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The end of EV tax credits? RASEI Fellow Stephanie Weber explains what's at stake

Daniel Morton — Mon, 15 Sep 2025 15:42:27 +0000

The end of EV tax credits? RASEI Fellow Stephanie Weber explains what's at stake Daniel Morton Mon, 09/15/2025 - 09:42

September 2025

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Fixing Solar’s Weak Spot: Why a tiny defect could be a big problem for perovskite cells

Daniel Morton — Mon, 15 Sep 2025 15:25:36 +0000

Fixing Solar’s Weak Spot: Why a tiny defect could be a big problem for perovskite cells Daniel Morton Mon, 09/15/2025 - 09:25

Daniel Morton

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Solar energy is a crucial part of our clean energy future, but a new, highly efficient solar material has a hurdle that needs to be addressed. A recent study reveals how a microscopic weak spot can lead to total device failure and what we can do about it.

A collaboration between a team led by RASEI Fellow Mike McGehee and scientists at the National Renewable Energy Laboratory (NREL), just published in the scientific journal Joule, provides evidence to help solve one of the key hurdles to large-scale manufacture of next generation perovskite solar cells.

Imagine you have a series of hoses connected end-to-end to water your garden. The water flows from the faucet, through each hose, and out the last nozzle. When every hose is getting enough water, the flow is strong and steady. This is like how a string of solar cells works on a solar panel; the sun’s energy makes electrons (the “water”) that flow through each cell, creating electricity.

But what happens if a single section of the hose gets kinked? The water can’t flow through it anymore, but there is still a lot of pressure coming from the faucet. The pressure will build up and eventually burst the weak spot in the kinked section. This is analogous to what happens when a section of the solar panel is shaded --- the cell becomes ‘kinked’. When just one part of a panel is shaded, the unshaded cells still generate electricity and “force” current backward through the non-producing shaded cell. This is known as reverse bias, and it can cause the shaded cell to permanently degrade and fail.

For conventional silicon-based solar cells, reverse bias is a known problem and engineers have developed a solution: a bypass diode. You can think of this as a small side-channel that allows the water to flow around the kinked hose, keeping the rest of the system running smoothly without building up damaging pressure.

However, the bypass diode solution doesn’t work for perovskite-based solar cells, a leading candidate for the next generation of more efficient and more affordable solar cells, because they are often too “weak”. One of the key pieces in the puzzle to solving this reverse bias problem in perovskite solar cells is understanding how the cell degrades when under reverse bias, and that is the focus of this research collaboration.

The McGehee group has a long history of success in creating and optimizing perovskite solar cells. Beginning in 2018, their focus shifted to a critical challenge: what happens when these cells are in the shade? Many researchers had already observed that even a small amount of reverse bias caused the materials to heat up and "melt," leading to rapid and permanent degradation of the perovskite.

While these observations were widely accepted, the exact reason for the degradation was a mystery and a subject of much debate. "These are complex systems, and it can be very hard to untangle what is going on," explained Ryan DeCrescent, one of the study's lead researchers. This is where the McGehee group's work came in—they set out to find the specific mechanism behind this destructive behavior.

"These are complex systems, and it can be very hard to untangle what is going on," explained Ryan DeCrescent

The perovskite layer is formed through an approach called solution processing. Solution processing is kind of like making a pancake, you make your batter and when you pour it onto a hot griddle several things happen: the water evaporates, the solids set, the thickness is determined by how much you add, and you often get gaps, or holes in your pancake. In these devices, the perovskite ingredients are put into a solvent. The solvent is then dropped onto the earlier layers of the device and warmed up, whereby the solvent evaporates and a film is formed, but often with defects, or gaps. Defects and pinholes are easily formed in such films. This is a particular issue for perovskites, since the precursor solution has low viscosity and during the heating stage defect formation is common.

To better understand the impact of these defects on the performance of the solar cells under reverse bias you need to take a really good look at them. Central to this work is a suite of tools that enabled exceptional examination of the perovskite layer. “A large part of this work was really setting ourselves up to look very carefully at these surfaces” said DeCrescent. Four main techniques were employed to better understand the defects: Electroluminescence (EL) imaging with a high-resolution camera, Scanning Electron Microscopy (SEM), Laser-Scanning Confocal Microscopy (LSCM) and Video Thermography. The strategy was to compare ‘before, during, and after’ pictures of devices that had been exposed to reverse bias. The high-resolution camera showed that “weak spots” in the device were the origin of degradation. To better understand “perfect” device behavior and efficiently scan a large number of samples (~100), the team setup a large number of very small devices, creating thin films with an area of just 0.032 mm^2. To put that in perspective, each device was about the width of two human hairs. The small size of these devices meant that it was possible to create devices that were defect-free, since it is hard to create defect-free films on a larger scale. Through this combination of a large sample size, and advanced imaging, the team was able to rapidly explore many different types of defects.

