scholarly journals An electron-deficient carbon current collector for anode-free Li-metal batteries

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hyeokjin Kwon ◽  
Ju-Hyuk Lee ◽  
Youngil Roh ◽  
Jaewon Baek ◽  
Dong Jae Shin ◽  
...  
Keyword(s):  
Solid Electrolyte Interphase ◽  
Negative Electrode ◽  
Current Collector ◽  
Nucleation And Growth ◽  
Liquid Electrolyte ◽  
Experimental Measurements ◽  
Electron Deficiency ◽  
Initial Capacity

AbstractThe long-term cycling of anode-free Li-metal cells (i.e., cells where the negative electrode is in situ formed by electrodeposition on an electronically conductive matrix of lithium sourced from the positive electrode) using a liquid electrolyte is affected by the formation of an inhomogeneous solid electrolyte interphase (SEI) on the current collector and irregular Li deposition. To circumvent these issues, we report an atomically defective carbon current collector where multivacancy defects induce homogeneous SEI formation on the current collector and uniform Li nucleation and growth to obtain a dense Li morphology. Via simulations and experimental measurements and analyses, we demonstrate the beneficial effect of electron deficiency on the Li hosting behavior of the carbon current collector. Furthermore, we report the results of testing anode-free coin cells comprising a multivacancy defective carbon current collector, a LixNi0.8Co0.1Mn0.1-based cathode and a nonaqueous Li-containing electrolyte solution. These cells retain 90% of their initial capacity for over 50 cycles under lean electrolyte conditions.

A neutron diffraction cell for studying lithium-insertion processes in electrode materials

1998 ◽  
Vol 31 (5) ◽  
pp. 823-825 ◽  
Author(s):  
Ö. Bergstöm ◽  
A. M. Andersson ◽  
K. Edström ◽  
T. Gustafsson
Keyword(s):  
Neutron Diffraction ◽  
Electrode Materials ◽  
Negative Electrode ◽  
Current Collector ◽  
Neutron Diffraction Study ◽  
Lithium Insertion ◽  
Lithium Electrode ◽  
Extraction Processes ◽  
Li Ion

An electrochemical cell has been constructed forin situneutron diffraction studies of lithium-insertion/extraction processes in electrode materials for Li-ion batteries. Its key components are a Pyrex tube, gold plated on its inside, which functions as a current collector, and a central lithium rod, which serves as the negative electrode. The device is demonstrated here for a neutron diffraction study of lithium extraction from LiMn2O4: a mechanical Celgard©separator soaked in the electrolyte surrounds the lithium electrode. The LiMn2O4powder, mixed with electrolyte, occupies the space between separator and current collector.

scholarly journals Solid-electrolyte interphase nucleation and growth on carbonaceous negative electrodes for Li-ion batteries visualized with in situ atomic force microscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sergey Yu. Luchkin ◽  
Svetlana A. Lipovskikh ◽  
Natalia S. Katorova ◽  
Aleksandra A. Savina ◽  
Artem M. Abakumov ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Solid Electrolyte ◽  
Solid Electrolyte Interphase ◽  
Nucleation And Growth ◽  
Li Ion Batteries ◽  
Force Microscopy ◽  
Electrode Potentials ◽  
Atomic Force ◽  
Li Ion

Abstract Li-ion battery performance and life cycle strongly depend on a passivation layer called solid-electrolyte interphase (SEI). Its structure and composition are studied in great details, while its formation process remains elusive due to difficulty of in situ measurements of battery electrodes. Here we provide a facile methodology for in situ atomic force microscopy (AFM) measurements of SEI formation on cross-sectioned composite battery electrodes allowing for direct observations of SEI formation on various types of carbonaceous negative electrode materials for Li-ion batteries. Using this approach, we observed SEI nucleation and growth on highly oriented pyrolytic graphite (HOPG), MesoCarbon MicroBeads (MCMB) graphite, and non-graphitizable amorphous carbon (hard carbon). Besides the details of the formation mechanism, the electrical and mechanical properties of the SEI layers were assessed. The comparative observations revealed that the electrode potentials for SEI formation differ depending on the nature of the electrode material, whereas the adhesion of SEI to the electrode surface clearly correlates with the surface roughness of the electrode. Finally, the same approach applied to a positive LiNi1/3Mn1/3Co1/3O2 electrode did not reveal any signature of cathodic SEI thus demonstrating fundamental differences in the stabilization mechanisms of the negative and positive electrodes in Li-ion batteries.

