The Electrochemical Society is a learned society based in the United States that supports scientific inquiry in the field of electrochemistry and solid-state science and technology. ECS bridges the gaps among academia, research, and engineering – bringing together scientists from around the world for the exchange of technical information.The Society currently has more than 8,000 scientists and engineers in over 70 countries worldwide who hold individual membership, as well as roughly 100 corporations and laboratories that hold corporate membership. Wikipedia.
News Article | April 19, 2017
Carbon steel, an alloy made from iron and carbon, is the single largest class of alloys in use today. It's used to make a range of products from fences and springs to steel wires and pipelines, and for structural support in buildings, bridges, as well as nuclear power and fossil fuel power plants. The corrosion of carbon steel, however, is a huge cost to industry and is of enormous practical importance. One common corrosion inhibitor used in the construction industry, calcium nitrite, is quite toxic to humans, impairing the ability of red blood cells to transport oxygen. Seeking safer corrosion inhibitors, Yong Teck Tan and colleagues from the National University of Singapore and Singapore Institute of Manufacturing Technology investigated molybdate as a potential alternative and developed a technique to determine its suitability. Molybdate is non-toxic, and protects the carbon steel from corrosion by competitive adsorption against chloride on the passive film surface, and, in the presence of calcium cations, can also deposit a layer of calcium molybdate. "Our aim was to first determine the suitability of molybdate as a corrosion inhibitor for carbon steel in alkaline environments, and then to investigate its effect on the passivation of carbon steel," says Tan. "Previous studies using electrochemical techniques have focused on corrosion inhibition efficiency at a particular time, which provides a snapshot of the level of corrosion at that instant," explains Tan. "Depending on whether it was assessed over short or long timescales, different conclusions were drawn." So the research team took a longer look. They used an electrochemical method for estimating the extent of corrosion over the entire duration of the investigation, and could assess the overall effectiveness of molybdate. "Even though molybdate resulted in a slightly higher passive current in the later stages, faster passivation in the early stages resulted in a lower overall level of corrosion," says Tan. The researchers found that incomplete coverage of the carbon steel by the calcium molybdate led to slightly higher corrosion rates compared with untreated surfaces. By controlling the composition of the molybdate solution, however, the calcium molybdate film covered the entire surface, resulting in improved corrosion resistance. "Overall, molybdate proved to be an effective corrosion inhibitor," says Tan. "We will now explore its effectiveness in solutions containing other ions." Explore further: Improved corrosion protection with flake-type particles of zinc-phosphate More information: Yong Teck Tan et al. Effect of Molybdate on the Passivation of Carbon Steel in Alkaline Solutions under Open-Circuit Conditions, Journal of The Electrochemical Society (2016). DOI: 10.1149/2.0651610jes
News Article | April 26, 2017
When a battery enters "old age," scientists refer to its diminished performance as "capacity fade," in which the amount of charge a battery can supply decreases with repeated use. Capacity fade is the reason why a cell phone battery that used to last a whole day will, after a couple of years, last perhaps only a few hours. But what if scientists could reduce this capacity fade, allowing batteries to age more gracefully? "Now that we know the mechanisms behind the trapping of lithium ions and the capacity fade, we can find methods to solve the problem." Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory identified one of the major culprits in capacity fade of high-energy lithium-ion batteries in a paper published in The Journal of the Electrochemical Society. For a lithium-ion battery – the kind that we use in laptops, smartphones, and plug-in hybrid electric vehicles – the capacity of the battery is tied directly to the amount of lithium ions that can be shuttled back and forth between the two terminals of the battery as it is charged and discharged. This shuttling is enabled by certain transition metal ions, which change oxidation states as lithium ions move in and out of the cathode. However, as the battery is cycled, some of these ions – most notably manganese – get stripped out of the cathode material and end up at the battery's anode. Once near the anode, these metal ions interact with a region of the battery called the solid-electrolyte interphase, which forms because of reactions between the highly reactive anode and the liquid electrolyte that carries the lithium ions back and forth. For every electrolyte molecule that reacts and becomes decomposed in a process called reduction, a lithium ion becomes trapped in the interphase. As more and more lithium gets trapped, the capacity of the battery diminishes. Some molecules in this interphase are incompletely reduced, meaning that they can accept more electrons and tie up even more lithium ions. These molecules are like tinder, awaiting a spark. When the manganese ions become deposited into this interphase they act like a spark igniting the tinder: these ions are efficient at catalyzing reactions with the incompletely reduced molecules, trapping more lithium ions in the process. "There's a strict correlation between the amount of manganese that makes its way to the anode and the amount of lithium that gets trapped," said study coauthor and Argonne scientist Daniel Abraham. "Now that we know the mechanisms behind the trapping of lithium ions and the capacity fade, we can find methods to solve the problem." Explore further: New lithium ion battery strategy offers more energy, longer life cycle More information: James A. Gilbert et al. Transition Metal Dissolution, Ion Migration, Electrocatalytic Reduction and Capacity Loss in Lithium-Ion Full Cells, Journal of The Electrochemical Society (2017). DOI: 10.1149/2.1111702jes
