VCU researcher receives NSF grant to extend lifespan of Li-ion batteries, make them more environmentally friendly

Arunkumar Subramanian, Ph.D., an assistant professor in the Department of Mechanical and Nuclear Engineering in the School of Engineering, will use the grant to deliver technological advances that reduce the cost and carbon footprint of Li-ion batteries by extending their lifespan.

A Virginia Commonwealth University professor has received a five-year, $505,000 award from the National Science Foundation to make lithium-ion batteries — which power electric vehicles and portable electronic devices — far more efficient, sustainable and environmentally friendly.

Arunkumar Subramanian, Ph.D., an assistant professor in the Department of Mechanical and Nuclear Engineering in the School of Engineering, will use the grant to deliver technological advances that reduce the cost and carbon footprint of Li-ion batteries by extending their lifespan. He will simultaneously research alternative battery materials that are both nontoxic and more abundant.

"If you look at electrical energy storage solutions that are used in today's electric vehicles and portable electronic devices, you would find that lithium-ion batteries is the technology of choice," Subramanian said. "But if you want to make this technology truly sustainable and environmentally benign, then we need to be able to reduce its cost, as well as its carbon footprint as compared to energy derived from other sources such as fossil fuels."

Subramanian plans to address these goals by extending the lifespan of Li-ion batteries made from sustainable electrode materials, which are derived from the nontoxic manganese oxide material system.

“This project is likely to result in transformative innovations for the battery industry, which in turn will impact a whole host of consumer devices and cars.”

"This project is likely to result in transformative innovations for the battery industry, which in turn will impact a whole host of consumer devices and cars," said Ram Gupta, Ph.D., a professor and associate dean for research in the School of Engineering.

An overarching goal of the project, "Sustainable Solutions for Li-ion Batteries through Cycle-Life Improvements in Nanostructured, 'Green' Cathodes," is to maximize the environmental benefits of electric cars.

"Electric vehicles are one alternative for reducing fossil fuel consumption and greenhouse gas production for sustainable transportation needs," according to the project's abstract. "Electric vehicles require rechargeable batteries that balance the electrical energy storage and power delivery needs, and these batteries must have a lifespan sufficient to reduce cost and achieve true carbon footprint reduction. Furthermore, batteries should be manufactured from sustainable materials to minimize environmental impact."

The award is from National Science Foundation's Faculty Early Career Development (CAREER) Program, which provides the foundation's most prestigious awards in support of junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of education and research within the context of the mission of their organizations.

A key aspect of Subramanian's project will be to create batteries in which the team will isolate a single manganese oxide nanowire as the battery's functional electrode element. These nanowire materials are synthesized and supplied by Ekaterina Pomerantseva, Ph.D., a research collaborator and materials science professor at Drexel University.

"Now, the reason we want to do this with nanomaterials is because the small form-factors have the potential to facilitate high charge-storage capacities at fast battery charging and discharging rates,” Subramanian said. “The use of a single nanowire battery electrode is motivated by its ability to reveal the electrochemically correlated structure-property-performance relationships in the material system with atomic-to-nanoscale scale resolution, thereby enabling the optimization of the host crystal to lithium intercalation."

The "nanowires" are one-dimensional constructs that have a diameter of roughly 10 nanometers to 20 nanometers. A nanometer is one billionth of a meter.

"If you were to compare these nanowires to, say, a human hair, [the hair would be] about 10,000 times larger than these nanowires in diameter," Subramanian said.

“If you were to compare these nanowires to, say, a human hair, [the hair would be] about 10,000 times larger than these nanowires in diameter.”

These nanowire electrodes will be tested using a co-integrated device created on silicon chips, which includes a lithium cell and a nanoelectromechanical resonator for charge capacity measurements. The functional components of this device are contained within an ultra-small footprint of a square micron, representing the current state-of-the-art for nanosystems made from synthetic constructs.

Much of the testing with the devices is being conducted at Nanomaterials Core Characterization Facility, a research core facility of the VCU Office of Research and located in the Institute for Engineering and Medicine.

As part of the project, Subramanian's team will also develop a "nano energy" workshop for high school teachers taking part in the NanoFellows Institute organized by the MathScience Innovation Center in Richmond.

"We'll have the teachers visit our lab and do hands-on experiments with nano-enabled batteries and then they would take some of these samples for demonstrations in their classrooms during the school year," he said.

