Primary funding for the work was provided by the Electron Microscopy of Soft Matter Program from the Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The battery assembly portion of the project was supported by the BATT program from the Vehicle Technologies program, through the Office of Energy Efficiency and Renewable Energy under U.S. DOE Contract DE-AC02-05CH11231. Hard X-ray microtomography experiments were performed at the Advanced Light Source which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Katherine J. Harry was supported by a National Science Foundation Graduate Research Fellowship.

1. Electrolyte Preparation
<ol>
	<li>Synthesize a 240 kg/mol &#8211; 260 kg/mol poly(styrene) - block - poly(ethylene oxide) copolymer (SEO) using anionic polymerization.
	<ol>
		<li>Perform all additional sample preparation in an Argon glovebox where the water and oxygen levels are controlled and remain &#60;5 ppm.</li>
		<li>Dissolve 0.3 g of polymer in anhydrous N-methyl-2-pyrrolidone (NMP) with dry lithium bis(trifluoromethane)sulfonimide (LiTFSI) salt. Use a LiTFSI salt to SEO mass ratio of 0.275 and an NMP to SEO mass ratio of 13.13. 
		Note: This quantity of polymer will yield a membrane large enough to make approximately 20 samples.</li>
		<li>Cast all of the polymer and salt mixture prepared in the steps above onto an approximately 15 cm by 15 cm square piece of nickel foil using a doctor blade. Dry the resulting film at 60 &#176;C O/N.</li>
		<li>After drying, peel the film from the Nickel foil and allow to dry further under vacuum at 90 &#176;C.</li>
		<li>Wrap the resulting freestanding film in Nickel foil and store inside an air-tight box in the glovebox for later use.</li>
	</ol>
	</li>
</ol>
2. Lithium &#8211; Lithium Symmetric Cell Preparation
<ol>
	<li>Use a 7/16 in&#160;diameter, round metal punch to cut out two lithium metal electrodes from a roll of 99.9% pure, battery-grade lithium metal foil.</li>
	<li>Use a 1/2 in&#160;diameter metal punch to cut out a piece of polymer electrolyte film. 
	Note: The lithium metal is softer and easier to punch than the polymer electrolyte.</li>
	<li>Sandwich the polymer electrolyte film between the two lithium metal electrodes and press the nickel tabs onto the electrodes.</li>
	<li>Vacuum seal the sample in an air-tight pouch made of polypropylene and nylon lined aluminum. 
	Note: One of the lithium electrodes is easily swapped with a cathode if one wants to study a full battery.</li>
</ol>
3. Symmetric Cell Cycling
<ol>
	<li>Place the vacuum-sealed sample into an oven held at 90 &#176;C and cycle using electrochemical cycling equipment. Heat the sample during cycling to achieve reasonable ionic conductivity through the electrolyte membrane. For safety, ensure that the sample does not approach the lithium metal melting point of 180 &#176;C.</li>
	<li>Pass a current density of 0.175 mA/cm2 through the sample for 4 hr and follow with a 45 min&#160;rest. Next, pass a current density of -0.175 mA/cm2 through the sample for 4 hr and follow with a 45 min&#160;rest. Repeat this cycling routine as many times as desired.</li>
	<li>Observe the voltage response for this current density passed through a 30 &#181;m thick SEO electrolyte and compare with that shown in Figure 1. Stop the cycling routine when the cell voltage response drops to 0.00 V, because the battery has failed by short-circuit indicating the growth of lithium dendrites.</li>
</ol>
4. Synchrotron Hard X-ray Microtomography Imaging
<ol>
	<li>After the symmetric cell is cycled, bring it back into the glove box and remove it from its pouch.</li>
	<li>Use a 1/8 inch metal punch to cut out the center portion of the cell.Vacuum seal the center portion of the cell in pouch material and remove from the glovebox for transport to the synchrotron facility. 
	Note: By imaging a sample with a reduced diameter, the amount of material outside of the field of view of the X-ray detector is reduced. This improves the overall image quality by reducing noise caused by this extra material. Furthermore, removal of the highly X-ray absorptive Nickel current collectors is necessary, for this particular pouch design, to obtain clear X-ray images.</li>
	<li>Once at the beamline, use polyimide tape to affix the sample to the sample stage. If desired, tape a small metal marker on top of the sample to aid with alignment. Place the metal marker roughly in the center of the sample to mark the location around which the sample will rotate once aligned.</li>
