Mapping internal temperatures during high-rate battery applications.

Electric vehicles demand high charge and discharge rates creating potentially dangerous temperature rises. Lithium-ion cells are sealed during their manufacture, making internal temperatures challenging to probe1. Tracking current collector expansion using X-ray diffraction (XRD) permits non-destructive internal temperature measurements2; however, cylindrical cells are known to experience complex internal strain3,4. Here, we characterize the state of charge, mechanical strain and temperature within lithium-ion 18650 cells operated at high rates (above 3C) by means of two advanced synchrotron XRD methods: first, as entire cross-sectional temperature maps during open-circuit cooling and second, single-point temperatures during charge-discharge cycling. We observed that a 20-minute discharge on an energy-optimized cell (3.5 Ah) resulted in internal temperatures above 70 °C, whereas a faster 12-minute discharge on a power-optimized cell (1.5 Ah) resulted in substantially lower temperatures (below 50 °C). However, when comparing the two cells under the same electrical current, the peak temperatures were similar, for example, a 6 A discharge resulted in 40 °C peak temperatures for both cell types. We observe that the operando temperature rise is due to heat accumulation, strongly influenced by the charging protocol, for example, constant current and/or constant voltage; mechanisms that worsen with cycling because degradation increases the cell resistance. Design mitigations for temperature-related battery issues should now be explored using this new methodology to provide opportunities for improved thermal management during high-rate electric vehicle applications.

A novel fuel cell design foroperandoenergy-dispersive x-ray absorption measurements.

A polymer electrolyte fuel cell has been designed to allowoperandox-ray absorption spectroscopy (XAS) measurements of catalysts. The cell has been developed to operate under standard fuel cell conditions, with elevated temperatures and humidification of the gas-phase reactants, both of which greatly impact the catalyst utilisation. X-ray windows in the endplates of the cell facilitate collection of XAS spectra during fuel cell operation while maintaining good compression in the area of measurement. Results of polarisation curves and cyclic voltammograms showed that theoperandocell performs well as a fuel cell, while also providing XAS data of suitable quality for robust XANES analysis. The cell has produced comparable XAS results when performing a cyclic voltammogram to an establishedin situcell when measuring the Pt LIII edge. Similar trends of Pt oxidation, and reduction of the formed Pt oxide, have been presented with a time resolution of 5 s for each spectrum, paving the way for time-resolved spectral measurements of fuel cell catalysts in a fully-operating fuel cell.

Data for an Advanced Microstructural and Electrochemical Datasheet on 18650 Li-ion Batteries with Nickel-Rich NMC811 Cathodes and Graphite-Silicon Anodes.

The data presented here were collected from a commercial LG Chem cylindrical INR18650 MJ1 lithium-ion (Li-ion) battery (approximate nominal specifications: 3.5 Ah, 3.6 V, 12.2 Wh). Electrochemical and microstructural information is presented, the latter collected across several length scales using X-ray computed tomography (CT): from cell to particle. One cell-level tomogram, four assembly-level and two electrode/particle-level 3D datasets are available; all data was collected in the pristine state. The electrochemical data consists of the full current and voltage charge-discharge curves for 400 operational cycles. All data has been made freely available via a repository [10.5522/04/c.4994651] in order to aid in the development of improved computational models for commercially-relevant Li-ion battery materials.

Data on the theoretical X-Ray attenuation and transmissions for lithium-ion battery cathodes.

This article reports the data required for planning attenuation-based X-ray characterisation e.g. X-ray computed tomography (CT), of lithium-ion (Li-ion) battery cathodes. The data reported here is to accompany a co-submitted manuscript (10.1016/j.matdes.2020.108585 [1]) which compares two well-known X-ray attenuation data sources: Henke et al. and Hubbell et al., and applies methodology reported by Reiter et al. to extend this data towards the practical characterisation of prominent cathode materials. This data may be used to extend beyond the analysis reported in the accompanying manuscript, and may aid in the applications for other materials, not limited to Li-ion batteries.

