Detection Of Subsurface Structures Research Articles

In Situ Imaging Comparison of Lithium Electrodeposits By Neutron and X-Ray (Synchrotron and Laboratory) Tomography

Most of the post-Lithium-ion (Li-ion) devices, such as Li–sulfur, Li–O2, or all-solid-state Li batteries, have in common an negative electrode made of metallic Li.1 The main failure mode of Li based batteries is the inhomogeneity of the Li electrodeposits onto the Li metal negative electrode during charge steps, leading to dendrite growth and low Coulombic efficiency.2 Tomography and radiography imaging techniques are now vastly employed for battery materials analysis thanks to the possibility to perform noninvasive in situ and operando experiments.3 X-ray tomography is a powerful tool for studying dendrites as it provides useful information about their locations, dynamics, and microstructures. However, the use of neutron tomography is scarcely reported for Li electrodeposit analysis due to the difficulty to reach sufficient image resolution to capture the deposit microstructure, that is, typically below 10 to 20 µm. Furthermore, the different interactions of X-rays and neutrons with Li, which has significantly different opacity in the two cases, make the two techniques highly complementary.4 Notably, the capacity of neutrons to discern different Li isotopes is pivotal to get insight into the composition of Li deposits, by distinguishing between Li originating from an electrode (6Li in this study) and Li originating from the Li salt electrolyte (mainly in 7Li here). Indeed, the theoretical linear neutron attenuation coefficient of 6Li is about 15 and 2,000 times larger than that of natural Li and 7Li, respectively.In this study, we report as a proof of concept, an in situ neutron tomography imaging of Li electrodeposits in a cycled Li symmetric cell (see Figure 1).5 The electrochemical cell comprises a natural Li electrode, a 6Li electrode, and a deuterated liquid electrolyte. The neutron tomography is compared with X-ray tomography images of the same electrochemical cell acquired both at an X-ray synchrotron beamline and at a laboratory X-ray tomograph. Neutron tomography is shown to be compatible with in situ analysis and capable of capturing the overall morphology of the Li deposits in good accordance with X-ray tomography analyses. References M. S. Whittingham, Lithium batteries and cathode materials. Chem. Rev. 104 (2004) 4271.Z. Li et al., A review of Li deposition in Li-ion and Li metal secondary batteries. J. Power Sources 254 (2014) 168.K. Harry et al., Detection of subsurface structures underneath dendrites formed on cycled Li metal electrodes, Nat. Mater. 13 (2014) 69.M. Strobl et al., Advances in neutron radiography and tomography. J. Phys. D: Appl. Phys. 42 (2009) 243001.L. Magnier et al., Tomography imaging of Li electrodeposits using Neutron, synchrotron X-ray, and laboratory X-ray sources: A comparison. Front. Energy Res., 9 (2021) 657712. Figure 1

A High-Speed, Light-Weight Scalar Magnetometer Bird for km Scale UAV Magnetic Surveying: On Sensor Choice, Bird Design, and Quality of Output Data

Magnetic surveying is a widely used and cost-efficient remote sensing method for the detection of subsurface structures at all scales. Traditionally, magnetic surveying has been conducted as ground or airborne surveys, which are cheap and provide large-scale consistent data coverage, respectively. However, ground surveys are often incomplete and slow, whereas airborne surveys suffer from being inflexible, expensive and characterized by a reduced signal-to-noise ratio, due to increased sensor-to-source distance. With the rise of reliable and affordable survey-grade Unmanned Aerial Vehicles (UAVs), and the developments of light-weight magnetometers, the shortcomings of traditional magnetic surveying systems may be bypassed by a carefully designed UAV-borne magnetometer system. Here, we present a study on the development and testing of a light-weight scalar field UAV-integrated magnetometer bird system (the CMAGTRES-S100). The idea behind the CMAGTRES-S100 is the need for a high-speed and flexible system that is easily transported in the field without a car, deployable in most terrain and weather conditions, and provides high-quality scalar data in an operationally efficient manner and at ranges comparable to sub-regional scale helicopter-borne magnetic surveys. We discuss various steps in the development, including (i) choice of sensor based on sensor specifications and sensor stability tests, (ii) design considerations of the bird, (iii) operational efficiency and flexibility and (iv) output data quality. The current CMAGTRES-S100 system weighs ∼5.9 kg (including the UAV) and has an optimal surveying speed of 50 km/h. The system was tested along a complex coastal setting in Brittany, France, targeting mafic dykes and fault contacts with magnetite infill and magnetite nuggets (skarns). A 2.0 × 0.3 km area was mapped with a 10 m line-spacing by four sub-surveys (due to regulatory restrictions). The sub-surveys were completed in 3.5 h, including >2 h for remobilisation and the safety clearance of the area. A noise-level of ±0.02 nT was obtained and several of the key geological structures were mapped by the system.