The researchers will also implement "nanobot" workshops and summer research internship programs, which are focused on the use of nanorobots inside electron microscopes, targeting Summer Regional Governor’s School student participants at the MathScience Innovation Center.

The researchers will also introduce this "nano energy" module to high school students taking part in the Richmond Area Program for Minorities in Engineering, a nonprofit organization that works to increase diversity in science and engineering.

Source: VCU

Defects in solar cells made of silicon identified

Sergio Castellanos wants continue researching, work in an industry and does not rule out to eventually move to another country. Credit: Image courtesy of Investigación y Desarrollo

Since he was a teenager, engineer Sergio Castellanos had the desire to study abroad to prepare and do research in the best laboratories, particularly on solar energy. With six years of stay in the United States, first at the University of Arizona and now at the Massachusetts Institute of Technology (MIT) in Boston, his dream has come true:

"Working on defects found on silicon and their impact on the efficiency of solar cells made with this material."

This research is carried out to obtain his doctorate from MIT.

"Dislocation is a defect that occurs at high temperatures, of 500 ° C onwards. In my research I analyze these defects and their impact on the efficiency of solar cells made from silicon, since this material is used in over 90 percent of solar panels worldwide ."

The Mexican researcher in Boston explains that the harmful part of the dislocation is interacting with other defects such as metallic impurities within the material of solar cells; they tend to reduce efficiency by -for example- interacting with electrons.

"When having a dislocation is very easy for impurities to settle into a defect in the material. Therefore, in my research I analyze at an early scale what kind of dislocations will be more harmful to the cells, meaning, which ones will interact more with impurities because not all do likewise, hence not all dislocations are equally harmful."

The proposal of Sergio Castellanos at the MIT is to apply a method in wafers of polycrystalline silicon before being processed into solar cells. This method involves using a chemical treatment in order to view the dislocations and analyze the geometric variation on the surface. After making crystallographic analysis as well as X-rays for determining the distribution and concentration of metal impurities, a correlation is made with the geometric appearance of the surface and then, just by looking at the surface, one can deduce what the electrical behavior within material will be.

"The goal is to identify which areas of the material will be more likely for electrons to recombine before being extracted by contacts, becoming less efficient cells."

A little bit of history

When the native of Hermosillo, Sonora (northern state of Mexico), was in high school, he applied for the Massachusetts Institute of Technology (MIT) and was not admitted. He told himself he would not be discouraged because surely the opportunity would could come later. He decided to study mechanical engineering at the Technological Institute of Hermosillo and two years in his parents supported him to finish his degree abroad.

He was transferred to the University of Arizona where he finished his degree. At the university, he became involved in several projects on the subject of energy, as was the case with hydrogen cells, a solar car and installing solar panels.

The Mexican says he enjoyed doing research and started looking for projects and teachers who worked in that area. He spotted four scientists, but wanted to go to MIT because "for any engineer to be in this school is a dream. I had practice in energy research during my bachelor's and for my doctorate I looked for subjects in this area. I applied at several universities and at last I was admitted at MIT in Boston."

His research in solar cells is in the last stage, and once completed in the next year he will make it available to other researchers. This work was presented at various conferences and has received good reviews in terms of utility.

To "finish the tale" on solar cells, the Mexican will complete his studies in six to eight months, and is more than satisfied with the subject that has developed during his research.

Sergio Castellanos wants continue researching, work in an industry and does not rule out to eventually move to another country. In the remaining months he will define his next step. (Agencia ID)

Source: Investigación y Desarrollo

Easy measurement of the effect of fine dust

The Karlsruhe Exposure System is compact and can measure fine dust concentrations directly at the location of pollution. Credit: VITROCELL Systems GmbH

Fine dusts from industry, traffic, and households are omnipresent. Still, they are difficult to capture by reliable medical measurements. KIT researchers have now developed an exposure system, by means of which biological cells are exposed to fine dust-loaded air flows in an exact and reproducible manner. Using this system, it is possible to collect data on the adverse impact of fine dusts of variable sources in a rapid and inexpensive manner and without animal experiments being needed. In cooperation with the industry partner Vitrocell, a marketable product has been developed.

