X-rays provide critical insight on failure mechanisms and lifetimes of energy materials because they can provide non-destructive measurements of structure, chemistry, and composition of batteries while they are running (in operando) or over time. Because of this, synchrotron approaches have been critical to the development of improvements to existing lithium ion batteries and for creating novel energy schemes such as lithium-sulfur and lithium-air batteries.

Sigray’s portfolio of x-ray systems enable some of the most cutting-edge research in novel battery formulations and materials, including changes to the chemistry, composition, and structure of batteries as a function of cycling.

Read our comprehensive technical note on the advantages of the approaches in our technical white paper in the link below.

Battery Bond Lengths as a Function of Cycling

XAS has become a gold standard approach for characterizing structural and electronic information of electrodes, thereby providing an understanding of electrochemical mechanisms governing a given battery’s chemistry. Sigray’s QuantumLeap enables both ex-situ determination of electrocatalyst chemistry and the use of in-situ cells to study chemical changes in-operando.

Sigray’s applications note (linked below) describes evaluating the Mn, Co, and Ni bonds of a NMC LIB, finding the Ni-O suffers from Jahn-Teller distortion whereas the local environment is preserved.

FT-EXAFS of Ni in NMC, showing the comparison of the charged and discharged state of the NMC electrodes along with the model systems
Speciation of Co in NMC Batteries

Sigray’s applications note (linked below) demonstrate the synchrotron-like quality of Sigray’s data to enable Co speciation of an NMC LIB, finding three isobetic points of Co XANES. PCA and ITTFA reconstruction of the XANES show that two unique species of Co are seen in four NMC samples.

PCA analysis of Co species in NMC batteries
Battery Chemistry through XAS

Customers around the world are using the QuantumLeap for development of novel battery materials. Several of the groups are now publishing with high quality (K=12 or greater) XANES data. One example is a group at Shanghai Jiao Tong University (SJTU), who reported advances in the promising Ni-Zn batteries by carbon dot coating of the ZnO anode materials to extend material lifetime.

XANES of a new and cycled battery
In Operando Pouch Cell Batteries

Pouch cell batteries are one of the most challenging samples to image at submicron resolution. They are simply too large for even the leading microCTs and XRMs to image at suitable acquisition rates at the high resolutions (0.5 µm) needed for quantifying microstructural changes.

3D Battery Structural Defects

3D X-ray Microscopy has become a gold standard for investigating battery failures and the structural defects that cause them. Shown to the right are various failures investigated with Sigray’s EclipseXRM in intact batteries. More information and figures can be seen in the article below, published on Cell Reports and using EclipseXRM (previous generation was named PrismaXRM) for the x-ray microscopy images and AttoMap for the microXRF data.

Battery defects [Qian et al, Cell Reports 2021]
Ultrahigh resolution imaging of battery cathodes using EclipseXRM (0.21 um voxel)
In Operando Growth of Dendrites

The formation of Zn dendrites jeopardize the cell cycle life in novel Zn-ion battery schemes. Sigray’s EclipseXRM provided the resolution and speed to see the in-situ growth of dendrites.

Dendritic growth in Zn-ion battery, imaged on EclipseXRM (note previous generation system was named PrismaXRM)
3D Microstructural Evolution of Electrodes

The microstructure of electrodes are increasingly of interest because it is now recognized that damage incurred and agglomeration of particles from charging limits the long-term reliability and lifetime. TriLambdaXRM provides the resolution needed to see these changes – and because of the non-destructive nature of x-rays, can be used to observe such changes over time or in-operando.

3D Imaging of Intact Batteries and Batteries in-operando

Sigray’s EclipseXRM provides submicron high resolution even for large samples and samples placed within in situ cells. The flexibility of the EclipseXRM in switching between multiple fields of view allows hierarchical characterization of batteries – from the full FOV to detailed region-of-interest imaging – without requiring de-packaging the battery. This allows non-destructive identification of problems such as small defects (cracks, particles) and shorts.

Read the paper published at Journal of Materials Chemistry A.

Hierarchical imaging of battery with Sigray PrismaXRM. Publication by GB Zan. Sample courtesy of J Zhang, F Monaco, G Qian, J Li, P Cloetens, P Pianetta, and Y Liu.
Transition-metal Precipitation Mapping

High-nickel LiNixMnyCo1-x-yO2 (NMC) cathodes have emerged as a highly promising cathode candidate for next-generation lithium-ion batteries (LIBs). Battery cell operation with a high cutoff voltage is another broadly adopted approach to increase energy and power density. Unfortunately, the high-voltage cycling approach exacerbates the degradation of the NMC cathode, including the surface lattice reconstruction and transition metal dissolution. Sigray’s AttoMap microXRF uncovers the diffused precipitation of Mn, Co, and Ni, as well as their spatial distributions on the lithium metal anode.

Read Paper in Materials Today
Sigray AttoMap used to measure diffused precipitation of Mn, Co, and Ni, as well as their spatial distributions on the lithium metal anode.
Sigray AttoMap used to measure diffused precipitation of Mn, Co, and Ni, as well as their spatial distributions on the lithium metal anode.
Contamination in Battery Manufacturing and Metal Migration

Thermal runaway is one of the primary concerns in lithium ion batteries (LIBs) that is often caused by an internal short circuit. Such shorts can occur because of contaminants such as iron particles introduced during the manufacturing process. Sigray’s AttoMap microXRF provides high sensitivity at rapid speeds (down to 2ms/point) to quickly screen for contaminants.

For R&D researchers, the AttoMap’s high spatial resolution and sensitivity enable imaging of trace-level metal migration in electrodes between battery cycling. The system complements XRD and XAS systems by providing the distribution of elements of interest at microns-scale resolution.

Iron contaminants found in a large electrode surface. These contaminants were then segmented and quantified (size and number).
Impurities measured with Sigray AttoMap. Published in Cell Reports.