News Article | February 15, 2017
WorldatWork, a nonprofit HR association and compensation authority, is proud to announce that LifeCare has earned WorldatWork’s Seal of Distinction for 2017 for the sixth straight year. The seal is a unique mark of excellence designed to identify organizational success in total rewards effectiveness. LifeCare is one of 160 organizations to be honored as a 2017 recipient. All of the 2017 recipients will be recognized during the WorldatWork Total Rewards Conference & Exhibition, held in Washington, D.C. from May 7-10. “It is an honor to once again receive the AWLP Seal of Distinction,” said Peter Burki, LifeCare Chairman & Chief Executive Officer. “For almost 33 years we have committed ourselves to helping clients, their employees and the employees of LifeCare be successful both in the workplace and at home. We look forward to continuing our support for them as they navigate through their personal needs and life events.” Begun in 2012, the prestigious Seal of Distinction is awarded to companies that meet defined standards of workplace programs, policies and practices weighted on several factors, such as the complexity of implementation, required organizational resources, perceived breadth of access and overall level of commitment from leadership. Applicants are evaluated on: “We congratulate all of the recipients of the 2017 Seal of Distinction. These recipients represent a wide variety of industries from across the U.S. and Canada, showing that the total rewards model applies to employers and employees everywhere,” stated Anne C. Ruddy, president and CEO of WorldatWork. “This year, we saw the highest number of applicants since the Seal of Distinction was created. I’m confident that this means an increasing number of companies are recognizing the importance of a workplace environment that benefits both the employer and employee.” This year’s recipients represent industries of education, finance, government, health, law, manufacturing, and pharmaceuticals – and hail from 36 states, the District of Columbia and Canada. The 2017 list includes 80 companies who are first-time Seal of Distinction recipients. Eighty companies have received the seal in previous years. In addition, 11 organizations, including LifeCare, have qualified every year since WorldatWork started presenting the Seal of Distinction in 2012. LifeCare provides employer-sponsored work-life benefits to 61,000 clients, including Fortune 500 companies and large branches of the federal government, representing 100 million members nationwide. In addition to child and backup care solutions, LifeCare also provides a full suite of work-life solutions that save members time with personal life needs such as: elder care, legal and financial issues, health and everyday responsibilities. LifeCare also operates LifeMart, an online discount shopping website that provides real savings on everyday products and needs. LifeCare is headquartered in Shelton, CT. The Total Rewards Association WorldatWork is a nonprofit human resources association and compensation authority for professionals and organizations focused on compensation, benefits and total rewards. It's our mission to empower professionals to become masters in their fields. We do so by providing thought leadership in total rewards disciplines from the world's most respected experts; ensuring access to timely, relevant content; and fostering an active community of total rewards practitioners and leaders. WorldatWork has more than 70,000 members and subscribers worldwide; more than 80% of Fortune 500 companies employ a WorldatWork member. Founded in 1955, WorldatWork has offices in Scottsdale, Ariz., and Washington, D.C., and is affiliated with more than 70 human resources associations around the world. Below is the complete list of 2017 Seal of Distinction recipients: California ACI Specialty Benefits Actelion Pharmaceuticals US Addepar Foothill Family Fremont Bank Infoblox Inc. Intuit Inc. Los Angeles County Employees Retirement Association (LACERA) Motion Picture Industry Pension & Health Plans Professional Publications Inc. Prologis UCLA Health and David Geffen School of Medicine University of California, Davis University of California, Irvine University of California San Diego District of Columbia Advanced Medical Technology Association American Gas Association DC Water Department of Transportation - Federal Aviation Administration Federal Reserve Board of Governors Financial Industry Regulatory Authority (FINRA) Finnegan, Henderson, Farabow, Garrett & Dunner LLP Hill+Knowlton Strategies Raffa, P.C. Summit Consulting LLC The George Washington University U.S. Citizenship and Immigration Services U.S. Department of Agriculture Florida AACSB International BayCare Health System Black Knight Financial Services, Inc. Broward Health Central Florida Regional Transportation Authority/LYNX Citizens Property Insurance Corporation Seminole State College of Florida Iowa ITA Group, Inc. Principal Financial Group Wells Enterprises Inc. Massachusetts Babson College Bright Horizons Family Solutions Inc. Globoforce Kronos Incorporated Massachusetts Institute of Technology Progress Sunovion Pharmaceuticals Inc. Maryland Bon Secours Health System, Inc. Campbell & Company CareFirst BlueCross BlueShield Continental Realty Corporation Frederick County Public Schools Johns Hopkins University and Health System Marriott International National Institutes of Health National Security Agency Target Community & Educational Services, Inc. Missouri City of Kansas City, Missouri KCP&L Nestle Purina PetCare Co. University of Missouri System Veterans United Home Loans New Jersey BASF Corporation Becton Dickinson CRP Industries Inc. Ferring Pharmaceuticals Inc. KPMG LLP Prudential Financial Sanofi US The Electrochemical Society New York Mastercard Memorial Sloan Kettering Cancer Center MVP Health Care MetLife NYU Langone Medical Center On Deck Capital Inc. Ralph Lauren The YMCA of Greater Rochester North Carolina BlueCross and BlueShield of North Carolina NC State University Orange Water and Sewer Authority (OWASA) RTI International Volvo Group North America Texas Capital Metropolitan Transportation Authority Children's Health City of Southlake Dell Inc. Disability Rights Texas Geokinetics Lloyd's Register Americas Inc. MOGAS Industries, Inc. Ryan, LLC Southwest Research Institute Texas Instruments
