University developed a simple approach to synthesize aqueous MnO2 ink. They first coated the MnO2 ink on conductive A4 paper and fabricated a capacitive energy storage device with maximum energy density and power density amounting to 4 mWh/cm3 and 13 W/cm3, respectively.
The MnO2 ink capacitor had a capacity more than 30 times higher than that of a commercial capacitor of the same weight of active material (e.g. carbon powder), demonstrating the potential of MnO2 ink in enhancing the performance of energy storage devices.
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.
In wearable devices and radio-frequency identification systems, the MnO2 ink supercapacitor could be used as the power sources for the flexible and “bendable” display panels, smart textile, smart checkout tags, sensors, luggage tracking tags, etc., thereby contributing to the further development of these two areas.
The research team is working to further improve the performance of the MnO2 ink energy storage device, with special focus on increasing the voltage, optimizing the structure and synthesis process of the device. In addition, further tests will be conducted to integrate the MnO2 ink energy storage device with other energy collection systems.
The article can be found at: Qian et al. (2015) Aqueous Manganese Dioxide Ink for Paper-Based Capacitive Energy Storage Devices.
Source: The Hong Kong Polytechnic University.
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