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Developing new methods that reveal the structure of electrode materials under polarization is key to constructing robust structure-property relationships. However, many existing methods lack the spatial resolution in structural changes and fidelity to electrochemical operating conditions that are needed to probe catalytically relevant structures. Here, we combine a nanopipette electrochemical cell with three-dimensional X-ray Bragg coherent diffractive imaging to study how strain in a single Pt grain evolves in response to applied potential. During polarization, marked changes in surface strain arise from the Coulombic attraction between the surface charge on the electrode and the electrolyte ions in the electrochemical double layers, while the strain in the bulk of the crystal remains unchanged. The concurrent surface redox reactions have a strong influence on the magnitude and nature of the strain changes under polarization. Our studies provide a powerful blueprint to understand how structural evolution influences electrochemical performance at the nanoscale.

Purpose The purpose of this study is to empirically explore the interaction between corporate philanthropy and firm performance through the mechanism of corporate strategies, such as unrelated diversification and global strategic posture (GSP). Design/methodology/approach A theoretical framework was developed based on institutional theory to argue that GSP can play an important mediating role in the relationship between corporate philanthropy and firm performance. PROCESS macro for SPSS and SAS to test a mediation was conducted using data from 115 publicly traded US firms between 2010 and 2017. Findings This study verified that GSP acts as an indirect mediator that influences the relationship between corporate philanthropy and firm performance. However, unrelated diversification was not found to be a mediator of that relationship. Research limitations/implications This study has extended the current understanding of institutional theory to explain the relationship between corporate philanthropy and corporate strategies. Practical implications This study helps to provide corporate managers with a promising notion that corporate philanthropy can help firms with market entry strategies. Originality/value This study helps to provide empirical evidence on the relationships among corporate philanthropy, corporate strategies and firm performance. Specifically, the finding of this study indicates strategic conditions under which the firm’s philanthropic efforts are more likely to influence firm performance.

As a critical component of coherent X-ray diffraction imaging (CDI), phase retrieval has been extensively applied in X-ray structural science to recover the 3D morphological information inside measured particles. Despite meeting all the oversampling requirements of Sayre and Shannon, current phase retrieval approaches still have trouble achieving a unique inversion of experimental data in the presence of noise. Here, we propose to overcome this limitation by incorporating a 3D Machine Learning (ML) model combining (optional) supervised learning with transfer learning. The trained ML model can rapidly provide an immediate result with high accuracy which could benefit real-time experiments, and the predicted result can be further refined with transfer learning. More significantly, the proposed ML model can be used without any prior training to learn the missing phases of an image based on minimization of an appropriate ‘loss function’ alone. We demonstrate significantly improved performance with experimental Bragg CDI data over traditional iterative phase retrieval algorithms.

Palladium absorbs large volumetric quantities of hydrogen at room temperature and ambient pressure, making the palladium hydride system a promising candidate for hydrogen storage. Here, we use Bragg coherent diffraction imaging to map the strain associated with defects in three dimensions before and during the hydride phase transformation of an individual octahedral palladium nanoparticle, synthesized using a seed-mediated approach. The displacement distribution imaging unveils the location of the seed nanoparticle in the final nanocrystal. By comparing our experimental results with a finite-element model, we verify that the seed nanoparticle causes a characteristic displacement distribution of the larger nanocrystal. During the hydrogen exposure, the hydride phase is predominantly formed on one tip of the octahedra, where there is a high number of lower coordinated Pd atoms. Our experimental and theoretical results provide an unambiguous method for future structure optimization of seed-mediated nanoparticle growth and in the design of palladium-based hydrogen storage systems. Palladium can absorb high volumes of hydrogen, but the morphology and 3D displacements occurring during palladium hydride phase formation are not fully characterized in the literature. Here, the authors use Bragg coherent diffraction imaging to map the strain within an individual palladium nanoparticle before and during hydride phase transformation, identifying a characteristic displacement caused by the seed particle in the nanocrystal.

