Focused Ion Beam-scanning Electron Research Articles

Nanoscale visualization of crack tips inside molten corium-concrete interaction debris using 3D-FIB-SEM with multiphase positional misalignment correction.

Characterizing molten corium-concrete interaction (MCCI) fuel debris in Fukushima reactors is essential to develop efficient methods for its removal. To enhance the accuracy of microscopic observation and focused ion beam (FIB) microsampling of MCCI fuel debris, we developed a three-dimentional FIB scanning electron microscopy (SEM) technique with a multiphase positional misalignment (MPPM) correction method. This system automatically aligns voxel positions, corrects contrast, and removes artifacts from a series of over 500 SEM images. The MPPM correction method, which focuses on time-modulated contrast, considerably reduces charge-up artifacts in glass phases, enabling 3D morphological observation and analytical transmission electron microscopy of crack tips in two types of MCCI debris at the 3D/nanoscale for the first time. In the Fe-ZrSiO4-based debris, metallic balls composed of Fe, Cr2O3, and ZrO2 with dimples on the surface of about 2-58 µm in diameter were observed at the crack tips. In the (Zr, U)SiO4 based debris, a core-shell structure composed of a (U, Zr)O2 core with a diameter of about 1-5 μm and a (Zr, U)SiO4 shell with a diameter of about 2-9 μm in complex molten corium-concrete interaction fuel debris at the crack tips.

Antibacterial and photocatalytic activities of biosynthesized zinc oxide nanoparticle using novel plant P. macrosolen L. leaf extract

In this study, ZnO nanoparticles were produced by an easy and cost effective approach using P. macrosolen L. leaf extract and zinc chloride as Zn ion source. The as-biosynthesized ZnO nanoparticles were analyzed by powder-X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, Focused ion beam-scanning electron microscopy (FIB-SEM) and energy dispersive X-ray (EDX) characterization techniques. The XRD result revealed the formations of ZnO-nanoparticles with hexagonal structure, spherical like shape and average crystalline size of 47 nm. The presence of flavonoids in P. macrosolen L. extracts was confirmed by phytochemical tests, indicating that flavonoids primarily acted as reducing agents during nanoparticle formation. The FTIR spectrum also revealed broad and strong peaks corresponding to –OH groups, confirming the high concentration of phenolic acids present in the extract. The energy band gap of the biosynthesized ZnO Nanoparticles, calculated using the Tauc relation, was found to be 3.0 eV, indicating the presence of a blue shift. FIB-SEM was used to analyze the microstructure and identify any aggregations. The EDX analysis revealed the presence of zinc and oxygen, with weights of 16.33% and 83.67%, respectively. The disk diffusion test was performed on solid agar plates and demonstrated that the substance is effective against E. coli bacteria as an antibacterial agent. The photocatalytic degradation rate constants of the optimized ZnO samples under visible light are approximately 0.06455 min⁻1 for MO and 0.04865 min⁻1 for TB, achieving 94.47% and 92.34% degradation of MO and TB, respectively. These rates are significantly higher compared to unmodified ZnO, which has a degradation rate of 0.0075 min⁻1. The improvement in visible-light photocatalytic performance can be attributed to the formation of ZnO nanoparticles, which arise from the matching of crystal lattices and energy bands in ZnO. ZnO Nanoparticles produce excited electrons under visible light irradiation. These excited electrons in the ZnO nanoparticles are directly transferred to the conduction band (CB), resulting in notable visible light photocatalytic performance.

Photonic Band Gap Engineering by Varying the Inverse Opal Wall Thickness.

We demonstrate the band gap programming of inverse opals by fabrication of different wall thickness by atomic layer deposition (ALD). The opal templates were synthesized using polystyrene and carbon nanospheres by the vertical deposition method. The structure and properties of the TiO2 inverse opal samples were investigated using Scanning Electron Microscope (SEM) and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), Energy Dispersive X-ray analysis (EDX), X-ray Diffraction (XRD) and Finite Difference Time Domain (FDTD) simulations. The photonic properties can be well detected by UV-Vis reflectance spectroscopy, while diffuse reflectance spectroscopy appears to be less sensitive. The samples showed visible light photocatalytic properties using Raman microscopy and UV-Visible spectrophotometry, and a newly developed digital photography-based detection method to track dye degradation. In our work, we stretch the boundaries of a working inverse opal to make it commercially more available while avoiding fully filling and using cheaper, but lower-quality, carbon nanosphere sacrificial templates.

