X-ray nano-CT Research Articles

Influence of previous drought exposure on the 3D microstructure of the cambium and developing xylem in Eucalyptus clones: An X-ray CT investigation

Summary In plant biology research, X-ray computed tomography (CT) has been demonstrated to be useful for studying the complex tissues of trees qualitatively and quantitatively. The cambium plays a very important role in plant growth and development. However, this tissue is relatively poorly studied due to its complex nature and its localization between layers of xylem and phloem cells. Antecedent environmental conditions may have a substantial impact on plant responses to drought and recovery dynamics. Therefore, this study aimed to investigate the impact of previous drought exposure on the 3D microstructure of two commercial Eucalyptus clones by monitoring the development of the cambium, in the same plant and same area of cambial tissue, during a 4-week trial consisting of well-watered, mild drought, severe drought, and rewatering phases. To track microstructural changes, the plants were imaged weekly with non-destructive X-ray micro-computed tomography (μCT). On the last day of the experiment, X-ray nano-CT was also performed. Our results indicate that trees subjected to earlier well-watered conditions were more affected by the severe drought, compared to those previously exposed to mild drought conditions. Thus, previous exposure to water deficit may provide the benefit of increased drought tolerance during future water deficit. Previous mild drought exposure can facilitate morphological adjustments, which potentially enhances drought tolerance during subsequent drought events.

Impact mechanism of microscopic pore structure on sensitivity and ability of CO2-ECBM based on X-ray nano-CT

To scientifically explain the mechanism of increasing CBM production by CO2 injection pressure from the microscopic scale, and effectively evaluate the CBM production enhancement potential, adopting the fluid intrusion method and ray non-destructive testing technique, this research reconstructed the real coal microscopic pore structure and carried out the microscopic scale numerical simulation of CO2-ECBM. The results indicate that there exists a limit to the magnitude of growth in CO2-ECBM displacement efficiency driven by gas injection pressure. The pressure sensitivity, enhancing potential, and production enhancement ability of CO2-ECBM change continually over time. In high metamorphic coal reservoirs, the disadvantages of the engineering cycle, absolute displacement efficiency, and CBM production-increasing ability are obvious, while pressure sensitivity and enhancing potential are higher in the middle and late stages. The differences exhibited by CO2-ECBM in different metamorphic coals are attributed to the pore structure quality. Specifically, high-quality pores have the characteristics of convenient passage, multiple paths, and higher pore surface areas. The findings can enrich the CO2-ECBM production enhancement mechanism in different coal seams, providing new theoretical viewpoints for accurately assessing its application effect and production enhancement potential.

Correlative Microscopy Analysis for Battery Materials

Lithium batteries (LB) are in high demand for a diverse range of applications, such as automotive industry, consumer electronics, wearable and medical devices, grid storage, etc. Each application demands a specific set of performance advantages, such as high capacity and/or energy density, long cycle life, superior electrochemical stability. Therefore, there is no one-size-fits-all for a LB chemistry and its form factor. Battery performance advantages rely on optimization of the battery components, including active materials, electrolyte, separator, binder system, and current collectors. For meaningful device optimization, electrochemical battery testing needs to be combined with a deep understanding of the material and device microstructure. Physical and chemical characterization on the material- and electrode-level is needed to establish root-cause relationships with battery performance. Properties of the interfaces between layers of the battery components often define the device characteristics. Critical information is usually buried beneath the surface of a material specimen or encapsulated in a closed-form device. Microstructural defect identification in the battery needs to be followed by a targeted defect study. Different battery form factors and chemistries make it hard to streamline root-cause analysis.Recently, a commercial focused-ion beam scanning electron microscope was developed with an integrated fs-laser mill attached to the load lock of the microscope, opening the door to new and more powerful analysis approaches in energy materials research. Applications include rapid access to deeply buried structures for high resolution imaging and analytics, large area cross-section preparation, and massive material ablation for sample preparation of structures; e.g. FIB-SEM tomography, TEM, APT, or X-ray nanoCT. Additionally, each of these methods may be correlatively guided by prior imaging, with techniques like 3D X-ray microscopy (XRM), to enable targeted analysis and preparation. The non-destructive nature of 3D XRM makes it an ideal tool for microstructural defect identification in LB. Laser mill allows researchers to combine non-destructive X-ray defect identification with electron microscopy methods for targeted defect characterization. This approach can be used for various battery types and form factors.By combining the laser mill with 3D X-ray microscopy, this platform enables comprehensive analysis of energy materials at the nanoscale. We illustrate these concepts with application examples, and use cases demonstrating the utility of the approach.

