How X-Ray Tomography is Revolutionizing Our Energy Future
Imagine if scientists could peer inside a working battery as it charges and discharges, watching how energy flows at the molecular level. Or observe exactly how solar cells degrade over time, atom by atom.
This isn't science fiction—it's the revolutionary power of high-dimensional and high-resolution X-ray tomography, a cutting-edge imaging technique that's transforming how we study and design the energy materials of tomorrow.
In our quest for better batteries, more efficient solar cells, and cleaner energy technologies, researchers have long faced a fundamental challenge: you can't improve what you can't see. Traditional microscopy methods often require slicing samples open or operating in artificial conditions that don't reflect how these materials function in the real world.
X-ray tomography shatters these limitations by allowing non-invasive, three-dimensional viewing of materials while they're actually working 9 .
This powerful technology is particularly crucial for energy materials, where dynamically evolving structural and chemical defects play a vital role in functionality 2 . As we push for more sustainable energy solutions, understanding these nanoscale transformations becomes essential—and X-ray tomography provides the window we need to watch these processes unfold in real time.
At its core, X-ray tomography works on principles similar to medical CT scans, but with extraordinary resolution that can reach down to nanometers—that's thousands of times smaller than a human hair 9 . The technique constructs three-dimensional images from two-dimensional X-ray projections taken at different orientations 8 .
What makes modern X-ray tomography truly revolutionary is its ability to go beyond simple structural imaging. High-dimensional spectrotomography adds chemical and electronic information to the mix, creating rich datasets that reveal not just what materials look like, but what they're made of and how they're behaving at the atomic level 2 .
Several specialized X-ray imaging techniques have emerged, each with unique strengths for different energy applications:
| Technique | How It Works | Best For | Resolution |
|---|---|---|---|
| TXM (Transmission X-ray Microscopy) | Similar to optical microscopy but uses X-rays, with an objective lens magnifying the image 9 | 3D morphology of battery electrodes and particles 9 | Tens of nanometers 9 |
| STXM (Scanning Transmission X-ray Microscopy) | Uses a focused X-ray beam to scan across samples, building images point by point 9 | Chemical state mapping and spectroscopy 9 | 12-40 nanometers 9 |
| X-ray Projection Imaging | Sample placed between X-ray source and detector without additional optics 9 | Studying larger structures and devices 9 | Several micrometers to tens of micrometers 9 |
| CDI (Coherent Diffraction Imaging) | Uses computational algorithms to form images from scattered light patterns without lenses 9 | Imaging crystal structure, strain, and lattice distortions 9 | Tens of nanometers 9 |
The secret weapon of modern X-ray tomography is synchrotron light sources—massive particle accelerators that generate incredibly bright, focused X-ray beams. These facilities, such as the Diamond Light Source in the UK, provide X-rays that are highly intense, monochromatic, and coherent, allowing researchers to penetrate dense materials while achieving exceptional signal-to-noise ratios 8 . This combination enables the non-destructive examination of internal features with extraordinary clarity.
One of the most impactful applications of X-ray tomography has been in understanding why lithium-ion batteries degrade over time. Despite their widespread use in everything from smartphones to electric vehicles, all batteries gradually lose their ability to hold a charge. For decades, the exact mechanisms behind this degradation remained hidden inside operating batteries.
A landmark experiment changed this by using high-resolution X-ray tomography to study lithium-ion battery electrodes under realistic operating conditions 2 . Researchers designed special test cells that could be placed in the X-ray beam while charging and discharging, allowing them to watch nanoscale changes as the batteries operated.
The methodology followed several careful steps:
Researchers prepared specially designed battery cells with transparent windows that allowed X-rays to pass through while maintaining normal battery function. Electrode materials were crafted to include various compositions of lithium-rich cathode materials known to suffer from voltage fade 2 .
The team placed these test cells in the path of a synchrotron X-ray beam and conducted operando experiments—meaning they collected data while the batteries were actively charging and discharging. This approach provided real-time information rather than just snapshots before and after cycling 9 .
Researchers combined several X-ray techniques simultaneously, including TXM for structural information and X-ray spectroscopy for chemical analysis. This allowed them to correlate physical changes with chemical transformations in the electrode materials 9 .
As X-rays passed through the sample from multiple angles, detectors recorded the transmitted intensity. Advanced computational algorithms then reconstructed these 2D projections into detailed 3D models of the battery's internal structure 1 .
| Observation | Scientific Significance | Practical Implications |
|---|---|---|
| Structural cracks forming in cathode particles during cycling | Revealed how mechanical stress contributes to performance decline | Suggests need for more flexible electrode materials that can withstand volume changes |
| Chemical heterogeneity in oxygen oxidation states | Identified root cause of voltage fade in lithium-rich cathodes | Provides target for designing more chemically stable materials |
| Non-uniform activity across electrode surface | Showed that some regions work harder than others, leading to faster local degradation | Indicates need for better electrode architecture to distribute workload evenly |
| Phase segregation during charging | Demonstrated how different crystal structures coexist, creating internal stress | Explains irreversible capacity loss in high-energy battery systems |
The results were revelatory. Scientists observed how tiny nanoscale cracks developed in electrode particles with each charge-discharge cycle, gradually reducing the material's ability to store and deliver energy 2 . Even more importantly, they tracked how the chemical state of oxygen evolved in real-time within the cathode materials, directly linking these changes to the gradual voltage fade that plagues advanced battery designs 2 .
Perhaps the most valuable insight came from watching how degradation occurred unevenly across electrode surfaces. Some regions showed intense activity and rapid deterioration, while others remained relatively unchanged—a phenomenon that would be impossible to detect without 3D, real-time imaging 2 .
Essential Equipment for Energy Material Imaging
While battery research has benefited tremendously from X-ray tomography, the applications extend far beyond energy storage. Scientists are now using these techniques to optimize fuel cells, improve solar panel materials, and develop advanced catalysts for clean energy production. In each case, the ability to watch materials function in real time at the nanoscale is accelerating the design cycle for next-generation technologies 9 .
The future of X-ray tomography lies in pushing toward even higher resolution, faster imaging speeds, and more sophisticated data analysis techniques. Emerging methods like coherent diffraction imaging (CDI) promise to eliminate the need for lenses entirely, instead using computational algorithms to reconstruct images from X-ray scattering patterns 9 . This approach could push resolution limits even further while reducing artifacts that can complicate image interpretation.
Understanding degradation mechanisms in lithium-ion and next-generation batteries.
Optimizing perovskite and silicon solar cells for higher efficiency and durability.
Improving catalyst distribution and membrane structure in hydrogen fuel cells.
Designing more efficient catalysts for clean energy production and storage.
As we stand at the threshold of a global energy transition, the role of advanced characterization techniques like X-ray tomography cannot be overstated. By allowing us to see and understand the intricate dance of atoms and electrons within energy materials, this technology provides the fundamental insights needed to design more efficient, durable, and affordable clean energy technologies.
The "invisibility" that once hampered energy research is rapidly fading, thanks to the penetrating power of X-rays and the clever scientists who harness them. As these techniques become more accessible and powerful, they'll continue to illuminate the path toward a sustainable energy future—one nanoscale discovery at a time.