In Situ Formed Flexible Three-Dimensional Honeycomb-like Film for LiF/Li3N-riched Hybrid Organic-Inorganic Interphase on Li Metal Anode

2021 ◽  
Author(s):  
Daobin Mu ◽  
Chengwei Ma ◽  
Ge Mu ◽  
Haijian Lv ◽  
Chengcai Liu ◽  
...  
Keyword(s):  
Solid Electrolyte Interphase ◽  
Three Dimensional ◽  
High Energy ◽  
Liquid Electrolyte ◽  
Lithium Metal ◽  
Metal Anode ◽  
Lithium Metal Anode ◽  
Li Metal Anode ◽  
Storage Batteries

The solid-electrolyte interphase (SEI) plays an important role in stabilizing lithium metal anode for high-energy storage batteries. However, the SEI between lithium metal anode and liquid electrolyte is usually unstable...

scholarly journals Driving high capacity anode-free lithium metal batteries under unpressurized and lean electrolyte condition by an electron-deficient current collector

2021 ◽  
Author(s):  
Hyeokjin Kwon ◽  
Ju-Hyuk Lee ◽  
Youngil Roh ◽  
Jaewon Baek ◽  
Dong Jae Shin ◽  
...  
Keyword(s):  
Fermi Level ◽  
Electron Tunneling ◽  
Solid Electrolyte Interphase ◽  
High Capacity ◽  
Current Collector ◽  
Liquid Electrolyte ◽  
Nucleation Density ◽  
Lithium Metal ◽  
Lithium Metal Batteries ◽  
Critical Issues

Abstract The long-term cycling of anode-free lithium metal batteries (AF-LMBs) with a liquid electrolyte is hindered by the formation of inhomogeneous solid electrolyte interphase (SEI) on current collector and the subsequent irregular Li deposition. Here, we report the nano-window (NW) defect-enriched carbon current collector with a lowered Fermi level, which can address the critical issues. The low Fermi-level surface induces a defect-free SEI layer by alleviating electron tunneling at the interface, and leads to high Li nucleation density and lateral Li growth via Li-C orbital hybridization. DFT calculations and spectroscopic analyses elucidate that these effects are rooted in the electron deficiency of the NW defect structure. An AF-LMB employing an NCM811 cathode, NW-enriched 3D-current collector, and carbonate liquid electrolyte exhibits 90% capacity retention for over 50 cycles under unpressurized and lean electrolyte conditions. The defect chemistry presents a new design principle of tuning the electronic structure of current collectors enabling 3-dimensional Li deposition in AF-LMBs.

Role of boundaries in the crystallization of amorphous films

1988 ◽  
Vol 46 ◽  
pp. 626-627
Author(s):  
D. A. Smith
Keyword(s):  
Low Temperature ◽  
Amorphous State ◽  
Nucleation And Growth ◽  
Amorphous Films ◽  
Island Nucleation ◽  
Surface Steps ◽  
Transmission Electron ◽  
Component Systems ◽  
Temperature Deposition

The nucleation and growth processes which lead to the formation of a thin film are particularly amenable to investigation by transmission electron microscopy either in situ or subsequent to deposition. In situ studies have enabled the observation of island nucleation and growth, together with addition of atoms to surface steps. This paper is concerned with post-deposition crystallization of amorphous alloys. It will be argued that the processes occurring during low temperature deposition of one component systems are related but the evidence is mainly indirect. Amorphous films result when the deposition conditions such as low temperature or the presence of impurities (intentional or unintentional) preclude the atomic mobility necessary for crystallization. Representative examples of this behavior are CVD silicon grown below about 670°C, metalloids, such as antimony deposited at room temperature, binary alloys or compounds such as Cu-Ag or Cr O2, respectively. Elemental metals are not stable in the amorphous state.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals Probing the Na metal solid electrolyte interphase via cryo-transmission electron microscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bing Han ◽  
Yucheng Zou ◽  
Zhen Zhang ◽  
Xuming Yang ◽  
Xiaobo Shi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid Electrolyte ◽  
Solid Electrolyte Interphase ◽  
Metal Electrode ◽  
Liquid Electrolyte ◽  
Battery Materials ◽  
Cryogenic Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Fluoroethylene Carbonate

AbstractCryogenic transmission electron microscopy (cryo-TEM) is a valuable tool recently proposed to investigate battery electrodes. Despite being employed for Li-based battery materials, cryo-TEM measurements for Na-based electrochemical energy storage systems are not commonly reported. In particular, elucidating the chemical and morphological behavior of the Na-metal electrode in contact with a non-aqueous liquid electrolyte solution could provide useful insights that may lead to a better understanding of metal cells during operation. Here, using cryo-TEM, we investigate the effect of fluoroethylene carbonate (FEC) additive on the solid electrolyte interphase (SEI) structure of a Na-metal electrode. Without FEC, the NaPF6-containing carbonate-based electrolyte reacts with the metal electrode to produce an unstable SEI, rich in Na2CO3 and Na3PO4, which constantly consumes the sodium reservoir of the cell during cycling. When FEC is used, the Na-metal electrode forms a multilayer SEI structure comprising an outer NaF-rich amorphous phase and an inner Na3PO4 phase. This layered structure stabilizes the SEI and prevents further reactions between the electrolyte and the Na metal.

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