Toward Operando Structural, Chemical, and Electrochemical Analyses of Solid-State Batteries Using Correlative Secondary Ion Mass Spectrometry Imaging.

The global transition from fossil fuels to green energy underpins the need for efficient and reliable energy storage systems. Advanced analysis and characterization of battery materials is not only important to understand fundamental battery properties but also crucial for their continued development. A deep understanding of these systems is often difficult to obtain through only pre- and/or post-mortem analyses, with the full complexity of a battery being hidden in its operational state. Thus, we have developed an operando methodology to analyze solid-state batteries (SSBs) structurally as well as chemically before, during, and after cycling. The approach is based on a specially designed sample holder, which enables a variety of electrochemical experiments. Since the entire workflow is performed within a single focused ion beam scanning electron microscope equipped with an in-house developed magnetic sector secondary ion mass spectrometer, we are able to pause the cycling at any time, perform analysis, and then continue cycling. Microstructural analysis is performed via secondary electron imaging, and the chemical mapping is performed using the secondary ion mass spectrometer. In this proof-of-concept study, we were able to identify dendrites in a short-circuited symmetric cell and to chemically map dendritic structures. While this methodology focuses on SSBs, the approach can directly be adapted to different battery systems and beyond. Our technique clearly has an advantage over many alternatives for battery analysis as no transfer of samples between instruments is needed and a correlation between the microstructure, chemical composition, and electrochemical performance is obtained directly.

Scanning Transmission Ion Microscopy Time-of-Flight Spectroscopy Using 20 keV Helium Ions.

Scanning transmission ion microscopy imaging was performed whilst using a delay-line detector to record the impact position and arrival time of transmitted ions or neutrals. The incident helium ion beam had an energy of 20 keV and the arrival time measurements were used to calculate the energy loss after transmission through the sample. The 5D dataset thus produced (2D position in the sample plane, 2D position in the detector plane, and energy) is analyzed by collection into energy spectra or images. It is demonstrated that ion energy loss maps can identify regions of identical materials in the sample plane. The behavior of the energy loss with respect to the scattering angle is calculated and these simulations agree with the experimentally measured results. This experiment demonstrates the capability of keV helium ions to be successfully used in energy loss imaging experiments. This is the first step in the development of keV scanning transmission ion microscopy energy loss techniques.

A FIB-SEM Based Correlative Methodology for X-Ray Nanotomography and Secondary Ion Mass Spectrometry: An Application Example in Lithium Batteries Research.

Correlative microscopy approaches are attracting considerable interest in several research fields such as materials and battery research. Recent developments regarding X-ray computer tomography have made this technique available in a compact module for scanning electron microscopes (SEMs). Nano-computed tomography (nanoCT) allows morphological analysis of samples in a nondestructive way and to generate 2D and 3D overviews. However, morphological analysis alone is not sufficient for advanced studies, and to draw conclusions beyond morphology, chemical analysis is needed. While conventional SEM-based chemical analysis techniques such as energy-dispersive X-ray spectroscopy (EDS) are adequate in many cases, they are not well suited for the analysis of trace elements and low-Z elements such as hydrogen or lithium. Furthermore, the large information depth in typical SEM-EDS imaging conditions limits the lateral resolution to micrometer length scales. In contrast, secondary ion mass spectrometry (SIMS) can perform elemental mapping with good surface sensitivity, nanoscale lateral resolution, and the possibility to analyze even low-Z elements and isotopes. In this study, we demonstrate the feasibility and compatibility of a novel FIB-SEM-based correlative nanoCT-SIMS imaging approach to correlate morphological and chemical data of the exact same sample volume, using a cathode material of a commercial lithium battery as an example.

Physiological and histopathological alterations in male Swiss mice after exposure to titanium dioxide (anatase) and zinc oxide nanoparticles and their binary mixture.

