scholarly journals Kintsugi Imaging of Battery Electrodes: Unambiguously Distinguishing Pores from the Carbon Binder Domain using Pt Deposition

2021 ◽  
Author(s):  
Samuel John Cooper ◽  
Scott Alan Roberts ◽  
Zhao Liu ◽  
Bartłomiej Winiarski
Keyword(s):  
Porous Media ◽  
Focused Ion Beam ◽  
Electrode Materials ◽  
Ion Beam ◽  
Active Material ◽  
Precious Metals ◽  
Lithium Ion ◽  
Porous Electrodes ◽  
Binder Phase ◽  
Cell Energy

The mesostructure of porous electrodes used in lithium-ion batteries strongly influences cell performance. Accurate imaging of the distribution of phases in these electrodes would allow this relationship to be better understood through simulation. However, imaging the nanoscale features in these components is challenging. While scanning electron microscopy is able to achieve the required resolution, it has well established difficulties imaging porous media. This because the flat imaging planes prepared using focused ion beam milling will intersect with the pores, which makes the images hard to interpret as the inside walls of the pores are observed. It is common to infiltrate porous media with resin prior to imaging to help resolve this issue, but both the nanoscale porosity and the chemical similarity of the resins to the battery materials undermine the utility of this approach for most electrodes. In this study, a new technique is demonstrated which uses \textit{in situ} infiltration of platinum to fill the pores and thus enhance their contrast during imaging. Reminiscent of the Japanese art of repairing cracked ceramics with precious metals, this technique is referred to as the \textit{kintsugi} method. The images resulting from applying this technique to a conventional porous cathode are presented and then segmented using a multi-channel convolutional method. We show that while some cracks in active material particles were filled with the carbon binder phase, others remained empty, which will have implications for the rate performance of the cell. Energy dispersive X-ray spectroscopy was used to validate the distribution of phases resulting from image analysis, which also suggested a graded distribution of the binder relative to the carbon addative. The equipment required to use the kintsugi method is commonly available in major research facilities and so we hope that this method will be rapidly adopted to improve the imaging of electrode materials and porous media in general.

scholarly journals Artificial generation of representative single Li-ion electrode particle architectures from microscopy data

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Orkun Furat ◽  
Lukas Petrich ◽  
Donal P. Finegan ◽  
David Diercks ◽  
Francois Usseglio-Viretta ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Electron Backscatter Diffraction ◽  
Ion Beam ◽  
Lithium Ion ◽  
Scale Model ◽  
Multi Scale ◽  
Physics Modeling ◽  
Microscopy Data ◽  
Microscopy Techniques ◽  
Backscatter Diffraction

AbstractAccurately capturing the architecture of single lithium-ion electrode particles is necessary for understanding their performance limitations and degradation mechanisms through multi-physics modeling. Information is drawn from multimodal microscopy techniques to artificially generate LiNi0.5Mn0.3Co0.2O2 particles with full sub-particle grain detail. Statistical representations of particle architectures are derived from X-ray nano-computed tomography data supporting an ‘outer shell’ model, and sub-particle grain representations are derived from focused-ion beam electron backscatter diffraction data supporting a ‘grain’ model. A random field model used to characterize and generate the outer shells, and a random tessellation model used to characterize and generate grain architectures, are combined to form a multi-scale model for the generation of virtual electrode particles with full-grain detail. This work demonstrates the possibility of generating representative single electrode particle architectures for modeling and characterization that can guide synthesis approaches of particle architectures with enhanced performance.

Preparation of Activated Carbon Derived from Water Hyacinth as Electrode Active Material for Li-Ion Supercapacitor

2020 ◽  
Vol 1000 ◽  
pp. 50-57
Author(s):  
Jagad Paduraksa ◽  
Muhammad Luthfi ◽  
Ariono Verdianto ◽  
Achmad Subhan ◽  
Wahyu Bambang Widayatno ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Water Hyacinth ◽  
Electrode Materials ◽  
Storage System ◽  
Active Material ◽  
Lithium Ion ◽  
High Energy ◽  
Specific Power ◽  
Full Cell ◽  
Lithium Ion Capacitor

Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in recent years has improvised LIC performance significantly. One of the active materials of LIC electrodes, activated carbon (AC), can be synthesized from various biomass, one of which is the water hyacinth. Its abundant availability and low utilization make the water hyacinth as a promising activated carbon source. To observe the most optimal physical properties of AC, this study also compares various activation temperatures. In this study, full cell LIC was fabricated using LTO based anode, and water hyacinth derived AC as the cathode. The LIC full cell was further characterized to see the material properties and electrochemical performance. Water hyacinth derived LIC can achieve a specific capacitance of 32.11 F/g, the specific energy of 17.83 Wh/kg, and a specific power of 160.53 W/kg.