All-solid-state lithium batteries promise significant improvements in energy density and safety over traditional liquid electrolyte batteries. The Al-doped Li7La3Zr2O12 (LLZO) solid-state electrolyte shows excellent potential given its high ionic conductivity and good thermal, chemical, and electrochemical stability. Nevertheless, further improvements on electrochemical and mechanical properties of LLZO call for an in-depth understanding of its local microstructure. Here, we employ Bragg coherent diffractive imaging to investigate the atomic displacements inside single grains of LLZO with various Al-doping concentrations, resulting in cubic, tetragonal, and cubic-tetragonal mixed structures. We observe coexisting domains of different crystallographic orientations in the tetragonal structure. We further show that Al doping leads to crystal defects such as dislocations and phase boundaries in the mixed- and cubic-phase grain. This study addresses the effect of Al doping on the nanoscale structure within individual grains of LLZO, which is informative for the future development of solid-state batteries.

Focused ion beam (FIB) techniques are commonly used to machine, analyse and image materials at the micro- and nanoscale. However, FIB modifies the integrity of the sample by creating defects that cause lattice distortions. Methods have been developed to reduce FIB-induced strain, however these protocols need to be evaluated for their effectiveness. Here we use non-destructive Bragg coherent X-ray diffraction imaging to study the in situ annealing of FIB-milled gold microcrystals. We simultaneously measure two non-collinear reflections for two different crystals during a single annealing cycle, demonstrating the ability to reliably track the location of multiple Bragg peaks during thermal annealing. The thermal lattice expansion of each crystal is used to calculate the local temperature. This is compared to thermocouple readings, which are shown to be substantially affected by thermal resistance. To evaluate the annealing process, we analyse each reflection by considering facet area evolution, cross-correlation maps of displacement field and binarised morphology, and average strain plots. The crystal's strain and morphology evolve with increasing temperature, which is likely to be caused by the diffusion of gallium in gold below ~280{\deg}C and the self-diffusion of gold above ~280{\deg}C. The majority of FIB-induced strains are removed by 380-410\degree C, depending on which reflection is being considered. Our observations highlight the importance of measuring multiple reflections to unambiguously interpret material behaviour., Comment: 51 pages, 16 figures

PurposeThis study aims to investigate the role of firm age in the relationship between CEO characteristics (measured by founder status and civic engagement) and the level of corporate philanthropy which is one of the important components of corporate social responsibility (CSR) practices (Carroll, 1991).Design/methodology/approachDrawing from upper echelons theory, this study argues that firm age functions as a barrier that limits the relationship between CEO characteristics and the level of corporate philanthropy. Moderated regression analysis (MRA) was used to analyze data from 146 publicly traded US firms between 2010 and 2017.FindingsThis study verified that there is a significantly positive relationship between CEO civic engagement and the level of corporate philanthropy although the relationship between CEO founder status and the level of corporate philanthropy was not found to be significant. Specifically, the relationship between CEO characteristics and the level of corporate philanthropy was weaker as firms get older. Overall, the results indicate that the organizational inertia of older firms can restrict the effect of CEO characteristics on corporate philanthropy.Research limitations/implicationsThis study provides new insight into the underlying mechanisms between CEOs and firm age. This study also suggests that CEOs interpret corporate philanthropy as an important part of their civic engagement which broadly supports business legitimacy for their firm.Practical implicationsThis study provides lessons for executive selection and succession decisions toward CSR strategies. Specifically, this study provides a practical foundation of how executives’ civic engagement can be related to corporate philanthropy as an important dimension of CSR practices. Furthermore, this study suggests that shareholders pay more attention to the ultimate decision-maker, the CEO, in an organization as his or her background characteristics can reflect a firm’s social responsibility initiatives, including corporate philanthropy.Originality/valueThis study contributes to on-going scholarly work in the field of strategic leadership and corporate philanthropy literature. In addition, this study provides empirical evidence to the nature of scholarly conversations regarding the role of firm age in shaping the relationship between CEO characteristics and corporate philanthropy.

Corrosion is a major concern for many industries, as corrosive environments can induce structural and morphological changes that lead to material dissolution and accelerate material failure. The progression of corrosion depends on nanoscale morphology, stress, and defects present. Experimentally monitoring this complex interplay is challenging. Here we implement in situ Bragg coherent X-ray diffraction imaging (BCDI) to probe the dissolution of a Co–Fe alloy microcrystal exposed to hydrochloric acid (HCl). By measuring five Bragg reflections from a single isolated microcrystal at ambient conditions, we compare the full three-dimensional (3D) strain state before corrosion and the strain along the [111] direction throughout the corrosion process. We find that the strained surface layer of the crystal dissolves to leave a progressively less strained surface. Interestingly, the average strain closer to the centre of the crystal increases during the corrosion process. We determine the localised corrosion rate from BCDI data, revealing the preferential dissolution of facets more exposed to the acid stream, highlighting an experimental geometry effect. These results bring new perspectives to understanding the interplay between crystal strain, morphology, and corrosion; a prerequisite for the design of more corrosion-resistant materials.