3D Operando Monitoring of lithiation spatial composition in NMC-cathode electrode by X-ray nano-CT & XANES-techniques

3D Operando Monitoring of lithiation spatial composition in NMC-cathode electrode by X-ray nano-CT & XANES-techniques

Advanced imaging and quantification of the cambium and developing xylem in eucalypts using X-ray micro- and nano-computed tomography

Summary In recent years, the popularity of X-ray computed tomography (CT), as a non-destructive imaging technique, has continued to expand in various research domains. In wood research, X-ray CT has proven to be useful for three-dimensional (3D) structural studies investigating the complex tissues of trees. Wood formation (i.e., xylogenesis) initiates in the cambium and a narrow zone of subsequent differentiation, both of which play key roles in plant growth and development. However, the dynamics of xylogenesis in eucalypts remain relatively poorly understood, in large part due to challenges in sampling, imaging, and characterizing the cambium. Therefore, the aim of this study was to present a workflow to evaluate the feasibility of using X-ray CT to characterize and quantify the structural properties of the cambium in eucalypts. The growth responses of Corymbia hybrid seedlings, exposed to either irrigated or droughted conditions, was investigated by monitoring the structural development of the cambium. To track microstructural changes in the cambium, the same seedlings were imaged with X-ray micro-CT (μCT) one day before the treatments and again six days after the respective treatments. After the last X-ray μCT scan, X-ray nano-CT was also applied. Using image analysis techniques, the morphological characteristics of the cambium could be determined. X-ray μCT displayed a larger, thicker cambial zone in irrigated plants, while a much thinner cambium was visible in droughted seedlings. X-ray nano-CT revealed that droughted plants were associated with a significantly () smaller cambium volume containing smaller cells, compared to the cambium of irrigated plants. Light microscopy was used to validate the CT results and demonstrated no significant () difference in the cambium width and cell diameter obtained from the two respective CT techniques. The findings of this study proved X-ray CT to be a valuable tool for examining the effect of changing environmental conditions on the complex cambium structure of Corymbia hybrid seedlings.

High Resolution Observation of Liquid Water in Polymer Electrolyte Fuel Cell Using X-Ray Nano Computed Tomography