Silicon Quantum Dots-Carbon Nanotube Composite as Anode Material for Lithium Ion Battery

2013 ◽  
Vol 1540 ◽  
Author(s):  
Lanlan Zhong ◽  
Andi Xie ◽  
Lorenzo Mangolini
Keyword(s):  
Discharge Capacity ◽  
Silicon Nanoparticles ◽  
Electrode Materials ◽  
Active Material ◽  
Weight Ratio ◽  
Lithium Ion ◽  
Aliphatic Chain ◽  
Deposition Technique ◽  
Weight Content ◽  
Vapor Deposition Technique

ABSTRACTSilicon is a very promising material for anodes of lithium ion batteries. It exhibits a high theoretical capacity of 3579 mAh/g. However, during the lithiation and de-lithiation, silicon materials experience up to a 300% volume change, leading to poor cyclability [1-2]. Research shows that reducing the silicon particle size can mitigate this problem. Carbon nanotubes (CNTs) function well as electrode materials in electrolytic cells because of their high electrical conductivity and surface area. In this work, we combine silicon nanoparticles (Si NPs) and CNTs as anode materials. Si NPs are generated using a plasma-enhanced chemical vapor deposition technique and their surface is modified with a 12-carbon long aliphatic chain to impart solubility in non-polar solvents. They are applied onto a nanotube-based layer using a wet-phase deposition technique. SEM and TEM analysis confirm that they form a conformal coating onto the nanotube surface. The CNTs - Si NPs composite active material is tested in half-cells where lithium foil acts as counter electrode. We have achieved an average of 810 mAh/g discharge capacity for composites with a CNTs to Si NPs weight ratio of 1:1. We expect to be able to increase the discharge capacity by increasing the Si NPs weight content.

Coupled Mechanical and Electrochemical Analyses of Three-Dimensional Reconstructed LiFePO4 by Focused Ion Beam/Scanning Electron Microscopy in Lithium-Ion Batteries

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Sangwook Kim ◽  
Hongjiang Chen ◽  
Hsiao-Ying Shadow Huang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lithium Ion Batteries ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Electrochemical Degradation ◽  
Total Polarization ◽  
Scanning Electron

Limited lifetime and performance degradation in lithium ion batteries in electrical vehicles and power tools is still a challenging obstacle which results from various interrelated processes, especially under specific conditions such as higher discharging rates (C-rates) and longer cycles. To elucidate these problems, it is very important to analyze electrochemical degradation from a mechanical stress point of view. Specifically, the goal of this study is to investigate diffusion-induced stresses and electrochemical degradation in three-dimensional (3D) reconstructed LiFePO4. We generate a reconstructed microstructure by using a stack of focused ion beam-scanning electron microscopy (FIB/SEM) images combined with an electrolyte domain. Our previous two-dimensional (2D) finite element model is further improved to a 3D multiphysics one, which incorporates both electrochemical and mechanical analyses. From our electrochemistry model, we observe 95.6% and 88.3% capacity fade at 1.2 C and 2 C, respectively. To investigate this electrochemical degradation, we present concentration distributions and von Mises stress distributions across the cathode with respect to the depth of discharge (DoD). Moreover, electrochemical degradation factors such as total polarization and over-potential are also investigated under different C-rates. Further, higher total polarization is observed at the end of discharging, as well as at the early stage of discharging. It is also confirmed that lithium intercalation at the electrode-electrolyte interface causes higher over-potential at specific DoDs. At the region near the separator, a higher concentration gradient and over-potential are observed. We note that higher over-potential occurs on the surface of electrode, and the resulting concentration gradient and mechanical stresses are observed in the same regions. Furthermore, mechanical stress variations under different C-rates are quantified during the discharging process. With these coupled mechanical and electrochemical analyses, the results of this study may be helpful for detecting particle crack initiation.

scholarly journals Amorphous LiCoO2-based Positive Electrode Active Materials with Good Formability for All-Solid-State Rechargeable Batteries

