Oct
29
New Process For a Silicon Anode in Lithium Batteries
October 29, 2015 | Leave a Comment
University of Waterloo researchers have developed an innovative technology using silicon to improve lithium-ion battery anodes. Zhongwei Chen, a chemical engineering professor at Waterloo, and a team of graduate students have created a low-cost battery using silicon that boosts the performance and life of lithium-ion batteries. Substantially smaller and longer-lasting batteries for everything from portable electronic devices to electric cars could be come a reality now.
The Waterloo team’s findings have been published in the latest issue of Nature Communications.
Current lithium-ion batteries normally use graphite anodes. The Waterloo engineers found that silicon anode materials have a much higher capacity for lithium and are capable of producing batteries with almost 10 times more energy.
Professor Chen, the Canada Research Chair in Advanced Materials for Clean Energy and a member of the Waterloo Institute for Nanotechnology and the Waterloo Institute for Sustainable Energy said, “Graphite has long been used to build the negative electrodes in lithium-ion batteries. But as batteries improve, graphite is slowly becoming a performance bottleneck because of the limited amount of energy that it can store.”
(a) Components mixing under ultrasonic irradiation, (b) an optical image of the as-fabricated electrode made of SiNP, SG and PAN, (c) the electrode after SHT, (d) Schematic of the atomic scale structure of the electrode. For more information and a full size view click the link to the Nature Communications study link above.
The most critical challenge the researchers faced when they began producing batteries using silicon was the loss of energy that occurs when silicon contracts and then expands by as much as 300 percent with each charge cycle. The resulting increase and decrease in silicon volume forms cracks that reduce battery performance, create short circuits, and eventually cause the battery to stop operating.
To overcome this problem, Professor Chen’s team along with the General Motors Global Research and Development Center developed a flash heat treatment for fabricated silicon-based lithium-ion electrodes that minimizes volume expansion while boosting the performance and cycle capability of lithium-ion batteries.
Professor Chen explains, “The economical flash heat treatment creates uniquely structured silicon anode materials that deliver extended cycle life to more than 2000 cycles with increased energy capacity of the battery.”
The Waterloo silicon battery technology promises a 40 to 60 percent increase in energy density, which is important for consumers with smartphones, smart homes and smart wearables.
The environmentally safe technology could also make dramatic improvements for hybrid and electric vehicles. The findings could mean an electric car may be driven up to 500 kilometers between charges and the smaller, lighter batteries may significantly reduce the overall weight of vehicles.
Professor Chen expects to commercialize this technology and expects to see new batteries on the market within the next year.
Perhaps Chen is right. With General Motors backing the research with cash and resources plus a ready market for their automobiles, a huge increase in range would be a very powerful incentive to get the technology right and on the market as quickly as possible. 500 km is about 300 miles. That just might breakout the electric car market into the mainstream.
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