A Facile and Scalable Processing Method for 3-D Nanostructured Copper Current Collectors to Enable High Energy Li-Metal Batteries

Lithium metal is a promising anode for high-energy-density batteries owing to its high theoretical capacity and highly negative electrochemical potential. However, its commercial application is stalled by the undesired dendritic growth of lithium during cycling.[1]Among all kinds of promising approaches (e.g. electrolyte engineering, interfacial engineering, use of solid electrolyte and use of 3-D structured current collectors, etc. ) [2], 3-D structured current collectors represent some new promises as they can effectively increase Li nucleation sites and reduce local current. However, most of these successes are at lab-scale with coin cells and most of the methods are sophisticated and expensive, not scalable and compatible with the roll-to-roll manufacturing processes of current Li-ion battery industry. Here we report a facile electrodeposition process for low- cost, scalable fabrication of copper current collectors with 3-D architected porous structures composed of interconnected Cu nanoparticles.[3]Compared to flat foil current collectors, the deposited 3-D nanostructured Cu current collector has much larger active surfaces area, thus effectively reduces the actual current density for the same apparent current and lowers the possibility of triggering dendritic growth. During Li plating process, Li can be accommodated in the porous structure and on the top surface of the 3-D nanostructured Cu current collector, which effectively suppresses Li dendrite formation and provides a very high practical Li storage areal capacity. The nanoporous electrodeposition coated Cu foil can be produced with very low cost and this foil can be seamlessly incorporated into current Li-ion battery production with no major modifications required. The electrodeposition method also provides great flexibility and tunability of the deposited structure, which suggests more Li may be accommodated and ultrahigh energy density batteries may be developed along this promising approach. Harry, K.J., et al., Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes.Nat. Mater., 2014. 13(1): p. 69-73. Lin, D., Y. Liu, and Y. Cui, Reviving the lithium metal anode for high-energy batteries.Nat. Nanotechnol, 2017. 12(3): p. 194-206. Ma, X., Z. Liu, and H. Chen, Facile and scalable electrodeposition of copper current collectors for high-performance Li-metal batteries.Nano Energy, 2019. 59: p. 500-507.

In Situ Characterization of Lithium Deposition and Microstructure Evolution of Silicon Anodes By Synchrotron X-Ray Imaging

Advanced lithium batteries are crucial for next-generation energy storage systems such as portable electronics and electric vehicles. Due to a low specific capacity (372 mAh/g) batteries using traditional graphite-based anode materials can hardly meet the increasing demands of light weight and high energy density. With theoretical specific capacities that are approximately 10 times higher than that of conventional graphite anodes metallic lithium (3860 mAh/g) and silicon (4200 mAh/g) anodes are regarded as two excellent candidates. Specifically, the energy density of batteries could be dramatically increased approximately from 250 Wh/kg to 440 Wh/kg by replacing graphite with lithium anodes.[1] However these two promising anodes suffer from the dramatic volume change due to microstructure degradation and low coulombic efficiency derived from unstable solid electrolyte interphase (SEI) during cycling. In addition, the dendritic and/or fiber-like deposition on lithium anode could initiate an internal short circuit and thus leads to a fast battery failure. Despite great progress recently achieved on improving electrochemical performance, a clear picture of the microstructure degradation of electrode and battery failure mechanisms is still elusive, largely due to a lack of feasible in situ characterization techniques. Synchrotron X-ray imaging has evolved into a tool of choice allowing in situ or operando analysis of the internal morphology/structure evolution non-invasively.[2, 3] With this technique the internal microstructure of a silicon electrode in a lithium ion battery was visualized during battery operation.[4] The silicon particles were found to change their sizes upon lithiation/delithiation and the changes could be quantified. An expansion prolongation phenomenon of Si particle was discovered involving that some particles continue expanding even after switching the battery current direction and shrinkage would be expected. In addition, Li deposition at the Li/separator interface as well as within a porous carbon matrix was visualized and quantified three dimensionally. The study provides new basic insights into expansion/shrinkage processes inside Si particles and uncovers the Li deposition behavior that can hardly be probed by surface imaging techniques. Finally investigations on Li anode degradation mechanisms are presented.[5] References [1] D. Lin, Y. Liu, Y. Cui, Reviving the lithium metal anode for high-energy batteries. Nature Nanotechnology, 2017, 12, 194. [2] M. Ebner, F. Marone, M. Stampanoni, V. Wood, Visualization and quantification of electrochemical and mechanical degradation in Li ion batteries. Science, 2013, 342, 716-720. [3] K. J. Harry, D. T. Hallinan, D. Y. Parkinson, A. A. MacDowell, N. P. Balsara, Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes. Nat Mater, 2014, 13, 69-73. [4] K. Dong, H. Markötter, F. Sun et al., In situ and Operando Tracking of Microstructure and Volume Evolution of Silicon Electrodes by using Synchrotron X-ray Imaging. ChemSusChem, doi:10.1002/cssc.201801969. [5] Fu Sun, Xin He, Xiaoyu Jiang, et al., Advancing Knowledge of Electrochemically Generated Lithium Microstructure and Performance Decay of Lithium Ion Battery by Synchrotron X-ray Tomography, Materials Today, accepted.

