Posted on 08/03/2011 12:16:01 AM PDT by neverdem
Energy-harvesting windows are a step closer with the development of a transparent lithium ion battery, created by US researchers at Stanford University. The electrodes are confined to a grid 35µm wide, making them too narrow to be perceived by the naked eye.
The electrodes pose the biggest challenge to transparent lithium ion batteries, as both anode and cathode materials are typically opaque. Yi Cui's team solved this problem by making them very thin. They set the electrode materials into a grid of trenches in clear polydimethylsiloxane (PDMS). By stacking and aligning the grids with additional layers of electrodes, it is possible to increase the battery's energy storage without sacrificing its transparency.
The Stanford team deposited a 100nm thick gold layer onto the PDMS to collect the current generated. The researchers took advantage of capillary action to pull slurries of water and electrode material - LiMn2O4 nanorods for the cathode and Li4Ti5O12 nanopowder for the anode - through the grids to create the battery's structure.
|
By producing extremely fine electrodes researchers were able to produce transparent batteries
© Proc. Natl Acad. Sci. USA
|
The team then sandwiched a layer of clear electrolyte between the two electrodes, aligning the grids by hand under an optical microscope. Finally, the whole device was enclosed in a clear polymer bag, with two strips of aluminium for terminals. By varying the spacing between the trenches, the researchers achieved transparencies of 78, 60 and 30 per cent. These yielded energy densities of 5, 10, and 20 Watt hours per litre (Wh/L), respectively.
Jongseung Yoon, a nanoelectronics expert at the University of Southern California, US, says the team's approach 'is particularly attractive as it is scalable to large areas as well as to multiple device stacks'.
This would allow a thin, energy-storing layer to extend all the way across 'smart windows'. According to Luis Sánchez of the University of Córdoba in Spain, whose team made the first transparent electrode, this would be the chief application for transparent batteries. These devices could be combined with transparent solar cells, which have already been developed, to absorb some of the sun's energy as it passes into a building, storing it during the day so that it can be used for low power consumption lighting after dark.
The 60 per cent transparent battery has about one tenth the energy density of the average smart phone battery, which group leader Yi Cui says can get around 100 Wh/L. 'By simple optimisation and utilisation of industrial approaches, 50 Wh/L is achievable at current stages,' he adds.
With advanced electrode materials, he thinks it may be possible reach 150 Wh/L. And because the transparent design allows chemists to watch the reaction taking place inside the battery, studying new electrodes has never been easier.
Y Yang et al, Proc. Natl Acad. Sci. USA, 2011, DOI:10.1073/pnas.1102873108
_tcm18-109278.jpg)
There would still be a bill. Roads would still need to be mailtained and you’d have to pay a much higher wage for people who can fix that road.
But overall, it’s possible that the overall costs could be lower.
Your estimate is low.
Note that these are average values from the entire year. Peaks are far higher. Click pic to enlarge.
Technology sometimes catches up with itself.
I think my wife gets that sometimes. I just try to avoid her for a few days.
oh yeah, that’s the double dose.
While my estimate was “back of the envelope” your map is for a “Two-Axis Tracking Concentrator”. Windows don't track the sun. They don't concentrate the sun's energy. Without tracking, and without even optimal South-facing orientation, my estimate is probably generous. Only one quarter of the windows on a simplified home are South-facing. They will only be roughly oriented toward the sun in the morning and late in the afternoon when light passing through the atmosphere obliquely has already lost much of its energy to atmospheric absorption.
Bottom line: My estimate is high. Take the mid-range of idealized tracking concentrators (these are reflecting windows, not concentrator), 5 KWHrs for about 6 hours giving about 800 watts M-squared (hardly ever happens, but let's use it) divided by 4, assuming a South-facing wall, and, divided by 3 again since less than 2 hours of the 6 are directly incident, giving us about 260 watts, using the cosine of the angle between the sun's elevation to the perpendicular to the window brings you to 130 watts. Then, the reality of atmospheric absorption at low angles, which absorb about half the energy for modest atmospheric water content will bring the real energy available for conversion to electricity to about 65 Watts. Assume ten percent conversion efficiency, which is probably fair - 6.5 watts per square meter.
Without tracking there is little point. But perhaps we could provide tax incentives, or even have the EPA require that all future houses be mounted on gimbals allowing one wall with windows to be moved so to track the sun and our problem is solved!
I had to go through these details to be dissuaded from my idealistic notion of renewable solar energy while in graduate school. I also came to recognize the sad reality of research guided by the latest darling of the political class. Government funding of scientific research has helped to hinder legitimate research in many areas. Just look at climate science. Medicine is a mess. Look at Aids research, and the wonder discovery of the month, which is never heard from again, funded by our tax dollars. Cary Mullis, Nobel for PCR used to detect real virus, discovered that he could be paid for not lecturing about the truth - there is no evidence of a causal relationship between HIV and Aids. But we spend over ten billion a year to keep biochemists busy on what is very likely a wild goose chase. Politicians get plenty of support for their re-election campaigns, and for their compassion. Renewable energy is as good a scam as Aids research, and perhaps better if the can ram cap-and-trade down the throats of the gullible.
The materials science technology does look interesting, but its application is almost worthless. Now if the technology could be used for remote highway emergency phones, or for some other low power, high value application, it could make sense. But as our government's economy is being destroyed our radical left, universities will write proposals the radicals might approve so our grad students have some funding.
Our scientists and engineers are moving back to the countries some of them escaped, and from which some immigrated, Russia, China. I'm urging my children to learn Mandarin or Spanish (Chile), or French (Canada). Those in charge are destroying capitalism by having so many working in the nonproductive sector - government, and so many not working at all. There is no way to support so many non-workers, and no reason to swear allegiance to a country where individual rights are no longer protected by a Constitution.
Like, you hurl coffee or juice at your cat sitting in the window?
More like, it likes laying where you’re guarenteed to trip over it.
Wow, first time in a long time I’ve read about Windows technology I could get energized about. :-/
No buy.
"A light generating device utilizes a large centrally located magnet which is mounted to slide past a magnet pickup or current induction wire which may be preferably mounted at a center point of travel in a tubular housing having a tubular chamber through which the magnet travels. A pair of elastomeric bumpers are located each at the end of the tubular chamber which may be inside or outside the flashlight. The result is a device which both facilitates the manual movement of the flashlight body so that the magnet slides past the center magnet pickup or current induction wire, and also conserves the residual momentum of the magnet once it has traveled past the magnet pickup or current induction wire by providing a bumper and spring to conserve some of the mechanical energy going in the other direction. Ninety second of manual activation enables about five minutes of illumination. "
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.