News Article | December 13, 2016
Energy storage systems are in demand as never before. Billions of mobile telephones and tablets need electricity to go. Add to this the growing number of electric cars. But, high-performance batteries can also store renewable energy produced by wind turbines and solar cells so that it can be fed into the grid on cloudy and windless days. "Manufacturers of rechargeable batteries are building on the proven lithium-ion technology, which has been deployed in mobile devices like laptops and cell phones for many years," reports TUM researcher Michael Metzger. "However, the challenge of adapting this technology to the demands of electromobility and stationary electric power storage is not trivial." Standard rechargeable batteries are only marginally suited for high performance: "To raise the energy density, you need to increase the voltage or the capacity, and that is where traditional electrode materials and electrolytic fluids reach their limits," explains the physicist. Research is thus running at full pace around the world. For example, engineers are experimenting with special electrode materials that can provide a voltage of nearly 5 volts, instead of the current maximum of 4.2 to 4.3 volts. Consult your engineer about risks and side-effects But this "battery doping" also has side-effects. Changes in the chemical composition of the electrodes and electrolytes can lead to battery performance drops after only a few charging cycles or the formation of gasses at the electrodes that cause the batteries to balloon. "The future of lithium-ion batteries hinges on getting a grip on these undesirable reactions," predicts Metzger. He has already fulfilled one prerequisite to this end: The chemical processes that transpire during charging and discharging can be investigated in detail using the new battery test cell he developed with his team. A test cell for the batteries of the future The researchers spent three years working on their apparatus. "Normally electrolytic fluids and electrodes - the positive cathode and negative anode - are in a permanent electrochemical exchange," says Metzger. "Thus far it has not been possible to investigate the reactions at the anode and cathode independently of each other. We are the first to manage this successfully." The key: The battery test cell, which, like every lithium-ion battery, comprises an anode, a cathode and electrolytes is not completely sealed, but rather is fitted with a fine capillary. This allows gasses that are released during charging and discharging to be sampled and investigated using a mass spectrometer. To study the processes at anodes and cathodes independently of each other, the engineers also modified the membrane - a thin glass ceramic platelet coated with aluminum and synthetics - to make it permeable not only by lithium ions, but also by all other components of the electrolytic fluid. Using their test cell, the researchers were, for the first time, able to explain precisely what transpires inside a high-voltage battery. The results demonstrate that the stability of electrodes and electrolytes depends on several factors, for example, charging voltage, operating temperature and even tiniest chemical impurities: "For industrial end-users, the new measurement methodology is extremely interesting," says Prof. Hubert Gasteiger, who chairs the Department of Technical Electrochemistry. "In our investigations, we were able to show that the development of gasses in batteries can be reduced by adding the right admixtures to the electrolytic fluid or by inhibiting crosstalk between the electrodes." One research result, in particular, bears a direct consequence in practice: The higher the desired voltage, the less residual moisture the materials may contain. Manufacturers could extend the lifetime of future cells by replacing the electrolyte ethylene carbonate with more stable solution components. But here to the devil is in the detail: A small amount of ethylene carbonate is required in current systems to pacify the anode. The new cell allows processes at the anode and the cathode to be observed independently, possibly leading to the discovery of entirely novel solutions. Metzger was recently honored with the Evonik Research Prize for the development of the battery test cell, which, for the first time, allows mass spectroscopy investigations and an independent analysis of the processes at each electrode. The chemical group Evonik awards the prize annually to an exceptional next-generation scientist. Explore further: Could a seawater battery help end our dependence on lithium? More information: Michael Metzger et al, Hydrolysis of Ethylene Carbonate with Water and Hydroxide under Battery Operating Conditions, Journal of The Electrochemical Society (2016). DOI: 10.1149/2.0411607jes Michael Metzger et al. Origin of HEvolution in LIBs: HO Reduction vs. Electrolyte Oxidation, Journal of The Electrochemical Society (2016). DOI: 10.1149/2.1151605jes M. Metzger, P. Walke, B. Strehle, S. Solchenbach, and H. A. Gasteiger: Anodic Oxidation of Carbon and Electrolyte with Different Conducting Salts in High-Voltage Lithium-Ion Batteries Studied By Online Electrochemical Mass Spectrometry; Pacific Rim Meeting on Electrochemical and Solid-State Science, 5. Oct. 2016, ecs.confex.com/ecs/230/webprogram/Paper88604.html
News Article | March 1, 2017
