Georgia Institute of Technology researchers have developed a promising new cathode and electrolyte system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte.

The growing popularity of lithium-ion batteries in recent years has put a strain on the world’s supply of cobalt and nickel, two metals integral to current battery designs, and sent prices surging.

A lithium-ion battery is shown using a promising new cathode and electrolyte system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte. Image Credit: Allison Carter, Georgia Institute of Technology. Click image for the largest view.

In an effort to develop alternative designs for lithium-based batteries with less reliance on those scarce metals, researchers at the Georgia Institute of Technology have developed a promising new cathode and electrolyte system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte.

Gleb Yushin, a professor in Georgia Tech’s School of Materials Science and Engineering explained, “Electrodes made from transition metal fluorides have long shown stability problems and rapid failure, leading to significant skepticism about their ability to be used in next generation batteries. But we’ve shown that when used with a solid polymer electrolyte, the metal fluorides show remarkable stability – even at higher temperatures – which could eventually lead to safer, lighter and cheaper lithium-ion batteries.”

In a typical lithium-ion battery, energy is released during the transfer of lithium ions between two electrodes, an anode and a cathode, with a cathode typically comprising lithium and transition metals such as cobalt, nickel and manganese. The ions flow between the electrodes through a liquid electrolyte.

For the study, published in the journal Nature Materials and sponsored by the Army Research Office, the research team fabricated a new type of cathode from iron fluoride active material and a solid polymer electrolyte nanocomposite. Iron fluorides have more than double the lithium capacity of traditional cobalt- or nickel-based cathodes. In addition, iron is 300 times cheaper than cobalt and 150 times cheaper than nickel.

To produce such a cathode, the researchers developed a process to infiltrate a solid polymer electrolyte into the prefabricated iron fluoride electrode. They then hot pressed the entire structure to increase density and reduce any voids.

Two central features of the polymer-based electrolyte are its ability to flex and accommodate the swelling of the iron fluoride while cycling and its ability to form a very stable and flexible interphase with iron fluoride. Traditionally, that swelling and massive side reactions have been key problems with using iron fluoride in previous battery designs.

Yushin said, “Cathodes made from iron fluoride have enormous potential because of their high capacity, low material costs and very broad availability of iron. But the volume changes during cycling as well as parasitic side reactions with liquid electrolytes and other degradation issues have limited their use previously. Using a solid electrolyte with elastic properties solves many of these problems.”

The researchers then tested several variations of the new solid-state batteries to analyze their performance over more than 300 cycles of charging and discharging at elevated temperature of 122° Fahrenheit, noting that they outperformed previous designs using metal fluoride even when these were kept cool at room temperatures.

The researchers found that the key to the enhanced battery performance was the solid polymer electrolyte. In previous attempts to use metal fluorides, it was believed that metallic ions migrated to the surface of the cathode and eventually dissolved into the liquid electrolyte, causing a capacity loss, particularly at elevated temperatures. In addition, metal fluorides catalyzed massive decomposition of liquid electrolytes when cells were operating above 100° Fahrenheit. However, at the connection between the solid electrolyte and the cathode, such dissolving doesn’t take place and the solid electrolyte remains remarkably stable, preventing such degradations, the researchers wrote.

Kostiantyn Turcheniuk, research scientist in Yushin’s lab and a co-author of the manuscript said, “The polymer electrolyte we used was very common, but many other solid electrolytes and other battery or electrode architectures – such as core-shell particle morphologies – should be able to similarly dramatically mitigate or even fully prevent parasitic side reactions and attain stable performance characteristics.”

In the future, the researchers aim to develop new and improved solid electrolytes to enable fast charging and also to combine solid and liquid electrolytes in new designs that are fully compatible with conventional cell manufacturing technologies employed in large battery factories.

This seems to be a major improvement to an expensive and battery life limiting situation. As the previous paragraph notes, the manufacturing base is invested in existing technology that needs worked through to get this kind of improvement to marketed products.

The press release suggests the Georgia folks have a firm grip on the handle of what needs done. The progress reported so far implies that they are going to offer manufacturers a much lower cost and better battery design for sale to consumers.