Packed bed compression visualisation and flow simulation using an erosion-dilation approach.

X-ray computed tomography has been demonstrated to be capable of imaging 1 mL (5 mm diameter, 50 mm height) chromatography packed beds under compression, visualising the 3D structure and measuring changes to geometry of the packing. 1 mL pre-packed columns did not exhibit any structural changes at vendor specified flow rate limits, however cellulose beds did compress at higher flow rates that were imaged before, during and after flow. This was used to visualise and quantitate changes to porosity, tortuosity and permeability based on simulation of flow through the packed bed structure using the imaging data. When using a high flow rate it was found that a decrease in porosity could be measured during compression before reverting after flow had ceased, with corresponding changes to tortuosity and permeability also occurring. X-ray CT imaging of packed beds and individual beads exposed to foulant-rich process streams resulted in considerable image quality loss, associated with residual biological material. In order to address this, digital processing using an erosion-dilation method was applied at bead and bed scales to computationally alter the porosity by adding or removing material from the existing surface to calculate the impact upon tortuosity factor. The eroded and dilated bead volumes of agarose, cellulose and ceramic materials were used to simulate diffusivity whilst mimicking internal bead pore constriction and blocking mechanisms.

Three dimensional characterisation of chromatography bead internal structure using X-ray computed tomography and focused ion beam microscopy.

X-ray computed tomography (CT) and focused ion beam (FIB) microscopy were used to generate three dimensional representations of chromatography beads for quantitative analysis of important physical characteristics including tortuosity factor. Critical-point dried agarose, cellulose and ceramic beads were examined using both methods before digital reconstruction and geometry based analysis for comparison between techniques and materials examined. X-ray 'nano' CT attained a pixel size of 63 nm and 32 nm for respective large field of view and high resolution modes. FIB improved upon this to a 15 nm pixel size for the more rigid ceramic beads but required compromises for the softer agarose and cellulose materials, especially during physical sectioning that was not required for X-ray CT. Digital processing of raw slices was performed using software to produce 3D representations of bead geometry. Porosity, tortuosity factor, surface area to volume ratio and pore diameter were evaluated for each technique and material, with overall averaged simulated tortuosity factors of 1.36, 1.37 and 1.51 for agarose, cellulose and ceramic volumes respectively. Results were compared to existing literature values acquired using established imaging and non-imaging techniques to demonstrate the capability of tomographic approaches used here.

Algorithmic structural segmentation of defective particle systems: a lithium-ion battery study.

We describe a segmentation algorithm that is able to identify defects (cracks, holes and breakages) in particle systems. This information is used to segment image data into individual particles, where each particle and its defects are identified accordingly. We apply the method to particle systems that appear in Li-ion battery electrodes. First, the algorithm is validated using simulated data from a stochastic 3D microstructure model, where we have full information about defects. This allows us to quantify the accuracy of the segmentation result. Then we show that the algorithm can successfully be applied to tomographic image data from real battery anodes and cathodes, which are composed of particle systems with very different morpohological properties. Finally, we show how the results of the segmentation algorithm can be used for structural analysis.

Investigating the evolving microstructure of lithium metal electrodes in 3D using X-ray computed tomography.

The growth of electrodeposited lithium microstructures on metallic lithium electrodes has prevented their use in rechargeable lithium batteries due to early performance degradation and safety implications. Understanding the evolution of lithium microstructures during battery operation is crucial for the development of an effective and safe rechargeable lithium-metal battery. This study employs both synchrotron and laboratory X-ray computed tomography to investigate the morphological evolution of the surface of metallic lithium electrodes during a single cell discharge and over numerous cycles, respectively. The formation of surface pits and the growth of mossy lithium deposits through the separator layer are characterised in three-dimensions. This has provided insight into the microstructural evolution of lithium-metal electrodes during rechargeable battery operation, and further understanding of the importance of separator architecture in mitigating lithium dendrite growth.