This approach of using advanced imaging proved to be an incredibly effective way not only to identify the defects but also to understand exactly what happens to them. "Video thermography and electroluminescence imaging are really powerful techniques for such devices; for example, defects that are sometimes difficult to spot really stand out using these approaches," explained Ryan. Using the thermography technique the defects glow brightly, and in the electroluminescence technique the defects show as dark. Using these techniques in combination provided a very reliable and effective way of mapping the defects. The techniques clearly revealed where the degradation was occurring.

The team’s evidence strongly supports the argument that defects, like pinholes and thin spots in the perovskite layer, are the precise locations where reverse-bias breakdown begins. The thermography images showed that these sites are where the material rapidly heats up and melts, essentially shorting between the two contact layers. In contrast, defect-free devices showed remarkable stability, surviving hours of reverse bias without any significant degradation.

This level of detailed understanding is crucial for the future of this technology. The team's research provides a clear path forward for scientists and engineers: to develop more robust and stable perovskite solar cells, they must prioritize making pinhole-free films and using more robust contact layers to prevent this kind of abrupt and permanent thermal damage.

This work represents a critical step in the journey toward commercializing perovskite solar cells. It highlights the fact that detail-driven, rigorous scientific approaches are needed to understand complex problems. With this knowledge in hand, scientists can now engineer devices that are designed for longevity, ensuring these promising materials can fulfill their potential.

September 2025

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��Ҵ�ý�ƽ�� Faculty Leadership Institute welcomes RASEI Fellow to 2025 Cohort

Daniel Morton — Thu, 11 Sep 2025 18:07:13 +0000

��Ҵ�ý�ƽ�� Faculty Leadership Institute welcomes RASEI Fellow to 2025 Cohort Daniel Morton Thu, 09/11/2025 - 12:07

Daniel Morton

RASEI Fellow Srinivas Parinandi has been selected, along with 14 others, as a member of the 2025 Cohort of the ��Ҵ�ý�ƽ�� Faculty Leadership Institute.

The ��Ҵ�ý�ƽ�� Faculty Affairs Institute, (FLI), established in 2013, is a program that helps identify, foster, and support emerging leaders as they prepare to further their leadership trajectory. Now with over 150 Fellows, each cohort (typically ~12-15 members each year), has the opportunity to engage with campus leaders in targeted discussions around current campus issues and build leadership skills. Monthly meetings throughout the academic year provide focus on two main areas of impact:

Meetings with campus leadership
Leadership skill development

This year RASEI Fellow Srinivas (Chinnu) Parinandi was selected to the cohort. Srinivas is an Associate Professor in the Political Science Department at ��Ҵ�ý�ƽ��. Research in the team explores American Political Institutions with a focus on two main areas; how the design of regulation influences policy outcomes; and how institutional characteristics condition the spread, or diffusion, of policy. The primary emphasis of his work looks at energy and economic policy.

September 2025

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Building Energizing Connections: Front Range Researchers Unite

Daniel Morton — Wed, 10 Sep 2025 16:33:38 +0000

Building Energizing Connections: Front Range Researchers Unite Daniel Morton Wed, 09/10/2025 - 10:33

Daniel Morton

This August (18-19, 2025), the Front Range came alive with scientific collaboration as the 2025 Front Range Electrochemistry Workshop (FREW) brought together over 100 researchers from across the region. Hosted at ��Ҵ�ý�ƽ��'s Sustainability, Energy, and Environment Community (SEEC) building, this two-day gathering showcased the power of regional partnership in tackling some of our most pressing energy challenges. The workshop was funded by NSF’s Institute for Data Driven Dynamical Design.

Find out more about the workshop

Front Range Electrochemistry Workshop

What is Electrochemistry and Why Does It Matter?