Influence of Local Environment Under Polarization on Wettability of Ni/YSZ Interface

In solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs), degradation of hydrogen electrode during long–term operation is one of the issues to be solved. Migration and aggregation of Ni particles are major factors of this degradation, and especially after steam electrolysis operation, intense Ni migration has been observed at the hydrogen electrode/electrolyte interface [1]. This phenomenon is assumed to be related to the change in wettability of the Ni/electrolyte interface under polarization [2]. A quantitative measurement of interface wettability is the concept of contact angle. It is known that the contact angle is determined by the balance between the surface tension of contacting materials and the interfacial tension. Contact angle analysis is usually used for liquid–solid interfaces, but it has also been suggested to be useful for the characterization of solid metal–oxide interfaces [3]. Therefore, the aim of this study was to directly measure the contact angle between Ni and YSZ electrolyte under various conditions in order to quantify the changes in wettability at the interface.Ni thin film electrodes were prepared by sputtering Ni on YSZ electrolyte. Using this model electrode, electrochemical measurements were performed under open circuit holding or a potentiostatic operation (SOFC operation or SOEC operation) at high temperatures. Subsequently, postmorterm analysis of the samples was performed using a Focused Ion Beam–Scanning Electron Microscope (FIB–SEM). Using the cross–sectional SEM images of the model electrode, the contact angle was calculated by distinguishing the three phases of Ni, YSZ, and pores based on the difference in contrast of each phase. The analysis revealed that the wettability of the Ni/YSZ electrolyte interface changed depending on the operation mode. Specifically, the contact angle after SOEC operation increased compared to values after open circuit holding or SOFC operation. This phenomenon is thought to be related to changes in oxygen potential.AcknowledgementsThis paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Microstructural Analysis of Stainless Steel Support/Ni-YSZ Anode Interface in Metal-Supported SOFCs

Solid oxide fuel cells (SOFCs) have attracted attention due to their high energy conversion efficiency and fuel flexibility. However, conventional anode-supported SOFCs composed solely of ceramics are susceptible to thermal stress such as rapid temperature rises and drops, which can cause cell cracks. Therefore, metal-supported SOFCs (MS-SOFCs) have been devised that use a stainless steel with excellent heat resistance as a support. In MS-SOFCs, elemental diffusion from the metal support during the cell manufacturing process causes microstructural changes in electrodes, leading to a reduction in cell performance [1, 2]. Although the microstructure and diffusion state of elements at the support layer/anode interface are different from those of conventional anode-supported cells, the phenomena as well as the chemical and physical states that occur at the interface have not been sufficiently studied. In this study, then, the microstructural characteristics of the stainless steel support/anode interface were quantitatively analyzed to understand the phenomena occurring and to develop methods to suppress the diffusion of metallic elements.Gd-doped CeO2 (GDC) was coated as a diffusion barrier layer (DBL) on a SUS430 stainless steel substrate by magnetron sputtering, followed by the NiO-YSZ (8 mol% Y2O3-ZrO2) slurry coating. The composition of SUS430 is given in Table 1. Samples without DBL were also fabricated. These samples were sintered at 1250 ºC for 10 hours in 50% H2-50% Ar. Three-dimensional reconstruction of the microstructures of these samples was performed using a focused ion beam-scanning electron microscope (FIB-SEM), and microstructural parameters were calculated. In addition, elemental diffusion at the interface was analyzed using an energy dispersive X-ray spectroscopy (EDS) analysis.When the sample was sintered at 1250 °C in a reducing atmosphere, the diffusion of Fe was significantly suppressed by the insertion of DBL. Therefore, it was confirmed that the GDC layer is effective to suppress the Fe diffusion as well as to prevent the formation of solid solution with Ni. However, no significant difference in Cr diffusion was observed. Furthermore, SEM observation revealed that the Ni surface was partially covered with Mn-Cr oxides. The formation of such a characteristic structure had a negative effect to reduce the effective triple phase boundary (TPB) length of the anode. Thus, it was concluded that the insertion of GDC layer suppressed the formation of Ni-Fe solid solution, while the patrial coverage of the Ni surface with Mn-Cr oxides reduced the effective TPB length.AcknowledgementsThis paper is based on results obtained from a project, JPNP20003, commissioned by the New Energy and Industrial Technology Development Organization (NEDO).[1] M.C. Tucker, J. Power Sources, 195, 15 (2010).[2] T. Franco, et al., ECS Transactions, 7, 771, (2007). Figure 1

