Probing BuriedInterfaces in Batteries: Toward Operando Visibilityand Quantitative Diagnosis

Analysis of image sharpness reproducibility on a novel engineered micro-CT scanner with variable geometry and embedded recalibration software

Solids that simultaneously conduct electrons and ions are key elements for the mass transfer and storage required in battery electrodes. Single-phase materials with a high electronic and high ionic conductivity at room temperature are hard to come by, and therefore multiphase systems with separate ion and electron channels have been put forward instead. Here we report on bilayer graphene as a single-phase mixed conductor that demonstrates Li diffusion faster than in graphite and even surpassing the diffusion of sodium chloride in liquid water. To measure Li diffusion, we have developed an on-chip electrochemical cell architecture in which the redox reaction that forces Li intercalation is localized only at a protrusion of the device so that the graphene bilayer remains unperturbed from the electrolyte during operation. We performed time-dependent Hall measurements across spatially displaced Hall probes to monitor the in-plane Li diffusion kinetics within the graphene bilayer and measured a diffusion coefficient as high as 7 × 10-5 cm2 s-1.

The need for absolute accuracy is increasing as semiconductor-manufacturing technologies advance to sub-65nm nodes, since device sizes are reducing to sub-50nm but offsets ranging from 5nm to 20nm are often encountered. While TEM is well-recognized as the most accurate CD metrology, direct comparison between the TEM data and in-line CD data might be misleading sometimes due to different statistical sampling and interferences from sidewall roughness. In this work we explore the capability of CD-AFM as an accurate in-line CD reference metrology. Being a member of scanning profiling metrology, CD-AFM has the advantages of avoiding e-beam damage and minimum sample damage induced CD changes, in addition to the capability of more statistical sampling than typical cross section metrologies. While AFM has already gained its reputation on the accuracy of depth measurement, not much data was reported on the accuracy of CD-AFM for CD measurement. Our main focus here is to prove the accuracy of CD-AFM and show its measuring capability for semiconductor related materials and patterns. In addition to the typical precision check, we spent an intensive effort on examining the bias performance of this CD metrology, which is defined as the difference between CD-AFM data and the best-known CD value of the prepared samples. We first examine line edge roughness (LER) behavior for line patterns of various materials, including polysilicon, photoresist, and a porous low k material. Based on the LER characteristics of each patterning, a method is proposed to reduce its influence on CD measurement. Application of our method to a VLSI nanoCD standard is then performed, and agreement of less than 1nm bias is achieved between the CD-AFM data and the standard's value. With very careful sample preparations and TEM tool calibration, we also obtained excellent correlation between CD-AFM and TEM for poly-CDs ranging from 70nm to 400nm. CD measurements of poly ADI and low k trenches are also reported, and both show good correlation to in-line CD-SEM results.

Investigation of solid electrolyte interphase (SEI) film thickness on a mesophase graphite electrode in the lithium-ion battery is successfully demonstrated by the ex-situ small-angle neutron scattering (SANS) technique for the MGP and the FMGP anodes, after the first charge state and analyzing it precisely by the Guinier–Porod model. SANS data revealed a stable, maximum (150 nm) bi-layer SEI formed on MGP anode (in EC/DMC) at a capacity of 50 mAhg-1 and sluggish above 100 mAhg-1. The SEI formed on the FMGP with and without 3% FEC (in EC/DMC) shows the thickness of 220 nm and 245 nm, respectively, whereas the solvent contains only EC/DEC produce thin SEI of 140 nm. Our primary results make evident that SANS could be employed to better understand the complex microstructure SEI formation and its accurate thickness, on a mesophase graphite anode. Lithium diffusion phenomenon in negative electrodes for Li-ion batteries were studied by using a cold triple-axis spectrometer in-operando neutron scattering. The study on the lithium diffusion mechanism of Li+ diffusion in LiC6 , LiC12 of the MGP and the electrolyte additives (as venylene carbonate, VC) at low temperature (253K or 268K) were very importance for the lithium plating and long cycle. Therefore, SIKA is the instrument good to conduct an experiment at low temperature to understand the Li+ diffusion effect in the cell of NMC/graphite LIB at different temperature in order to give an ideal to improve the battery design and to resolve the lithium plating issue in the low temperature which regarding to the safety. From the qualitative analysis of the phase transition as a function of time and temperature, considering the (00l) peak intensities of graphite to extract the diffraction peaks corresponds to the relative fractions of LiC6 and LiC12 which in turn were related to the amount of Li diffusion through the SEI and the lithium intercalation takes place in the anode. From the spectra, we obtained the intensity of LiC6 diffraction plane is increased with increasing charging capacity yielded with the value of 2064 and 1757 mAh at 298 and 268 K, respectively. While, the intensity of graphite phase is firstly shift from 40º to 39.5º then LiC12 and LiC6 phases were observed with obvious increased intensity. The integrated intensity of LiC6, and LiC12 reflections as a function of time varies with different temperature. At initial charging condition in Fig. 1, the intensity of pure graphite plane centred at 40º is large and also observed the generation of small amount of LiCx (37.1º, LiC6 and 38.9º, LiC12) compounds. This process is observed to be reverse in the case of discharging the cell at 298 and 268 K. At 298 K, decrease in the voltage (3.99 to 2.80 V), the amount of LiC6 is slowly disappears and the amount of LiC12 is maximum, finally observed the graphitic peak with small low angle shift, which confirms the presence of small Li+ into the graphite layer/surface, in the discharge condition. In the case of discharging at 268 K, the LiC6 plane is quickly fading from 3.80 V and disappear. The ratio of capacity of the cell was 86% for 268 K compare with 298 K, which was not consistence with the quantity of LiC6 plane. We also establish the neutron diffraction analysis for the samples prepared with different additives and the results were discussed in detail. In the future, we will also pay attention to the formation of lithium plating which is highly related to the battery safety.