Electrochemistry might sound complex, but it's essentially the science of using electricity to drive chemical reactions—and it's at the heart of our clean energy future. Think of the battery in your phone or car, the fuel cells powering some buses, or emerging technologies that can capture carbon dioxide from the air and turn it into useful materials. All of these rely on electrochemical processes that researchers are working to improve and expand.

Regional Collaboration

The Front Range is developing as a hub for this critical research. This workshop exemplified that spirit, bringing together researchers from Colorado School of Mines, ��Ҵ�ý�ƽ��, Colorado State University, the University of Wyoming, and several National Laboratories to share ideas, forge new partnerships, and identify opportunities for joint research.

"It was a really great meeting, with participants bringing an excited and motivated attitude that made for a really fantastic atmosphere," noted RASEI Fellow Mike Toney, who served on the organizing committee. The participants generated a great atmosphere at the workshop as researchers moved between presentations, interactive poster sessions, and innovative "collaboration pitch" sessions designed specifically to spark new partnerships, especially among graduate students. “The poster session was a great experience. I really enjoyed sharing my sodium-ion battery research and was exposed to a lot of fresh ideas across the electrochemistry space from other students and speakers” explained Loren Andrews, a Graduate Student at ��Ҵ�ý�ƽ��.

Tackling Real-World Challenges Together

The workshop covered a diverse range of applications that could transform how we store and use energy:

Advanced Battery Technologies: Improving today's lithium-ion batteries and developing next-generation alternatives, including solid-state batteries that could be safer and more efficient
Grid-Scale Energy Storage: Exploring redox flow batteries that could store renewable energy for entire communities
Clean Transportation: Advancing fuel cell technology for cars, trucks, and other applications
Sustainable Chemical Manufacturing: Developing electrochemical processes to catalyze chemical transformations
AI-Powered Discovery: Using machine learning to accelerate the development of new materials and processes

Using Interactive Approaches to Develop Connections

What made this workshop particularly engaging was the opportunity to connect across different institutes along the Front Range region. The interactive format encouraged researchers to step out of their individual labs and think collectively about connected strengths and opportunities. Rather than just have lecture style presentations, the organizers developed a mixed schedule. The poster sessions weren't just about presenting results, they were also networking opportunities. The pitch sessions weren't just about sharing ideas, they were also about identifying concrete ways to work together.

To incentivize participation and develop some friendly competition in th poster and collaborative pitch sessions the organizers were able to offer a prize structure. For the poster session Abby Cardoza (Colorado School of Mines) won first place and Loren Andrews & Peter Romero (��Ҵ�ý�ƽ��) won second place. For the Pitches a team with Cindy Wong (��Ҵ�ý�ƽ��), Colby Evans (NIST), Emily Hansen (Colorado School of Mines), and Olajide Aijbade (University of Wyoming) took first place, and second place went to a team including Rebecca Beswick (��Ҵ�ý�ƽ��), Peter Romero (��Ҵ�ý�ƽ��), Bryce Rives (��Ҵ�ý�ƽ��) Chris Sedmak (Colorado School of Mines), Matt Hammel (Colorado School of Mines). Congratulations to everyone!

The success of this workshop provides an opportunity for the regional electrochemistry community. Future gatherings will help to strengthen these collaborative connections and accelerate research

In a time where large scientific challenges are increasingly complex, events like this demonstrate how regional collaboration can be a powerful catalyst for innovation—bringing together diverse expertise, building new partnerships, and fostering new ideas.

August 2025

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Liquid Crystals that Keep Time: Scientists Create Matter that Dances to Its Own Beat

Daniel Morton — Fri, 05 Sep 2025 19:29:45 +0000

Liquid Crystals that Keep Time: Scientists Create Matter that Dances to Its Own Beat Daniel Morton Fri, 09/05/2025 - 13:29

Adapted from an article run in ��Ҵ�ý�ƽ�� Today by Daniel Strain

A team led by RASEI Fellow Ivan Smalyukh has discovered a new type of liquid crystal that exists in perpetual, rhythmic motion, creating, for the first time, time crystals visible to the naked eye.

Reporting their findings in Nature Materials, the team demonstrates how liquid crystals, the same materials found in your phone display, can form a phase of matter that spontaneously breaks both space and time symmetries. Unlike previous time crystals that existed only in quantum systems invisible to the naked eye, these can be observed directly under a microscope.