Polymer electrolyte fuel cells (PEFCs) are attracting attention as energy device of low environmental impact because of their high generation efficiency and their emitting only water. The gas supplied to the PEFC is humidified, and water is produced at the cathode catalytic layer by the electrochemical reaction between oxygen and protons. The gas diffusion layer (GDL) and micro porous layer (MPL) in PEFC plays an important role in the transport of oxygen and water. When liquid water accumulates in the GDL, the supply of oxygen to the cathode is inhibited, resulting in poor generation performance. In order to maintain the performance of PEFCs, it is important to manage the water in the cell.Attempts have been made to visualize the liquid water in GDLs and MPLs for better GDL and MPL design; X-ray micro computed tomography (micro-CT) is one powerful tool for this. Visualization of liquid water in GDLs and MPLs using micro-CT has so far revealed the behavior of the produced water[1,2]. However, in previous studies, it has been difficult to visualize liquid water in the catalyst layer, which is the reaction field where the water is produced. This is because the spatial resolution of micro-CT is larger than a µm, which is insufficient for analyzing liquid water in the catalytic layer. X-ray CT measurements with a resolution of at least 150 nm are needed to measure the distribution of liquid water in the cross section of the catalyst layer. In this study, a measurement system to reveal the distribution of liquid water in the catalyst layer was developed using a 150 nm-spatial-resolution X-ray CT with a synchrotron radiation x-ray microscope called X-ray nano-CT.A GDL specimen prepared cut to a disk shape with 1 mm diameter. The GDL specimen mounted on a copper stage with high thermal conductivity connected Peltier element module. The micro-CT and nano-CT measurements were carried out in BL20XU beamline at SPring-8, Japan. An X-ray beam energy was 30 keV with a double crystal monochromator. The nano-CT measurements were performed using Zernike phase contrast with voxel size of 38.4 nm. We measured the micro-CT and nano-CT of the dry condition of the GDL specimen. Then, the GDL specimen injected liquid water was scanned. Injection of liquid water into the GDL specimen is not easy because of water-repellent of GDLs. Helium gas saturated water vapor at 40 °C was sprayed to the GDL at 30 ml/min, then the GDL cooled to 10 °C using a Peltier element module and the vapor was condensed inside of the GDL. The measurement setup is shown in Figure 1. This water injection in GDL method was based on the method reported by Kato et al [2].Figure 2 shows the optical system of the nano-CT used in this study. The optical system of this nano-CT provides a condenser zone plate for sample illumination, a Fresnel zone plate for enlarged image, and phase ring for Zernike phase contrast. These optics allow CT with a high spatial resolution of 150 nm to be measured even for materials with low X-ray absorption.A three-dimensional structure of GDL was revealed by CT measurements in each scale order. The distribution of liquid water in GDL were visualized with nanoscale spatial resolution (Figure 3). We have successfully visualized the three-dimension distribution of liquid water in the GDL with nm order scale using nano-CT. The newly established nano-CT with a spatial resolution of 150 nm order is extremely useful for elucidating liquid-water behavior in PEFCs containing catalyst layers, which was not clear before. Acknowledgements This work is based on results obtained from a NEDO FC-Platform project commissioned by the New Energy and Industrial Technology Development Organization (NEDO). This study was partially supported by the Synchrotron radiation experiments performed at BL20XU of SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal numbers 2021A2009, 2021B1015).

Observation of water droplets in microporous layers for polymer electrolyte fuel cells by X-ray computed nano-tomography.

An X-ray computed nano-tomography (nano-CT) system has been established at the BL33XU beamline of SPring-8. The optical system consists of pseudo-Köhler illumination with a sector condenser zone plate, an apodization Fresnel zone plate as the objective lens, and a Zernike phase plate. The imaging detector is a fiber-coupling type X-ray camera. The performance of the X-ray nano-CT system was confirmed by imaging an X-ray test chart. The system was subsequently applied to the observation of a microporous layer for polymer electrolyte fuel cells and a simulated microporous layer including liquid water. The nano-CT system, which can perform a computed tomography measurement in less than 4 min, allowed visualization of a spherical water droplet produced in the microporous layer. In the present study, the shape of water droplets in a nanoscale porous structure is investigated.

Insights into in-situ catalytic degradation of plastic wastes over zeolite-based catalyst from perspective of three-dimensional pore structure evolution

Insightfully understanding the process of volatiles from plastic depolymerization entering from the exterior into internal structure of catalyst favors to rationalize the catalyst design in scale-up principles. Herein, catalytic degradation of plastic wastes with fluid catalytic cracking catalyst (FCC) was investigated in-depth. The yield and composition of liquid and gas products over various FCCs were studied quantitatively. The structural evolution of catalyst on overall scope, including the topology of heterogeneous pore systems and spatial distribution of zeolite was probed by X-ray nano-CT. The results showed that FCC enhanced the transformation of C16-C30 chains to C9-centered monocyclic aromatics. The nano-CT analysis of FCCs illustrated remarkable loss of exterior porosity after reaction, particularly at the depth of ∼16.5μ m from the outmost layer. While the interior pores were marginally affected, indicating large hydrocarbons incapable of engaging with active sites to full advantage, which preferably occupied large-size pores (>385 nm) of external surface.