Molecular Dynamics Simulations of Ion Transport in Poly-Ethylene Oxide

Solid polymers are becoming a promising alternative option as an electrolyte material in lithium ion batteries [1,2,3]. Solid polymer electrolytes have certain advantages over traditional electrolytes – non-flammability, good electrochemical and mechanical stability, and ability to hinder the growth of dendrites at electrode surfaces [4,5]. Poly-ethylene oxide (PEO) is one such polymer which has been considered a viable option due to its ability to solvate lithium ions and its relatively high ion conductivities. However, the bulk Li-ion conductivities even in PEO at room temperature are at least an order of magnitude less than the traditional liquid electrolytes [2,6]. In this study, we explore the influence of ion concentration and pressure on the Li-ion transport mechanism and in turn on its conductivity in PEO by performing molecular dynamics (MD) simulations of a lithium salt (lithium bis(trifluoromethane) sulfonamide (LiTFSI)) in polymer matrix of poly-ethylene oxide (PEO). We explored the influence of pressure to examine if it has any role in increasing the performance of PEO as an electrolyte. We computed parameters like diffusivity, conductivity and transference numbers that are crucial in determining the performance of PEO as a potential electrolyte for lithium ion batteries. We observe that diffusivity and conductivity decrease with increase in pressure while transference number remain almost independent. The simulation framework can be further used to explore polymers other than PEO as an electrolyte material or to test different block copolymers based on PEO. [1] F. M. Gray. Solid polymer electrolytes: fundamentals and technological applications (pp. 83-93). New York: VCH (1991). [2] D. T. Hallinan Jr., & N. P. Balsara. Polymer electrolytes. Annual review of materials research, 43, 503-525 (2013). [3] S. Mogurampelly, O. Borodin, & V. Ganesan. Computer simulations of ion transport in polymer electrolyte membranes. Annual review of chemical and biomolecular engineering, 7, 349-371 (2016). [4] F. M. Gray. Polymer electrolytes. Royal Society of Chemistry (1997). [5] K. J. Harry, D. T. Hallinan, D. Y. Parkinson, A. A. MacDowell, & N. P. Balsara. Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes. Nature materials, 13(1), 69.4 (2014). [6] A. A. Teran, M. H. Tang, S. A. Mullin, & N. P. Balsara. Effect of molecular weight on conductivity of polymer electrolytes. Solid State Ionics, 203(1), 18-21 (2011). Figure 1

Subsurface modeling of mud volcanoes, using density model and analysis of seismic velocity