"Fine dusts may be carbon black from diesel engines, sea salt on the coast, natural dusts, or intermediate products of chemical industry," Dr. Hanns-Rudolf Paur and Sonja Mülhopt of Karlsruhe Institute of Technology explain. All dust grains smaller than 10 µm, i.e. one hundredth of a millimeter, are considered to be fine dust irrespective of their chemical composition. Dust particles smaller than 10 µm easily pass the upper respiratory tract of man. "They deposit in the pulmonary alveoli and may damage the lungs due to their chemical or physical properties."

To study the effects in detail, lung cells and fine dust have to be brought together in a realistic environment. Ultimately, the processes taking place in the human body from the nose to the lungs have to be reproduced. For this purpose, the air containing the fine dust is heated up to body temperature by the Karlsruhe Exposure System. The air flow is provided with about 85% humidity and reduced to the air flow rate of the lungs. For a long-term measurement series, these conditions have to be maintained exactly and reproducibly. Finally, the particle flow passes lung cell cultures cultivated with nutrient medium. 

Depending on the type of fine dust, these cultures subsequently show symptoms of inflammation, oxidation stress, or membrane damage. In parallel, the deposited particle dose is recorded by means of a precision balance.

The new Exposure System is much closer to reality than previous methods that collected fine dust from air or exhaust gas and stirred it into the nutrient liquid. At the same time, the Exposure System works more rapidly for many applications and is cheaper than a study based on animal experiments. Thanks to its compactness, the Karlsruhe Exposure System can also be used for measurements at the place of fine dust development or pollution. "The limitations of conventional methods were overcome by the close, interdisciplinary cooperation of biologists and process engineers at KIT," the Head of the project, Sonja Mülhopt, says. "With the Karlsruhe Exposure System, we now have a technology that will improve the protection of the environment and mankind."

"Research at KIT was the basis of a process with a high industry potential," Tobias Krebs of the company Vitrocell Systems (Waldkirch) says. "Together, we now plan to commercialize this product." The impact of fine dusts plays an important role in fundamental research as well as in many areas of application. According to the EU Directive on Chemicals REACH, chemical industry is obliged to classify its products in various hazard categories. 

Manufacturers of lung medicine, such as asthma sprays, are now enabled to test new substances in a close-to-reality manner. New and old biomass fuels may also be relevant fine dust sources.

Source:  Karlsruhe Institute of Technology

Switching to vehicles powered by electricity from renewables could save lives

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. Credit: © Dmitry Vereshchagin / Fotolia

Driving vehicles that use electricity from renewable energy instead of gasoline could reduce the resulting deaths due to air pollution by 70 percent. This finding comes from a new life cycle analysis of conventional and alternative vehicles and their air pollution-related public health impacts, published Monday, Dec. 15, 2014, in the Proceedings of the National Academy of Sciences.

The study also shows that switching to vehicles powered by electricity made using natural gas yields large health benefits. Conversely, vehicles running on corn ethanol or vehicles powered by coal-based or "grid average" electricity are worse for health; switching from gasoline to those fuels would increase the number of resulting deaths due to air pollution by 80 percent or more.

"These findings demonstrate the importance of clean electricity, such as from natural gas or renewables, in substantially reducing the negative health impacts of transportation," said Chris Tessum, co-author on the study and a researcher in the Department of Civil, Environmental, and Geo- Engineering in the University of Minnesota's College of Science and Engineering.

The University of Minnesota team estimated how concentrations of two important pollutants -- particulate matter and ground-level ozone -- change as a result of using various options for powering vehicles. Air pollution is the largest environmental health hazard in the U.S., in total killing more than 100,000 people per year. Air pollution increases rates of heart attack, stroke, and respiratory disease.

The authors looked at liquid biofuels, diesel, compressed natural gas, and electricity from a range of conventional and renewable sources. Their analysis included not only the pollution from vehicles, but also emissions generated during production of the fuels or electricity that power them. With ethanol, for example, air pollution is released from tractors on farms, from soils after fertilizers are applied, and to supply the energy for fermenting and distilling corn into ethanol.

"Our work highlights the importance of looking at the full life cycle of energy production and use, not just at what comes out of tailpipes," said Bioproducts and Biosystems Engineering Assistant Professor Jason Hill, co-author of the study. "We greatly underestimate transportation's impacts on air quality if we ignore the upstream emissions from producing fuels or electricity."