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��Ҵ�ý�ƽ�� Today Highlight

Phys.Org Highlight

Bioengineer.Org Highlight

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Gizmodo Highlight

The researchers designed special glass cells filled with liquid crystals and coated with light-sensitive dye molecules. When illuminated with blue light, something remarkable happens: like dancers following a lead, the liquid crystal molecules respond to cues from the dye molecules, creating an elaborate molecular waltz that repeats its steps over and over.

Here's how the molecular choreography works: The azobenzene dye molecules at the surface respond to light by rotating, which then guides neighboring liquid crystal molecules to reorient. This creates a feedback loop where the changing liquid crystal orientation affects how light polarizes as it passes through, which then influences more dye molecules at the bottom surface. The result is a self-sustaining temporal rhythm.

The researchers discovered that these time crystals are built from special molecular arrangements called ‘topological solitons’, think of it like stable whirlpools in a stream that maintain their shape while the water flows around them. These soliton "particles" interact with each other through the liquid crystal's elasticity, forming arrays that oscillate in time with remarkable precision.

What makes these time crystals remarkable is their resilience, similar to a heartbeat that continues despite disturbances, these patterns persist even when perturbed. The team demonstrated that the crystals maintain their rhythm when subjected to random light fluctuations and recover their ordered state after disruptions, meeting stringent criteria that distinguish true time crystals from simple periodic behavior.

The temporal periods can be tuned from milliseconds to tens of seconds by adjusting temperature and light intensity, while the spatial patterns can extend over areas larger than a square millimeter—making them easily visible and potentially practical for applications.

There are many potential applications, particularly in optoelectronics and security. The time crystals could serve as dynamic optical elements that modulate light in both space and time, enable new forms of optical communication, or provide sophisticated anti-counterfeiting features through their unique spatiotemporal "fingerprints." The ability to create 2+1 dimensional barcodes (two spatial dimensions plus time) could revolutionize information storage and encoding.

As is often found with breakthrough discoveries, the most transformative applications are likely yet to be imagined. But for now, scientists have created matter that literally keeps time.

September 2025

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Effective and sustainable energy storage is critical to a modern and resilient power grid. Independent of how the electrons are generated, the ability to flexibly store and supply electricity strengthens the grid and improves our energy security.

The path to a reliable and sustainable energy economy runs directly through better, more efficient batteries. Today’s power grid demands storage solutions that are more efficient, built from materials that are abundant, affordable and environmentally responsible. This intersection of performance and sustainability presents one of the most exciting tensions in modern energy research.

In the last six months RASEI Fellows have publish more than ten research articles that explore a range of materials science challenges associated with battery storage, developing solutions at the molecular level that could have profound impacts on how we store energy on the grid-scale, here we highlight a selection of this recent work.

Why Batteries Are Essential For Grid Flexibility

Battery storage offers exceptional flexibility to a modern power grid, providing rapid response capabilities that can balance supply and demand within seconds rather than minutes or hours. A key benefit of battery systems is that they can be deployed virtually anywhere, from urban centers to remote locations, creating opportunities for more resilient and distributed grids that adapt to local needs and conditions.

Materials Science Engineering Charges Innovation

At its core, battery performance is fundamentally about engineering better materials: how molecules are structured, how electricity flows, and how charged particles travel through carefully designed and engineered structures. This is where cutting-edge materials science research is essential, providing the tools to better design battery components at the molecular scale to achieve faster charging, longer lifespans, and higher energy storage. These are features that will be critical as we scale up to grid-level storage.

Consider how a typical rechargeable battery, such as a lithium-ion battery, works: charged particles (such as lithium ions) move between the two sides of the battery during charging and discharging. Think of it like cars moving between parking lots (the two sides of the battery, the positive and negative electrodes). The ability to park more cars represents the ability to carry more energy. When you use the battery the cars (the lithium ions) travel between the lots through a highway (the electrolyte). To use the highway, they have to pay a toll. In this case they give up an electron, which produces the electricity that powers your device. When you charge the battery the cars move back to the original lot, but you have to give them an electron to go back through the toll.

Repeated charging and discharging can cause damage to the parking lots, the highway between them, and the cars can even get stuck. Building better electrodes (parking lots), more effective electrolytes (the highway) and better understanding of how the charged particles act (the cars), teams can develop more effective and robust energy storage.

Recent Research Highlights

Boron-Alloyed Silicon Nanoparticle Anodes can improve the performance for lithium-Ion Batteries.

Read the article here

By mixing some boron with your silicon you can make a more robust battery electrode!

