A Rice University study suggests that lithium batteries would benefit from more porous electrodes with better-aligned particles that don’t limit lithium distribution. At the micro and nano scale resolution looking at a lithium battery electrode, you’d see the level of charge at every scale is highly uneven.

Rice University materials scientists suggests that lithium batteries would benefit from more porous secondary (agglomerated) particles with better-aligned crystallites that don’t limit lithium distribution. The scientists studied 3D transmission X-ray images of cycled battery electrodes to analyze the phase change between lithium iron phosphate (blue) and iron phosphate (red) on the surface of particle agglomerates that make up the electrodes. Image Credit: Mesoscale Materials Science Group via Rice University. Click image for the largest view.

This is not good for the battery’s health. Rice University researchers who recognize the problem worked with the Department of Energy to view in great detail how the various particles in an electrode interact with lithium during use.

Specifically, the Rice lab of materials scientist Ming Tang analyzed nano- and micro-scale interactions within lithium iron phosphate cathodes through modeling and imaging offered by the transmission X-ray microscopy capabilities at Brookhaven National Laboratory and Argonne National Laboratory.

Their paper in the American Chemical Society journal ACS Energy Letters supports theories Tang and his colleagues formed several years ago that foresaw how lithium travels in the dynamic environment inside a typical commercial cathode.

Being able to watch sealed cathodes charge and discharge at Brookhaven offered absolute proof.

Tang, an associate professor of materials science and nano engineering said, “Batteries have a lot of particle aggregates that soak up and give up lithium, and we wanted to know what happens on their surfaces, how uniform the reaction is. In general, we always want a more uniform reaction so we can charge the battery faster.”

In images taken at Brookhaven’s powerful X-ray synchrotron, the researchers saw some regions inside the cathode were better at absorption than others. The ability to look at single or aggregated particles in 3D showed that rather than reacting over their entire surfaces, lithium favored particular regions over others.

“This is very different from conventional wisdom,” Tang said. “The most interesting observation is that these reaction regions are shaped like one-dimensional filaments lying across the surface of these aggregated particles. It was kind of weird, but it matched what we saw in our models.”

Tang said the lithium filaments looked something like thick nanotubes and were several hundred nanometers wide and several microns long.

He said stress between misaligned crystallites in the particle agglomerates prevents lithium from being uniformly inserted into or extracted from the aggregate surface because that will generate too large an energy penalty. Instead, lithium is forced to flow into or out of the aggregates at “hot spots” that develop the filament shape.

What does this mean for battery performance?

“This is a bad thing,” Tang explained. “Because the lithium can’t go into the cathode uniformly, it slows down the intercalation mechanics.

“What our study offers is some potential ways to help make lithium insertion or extraction more uniform on these aggregates or individual particles,” he said. “Introducing some porosity in the particle agglomerates might sacrifice some energy density, but at the same time would allow lithium to go in more uniformly. That could allow you to get more energy at a given charge/discharge rate.

Additionally Tang offered, “Another thought is if we can somehow align the orientation of these small particles so their maximum expansion is perpendicular to each other, they’ll better accommodate lithium intercalation.”

That would be a challenge for battery manufacturers, he admitted. “We don’t have enough experience in synthesis to know how to make that happen,” Tang said. “What we’re providing is bait. Let’s see if somebody bites.”

Rice graduate alumni Fan Wang and Kaiqi Yang are co-lead authors of the paper. Co-authors are Mingyuan Ge, Jiajun Wang, Jun Wang, Xianghi Xiao and Wah-Keat Lee, all of Brookhaven National Laboratory, Upton, New York; and Linsen Li of Shanghai Jiao Tong University.

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This is another innovative deep look into battery chemistry. It also reveals that manufacturing processes have a way to go to optimize battery production and that its going to be a challenge. One is also noting that this level of refinement could very well have a positive effect on the development of other battery chemistries. Batteries on the whole might really still be in the early stages of development.

University of Delaware researchers have found a way to improve the ability of catalysts made from metal-metal oxides to convert non-edible plants, such as wood, grass and corn stover into renewable fuels, chemicals and plastics. Metal oxide catalysts are central to reactions for upgrading petrochemicals, fine chemicals, pharmaceuticals and biomass.

Catalysts are workhorses that help reactions occur. Put to work, they transform starting materials, such as fossil fuels, biomass or even waste, into products and fuels with minimal energy.

Pulsed hydrogen’s effect on catalyst reactivity. Image Credit University of Delaware. Click image for the largest view.

Researchers in the Catalysis Center for Energy Innovation (CCEI) at the University of Delaware have found a way to improve the ability of catalysts made from metal-metal oxides to convert non-edible plants, such as wood, grass and corn stover – the leaves, stalks and cobs leftover in the fields after harvest – into renewable fuels, chemicals and plastics.