Three-Dimensional Imaging of Large-Volume Lithium Metal Microstructure by Xenon Plasma Focused Ion Beam

Advanced energy storage systems are increasingly in demand due to the rising needs of portable electronics, electric vehicles, and grid-scale energy storage. Lithium (Li) metal stands out as an exceptional battery anode with its high theoretical specific capacity (3860 mA g-1 compared to graphite's 372 mA g-1) and low redox potential (-3.04 V vs. the standard hydrogen electrode). However, practical Li metal anodes often face challenges such as low Coulombic efficiency, short cycle life, and safety concerns, mainly due to the reactive nature of Li metal and the unpredictable deposition with diverse morphologies.Developing advanced Li metal anodes requires a deep understanding of their electrode structure. It is indispensable to find three-dimensional (3D) images. However, obtaining accurate 3D imaging of Li anodes poses significant challenges. On one hand, the non-uniform electrodeposition of Li metal necessitates a large sample to accurately represent the entire electrode. On the other hand, achieving high resolution is essential for distinguishing the complex phases within the Li electrode, including metallic Li, solid electrolyte interphase (SEI), and pores. While popular 3D imaging technologies like X-ray computed tomography and nuclear magnetic resonance imaging offer comprehensive size information, they often struggle with limitations in resolution or imaging contrast. Traditional focused ion beam-scanning electron microscopy (FIB/SEM) can provide high-resolution images at nanoscale, but its use of gallium ion (Ga+) leads to issues such as ion implantation and limited size (≤ 10 μm). An emerging alternative, plasma FIB/SEM (PFIB/SEM), coupled with Xenon (Xe) gas, featured by both high resolution and large volume size, presents a promising solution, making it appealing for characterization of Li electrode.In this presentation, Xe PFIB is employed for 3D imaging of electrodeposited Li with a large volume (200 μm in dimension) and high resolution (50 nm per pixel). This approach facilitates the clear identification of two phases: deposited Li metal and SEI/pores. It enables the quantification of their spatial distribution, packing density, and specific surface area, crucial parameters determining the Coulombic efficiency of the deposited Li anode. Furthermore, the ability to separate individual Li particles provides quantitative information on volume size, particle number, and shape. These quantitative results establish a robust mathematical relationship with the overpotential of Li deposition, significantly enhancing our understanding of the Li electrodeposition process.Leveraging the large volume and high-resolution 3D information obtained through Xe PFIB-SEM, this work demonstrates its significance in assessing and understanding electrodeposited Li, offering valuable insights for designing advanced Li metal anodes. Xe PFIB-SEM methodology is poised to become a pivotal technique for 3D characterization in energy storage materials and related fields.

Application of Advanced Microscopy Techniques to the Characterization of Mixed Matrix Membranes.

Mixed matrix membranes (MMMs) have emerged as promising materials for various separation processes due to their tunable properties, enhanced separation performance and reproducibility. In this review paper, we provide a comprehensive overview of the methodologies, challenges, and applications associated with the characterization of MMMs using two advanced imaging techniques: Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) and Transmission Electron Microscopy (TEM). We begin by outlining the principles and capabilities of FIB-SEM and TEM, emphasizing their suitability for studying the microstructure, morphology, and composition of MMMs at nanoscale resolution. Subsequently, we discuss the specific challenges and limitations encountered in the characterization of MMMs using these techniques, including sample preparation, image acquisition, and data interpretation. Furthermore, we review the diverse applications of FIB-SEM and TEM in elucidating the structure-property relationships of MMMs. Through illustrative examples, we highlight the valuable insights gained from these imaging techniques in optimizing MMMs for various separation applications. Finally, we propose future directions and emerging trends in MMM characterization, including the integration of lasers into FIB-SEM and in situ characterization techniques, to address current challenges and push the boundaries of MMM design and performance. Overall, this review provides a comprehensive overview of the state-of-the-art methodologies for characterizing MMMs using FIB-SEM and TEM, identifies key challenges, and offers insights into future research directions aimed at harnessing the full potential of MMMs for sustainable separation technologies.