With a theoretical energy density ten times higher than graphite, Silicon (Si) has inspired interest as a next generation anode active material for lithium-ion batteries. In the general analogy, this is building a more robust parking lot for the charged state. When you charge and discharge a lithium-ion battery, on a molecular scale this is achieved by the pumping in, and pumping out of lithium ions (cars going in and out of the parking lot), which come with a significant volume change. (This would be like the floors of a multi-story parking lot changing size as cars drive in and out. Realistic on the atomic scale, not so much on the car-scale…) Silicon-based anodes have been found to be unstable to this constant change in volume which can lead to instability and failure. One strategy to address this is to move from having the silicon anode being a solid slab, to being a series of nanoparticles, which helps to reduce this mechanical stress, but this comes with another problem, the increased surface area of the particles allows more chemical side reactions, which is another big problem. There has been much research investigating the materials science and surface chemistry to reduce the unwanted side reactions. A key finding from recent research is that the best way to prevent unwanted side reactions is to essentially isolate the silicon surface from the electrolyte media it is in. This is where this research, led by RASEI Fellow Nate Neale, comes in.

By mixing, or alloying, the silicon with boron, the anodes were found to perform better and last longer. The more boron added to the nanoparticles, the more robust they were. In fact, the team saw a 3x improvement in lifetime by incorporating boron. The team proposes that by making the nanoparticles out of a mixture of silicon and boron, the presence of the boron creates an “electric double layer” effect, essentially providing a protective layer at the surface of the nanoparticle, shielding from the unwanted side reactions. This saw some real improvements in the performance of the electrolytes, not just a 3x improvement in the calendar lifetime, but an 82.5% capacity retention after 1000 cycles, the pure silicon electrodes reached the end-of-life (<80% capacity retention) in fewer than 400 cycles under similar conditions.

Boron creates a strong electrical field at the nanoparticle surface that attracts and concentrates ions from the surrounding electrolyte, forming a stable, dense layer that acts like a permanent shield. This work reveals an underexplored parameter in the design and optimization of silicon anodes that could prove valuable in the next-generation of lithium-ion batteries.

This breakthrough could accelerate the adoption of silicon anodes in battery applications, such as electric vehicles, where longer-lasting batteries are essential to address range anxiety. The research team is now working to identify the optimal silicon-boron ratio that maximizes both capacity and longevity, potentially bringing us closer to the next generation of high-performance lithium-ion batteries.

How Molecular Shape Impacts Battery Performance: New Insights for Flow Batteries

Read the article here

Making seemingly minor molecular changes to the structure of charge storage chemicals can have significant impacts on the performance of redox flow batteries.

Redox Flow Batteries offer a promising solution for large-scale energy storage. Unlike the lithium-ion batteries in your phone, flow batteries store energy in liquid electrolytes that flow through the system. This design allows them to store massive amounts of energy for long periods, making them ideal for stabilizing electrical grids.

However, making these batteries practical requires finding the right chemical compounds that are stable, efficient, and cost effective. This article describes collaborative research that includes teams led by RASEI Fellow Mike Toney and former RASEI Fellow Mike Marshak. The teams were exploring the optimization of chromium-based compounds as charge carriers. The aim was that by changing the structure of the organic chelate ligand that surrounds the chromium atom, they could better understand the relationship between structure and performance and use that understanding to design more efficient systems.

Two very similar chromium compounds were prepared; CrPDTA and CrPDTA-OH, which differ only by the addition of a single hydroxyl group (-OH) on the organic framework. Hydroxy groups are often added to compounds to improve their solubility in water, but in this case the team observed a drop in the performance of the molecule. The hydroxylated compound showed:

Slower reaction rates – The CrPDTA-OH transferred electrons 100 times more slowly than the non-hydroxylated.
Reduced efficiency – battery efficiency dropped from 99.3% to 98.2%.
Increased hydrogen gas production – more energy was wasted producing unwanted hydrogen gas in a side reaction instead of being stored.

It’s kind of like if some of the cars had one flat tire. They are going to be worse at transporting charge back and forth, and they might do things you don’t want them to.

Using a suite of advanced characterization techniques the team discovered that the addition of the hydroxyl group caused a distortion of the molecular shape around the central chromium ion. This distorted shape weakened the bonds between the metal atom and the organic chelate ligand, which reduced the efficiency of electron transfer.

