lithium-ion battery – Lightsources.org

Diamond celebrates 14,000th paper – A breakthrough in lithium-ion battery research

2025/01/172025/01/17

A new understanding of the role oxygen plays could revolutionise battery development

Diamond Light Source stands as one of the leading research facilities globally, driving scientific advancements. The 14,000th paper published as a result of innovative experiments undertaken at the UK’s national synchrotron highlights the profound impact science can have in addressing the world’s most urgent challenges. A team of researchers from WMG at the University of Warwick, in collaboration with academic partners in the Faraday Institution’s Degradation and FutureCat projects, has conducted a ground-breaking study that bridges the gap between academic models and real-world battery performance.

Their work, recently published in Joule, used a trio of synchrotron techniques – Resonant Inelastic soft X-ray Scattering (RIXS), hard and soft X-ray absorption spectroscopy (XAS) – to investigate the charge compensation mechanism of lithium-ion (Li-ion) battery cathodes during high-voltage operation. This study demonstrates that oxygen plays a significant role through a metal-ligand redox process, emphasising the importance of focusing on surface passivation strategies to mitigate oxygen reactivity with electrolytes, reducing degradation and enhancing safety. By using pilot-line fabricated pouch cells, this work aligns fundamental research with commercial applications and offers crucial insights to improve energy density and cycling stability.

Challenges and Opportunities for High-Energy-Density Batteries

The global transition to a low-carbon future requires the development of low-cost, reliable and long-range electric vehicles, with Li-ion batteries playing a crucial role. However, traditional models of the electronic charge compensation mechanism in layered metal oxide cathodes are insufficient for developing next-generation batteries with increased energy density through high-voltage operation.

Prof Louis Piper explained:

When we talk about trying to increase the energy density of a battery, what that means is being able to remove as many electrons as possible, In a lithium-ion battery, Li-ions move between the anode and a cathode, releasing an equal number of electrons as current. In a commercial layered metal oxide battery, we can pull out about two-thirds of the accessible lithium ions, and therefore, two-thirds of the available electrons. That means the battery is always below its theoretical capacity, but it’s engineered that way to prevent the degradation that occurs when you pull more out. Replacing cobalt with nickel increases the practical capacity of the battery, but it pushes it closer to the point where you see accelerated degradation. Traditional models attribute charge compensation solely to transition metal oxidation, but if that’s true then why does replacing cobalt with nickel change things, and why do we have more problems with safety and oxygen loss as we increase the energy density? We need a better understanding of the metal-ligand redox process to develop safe, stable, higher performance Li-ion cells.

Innovating Battery Research with Real-World Testing

WMG is home to a Battery Scale-Up pilot facility, a suite of cell production equipment covering the full production process cell assembly and testing. It allows researchers to manufacture battery cells in a variety of different formats.

New type of battery could outlast EVs

2024/12/092024/12/09

There’s a big push underway to increase the lifespan of lithium-ion batteries powering EVs on the road today. By law, in the US, these cells must be able to hold 80% of their original full charge after eight years of operation.

However, many industry experts believe we need batteries that last decades – so that once they’re no longer robust enough for use in EVs, we can put them to use in “second-life applications” – such as bundling them together to store wind and solar energy to power the electrical grid.

Researchers from Dalhousie University used the Canadian Light Source (CLS) at the University of Saskatchewan to analyze a new type of lithium-ion battery material – called a single-crystal electrode – that’s been charging and discharging non-stop in a Halifax lab for more than six years. It lasted more than 20,000 cycles before it hit the 80% capacity cutoff. That translates to driving a jaw-dropping 8 million kms. As part of the study, the researchers compared the new type of battery – which has only recently come to market – to a regular lithium-ion battery that lasted 2,400 cycles before it reached the 80% cutoff.

“The main focus of our research was to understand how damage and fatigue inside a battery progresses over time, and how we can prevent it,” says Toby Bond, a senior scientist at the CLS, who conducted the research for his PhD, under the supervision of Professor Jeff Dahn, Professor Emeritus and Principal Investigator (NSERC/Tesla Canada/Dalhousie Alliance Grant) at Dalhousie University. The study was funded by Tesla Canada and NSERC under the Alliance grant program.

