Mechanism of Ultrafast (Dis)charging of Li Ion Batteries by Heterogeneous Doping of LiFePO4

2010 ◽  
Vol 1263 ◽  
Author(s):  
Stefan Adams ◽  
R. Prasada Rao ◽  
Haiping Choo
Keyword(s):  
Pathway Analysis ◽  
Md Simulations ◽  
Layer By Layer ◽  
Multilayer Systems ◽  
Migration Pathway ◽  
Layer Analysis ◽  
Heterogeneous Doping ◽  
Li Ion ◽  
Surface Modified ◽  
Li Content

AbstractMolecular dynamics (MD) simulations with a dedicated force-field and our bond valence (BV) pathway analysis have been employed to reproduce and explain the experimentally observed ultrafast Li+ transport in surface modified LixFePO4-δ as a consequence of heterogeneous doping, i.e. the Li+ redistribution in the vicinity of the interface between LixFePO4 and a pyrophosphate glass surface layer. Over the usual working temperature range of LIBs Li+ ion conductivity in the surface modified LixFePO4 phase is enhanced by 2-3 orders of magnitude, while the enhancement practically vanishes for T > 700K. Simulations for the bulk phase reproduce the experimental conductivities and the activation energy of 0.57eV (for x ≈ 1). A layer-by-layer analysis of structurally relaxed multilayer systems indicates a continuous variation of Li+ mobility with the distance from the interface and the maximum mobility close to the interface, but Li+ diffusion rate remains enhanced (compared to bulk values) even at the center of the simulated cathode material crystallites. Our BV migration pathway analysis in the dynamic local structure models shows that the ion mobility is related to the extension of unoccupied accessible pathway regions. The change in the extent of Li redistribution across the interface with the overall Li content constitutes a fast pseudo-capacitive (dis)charging contribution.

Layer-by-layer analysis of charge state distribution of field evaporated ions from the W(011) plane

1984 ◽  
Vol 140 (1) ◽  
pp. L253-L258
Author(s):  
Kenji Murakami ◽  
Toshiyuki Adachi ◽  
Tsukasa Kuroda ◽  
Shogo Nakamura
Keyword(s):  
Charge State ◽  
Charge State Distribution ◽  
Layer By Layer ◽  
State Distribution ◽  
Layer Analysis

Superior Quality Rails: Structure-Phase States and Defect Substructure

2014 ◽  
Vol 1013 ◽  
pp. 127-132 ◽  
Author(s):  
Victor Gromov ◽  
Alexei Yuriev ◽  
Yurii F. Ivanov ◽  
Konstantin Morozov ◽  
Sergey Konovalov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase State ◽  
Layer By Layer ◽  
Quantitative Parameters ◽  
Defect Substructure ◽  
Transmission Electron ◽  
Layer Analysis ◽  
Structure Phase

Using transmission electron microscopy methods the layer by layer analysis of the bulk hardened superior quality rails is carried out and the quantitative parameters of structure, phase state and defect substructure gradients are established. It is shown that the interface boundaries globular cementite particles-matrix are the possible places of microcracks initiation.

Electron spectroscopy as applied to the layer-by-layer analysis of hydrocarbon coatings produced by ion-plasma deposition

2014 ◽  
Vol 8 (2) ◽  
pp. 269-273
Author(s):  
V. P. Afanas’ev ◽  
A. N. Ermilov ◽  
I. A. Kostanovsky ◽  
P. M. Tyuryukanov ◽  
A. V. Lubenchenko ◽  
...  
Keyword(s):  
Electron Spectroscopy ◽  
Plasma Deposition ◽  
Layer By Layer ◽  
Ion Plasma ◽  
Layer Analysis

Assembly of Gentamicin and Zn2+ Loaded Coatings on TiO2 Nanotubes to Synergistically Improve the Blood Compatibility, Endothelial Cell Growth and Antibacterial Activities

2020 ◽  
Author(s):  
Changjiang Pan ◽  
Ya Yang ◽  
Youdong Hu ◽  
Li Quan ◽  
Yanchun Wei ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Blood Compatibility ◽  
Antibacterial Properties ◽  
Functional Expression ◽  
Antibacterial Activities ◽  
Layer By Layer ◽  
Zinc Ions ◽  
Continuous Release ◽  
Albumin Adsorption ◽  
Surface Modified

Abstract Titanium and its alloys are widely used in blood contacting implantable and interventional medical devices; however, their biocompatibility is still facing great challenges. In this study, with the aim of improving the biocompatibility and antibacterial activities of titanium, TiO2 nanotubes with a diameter of about 30 nm were firstly prepared on the titanium surface by anodization, followed by the introduction of polyacrylic acid (PAA) and gentamicin (GS) on the nanotube surface by layer-by-layer method, and finally zinc ions were loaded into the surface to improve the bioactivities. The nanotubes have excellent hydrophilic properties and special nanotube-like structure, which can selectively promote the albumin adsorption and enhance the blood compatibility and promote the growth and functional expression of endothelial cells to a certain extent. After the introduction of PAA and GS, although the super-hydrophilicity cannot be achieved, the results of platelet adhesion, cGMP activity, hemolysis rate and partial thromboplastin time (APTT) showed that the blood compatibility was improved, and the blood compatibility was further enhanced after zinc ions loading on the surface. On the other hand, the surface modified materials showed good cytocompatibility to endothelial cells. The introduction of PAA and zinc ions not only promoted the adhesion and proliferation of endothelial cells, but also up-regulated expression of vascular endothelial growth factor (VEGF) and nitric oxide (NO). The slow and continuous release of GS and Zn2+ for more than 14 days, which can significantly improve the antibacterial properties of the materials. Therefore, the present study provides an effective method for the surface modification of titanium-based blood-contacting materials to simultaneously endow with good blood compatibility, endothelial growth behaviors and antibacterial properties.

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