Existing studies have shown the systemic damage of titanium dioxide (TiO2) or zinc oxide (ZnO) nanoparticles (NPs), but there is little or no existing knowledge on the potential adverse toxic effects of the mixture of the two. In order to investigate the in vivo toxic effect of the mixture of TiO2 NPs and ZnO NPs, the acute toxicities of TiO2 NPs, ZnO NPs by themselves, and their mixture (1:1) were determined. The systemic toxicities of the individual NPs and mixture were evaluated in mice using hematological indices, hepatic, renal, and lipid profile parameters, and histopathology as endpoints. NPs were intraperitoneally administered at doses of 9.38, 18.75, 37.50, 75.00, and 150.00 mg/kg bw each. Individual NPs and their mixture were administered daily for 5 and 10 d, respectively. The LD50 of ZnO NPs was 299.9 mg/kg while TiO2 NPs by themselves or TiO2 NPs + ZnO NPs were indeterminate due to the absence of mortality of the male mice treated. TiO2 NPs, ZnO NPs by themselves and TiO2 NPs + ZnO NPs induced significant alterations in the hematological and biochemical parameters, with higher toxicity at 10 d. Histopathological lesions were observed in the liver, kidneys, spleen, heart, and brain of mice treated with the individual NPs and their mixture. TiO2 NPs + ZnO NPs were able to induce a higher systemic toxicity than TiO2 NPs or ZnO NPs individually. Our data suggest that more comprehensive risk assessments should be carried out on the mixture of NPs before utilization in consumer products.

Photoluminescence of ZnO/ZnMgO heterostructure nanobelts grown by MBE.

ZnO nanobelts may grow with their polar axis perpendicular to growth direction. Heterostructured nanobelts therefore contain hetero-interfaces along the polar axis of ZnO where polarisation mismatch may induce electron confinement. These interfaces run along the length of the nanobelts. Such heterostructure nanobelts are grown by molecular beam epitaxy and TEM images confirm the core-shell structure. The effects of shell-growth temperature on nano-heterostructures is investigated using photoluminescence and secondary ion mass spectrometry in a focussed ion-beam microscope with Ne+ as the primary ion beam. We perform low temperature photoluminescence on ensembles of such heterostructures and single nanostructures. We show how single nanobelts have photoluminescence spectra rich in features and attribute these to band misalignment at ZnO/ZnMgO interfaces embedded within nano-heterostructures.

Alteration of sperm parameters and reproductive hormones in Swiss mice via oxidative stress after co-exposure to titanium dioxide and zinc oxide nanoparticles.

In this study, Swiss male mice were intraperitoneally administered with titanium dioxide (TiO2 ) and zinc oxide (ZnO) nanoparticles (NPs) and their mixture (1:1) at doses between 9.38 and 75 mg/kg for 5 weeks to evaluate reproductive toxicity. Both NPs and their mixture significantly (p < .001) altered sperm motility, reduced sperm numbers and increased abnormalities, while their mixture induced more sperm abnormalities than either TiO2 NPs or ZnO NPs. Both NPs and their mixture significantly (p < .05) reduced the LH level, while ZnO NPs alone and their mixture (p < .001) increased the testosterone levels at tested doses. The testes of exposed mice showed pathological changes and altered histomorphometrics. TiO2 NPs and ZnO NPs individually induced a significant (p < .01) reduction in SOD and CAT activities, while the mixture significantly (p < .001) decreased CAT activity and increased SOD activity. TiO2 NPs alone at 9.38 mg/kg induced a significant (p < .001) reduction in the GSH level, while both NPs and their mixture increased the MDA level significantly (p < .05). The data showed that the mixture had a synergistic interaction to induce testicular damage. Overall, oxidative stress may be involved in the NP-mediated testicular damage observed.

Correlative Microscopy Combining Secondary Ion Mass Spectrometry and Electron Microscopy: Comparison of Intensity-Hue-Saturation and Laplacian Pyramid Methods for Image Fusion.

