Michigan Tech Scientist's Discovery Could Lead to a Better Capacitor
http://www.mtu.edu/news/stories/2013/april/story88254.html[font face=Serif][font size=5]Michigan Tech Scientist's Discovery Could Lead to a Better Capacitor[/font]
Last Modified 1:30 PM, April 18, 2013
The non-aligned manganese dioxide nanorods on the left were made using conventional methods. The aligned nanorods on the right were grown in Dennis Desheng Meng's lab using electrophoretic deposition. Photos by Sunand Santhanagopalan
[font size=3]April 16, 2013A new process for growing forests of manganese dioxide nanorods may lead to the next generation of high-performance capacitors.
As an energy-storage material for batteries and capacitors, manganese dioxide has a lot going for it: its cheap, environmentally friendly and abundant. However, chemical capacitors made with manganese dioxide have lacked the power of the typical carbon-based physical capacitor. Michigan Technological University scientist Dennis Desheng Meng theorized that the situation could be improved if the manganese dioxide were made into nanorods, which are like nanotubes, only solid instead of hollow. However, a stumbling block has been making manganese dioxide nanorods with the right set of attributes. Until now, researchers have been able to grow nanorods that either have the best crystalline structure or were aligned, but not both.
Now, Mengs research group has developed a technique to grow manganese dioxide nanorods that are not only straight and tall (at least by nano-standards), but also have the optimal crystal structure, known as ?-MnO[font size="1"]
2[/font].
This minimizes the internal resistance, allowing the capacitor to charge and discharge repeatedly without wearing out. Thats a recipe for a better capacitor: it can store more energy, extract that energy more quickly, and work longer between rechargings. Plus, it can be used over and over again. Even after Mengs group recharged their capacitor more than 2,000 times, it was still able to regain over 90 percent of its original charge.
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