Georgia Institute of Technology researchers have developed a new platinum-based catalytic system that is far more durable than traditional commercial systems and has a potentially longer lifespan. The new system could, over the long term, reduce the cost of producing fuel cells.

Platinum has long been used as a catalyst to enable the oxidation reduction reaction at the center of fuel cell technology. But the metal’s high cost is one factor that has hindered fuel cells from competing with cheaper ways of powering automobiles and homes.

Now researchers at the Georgia Institute of Technology have developed a new platinum-based catalytic system that is far more durable than traditional commercial systems and has a potentially longer lifespan. The new system could, over the long term, reduce the cost of producing fuel cells.

In the study, which was published in the ACS journal Nano Letters, the researchers described a possible new way to solve one of the key causes of degradation of platinum catalysts, sintering, a process in which particles of platinum migrate and clump together, reducing the specific surface area of the platinum and causing the catalytic activity to drop.

To reduce such sintering, the researchers devised a method to anchor the platinum particles to their carbon support material using bits of the element selenium.

Zhengming Cao, a visiting graduate student at Georgia Tech said, “There are strategies out there to mitigate sintering, such as using platinum particles that are uniform in size to reduce chemical instability among them. This new method using selenium results in a strong metal-support interaction between platinum and the carbon support material and thus remarkably enhanced durability. At the same time, the platinum particles can be used and kept at a small to attain high catalytic activity from the increased specific surface area.”

The process starts by loading nanoscale spheres of selenium onto the surface of a commercial carbon support. The selenium is then melted under high temperatures so that it spreads and uniformly covers the surface of the carbon. Then, the selenium is reacted with a salt precursor to platinum to generate particles of platinum smaller than two nanometers in diameter and evenly distributed across the carbon surface.

The covalent interaction between the selenium and platinum provides a strong link to stably anchor the platinum particles to the carbon.

Younan Xia, professor and Brock Family Chair in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University added, “The resulting catalyst system was remarkable both for its high activity as a catalyst as well as its durability.”

Because of the increased specific surface area of the nanoscale platinum, the new catalytic system initially showed catalytic activity three and a half times higher than the pristine value of a state-of-the-art commercial platinum-carbon catalyst. Then, the research team tested the catalytic system using an accelerated durability test. Even after 20,000 cycles of electropotential sweeping, the new system still provided a catalytic activity more than three times that of the commercial system.

The researchers used transmission electron microscopy at different stages of the durability test to examine why catalytic activity remained so high. They found that the selenium anchors were effective in keeping most of the platinum particles in place.

“After 20,000 cycles, most of the particles remained on the carbon support without detachment or aggregation,” Cao said. “We believe this type of catalytic system holds great potential as a scalable way to increase the durability and activity of platinum catalysts and eventually improve the feasibility of using fuel cells for a wider range of applications.”

Without doubt the cost of platinum is a large and deep set anchor on fuel cell adoption. Most alternatives while cheaper are not commercial for a variety of reasons, some of which may make it to market someday.

But 20,000 cycles is a new and amazing change in perspective. 20,000 cycles over / 365 days = 54.8 years. That offers a very different amortization result. Still the initial capital investment is a major hurdle. Not something a family or small business is likely to entertain.

Rice University researchers have built a electrocatalysis reactor that recycles carbon dioxide to produce pure liquid fuel solutions using electricity. The scientists behind the invention hope it will become an efficient and profitable way to recycle and reuse CO2.

The CO2 could be repurposed in an efficient and environmentally friendly way with the new electrolyzer that uses renewable electricity to produce pure liquid fuels.

Schematic illustration of the CO2 reduction cell with solid electrolyte. Image Credit: Rice University. Click image for a larger view.

The catalytic reactor developed by the Rice University lab of chemical and biomolecular engineer Haotian Wang uses carbon dioxide as its feedstock and, in its latest prototype, produces highly purified and high concentrations of formic acid.

Formic acid produced by traditional carbon dioxide devices needs costly and energy-intensive purification steps Wang explained. The direct production of pure formic acid solutions will help to promote commercial carbon dioxide conversion technologies.

The Wang group’s study paper has been published in Nature Energy.

Wang, who joined Rice’s Brown School of Engineering in January, and his group pursue technologies that turn greenhouse gases into useful products. In tests, the new electrocatalyst reached an energy conversion efficiency of about 42%. That means nearly half of the electrical energy can be stored in formic acid as liquid fuel.