X-ray Phase-Contrast Radiography and Tomography with a Multiaperture Analyzer.

We present a multiaperture analyzer setup for performing x-ray phase contrast imaging in planar and three-dimensional modalities. The method is based on strongly structuring the x-ray beam with an amplitude modulator, before it reaches the sample, and on a multiaperture analyzing element before detection. A multislice representation of the sample is used to establish a quantitative relation between projection images and the corresponding three-dimensional distributions, leading to successful tomographic reconstruction. Sample absorption, phase, and scattering are retrieved from the measurement of five intensity projections. The method is tested on custom-built phantoms with synchrotron radiation: sample absorption and phase can be reliably retrieved also in combination with strong scatterers, simultaneously attaining high sensitivity and dynamic range.

Laser-preparation of geometrically optimised samples for X-ray nano-CT.

A robust and versatile sample preparation technique for the fabrication of cylindrical pillars for imaging by X-ray nano-computed tomography (nano-CT) is presented. The procedure employs simple, cost-effective laser micro-machining coupled with focused-ion beam (FIB) milling, when required, to yield mechanically robust samples at the micrometre length-scale to match the field-of-view (FOV) for nano-CT imaging. A variety of energy and geological materials are exhibited as case studies, demonstrating the procedure can be applied to a variety of materials to provide geometrically optimised samples whose size and shape are tailored to the attenuation coefficients of the constituent phases. The procedure can be implemented for the bespoke preparation of pillars for both lab- and synchrotron-based X-ray nano-CT investigations of a wide range of samples.

Assessment of the equivalence of a generic to a branded femoral stem.

AIMS: The aim of this study was to compare the design of the generic OptiStem XTR femoral stem with the established Exeter femoral stem. MATERIALS AND METHODS: We obtained five boxed, as manufactured, implants of both designs at random (ten in total). Two examiners were blinded to the implant design and independently measured the mass, volume, trunnion surface topography, trunnion roughness, trunnion cone angle, Caput-Collum-Diaphyseal (CCD) angle, femoral offset, stem length, neck length, and the width and roughness of the polished stem shaft using peer-reviewed methods. We then compared the stems using these parameters. RESULTS: We found that the OptiStems were lighter (p < 0.001), had a rougher trunnion surface (p < 0.001) with a greater spacing and depth of the machined threads (p < 0.001), had greater trunnion cone angles (p = 0.007), and a smaller radius at the top of the trunnion (p = 0.007). There was no difference in stem volume (p = 0.643), CCD angle (p = 0.788), offset (p = 0.993), neck length (p = 0.344), stem length (p = 0.808), shaft width (p = 0.058 to 0.720) or roughness of the polished surface (p = 0.536). CONCLUSION: This preliminary investigation found that whilst there were similarities between the two designs, the generic OptiStem is different to the branded Exeter design. Cite this article: Bone Joint J 2017;99-B:310-16.

X-ray computed tomography of packed bed chromatography columns for three dimensional imaging and analysis.

Physical characteristics critical to chromatography including geometric porosity and tortuosity within the packed column were analysed based upon three dimensional reconstructions of bed structure in-situ. Image acquisition was performed using two X-ray computed tomography systems, with optimisation of column imaging performed for each sample in order to produce three dimensional representations of packed beds at 3µm resolution. Two bead materials, cellulose and ceramic, were studied using the same optimisation strategy but resulted in differing parameters required for X-ray computed tomography image generation. After image reconstruction and processing into a digital three dimensional format, physical characteristics of each packed bed were analysed, including geometric porosity, tortuosity, surface area to volume ratio as well as inter-bead void diameters. Average porosities of 34.0% and 36.1% were found for ceramic and cellulose samples and average tortuosity readings at 1.40 and 1.79 respectively, with greater porosity and reduced tortuosity overall values at the centre compared to the column edges found in each case. X-ray computed tomography is demonstrated to be a viable method for three dimensional imaging of packed bed chromatography systems, enabling geometry based analysis of column axial and radial heterogeneity that is not feasible using traditional techniques for packing quality which provide an ensemble measure.