The electrical grid is the central component of energy distribution and consumption, but the control of the same is currently underfunded and incapable of moving the nation toward a clean energy future. In a new study, electrochemical engineering expert Venkat Subramanian discusses the potential for implementing bottom-up renewable grid control with microgrids. Subramanian is a member of The Electrochemical Society and the Washington Research Foundation Innovation Professor of Chemical Engineering and Clean Energy at the University of Washington. “Our hypothesis is that the current grid control method, which is a derivative of traditional grid control approaches, cannot utilize batteries efficiently,” Subramanian says. “In the current microgrid control, batteries are treated as “slaves” and are typically expected to be available to meet only the power needs. This way of optimization will not yield the best possible outcome for batteries.” Microgrids are local energy grids the can disconnect from the traditional grid and operate autonomously. Microgrids have the ability to strengthen and reinforce the traditional grid because they can function even when the main grid is down and are optimal for integrating renewable sources of energy. However, energy storage technology accounts for the highest cost in developing a microgrid, yet is the least understood component and tends to be the most poorly integrated. If batteries and microgrids could interact at a higher efficiency, new possibilities could arise for the future of energy distribution. Subramanian and his team recently published an open access paper in the Journal of The Electrochemical Society, “Direct, Efficient, and Real-Time Simulation of Physics-Based Battery Models for Stand-Alone PV-Battery Microgrids,” describing how microgrids are becoming more widespread and could pave the way for future energy distribution. “In a recently published paper, we show that simulation of the entire microgrid is possible in real-time. We wrote down all of the microgrid equations in mathematical form, including photovoltaic (PV) arrays, PV maximum power point tracking (MPPT) controllers, batteries, and power electronics, and then identified an efficient way to solve them simultaneously with battery models,” Subramanian says. “The proposed approach improves the performance of the overall microgrid system, considering the batteries as collaborators on par with the entire microgrid components. It is our hope that this paper will change the current perception among the grid community.” Subramanian and his team believe that with the right battery and grid control strategies, microgrids could be more efficient and economically feasible. “In our humble opinion, energy and information flow should be bidirectional and a renewable grid should be modeled and controlled simultaneously aiming for the best possible outcomes for all the devices including batteries,” Subramanian says. “This will require strong collaboration between battery and grid modelers, application of nonlinear model predictive control techniques pioneered and championed by chemical engineering and other control communities. Both Pacific Northwest National Laboratory (grid modernization initiative) and the University of Washington have strong leaders in grid control and modeling. We hope to make progress in this topic.”
News Article | January 7, 2016
« UMTRI: average new vehicle fuel economy decreased in 2015 from 2014 | Main | Mobileye and Volkswagen form strategic partnership; real-time image processing for autonomous driving; swarm data » The Electrochemical Society (ECS), in partnership with the Toyota Research Institute of North American (TRINA), a division of Toyota Motor Engineering & Manufacturing North America, Inc. (TEMA), is requesting proposals from young professors and scholars pursuing innovative electrochemical research in green energy technology. The purpose of the annual ECS Toyota Young Investigator Fellowship, established in 2014, is to encourage young professors and scholars to pursue research in green energy technology that may promote the development of next-generation vehicles capable of utilizing alternative fuels. Global development of industry and technology in the 20th century, increased production of vehicles and the growing population have resulted in massive consumption of fossil fuels. Today, the automotive industry faces three challenges regarding environmental and energy issues: Although the demand for oil alternatives—such as natural gas, electricity and hydrogen—may grow, each alternative energy source has its disadvantages. Currently, oil remains the main source of automotive fuel; however, further research and development of alternative energies may bring change. Electrochemical research has already informed the development and improvement of innovative batteries, electrocatalysts, photovoltaics and fuel cells. Through this fellowship, ECS and TRINA hope to see more innovative and unconventional technologies borne from electrochemical research. The fellowship will be awarded to a minimum of one candidate annually. Winners will receive a restricted grant of no less than $50,000 to conduct the research outlined in their proposal within one year. Winners will also receive a one-year complimentary ECS membership as well as the opportunity to present and/or publish their research with ECS. To qualify, a candidate must be under 40 years of age and working in North America. The candidate must submit an original research proposal for review by the ECS Toyota Young Investigator Fellowship Committee. The proposed research theme must not overlap with other research grants or other funded research projects. Depending on the research progress and the results obtained at the completion of the award period, Toyota may elect to enter into a research agreement with the recipient to continue the work. The recipient must publish their findings in a relevant ECS journal and/or present at an ECS meeting within 24 months of the end of the research period. Prof. Patrick Cappillino, University of Massachusetts Dartmouth. Mushroom-derived Natural Products as Flow Battery Electrolytes: to investigate the use of a naturally occurring and biologically produced compound in non-aqueous redox-flow batteries (NRFB) to tune three important attributes while retaining extraordinary metal-binding properties: redox potential; solubility in NRFB solvents; peripheral electrostatic and steric properties. Prof. Yogesh (Yogi) Surendranath, Massachusetts Institute of Technology. Methanol Electrosynthesis at Carbon-Supported Molecular Active Sites: to synthesize a selective electrocatalyst for methane to methanol conversion by ligating single site transition metal compounds known to activate methane with graphitic carbon surfaces that allow for facile charge transfer. Dr. David Go, University of Notre Dame. Plasma Electrochemistry: A New Approach to Green Electrochemistry: to demonstrate the feasibility of using plasma electrochemistry to process carbon dioxide (CO ) for the production of alternative fuels, thereby ushering in a novel electrochemically-driven approach to both capture and reutilize CO , reducing the overall carbon footprint of automobiles.
