The Use of Operando Imaging for Battery Analysis

By Ibtisam AbbasiReviewed by Lexie CornerJan 20 2025

Over the past two decades, there has been a significant shift toward sustainable and green energy systems, with batteries playing a central role in enabling seamless operations. Monitoring the electrochemical reactions occurring during battery operation is essential to ensure the collection of accurate data.

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Operando imaging has become an important tool for observing and understanding battery behavior, supporting continuous advancements in next-generation battery research and bridging the gap between theoretical concepts and practical applications.

What is Operando Imaging?

Operando imaging is a method used to study battery systems. It allows real-time observation of internal processes during operation.¹ This technique detects both macro-scale structural changes and sub-atomic electrochemical dynamics, offering higher precision than many conventional methods.

In-situ/operando imaging methods are compatible with modern electrochemical systems and provide high sampling rates, enabling the capture of rapid kinetics and physio-chemical changes at the atomic level. These non-destructive techniques do not require physical contact with the battery, reducing the risk of damage.²

Operando imaging has addressed the limitations of traditional kinetic analysis by enabling detailed observation of the full lifecycle of batteries, including cycling, charging, and discharging processes. Techniques such as spectroscopy, microscopy, and bulk-sensitive methods like X-ray diffraction are used to monitor electrochemical reactions and interfacial changes comprehensively.³

Key Operando Imaging Analysis Techniques

X-Ray Imaging

Several operando X-ray imaging techniques are used to study modern batteries. Full-field operando X-ray microscopy, for example, focuses a synchrotron X-ray beam to micrometer-scale resolution using a capillary condenser. This technique is particularly effective for observing dynamic electrochemical reactions, such as phase transitions in fuel cells and batteries.

Operando X-ray fluorescence microscopy is another valuable method, enabling sensitive elemental analysis to trace material distribution and structural variations. Additionally, operando X-ray nanotomography captures structural changes in electrodes, including volumetric and specific surface area variations during operation.⁴

Together, these operando X-ray imaging techniques provide detailed insights into lattice dynamics and material structural changes, offering high temporal and spatial resolution.

Electron Microscopy

Operando electron microscopy is used to study battery interface evolution, providing valuable information for optimizing battery performance. It is particularly effective for surface characterization, allowing direct visualization of electrodes and detailed analysis of localized morphology and structure at the nanoscale.⁵

In-situ/operando scanning electron microscopy (SEM) is commonly used to monitor structural changes in active materials during battery operation. This real-time observation helps in evaluating battery performance, identifying degradation mechanisms, and improving the design of electrode materials. These methods are also highly effective for studying interfacial reactions in rechargeable batteries, supporting efforts to enhance their performance and lifespan.⁶

Spectroscopic Methods

Operando spectroscopic methods are used to study molecular changes and interface variations in battery materials.⁷

Operando X-ray absorption spectroscopy (XAS) is a technique that analyzes the electronic structure of battery materials at the sub-atomic and molecular levels. Operando Raman spectroscopy is another powerful optical technique that provides time- and space-resolved data about electrode surfaces, enabling the detailed monitoring of changes caused by electrochemical reactions within battery cells.⁸

These techniques facilitate the tracking of electronic state changes at the nanoscale, contributing to the optimization of battery design and supporting the development of advanced rechargeable batteries.

Applications During Different Stages

Battery Charging

Changes at the electrodes during charging have a direct impact on battery performance. Operando imaging and analysis techniques are used to study these changes, ensuring safe operation and extending battery lifespan.

For example, operando imaging techniques have been used to study lithium-ion intercalation during charging. Researchers in Japan used operando X-ray diffraction at 0 °C and 25 °C to analyze the charging mechanisms of graphite electrodes in lithium-ion batteries.

At 25 °C, the intercalation of lithium ions produced a stage 1 compound with an in-plane structure of LiC₆. In contrast, at 0 °C, only stage 2 compounds were formed, featuring in-plane structures of LiC₉ and LiC₆. The expansion of graphite along the a-, b-, and c-axes was smaller at 0 °C compared to 25 °C, highlighting the temperature-dependent behavior of lithium-ion intercalation.

Operando imaging also provided insights into three key phases of the charging reaction: ion conduction in the electrolyte, lithium-ion transfer at the electrode-electrolyte interface, and lithium-ion intercalation into active material particles. Additionally, high-resolution observations revealed microstructural phase changes in graphite.⁹

Battery Cycling

Operando imaging techniques have been successfully used to study the evolution of the electronic structure of cathodes in modern batteries during cycling. These methods enable morphological analysis of cathode materials, allowing researchers to identify defects, observe crack propagation, and track changes in shape and size.¹⁰

Operando characterization techniques are among the most accurate tools for understanding degradation processes during battery cycling. For example, a German research team led by Natalia Canas employed operando X-ray diffraction (XRD) to analyze electrochemical and structural changes in batteries at normal and high operating temperatures.

Using an in-situ cell, the team observed that the first lithiation of graphite anodes resulted in an irreversible loss of capacity due to the formation of a solid-electrolyte interphase (SEI).

At higher temperatures, the researchers detected accelerated solvent molecule decomposition, leading to the formation of a thicker or less stable SEI, which negatively impacts cyclic stability and accelerates material degradation. The intercalation of lithium into graphite also caused an expansion of the interlayer spacing, a natural process during lithiation, but one that contributes to structural degradation over time.