3D Operando Monitoring of Lithiation Spatial Composition in NMC Cathode Electrode by X-ray Nano-CT & XANES Techniques

3D Operando Monitoring of Lithiation Spatial Composition in NMC Cathode Electrode by X-ray Nano-CT & XANES Techniques

Application of X-ray nano-CT fluoroscopy and fluorescence spectroscopy in the study of ancient bronzes

Application of X-ray nano-CT fluoroscopy and fluorescence spectroscopy in the study of ancient bronzes

In-situ Tensile and Fatigue Testing for Detection of Interfacial Debonding between Carbon Fibers and Epoxy Matrix by Synchrotron Radiation X-ray Nano-CT

In-situ Tensile and Fatigue Testing for Detection of Interfacial Debonding between Carbon Fibers and Epoxy Matrix by Synchrotron Radiation X-ray Nano-CT

Three-dimensional structural measurement and material identification of an all-solid-state lithium-ion battery by X-Ray nanotomography and deep learning

Three-dimensional measuring method of the material distribution of an all-solid-state lithium-ion battery (ASSLiB) cathode, by synchrotron radiation high-resolution X-ray computational tomography (nanotomography, nano-CT) and deep learning is proposed in this study. The cathode of the ASSLiB comprised materials with high X-ray absorption coefficients, such as LiCoO 2 and LiNi 0.5 Co 0.2 Mn 0.3 O 2 . Such high absorption coefficients imparted difficulties in obtaining a high-resolution, high-contrast image and in identifying materials with conventional CT value method. The method proposed in this study was effective in acquiring a high-resolution image with fewer artifacts and measured the heavy materials at a high signal-to-noise ratio. We used deep learning with a customized U-net, enabling high accuracy and ultra-high-speed material identification. Using this method, constituent materials were successfully identified in three dimensions. This material identification technique showed great potential for application to other techniques such as focused ion beam–scanning electron microscopy. • High resolution imaging of ASSLiB is conducted with synchrotron radiation X-ray nano-CT. • Material identification technique for a CT image of ASSLiB by deep learning (U-net) is proposed. • The U-net segmented CT images at low computational cost and ultra-high speed • The segmentation approach can also be applied to other observation techniques

High-energy x-ray nanotomography introducing an apodization Fresnel zone plate objective lens.

In this study, high-energy x-ray nanotomography (nano-computed tomography, nano-CT) based on full-field x-ray microscopy was developed. Fine two-dimensional and three-dimensional (3D) structures with linewidths of 75 nm-100nm were successfully resolved in the x-ray energy range of 15 keV-37.7 keV. The effective field of view was ∼60 µm, and the typical measurement time for one tomographic scan was 30 min-60min. The optical system was established at the 250-m-long beamline 20XU of SPring-8 to realize greater than 100× magnification images. An apodization Fresnel zone plate (A-FZP), specifically developed for high-energy x-ray imaging, was used as the objective lens. The design of the A-FZP for high-energy imaging is discussed, and its diffraction efficiency distribution is evaluated. The spatial resolutions of this system at energies of 15 keV, 20 keV, 30 keV, and 37.7 keV were examined using a test object, and the measured values are shown to be in good agreement with theoretical values. High-energy x-ray nano-CT in combination with x-ray micro-CT is applied for 3D multiscale imaging. The entire bodies of bulky samples, ∼1mm in diameter, were measured with the micro-CT, and the nano-CT was used for nondestructive observation of regions of interest. Examples of multiscale CT measurements involving carbon steel, mouse bones, and a meteorite are discussed.