The researchers also point out that whereas recent studies on life cycle environmental impacts of transportation have focused mainly on greenhouse gas emissions, it is also important to consider air pollution and health. Their study provides a unique look at where life cycle emissions occur, how they move in the environment, and where people breathe that pollution. Their results provide unprecedented detail on the air quality-related health impacts of transportation fuel production and use.

"Air pollution has enormous health impacts, including increasing death rates across the U.S.," said Civil, Environmental and Geo- Engineering Associate Professor Julian Marshall, co-author on this study. "This study provides valuable new information on how some transportation options would improve or worsen those health impacts."

Source: University of Minnesota

The Matched 'hybrid' systems may hold key to wider use of renewable energy

Wind farms such as this one in Idaho might be combined with other forms of alternative energy to better balance the output of sustainable energy. Credit: Nordex USA/US Department of Energy

The use of renewable energy in the United States could take a significant leap forward with improved storage technologies or more efforts to "match" different forms of alternative energy systems that provide an overall more steady flow of electricity, researchers say in a new report.

Historically, a major drawback to the use and cost-effectiveness of alternative energy systems has been that they are too variable -- if the wind doesn't blow or the sun doesn't shine, a completely different energy system has to be available to pick up the slack. This lack of dependability is costly and inefficient.

But in an analysis just published in The Electricity Journal, scientists say that much of this problem could be addressed with enhanced energy storage technology or by developing "hybrid" systems in which, on a broader geographic scale, one form of renewable energy is ramping up even while the other is declining.

"Wind energy is already pretty cost-competitive and solar energy is quickly getting there," said Anna Kelly, a graduate student in the School of Public Policy at Oregon State University, and an energy policy analyst. "The key to greater use of these and other technologies is to match them in smart-grid, connected systems.

"This is already being done successfully in a number of countries and the approach could be expanded."

For instance, the wind often blows more strongly at night in some regions, Kelly said, and solar technology can only produce energy during the day. By making more sophisticated use of that basic concept in a connected grid, and pairing it with more advanced forms of energy storage, the door could be opened for a much wider use of renewable energy systems, scientists say.

"This is more than just an idea, it's a working reality in energy facilities around the world, in places like Spain, Morocco and China, as well as the U.S.," Kelly said. "Geothermal is being paired with solar; wind and solar with lithium-ion batteries; and wind and biodiesel with batteries. By helping to address the price issue, renewable energy is being produced in hybrid systems by real, private companies that are making real money."

Advanced energy storage could be another huge key to making renewable energy more functional, and one example is just being developed in several cooperating states in the West. Electricity is being produced by efficient wind farms in Wyoming; transmitted to Utah where it's being stored via compressed air in certain rock formations; and ultimately used to help power Los Angeles.

This $8 billion system could be an indicator of things to come, since compressed air can rapidly respond to energy needs and be readily scaled up to be cost-competitive at a significant commercial level.

"There are still a number of obstacles to overcome," said Joshua Merritt, a co-author on the report and also a graduate student in mechanical engineering and public policy at OSU. "Our transmission grids need major improvements so we can more easily produce energy and then send it to where it's needed. There are some regulatory hurdles to overcome. And the public has to more readily accept energy systems like wind, wave or solar in practice, not just in theory."

The "not in my back yard" opposition to renewable energy systems is still a reality, the researchers said, and there are still some environmental concerns about virtually any form of energy, whether it's birds killed by wind turbine rotors, fish losses in hydroelectric dams or chemical contaminants from use of solar energy.

The near future may offer more options, the researchers said. Advanced battery storage technologies are becoming more feasible. Wave or tidal energy may become a real contributor, and some of those forces are more predictable and stable by definition. And the birth of small, modular nuclear reactors -- which can be built at lower cost and produce no greenhouse gas emissions -- could play a significant role in helping to balance energy outflows from renewable sources.

The long-term goal, the report concluded, is to identify technologies that can work in a hybrid system that offers consistency, dependability and doesn't rely on fossil fuels. With careful matching of systems, improved transmission abilities and some new technological advances, that goal may be closer than realized, they said.

"With development, the cost of these hybrid systems will decrease and become increasingly competitive, hopefully playing a larger role in power generation in the future," the researchers wrote in their conclusion.

Source: Oregon State University