	<li>Use 20 keV X-rays to image the sample with an exposure time optimized for the system. Optimize the exposure time by balancing the scan time and the number of counts per image. Estimate the total scan time by multiplying the exposure time by the number of images collected.
	<ol>
		<li>Here, use an exposure time of 300 msec, resulting in a scan time of 5 to 10 min.</li>
	</ol>
	</li>
	<li>Measure the pixel size associated with the optical lenses at the beginning of every beamtime shift. 
	Note: For the 4x lens used to take the image shown in Figure 2, the pixel size was 1.61 &#181;m/pixel. Higher magnification lenses (10x and 20x) are also available for use.</li>
	<li>Position and align the sample on a rotation stage with respect to the detection system so that it remains in the detector&#8217;s field of view as it rotates through 180&#176;.</li>
	<li>Position the sample as close to the detector as is possible while ensuring that the sample does not hit the detector at any rotation angle. 
	Note: As the sample to detector distance increases, the Fresnel phase contrast will become more pronounced in the reconstructed images. This can obscure features and result in poorer resolution. For pouch cells, the sample to detector distance is typically on the order of 3 cm away from the detector.</li>
	<li>Once aligned, perform a scan consisting of 1,025 images collected over sample rotations between 0 and 180&#176;. Collect &#8220;Bright field&#8221; (also known as &#8220;flat field&#8221; or &#8220;background&#8221;) images by moving the sample out of the field of view. Additionally, collect &#8220;dark field&#8221; images by taking images while the beam is off. Use these to normalize the sample images for inhomogeneous illumination, scintillator response, and CCD camera response.</li>
</ol>
5. Image Reconstruction
<ol>
	<li>Tomographically reconstruct the set of 1,025 radiographs into a stack of images where each image represents a slice in the volume using the following procedure.
	<ol>
		<li>First, normalize the images by subtracting the &#8220;dark field&#8221; images from both the radiograph images and the &#8220;bright field&#8221; images. Divide the resulting radiograph images divided by the resulting &#8220;bright field&#8221; images.</li>
		<li>Next, perform tomographic reconstruction, the process by which the series of projection angles is transformed into a 3D image, on the normalized radiograph images according to manufacturer&#8217;s protocol. 
		Note: The reconstruction software outputs a series of images, each representing a horizontal slice through the sample.When stacked, this set of reconstructed images form a three-dimensional X-ray absorption map of the sample.</li>
	</ol>
	</li>
	<li>Visualize the individual slices or the sample in three-dimensions to see what the sample looks like on the inside.</li>
</ol>
6. Data Visualization and Processing
<ol>
	<li>Use one of a multitude of commercial and open source image processing software packages available for data visualization and analysis.22, 23</li>
	<li>Upon opening the stack of reconstructed images with the desired software, create orthoslices to show the xy, xz, and yz perspectives of the reconstructed data.</li>
	<li>Pan through these images and search for features of interest, like the lithium dendrite shown in Figure 2.</li>
	<li>Next, use segmentation (digital labeling) and 3D rendering tools to render the feature of interest in three-dimensions.</li>
	<li>To digitally segment the image, create a label field and use thresholding tools to select regions of the sample corresponding to a material.</li>
	<li>To recreate an image like that shown in Figure 2B, label the dark pixels lithium and the bright pixels electrolyte. Label the lithium contained in the dendrite separately from the top and bottom lithium electrodes.
	<ol>
		<li>Render the dendritic lithium in orange and the polymer electrolyte in blue. Render the top and bottom lithium metal electrodes in gray and adjust the transparency value to reveal the orange dendritic lithium. Rotate this three-dimensional reconstruction to view the structure from many perspectives.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