Detection of subsurface structures by means of gravity method can be used to determine mass distribution and density contrast of rock units. This distribution could be detected by different geophysical methods, especially gravity method. However, gravity techniques have some drawbacks and can't be always successful in distinguishing subsurface structures. Performance of the gravity technique could be further improved by simultaneous combination and introducing additional information from other geophysical data. This study used existing relation between seismic and gravity methods to better clarify subsurface structures. This relationship relates mass distribution of the medium to velocity of wave propagation in that media. This method was applied on an area that consists of three mud volcanoes. After completion of the primary model by forward modeling, mass distribution and analysis of seismic velocity were provided on a 2-D profile. Bouguer anomaly map of gravity data of the area was obtained and negative anomalies were identified. These negative anomalies could be related to the existence of mud volcanoes. A 2-D seismic line was also acquired over the greatest mud volcano, as additional information for direct modeling. The Gardner equation was used for further velocity estimation by density values. This velocity model also compared with seismic velocity analysis for evaluation. The final results indicated that density modeling and the use of seismic velocity model increases the resolution of subsurface structures imaging. Separation of subsurface layers was implemented correctly in the velocity model resulting from gravity data and subsurface discontinuities of the area that become more obvious by this technique.

From surface to intracellular non-invasive nanoscale study of living cells impairments

Among the enduring challenges in nanoscience, subsurface characterization of living cells holds major stakes. Developments in nanometrology for soft matter thriving on the sensitivity and high resolution benefits of atomic force microscopy have enabled detection of subsurface structures at the nanoscale. However, measurements in liquid environments remain complex, in particular in the subsurface domain. Here we introduce liquid-mode synthesizing atomic force microscopy (l-MSAFM) to study both the inner structures and the chemically induced intracellular impairments of living cells. Specifically, we visualize the intracellular stress effects of glyphosate on living keratinocytes skin cells. This new approach, l-MSAFM, for nanoscale imaging of living cell in their physiological environment or in presence of a chemical stress agent could resolve the loss of inner structures induced by glyphosate, the main component of a well-known pesticide (RoundUp™). This firsthand ability to monitor the cell’s inner response to external stimuli non-destructively and in liquid, has the potential to unveil critical nanoscale mechanisms of life science.

Detection of subsurface structures underneath dendrites formed on cycled lithium metal electrodes

Failure caused by dendrite growth in high-energy-density, rechargeable batteries with lithium metal anodes has prevented their widespread use in applications ranging from consumer electronics to electric vehicles. Efforts to solve the lithium dendrite problem have focused on preventing the growth of protrusions from the anode surface. Synchrotron hard X-ray microtomography experiments on symmetric lithium-polymer-lithium cells cycled at 90 °C show that during the early stage of dendrite development, the bulk of the dendritic structure lies within the electrode, underneath the polymer/electrode interface. Furthermore, we observed crystalline impurities, present in the uncycled lithium anodes, at the base of the subsurface dendritic structures. The portion of the dendrite protruding into the electrolyte increases on cycling until it spans the electrolyte thickness, causing a short circuit. Contrary to conventional wisdom, it seems that preventing dendrite formation in polymer electrolytes depends on inhibiting the formation of subsurface structures in the lithium electrode.

Comparison Between Conventional Arrays in 2D Electrical Resistivity Imaging Technique for Shallow Subsurface Structure Detection of the University of Technology

Comparison Between Conventional Arrays in 2D Electrical Resistivity Imaging Technique for Shallow Subsurface Structure Detection of the University of Technology

Coaxial Needle Insertion Assistant With Enhanced Force Feedback

Many medical procedures involving needle insertion into soft tissues, such as anesthesia, biopsy, brachytherapy, and placement of electrodes, are performed without image guidance. In such procedures, haptic detection of changing tissue properties at different depths during needle insertion is important for needle localization and detection of subsurface structures. However, changes in tissue mechanical properties deep inside the tissue are difficult for human operators to sense, because the relatively large friction force between the needle shaft and the surrounding tissue masks the smaller tip forces. A novel robotic coaxial needle insertion assistant, which enhances operator force perception, is presented. This one-degree-of-freedom cable-driven robot provides to the operator a scaled version of the force applied by the needle tip to the tissue, using a novel design and sensors that separate the needle tip force from the shaft friction force. The ability of human operators to use the robot to detect membranes embedded in artificial soft tissue was tested under the conditions of 1) tip force and shaft force feedback, and 2) tip force only feedback. The ratio of successful to unsuccessful membrane detections was significantly higher (up to 50%) when only the needle tip force was provided to the user.