News Article | February 4, 2016
Illinois mechanical science and engineering professor Kyle Smith and graduate student Rylan Dmello published their work in the Journal of the Electrochemical Society. "We are developing a device that will use the materials in batteries to take salt out of water with the smallest amount of energy that we can," Smith said. "One thing I'm excited about is that by publishing this paper, we're introducing a new type of device to the battery community and to the desalination community." Interest in water desalination technology has risen as water needs have grown, particularly in drought-stricken areas. However, technical hurdles and the enormous amounts of energy required have prevented wide-scale implementation. The most-used method, reverse osmosis, pushes water through a membrane that keeps out the salt, a costly and energy-intensive process. By contrast, the battery method uses electricity to draw charged salt ions out of the water. The researchers were inspired by sodium ion batteries, which contain salt water. Batteries have two chambers, a positive electrode and a negative electrode, with a separator in between that the ions can flow across. When the battery discharges, the sodium and chloride ions - the two elements of salt - are drawn to one chamber, leaving desalinated water in the other. In a normal battery, the ions diffuse back when the current flows the other direction. The Illinois researchers had to find a way to keep the salt out of the now-pure water. "In a conventional battery, the separator allows salt to diffuse from the positive electrode into the negative electrode," Smith said. "That limits how much salt depletion can occur. We put a membrane that blocks sodium between the two electrodes, so we could keep it out of the side that's desalinated." See a video of how it works on YouTube at https://www.youtube.com/watch?v=3QWoEOAlOzM&feature=youtu.be. The battery approach holds several advantages over reverse osmosis. The battery device can be small or large, adapting to different applications, while reverse osmosis plants must be very large to be efficient and cost effective, Smith said. The pressure required to pump the water through is much less, since it's simply flowing the water over the electrodes instead of forcing it through a membrane. This translates to much smaller energy needs, close to the very minimum required by nature, which in turn translates to lower costs. In addition, the rate of water flowing through it can be adjusted more easily than other types of desalination technologies that require more complex plumbing. Smith and Dmello conducted a modeling study to see how their device might perform with salt concentrations as high as seawater, and found that it could recover an estimated 80 percent of desalinated water. Their simulations don't account for other contaminants in the water, however, so they are working toward running experiments with real seawater. "We believe there's a lot of promise," Smith said. "There's a lot of work that's gone on in developing new materials for sodium ion batteries. We hope our work could spur researchers in that area to investigate new materials for desalination. We're excited to see what kind of doors this might open." Explore further: New entropy battery pulls energy from difference in salinity between fresh water and seawater More information: Kyle C. Smith et al. Na-Ion Desalination (NID) Enabled by Na-Blocking Membranes and Symmetric Na-Intercalation: Porous-Electrode Modeling, Journal of The Electrochemical Society (2016). DOI: 10.1149/2.0761603jes
News Article | January 13, 2016
The ability to store large amounts of electricity and deliver it later when it's needed will be critical if intermittent renewable energy sources such as solar and wind are to be deployed at scales that help curtail climate change in the coming decades. Such large-scale storage would also make today's power grid more resilient and efficient, allowing operators to deliver quick supplies during outages and to meet temporary demand peaks without maintaining extra generating capacity that's expensive and rarely used. A decade ago, the committee planning the new MIT Energy Initiative approached Donald Sadoway, MIT's John F. Elliott Professor of Materials Chemistry, to take on the challenge of grid-scale energy storage. At the time, MIT research focused on the lithium-ion battery—then a relatively new technology. The lithium-ion batteries being developed were small, lightweight, and short-lived—not a problem for mobile devices, which are typically upgraded every few years, but an issue for grid use. A battery for the power grid had to be able to operate reliably for years. It could be large and stationary, but—most important—it had to be inexpensive. "The classic academic approach of inventing the coolest chemistry and then trying to reduce costs in the manufacturing stage wouldn't work," says Sadoway. "In the energy sector, you're competing against hydrocarbons, and they're deeply entrenched and heavily subsidized and tenacious." Making a dramatic shift in power production would require a different way of thinking about storage. Sadoway therefore turned to a process he knew well: aluminum smelting. Aluminum smelting is a huge-scale, inexpensive process conducted inside electrochemical cells that operate reliably over long periods and produce metal at very low cost while consuming large amounts of electrical energy. Sadoway thought: "Could we run the smelter in reverse so it gives back its electricity?" Subsequent investigation led to the liquid metal battery. Like a conventional battery, this one has top and bottom electrodes with an electrolyte between them (see Figure 1 in the slideshow above). During discharging and recharging, positively charged metallic ions travel from one electrode to the other through the