Microstructural evolution of electrodes in sintering of multi-layer ceramic capacitors (MLCC) observed by synchrotron X-ray nano-CT

Synchrotron X-ray nano computed tomography was used to investigate the microstructural evolution during co-sintering of multi-layer ceramic capacitors (MLCC) consisting of Ni electrodes and BaTiO3 dielectric layers stacked alternately. As the electrode thickness reduced to submicron at the scale of a few particle diameters, the process produced the defect of inner electrode leading to capacitance loss. The discontinuous electrode region contained round holes and irregularly-shaped channels. The formation of discontinuity was associated with the increase of characteristic length of heterogeneous electrode structure, i.e., the coarsening occurred. The evolution of electrode morphology by surface/interface diffusion caused the breakup of ligament between two holes driven by instability induced by surface tension and stress. The ligament pinch-off inevitably generated sharp points which might enhance the local electric field bringing about the dielectric breakdown. A model was presented to explain the formation of defect from the heterogeneous particles packing in the electrode layer.

Image alignment for synchrotron radiation based X-ray nano-CT

Synchrotron radiation-based X-ray nano-imaging is a powerful tool for non-destructively studying the internal nano-scale structure of matter. Here in this paper, we review the state-of-the-art image alignment technology in the field of nano-resolution imaging, and classify and analyze the technology according to the research stage. First, through the publications of image alignment algorithm, the development direction of future research is analyzed. Then, the most effective image alignment application in the field of nano imaging based on classic image alignment algorithms is summarized. The paper also presents the feature detection operators that are useful for nano-scale image registration selected from recent feature detection research, which has important guiding significance for the specific application and optimization of nano-imaging image registration. Finally, the state-of-the-art image registration method based on deep learning is introduced, the applicability and potential of deep learning in nano-imaging registration technology are discussed, and future research directions and challenges are prospected based on different neural network characteristics.

(Invited) Details Matter: Applying Computed Tomography and X-Ray Imaging to Advancing PEFCs

Polymer electrolyte fuel cells (PEFCs) continue to reach new levels of performance and are increasingly being used in passenger vehicles, heavy-duty vehicles, and stationary power supplies. In concert with these advancements, the tools used to identify new opportunities to further advance power density and durability as well as reduce costs must increasingly scrutinize finer details. Such details include the role of heterogeneities in bulk layers, unintentional or intentional gradients in material properties stemming from the manufacturing and film casting processes, the impact of interfacial zones, spatial distributions of the current generation and material degradation, as well as the impact of the three-dimensional (3D) micro/nanostructure. This talk will share recent advances in the application of micro-scale and nano-scale computed tomography (CT), including X-ray and electron CT, and will outline the state-of-art capabilities. Advanced methodologies that will be introduced include <50 nm resolution X-ray nano-CT and plasma focused ion beam-scanning electron microscopy (pFIB-SEM) for high-throughput, large field of view 3D imaging at <5 nm resolution. The talk will highlight recent advances in multi-modal/multi-scale imaging, CT-informed and image-based modeling, and operando X-ray imaging. Some examples include multi-modal X-ray CT imaging of catalyst layers to understand how ink properties and casting affects the structure, including the reorganization of ionomer during casting and drying. Regarding degradation analysis, the use of nano-CT for imaging the 3D redistribution of Pt in MEAs and pore structure evolution with accelerated stress tests will be highlighted. The talk will emphasize the various levels of using CT data to inform simulations, including recent applications of high-performance computing and open-source software to model coupled transport-reaction in large image domains resolving both the true pore and ionomer 3D distributions as well as the use of electron tomography images to simulate nm-scale gas and ion transport in single Pt/C aggregates. Finally, there will be a discussion of emerging operando X-ray imaging methods at sub-micrometer resolution for understanding the temporal evolution of materials, including catalyst layers and membranes.

Microstructural Evolution of Electrodes in Sintering of Multi-Layer Ceramic Capacitors (MlCC) Observed by Synchrotron X-Ray Nano-Ct

Synchrotron X-ray nano computed tomography was used to investigate the microstructural evolution during co-sintering of multi-layer ceramic capacitors (MLCC) consisting of Ni electrodes and BaTiO3 dielectric layers stacked alternately. As the electrode thickness reduced to submicron at the scale of a few particle diameters, the process produced the defect of inner electrode leading to capacitance loss. The discontinuous electrode region contained round holes and irregularly-shaped channels. The formation of discontinuity was associated with the increase of characteristic length of heterogeneous electrode structure, i.e. the coarsening occurred. The evolution of electrode morphology by surface/interface diffusion caused the breakup of ligament between two holes driven by instability induced by surface tension and stress. The ligament pinch-off inevitably generated sharp points which might enhance the local electric field bringing about the dielectric breakdown. A model was presented to explain the formation of defect from the heterogeneous particles packing in the electrode layer.

