All-solid-state batteries (ASSBs) employing sulfide solid electrolytes and lithium metal anodes offer a promising pathway toward high energy density and enhanced safety. However, their practical deployment remains limited by strongly coupled electro-chemo-mechanical instabilities at both cathode and anode interfaces, which evolve across multiple length scales and remain insufficiently understood under realistic operating conditions. Here, we present a comprehensive multimodal operando characterization approach combining X-ray computed tomography (XCT), X-ray diffraction (XRD), and stack pressure monitoring to elucidate the dynamic degradation mechanisms in LiNi0.8Co0.1Mn0.1O2 (NCM811) | Li6PS5Cl (LPSC) | Li cells. By directly correlating particle-level morphological evolution with latticescale structural and strain dynamics, this methodology enables a unified, multiscale description of interfacial failure processes. Operando XCT and XRD jointly reveal reversible volume changes of ~6 % in NCM811 particles during (de-)lithiation. Spatially resolved operando XRD further uncovers pronounced heterogeneity in lithiation fronts and depth-dependent electrochemical activity across the cathode thickness. In parallel, a partial release of interfacial microstrain is identified at the NCM811|LPSC interface, associated with oxidative decomposition of LPSC solid electrolyte. At the LPSC|Li interface, operando XCT directly visualizes, at moderate current density (0.45 mA cm-2) but high areal capacity (4.17 mAh cm-2), crack initiation and propagation within the solid electrolyte, driven by the lithium plating-induced stress, followed by lithium infiltration, and progressive interfacial contact loss. These processes ultimately lead to mechanical disconnection and the emergence of short-circuiting at higher current densities. Notably, these mechanically induced degradation phenomena exhibit partial reversibility during lithium stripping. This multimodal operando framework provides critical insight into degradation pathways and establishes design principles for mechanically robust sulfide-based ASSBs.

Coccolithophores are unicellular marine phytoplankton that produce complex and intricately shaped mineralised scales called coccoliths. Coccoliths are produced in an intracellular vesicle where crystal nucleation occurs, from which several individual calcite units develop with anisotropic crystallographic facets, prompting studies into the cellular mechanisms which control crystal growth within the cell. Here, we characterise those morphological developments in 3D that occur during the formation of coccoliths by the species Gephyrocapsa huxleyi using cryo-ptychographic X-ray computed tomography. This technique is ideally suited to study coccolith mineral development, as intracellular structures can be imaged intact in their native state without needing to disrupt cells. Combined with additional imaging of developing coccoliths using cryo-transmission electron microscopy and scanning electron microscopy, we report the developmental stages involved in coccolith growth across the complete mineralisation period, while also showing that the constrained space created by individual crystal units growing in close confinement affects the final crystal morphology and overall mineral structure. These findings provide clarification on the mineralisation pathways that coccolithophores and other biomineralising organisms use to control the formation of highly functionalised crystalline structures, particularly relevant in the design of materials with tunable properties.

Dynamic processes such as crystallization, sintering and phase separation play pivotal roles in defining the structure and performance of engineered and natural materials. Yet, these phenomena are often challenging to study because they are transient, spatially heterogeneous, and span multiple length and time scales. Visualizing them in three dimensions under realistic conditions therefore requires imaging techniques capable of probing representative sample volumes with nanoscale resolution and minute-scale temporal resolution, sustained over extended observation times and across a wide range of environmental conditions, capabilities that current in situ methods rarely combine. Here, we present an integrated platform for in situ time- and temperature-resolved ptychographic X-ray nanotomography that meets these demands, and demonstrate its capability by tracking the crystallization of amorphous calcium carbonate from room temperature to 500°C. Quantitative tomograms are acquired at five-minute intervals, producing a 4D dataset that reveals multiple simultaneous crystallization pathways, and rare and transient events. Among these is the formation and recrystallization of a metastable polymorph, calcium carbonate hemihydrate, which has previously only been observed in additive-stabilized systems. We also demonstrate how volume defect evolution and structural rearrangements within individual crystals contribute to the mechanisms underlying Ostwald ripening. This platform offers a general method for in situ visualization of material transformations, providing insights into the processes that govern material structure and functionality.