Lithium uptake and release in lithium titanate (LTO) anode materials during a discharge and charge cycle is one of the fundamental processes of a lithium-ion battery (LIB), still not fully understood at the microscopic level. During the discharge cycle, LTO undergoes a phase transformation between Li4Ti5O12 and Li7Ti5O12 states within a cubic crystal lattice. To reveal the details of the microscopic mechanism, it is necessary to track the sequence of phase transformations at different discharge/charge states under operating conditions. Here, we use in situ Bragg coherent diffraction imaging (BCDI) and in situ X-ray diffraction (XRD) experiments to examine the lithium insertion-induced materials phase transformation within a single LTO particle and a bulk battery analogue, respectively. BCDI analysis from (111) Bragg peak shows the two-phase transformation manifesting as a distinct image phase modulation within a single LTO nanoparticle occurring in the middle of the discharge region then subsiding toward the end of the discharge cycle. We observe the biggest phase variation at the two-phase stage, indicating the formation of phase domains of 200 nm in size during the discharge process. We also observe a lattice contraction of >0.2% in a single LTO nanoparticle at the (400) Bragg peak measurement, larger than that in the corresponding bulk material. Our observation of this phase transformation at a single-particle level has implications for the understanding of the microscopic/mesoscale picture of the phase transformation in anode and cathode LIBs materials.

Fundamental understanding of structural changes during catalytic reactions is crucial to understanding the underlying mechanisms and optimizing efficiencies. Surface energy and related catalytic mechanisms are widely studied. However, the catalyst lattice deformation induced by catalytic processes is not well understood. Here, we study the strain in an individual platinum (Pt) nanoparticle (NP) using Bragg coherent diffraction imaging under in situ oxidation and reduction reactions. When Pt NPs are exposed to H

Purpose This study aims to explore the effects of consumer resilience and brand familiarity on the relationship between corporate social responsibility (CSR) and consumer attitudes toward the company conducting CSR in places that have suffered from traumatic events such as natural or anthropogenic disasters and uncertainty of public health issue. Design/methodology/approach This study collected survey-based data from 194 participants who suffered from natural and anthropogenic disasters in the state of Texas. Path analysis was used to test each structural relationship among variables after verifying the reliability and validity of each variable. Analysis of variance was used to investigate the difference in resilience between the two groups. Findings This study verified that there is a positive relationship between CSR and consumer attitude. More importantly, the results show that both resilience and familiarity play an important role as a mediator in the relationship between CSR and attitudes. In particular, it tells us that a group with high resilience shows a higher possibility of having positive attitudes toward the company than another group having low resilience. Originality/value This study empirically tested the impacts of CSR, resilience and brand familiarity on building consumer attitudes. Furthermore, this study explored the effects of resilience and brand familiarity on the relationship between CSR and attitudes. Thus, this study was able to contribute to understanding the effects of CSR, resilience and familiarity on building a positive attitude in the specific settings, in terms of traumatic events, theoretically and practically.

Understanding catalysts strain dynamic behaviours is crucial for the development of cost-effective, efficient, stable and long-lasting catalysts. Here, we reveal in situ three-dimensional strain evolution of single gold nanocrystals during a catalytic CO oxidation reaction under operando conditions with coherent X-ray diffractive imaging. We report direct observation of anisotropic strain dynamics at the nanoscale, where identically crystallographically-oriented facets are qualitatively differently affected by strain leading to preferential active sites formation. Interestingly, the single nanoparticle elastic energy landscape, which we map with attojoule precision, depends on heating versus cooling cycles. The hysteresis observed at the single particle level is following the normal/inverse hysteresis loops of the catalytic performances. This approach opens a powerful avenue for studying, at the single particle level, catalytic nanomaterials and deactivation processes under operando conditions that will enable profound insights into nanoscale catalytic mechanisms., Direct visualisation of site-specific strain variations of catalysts is needed to better understand catalytic properties. Here, the authors determine with attojoule precision that the well-known catalytic hysteresis phenomenon occurs at single particle level and involves three-dimensional strain field.