Methodology development and application of X-ray imaging beamline at SSRF

This paper introduces some latest developments regarding the X-ray imaging methodology and applications of the X-ray imaging and biomedical application beamline (BL13W1) at Shanghai Synchrotron Radiation Facility in the past 5 years. The photon energy range of the beamline is 8–72.5 keV. Several sets of X-ray imaging detectors with different pixel sizes (0.19–24 μm) are used to realize X-ray microcomputed tomography (X-ray micro-CT) and X-ray in-line phase-contrast imaging. To satisfy the requirements of user experiments, new X-ray imaging methods and image processing techniques are developed. In vivo dynamic micro-CT experiments with living insects are performed in 0.5 s (sampling rate of 2 Hz, 2 tomograms/s) with a monochromatic beam from a wiggler source and in 40 ms (sampling rate of 25 Hz, 25 tomograms/s) with a white beam from a bending magnet source. A new X-ray imaging method known as move contrast X-ray imaging is proposed, with which blood flow and moving tissues in raw images can be distinguished according to their moving frequencies in the time domain. Furthermore, X-ray speckle-tracking imaging with twice exposures to eliminate the edge enhancement effect is developed. A high-precision quantification method is realized to measure complex three-dimensional blood vessels obtained via X-ray micro-CT. X-ray imaging methods such as three-dimensional X-ray diffraction microscopy, small-angle X-ray scattering CT, and X-ray fluorescence CT are developed, in which the X-ray micro-CT imaging method is combined with other contrast mechanisms such as diffraction, scattering, and fluorescence contrasts respectively. Moreover, an X-ray nano-CT experiment is performed with a 100 nm spatial resolution. Typical user experimental results from the fields of material science, biomedicine, paleontology, physics, chemistry, and environmental science obtained on the beamline are provided.

Tetralin and Decalin H-Donor Effect on Catalytic Upgrading of Heavy Oil Inductively Heated with Steel Balls

The Toe-to-Heel Air Injection (THAI) combined with catalytic upgrading process in situ (CAPRI) has demonstrated it can simultaneously extract and upgrade heavy oil in situ. This paper reports the investigation of augmenting temperature deficit and suppressing coke formation in the CAPRI section through the incorporation of induction heating and H-donor solvents. An induction-heated catalytic reactor was designed and developed, heated with steel balls in a mixed bed of NiMo/Al2O3 catalyst (66% v/v) to 425 °C temperature, 15 bar pressure and 0.75 h−1 LHSV (Liquid Hourly Space Velocity). The catalyst surface area, pore volume and pore size distribution were determined by using nitrogen adsorption–desorption, while the location of coke deposits within the microstructure of the pelleted spent catalyst was analyzed with X-ray nano-Computed Tomography (X-ray nano-CT). Findings showed that induction heating improved the catalyst performance, resulting in a 2.2° American Petroleum Institute (API) gravity increase of the upgraded oil over that achieved with the conventional heating method. The increment in API gravity and viscosity reduction in the upgraded oils with nitrogen gas only, N2 and H-donor solvents, and hydrogen gas environments can be summarized as follows: decalin &gt; H2 gas &gt;= tetralin &gt; N2 gas. Meanwhile, the improvement in naphtha fraction, middle distillate fractions and suppression of coke formation are as follows: decalin &gt; H2 gas &gt; tetralin &gt; N2 gas. The X-ray nano-CT of the spent catalyst revealed that the pellet suffers deactivation due to coke deposit at the external surface and pore-mouth blockage, signifying underutilization of the catalyst interior surface area.