This research reveals a fundamental principle for designing redox flow battery materials: molecular geometry matters immensely. The chromium atom needs to adopt an octahedral arrangement to work efficiently. Any distortion of this shape leads to reduced performance. This study also confirms why maintaining the precise structure is so important. It prevents water molecules from interfering with the chromium atom, which would cause the unwanted production of hydrogen gas instead of energy storage.

Researchers Discover The Hidden ‘Dance’ Of Ions That Could Inform The Design Of Grid-Scale Energy Storage

Read the article here

Insights into the processes of charge movement in the electrolyte could inform future battery design

The electrolyte of the battery is the highway that connects the two parking lots together. This research that brings together an international collaborative team, including researchers from three US universities, three National labs, and researchers from the United Kingdom and Switzerland, and RASEI Fellow Mike Toney, reveals important features of this highway in zinc-ion based batteries.

While most people are familiar with lithium-ion batteries in their phones and devices, zinc-ion batteries offer compelling advantages for large-scale electricity storage. Zinc is more abundant and thus affordable, zinc-ion batteries use water-based electrolytes that are much less likely to overheat or explode, Zinc-ion batteries can pack a lot of energy into a small space, they are very energy dense.

The electrolyte is the media through which the charged ions pass through during charge and discharge cycles. In our metaphor the electrolyte is the highway on which the cars travel back and forth. The properties of the electrolyte can dictate a number of features of the batteries performance, how fast it charges, how long it lasts, and how much energy it can store. This research has explored how these ions, or ‘cars’, act during transport, and they have observed that it is not plain driving, the ions cluster and form convoys as they move through the electrolyte. The way the zinc sulfate ions travel is far more dynamic and complex than previously understood.

Using advanced x-ray techniques in combination with advanced computer modeling the team were able to explore the molecular structure of the electrolyte at different stages of the charge / discharge cycle. They found that the ions don’t just float around independently, instead they form clusters, like cars forming a convoy. It was observed that the zinc ions surround themselves with exactly six water molecules and clusters formed in a range of sizes, from just 2 ions all the way up to 22 ions.

You might expect that they clusters would move more slowly, like a traffic jam on the highway, but the team found that while the clusters do reduce conductivity, the battery still works. Critical to this is the timing of the clusters. The clusters are incredibly short lived, existing for only picoseconds (trillionths of a second) at a time. Instead of having a traffic jam, it is like having really busy traffic that is moving so fast that it is constantly reorganizing itself and so it never actually gets stuck.

This offers insights that can be applied in future battery designs; Ions form diverse, temporary partnerships that vary in size and composition, the system is constantly undergoing reorganization, transport happens both through vehicular motion (cars moving through the highway), and hopping between clusters (it would be like someone jumping from car to car in an action movie). These insights could improve future electrolyte design which could improve battery performance and potentially open the door to new battery chemistries that could be used for a broader range of applications, such as grid-scale storage.

By developing a more informed understanding of how charge is transported in electrolytes we can improve our designs in the future. Instead of trying to avoid cluster, we can harness it to improve the efficiency of charge transport in battery technologies.

Inside the battery: X-Ray Vision Reveals How Sodium Really Moves and Stores Energy

Read the article here

Sodium-ion batteries have the potential to be game changers for grid-scale storage with their abundance, low cost, and sustainability advantages over existing lithium-ion technologies. A key hurdle in their development is that we don’t yet fully understand how sodium actually moves and stores energy on the molecular level. This international collaboration, led by RASEI Fellow Mike Toney, uses cutting-edge X-ray techniques and computational modeling, provides insight into these promising battery chemistries.

Sustainable battery technologies are central to the modern power grid and meeting the growing demand of electrification technologies, such as electric vehicles. Among the growing array of battery chemistries Sodium-Ion Batteries (NIBs) address many of the challenges associated with lithium-ion batteries, and can even benefit from the work done to bring lithium-ion technologies to scale. This is swapping out the cars in our analogy from lithium-ions to more affordable sodium-ions. Sodium is one of the most abundant elements on Earth, making it dramatically more affordable and sustainable than lithium. While NIBs don’t yet match the energy density of lithium-ion based designs, they are ideal for grid storage applications where space is less constrained, but cost and sustainability matter enormously. Furthermore, NIBs can be produced using lithium-ion manufacturing facilities, enabling rapid deployment without the associated infrastructure costs.