Operando imaging further revealed a more disordered intercalation process at higher temperatures compared to room temperature. This irregularity promoted localized inhomogeneities, exacerbating material degradation.¹¹ These findings underscore the importance of monitoring battery cycling reactions using operando techniques to study material degradation and electrolyte breakdown, ultimately aiding in the development of strategies to extend battery lifespan.

Battery Discharge

During the discharging process, many high-energy-density batteries face challenges related to dendrite formation, which presents a key challenge in their commercialization. In the past, theoretical models were primarily used to study lithium and zinc (Zn) dendrite formation. In recent years, operando imaging techniques have enabled real-time analysis of dendrite growth, helping to reduce the risk of short circuits.¹

For example, Dai et al. used operando X-ray spectroscopy and imaging to analyze the morphological development of Zn dendrites. Understanding the origins of dendrite formation is essential for improving the stability of rechargeable batteries and preventing such occurrences in future systems.

In the early stages of dendrite formation, the hydrogen evolution reaction was found to accelerate Zn dissolution, promoting the growth of Zn dendrites with whisker and moss-like morphologies. Operando surface characterizations revealed that these morphologies primarily consist of ZSH and ZnO.

The researchers demonstrated that a dense, stable SEI film prevents dendrite formation and propagation. By introducing a 50 mM lithium chloride additive, they successfully inhibited dendrite growth, extending battery operational life to 3900 hours.¹² This level of detailed characterization, made possible through operando imaging, is vital for enhancing the safety and stability of next-generation battery systems.

Challenges and Future Considerations

Operando imaging and analysis techniques, while widely used, are complex processes that require specialized instruments with high resolution. These instruments are expensive, increasing the overall cost of the analysis.

Current operando electron microscopy setups have limited testing capabilities and are less effective for analyzing the long-term degradation of battery materials. There is a growing need to develop real-time operando techniques for studying battery behavior over extended operational cycles.

Researchers are also exploring operando cryo-electron microscopy (cryo-EM) to capture battery states during charging and discharging. However, cryo-EM requires precise sample preparation, and improving this aspect will be essential for producing high-quality specimens for operando analysis in the future.

Advancements in nanotechnology and data processing are expected to make operando imaging more efficient and compact. Developments such as higher-resolution cameras and improved infrastructure will enhance signal-to-noise ratios while minimizing specimen damage.

As these technologies evolve, operando imaging will play an increasingly significant role in understanding battery processes and advancing the development of efficient, high-performance batteries.

How do CT Instruments Help with Battery Analysis?

References and Further Reading

1. Foroozan, T., et al. (2020). Mechanistic understanding of Li dendrites growth by in-situ/operando imaging techniques. Journal of Power Sources. https://doi.org/10.1016/j.jpowsour.2020.228135
2. Li, H., et al. (2023). Recent Advances of In Situ and In Operando Optical Imaging Techniques for Battery Researches. Current Opinion in Electrochemistry. https://doi.org/10.1016/j.coelec.2023.101376
3. Nageswaran, G. (2020). Operando X-ray spectroscopic techniques: a focus on hydrogen and oxygen evolution reactions. Frontiers in chemistry. https://doi.org/10.3389/fchem.2020.00023
4. Wang, L., et al. (2018). Probing battery electrochemistry with in operando synchrotron X‐ray imaging techniques. Small Methods. https://doi.org/10.1002/smtd.201700293
5. Basak, S., et al. (2022). Characterizing battery materials and electrodes via in situ/operando transmission electron microscopy. Chemical Physics Reviews. https://doi.org/10.1063/5.0075430
6. Zhou, S., et al. (2023). Perspective of operando/in situ scanning electron microscope in rechargeable batteries. Current Opinion in Electrochemistry. https://doi.org/10.1016/j.coelec.2023.101374
7. Amaral, M., et al. (2023). In situ and operando infrared spectroscopy of battery systems: Progress and opportunities. Journal of Energy Chemistry. https://doi.org/10.1016/j.jechem.2023.02.036
8. Tian, J., et al. (2020). In situ/operando spectroscopic characterizations guide the compositional and structural design of lithium–sulfur batteries. Small Methods. https://doi.org/10.1002/smtd.201900467
9. Fujimoto, H., et al. (2021). Analysis of intercalation/de-intercalation of Li Ions Into/from graphite at 0° C via operando synchrotron X-ray diffraction. Journal of The Electrochemical Society. https://www.doi.org/10.1149/1945-7111/ac2280
10. Cho, BK., Jung, SY., Park, SJ., Hyun, JH., Yu, S. H. (2024). In situ/operando imaging techniques for next-generation battery analysis. ACS Energy Letters. https://doi.org/10.1021/acsenergylett.4c01098
11. Cañas, N., et al. (2017). Operando X-ray diffraction during battery cycling at elevated temperatures: A quantitative analysis of lithium-graphite intercalation compounds. Carbon. https://doi.org/10.1016/j.carbon.2017.02.002
12. Dai, H., et al. (2024). Unraveling chemical origins of dendrite formation in zinc-ion batteries via in situ/operando X-ray spectroscopy and imaging. Nat Commun. https://doi.org/10.1038/s41467-024-52651-5

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