Curvilinear Structure Enhancement and Detection in Geophysical Images

In this paper, we propose a method for automatic enhancement and identification of partial curvilinear structures. The accurate identification of line structures in geophysical images plays an important role in geophysical interpretation and the detection of subsurface structures. The method was applied on geophysical images in an effort to recognize the linear patterns of subsurface architectural structures that exist in archaeological sites. To our knowledge, the problem of identification of curvilinear structures in geophysical images for archaeological sites is faced for the first time. The method efficiently combines a rotation- and scale-invariant filter and a pixel-labeling method, providing a robust enhancement and detection of mostly line structures in 2-D grayscale images, respectively. Experimental results on real and synthetic images and comparison with existing methods in the literature indicated the reliable performance of the proposed scheme.

Simulation of radar sounder echo from lunar surface and subsurface structure

Space-borne high frequency (HF) radar sounder is an effective tool for investigation of lunar subsurface structure in lunar exploration. The primary strategy of radar sounder technology for subsurface structure detection is utilization of the nadir echoes time delay and intensity difference from the lunar surface and subsurface. It is important to fully understand electromagnetic wave propagation, scattering, and attenuation through the lunar media in order to retrieve information of lunar layering structure from weak nadir echoes of the subsurface, which is simultaneously interfered by strong off-nadir surface clutters. Based on the Kirchhoff approximation (KA) of rough surface scattering and the ray tracing of geometric optics, a numerical simulation of radar echoes from lunar layering structures is developed. According to the lunar surface feature, the topography of mare and highland surfaces is numerically generated, and the triangulated network is employed to make digital elevations of the whole lunar surface. Scattering from the lunar surface and subsurface is numerically calculated using KA approach. Radar echoes and its range images are numerically simulated, and their dependence on the parameters of lunar layering interfaces is discussed. The approach of this paper can also be utilized to investigate subsurface structures in Mars and other planetary exploration.

Suitability of CASI and ATM airborne remote sensing data for archaeological subsurface structure detection under different land cover: the Arpi case study (Italy)

In this paper multi-sensor airborne remote sensing has been applied to the Arpi archaeological area of southern Italy to assess its suitability for detecting and locating subsurface archaeological structures and to delineate subsurface remains beyond the current limits of ground geophysical data. To this aim, the capability of CASI and ATM reflectances in the VIS–NIR spectral range and the ATM apparent thermal inertia for subsurface archaeological prospection have been assessed at different sites of the Arpi archaeological area. First, linear spectral mixture analysis has been applied to CASI and ATM images to retrieve the dominant land cover for the selected subsurface structures, and then, the spectral bands most effective for the archaeological buried structure detection as a function of the land cover characteristics have been evaluated. The results reveal that multi/hyperspectral airborne remote sensing data can represent an effective and rapid tool to detect subsurface structures within different land cover contexts. Therefore, the proposed methodology can be used to perform a preliminary analysis of those areas where large cultural heritage assets occur by prioritizing and localizing the sites where to apply archaeological prospection.

Evaluation of the Electromagnetic Gradiometer Concept for Detection of Underground Structures—Theory and Application

An improved capability for subsurface structure detection is needed to support military and non‐proliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the U.S. Department of Energy program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initiated an electromagnetic induction (EMI) project to evaluate low frequency electromagnetic (EM) techniques for subsurface structure detection. Low frequency, in this case, extends from kilohertz to hundreds of kilohertz. An EM gradiometer survey procedure had already been utilized for borehole imaging of coal seams and had successfully been applied in a surface mode to detect a drug smuggling tunnel. The SNL project has focused on building upon the success of that procedure and applying it to surface and low altitude airborne platforms. Part of SNL's work with Raton Technology Research has focused on improving that technology through improved hard...

The optoacoustic effect in the infrared: some applications

The use of the optoacoustic effect makes Fourier spectroscopy and the operation of optically pumped gas lasers easier. Applied to imaging it allows the detection of subsurface structure in metal.

Subsurface structures of solids by scanning photoacoustic microscopy

Definitive experimental evidence is given for the nondestructive detection of subsurface structures of solids by the technique of scanning photoacoustic microscopy (SPAM). In the case of the ceramic materials studied, the thickness of the surface layer probed is dictated by the thermal diffusion length δth which scales as f−1/2. For a chopping frequency f∼100 Hz, δth is on the order of 100 μm. This demonstrates the advantages of SPAM over conventional microscopy in investigating structures beneath the surface.