Hard X-ray microtomography is especially well-suited for air-sensitive samples, like many electrochemically active materials, since the X-rays can penetrate through protective pouch material, enabling facile imaging of the sample without exposure to air. Perhaps the most valuable characteristic of this imaging technique is that the penetrating X-rays allow the user to see inside of the sample without destroying it. Most common imaging techniques, like scanning electron microscopy and traditional optical microscopy, can o...

Researchers are actively investigating battery chemistries with theoretical energy densities over an order of magnitude larger than traditional lithium-ion batteries.1,2 These high-energy-density batteries will make electric vehicles more competitive with their gasoline-powered counterparts.3 However, these new chemistries have several failure modes that preclude their use in commercial technologies. For example, these battery chemistries require a lithium metal anode to achieve large enhancements in energy density; unfortunately, lithium metal is prone to dendrite growth as lithium ions are reduced at the anode surface during charging.4-9 Additionally, breakage of active particles in the cathode and poor adhesion within the battery can cause cell failure.10
Many modes of battery failure occur on the micrometer scale. However, most battery materials are air sensitive making sample preparation for analysis by electron microscopy and traditional optical microscopy difficult. Synchrotron hard X-ray microtomography allows one to visualize the interior of a battery without disassembly.11-14 Furthermore, the technique produces a three-dimensional (3D) reconstruction of the assembled cell making it easy to find locations of failure.15 Finding robust techniques that enable researchers to develop the scientific understanding required to accurately predict the lifetime of a battery is critical for the design of next generation battery technologies. The procedure discussed herein will specifically demonstrate how one can prepare and image model batteries to study the growth of lithium metal dendrites through solid polymer electrolyte membranes.
Computed tomography (CT) scanning is not a new technique and has been used frequently for failure analysis in industry. Synchrotron-based X-ray microtomography is advantageous because the high brightness and flux of the source allow collection of images with high resolution and good signal to noise in a much shorter amount of time.16 Additionally, one can take advantage of the X-ray energy resolution to image at energies around a chemical species&#8217; absorption edge, causing the components containing that chemical species to be identified.17 It was found that the synchrotron source provides sufficient flux to achieve good contrast between lithium metal and solid polymer electrolyte membranes enabling one to image lithium metal dendrites.15
The study discussed herein uses a high modulus, block copolymer electrolyte membrane.18 These high modulus membranes suppress lithium dendrite growth, lengthening the lifetime of batteries.19,20 However, dendrites still eventually puncture the membrane causing the battery to fail by short-circuit. It is important to understand the nature of dendrite formation and growth in these high modulus electrolyte membranes in order to design strategies to prevent their growth.

<table><tbody><tr><td>Anhydrous N-methyl-2-pyrrolidone&amp;nbsp;</td><td>MILLIPORE</td><td>MX1396-7</td><td></td></tr><tr><td>Lithium bis(trifluoromethane)sulfonamide</td><td>MILLIPORE</td><td>8438730010</td><td></td></tr><tr><td>Lithium metal</td><td>FMC Lithium</td><td>None</td><td>Lectro Max 100</td></tr><tr><td>Pouch material</td><td>MTI Corporation</td><td>EQ-alf-400-7.5M</td><td></td></tr><tr><td>Nickel tabs</td><td>MTI Corporation</td><td>EQ-PLiB-NTA3</td><td></td></tr></tbody></table>

failure analysis of batteries using synchrotron-based hard x-ray microtomography

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent of lithium-ion batteries, researchers have known that the lithium metal anode has the highest theoretical energy density of any anode material. However, rechargeable batteries containing a lithium metal anode are not widely used in consumer products because the growth of lithium dendrites from the anode upon charging of the battery causes premature cell failure by short circuit. Lithium dendrites can also form in commercial lithium-ion batteries with graphite anodes if they are improperly charged. We demonstrate that lithium dendrite growth can be studied using synchrotron-based hard X-ray microtomography. This non-destructive imaging technique allows researchers to study the growth of lithium dendrites, in addition to other morphological changes inside batteries, and subsequently develop methods to extend battery life.