Nanoparticles supported on the surface of porous carrier materials are the dominant form of heterogeneous catalysts today. Yet, they suffer from a common deactivation mechanism: the loss of active surface area under industrial use conditions. Deactivation often stems from the sintering of nanoparticles, a mass transport process whose mechanism and operating length scale are a topic of controversy. Investigating this process is challenging, requiring not only a behavioural characterisation of thousands of individual particles within the spatial confines of a hierarchically structured support but also a characterisation of their ensemble behaviour and local support interactions. Here, we introduce in-situ ptychographic X-ray computed nanotomography as a tool to facilitate this characterisation, allowing a local examination of catalysts in their use-geometry under operational-relevant conditions. Applied to methane oxidation over a palladium-on-silica supported catalyst, we reveal two concurrently operating deactivation drivers, short-range ripening and long-range particle migration, each with different temperature and atmosphere dependencies. The latter enables particles to traverse hundreds of nanometres through the support. These observations expand the current understanding of sintering behaviour in supported catalysts and demonstrate PXCT’s capability to resolve restructuring processes within complex porous materials.

Ptychographic X-ray computed tomography was used to image nanoporous gold samples, with and without metal oxide additives, following incremental ex situ annealing steps up to 750 °C. Studying the exact same sample volumes following sequential annealing steps allowed accurate 3D imaging of large meso- and macropore systems over extended sample volumes. Extraction of surface area, pore size distribution, and pore connectivity were demonstrated using a skeletonization method. These properties are relevant in the study of functional materials such as catalysts which rely on diffusion processes within the pores. Samples with metal oxide additives were found to be more resistant to thermal annealing and gold ligament coarsening up to 550 °C, while pure nanoporous gold showed a greater loss of specific surface area during the same treatment. An anomalous stabilisation effect was observed during measurements in ambient air, with minimal coarsening observed in sample regions previously exposed to X-rays, and extensive coarsening in neighbouring regions of the same sample which were not previously exposed to X-rays. Thermal annealing of duplicate samples under nitrogen flow eliminated this effect, suggesting the possible formation of a protective surface structure induced by X-ray irradiation of nanoporous gold in air. The same observations may not be visible to conventional bulk sorption or porosimetry methods, showing the benefits of X-ray tomography for quantitative spatially-resolved imaging of porous nanomaterials.

Solid state batteries (SSBs), utilizing a solid electrolyte (SE) and Li metal anode, promise long-range electric vehicles due to improvements in energy density and safety compared to current Li-ion technologies. Crucial to the practicality and optimization of SSBs is an understanding of the solid electrolyte interphase (SEI), a nanoscale and heterogeneous layer that forms between the Li anode and SE, governing ionic transport and degradation processes. However, in-depth characterisation of the SEI is challenging due to its thin, buried, and reactive nature. Here, we introduce a sample preparation method to isolate the Li-SEI-SE interface and use nanobeam electron diffraction microscopy to map the spatio-compositional structure of the interphase at room temperature. We showcase the capabilities of this approach by characterizing the SEI formed between two chemically and microstructurally distinct sulphide-based SEs and a Li metal anode.

Avoiding lithium dendrites at the lithium/ceramic electrolyte interface and as a result avoiding cell short-circuit when plating at practical current densities remains a significant challenge for all-solid-state batteries. Typically, values are limited to around 1 mA cm-2, even, for example, for garnets with a relative density of >99%. It is not obvious that simply densifying ceramic electrolytes will deliver high plating currents. Here we show that plating currents of 9 mA cm-2 can be achieved without dendrite formation, by densifying Argyrodite, Li6PS5Cl, to 99%. Changes in the microstructure of Li6PS5Cl on densification from 83 to 99% were determined by FIB-SEM tomography and used to calculate their effect on the critical current density (CCD). Not all changes in microstructure with densification act to increase CCD. While smaller pores and shorter cracks increase CCD, lower pore population and narrower cracks act to decrease CCD. Calculations show that the former changes dominate over the latter, predicating an overall increase in CCD, as observed experimentally.