Real time chemical imaging of a working catalytic membrane reactor during oxidative coupling of methane.

We report the results from an operando XRD-CT study of a working catalytic membrane reactor for the oxidative coupling of methane. These results reveal the importance of the evolving solid state chemistry during catalytic reaction, particularly the chemical interaction between the catalyst and the oxygen transport membrane.

Comparison of residual oil cluster size distribution, morphology and saturation in oil-wet and water-wet sandstone.

We imaged an oil-wet sandstone at residual oil saturation (S(or)) conditions using X-ray micro-tomography with a nominal voxel size of (9 µm)(3) and monochromatic light from a synchrotron source. The sandstone was rendered oil-wet by ageing with a North Sea crude oil to represent a typical wettability encountered in hydrocarbon reservoirs. We measured a significantly lower S(or) for the oil-wet core (18.8%) than for an analogue water-wet core (35%). We analysed the residual oil cluster size distribution and find consistency with percolation theory that predicts a power-law cluster size distribution. We measure a power-law exponent τ=2.12 for the oil-wet core which is higher than τ for the water-wet system (τ=2.05), indicating fewer large clusters in the oil-wet case. The clusters are rough and sheet-like consistent with connectivity established through layers in the pore space and occupancy of the smaller pores; in contrast the clusters for water-wet media occupy the centres of the larger pores. These results imply less trapping of oil, but with a greater surface area for dissolution. In carbon storage applications, this suggests that in CO(2)-wet systems, capillary trapping is less significant, but that there is a large surface area for dissolution and reaction.

Twenty-four-hour insulin secretion rates, circulating concentrations of fuel substrates and gut incretin hormones in healthy offspring of Type II (non-insulin-dependent) diabetic parents: evidence of several aberrations.

AIMS/HYPOTHESIS: Insulin resistance is a common feature in relatives of patients with Type II (non-insulin-dependent) diabetes mellitus and abnormalities in beta-cell function can also exist. Insight into non-fasting carbohydrate metabolism in these potentially prediabetic subjects relies almost exclusively on studies in which glucose is infused or ingested or both. We aimed to characterize insulin secretion and aspects of hormonal and metabolic patterns in relatives using a physiological approach. METHODS: We examined profiles of insulin, C peptide, proinsulin, gut incretin hormones and fuel substrates in 26 glucose tolerant but insulin resistant (clamp) relatives and 17 control subjects during a 24-hour period including three meals. RESULTS: During the day plasma glucose was slightly raised in relatives (p < 0.05). Overall insulin secretion calculated on the basis of C peptide kinetics were increased in relatives (p < 0.0005) whereas incremental insulin secretion after all three meals were similar. Peak incremental insulin secretion tended, however, to be reduced in relatives (p < 0.10). Despite considerably increased insulin concentrations in relatives (70 %, p < 0.001), serum NEFA did not differ. Postprandial proinsulin concentrations (p < 0.05), but not proinsulin:insulin ratios, were increased in relatives. After meals concentrations of glucose-dependent-insulinotropic polypeptide (p < 0.05) were increased in relatives. Glucagon-like peptide-1 concentrations were similar. CONCLUSION/INTERPRETATION: Several hormonal and metabolic aberrations are present in healthy relatives of Type II diabetic patients during conditions that simulate daily living. Increased concentrations of glucose-dependent-insulinotropic polypeptide could indicate a beta-cell receptor defect for glucose-dependent-insulinotropic polypeptide in the prediabetic stage of Type II diabetes. Incremental insulin secretion after mixed meals appear normal in relatives, although a trend towards diminished peak values possibly signifies early beta-cell dysfunction. [Diabetologia (1999) 42: 1314-1323]

Hydroxyproline excretion is increased in diabetes mellitus and related to the presence of microalbuminuria.