The CCEI researchers reported their findings in Nature Catalysis.

The research team’s strategy capitalized on the dynamic nature of platinum-tungsten oxide catalysts to convert these starting materials into products up to 10 times faster than traditional methods. It’s the type of innovative catalytic technology that could help usher in a more sustainable and greener future, where processes require less catalyst to operate, leading to less waste and less overall energy use.

The surface of a catalyst contains multiple active sites at which chemical reactions occur. These active sites are sensitive and dynamic, changing in response to their environment in highly complex and often difficult-to-predict ways. As a result, little is known about how processes on these active sites operate or how the sites interact with their surroundings. Traditional approaches for increasing understanding, such as studying catalysts under static conditions in a chemical reactor, don’t work.

So the CCEI researchers combined modeling, advanced synthetic techniques, in-situ spectroscopies and probe reactions to get a better look at how platinum and tri-tungsten oxide catalyst materials come together, what structure they take and what happens on the catalyst’s surface. In particular, the research team was interested in how the active sites on a catalyst (where the chemical reactions occur) evolve over time and when exposed to specific changes.

Jiayi Fu, the paper’s lead author, who recently earned his UD doctoral degree in chemical engineering and now works at Bristol Myers Squibb said, “By identifying the telltale signs of their dynamics, we were able to establish, for the first time, a robust model to predict their behavior in various working environments.”

Fu explained that catalyst surfaces – like plants – flourish when given the proper balance of sunshine and sustenance. The research team successfully demonstrated a novel “irrigation” strategy which uses hydrogen pulsing to significantly increase the population of active sites on these catalysts, allowing reactions to occur 10 times faster.

Dion Vlachos, the Unidel Dan Rich Chair in Energy, professor of chemical and biomolecular engineering and director of CCEI explained, “We’re not actually watering the catalysts, that’s just a metaphor. But, by pulsing hydrogen gas on and off, we create these active sites that mimic water, through a process known as hydroxylation. These active sites then do the chemistry. So, like light and water feeds the plants, here we feed hydrogen to ‘water’ the catalyst and make it produce – or grow – new chemicals.”

The work illustrates a successful example of how simulations can predict catalytic behavior and enable the rational design of more efficient catalytic processes, said Vlachos, who also directs the Delaware Energy Institute. The findings also provide a viable way to study, understand and control this important class of catalysts.

“Catalysts are known to evolve and respond to their environment, but they do this quickly, in ways that have been hard to observe in real time,” he said. “This work sets a platform for how to dissect their working behavior and, importantly, how to engineer them for unprecedented performance enhancement.”

The UD-led project team at CCEI included researchers from the University of Delaware, the University of Pennsylvania, the University of Massachusetts Amherst, Brookhaven National Laboratory, Stony Brook University, Tianjin University, Dalian Institute of Chemical Physics and Shanghai Jiao Tong University.

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Speeding reactions up by 10 times is a very big deal. The brain storming behind this is impressive. One can well imagine that this work will generate quite a lot more experimentation and if replications come in this good, there is sure to be some process engineering applied to industrial catalyst activity.

Argonne National Laboratory researchers have uncovered a new avenue for overcoming the performance decline that occurs with repeated cycling in the cathodes of sodium ion batteries. This discovery could find applications in batteries for transportation and the electric grid.

Battery-powered vehicles have made a significant dent in the transportation market. But that market still needs lower cost batteries that can power vehicles for greater ranges. Also desirable are low-cost batteries able to store for the grid the intermittent clean energy from solar and wind technologies and power hundreds of thousands of homes.

To meet those needs, researchers around the world are racing to develop batteries beyond the current standard of lithium-ion designs. One of the more promising candidates is the sodium-ion battery. It is particularly attractive because of the greater abundance and lower cost of sodium compared with lithium. What’s more, when cycled at high voltage (4.5 volts), a sodium-ion battery can greatly increase the amount of energy that can be stored in a given weight or volume. However, its fairly rapid performance decline with charge-discharge cycling has stymied commercialization.

Cross-section SEM image of the strained O3 NaNi0.4Mn0.4Co0.2O2. Image Credit: Argonne National Laboratory. Click image for the largest view.

Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have discovered a key reason for the performance degradation: the occurrence of defects in the atomic structure that form during the steps involved in preparing the cathode material. These defects eventually lead to a structural earthquake in the cathode, resulting in catastrophic performance decline during battery cycling. Armed with this knowledge, battery developers will now be able to adjust synthesis conditions to fabricate far superior sodium-ion cathodes.

The team published their research in Nature Communications in an article entitled, “Native lattice strain induced structural earthquake in sodium layered oxide cathodes.”

Key to making this discovery was the team’s reliance on the world-class scientific capabilities available at Argonne’s Center for Nanoscale Materials (CNM) and Advanced Photon Source (APS), both of which are DOE Office of Science user facilities.