MRS Advances ◽  
2018 ◽  
Vol 3 (23) ◽  
pp. 1319-1327 ◽  
Author(s):  
Kenji Nagao ◽  
Yuka Nagata ◽  
Atsushi Sakuda ◽  
Akitoshi Hayashi ◽  
Masahiro Tatsumisago
Keyword(s):  
Solid State ◽  
Electrode Materials ◽  
Active Material ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Rechargeable Batteries ◽  
Positive Electrode ◽  
Active Materials ◽  
Ceramic Electrolyte ◽  
Xrd Patterns

ABSTRACTAmorphous LiCoO2-based positive electrode materials are synthesized by a mechanical milling technique. As a lithium oxy-acid, Li2SO4, Li3PO4, Li3BO3, Li2CO3, and LiNO3 are selected and milled with LiCoO2. XRD patterns indicate that reaction between LiCoO2 and these lithium oxy-acids proceeds. Amorphization mainly occurs, and several broad peaks attributable to cubic LiCoO2 are observed in all the samples. These amorphous active materials show mixed conductivities of electron and lithium ion. All-solid-state cells using the prepared amorphous active materials and the Li2.9B0.9S0.1O3.1 glass-ceramic electrolyte are fabricated and their charge-discharge properties are examined. The cells with only the 80LiCoO2·20Li2SO4 (mol%) and the 80LiCoO2·20Li3PO4 active materials function as secondary batteries. This is because higher lithium ionic conductivities are obtained in the 80LiCoO2·20Li2SO4 and 80LiCoO2·20Li3PO4 active materials than in the others. The largest capacity is obtained in the cell with the 80LiCoO2·20Li2SO4 active material because of its good formability and high lithium ionic conductivity. In addition, the cell with the 80LiCoO2·20Li2SO4 positive electrode active material shows the better cycle and rate performance than that with the crystalline LiCoO2. It is noted that the amorphization with lithium oxy-acids is a promising technique for achieving a novel active material with better electrochemical performance.

scholarly journals Synthesis and Characterization of Li-C Nanocomposite for Easy and Safe Handling

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1483
Author(s):  
Subash Sharma ◽  
Tetsuya Osugi ◽  
Sahar Elnobi ◽  
Shinsuke Ozeki ◽  
Balaram Paudel Jaisi ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Ion Beam ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
High Energy ◽  
Significant Loss ◽  
High Energy Density ◽  
Ambient Conditions ◽  
Safe Handling ◽  
Metallic Lithium

Metallic lithium (Li) anode batteries have attracted considerable attention due to their high energy density value. However, metallic Li is highly reactive and flammable, which makes Li anode batteries difficult to develop. In this work, for the first time, we report the synthesis of metallic Li-embedded carbon nanocomposites for easy and safe handling by a scalable ion beam-based method. We found that vertically standing conical Li-C nanocomposite (Li-C NC), sometimes with a nanofiber on top, can be grown on a graphite foil commonly used for the anodes of lithium-ion batteries. Metallic Li embedded inside the carbon matrix was found to be highly stable under ambient conditions, making transmission electron microscopy (TEM) characterization possible without any sophisticated inert gas-based sample fabrication apparatus. The developed ion beam-based fabrication technique was also extendable to the synthesis of stable Li-C NC films under ambient conditions. In fact, no significant loss of crystallinity or change in morphology of the Li-C film was observed when subjected to heating at 300 °C for 10 min. Thus, these ion-induced Li-C nanocomposites are concluded to be interesting as electrode materials for future Li-air batteries.

scholarly journals 3D-FIB Characterization of Wear in WC-Co Coated Composites

2015 ◽  
Vol 825-826 ◽  
pp. 995-1000 ◽  
Author(s):  
José García ◽  
Thais Carvalho Miranda ◽  
Haroldo Cavalcanti Pinto ◽  
Flavio Soldera ◽  
Frank Mücklich
Keyword(s):  
Stress Field ◽  
Focused Ion Beam ◽  
3D Visualization ◽  
Ion Beam ◽  
Binder Phase ◽  
Axis Direction ◽  
Focused Ion Beam Tomography

In this work 3D visualization of wear in milling inserts has been investigated by Focused Ion Beam tomography. It has been observed that the morphology of the cracks differs in the z-axis direction, allowing particular characteristics of the microstructure and wear evolution to be visible. Two types of cracks develop: principal and lateral cracks. The formation of lateral cracks is strongly influenced by the degradation of the binder phase in the regions surrounding the principal crack. The lateral cracks and the deflection of the main cracks present a particular semi-elliptical geometry, which correlates with the stress field originated during the input of a cycling load in a fatigue condition.

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