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Farjand
Farjand • Jul 25, 2011

Transparent batteries: Stanford Scientists Look Through Future

Powerful batteries are of course in demand in market and the demand is been ably supplied commercially by Lithium batteries but what if we can also make it look more beautiful? This could be a selling point of the new batteries may be in luxury cars. Perhaps keeping the same thing in mind, research student from Stanford University Yuan Yang and his Yi Cui associate professor of materials science and engineering at SLAC National Accelerator Laboratory have devised a transparent Lithium ion battery to power future generation gadgets. The team also included Sangmoo Jeong, Liangbing Hu, Hui Wu and Seok Woo Lee of Stanford University.

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Yuan Yang, a graduate student in Materials Science, holds one of the transparent batteries he developed with Professor Yi Cui.

Considering the basic components of conventional batteries, it is actually highly impossible to make copper or aluminum invisible. The researchers hence tried to fool human eyes by making materials so small that human eyes could not resolve it and the man watching it believes that the batteries are invisible. The researchers have explained the science behind this in their research paper submitted in Proceedings of the National Academy of sciences.

However making the battery constituents tiny is actually a tough task in other words, "it is easier said than done". The scientists hence had to find a suitable alternative to satisfy two conditions; the first one being, the material should be transparent and the other being it should be conductive too. In this study, Yang and Cui found potential in a material commonly used to make object visible! The material is polydimethylsiloxane or PDMS. The rubbery compound finds wide applications in production of contact lenses and plastic surgery. The only limitation here was that PDMS is not conductive and hence not useful for battery. The researchers hence resorted to make it conductive by pouring it into silicon molds and to create a grid pattern out of it. Next the grid pattern was subjected to vapors of metal to deposit a metal film on the constructed grid.

Check out the following video -



In the next step, scientists poured a liquid solution of nano sized electrodes in to the grid trenches.  Yang also modified a gel electrolyte to make it serve both as a separator and an electrolyte. It was then sandwiched in the electrodes. The researchers created multiple layers of battery; each one consisting of an electrolyte layer placed between two electrodes.

The transparency of the battery depends on an individual's resolving power of eye. A normal human eye can see an object as tiny as 50 microns. Each line in a grid is so finely spaced that each line is less than 50 microns. The transmittance tests conducted by Yang and Cui showed that the battery grid is 62% invisible when subjected to visible light. On the other hand only a minute invisibility loss was experienced when three full cells were stacked on top of each other. In latter case the transparency was found to be 60%. The entire structure of battery was also found to be flexible than the conventional one.

Speaking of the power produced by the new energy source, the researchers said that it was half that of the lithium based batteries. Efforts are on to increase its capacity too. The transparent battery also exposes the fashion angle or the artistic approach of the serious engineering trade.

Source: Stanford University

 

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