Summary Halide perovskites have emerged as a new class of inorganic-based soft semiconductors that are revolutionizing the field of (opto)electronics. However, the fundamental structures and properties or functions of halide perovskites are still far from being fully understood, calling for the need of precise, quantitative, and high-spatiotemporal-resolution characterizations. As one of the most powerful multimodal characterization techniques, synchrotron radiation offers high-brilliance X-ray beams for high-resolution observations across multiple length scales obtained within extremely short time spans. Performing a brief review of synchrotron-based perovskite studies in the literature, here we provide perspectives on the use of synchrotron characterizations not only for studying multiple-length-scale structures and dynamic variations of perovskite materials, but also for in situ monitoring of device functions and dynamics. The goal of this perspective is to present many capabilities and evoke emerging opportunities of synchrotron characterizations for providing decisive answers to the outstanding science problems in the perovskite field, pushing forward the technological development.

Strain and interactions at grain boundaries during solid-phase crystallization are known to play a significant role in the functional properties of polycrystalline materials. However, elucidating three-dimensional nanoscale grain morphology, kinetics, and strain under realistic conditions is challenging. Here, we image a single-grain growth during the amorphous-to-polycrystalline transition in technologically relevant transparent conductive oxide (TCO) film of In2O3:Zr with in-situ Bragg coherent X-ray diffraction imaging and transmission electron microscopy. We find that the Johnson-Mehl-Avrami-Kolmogorov theory, which describes the average kinetics of polycrystalline films growth, can be applied to the single grains as well. The quantitative analysis stems directly from imaging results. We elucidate the interface-controlled nature of the single-grain growth in thin films and reveal the surface strains which may be a driving force for anisotropic crystallization rates. Our results bring in-situ imaging with coherent X-rays towards understanding and controlling the crystallization processes of TCOs and other polycrystalline materials at the nanoscale.

Purpose The purpose of this paper is to explore the relationship between a chief executive officer (CEO)’s personal engagement in broader societal causes (CEO civic engagement) and firm’s social and environmental performance. Design/methodology/approach A theoretical framework was developed based on upper echelons and stakeholder theories to argue that CEOs’ professional background characteristics can be closely related to firm-level social and environmental performance. Hierarchical OLS analysis was conducted using data from 178 large, publicly traded large US firms between 2010 and 2013. Findings Overall, the findings suggest that firms led by CEOs with active civic engagement are more likely to support various philanthropic efforts. Additionally, the findings suggest that firms led by civic-minded CEOs are more likely to support an active corporate environmental engagement by investing significant resources in various environmental causes. Contrary to the authors’ predictions, the level of CEO civic engagement was not a significant predictor of firm level community engagement activities. Research limitations/implications The findings extend current scholarly work on executive determinants of corporate social performance by highlighting the important role of CEOs’ personal engagement beyond studying CEOs’ demographic characteristics. Specifically, the findings that the CEO-civic engagements lead to higher degrees of corporate philanthropy and environmental performance show that CEOs’ civic engagement can go beyond what is considered symbolic executive actions. Practical implications The findings suggest that firms that seek to foster social and environmental performance in a meaningful way should recruit and retain CEOs that have a personal commitment to and engagement in various social and environmental issues and causes. Originality/value By empirically examining the effect of CEO civic engagement on corporate philanthropy, community involvement and environmental performance, this paper seeks to contribute to the scholarly conversation on the effects of CEOs in shaping the firm’s social and environmental engagement and addressing external stakeholder concerns.

PurposeThe purpose of this paper is to provide a theoretical model for the relationship between quality management (QM) practices and the health and fitness industry through two competencies, including relational competence (RC) and technical competence (TC).Design/methodology/approachDrawing from the resource-based view and the relational competence theory, this paper seeks a further understanding of the conceptual link between QM practices and the health and fitness industry.FindingsThis paper proposes that RC and TC will positively mediate the relationship between QM practices and customers’ behavioral intentions to use the health and fitness service.Research limitations/implicationsThis paper provides an integrated perspective to the health and fitness industry. More specifically, this paper suggests that QM practices can be applicable to customers’ behavioral intentions to use the health and fitness service. This paper also provides a solid conceptual foundation through which managers in the health and fitness industry put more effort in developing the relationship with customers. An empirical investigation might be needed for future study.Practical implicationsThis paper suggests that managers and employees in the health and fitness industry need to provide a sustained and consistent effort into maintaining the interaction with customers. This paper also suggests that the use of QM practices can be related to customer perception (e.g. boosting behavioral intentions toward service providers) and can provide sustainable competitive advantage in the health and fitness industry.Originality/valueThis paper extends current understanding of QM practices and the health and fitness industry by providing a conceptual framework regarding how QM practices are related to the health and fitness industry through RC and TC.

