Nano coatings show big potential for energy storage
Sitting in his office, Sitting in his office, Professor Marc Anderson picks up a small vial of clear liquid and shines a laser pointer through it. A deep green line bisects the vial, evidence of nanoparticles suspended in the liquid.
This liquid is Anderson’s platform technology. With it, he can dip or spray oxide-based nanoparticle coatings on virtually any surface for applications ranging from air and water purification to corrosion resistance. The technology has yielded both licensing agreements and startup companies.
One such company is SolRayo, which Anderson and PhD student Kevin Leonard founded in 2007 to develop ultra-capacitors for renewable-energy storage.
“If you could couple batteries with ultra-capacitors, instead of having a two-year-life device, you could have a 10- to 20-year device,” says Leonard.
While conventional chemical batteries wear out after hundreds of charges, ultracapacitors use ions to store energy and can charge and discharge hundreds of thousands of times. “We actually have done 3 million discharge cycles on a device in our lab,” says Leonard.
Simply, an ultracapacitor consists of two separate electrodes immersed in a liquid electrolyte. Pairing ions from the electrolyte with the positive or negative electrode, the ultracapacitor stores energy at the electrode-electrolyte interface.
High-surface-area carbon is among the most effective — and expensive — electrode materials, in part, because it is heavily processed to make it extremely porous. As an alternative, Leonard, Anderson and colleagues at SolRayo can coat less-expensive carbon or the high-surface-area carbon with carefully sized nanoparticles. While the latter results in a more costly, high-performance device, SolRayo is focusing on the former option, which could result in larger, less-expensive ultracapacitors.
Using their technology, Leonard and his team have built a quarter-sized ultracapacitor that can hold about 2 farads of charge. Currently, they are working on a proof-of-concept prototype that, at about 18 cubic inches, will hold 3,000 farads.
A subsidiary of California-based Enable IPC Corp., SolRayo received a $250,000 grant in 2008 from the Wisconsin Energy Independence Fund to develop its technology.
Kings of the road
With gleaming stainless-steel equipment, Professor Hussain Bahia’s third-floor Engineering Hall laboratory feels much like a high-tech kitchen. There, he and his students meticulously develop and test “recipes” for asphalt mixes that can help contractors make the most of their material.
Among their ingredients are polymer additives developed by Honeywell Specialty Additives of Morristown, New Jersey, and premiered in Wisconsin. Modified asphalts — those mixed with various additives — can increase pavement resistance to damage such as wheel-path rutting or cracking.
Through a collaboration with Honeywell, Bahia and his students helped the company select its polymers, which provide a much-needed alternative for such additives. In 2008, a competing polymer experienced a nation-wide shortage. As a result, many departments of transportation had to revise bids because the polymer wasn’t available. “I think it’s a good thing to have Honeywell develop polymers that are comparable to polymers on the market to ensure there’s adequate supply and competitive pricing,” says Wisconsin Asphalt Pavement Association Executive Director Scot Schwandt, who introduces association members to new asphalt products and processes.
Mixed according to specifications, the Honeywell polymers — sold as Honeywell Titan — can help contractors save time and money. Other polymer additives are mixed with asphalt off-site and transported in large tankers to a contractor’s facility. However, contractors can blend the Honeywell Titan polymers in-house, enabling them to mix only the amount of asphalt they need for any size project. The additives also may offer contractors the freedom to work in winter. “If these polymers prove good for low-temperature compaction, then we can extend the construction season,” says Bahia.
He and his students are working with the Wisconsin Department of Transportation and Honeywell on ways to certify the polymer incorporation process. They also are testing the modified asphalts in the lab and on the road, so that all stakeholders can feel confident about them. “We expect it to be a much better opportunity for the contractors, as well as the public, because eventually we can fix more roads than what we are doing right now,” says Bahia.
The future of water, now
Using a leading-edge forecasting method called nowcasting, water resources managers can use real-time data to monitor, evaluate and respond to changes in everything from algae blooms to water levels in the streams, rivers and lakes under their watch.
While forecasts rely on models built with past data, a nowcast draws on current observations and measurements that provide up-to-the minute information. In Madison, researchers have compiled data from 11 U.S. Geological Service gauging stations; an instrument atop the UW-Madison Atmospheric, Oceanic and Space Science Building; an oceanographic research buoy on Lake Mendota; and user-generated information from the website Weather Underground to create INFOS (www.infosyahara.org), the integrated nowcast/forecast operation system for Yahara Lakes.
Developed by a multidisciplinary, multi-university team of researchers led by Professor Chin Wu, INFOS combines real-time weather and water data to help Madison, Dane County and the Wisconsin Department of Natural Resources regulate water levels, monitor and restore wetlands, evaluate weed growth and cutting practices, and warn of algae blooms in the five-lake Yahara chain.
With $1.35 million from the National Science Foundation, Wu created the real-time system in part because he feels using past data to predict the future is a flawed approach. Currently, INFOS centers primarily around the two largest lakes, Mendota and Monona; however, Wu expects that within three years, it will provide comprehensive data about each body of water in the Yahara chain.
Because INFOS operates on an open-source, plug-and-play concept, water managers worldwide can adapt it. On Lake Superior, for example, researchers funded through the UW Sea Grant Institute are using a similar model to study wave swells in real time. “We’d like to share this so that other people can use it, so that the system is a benefit to society,” says Wu.
His collaborators include PhD student John Reimer, UW-Madison Center for Limnology Associate Scientist Paul Hanson, Computer Sciences Professor Miron Livny and Associate Professor An Hai Doan, Binghamton University Computer Science Assistant Professor Kenneth Chiu, and University of Western Australia Earth and Environment Research Assistant Professor Matt Hipsey.