Measurement of the electronic conductivity of porous thin-film battery electrodes poses significant challenges, particularly when the film is attached to a metallic current collector. We have developed a micro-four-line probe and testing procedure that overcomes many of these difficulties while relying on principles similar to commonly used four-point probes. This work describes a mathematical model that enables rapid inversion of the data collected by such experiments to compute two properties: bulk electronic conductivity of the film and contact resistance with the current collector. The model accounts for variable probe and sample geometry and variable resistance between the probe and the sample. Results from 2D and 3D models are presented. The full 3D model combines a Fourier series with the boundary element method to generate a solution that requires significantly less computational cost than a corresponding finite element solution for the same level of accuracy. The model confirms that the ideal probe line spacing is close to the value of the electrode film thickness.

An irradiance profiling system was developed to obtain long-term autonomous measurements of solar irradiance above, within, and under sea ice in the Arctic. Two miniature spectrometers were adopted to sequentially sense light signals collected and transmitted by eight fiber probes deposited at different levels of the sea ice environment. Each spectrometer was aligned to each fiber probe by rotating the spectrometer to the desired angle by using a rotary spectrometer switching device. A small optical probe was developed that could be placed in an auger hole with a diameter of 5 cm and enable a high transmission rate for the light signal. The temperature dependence of the signal output was examined and evaluated over the entire operating temperature range from −50° to +30°C. A signal output correction model was proposed to correct temperature-induced biases in the system output; this was combined with the system spectral sensitivity correction to determine the absolute irradiance entering the system. The performance of the system was examined for two days during the ninth Chinese National Arctic Research Expedition by deploying it in a 185-cm-thick ice pack in the Arctic and measuring the solar irradiance distribution at different levels. The spectral shape of the measured solar irradiance above the sea ice agreed well with that measured using other commercial oceanographic spectroradiometers. The measured optical properties of the sea ice were generally comparable to those of similar ice measured using other instruments.

Neutron techniques provide exceptional sensitivity to light elements, buried interfaces, and bulk transport, making them uniquely suited for probing lithium–sulfur (Li–S) batteries, yet their application remains fragmented and insufficiently standardized. This Review develops a unified mechanistic mapping framework that links neutron observables to Li–S descriptors across multiple length and time scales, spanning fundamental and application‐relevant regimes. Imaging and tomography, small‐angle scattering (SANS), diffraction, reflectometry, quasielastic neutron spectroscopy (QENS), neutron depth profiling (NDP), and prompt‐gamma activation analysis (PGNAA) are integrated to resolve sulfur redox reactions, polysulfide transport, electrolyte and separator behavior, and lithium anode degradation under operando conditions. Practical guidelines are summarized for operando cell architectures, isotopic‐contrast design using H/D and 6 Li substitution, optimization of neutron flux and q‐range, and uncertainty‐aware data treatment. To address limitations in temporal resolution, chemical selectivity, and cross‐study comparability, the Review introduces an AI‐assisted, model‐based data‐fusion framework combining physics‐informed preprocessing with Bayesian optimization and neural‐network modeling. This approach enables quantitative reconstruction of sulfur‐phase evolution, interphase growth, and Li 2 S morphology under realistic conditions. A concluding roadmap identifies priority measurements, standardized metadata schemes, and benchmarks to accelerate reproducible Li–S research across global neutron facilities.