Correlative microscopy combining various imaging modalities offers powerful insights into obtaining a comprehensive understanding of physical, chemical, and biological phenomena. In this article, we investigate two approaches for image fusion in the context of combining the inherently lower-resolution chemical images obtained using secondary ion mass spectrometry (SIMS) with the high-resolution ultrastructural images obtained using electron microscopy (EM). We evaluate the image fusion methods with three different case studies selected to broadly represent the typical samples in life science research: (i) histology (unlabeled tissue), (ii) nanotoxicology, and (iii) metabolism (isotopically labeled tissue). We show that the intensity-hue-saturation fusion method often applied for EM-sharpening can result in serious image artifacts, especially in cases where different contrast mechanisms interplay. Here, we introduce and demonstrate Laplacian pyramid fusion as a powerful and more robust alternative method for image fusion. Both physical and technical aspects of correlative image overlay and image fusion specific to SIMS-based correlative microscopy are discussed in detail alongside the advantages, limitations, and the potential artifacts. Quantitative metrics to evaluate the results of image fusion are also discussed.

Elemental mapping of Neuromelanin organelles of human Substantia Nigra: correlative ultrastructural and chemical analysis by analytical transmission electron microscopy and nano-secondary ion mass spectrometry.

Neuromelanin (NM) is a compound which highly accumulates mainly in catecholamine neurons of the substantia nigra (SN), and is contained in organelles (NM-containing organelles) with lipid bodies and proteins. These neurons selectively degenerate in Parkinson's disease and NM can play either a protective or toxic role. NM-containing organelles of SN were investigated by Analytical Electron Microscopy (AEM) and Nano-Secondary Ion Mass Spectrometry (NanoSIMS) within human tissue sections with respect to ultrastructure and elemental composition. Within the NM-containing organelle, the single NM granules and lipid bodies had sizes of about 200-600 nm. Energy-Dispersive X-ray microanalysis spectra of the NM granules and lipid bodies were acquired with 100 nm beam diameter in AEM, NanoSIMS yielded elemental maps with a lateral resolution of about 150 nm. AEM yielded the quantitative elemental composition of NM granules and bound metals, e.g., iron with a mole fraction of about 0.15 atomic percent. Chemical analyses by AEM and NanoSIMS were consistent at the subcellular level so that nanoSIMS measurements have been quantitated. In NM granules of SN from healthy subjects, a significant amount of S, Fe, and Cu was found. In lipid bodies an amount of P consistent with the presence of phospholipids was measured. The improved detection limits of nanoSIMS offer new possibilities for chemical mapping, high-sensitivity trace element detection, and reduced acquisition times. Variations between individual NM granules can now be investigated effectively and quantitatively by NanoSIMS mapping Cu and Fe. This should yield new insight into the changes in chemical composition of NM pigments during healthy aging and disease. Neuromelanin-containing organelles of dopamine neurons in normal human substantia nigra were investigated by analytical electron mircoscopy and secondary ion mass spectroscopy (NanoSIMS) yielding the ultrastructure and elemental composition. In neuromelanin granules a significant amount of S, Fe and Cu was found. In lipid bodies an amount of P consistent with the presence of phospholipids was measured. The improved sensitivity of NanoSIMS shows differences in chemical composition between individual neuromelanin granules and allows to study chemical changes of neuromelanin organelles during aging and disease.

Effects of silver nanoparticles and ions on a co-culture model for the gastrointestinal epithelium.