Properties in crystalline and ordered materials tend to be anisotropic, with their orientation affecting the macroscopic behavior and functionality of materials. The ability to image the orientation of anisotropic material properties in three dimensions (3D) is fundamental for the understanding and functionality-driven development of novel materials. With the development of x-ray linear dichroic orientation tomography (XL-DOT), it is now possible to non-destructively map 3D orientation fields in micrometer-sized samples. In this work, we present the iterative, gradient-based reconstruction algorithm behind XL-DOT that can be used to map orientations based on linear dichroism in 3D. As linear dichroism can be exhibited by a broad spectrum of materials, XL-DOT can be used to map, for example, crystal orientations as well as ferroic alignment, such as ferroelectric and antiferromagnetic order. We demonstrate the robustness of this technique for orientation fields that exhibit smoothly varying and granular configurations, and subsequently identify and discuss optimal geometries for experimental data acquisition and optimal conditions for the reconstruction. We anticipate that this technique will be instrumental in enabling a deeper understanding of the relationship between material structures and their functionality, quantifying, for example, the orientation of charge distributions and magnetic anisotropies at the nanoscale in a wide variety of systems—from functional to energy materials.

Coccolithophores are abundant marine phytoplankton that produce biomineralized calcite scales, called coccoliths, which sequester substantial amounts of carbon and play a substantial role in biogeochemical cycles. However, mechanisms underlying the storage and transport of ions essential for calcification remain unresolved. We used ptychographic x-ray computed tomography under cryogenic conditions to visualize intracellular calcium-rich structures involved in the storage of calcium ions in the coccolithophore species Chrysotila carterae. During calcification, we observed a range of structures, from small electron-dense bodies within larger compartments to denser and distributed globular compartments, before returning to small bodies once scale formation is complete. Nanobeam-scanning x-ray fluorescence measurements further revealed that these electron-dense bodies are rich in phosphorus and calcium (molar ratio of ~4:1). The dynamic nature of structures suggests that these bodies are part of the required cellular calcium ion transport pathways, a fundamental process critical for understanding the response of coccolithophores to climate change.

Advances in X-ray nanoprobe beamlines at synchrotrons across the world present exciting opportunities for rich multimodal imaging of biomineral structures and their formation processes. The combination of techniques provides a sensitive probe of both chemistry and structure, making X-ray nanoprobes an important tool for investigating crystallite growth and orientations, interfaces, and assembly of building blocks into hierarchical structures. A discussion of these capabilities is presented with reference to recent examples using a range of nanoprobe imaging techniques for investigating enamel structure, as well as coccolith properties. Key opportunities for the use of X-ray nanoprobes lie in exploiting the penetrating power and coherence properties of synchrotron X-rays in order to image in situ processes or apply coherent diffractive imaging techniques to obtain higher resolutions. To this end initial results demonstrating the observation of calcium phosphate mineralisation, in a liquid environment, using nano-X-ray fluorescence mapping are presented, and the role of X-ray dose and beam induced effects is considered. Finally novel results from tomographic ptychography imaging of Mytilus edulis mussel shell calcite prisms are discussed, where the segmentation of the phase density into organic and mineral content gives insights into the mechanisms underlying mineral prism formation and the role of the organic matrix in biomineralisation.

Tomographic imaging of time-evolving samples is a challenging yet important task for various research fields. At the nanoscale, current approaches face limitations of measurement speed or resolution due to lengthy acquisitions. We developed a dynamic nanotomography technique based on sparse dynamic imaging and 4D tomography modeling. We demonstrated the technique, using ptychographic x-ray computed tomography as its imaging modality, on resolving the in situ hydration process of polymer electrolyte fuel cell (PEFC) catalyst. The technique provides a 40-time increase in temporal resolution compared to conventional approaches, yielding 28 nm half-period spatial and 12 min temporal resolution. The results allow a quantitative characterization of the water intake process inside PEFC catalysts with nanoscale resolution, which is crucial for understanding their electrochemical mechanisms and optimizing their performance. Our technique enables high-speed operando nanotomography studies and paves the way for wider application of dynamic tomography at the nanoscale.