Things got very interesting, he says, when the scientists used the ultrabright synchrotron light to peer inside the two batteries. When they looked at the inner workings of the regular lithium-ion battery, they saw an extensive amount of microscopic cracking in the electrode material, caused by repeated charging and discharging. The lithium, he explains, actually forces the atoms in the battery material apart and causes expansion and contraction of the material.

“Eventually, there were so many cracks that the electrode was essentially pulverized.”

However, when the researchers looked at the single crystal electrode battery, they saw next to no evidence of this mechanical stress. “In our images, it looked very much like a brand-new cell. We could almost not tell the difference.”

Bond attributes the near absence of degradation in the new style battery to the difference in the shape and behaviour of the particles that make up the battery electrodes. In the regular battery, the battery electrodes are made up of tiny particles up to 50 times smaller than the width of a hair. If you zoom in on these particles, they are composed of even tinier crystals that are bunched together like snowflakes in a snowball. The single crystal is, as its name implies, one big crystal: it’s more like an ice cube. “If you have a snowball in one hand, and an ice cube in the other, it’s a lot easier to crush the snowball,” says Bond. “The ice cube is much more resistant to mechanical stress and strain.”

Read more on CLS website

Synchrotron light impact on battery materials during real-time analysis

2024/10/222024/10/23

A multi-centre study carried out by ALBA Synchrotron, ICMAB-CSIC, CIC energiGUNE and BRTA researchers has uncovered critical beam-induced effects in battery materials studied using synchrotron light. The team demonstrated that X-ray radiation can inhibit electrochemical activity in common lithium-ion battery electrodes during characterization studies.

The study identifies radiation dose thresholds and proposes new strategies to mitigate beam-induced effects to ensure more accurate operando battery characterization.

Efficient energy storage is critical to achieving a clean energy future, since large-scale batteries will enable the storage and distribution of renewable energy sources like solar and wind power. Global efforts to optimize battery performance include the development of new materials, which are often characterized using synchrotron-based operando techniques. These real-time measurements examine the performance of the battery as it charges and discharges. However, the potential impact of high-intensity X-ray beams on the materials under study had not been fully understood until now, raising concerns about the accuracy of results from these powerful techniques.

A new study, published in Chemistry of Materials, sheds light on this issue by systematically investigating how synchrotron radiation affects two widely used battery electrode materials based on lithium: LiNi_0.33Mn_0.33Co_0.33O2 (NMC111) and LiFePO₄ (LFP). The research reveals that the X-ray beams produced at synchrotron facilities and used in these experiments can alter the electrochemical activity of these materials, and in extreme cases, this may lead to incorrect conclusions about the performance of the materials.

Researchers from the Institute of Materials Science of Barcelona (ICMAB-CSIC), the Centre for Cooperative Research on Alternative Energies (CIC energiGUNE), the Basque Research and Technology Alliance (BRTA) and the ALBA Synchrotron collaborated to investigate the electrochemical behavior of NMC111 and LFP—two key components of commercial lithium-ion batteries—under X-ray radiation. Using X-ray Diffraction (XRD) and X-ray Absorption Spectroscopy (XAS) at the MSPD and NOTOS beamlines of ALBA, they observed how the materials reacted to different radiation intensities while undergoing charge and discharge cycles.

The results showed that at high doses, the synchrotron radiation caused a localized inhibition of the electrochemical reactivity at the irradiated areas. In other words, the X-ray beam interfered with the normal functioning of the battery material, slowing down or halting the expected chemical reactions. The effects were found to be dose-dependent, with higher radiation doses leading to more significant inhibition. Importantly, the study demonstrated that these effects were reversible. Once the beam was moved to a different area or when the radiation intensity was reduced, the materials returned to their normal activity. This suggests that the materials were not permanently damaged by the beam, but rather their activity was temporarily “paused” due to X-ray exposure.