Correlating Heterogeneities in Support Fragmentation to Polymer Morphology in Metallocene‐Based Propylene Polymerization Catalysis

AbstractIn the field of olefin polymerization catalysis, metallocenes are heterogenized with methylaluminoxane onto silica supports to yield active catalysts. During olefin polymerization, these silica supports act as a framework to control the fragmentation stage, thereby influencing the final polymer product and preventing reactor fouling and fines formation. This study investigates the influence of different silica supports induced on the final polymer product. To study a broad range of silica supports from an industrial silica database, we utilize a hierarchical clustering method to cluster the supports based on their physical properties. From the clustering method, five supports representing the clusters and an industrial benchmark were analyzed at different polymerization stages using focused ion beam–scanning electron microscopy (FIB–SEM) and microcomputed tomography (microCT). This combined FIB‐SEM/microCT methodology revealed differences in both fragmentation behavior and polymer morphologies based on structural features, including macropores, mesopores, spray‐dried shells, spray‐dried spheres, and denser shells. The heterogeneity and ideal fragmentation behavior was further assessed by calculating the replication factor of each support, indicating that silica materials containing macropores and spray‐dried shells have an almost ideal replication phenomenon. This multiscale analysis revealed new understanding of catalyst fragmentation for different supports. This understanding could in the future be further developed by the addition of more supports or additional analysis of the supports to the industrial database.

3D microstructure reconstruction and characterization of porous materials using a cross-sectional SEM image and deep learning

Accurate assessment of the three-dimensional (3D) pore characteristics within porous materials and devices holds significant importance. Compared to high-cost experimental approaches, this study introduces an alternative method: utilizing a generative adversarial network (GAN) to reconstruct a 3D pore microstructure. Unlike some existing GAN models that require 3D images as training data, the proposed model only requires a single cross-sectional image for 3D reconstruction. Using porous ceramic electrode materials as a case study, a comparison between the GAN-generated microstructures and those reconstructed through focused ion beam-scanning electron microscopy (FIB-SEM) reveals promising consistency. The GAN-based reconstruction technique demonstrates its effectiveness by successfully characterizing pore attributes in porous ceramics, with measurements of porosity, pore size, and tortuosity factor exhibiting notable agreement with the results obtained from mercury intrusion porosimetry.

Oxidation progress and inner structure during single micron-sized iron particles combustion in a hot oxidizing atmosphere

The present experimental study focuses on the determination of the oxidation progress and internal structures during the combustion of single iron particles using combined in-situ optical measurements and ex-situ material examination of rapidly quenched particles. Narrowly sieved iron particles with a mean diameter of 49µm are ignited and burn in the hot exhaust of a premixed CH4/O2/N2 flat flame with remaining 20vol% O2, provided by a laminar flow reactor with well-defined thermal and flow boundary conditions. During particle combustion, key parameters of oxidation progress are determined optically in a time-resolved manner, such as the time-resolved particle surface temperature and the reaction time relative to the instant of the particle peak temperature. Furthermore, individually burning particles are rapidly quenched at different combustion stages and then extracted from the exhaust gas using an isokinetic extraction probe. The bulk composition of the quenched particles with respect to α-Fe and its three oxides FeO, Fe3O4, and Fe2O3 is determined using Wide-angle X-ray Scattering and 57Fe Mössbauer Spectroscopy. Combining the information obtained from in-situ and ex-situ measurements, it is shown that iron particles oxidize rapidly to FeO during the initial stage of combustion, followed by a much slower oxidation to Fe3O4 as the particles cool down. The peak particle temperatures are measured during the fast initial oxidation. Finally, particles sampled from representative positions of the oxidation process are analyzed by Energy-Dispersive X-ray Spectroscopy and Focused Ion Beam Scanning Electron Microscopy, revealing different particle morphology and internal structures. For the first time, the clear presence of an oxide shell and iron-core structure in quenched particles suggests that liquid iron and liquid iron oxide are layered during liquid phase combustion, if the particle remains within the miscible gap.