“Formic acid is an energy carrier,” Wang said. “It’s a fuel-cell fuel that can generate electricity and emit carbon dioxide – which you can grab and recycle again.”

“It’s also fundamental in the chemical engineering industry as a feedstock for other chemicals, and a storage material for hydrogen that can hold nearly 1,000 times the energy of the same volume of hydrogen gas, which is difficult to compress,” he said. “That’s currently a big challenge for hydrogen fuel-cell cars.”

Two advances made the new device possible, said lead author and Rice postdoctoral researcher Chuan Xia. The first was his development of a robust, two-dimensional bismuth catalyst and the second a solid-state electrolyte that eliminates the need for salt as part of the reaction.

“Bismuth is a very heavy atom, compared to transition metals like copper, iron or cobalt,” Wang said. “Its mobility is much lower, particularly under reaction conditions. So that stabilizes the catalyst.” He noted the reactor is structured to keep water from contacting the catalyst, which also helps preserve it.

Xia can make the nanomaterials in bulk. “Currently, people produce catalysts on the milligram or gram scales,” he said. “We developed a way to produce them at the kilogram scale. That will make our process easier to scale up for industry.”

The polymer-based solid electrolyte is coated with sulfonic acid ligands to conduct positive charge or amino functional groups to conduct negative ions.

“Usually people reduce carbon dioxide in a traditional liquid electrolyte like salty water,” Wang said. “You want the electricity to be conducted, but pure water electrolyte is too resistant. You need to add salts like sodium chloride or potassium bicarbonate so that ions can move freely in water.”

“But when you generate formic acid that way, it mixes with the salts,” he said. “For a majority of applications you have to remove the salts from the end product, which takes a lot of energy and cost. So we employed solid electrolytes that conduct protons and can be made of insoluble polymers or inorganic compounds, eliminating the need for salts.”

The rate at which water flows through the product chamber determines the concentration of the solution. Slow throughput with the current setup produces a solution that is nearly 30% formic acid by weight, while faster flows allow the concentration to be customized. The researchers expect to achieve higher concentrations from next-generation reactors that accept gas flow to bring out pure formic acid vapors.

The Rice lab worked with Brookhaven National Laboratory to view the process in progress. “X-ray absorption spectroscopy, a powerful technique available at the Inner Shell Spectroscopy (ISS) beamline at Brookhaven Lab’s National Synchrotron Light Source II, enables us to probe the electronic structure of electrocatalysts in operando – that is, during the actual chemical process,” said co-author Eli Stavitski, lead beamline scientist at ISS. “In this work, we followed bismuth’s oxidation states at different potentials and were able to identify the catalyst’s active state during carbon dioxide reduction.”

With its current reactor, the lab generated formic acid continuously for 100 hours with negligible degradation of the reactor’s components, including the nanoscale catalysts. Wang suggested the reactor could be easily retooled to produce such higher-value products as acetic acid, ethanol or propanol fuels.

“The big picture is that carbon dioxide reduction is very important for its effect on global warming as well as for green chemical synthesis,” Wang said. “If the electricity comes from renewable sources like the sun or wind, we can create a loop that turns carbon dioxide into something important without emitting more of it.”

Co-authors are Rice graduate student Peng Zhu; graduate student Qiu Jiang and Husam Alshareef, a professor of material science and engineering, at King Abdullah University of Science and Technology, Saudi Arabia (KAUST); postdoctoral researcher Ying Pan of Harvard University; and staff scientist Wentao Liang of Northeastern University. Wang is the William Marsh Rice Trustee Assistant Professor of Chemical and Biomolecular Engineering. Xia is a J. Evans Attwell-Welch Postdoctoral Fellow at Rice.

Rice and the U.S. Department of Energy Office of Science User Facilities supported the research.

This work is likely to have a major impact over time. Recycling CO2 back into a fuel source has immense potential and helps moderate the expectation of higher fuel prices out into the future. Like all possible disruptive technologies, the cost of the product is paramount, so driving to low cost efficiency is key.

The other takeaway is the potential to store hydrogen. The smallest atom as a fuel market has yet to find a practical and economical means of storage, This tech might well find its path into the market in this field instead.