These findings corroborate already known beam-induced effects in operando measurements with synchrotron light. Nevertheless, thanks to the systematic investigation they also enable researchers to propose several strategies to mitigate them. For example, reducing the intensity of the synchrotron beam by using attenuators, such as aluminum foils to lower the photon flux reaching the sample. The researchers also found that thinner battery electrodes were less affected by the beam, suggesting that the thickness of the materials being studied influences their radiation tolerance. Additionally, they observed that controlling the exposure time and introducing rest periods between measurements could help prevent the build-up of beam effects.

This study, the first to use the NOTOS beamline for advancing battery research, not only provided a first systematic analysis of the beam-induced effects when using synchrotron light to study materials under actual working conditions, but also has broader implications for improving the accuracy of synchrotron-based characterization techniques across many fields of materials science. As scientists work to develop new and more efficient battery materials—especially for applications like electric vehicles and renewable energy storage—synchrotron specialists around the world will continue refining high-brilliance X-ray techniques to provide accurate, real-time data for understanding the complex chemical processes that take place during battery operation.

Read more on ALBA website

RIXS Shows Why Li-rich Batteries Fade

2024/09/172024/09/20

High-resolution resonant inelastic X-ray scattering uncovers the role that oxygen plays in voltage fade in next-gen battery materials

As part of the transition to net zero, the Faraday Institution’s CATMAT (Lithium Ion Cathode Materials) project is focusing on improving lithium-ion battery energy density and electric vehicle (EV) range. Its scope includes adding to our understanding of lithium-rich (Li-rich) oxygen-redox cathodes and novel anion-chemistry cathodes, as well as developing scalable synthesis routes for these materials. As part of this project, researchers from the University of Oxford are working with Diamond’s I21 beamline to explore the cause of voltage fade in Li-rich cathodes, using high-resolution resonant inelastic X-ray scattering (RIXS) spectroscopy. In work recently published in Nature Materials, they followed the oxygen redox reaction in Li-rich cathodes over cycling and quantitatively measured the O₂ trapped within the material. Their results show that a gradual increase in electrochemically inactive O₂ and the loss of O₂ from voids near the cathode surface lead to a reduction in the O redox capacity and the observed voltage fade. These important insights could lead to innovations in cathode chemistry and aid the transition to low-carbon energy sources.

Powering net zero: understanding lithium-rich battery cathodes

The net zero transition necessary to limit the effects of climate change requires dramatic cuts to carbon emissions. One of the cornerstones of the UK’s transition will be switching to fossil-free transport, with electric vehicles (EV) one of the most developed options. However, the cathode is a critical limiting factor in efforts to increase the energy density of lithium-ion (Li-ion) batteries for EV applications. As changes to the chemistry of the cathode are likely to lead to improvements in battery performance, such as boosting battery life, storing greater energy to improve range, reducing battery cost and increasing the power available to the EV during acceleration, developing next-generation lithium-ion cathodes is a major priority. “Lithium-ion batteries are very critical to the net zero transition, enabling electric vehicles and grid storage, says Dr Robert House, at the University of Oxford.

In order to get better batteries, we need new materials which are able to store more energy in the same volume and the same mass – an increase the energy density. One of the biggest limitations is the cathode material. These typically have layered structures with alternating layers of transition metal oxide and lithium ions. The best-known cathode materials are NMCs, named for the combination of nickel, cobalt and manganese within the transition metal layer.

Dr Robert House

Lithium-rich cathodes are next-generation materials which have higher concentrations of lithium within the cathode structure, replacing some of the transition metals. They have a higher capacity because they store energy via oxidation of the oxygen in the structure as well as the transition metal. However, although these materials were first discovered over twenty years ago, a long-standing question has been how the oxygen undergoes charge storage. Dr House says:

Over the past few years, working on the CATMAT project, we’ve uncovered that the oxideoxygen anion converts to O₂ molecules, which are trapped within the crystal structure of the cathode. And this discovery of the exact nature of the oxygen was first made possible by using high resolution RIXS on the I21 beamline.