When the symmetric lithium-lithium cells described above are cycled at 90 &#176;C, the voltage response looks like that shown in Figure 1. Eventually, lithium dendrites will grow through the electrolyte and cause the cell to fail by short circuit. When this happens, the voltage response to the applied current will drop down to 0.00 V. Dendrites, like the one shown in Figure 2 appear in samples that have failed by short circuit. Non-electrolyte spanning dendrites are also found in the sam...

Watch this Scientific Journal Video about Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography at JoVE.com

Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography

Synchrotron-based hard X-ray microtomography is used to image the electrochemical growth of dendrites from a lithium metal electrode through a solid polymer electrolyte membrane.

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent ...

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8.8K Views.  University of California Berkeley. Synchrotron-based hard X-ray microtomography is used to image the electrochemical growth of dendrites from a lithium metal electrode through a solid polymer electrolyte membrane.

Video: Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g.&#160;changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g.&#160;on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li-ion and Na-ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. ...

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric vehicles.1,2 However, many challenges, such as energy density and battery lifetimes, need to be overcome before this particular battery technology can be widely implemented in such applications.3 This research is challenging, and we outline a method to address these challenges using in situ NPD to probe the crystal structure of electrodes undergoing electrochemical cycling (charge/discharge) in a battery. NPD data help determine the underlying structural mechanism responsible for a range of electrode properties, and this information can direct the development of better electrodes and batteries.
We briefly review six types of battery designs custom-made for NPD experiments and detail the method to construct the &#8216;roll-over&#8217; cell that we have successfully used on the high-intensity NPD instrument, WOMBAT, at the Australian Nuclear Science and Technology Organisation (ANSTO). The design considerations and materials used for cell construction are discussed in conjunction with aspects of the actual in situ NPD experiment and initial directions are presented on how to analyze such complex in situ data.

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

We describe the design and construction of an electrochemical cell for the examination of electrode materials using in situ neutron powder diffraction (NPD). We briefly comment on alternate in situ NPD cell designs and discuss methods for the analysis of the corresponding in situ NPD data produced using this cell.

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric ...

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm2, but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample&#39;s properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 &#181;m all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

For this study synchrotron radiation micro-tomography, a non-destructive three-dimensional imaging technique, is employed to investigate an entire microelectronic package with a cross-sectional area of 16 x 16 mm. Due to the synchrotron&#39;s high flux and brightness the sample was imaged in just 3 min&#160;with an 8.7 &#181;m spatial resolution.

Synchrotron radiation micro-tomography (SR&#181;T) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data ...

Non-invasive 3D-Visualization with Sub-micron Resolution Using Synchrotron-X-ray-tomography

Little is known about the internal organization of many micro-arthropods with body sizes below 1 mm. The reasons for that are the small size and the hard cuticle which makes it difficult to use protocols of classical histology. In addition, histological sectioning destroys the sample and can therefore not be used for unique material. Hence, a non-destructive method is desirable which allows to view inside small samples without the need of sectioning.
We used synchrotron X-ray tomography at the European Synchrotron Radiation Facility (ESRF) in Grenoble (France) to non-invasively produce 3D tomographic datasets with a pixel-resolution of 0.7&micro;m. Using volume rendering software, this allows us to reconstruct the internal organization in its natural state without the artefacts produced by histological sectioning. These date can be used for quantitative morphology, landmarks, or for the visualization of animated movies to understand the structure of hidden body parts and to follow complete organ systems or tissues through the samples.