The main hurdle has been developing anode materials that efficiently store and release sodium ions. Hard carbon shows promise but understanding exactly how sodium storage works at the molecular level remained elusive—a critical gap for large-scale manufacturing.

This research uses a combination of advanced X-ray spectroscopy techniques and computational modeling to peer inside the electrodes of a working NIB to watch the storage process unfold in real-time. Put simply they explored the details of a three step system where sodium ions first attach to surface defects in the hard carbon, then squeeze between the carbon layers, and finally cluster into the pores of the anode, providing insights and a road map for the design of NIBs in the future.

To gain more information about the details of these processes the team using X-ray total scattering, a technique that bounces high-energy X-rays off atoms and analyzes the scattered pattern to map exactly where atoms are positioned relative to each other. Think of it like echolocation to see in the dark, but for atomic structures! By taking a series of ‘snapshots’ of the NIBs at different stages of charging, the researchers could track how sodium atoms moved and arranged themselves during the process. The X-ray data reveals amazing levels of detail, revealing distinct signatures for different types of sodium storage, distinguishing between sodium atoms stuck to the surface defects of the hard carbon and those squeezed between carbon sheets, and those atoms clustered in pores.

Through a combination of these experimental results and advanced computational modeling the team were able to piece together a three-stage sequence to better understand the movement of sodium ions during charging. First, the sodium ions target high-energy defect sites on the hard carbon surfaces, like easy to access parking spots with the strongest attraction. In the second stage, as the prime parking spots fill up, sodium begins what the researchers call “defect-assisted intercalation’, where the defects are used as entry points to slip between the carbon layer (like cars going to other levels of a multistory parking lot), causing the carbon layers to expand slightly. In the third stage, in the low-voltage plateau region, sodium continues to intercalating between the layers, while also filling up the nanoscale pores and forming metallic clusters. Crucially the evidence from the X-ray analysis shows that the size of these clusters is dependent on the pore size – larger pores in the carbon processed at higher temperatures produced bigger sodium clusters, directly linking the battery’s microstructure to its storage capacity.

This molecular-level understanding has the potential to transform NIB development from educated guesswork into precision engineering. Guided by this three stage roadmap, battery researchers can now strategically design hard carbon materials, altering defect concentrations to optimize initial storage, controlling pore sizes to maximize capacity, while balancing these factors to minimize the irreversible trapping that reduces overall battery lifetimes. The combined X-ray spectroscopy and computational modeling technique demonstrated in this research has the potential to provide a powerful new toolkit for studying other battery chemistries in the future. By revealing more about how sodium energy storage works, this research brings us closer to sustainable solutions for grid-scale energy storage, a critical piece in the puzzle for a modern, resilient, and sustainable energy economy.

August 2025

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The end of EV tax credits? RASEI Fellow Stephanie Weber explains what's at stake

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Fixing Solar’s Weak Spot: Why a tiny defect could be a big problem for perovskite cells

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���Ҵ�ý�ƽ������ Faculty Leadership Institute welcomes RASEI Fellow to 2025 Cohort

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Building Energizing Connections: Front Range Researchers Unite

What is Electrochemistry and Why Does It Matter?

Regional Collaboration

Tackling Real-World Challenges Together

Using Interactive Approaches to Develop Connections

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Liquid Crystals that Keep Time: Scientists Create Matter that Dances to Its Own Beat

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RASEI Fellow Bri-Mathias Hodge selected as member of the 25th Excellence in Leadership Cohort

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Powering the Future: U.S. Students Gain International Experience Through Photovoltaics Research in Berlin

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RASEI Fellow Gregor Henze featured in CBS News Article on Energy Efficient AC use

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Autonomous Research for Real-World Science Workshop: AI Could Help Bridge Valley of Death for New Materials

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Breakthroughs in materials science are helping to improve tomorrows energy storage

Why Batteries Are Essential For Grid Flexibility

Materials Science Engineering Charges Innovation

Recent Research Highlights

Boron-Alloyed Silicon Nanoparticle Anodes can improve the performance for lithium-Ion Batteries.

How Molecular Shape Impacts Battery Performance: New Insights for Flow Batteries

Researchers Discover The Hidden ‘Dance’ Of Ions That Could Inform The Design Of Grid-Scale Energy Storage

Inside the battery: X-Ray Vision Reveals How Sodium Really Moves and Stores Energy

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��Ҵ�ý�ƽ�� Faculty Leadership Institute welcomes RASEI Fellow to 2025 Cohort