Characterization of human trabecular bone across multiple length scales using a correlative approach combining X-ray tomography with LaserFIB and plasma FIB-SEM

Three-dimensional correlative multimodal and multiscale imaging is an emerging method for investigating the complex hierarchical structure of biological materials such as bone. This approach synthesizes images acquired across multiple length scales, for the same region of interest, to provide a comprehensive view of the material structure of a sample. Here, we develop a workflow for the structural analysis of human trabecular bone using a femtosecond laser to produce a precise grid to facilitate correlation between imaging modalities and identification of structures of interest, in this case, a single trabecula within a volume of trabecular bone. Through such image registration, high resolution X-ray microscopy imaging revealed fine architectural details, including the cement sheath and bone cell lacunae of the selected bone trabecula. The selected bone volume was exposed with a combination of manual polishing and site-specific femtosecond laser ablation and then examined with plasma focused ion beam-scanning electron microscopy. This reliable and versatile correlation approach has the potential to be applied to a variety of biological tissues and traditional engineered materials. The proposed workflow has the enhanced capability for generating highly resolved and broadly contextualized structural data for a better understanding of the architectural features of a material spanning its macroscopic to nanoscopic levels.

Volume electron microscopy reveals 3D synaptic nanoarchitecture in postmortem human prefrontal cortex.

Synaptic function is directly reflected in quantifiable ultrastructural features using electron microscopy (EM) approaches. This coupling of synaptic function and ultrastructure suggests that in vivo synaptic function can be inferred from EM analysis of ex vivo human brain tissue. To investigate this, we employed focused ion beam-scanning electron microscopy (FIB-SEM), a volume EM (VEM) approach, to generate ultrafine-resolution, three-dimensional (3D) micrographic datasets of postmortem human dorsolateral prefrontal cortex (DLPFC), a region with cytoarchitectonic characteristics distinct to human brain. Synaptic, sub-synaptic, and organelle measures were highly consistent with findings from experimental models that are free from antemortem or postmortem effects. Further, 3D neuropil reconstruction revealed a unique, ultrastructurally-complex, spiny dendritic shaft that exhibited features characteristic of heightened synaptic communication, integration, and plasticity. Altogether, our findings provide critical proof-of-concept data demonstrating that ex vivo VEM analysis is an effective approach to infer in vivo synaptic functioning in human brain.

Video frame interpolation neural network for 3D tomography across different length scales

Three-dimensional (3D) tomography is a powerful investigative tool for many scientific domains, going from materials science, to engineering, to medicine. Many factors may limit the 3D resolution, often spatially anisotropic, compromising the precision of the information retrievable. A neural network, designed for video-frame interpolation, is employed to enhance tomographic images, achieving cubic-voxel resolution. The method is applied to distinct domains: the investigation of the morphology of printed graphene nanosheets networks, obtained via focused ion beam-scanning electron microscope (FIB-SEM), magnetic resonance imaging of the human brain, and X-ray computed tomography scans of the abdomen. The accuracy of the 3D tomographic maps can be quantified through computer-vision metrics, but most importantly with the precision on the physical quantities retrievable from the reconstructions, in the case of FIB-SEM the porosity, tortuosity, and effective diffusivity. This work showcases a versatile image-augmentation strategy for optimizing 3D tomography acquisition conditions, while preserving the information content.