The aviation industry’s shift toward electrification demands greater energy density and enhanced cell safety compared to commercial lithium-ion batteries. Transition metal fluoride cathodes can store multiple lithium ions per metal center through a conversion reaction mechanism, resulting in a 3-fold increase in capacity compared to intercalation compounds. Additionally, fluoride cathodes exhibit remarkable thermal stability due to the ionic nature of the metal-fluoride bond. However, their practical implementation faces challenges due to their limited electronic and ionic conductivity. In this study, we conducted a comprehensive investigation of FeF2-Li metal cells in a lithium bis(fluorosulfonyl)imide N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ionic liquid electrolyte. We explored the effects of FeF2 particle size, the distribution of conductive additives within the electrode, and the influence of the bis(fluorosulfonyl)imide anion on electrochemical behavior and its evolution throughout cycling. Our findings suggest that the rate requirements for electric aviation could be met at 80°C.

Transport and thermodynamic properties are integral parameters to understand, model, and optimize state-of-the-art and next-generation battery electrolytes. The accurate measurement of these properties is experimentally challenging as well as time- and resource-intensive, and consequently, reports are scarce. Their dependence on temperature is explored even less and is commonly limited to a few temperature points. Recently, we introduced an operando Raman gradient analysis (ORGA) tool to extract transport and thermodynamic properties. Here, we expand the capabilities of ORGA by incorporating a temperature-sensitive external reference into the design. With this enhancement, we are able to visualize the local concentration of any Raman-active species in the electrolyte and detect lithium filament nucleation. We demonstrate and validate this new functionality of ORGA via an examination of lithium bis(fluorosulfonyl)imide (LiFSI) in tetraethylene glycol dimethyl ether (G4) as a function of temperature. All transport properties and activation energies are reported, and the effect of temperature is discussed.

In situ X-ray photoelectron spectroscopy (XPS) techniques have proven to be powerful tools for the characterisation of the solid electrolyte interphase (SEI) formed between the anode and solid electrolyte (SE) in solid-state batteries. XPS offers access to time and operational condition-resolved information on the SEI’s chemical composition in the absence of destructive sample preparation. Here we present a Virtual Electrode Plating XPS (VEP-XPS) investigation of the composition and stability of the SEI formed between lithium metal and two different solid electrolytes: Li10GeP2S12 (LGPS)andLi1.5Al0.5Ge1.5(PO4)3 (LAGP). LAGP shows slower SEI formation kinetics, as proven by the emergence of a metallic lithium signal, while LGPS exhibits rapid SEI growth that prevents metallic lithium from plating. We attribute these observations to the SEI composition, distribution and physical properties of secondary de- composition products and in particular to the mixed ion-electron conductive Li3P which can be observed in LGPS and not in LAGP

Understanding and characterizing the transport and thermodynamic properties of electrolytes are critical for optimizing battery performance. In this study, we employ operando Raman gradient analysis (ORGA) to characterize the concentration-dependent diffusion coefficient, transference number, ionic conductivity, and thermodynamic factor of potassium bis(fluorosulfonyl)imide (KFSI) in triethyl phosphate (TEP), an ideal model system and one of the most promising K-ion battery electrolytes. ORGA demonstrates results consistent with conventional state-of-the-art methods while proving to be significantly more electrolyte- and time-efficient. Additionally, we probe, for the first time, the concentration-dependent transport and thermodynamic properties of KFSI-TEP, providing key parameters for K-ion battery modeling.

In situ X-ray photoelectron spectroscopy (XPS) techniques have proven to be powerful tools for the characterisation of the solid electrolyte interphase (SEI) formed between the anode and solid electrolyte (SE) in solid-state batteries. XPS offers access to time and operational condition-resolved information on the SEI's chemical composition in the absence of destructive sample preparation. Here we present a Virtual Electrode Plating XPS (VEP-XPS) investigation of the composition and stability of the SEI formed between lithium metal and two different solid electrolytes: Li10GeP2S12 (LGPS) and Li1.5Al0.5Ge1.5(PO4)3 (LAGP). LAGP shows slower SEI formation kinetics, as proven by the emergence of a metallic lithium signal, while LGPS exhibits rapid SEI growth that prevents metallic lithium from plating. We attribute these observations to the SEI composition, distribution and physical properties of secondary decomposition products and in particular to the mixed ion-electron conductive Li3P which can be observed in LGPS and not in LAGP.