BACKGROUND: The increased incorporation of silver nanoparticles (Ag NPs) into consumer products makes the characterization of potential risk for humans and other organisms essential. The oral route is an important uptake route for NPs, therefore the study of the gastrointestinal tract in respect to NP uptake and toxicity is very timely. The aim of the present study was to evaluate the effects of Ag NPs and ions on a Caco-2/TC7:HT29-MTX intestinal co-culture model with mucus secretion, which constitutes an important protective barrier to exogenous agents in vivo and may strongly influence particle uptake. METHODS: The presence of the mucus layer was confirmed with staining techniques (alcian blue and toluidine blue). Mono and co-cultures of Caco-2/TC7 and HT29-MTX cells were exposed to Ag NPs (Ag 20 and 200 nm) and AgNO3 and viability (alamar blue), ROS induction (DCFH-DA assay) and IL-8 release (ELISA) were measured. The particle agglomeration in the media was evaluated with DLS and the ion release with ultrafiltration and ICP-MS. The effects of the Ag NPs and AgNO3 on cells in co-culture were studied at a proteome level with two-dimensional difference in gel electrophoresis (2D-DIGE) followed by Matrix Assisted Laser Desorption Ionization - Time Of Flight/ Time Of Flight (MALDI-TOF/TOF) mass spectrometry (MS). Intracellular localization was assessed with NanoSIMS and TEM. RESULTS: The presence of mucus layer led to protection against ROS and decrease in IL-8 release. Both Ag 20 and 200 nm NPs were taken up by the cells and Ag NPs 20 nm were mainly localized in organelles with high sulfur content. A dose- and size-dependent increase in IL-8 release was observed with a lack of cytotoxicity and oxidative stress. Sixty one differentially abundant proteins were identified involved in cytoskeleton arrangement and cell cycle, oxidative stress, apoptosis, metabolism/detoxification and stress. CONCLUSIONS: The presence of mucus layer had an impact on modulating the induced toxicity of NPs. NP-specific effects were observed for uptake, pro-inflammatory response and changes at the proteome level. The low level of overlap between differentially abundant proteins observed in both Ag NPs and AgNO3 treated co-culture suggests size-dependent responses that cannot only be attributed to soluble Ag.

Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal-halide perovskites.

The technique of alloying FA+ with Cs+ is often used to promote structural stabilization of the desirable α-FAPbI3 phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality and enhance the stability have remained elusive. In this study, we advance that understanding by investigating the effect of cationic alloying in CsxFA1-xPbI3 perovskite thin-films and solar-cell devices. Selected-area electron diffraction patterns combined with microwave conductivity measurements reveal that fine Cs+ tuning (Cs0.15FA0.85PbI3) leads to a minimization of stacking faults and an increase in the photoconductivity of the perovskite films. Ultra-sensitive external quantum efficiency, kelvin-probe force microscopy and photoluminescence quantum yield measurements demonstrate similar Urbach energy values, comparable surface potential fluctuations and marginal impact on radiative emission yields, respectively, irrespective of Cs content. Despite this, these nanoscopic defects appear to have a detrimental impact on inter-grains'/domains' carrier transport, as evidenced by conductive-atomic force microscopy and corroborated by drastically reduced solar cell performance. Importantly, encapsulated Cs0.15FA0.85PbI3 devices show robust operational stability retaining 85% of the initial steady-state power conversion efficiency for 1400 hours under continuous 1 sun illumination at 35 °C, in open-circuit conditions. Our findings provide nuance to the famous defect tolerance of halide perovskites while providing solid evidence about the detrimental impact of these subtle structural imperfections on the long-term operational stability.

Interface passivation for 31.25%-efficient perovskite/silicon tandem solar cells.

Silicon solar cells are approaching their theoretical efficiency limit of 29%. This limitation can be exceeded with advanced device architectures, where two or more solar cells are stacked to improve the harvesting of solar energy. In this work, we devise a tandem device with a perovskite layer conformally coated on a silicon bottom cell featuring micrometric pyramids-the industry standard-to improve its photocurrent. Using an additive in the processing sequence, we regulate the perovskite crystallization process and alleviate recombination losses occurring at the perovskite top surface interfacing the electron-selective contact [buckminsterfullerene (C60)]. We demonstrate a device with an active area of 1.17 square centimeters, reaching a certified power conversion efficiency of 31.25%.

Thermal Recovery of the Electrochemically Degraded LiCoO2/Li7La3Zr2O12:Al,Ta Interface in an All-Solid-State Lithium Battery.