Oxidation of magnetite (Fe3O4) has broad implications in geochemistry, environmental science and materials science. Spatially resolving strain fields and defect evolution during oxidation of magnetite provides further insight into its reaction mechanisms. Here we show that the morphology and internal strain distributions within individual nano-sized (~400 nm) magnetite crystals can be visualized using Bragg coherent diffractive imaging (BCDI). Oxidative dissolution in acidic solutions leads to increases in the magnitude and heterogeneity of internal strains. This heterogeneous strain likely results from lattice distortion caused by Fe(II) diffusion that leads to the observed domains of increasing compressive and tensile strains. In contrast, strain evolution is less pronounced during magnetite oxidation at elevated temperature in air. These results demonstrate that oxidative dissolution of magnetite can induce a rich array of strain and defect structures, which could be an important factor that contributes to the high reactivity observed on magnetite particles in aqueous environment., Oxidation of magnetite has broad implications in geochemistry and environmental science, but its reaction mechanisms are not fully understood yet. Here the authors use Bragg coherent diffractive imaging to show oxidative dissolution of magnetite inducing a rich array of strain and defect structures.

In the last two decades, Bragg Coherent X-ray Diffraction Imaging (BCDI) has become a powerful nanoscale characterization technique [1]. Its extreme sensitivity to lattice displacements enables to image three-dimensional morphology as well as internal deformation field distribution of nano- or micro-scaled various materials. In-situ and operando capabilities have been combined to BCDI to address scientific questions on materials under realistic conditions. Nowadays, in-situ/operando BCDI on electrochemistry successfully shows strain evolution and dislocation dynamics inside materials. In this talk, I will introduce current state-of-the-art of BCDI and the 34-ID-C beamline in the Advanced Photon Source which is dedicated to BCDI. This talk will also cover recent experimental results on in-situ/operando BCDI, for example, electrochemical dissolution/deposition [2] and battery materials during charging/discharging cycles [3,4]. [1] M. A. Pfeifer, et al., Nature 442, 63 (2006). [2] Y. Liu, et al., Nano Lett. 17, 1595 (2017). [3] A. Ulvestad, et al., Science 348, 1344 (2015). [4] A. Singer, et al., Nat. Energy 3, 641 (2018).

Strain is known to enhance the activity of the oxygen reduction reaction in catalytic platinum alloy nanoparticles, whose inactivity is the primary impediment to efficient fuel cells and metal-air batteries. Bragg coherent diffraction imaging (BCDI) was employed to reveal the strain evolution during the voltammetric cycling in Pt-Ni alloy nanoparticles composed of Pt2Ni3, Pt1Ni1, and Pt3Ni2. Analysis of the 3D strain images using a core-shell model shows that the strain as large as 5% is induced on Pt-rich shells due to Ni dissolution. The composition dependency of the strain on the shells is in excellent agreement with that of the catalytic activity. The present study demonstrates that BCDI enables quantitative determination of the strain on alloy nanoparticles during electrochemical reactions, which provides a means to exploit surface strain to design a wide range of electrocatalysts.

Non-equilibrium defects often dictate macroscopic functional properties of materials. In intercalation hosts, widely used in rechargeable batteries, high-dimensional defects largely define reversibility and kinetics. However, transient defects briefly appearing during ionic transport have been challenging to capture, limiting the understanding of their life cycle and impact. Here, we overcome this challenge and track operando the interaction and impact of metastable defects within NaxNi1-xMnyO2 intercalation hosts in a charging sodium-ion battery. Three-dimensional coherent X-ray imaging reveals transformation and self-healing of a metastable domain boundary, glissile dislocation loop, and stacking fault. A local strain gradient suggests a quantifiable difference in ion diffusion, coincident with the macroscopic change in diffusion coefficient. Analysis of the unexpected defect anisotropy highlights the importance of mesostructure, suggesting a possible control approach and disputing the rigidity of the framework layers. The shared nature of oxygen framework layers makes our results applicable to a wide range of intercalation materials.

