X-Ray Diffraction in the Battery Industry: Seeing the Structure Behind the Charge
If modern batteries are the engines of the energy transition, X-ray diffraction (XRD) is one of the mechanics that keeps them running. From lithium-ion cells in smartphones to solid-state batteries in electric vehicles, the performance and safety of these systems depend on the crystal structures hidden inside their electrodes, powders and coatings.
XRD gives engineers and researchers a direct view of those atomic arrangements—revealing how the materials that store and shuttle ions actually behave as a battery charges, discharges, or ages.
Personally, I’ve worked with novel battery materials as part of the Materials Science and Engineering Department at NTU, Singapore, for 7 years, and in crystallography for over 15. I’ve published multiple papers on the subject (https://doi.org/10.1021/acsami.0c03423), (https://doi.org/10.1002/advs.201903109, (https://doi.org/10.1016/j.cej.2019.03.251), and I’ve tried to distill out some useful knowledge below, citing examples and links to useful learning content when appropriate.
The Crystalline Heart of a Battery
Every rechargeable battery is a dance of ions and electrons between two electrodes:
The cathode, often made of layered or spinel oxides such as LiCoO₂, NMC, or LFP.
The anode, commonly graphite, silicon, or lithium metal.
The electrolyte, liquid or solid, which carries ions between them.
Each of these components relies on precise atomic ordering. In the cathode, lithium ions sit between layers of transition-metal oxides; in graphite, they slip between carbon sheets. When the structure distorts, collapses, or transforms into an unwanted phase, capacity fades and safety risks rise.
That’s where X-ray diffraction comes in: it allows scientists to measure those structural changes directly.
How XRD Tracks Battery Behaviour
When a powdered electrode material is irradiated with X-rays, its lattice planes diffract the beam at characteristic angles according to Bragg’s law. The resulting diffraction pattern acts like a fingerprint for the structure.
By comparing patterns at different stages—fresh, charged, discharged, or cycled thousands of times—researchers can see:
Phase transformations: For example, LiCoO₂ gradually converts to CoO₂ as lithium ions leave the lattice during charging. XRD reveals that transition in real time.
Lattice strain and expansion: As ions insert or extract, the lattice parameters shift slightly. High-resolution XRD can track these changes down to fractions of an angstrom. This gives insight and understanding to capacity changes over time, or how charging rates affect degradation in the long run.
Crystallite size and defect evolution: Peak broadening indicates particle refinement or accumulated strain during cycling.
New phase formation: Unwanted products such as Li₂CO₃ or metal fluorides can appear after extended use or thermal abuse, visible as new, quantifiable diffraction peaks. Lithium dendrites, small crystals of lithium that grow under charging stress, can quickly pierce through electrodes, causing short circuiting and runaway fires.
Such measurements give engineers early warnings about degradation mechanisms and insights into how to design more durable electrodes.
In-Situ and Operando XRD
Traditional XRD involves removing a powder sample from the cell and analyzing it ex-situ. But today, laboratories use in-situ or operando XRD setups—where the diffraction experiment occurs while the battery is charging or discharging.
These systems use specially designed cells with X-ray-transparent windows, allowing scientists to watch structural changes unfold second-by-second. For example:
Lithium iron phosphate (LFP) shows a two-phase coexistence region during charge, where LiFePO₄ and FePO₄ peaks appear simultaneously. Tesla vehicles use this technology.
Nickel-rich layered oxides (for instance NMC811) reveal irreversible phase transitions near full charge, correlating with capacity loss. These are commonly used where high-energy density solutions are required, like drones and portable electronics.
Silicon anodes display amorphization—visible as a fading of crystalline peaks over cycles.
This direct, time-resolved data is crucial for optimizing charge rates, additives, and protective coatings.
Quality Control and Manufacturing
Beyond research, XRD plays an important role in industrial production. Battery manufacturers use it to verify the crystalline phases of incoming materials and finished electrodes:
Cathode production: Checking that calcination yields the correct layered or spinel structure, without impurity phases such as rock-salt.
Anode powders: Confirming graphite crystallinity and interlayer spacing.
Solid-state electrolytes: Ensuring complete reaction of precursors and monitoring unwanted amorphous regions.
Because XRD is non-destructive, it fits naturally into quality assurance workflows. A well-tuned diffractometer can process tens or even hundreds of samples a day, flagging deviations before they reach cell assembly lines.
Rietveld Refinement and Quantitative Analysis
Modern data analysis goes far beyond simple phase identification. Using Rietveld refinement, entire diffraction patterns are fitted to theoretical models, allowing extraction of:
Lattice parameters and volume (for state-of-charge tracking)
Atomic site occupancies (e.g. monitoring ion movements)
Microstrain and crystallite size
Relative phase fractions in multi-component blends
For example, in a mixture of LFP and FePO₄, the refined weight fractions correlate directly with the cell’s state of charge—providing a structural analogue to electrochemical data.
Quantitative XRD thus bridges the gap between chemistry and performance metrics.
XRD in Battery Recycling
As battery use soars, recycling becomes as critical as production. Discharged cells contain complex blends of oxides, metals, carbon, and electrolyte residues. X-ray diffraction is a cornerstone for characterizing black mass—the powder recovered after mechanical and chemical processing.
By comparing diffraction patterns before and after leaching or roasting, recyclers can:
Identify target phases such as LiCoO₂, Li₂CO₃, NiO, or spinel remnants.
Monitor phase purity after hydrometallurgical treatment.
Verify that lithium and transition metals have been successfully recovered into usable oxides.
This ensures consistent feedstock quality for closed-loop manufacturing and helps meet regulatory traceability requirements.
Where XRF Fits In
While XRD identifies crystal structures, X-ray fluorescence (XRF) complements it by revealing elemental composition. In recycling workflows, XRF quantifies how much nickel, cobalt, and manganese remain in each processing step.
Together, XRD and XRF provide a comprehensive fingerprint:
XRD shows how the atoms are arranged, and which phases are present
XRF shows which atoms are present and in what proportion.
Combined, they form a rapid, non-destructive toolkit for assessing both purity and structure in recycling and material qualification. Baskerville X-ray can provide and help you interpret both techniques.
Looking Ahead
Next-generation batteries—solid-state, sodium-ion, lithium-sulfur—push XRD to new frontiers. High-flux synchrotron sources now capture complete diffraction patterns in milliseconds, enabling real-time studies of nucleation, ion migration, and degradation. Meanwhile, compact benchtop diffractometers make these insights accessible to smaller R&D and manufacturing labs.
At Baskerville X-ray, we support both ends of this spectrum: advanced refinement and modelling for research clients, and practical, routine analysis for production and recycling. Whether you need to verify a cathode’s phase purity, track lattice changes under cycling, or confirm the crystalline content of recycled black mass, XRD remains the most direct way to see the structure that drives battery performance.
Next in the Series
We’ll look at how X-ray diffraction (XRD) and fluorescence (XRF) supports the pharmaceutical industry, including it’s current uses as quality control and novel structure determination, to growing use cases that help monitor biologics structures during formulation changes.