All-solid-state lithium batteries are promising candidates for next-generation energy storage systems. Their performance critically depends on the capacity and cycling stability of the cathodic layer. Cells with a garnet Li7La3Zr2O12 (LLZO) electrolyte can show high areal storage capacity. However, they commonly suffer from performance degradation during cycling. For fully inorganic cells based on LiCoO2 (LCO) as cathode active material and LLZO, the electrochemically induced interface amorphization has been identified as an origin of the performance degradation. This study shows that the amorphized interface can be recrystallized by thermal recovery (annealing) with nearly full restoration of the cell performance. The structural and chemical changes at the LCO/LLZO heterointerface associated with degradation and recovery were analyzed in detail and justified by thermodynamic modeling. Based on this comprehensive understanding, this work demonstrates a facile way to recover more than 80% of the initial storage capacity through a thermal recovery (annealing) step. The thermal recovery can be potentially used for cost-efficient recycling of ceramic all-solid-state batteries.

Quantitative nanoscale imaging using transmission He ion channelling contrast: Proof-of-concept and application to study isolated crystalline defects.

A newly developed microscope prototype, namely npSCOPE, consisting of a Gas Field Ion Source (GFIS) column and a position sensitive Delay-line Detector (DLD) was used to perform Scanning Transmission Ion Microscopy (STIM) using keV He+ ions. One experiment used 25 keV ions and a second experiment used 30 keV ions. STIM imaging of a 50 nm thick free-standing gold membrane exhibited excellent contrast due to ion channelling and revealed rich microstructural features including isolated nanoscale twin bands which matched well with the contrast in the conventional ion-induced Secondary Electron (SE) imaging mode. Transmission Kikuchi Diffraction (TKD) and Backscattered Electron (BSE) imaging were performed on the same areas to correlate and confirm the microstructural features observed in STIM. Monte Carlo simulations of the ion and electron trajectories were performed with parameters similar to the experimental conditions to derive insights related to beam broadening and its effect in the degradation of transmission image resolution. For the experimental conditions used, STIM imaging showed a lateral resolution close to30 nm. Dark twin bands in bright grains as well as bright twin bands in dark grains were observed in STIM. Some of the twin bands were invisible in STIM. For the specific experimental conditions used, the ion transmission efficiency across a particular twin band was found to decrease by a factor of 2.8. Surprisingly, some grains showed contrast reversal when the Field of View (FOV) was changed indicating the sensitivity of the channelling contrast to even small changes in illumination conditions. These observations are discussed using ion channelling conditions and crystallographic orientations of the grains and twin bands. This study demonstrates for the first time the potential of STIM imaging using keV He+ ions to quantitatively investigate channelling in nanoscale structures including isolated crystalline defects.

Scanning transmission imaging in the helium ion microscope using a microchannel plate with a delay line detector.

A detection system based on a microchannel plate with a delay line readout structure has been developed to perform scanning transmission ion microscopy (STIM) in the helium ion microscope (HIM). This system is an improvement over other existing approaches since it combines the information of the scanning beam position on the sample with the position (scattering angle) and time of the transmission events. Various imaging modes, such as bright field and dark field or the direct image of the transmitted signal, can be created by post-processing the collected STIM data. Furthermore, the detector has high spatial and temporal resolution, is sensitive to both ions and neutral particles over a wide energy range, and shows robustness against ion beam-induced damage. A special in-vacuum movable support gives the possibility of moving the detector vertically, placing the detector closer to the sample for the detection of high-angle scattering events, or moving it down to increase the angular resolution and distance for time-of-flight measurements. With this new system, we show composition-dependent contrast for amorphous materials and the contrast difference between small-angle and high-angle scattering signals. We also detect channeling-related contrast on polycrystalline silicon, thallium chloride nanocrystals, and single-crystalline silicon by comparing the signal transmitted at different directions for the same data set.

Stationary beam full-field transmission helium ion microscopy using sub-50 keV He+: Projected images and intensity patterns.