Guiliang Xu, assistant chemist in Argonne’s Chemical Sciences and Engineering division said, “These capabilities allowed us to track changes in the atomic structure of the cathode material in real time while it is being synthesized.”

During cathode synthesis, material fabricators slowly heat the cathode mixture to a very high temperature in air, hold it there for a set amount of time, then rapidly drop the temperature to room temperature.

Yuzi Liu, a CNM nanoscientist said, “Seeing is believing. With Argonne’s world-class scientific facilities, we do not have to guess what is happening during the synthesis.” To that end, the team called upon the transmission electron microscope in CNM and synchrotron X-ray beams at the APS (at beamlines 11-ID-C and 20-BM).

Their data revealed that, upon rapidly dropping the temperature during material synthesis, the cathode particle surface had become less smooth and exhibited large areas indicating strain. The data also showed that a push-pull effect in these areas happens during cathode cycling, causing cracking of the cathode particles and performance decline.

Upon further study, the team found that this degradation intensified when cycling cathodes at high temperature (130° Fahrenheit) or with fast charging (one hour instead of 10 hours).

Khalil Amine, an Argonne Distinguished Fellow noted, “Our insights are extremely important for the large-scale manufacturing of improved sodium-ion cathodes. Because of the large amount of material involved, say, 1000 kilograms, there will be a large temperature variation, which will lead to many defects forming unless appropriate steps are taken.”

Earlier research by team members had resulted in a greatly improved anode. “Now, we should be able to match our improved cathode with the anode to attain a 20% – 40% increase in performance,” said Xu. “Also important, such batteries will maintain that performance with long-term cycling at high voltage.”

The impact could result in a longer driving range in more affordable electric vehicles and lower cost for energy storage on the electric grid.

In addition to Xu, Liu and Amine, authors include Xiang Liu, Xinwei Zhou, Chen Zhao, Inhui Hwang, Amine Daali, Zhenzhen Yang, Yang Ren, Cheng-Jun Sun and Zonghai Chen. Zhou and Liu performed the analyses at CNM while Ren and Sun did the analyses at APS.

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This news is sure to trigger some process engineering innovation., Sodium does offer enough of a leap in potential to knock lithium ion off the market top. But lets not get into expectations just yet. There are other issues to work out and lithium ion has a couple of decades of refinements already done. Getting to market isn’t going to be easy.

Texas A&M University scientists use quantum methods to predict Lithium-metal (Li-metal) batteries great potential for packing more significant amounts of energy than the current lithium-ion batteries.

For example, a Li-metal electric battery in a car could travel more miles, and a Li-metal phone battery could have longer battery life. However, the metal surface of Li-metal batteries is highly reactive, and there is limited understanding of the chemistry of these reactions.

Lithium metal foil for building batteries. Image Credit: International Tin Association. Click image for the largest view.

Dr. Perla Balbuena, professor in the Artie McFerrin Department of Chemical Engineering at Texas A&M University, is using quantum chemical methods to track specific reactions that occur on the surfaces inside Li-metal batteries. Understanding Li-metal battery reactions and predicting products will enhance usability by decreasing their reactivity.

The research was recently published in the American Chemical Society’s ACS Applied Materials & Interfaces journal and was co-authored by graduate student Dacheng Kuai from the Department of Chemistry at Texas A&M.

Balbuena said, “We need to understand what type of reactions happen, how to slow down the reactions, what the components are, what the morphology of the evolving products is and how the ions and electrons move through the surface. Understanding these critical issues will allow us to commercialize Li-metal batteries in the near future.”

When Li-metal batteries are manufactured, a thin film forms on the anode, commonly referred to as solid-electrolyte interphase (SEI). This film is made of multiple components and produced by electrolyte decomposition. The chemical makeup of the SEI is critical for ensuring peak performance from the battery and extending its lifespan. Through experimental efforts, theoretical predictions can reveal the details in this phenomenon at the atomistic and electronic levels.

In this study, the researchers targeted a polymer that develops due to electrolyte reactions on the battery’s internal surfaces. Pinpointing this specific polymer reaction is challenging but necessary to optimize the SEI. The researchers simulated the interface at the atomistic level and solved accurate quantum chemical equations to map a time evolution of the polymer formation reaction.

Balbuena explained, “What differentiates this research is starting from the microscopic-level description and letting the system evolve according to its electronic redistribution upon chemical reaction. There are many experimental techniques that can follow and monitor the reactions, but they’re challenging. With this simulation, we can get new insights. We isolate the part of the system that is responsible for important chemical events. We follow that specific group of molecules and analyze the reactions spontaneously occurring at the surface of electrodes.”

Unique to this research, the computational tools used can determine the minimum energy configurations and the arrangement of the molecules during the reaction, thus charting the reaction from beginning to end.