(Invited) Ex-Situ Tracking of Microstructural Evolution in Solid Oxide Cell Electrodes with Ptychographic Nanotomography

The 3D morphology of solid oxide cell (SOC) electrode microstructure and its evolution has a strong impact on the SOC electrochemical performance during their lifetime. The morphology of the nickel network, in nickel – yttria-stabilized-zirconia (Ni-YSZ) hydrogen electrodes is particularly influenced by: their initial start-up reduction profile, high temperature annealing, high current density operation and exposure to oxidation-reduction cycles. Thus, the development of 3D microstructure characterisation techniques to quantify the 3D microstructure parameters has been an intense topic of research. What remains challenging, due to SOC operating conditions, is to track non-destructively the evolution of the same volume of electrode material with high 3D spatial resolution from before, after and during processes which alter initial SOC microstructures[1–3]. Here we summarise the advantage of X-ray ptychographic nanotomography to image Ni-YSZ electrodes before and after oxidation[4], reduction[5] and annealing[6] with voxel resolutions below 55 nm. Ptychography provides outstanding data quality containing quantitative electron density image contrast. The image quality extrapolates to phase segmentations which in turn provide 3D microstructure parameters of sufficient quality to track the details of e.g. phase fractions, interfacial areas and triple phase boundary density of the changing electrode. Further to this, the image quality enables the possibility to observe the details of structural change of individual particles and interfaces as the basis for gaining fundamental insights into the operating mechanisms. In particular we draw attention to the benefits of identifying isolated particles as models of closed systems that can provide empirical control points into physically based 3D models of electrode evolution. Examples of: redox induced YSZ backbone mechanical failure, resulting change in the Ni particle size distribution and interfacial areas (see Fig. 1a); as well as the effects of annealing on Ni and pore phase percolation on the activity of individual TPBs and the coarsening of isolated Ni particles will be summarised (see Fig. 1b). The importance of appropriate sample preparation will also be discussed. Figure 1: a) Magnified view of a region of Ni-YSZ electrode evolving from the pristine state via the oxidised state to the re-reduced state illustrating the effects volumetric expansion and contraction of Ni/NiO on the YSZ backbone. Reprinted from [4], with permission from Elsevier. b) A magnified view of the Ni network in a Ni-YSZ electrode illustrating the detachment of a Ni particle from a thinly necked region of the Ni network during annealing. Reprinted from [6], with permission from Elsevier. Kennouche D, Chen-Wiegart YK, Yakal-Kremski KJ, et al (2016) Observing the microstructural evolution of Ni-Yttria-stabilized zirconia solid oxide fuel cell anodes. Acta Mater 103:204–210. https://doi.org/10.1016/j.actamat.2015.09.055Shearing PR, Bradley RS, Gelb J, et al (2011) Using Synchrotron X-Ray Nano-CT to Characterize SOFC Electrode Microstructures in Three-Dimensions at Operating Temperature. Electrochem Solid-State Lett 14:B117. https://doi.org/10.1149/1.3615824Shearing PR, Bradley RS, Gelb J, et al (2012) Exploring microstructural changes associated with oxidation in Ni–YSZ SOFC electrodes using high resolution X-ray computed tomography. Solid State Ion 216:69–72. https://doi.org/10.1016/j.ssi.2011.10.015De Angelis S, Jørgensen PS, Esposito V, et al (2017) Ex-situ tracking solid oxide cell electrode microstructural evolution in a redox cycle by high resolution ptychographic nanotomography. J Power Sources 360:520–527. https://doi.org/10.1016/j.jpowsour.2017.06.035De Angelis S (2017) Tracking Solid Oxide Cell Microstructure Evolution by High Resolution 3D Nano-Tomography. PhD Thesis Department of Energy Conversion and Storage, Technical University of Denmark. http://orbit.dtu.dk/files/139977895/finalDef2.pdfDe Angelis S, Jørgensen PS, Tsai EHR, et al (2018) Three dimensional characterization of nickel coarsening in solid oxide cells via ex-situ ptychographic nano-tomography. J Power Sources 383:72–79. https://doi.org/10.1016/j.jpowsour.2018.02.031 Figure 1