The functionality of materials is determined by their composition and microstructure, that is, the distribution and orientation of crystalline grains, grain boundaries and the defects within them. The characterisation of the material's microstructure is therefore critical for materials applications such as catalysis, energy storage and buildings. Until now, characterization techniques that map the distribution of grains, their orientation, and the presence of defects have either been limited to surface investigations, to spatial resolutions of a few hundred nanometres, or to systems of thickness around one hundred nanometres, thus requiring destructive sample preparation for measurements and preventing the study of system-representative volumes or the investigation of materials under operational conditions. Here, we present X-ray linear dichroic orientation tomography, a quantitative, non-invasive technique that allows for an intra- and inter-granular characterisation of extended polycrystalline and amorphous materials in three dimensions (3D). We present the detailed characterisation of a polycrystalline sample of vanadium pentoxide (V2O5), a key catalyst in the production of sulfuric acid. In addition to determining the nanoscale composition, we map the crystal orientation throughout the polycrystalline sample with 73 nm spatial resolution. We identify grains, as well as twist, tilt, and twin grain boundaries. We further observe the creation and annihilation of topological defects promoted by the presence of volume crystallographic defects in 3D. Our method's non-destructive and spectroscopic nature opens the door to in-operando combined chemical and microstructural investigations of functional materials, including energy and mechanical materials in existing industries, as well as quantum materials for future technologies.

The acquisition speed and spatial resolution of X-ray nanotomography have continuously improved over the last decades. Coherent diffraction-based techniques breach the 10 nm resolution barrier frequently and thus pose stringent demands on sample positioning accuracy and stability. At the same time there is an increasing desire to accommodate in situ or operando measurements. Here, an environmental control system for X-ray nanotomography is introduced to regulate the temperature of a sample from room temperature up to 850°C in a controlled atmospheric composition. The system allows for a 360° sample rotation, permitting tomographic studies in situ or operando free of missing wedge constraints. The system is implemented and available at the flOMNI microscope at the Swiss Light Source. In addition to the environmental control system itself, the related modifications of flOMNI are described. Tomographic measurements of a nanoporous gold sample at 50°C and 600°C at a resolution of sub-20 nm demonstrate the performance of the device.

Preparation conditions have a vital effect on the structure of alumina-supported hydrodesulfurization (HDS) catalysts. To explore this effect, we prepared two NiMoS/Al2O3 catalyst samples with the same target composition using different chemical sources and characterizing the oxidic NiMo precursors and sulfided and spent catalysts to understand the influence of catalyst structure on performance. The sample prepared from ammonium heptamolybdate and nickel nitrate (sample A) contains Mo in the oxidic precursor predominantly in tetrahedral coordination in the form of crystalline domains, which show low reducibility and strong metal-support interactions. This property influences the sulfidation process such that the sulfidation processes of Ni and Mo occur tendentially separately with a decreased efficiency to form active Ni-Mo-S particles. Moreover, inactive unsupported MoS2 particles or isolated NiS x species are formed, which are either washed off during catalytic reaction or aggregated to larger particles as seen in scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDX). The oxidic precursor of the sample synthesized using nickel carbonate and molybdenum trioxide as metal sources (sample B), however, contains Mo in octahedral coordination and shows higher reducibility of the metal species as well as weaker metal-support interactions than that of sample A; these properties allow an efficient sulfidation of Mo and Ni such that formation of active Ni-Mo-S particles is the main product. Ptychographic X-ray computed tomography (PXCT) and STEM and EDX measurements show that the structure formed during sulfidation is stable under operation conditions. The structural differences explain the HDS activity difference between these two samples and explain why sample B is much active than sample A.