The researchers found that the species polymerizing in the SEI could be beneficial for Li-metal batteries because they can aid in controlling the level of reactivity of the battery materials.

Balbuena said, “We are pleased about the results, as they provide insight into what could happen when using real electrodes.”

These findings illustrate the use of computational tools that can contribute to creating batteries that are more friendly to the environment, have longer lifespans and are cheaper to produce. As better chemistries evolve, Balbuena hopes the methodologies found in her research will be helpful for years to come.

“This research can be a driving force for batteries in a greener, more efficient direction,” she added. “I know that this work will be helpful 10 years from now because 10 years ago, we made our initial contributions on Li-ion batteries and our findings helped on the development of today’s successful technology. It is a cycle of continuous improvement.”

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This is a classic example of fundamental research. One doesn’t often see work about the arrangement of molecules, the reaction process from beginning to end and the energy inputs – all in one. One just expects and hopes that the computational result are borne out in real experiments that lead to better consumer products.

University of Colorado Boulder researchers have developed a new tool that could lead to more efficient and cheaper technologies for capturing heat-trapping gases from the atmosphere and converting them into beneficial substances, like fuel or building materials.

The scientists described their technique in a paper published this month in the journal iSCIENCE.

The method predicts how strong the bond will be between carbon dioxide and the molecule that traps it, known as a binder. This electrochemical diagnosis can be easily applied to any molecule that is chemically inclined to bind with carbon dioxide, allowing researchers to identify suitable molecular candidates with which to capture carbon dioxide from everyday air.

Oana Luca, co-author of the new study and assistant professor of chemistry said, “The Holy Grail, if you will, is to try to inch toward being able to use binders that can grab carbon dioxide from the air [around us], not just concentrated sources. Determining the strength of binders allows us to figure out whether the binding will be strong or weak, and identify candidates for future study for direct carbon capture from dilute sources.”

The goal of carbon capture and storage technology is to remove carbon dioxide from the atmosphere and store it safely for hundreds or thousands of years. But while it has been in use in the U.S. since the 1970s, it currently captures and stores a mere 0.1% of global carbon emissions annually. To help meet carbon emissions goals laid out by the IPCC, carbon capture, recycling and storage would have to rapidly increase in scale by 2050.

Current industrial facilities around the world rely on capturing carbon dioxide from a concentrated source, such as emissions from power plants. While these methods can bind a lot of carbon dioxide quickly and efficiently using large amounts of certain chemical binders, they are also extraordinarily energy intensive.

This method also is quite expensive at scale to take carbon dioxide and turn it into something else useful, such as carbonates, an ingredient in cement, or formaldehyde or methanol, which can be used as a fuel, according to Luca, fellow-elect of the Renewable and Sustainable Energy Institute (RASEI).

Using electrochemical methods instead, such as those detailed in the new CU Boulder-led study, would free carbon capture facilities from being tied to concentrated sources, allowing them to exist almost anywhere.

Being able to easily estimate the strength of chemical bonds also enables researchers to screen for which binders will be best suited – and offer a cheaper alternative to traditional methods – for capturing and converting carbon into materials or fuel according to Haley Petersen, co-lead author on the study and graduate student in chemistry.

The science of chemistry is based on a few basic facts: One, that molecules are made of atoms, and two, that they are orbited by electrons. When atoms bond with other atoms, they form molecules. And when atoms share electrons with other atoms, they form what is called a covalent bond.

Electrodes being used to activate molecular bonds. Image Credit: Haley Petersen, University of Colorado Boulder. Click image for the largest view.

Using electricity, the researchers can activate these bonds by using an electrode to deliver an electron to a molecule. When they do that to an imidazolium molecule, like they did in this study, a hydrogen atom is removed, creating a gap in a carbon atom for another molecule to want to bond with it – such as carbon dioxide.

However, carbon dioxide (CO2) is the kind of molecule that doesn’t typically like to create new bonds.

Luca explained, “It’s generally unreactive, and in order to react with it, you also have to bend it. So we’re in a chemical space that hasn’t really been probed before, for CO2 capture.”

The researchers’ method examines how good a whole family of carbenes (a specific type of molecule, containing a neutral carbon atom), that they can electrochemically generate, are at binding CO2.

Luca said, “Just by looking at very simple molecules – molecules that we can make, molecules that we can modify – we can obtain a map of the energetics for electrochemical carbon capture. It is a small leap for now, but possibly a big leap down the line.”

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This is another effort at the knife edge of CO2 research. This is key, because one has to have some CO2 to do the work offered in yesterday’s post. The press release also noted that CO2 is just rock stable and isn’t game for much reactivity, an important point to keep in mind. But progress marches on as we see this week. The probability exists that one day the knowledge will coalesce around the complimentary technologies and start making some fuel at scale.


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