Lets hope there is much more to come from this group. They’re bumped into two future fuel markets in need of their technology’s success.

Stanford researchers have made a significant advance in the development of artificial catalysts.  The progress offers ways to make cleaner chemicals and fuels at an industrial scale.

All living organisms depend on enzymes, molecules that speed up biochemical reactions that are essential for life and scientists have spent decades trying to create artificial enzymes capable of cranking out important chemicals and fuels at an industrial scale with performance rivaling their natural counterparts.

Scientists have invented an enzyme-like catalyst made of soft polymers (purple) and a hard palladium core (pink). When heated, the palladium chemically converts molecules of oxygen and carbon monoxide (yellow and orange) into carbon dioxide. The reaction stops when the polymers are saturated with carbon dioxide, a strategy used by living enzymes. Research is underway to develop catalysts that convert natural gas to methanol at low temperatures. Image Credit: Gregory Stewart/SLAC National Accelerator Laboratory.

Researchers from Stanford University and SLAC National Accelerator Laboratory have developed a synthetic catalyst that produces chemicals much the way enzymes do in living organisms.

In a study published in the Aug. 5 issue of Nature Catalysis, the researchers say their discovery could lead to industrial catalysts capable of producing methanol using less energy and at a lower cost. Methanol has a variety of applications, and there is a growing demand for its use as a fuel with lower emissions than conventional gasoline.

Senior author Matteo Cargnello, an assistant professor of chemical engineering at Stanford said, “We took our inspiration from nature. We wanted to mimic the function of natural enzymes in the laboratory using artificial catalysts to make useful compounds.”

For the experiment, the researchers designed a catalyst made of nanocrystals of palladium, a precious metal, embedded in layers of porous polymers tailored with special catalytic properties. Most protein enzymes found in nature also have trace metals, like zinc and iron, embedded in their core.

The researchers were able to observe trace palladium in their catalysts with electron microscopic imagery by co-author Andrew Herzing of the National Institute of Standards and Technology.

Lead author of the study PhD student Andrew Riscoe said, “We focused on a model chemical reaction: converting toxic carbon monoxide and oxygen into carbon dioxide (CO2). Our goal was to see if the artificial catalyst would function like an enzyme by speeding up the reaction and controlling the way CO2 is produced.”

To find out, Riscoe placed the catalyst in a reactor tube with a continuous flow of carbon monoxide and oxygen gas. When the tube was heated to about 150° Celsius (302° Fahrenheit), the catalyst began generating the desired product, carbon dioxide.

High-energy X-rays from the Stanford Synchrotron Radiation Lightsource (SSRL) at SLAC revealed that the catalyst had traits similar to those seen in enzymes: The palladium nanocrystals inside the catalyst were continuously reacting with oxygen and carbon monoxide to produce carbon dioxide. And some of the newly formed carbon dioxide molecules were getting trapped in the outer polymer layers as they escaped from the nanocrystals.

“The X-rays showed that once the polymer layers were filled with CO2, the reaction stopped,” said Cargnello, who is also an affiliate with the Stanford Natural Gas Initiative (NGI). “This is important, because it’s the same strategy used by enzymes. When an enzyme produces too much of a product, it stops working, because the product is no longer needed. We showed that we can also regulate the production of CO2 by controlling the chemical composition of the polymer layers. This approach could impact many areas of catalysis.”

The X-ray imaging was conducted by study co-authors Alexey Boubnov, a Stanford postdoctoral scholar, and SLAC scientists Simon Bare and Adam Hoffman.

With the success of the carbon dioxide experiment, Cargnello and his colleagues have turned their attention to converting methane, the main ingredient in natural gas, into methanol, a chemical widely used in textiles, plastics and paints. Methanol has also been touted as a cheaper, cleaner alternative to gasoline fuel.

“The ability to convert methane to methanol at low temperatures is considered a holy grail of catalysis,” Cargnello said. “Our long-term goal is to build a catalyst that behaves like methane monooxoygenase, a natural enzyme that certain microbes use to metabolize methane.”

Most methanol today is produced in a two-step process that involves heating natural gas to temperatures of about 1,000° C (1,800° F). But this energy-intensive process emits a large amount of carbon dioxide, though by some to be a potent greenhouse gas that contributes to global climate change.