Tuning α precipitation via post-heat treatments in direct energy deposited metastable β Ti-5Al-5Mo-5V-3Cr alloy and its impact on mechanical properties

In this study, the strength and ductility of a direct energy deposited (DEDed) metastable β Ti-5Al-5Mo-5 V-3Cr (wt%, Ti-5553) alloy was explored by tuning the formation of various α microstructures through post-heat treatments. The microstructure of DEDed Ti-5553 with and without post-heat treatments was systematically studied using scanning electron microscopy, three-dimensional (3D) focused ion beam-scanning electron microscopy tomography, transmission electron microscopy, scanning transmission electron microscopy, and atom probe tomography. Nanoscale ω phase and O′ phase particles were observed in the as-built DEDed Ti-5553 without post-heat treatment for the first time. By altering the aging temperatures and heating rates during post-heat treatments, various microstructural evolution pathways were activated, leading to α microstructures with different sizescales, morphologies, and number densities. By fast heating and isothermal aging at 600°C for 2 hours, refined α microstructure was formed through the pseudospinodal decomposition mechanism. While slow heating (at the heating rates of 5 °C/min or 0.5 °C/min) to 600°C and isothermal aging for 2 hours, super-refined α microstructures were produced respectively, primarily via ω-assisted and O′-assisted α precipitation mechanisms. By fast heating to and isothermal aging at 700°C, fine-scaled intragranular α microstructure was formed, dramatically different in morphology and sizescale from the coarse α microstructure formed in the casted Ti-5553, which is suspected to be related to the indirect influence of nanoscale isothermal ω phase particles formed during the DED process and the excess oxygen introduced during the DED process. With fast heating to and isothermal aging at 800°C, coarse α microstructure forms through the classical nucleation and growth mechanism. Various α microstructures led to a drastic change of mechanical properties with improvements up to a 55 % increase in hardness and 92 % increase in tensile yield strength, compared with as-built DEDed Ti-5553. Our work indicates the feasibility of achieving tailored mechanical properties in DEDed metastable β-Ti alloys by tuning α microstructures through selectively activating various phase transformation mechanisms via post-heat treatments.

Mass Transport Regimes in a CO2R Gas Diffusion Electrode Pore with Coupled Microkinetics Model

Gas Diffusion Electrodes (GDEs) have arisen as a popular CO2 electrolyser configuration due to the improved mass transfer properties and higher current densities possible in comparison to a liquid-fed system. In this work, we aim to understand the mass transport regimes in a single liquid-filled pore of a GDE, i.e., an idealized model of the porous catalyst layer. In previous work, Butler-Volmer (BV) expressions have been used to model the CO evolution reaction and the Hydrogen Evolution Reaction (HER). In this study, we extend that in a few ways: (1) a MicroKinetic Model (MKM) of Au at the surface of the electrode is used instead of the BV expressions, (2) volume/steric effects are incorporated through the Generalized Modified Poisson-Nerst-Planck (GMPNP) equation, and (3) more reactions are considered in the electrolyte. By analyzing pores of varying sizes, following the size distribution measured by Focused Ion Beam Scanning Electron Microscopy (FIB/SEM) in a GDE from the literature, we assess conditions where concentration profiles are no longer effectively one-dimensional in the pore axis. We discuss how these three-dimensional mass transfer effects impact CO2 conversion efficiency. In such regimes, we describe why special treatment is required when calling BV expressions in macroscale pore-averaged models.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL release number: LLNL-ABS-858384.

Understanding the Phenomenon of High Temperature Hydrogen Attack (HTHA) Responsible for Ferrito-Pearlitic Steels Damage

This article focuses on the fine characterization of steels commonly used in the petrochemical industry damaged by the phenomenon of high temperature hydrogen attack (HTHA). The study was conducted in two steps. To begin with, a damaged 0.5-Mo pearlitic steel from the petroleum refineries, submitted to HTHA for decades, was characterized in detail using multiscale electron microscopy techniques. As part of an upstream study to better understand the onset and the growth of cavities, a brand new SA516 grade 60 low carbon–manganese steel was subsequently exposed to accelerated HTHA conditions through interrupted cycles carried out in autoclaves and then examined. Numerous cavities, plausibly filled with methane, were noticed in both materials. These cavities were mostly located at ferrite–pearlite grain boundaries along carbides and at triple grain boundaries near large carbides. The 0.5-Mo pearlitic steel showed cavities reaching significant sizes, up to 1 µm, but surprisingly no cracks were observed in the depth of the pipe. The major outcome is that 3D focused ion beam–scanning electron microscopy combined with transmission electron microscopy (TEM) analyses unveiled different natures of precipitates as well as in and nearby HTHA cavities for both 0.5-Mo and low carbon–manganese steels. Inclusions, likely AlN, but also Mo- and Cu-rich precipitates were observed in cavities of the industrial steel. These results confirmed a previous study performed on a similar industrial steel that drew a possible correlation between cavities nucleation and the intersection of transgranular inclusion-enriched plane with a grain boundary or carbides in pearlite grains (Flament in Microscopy and Microanalysis 28:1602–1604, 2022).