electrolyte, and electrons make the same trip through an external circuit. In most batteries, the electrodes—and sometimes the electrolyte—are solid. But in Sadoway's battery, all three are liquid. The negative electrode—the top layer in the battery—is a low-density liquid metal that readily donates electrons. The positive electrode—the bottom layer—is a high-density liquid metal that's happy to accept those electrons. And the electrolyte—the middle layer—is a molten salt that transfers charged particles but won't mix with the materials above or below. Because of the differences in density and the immiscibility of the three materials, they naturally settle into three distinct layers and remain separate as the battery operates. This novel approach provides a number of benefits. Because the components are liquid, the transfer of electrical charges and chemical constituents within each component and from one to another is ultrafast, permitting the rapid flow of large currents into and out of the battery. When the battery discharges, the top layer of molten metal gets thinner and the bottom one gets thicker. When it charges, the thicknesses reverse. There are no stresses involved, notes Sadoway. "The entire system is very pliable and just takes the shape of the container." While solid electrodes are prone to cracking and other forms of mechanical failure over time, liquid electrodes do not degrade with use. Indeed, every time the battery is charged, ions from the top metal that have been deposited into the bottom layer are returned to the top layer, purifying the electrolyte in the process. All three components are reconstituted. In addition, because the components naturally self-segregate, there's no need for membranes or separators, which are subject to wear. The liquid battery should perform many charges and discharges without losing capacity or requiring maintenance or service. And the self-segregating nature of the liquid components could facilitate simpler, less-expensive manufacturing compared to conventional batteries. For Sadoway and then-graduate student David Bradwell MEng '06, PhD '11, the challenge was to choose the best materials for the new battery, particularly for its electrodes. Methods exist for predicting how solid metals will behave under defined conditions. But those methods "were of no value to us because we wanted to model the liquid state," says Sadoway—and nobody else was working in this area. So he had to draw on what he calls "informed intuition," based on his experience working in electrometallurgy and teaching a large freshman chemistry class. To keep costs down, Sadoway and Bradwell needed to use electrode materials that were earth-abundant, inexpensive, and long-lived. To achieve high voltage, they had to pair a strong electron donor with a strong electron acceptor. The top electrode (the electron donor) had to be low density, and the bottom electrode (the electron acceptor) high density. "Mercifully," says Sadoway, "the way the periodic table is laid out, the strong electropositive [donor] metals are low density, and the strong electronegative [acceptor] metals are high density" (see Figure 2 in the slideshow above). And finally, all the materials had to be liquid at practical temperatures. As their first combination, Sadoway and Bradwell chose magnesium for the top electrode, antimony for the bottom electrode, and a salt mixture containing magnesium chloride for the electrolyte. They then built prototypes of their cell—and they worked. The three liquid components self-segregated, and the battery performed as they had predicted. Spurred by their success, in 2010 they, along with Luis Ortiz SB '96, PhD '00, also a former member of Sadoway's research group, founded a company—called initially the Liquid Metal Battery Corporation and later Ambri—to continue developing and scaling up the novel technology. Not there yet But there was a problem. To keep the components melted, the battery had to operate at 700 degrees Celsius (1,292 degrees Farenheit). Running that hot consumed some of the electrical output of the battery and increased the rate at which secondary components, such as the cell wall, would corrode and degrade. So Sadoway, Bradwell, and their colleagues at MIT continued the search for active materials. Early results from the magnesium and antimony cell chemistry had clearly demonstrated the viability of the liquid metal battery concept; as a result, the on-campus research effort received more than $11 million from funders including Total and the U.S. Department of Energy's ARPA–E program. The influx of research dollars enabled Sadoway to grow the research team at MIT to nearly 20 graduate and undergraduate students and postdocs who were ready to take on the challenge. Within months, the team began to churn out new chemistry options based on various materials with lower melting points. For example, in place of the antimony, they used lead, tin, bismuth, and alloys of similar metals; and in place of the magnesium, they used sodium, lithium, and alloys of magnesium with such metals as calcium. The researchers soon realized that they were not just searching for a new battery chemistry. Instead, they had discovered a new battery "platform" from which a multitude of potentially commercially viable cell technologies with a range of attributes could spawn. New cell chemistries began to show significant reductions in operating temperature. Cells of sodium and bismuth operated at 560 degrees Celsius. Lithium and bismuth cells operated at 550 C. And a battery with a negative electrode of lithium and a positive electrode of an antimony-lead alloy operated at 450 C. While working with the last combination, the researchers stumbled on an unexpected electrochemical phenomenon: They found that they could maintain the high cell voltage of their original pure antimony electrode with the