A dedicated transmission helium ion microscope (THIM) for sub-50 keV helium has been constructed to investigate ion scattering processes and contrast mechanisms, aiding the development of new imaging and analysis modalities. Unlike a commercial helium ion microscope (HIM), the in-house built instrument allows full flexibility in experimental configuration. Here, we report projection imaging and intensity patterns obtained from powder and bulk crystalline samples using stationary broad-beam as well as convergent-beam illumination conditions in THIM. The He+ ions formed unexpected spot patterns in the far field for MgO, BN and NaCl powder samples, but not for Au-coated MgO. The origin of the spot patterns in these samples was investigated. Surface diffraction of ions was excluded as a possible cause because the recorded scattering angles do not correspond to the predicted Bragg angles. Complementary secondary electron (SE) imaging in the HIM revealed that these samples charge significantly under He+ ion irradiation. The spot patterns obtained in the THIM experiments are explained as artefacts related to sample charging. The results presented here indicate that factors other than channeling, blocking and surface diffraction of ions have an impact on the final intensity distribution in the far field. Hence, the different processes contributing to the final intensities will need to be understood in order to decouple and study the relevant ion-beam scattering and deflection phenomena.

Genetic and systemic toxicity induced by silver and copper oxide nanoparticles, and their mixture in Clarias gariepinus (Burchell, 1822).

Unanticipated increase in the use of silver (Ag) and copper oxide (CuO) nanoparticles (NPs) due to their antimicrobial properties is eliciting environmental health concern because of their coexistence in the aquatic environment. Therefore, we investigated the genetic and systemic toxicity of the individual NPs and their mixture (1:1) using the piscine micronucleus (MN) assay, haematological, histopathological (skin, gills and liver) and hepatic oxidative stress analyses [malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)] in the African mud catfish, Clarias gariepinus. The fish were exposed to sublethal concentrations (6.25-100.00 mg/L) of each NP and their mixture for 28 days. Both NPs and their mixture induced significant (p < 0.05) increase in MN frequency and other nuclear abnormalities. There was significant decrease in haemoglobin concentration, red and white blood cell counts. Histopathological lesions observed include epidermal skin cells and gill lamellae hyperplasia and necrosis of hepatocytes. The levels of MDA, GSH and activities of SOD and CAT were impacted in C. gariepinus liver following the exposure to the NPs and their mixture. Interaction factor analysis of data indicates antagonistic genotoxicity and oxidative damage of the NPs mixture. These results suggest cytogenotoxic effects of Ag NPs, CuO NPs and their mixture via oxidative stress in Clarias gariepinus.

Evaluation of cytogenotoxicity and oxidative stress parameters in male Swiss mice co-exposed to titanium dioxide and zinc oxide nanoparticles.

A number of studies have investigated the adverse toxic effects of titanium dioxide (TiO2) nanoparticles (NPs) or zinc oxide (ZnO) NPs. Information on the potential genotoxic effects of the interactions of TiO2 NPs and ZnO NPs in vivo is lacking. Therefore, this study was designed to investigate the cytogenotoxicity of TiO2 NPs or ZnO NPs alone or their mixtures using the bone marrow micronucleus assay, and mechanism of damage through the evaluation of oxidative stress parameters in the liver and kidney tissues of Swiss mice. Intraperitoneal administration of doses between 9.38 and 150.00 mg/kg of TiO2 NPs or ZnO NPs or TiO2 NPs + ZnO NPs was performed for 5 and 10 days, respectively. TiO2 NPs alone induced a significant (P <  0.05) increase in micronucleated (Mn) polychromatic erythrocytes (PCEs) at the applied doses compared with the negative controls, with a significant difference between 5 and 10 days for TiO2 NPs alone and TiO2 NPs + ZnO NPs. Concurrently, TiO2 NPs alone for 5 days and TiO2 NPs and TiO2 NPs + ZnO NPs for 10 days significantly (P <  0.05) decreased the percentage PCE: normochromatic erythrocyte (NCE) indicating cytotoxicity; with a significant difference between the two periods. Significant (P <  0.001) changes in the activities of superoxide dismutase (SOD) and catalase (CAT), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were observed in the liver and kidney of mice exposed to TiO2 NPs or ZnO NPs alone or their mixtures. These results suggest that TiO2 NPs alone was genotoxic; TiO2 NPs and TiO2 NPs + ZnO NPs were noticeably cytotoxic while ZnO NPs was not cytogenotoxic. The individual NPs or their mixtures induced oxidative stress.