Three-dimensional structural analyses of the oxygen electrodes in solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) have garnered interest as efficient devices for production of clean fuel such as hydrogen gas. However, the industrialization of SOEC technology has encountered significant challenges, such as unsatisfactory performance and insufficient durability. In this study, we aimed to improve the electrochemical performance and stability of the SOEC air electrode by modifying it at various annealing temperatures (900, 1000, and 1100 °C). Electrochemical testing revealed that the SOEC cell with the electrode annealed at 1000 °C for 1 h exhibited the highest current density of 0.88 A/cm2 at 750 °C and 1.3 V, which is 1.76-times higher than that of the cell with the unoptimized electrode annealed at 900 °C. Three-dimensional microstructural analyses using Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) confirmed that the optimized cell is the most porous with sufficient pore surface area, thereby facilitating electrochemical reactions and gas transport, and preventing delamination of the air electrode resulting from lower oxygen partial pressure difference between the barrier layer and air/electrode interface. Side reactions at the interface, including the generation of resistant SrZrO3, are concurrently avoided. These findings demonstrate the potential of the modified SOEC air electrode for improving electrochemical performance and stability.

Combining ternary, ionic liquid-based, polymer electrolytes with a single-ion conducting polymer-based interlayer for lithium metal batteries

Among the many approaches to improve the performance of lithium-metal batteries, ternary polyethylene oxide/ionic liquid/lithium salt electrolytes offer several advantages such as low flammability, high conductivity (vs. polyethylene oxide/lithium salt electrolytes) and, to a large extent, limiting the growth of dendrites at moderate currents. However, they suffer from relatively low mechanical strength for lithium metal confinement. Besides, the lithium transport numbers are very low, which is conducive to lithium depletion during plating at high current densities at the lithium/electrolyte interface. Thus, we show here that the combination of a ternary solid polymer electrolyte with a single-ion polymer-based conducting interlayer allows for a significant improvement of the cyclability of the lithium metal anode. This results in a strong improvement of the electrochemical performance of lithium-metal batteries using solid polymer electrolytes at 80 °C, with an 85% capacity retention after 350 cycles (vs. 60% after 62 cycles for the uncoated anode). This is attributed, via focused ion beam-scanning electron microscopy and X-ray photoelectron spectroscopy, to a denser lithium deposit, better contact with the electrolyte and a reduced reactivity of electrolyte species with the interlayer.

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Porosity and Organic Content in the Tuscaloosa Marine Shale: Insights from Focused Ion Beam-Scanning Electron Microscopy Characterization

Characterizing PEM fuel cell catalyst layer properties from high resolution three-dimensional digital images, part I: A numerical procedure for the ionomer distribution reconstruction

In this work, a numerical approach is presented to reconstruct the ionomer three-dimensional distribution in the microstructure of the cathode catalyst layer (CCL) of a polymer electrolyte membrane fuel cell (PEMFC) from a 3D segmented image of the CCL obtained by focused ion beam-scanning electron microscopy (FIB-SEM). Three forms of ionomer are distinguished: the ionomer filaments, the coating ionomer and the inter-carbon grains ionomer. The ionomer filaments are identified by applying a filtering procedure to the size distribution in the segmented solid phase obtained via a maximum sphere inscription algorithm. The coating ionomer is reconstructed via a filtering procedure of the curvature distribution computed over the interface between the two segmented phases from the consideration that concave regions are preferential ionomer accumulation zones during the drying step of the CCL fabrication procedure. This procedure of coating controlled by the local curvature is applied until a desired value of coverage is reached. In a last step, catalyst nanoparticles, also not visible in the FIB-SEM image, are reconstructed in the image.