Increased fracture frequency and low bone mass have each been reported in patients with diabetes. To see if these were related to increased bone resorption we have measured the urinary excretion of hydroxyproline in 73 patients with Type 1 (insulin-dependent) diabetes, 67 patients with Type 2 (non-insulin-dependent) diabetes, and 75 control subjects. Hydroxyproline excretion was increased in both types of diabetes: Type 1: 21 (10-36) (median (IQR) mumol mmol creatinine-1; Type 2: 25 (13-43) mumol mmol creatinine-1; control: 10 (6-22) mumol mmol creatinine-1 (p < 0.0001 and < 0.0002, respectively). Hydroxyproline excretion was not related to age, duration of diabetes or blood glucose control. Neither was it different in patients with or without retinopathy, neuropathy and macrovascular disease. However it was higher in patients with microalbuminuria at 35 (20-53) mumol mmol creatinine-1 than in those with normal protein excretion (25(13-37) mumol mmol creatinine-1 p = 0.03) or those with established proteinuria (18(8-26) mumol mmol creatinine-1 p = 0.001). We conclude that there is evidence of increased bone resorption in diabetes and that this is related to alterations in renal function.

Micral-test strips evaluated for screening for albuminuria.

We have evaluated Micral-Test, an immunochemical strip test specific for albumin, as a screening tool for slight ("micro") albuminuria. First morning urine samples containing albumin concentrations (by radioimmunoassay) of 0.4-440 mg/L were collected from 112 diabetic patients. The Micral-Test result for each sample was assessed by one observer. All 34 samples having albumin concentrations greater than or equal to 20 mg/L and 71 of 78 samples less than 20 mg/L were correctly identified, giving 100% sensitivity and 91% specificity. Six samples were measured 10 times by one observer: three samples were read consistently; one, albumin concentration 86 mg/L, was read as 50 and 100 mg/L; and two, albumin concentrations 32 and 38 mg/L, were read as 20 and 50 mg/L, respectively. Contact with urine for 2 s rather than the recommended 5 s resulted in an underestimation of the albumin concentration in 13 of 35 samples (Z = -3.18, P = 0.001), as did taking readings earlier than the recommended 5 min (Z = -3.92, P less than 0.001). Six observers independently performed Micral-Test measurements on 10 samples. Eight samples were correctly classified as greater than or equal to 20 or less than 20 mg/L by all observers, but two (albumin concentrations 25 and 18 mg/L) were misclassified by at least one observer. The Micral-Test is a sensitive and specific screening tool, but is semiquantitative and critically time dependent.

The effect of bromhexine on albumin excretion in insulin dependent diabetes.

The effect of the mucolytic agent bromhexine, 72 mg daily for one month, on albumin excretion in insulin dependent diabetes was investigated in a double-blind, randomised, cross-over, placebo-controlled study. Nine patients with normal albumin excretion [overnight albumin excretion rate 3.2 (2.1-8.8) micrograms/min.; mean (range)], six with microalbuminuria [36 (22-95) micrograms/min.] and six with macroalbuminuria [321 (201-1215) micrograms/min.] participated. Albumin excretion was similar after treatment with bromhexine and placebo in all 3 groups [normoalbuminurics 3.6 (1.7-13.5) versus 3.3 (1.9-13.2) micrograms/min.; microalbuminurics 40 (20-128) versus 37 (20-103); macroalbuminurics 396 (247-2160) versus 443 (292-2592)]. Excretion of beta 2-microglobulin and creatinine clearance were identical at the end of each treatment. Blood glucose control and blood pressure remained constant throughout the study in the 3 groups. We conclude that bromhexine 72 mg daily for 1 month had no effect on albumin excretion in IDDM patients with normal and pathological albuminuria.