We used synchrotron X-ray tomography at the European Synchrotron Radiation Facility (ESRF) to non-invasively produce 3D tomographic datasets with a pixel-resolution of 0.7&micro;m. Using volume rendering software, this allows the reconstruction of internal structures in their natural state without the artefacts produced by histological sectioning.

Little is known about the internal organization of many micro-arthropods with body sizes below 1 mm. The reasons for that are the small size and the hard ...

Biology

Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve geologic seals and allow CO2 to escape. However, the dissolution processes at reservoir conditions are poorly understood. Thus, time-resolved experiments are needed to observe and predict the nature and rate of dissolution at the pore scale. Synchrotron fast tomography is a method of taking high-resolution time-resolved images of complex pore structures much more quickly than traditional &#181;-CT. The Diamond Lightsource Pink Beam was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 hours. The images were segmented and the porosity and permeability were measured using image analysis and network extraction. Porosity increased uniformly along the length of the sample; however, the rate of increase of both porosity and permeability slowed at later times.

Synchrotron fast tomography was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 h.

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve ...

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

Here, we present a protocol for typical experiments of soft X-ray absorption spectroscopy (sXAS) and resonant inelastic X-ray scattering (RIXS) with applications in battery material studies.

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid ...

Chemistry

Synchrotron X-ray Microdiffraction and Fluorescence Imaging of Mineral and Rock Samples

In this report, we describe a detailed procedure for acquiring and processing&#160;x-ray microfluorescence (&#956;XRF), and Laue and powder microdiffraction two-dimensional (2D) maps at beamline 12.3.2 of the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. Measurements can be performed on any sample that is less than 10 cm x 10 cm x 5 cm, with a flat exposed surface. The experimental geometry is calibrated using standard materials (elemental standards for XRF, and crystalline samples such as Si, quartz, or Al2O3 for diffraction). Samples are aligned to the focal point of the x-ray microbeam, and raster scans are performed, where each pixel of a map corresponds to one measurement, e.g., one XRF spectrum or one diffraction pattern. The data are then processed using the in-house developed software XMAS, which outputs text files, where each row corresponds to a pixel position. Representative data from moissanite and an olive snail shell are presented to demonstrate data quality, collection, and analysis strategies.

We describe a beamline setup meant to carry out rapid two-dimensional x-ray fluorescence and x-ray microdiffraction mapping of single crystal or powder samples using either Laue (polychromatic radiation) or powder (monochromatic radiation) diffraction. The resulting maps give information about strain, orientation, phase distribution, and plastic deformation.

In this report, we describe a detailed procedure for acquiring and processing&#160;x-ray microfluorescence (&#956;XRF), and Laue and powder ...

X-ray Beam Induced Current Measurements for Multi-Modal X-ray Microscopy of Solar Cells

X-ray beam induced current (XBIC) measurements allow mapping of&#160;the nanoscale performance of electronic devices such as solar cells. Ideally, XBIC is employed simultaneously with other techniques within a multi-modal X-ray microscopy approach. An example is given herein combining XBIC with X-ray fluorescence to enable point-by-point correlations of the electrical performance with chemical composition. For the highest signal-to-noise ratio in XBIC measurements, lock-in amplification plays a crucial role. By this approach, the X-ray beam is modulated by an optical chopper upstream of the sample. The modulated X-ray beam induced electrical signal is amplified and demodulated to the chopper frequency using a lock-in amplifier. By optimizing low-pass filter settings, modulation frequency, and amplification amplitudes, noise can efficiently be suppressed for the extraction of a clear XBIC signal. A similar setup can be used to measure the X-ray beam induced voltage (XBIV). Beyond standard XBIC/XBIV measurements, XBIC can be measured with bias light or bias voltage applied such that outdoor working conditions of solar cells can be reproduced during in-situ and operando measurements. Ultimately, the multi-modal and multi-dimensional evaluation of electronic devices at the nanoscale enables new insights into the complex dependencies between composition, structure, and performance, which is an important step towards solving the materials&#39; paradigm.