“An artificial catalyst that directly converts methane to methanol would require much lower temperatures and emit far less CO2,” Riscoe explained. “Ideally, we could also control the products of the reaction by designing polymer layers that trap the methanol before it burns.”

Cargnello who is also affiliated with Stanford’s SUNCAT Center for Interface Science and Catalysis said in summary, “In this work, we demonstrated that we can prepare hybrid materials made of polymers and metallic nanocrystals that have certain traits typical of enzymatic activity. The exciting part is that we can apply these materials to lots of systems, helping us better understand the details of the catalytic process and taking us one step closer to artificial enzymes.”

Additional co-authors include Stanford PhD student Cody Wrasman, and high school interns Aditya Menon and Maria Vargas with support from Stanford’s Raising Interest in Science and Engineering (RISE) program.

The past decade has seen an immense rush of progress in the materials field. As this news points out, the progress can reasonably be expected to come even faster and more productively in the coming years. While there isn’t an expectation this team will back in glory, if fair to say this is breakthough work that very well make major changes to chemical production across a wide range of products.

Texas A&M University researchers have synthesized several polymers that adopt different conformations, such as a random coil, an alpha helix and a beta sheet, to investigate their electrochemical characteristics. The Texas A&M researchers presented their results at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition early last week.

Proteins are good for building muscle, but their building blocks also might be helpful for building sustainable organic batteries that could someday be a viable substitute for conventional lithium-ion batteries, without their safety and environmental concerns. By using synthetic polypeptides – which make up proteins – and other polymers, researchers have taken the first steps toward constructing electrodes for such power sources. The work could also provide a new understanding of electron-transfer mechanisms.

Tan Nguyen, a Ph.D. student who helped develop the project said, “The trend in the battery field right now is to look at how the electrons are transported within a polymer network. The beauty of polypeptides is that we can control the chemistry on their side chains in 3D without changing the geometry of the backbone, or the main part of the structure. Then we can systematically examine the effect of changing different aspects of the side chains.”

Current lithium-ion batteries can harm the environment, and because the cost of recycling them is higher than manufacturing them from scratch, they often accumulate in landfills. At the moment, there is no safe way of disposing of them. Developing a protein-based, or organic, battery would change this situation.

Karen Wooley, Ph.D., who leads the team at Texas A&M University explains the work in more depth, “The amide bonds along the peptide backbone are pretty stable – so the durability is there, and we can then trigger when they break down for recycling.” She envisions that polypeptides could eventually be used in applications such as flow batteries for storing electrical energy.

Wooley added, “The other advantage is that by using this protein-like architecture, we’re building in the kinds of conformations that are found in proteins in nature that already transport electrons efficiently. We can also optimize this to control battery performance.”

The researchers built the system using electrodes made of composites of carbon black, constructing polypeptides that contain either viologen or 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). They attached viologens to the matrix used for the anode, which is the negative electrode, and used a TEMPO-containing polypeptide for the cathode, which is the positive electrode. The viologens and TEMPO are redox-active molecules.

Nguyen noted, “What we’ve measured so far for the range, the potential window between the two materials, is about 1.5 volts, suitable for low-energy requirement applications, such as biosensors.”

For potential use in an organic battery, Nguyen has synthesized several polymers that adopt different conformations, such as a random coil, an alpha helix and a beta sheet, to investigate their electrochemical characteristics. With these peptides in hand, Nguyen is now collaborating with Alexandra Danielle Easley, a Ph.D. student in the laboratory of Jodie Lutkenhaus, Ph.D., also at Texas A&M University, to build the battery prototypes. Part of that work will include testing to better understand how the polymers function when they’re organized on a substrate.

While this early stage research has far to go before organic-based batteries are commercially available, the flexibility and variety of structures that proteins can provide promise wide potential for sustainable energy storage that is safer for the environment.

Over time this kind of research is going to become much more important. Most folks aren’t aware just how nasty a disintegrating lithium ion battery is. We really don’t want them in our homes at all and certainly throwing them away conventionally sends them to a landfill which is asking for large concentrated contamination over time. They really are not your typical alkaline battery. Please recycle them.


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