new antimony-lead version—even when they made the composition as much as 80 percent lead in order to lower the melting temperature by hundreds of degrees. "To our pleasant surprise, adding more lead to the antimony didn't decrease the voltage, and now we understand why," Sadoway says. "When lithium enters into an alloy of antimony and lead, the lithium preferentially reacts with the antimony because it's a tighter bond. So when the lithium [from the top electrode] enters the bottom electrode, it ignores the lead and bonds with the antimony." That unexpected finding reminded them how little was known in this new field of research—and also suggested new cell chemistries to explore. For example, they recently assembled a proof-of-concept cell using a positive electrode of a lead-bismuth alloy, a negative electrode of sodium metal, and a novel electrolyte of a mixed hydroxide-halide. The cell operated at just 270 C—more than 400 C lower than the initial magnesium-antimony battery while maintaining the same novel cell design of three naturally separating liquid layers. The role of the new technology The liquid metal battery platform offers an unusual combination of features. In general, batteries are characterized by how much energy and how much power they can provide. (Energy is the total amount of work that can be done; power is how quickly work gets done.) In general, technologies do better on one measure than the other. For example, with capacitors, fast delivery is cheap, but abundant storage is expensive. With pumped hydropower, the opposite is true. But for grid-scale storage, both capabilities are important—and the liquid metal battery can potentially do both. It can store a lot of energy (say, enough to last through a blackout) and deliver that energy quickly (for example, to meet demand instantly when a cloud passes in front of the sun). Unlike the lithium-ion battery, it should have a long lifetime; and unlike the lead-acid battery, it will not be degraded when being completely discharged. And while it now appears more expensive than pumped hydropower, the battery has no limitation on where it can be used. With pumped hydro, water is pumped uphill to a reservoir and then released through a turbine to generate power when it's needed. Installations therefore require both a hillside and a source of water. The liquid metal battery can be installed essentially anywhere. No need for a hill or water. Ambri has now designed and built a manufacturing plant for the liquid metal battery in Marlborough, Massachusetts. As expected, manufacturing is straightforward: Just add the electrode metals plus the electrolyte salt to a steel container and heat the can to the specified operating temperature. The materials melt into neat liquid layers to form the electrodes and electrolyte. The cell manufacturing process has been developed and implemented and will undergo continuous improvement. The next step will involve automating the processes to aggregate many cells into a large-format battery including the power electronics. Ambri has not been public about which liquid metal battery chemistry it is commercializing, but it does say that it has been working on the same chemistry for the past four years. According to Bradwell, Ambri scientists and engineers have built more than 2,500 liquid metal battery cells and have achieved thousands of charge-discharge cycles with negligible reduction in the amount of energy stored. Those demonstrations confirm Sadoway and Bradwell's initial thesis that an all-liquid battery would be poised to achieve better performance than solid-state alternatives and would be able to operate for decades. Ambri researchers are now tackling one final engineering challenge: developing a low-cost, practical seal that will stop air from leaking into each individual cell, thus enabling years of high-temperature operation. Once the needed seals are developed and tested, battery production will begin. The researchers plan to deliver prototypes for field testing in several locations, including Hawaii, where sunshine is abundant but power generation still relies on burning expensive diesel fuel. One site is the Pearl Harbor naval base on Oahu. "It's unsettling that our military bases rely on the civilian power grid," says Sadoway. "If that grid goes down, the base must power up diesel generators to fill the gap. So the base can be without power for about 15 minutes, which is probably enough time for some major damage to be done." The new battery could play a key role in preventing such an outcome. Meanwhile, back at the lab, the MIT researchers are continuing to explore other chemistries for the core of the liquid battery. Indeed, Sadoway says that his team has already developed an alternative design that offers even lower operating temperatures, more stored energy, lower cost, and a longer lifetime. Given the general lack of knowledge about the properties and potential uses of liquid metals, Sadoway believes there could still be major discoveries in the field. The results of their experiments "kicked open the doors to a whole bunch of other choices that we've made," says Sadoway. "It was really cool." More information: David J. Bradwell et al. Magnesium–Antimony Liquid Metal Battery for Stationary Energy Storage, Journal of the American Chemical Society (2012). DOI: 10.1021/ja209759s Xiaohui Ning et al. Self-healing Li–Bi liquid metal battery for grid-scale energy storage, Journal of Power Sources (2015). DOI: 10.1016/j.jpowsour.2014.10.173 Brian L. Spatocco et al. Low-Temperature Molten Salt Electrolytes for Membrane-Free Sodium Metal Batteries, Journal of The Electrochemical Society (2015). DOI: 10.1149/2.0441514jes
News Article | August 25, 2016