A setup for X-ray beam induced current measurements at synchrotron beamlines is described. It unveils the nanoscale performance of solar cells and extends the suite of techniques for multi-modal X-ray microscopy. From wiring to signal-to-noise optimization, it is shown how to perform state-of-the-art XBIC measurements at a hard X-ray microprobe.

X-ray beam induced current (XBIC) measurements allow mapping of&#160;the nanoscale performance of electronic devices such as solar cells. Ideally, XBIC is ...

Visualization of Failure and the Associated Grain-Scale Mechanical Behavior of Granular Soils under Shear using Synchrotron X-Ray Micro-Tomography

The rapid development of X-ray imaging techniques with image processing and analysis skills has enabled the acquisition of CT images of granular soils with high-spatial resolutions. Based on such CT images, grain-scale mechanical behavior such as particle kinematics (i.e., particle translations and particle rotations), strain localization and inter-particle contact evolution of granular soils can be quantitatively investigated. However, this is inaccessible using conventional experimental methods. This study demonstrates the exploration of the grain-scale mechanical behavior of a granular soil sample under triaxial compression using synchrotron X-ray micro-tomography (&#956;CT). With this method, a specially fabricated miniature loading apparatus is used to apply confining and axial stresses to the sample during the triaxial test. The apparatus is fitted into a synchrotron X-ray tomography setup so that high-spatial resolution CT images of the sample can be collected at different loading stages of the test without any disturbance to the sample. With the capability of extracting information at the macro scale (e.g., sample boundary stresses and strains from the triaxial apparatus setup) and the grain scale (e.g., grain movements and contact interactions from the CT images), this procedure provides an effective methodology to investigate the multi-scale mechanics of granular soils.

The protocol describes procedures to acquire high-spatial resolution computed tomography (CT) images of a granular soil during triaxial compression, and to apply image processing techniques to these CT images to explore the grain-scale mechanical behavior of the soil under loading.

The rapid development of X-ray imaging techniques with image processing and analysis skills has enabled the acquisition of CT images of granular soils ...

Nanoscale Characterization of Liquid-Solid Interfaces by Coupling Cryo-Focused Ion Beam Milling with Scanning Electron Microscopy and Spectroscopy

Physical and chemical processes at solid-liquid interfaces play a crucial role in many natural and technological phenomena, including catalysis, solar energy and fuel generation, and electrochemical energy storage. Nanoscale characterization of such interfaces has recently been achieved using cryogenic electron microscopy, thereby providing a new path to advancing our fundamental understanding of interface processes.
This contribution provides a practical guide to mapping the structure and chemistry of solid-liquid interfaces in materials and devices using an integrated cryogenic electron microscopy approach. In this approach, we pair cryogenic sample preparation which allows stabilization of solid-liquid interfaces with cryogenic focused ion beam (cryo-FIB) milling to create cross-sections through these complex buried structures. Cryogenic scanning electron microscopy (cryo-SEM) techniques performed in a dual-beam FIB/SEM enable direct imaging as well as chemical mapping at the nanoscale. We discuss practical challenges, strategies to overcome them, as well as protocols for obtaining optimal results. While we focus in our discussion on interfaces in energy storage devices, the methods outlined are broadly applicable to a range of fields where solid-liquid interface play a key role.

Cryogenic Focused Ion Beam (FIB) and Scanning Electron Microscopy (SEM) techniques can provide key insights into the chemistry and morphology of intact solid-liquid interfaces. Methods for preparing high quality Energy Dispersive X-ray (EDX) spectroscopic maps of such interfaces are detailed, with a focus on energy storage devices.

Physical and chemical processes at solid-liquid interfaces play a crucial role in many natural and technological phenomena, including catalysis, solar ...

Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography

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