There is little known about the short-term dynamics of groundwater-surface water exchange in losing rivers. This is partly due to the paucity of chemical techniques that can autonomously collect high-frequency data in groundwater bores. Here we present two new instruments for continuous in situ (222)Rn measurement in bores for quantifying the surface water infiltration rate into an underlying or adjacent aquifer. These instruments are based on (222)Rn diffusion through silicone tube membranes, either wrapped around a pole (MonoRad) or strung between two hollow end pieces (OctoRad). They are combined with novel, robust, low-cost Geiger counter (222)Rn detectors which are ideal for long-term autonomous measurement. The down-hole instruments have a quantitative response time of about a day during low flow, but this decreases to <12 h during high-flow events. The setup was able to trace river water bank infiltration during moderate to high river flow during two field experiments. Mass-balance calculations using the (222)Rn data gave a maximum infiltration rate of 2 m d(-1). These instruments offer the first easily constructible system for continuous (222)Rn analysis in groundwater, and could be used to trace surface water infiltration in many environments including rivers, lakes, wetlands, and coastal settings.

Abstract. A new gas chromatograph was used to make measurements of halocarbons at the Cape Verde observatory during late May and early June 2007. The instrument demonstrated its potential for long-term autonomous measurements. Bromoform (CHBr3) exhibits the most variability of all the halocarbons observed, ranging from a background concentration of about 4 ppt to a maximum of &gt;40 ppt during the course of the measurement period. CH2Br2 correlates well with bromoform, suggesting a common regional source. Methyl iodide does not correlate with these bromocarbons, with base levels of around 1–2 ppt and some periods of much higher mixing ratios. Using published bromocarbon emission rates, our chemical transport model studies, presented here, do not reproduce the observations. Local emission magnitudes and CHBr3:CH2Br2 ratios must be increased more in line with the recent observations of Yokouchi et al. (2005) to improve the model to measurement comparison. Even when the model reproduces the observed bromocarbons, modelled BrO is much less than recent tropical observations (Read et al., 2008). A sea salt source seems the likely explanation. When high BrO is reproduced, the model agrees much better with the observed ozone changes, including diurnal variation, during the measurement period but it is suggested that a representation of iodine chemistry in the model is also required.

While many epidemiological studies have examined the health effects of different sizes of ambient particulate matter (PM), the findings have been mixed. PM is a heterogeneous mixture, and its chemical components differ by size, with more combustion related materials in the fine mode and more crustal materials in the coarse mode. This study estimates the risk of mortality associated with exposure to PM2.5 (particulate matter less than 2.5 mu m in aerodynamic diameter) and PM2.5-10 (particulate matter less than 10 mu m and greater than 2.5 mu m in aerodynamic diameter). Long-term measurements of PM2.5 and PM2.5-10 were compared with the all-cause, cardiovascular, and respiratory mortality observed from January 2006 till December 2012 in three large cities in Korea (viz., Seoul, Busan, and Incheon). A time-series analysis based on a quasi-Poisson distribution was used to evaluate the associations of PM2.5 and PM2.5-10 with mortality. A 10 mu g m(-3) increase in PM2.5 (lag01) was associated with an increase of 1.18% (95% CI: 0.64, 1.72), 0.34% (95% CI: 0.03, 0.64), and 0.43% (90% CI: 0.02, 0.95) in the all-cause mortality in Busan, Seoul, and Incheon, respectively, during the study period. An increase in respiratory mortality of 0.52% (95% CI: 0.09, 0.96) and 2.25% (95% CI: 0.38, 4.15) was associated with a 10 mu g m(-3) increase in PM2.5 (lag01) in Seoul and Busan, respectively. Overall, the strongest associations were observed in Busan as well as among the elderly population. Statistically significant associations between ambient PM2.5 and PM2.5-10, and mortality were observed in this study. Exposure to fine particles, which mostly originate in combustion and mobile emissions, showed stronger effects on human health than coarse particles, which mostly originate in natural sources such as soil and mechanical processes.