« Technip signs agreement with BTG Bioliquids to design and build pyrolysis plants for biomass-to-oil production | Main | U-M study finds crop-based biofuels associated with net increase in GHGs; falsifying the assumption of inherent carbon neutrality » Using commercially available solar cells and none of the usual rare metals, researchers at the Swiss Center for Electronics and Microtechnology (CSEM) and École Polytechnique Fédérale de Lausanne (EPFL) have designed an intrinsically stable and scalable solar water splitting device that is fully based on earth-abundant materials, with a solar-to-hydrogen conversion efficiency of 14.2%. The prototype system is made up of three interconnected, new-generation, crystalline silicon solar cells attached to an electrolysis system that does not rely on rare metals. The device has already been run for more than 100 hours straight under test conditions. The method, which surpasses previous efforts in terms of stability, performance, lifespan and cost efficiency, is published in the Journal of The Electrochemical Society. crystalline Silicon (c-Si) solar cells show high solar-to-electricity efficiencies, and have demonstrated stabilities in excess of 25 years. Propelled by their attractive performance, they have continuously dominated the market since their inception, with a current worldwide market share greater than 85%. Their high production volumes have largely contributed to a price drop of 80% since 2008, currently reaching levels below $1 per watt peak. … Recently, c-Si modules have been implemented in solar-hydrogen devices, demonstrating SHE [solar-to-hydrogen efficiency] of 9.7%. As the V of the presented c-Si cells is only ∼600 mV, four cells need to be connected in series to achieve stable water splitting performance. This results in lower operating currents and limited SHE efficiencies. Alternatively, c-Si-based heterojunction (SHJ) cells can reach V values in excess of 700 mV. These VOC values are the highest ones reported for silicon wafer-based technologies, and are predominantly obtained by an excellent interface passivation with a thin (∼5 nm) film of hydrogenated intrinsic amorphous silicon (a-Si:H) between the c-Si wafer and the oppositely doped emitter, forming the p-n junction. We demonstrate in this study that, thanks to their high V , three series-connected SHJ cells can already stably drive the water splitting reaction at unprecedented SHE. In terms of performance, this is a world record for silicon solar cells and for hydrogen production without using rare metals. The key here is making the most of existing components, and using a hybrid-type of crystalline-silicon solar cell based on heterojunction technology. The researchers’ sandwich structure—using layers of crystalline silicon and amorphous silicon—allows for higher voltages needed to power directly the microstructured Ni electrocatalysts. Nearly identical performance levels were also achieved using a customized state-of-the-art proton exchange membrane (PEM) electrolyzer. The researchers used standard heterojunction cells to prove the concept; by using the best cells of that type, they would expect to achieve a performance above 16%. The research is part of the nano-tera SHINE— project to develop an efficient and cost-effective hydrogen production system using sunlight and water.
News Article | March 31, 2016
Reference electrodes (REs) are used to measure the voltages of individual electrodes that make up the battery cell. "Such information is critical, especially when developing batteries for larger-scale applications, such as electric vehicles, that have far greater energy density and longevity requirements than typical batteries in cell phones and laptop computers," said Argonne battery researcher Daniel Abraham, co-author of a newly published study in the Journal of The Electrochemical Society. "This kind of detailed information provides insight into a battery cell's health; it's the type of information that researchers need to evaluate battery materials at all stages of their development." Argonne battery researchers have been at the forefront of using REs to evaluate the performance of lithium-ion cells, Abraham said. Their studies have provided crucial insights into cell aging phenomena, including the effects of test temperatures and cycling voltages. Mitigating the root causes of aging can increase cell longevity and improve the commercial viability for applications that require long-term battery durability. Until recently, Argonne battery researchers would use only one RE, based on a lithium-tin (Li-Sn) alloy, to collect information. However, Abraham's team found that by sandwiching a Li-Sn RE between the positive and negative electrodes, while simultaneously positioning a pure Li metal RE next to the stack, they could obtain insights into electrode state-of-charge shifts, active material use, active material loss and impedance changes. In testing the new RE configuration, researchers used a cell containing a lithiated oxide cathode (NCM-523), an Argonne-developed silicon-graphite anode (Si-Gr) and various electrolytes, including ones with fluoroethylene carbonate (FEC) or vinylene carbonate (VC) additives. Both NCM-523 and Si-Gr are materials of interest for high-energy-density lithium-ion batteries being developed to extend the driving range of vehicles. "Silicon-containing electrodes could double the energy stored in lithium-ion cells," said Abraham. But because Si-containing cells degrade more quickly, the Argonne team wanted to know the impact of the FEC and VC addition to the cell electrolyte. "Our new RE configuration confirms the beneficial impact of these additives, not only in reducing capacity loss but also in mitigating the impedance rise displayed by cells without these additives," he added. More information: Matilda Klett et al. Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li (Ni Co Mn ) O /Silicon-Graphite Full Cells , Journal of The Electrochemical Society (2016). DOI: 10.1149/2.0271606jes