Li- and Mn-rich (LMR) cathode materials that utilize both cation and anion redox can yield substantial increases in battery energy density

Bragg coherent diffraction imaging has the potential to provide significant insight into the structure-properties relationship for crystalline materials by imaging, with nanoscale resolution, three-dimensional strain fields within individual grains and nanoparticles. The capability of present-day synchrotrons to locate and measure a multiplicity of Bragg reflections from a single grain makes it possible to recover the full strain tensor with nanometer resolution. Recent methods for coupling reconstructions from several peaks to determine the strain tensor have been developed and applied to synthetic data, but have not been applied to experimental data. Here, using a coupled genetic reconstruction algorithm, we reconstruct an experimental data set and demonstrate improvements in the ability to resolve vector-valued displacement fields internal to the particle as compared to what is achieved with a noncoupled approach. The coupled approach developed in this work was also validated on simulated data sets. In both simulated and experimental data, reconstructions from our coupled Bragg peak algorithm show improvements over the noncoupled independent reconstruction method of $5%$ in terms of accuracy and $53%$ in terms of consistency.

Alloy catalysts such as Pt-M (M: other metal elements) have been extensively developed to improve the sluggish oxygen reduction reaction (ORR) that limits the efficiencies of fuel cells and metal-air batteries. Their catalytic activity is potentially enhanced by strain induced in a nearly pure Pt "shell" formed by dissolving the alloyed metal (M) from the surface. It is, therefore, of great importance to reveal the strain distribution on the Pt shell in situ so that we can exploit this mechanism to design new alloy catalysts. Yet, it has been challenging to analyze the strain on the shell because it inevitably requires a technique that can image the strain field of the nanoparticles with high spatial resolution. In this study,1 we successfully revealed the strain of the exemplary Pt-Ni alloy nanoparticles in detail from the 3D images obtained by using a novel synchrotron technique, “Bragg Coherent X-ray Diffraction Imaging” (BCDI), which can directly image minute atomic displacement field owing to the X-ray coherence. Pt-Ni nanoparticles with compositions of Pt2Ni3 (Ni rich), Pt1Ni1 (moderate Ni), and Pt3Ni2 (Ni poor) were observed by BCDI during cyclic voltammetry cycles, in which the less noble metal Ni electrochemically leached from the alloy. This cycling induced tensile strain inside particles in all the compositions, implying that the formation of a Pt shell on the surface strained the core of the particle because of the lattice mismatch between the Pt-Ni alloys and Pt. The strain in the shell was evaluated from a core-shell elastic model using the parameters obtained in the 3D images. A compressive circumferential strain in the shell was observed in all the compositions, and the Pt1Ni1 particle showed the largest compressive circumferential strain of 5%. Since the compressive strain is reported to facilitate the enhanced ORR,2 the compositional dependence of the strain magnitude observed in this study was in excellent agreement with the previous study performed with nm-size particles where Pt1Ni1 exhibits the highest activity among a wide range of compositions.3 A similar strain-activity relation was also inferred in a powder X-ray diffraction studies of core-shell Pt x Co1-x alloys,4 suggesting it is a widely applicable phenomenon. The present study demonstrated that the strain on alloy nanoparticles can be quantitatively determined by BCDI during electrochemical reactions, which enables us to exploit surface strain in designing a wide range of electrocatalysts. T. Kawaguchi et al., Nano Letters, 21, 5945–5951 (2021). H. Wang et al., Science, 354, 1031–1036 (2016). C. Wang et al., Advanced Functional Materials, 21, 147–152 (2011). D. Wang et al., Nature Materials, 12, 81–87 (2013).

Using operando Bragg coherent x-ray diffraction imaging, we visualised three-dimensionally a single twinned-gold nanocrystal during the CO oxidation reaction. We describe the defect dynamics process occurring under operating conditions and indicate the correlation between the nucleation of highly strained regions at the surface of the nanocrystal and its catalytic activity. Understanding the twinning deformation mechanism sheds light on the creation of active sites, and could well contribute to the understanding of the catalytic behaviour of other catalysts. With the start-up of 4th generation synchrotron sources, we anticipate that coherent hard x-ray diffraction imaging techniques will play a major role in imaging in situ chemical processes.

Nanometer scale 3D strain maps of metal nanocrystalline grains were imaged with x-ray Bragg coherent diffraction imaging while being heated to 713 ◦ C using a python-based, high-performance iterative phase reconstruction code called ‘Cohere.’

In this work, ferroelastic domain walls inside ${\mathrm{BaTiO}}_{3}$ (BTO) tetragonal nanocrystals are distinguished by Bragg peak position and studied with Bragg coherent x-ray diffraction imaging (BCDI). Convergence-related features of the BCDI method for strongly phased objects are reported. A ferroelastic domain wall inside a BTO crystal has been tracked and imaged across the tetragonal-cubic phase transition and proves to be reversible. The linear relationship of relative displacement between two twin domains with temperature is measured and shows a different slope for heating and cooling, while the tetragonality reproduces well over temperature changes in both directions. An edge dislocation is also observed and found to annihilate when heating the crystal close to the phase transition temperature.

Palladium absorbs large volumetric quantities of hydrogen at room temperature and ambient pressure, making the Pd-H system a promising candidate for hydrogen storage. Here, we use Bragg coherent diffraction imaging to map the strain associated with defects in three dimensions before and during the hydride phase transformation of an individual octahedral palladium nanoparticle, synthesized by using the seed-mediated approach. The displacement distribution imaging unveils the location of the seed nanoparticle in the final nanocrystal. By comparing our experimental results with a finite-element model, we verify that the seed nanoparticle causes a characteristic displacement distribution of the larger nanocrystal. During the hydrogen exposure, the hydride phase is predominantly formed on one tip of the octahedra, where there is a high number of lower coordinated Pd atoms. Our experimental and theoretical results provide an unambiguous method for future structure optimization of seed-mediated nanoparticles growth and in the design of palladium-based hydrogen storage systems.

The search for batteries with high energy density has highlighted lithium-rich manganese-based layered oxides due to their exceptionally high capacity. Although it is clear that both cationic and anionic redox are present in the charge compensation mechanism, the microstructural evolution of the Li2MnO3-like phase during anionic redox and its role in battery performance and structural stability are still not fully understood. Here, we systematically probe microstructural evolution using spatially resolved synchrotron X-ray measurements and reveal an underlying interaction between the Li2MnO3-like domains and bulk rhombohedral structure. Mn ion activation and a previously unobserved structural distortion are discovered at high voltages, and can be related to structural strain present in the Li2MnO3-like phase upon substantial lithium ion extraction. Moreover, we elucidate a correlation between this structural distortion and irreversible phase transitions by thermally perturbing delithiated samples. These insights highlight a pathway toward achieving high capacity cathode materials required for future commercial applications.

X-ray Bragg coherent diffraction imaging (BCDI) has been demonstrated as a powerful 3D microscopy approach for the investigation of sub-micrometre-scale crystalline particles. The approach is based on the measurement of a series of coherent Bragg diffraction intensity patterns that are numerically inverted to retrieve an image of the spatial distribution of the relative phase and amplitude of the Bragg structure factor of the diffracting sample. This 3D information, which is collected through an angular rotation of the sample, is necessarily obtained in a non-orthogonal frame in Fourier space that must be eventually reconciled. To deal with this, the approach currently favored by practitioners (detailed in Part I) is to perform the entire inversion in conjugate non-orthogonal real- and Fourier-space frames, and to transform the 3D sample image into an orthogonal frame as a post-processing step for result analysis. In this article, which is a direct follow-up of Part I, two different transformation strategies are demonstrated, which enable the entire inversion procedure of the measured data set to be performed in an orthogonal frame. The new approaches described here build mathematical and numerical frameworks that apply to the cases of evenly and non-evenly sampled data along the direction of sample rotation (i.e. the rocking curve). The value of these methods is that they rely on the experimental geometry, and they incorporate significantly more information about that geometry into the design of the phase-retrieval Fourier transformation than the strategy presented in Part I. Two important outcomes are (1) that the resulting sample image is correctly interpreted in a shear-free frame and (2) physically realistic constraints of BCDI phase retrieval that are difficult to implement with current methods are easily incorporated. Computing scripts are also given to aid readers in the implementation of the proposed formalisms.