Ultrafast Lithium Migration by Heterogeneous Doping in Surface Modified LixFePO4

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.

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Analytical Electron Microscopy of Surface-Modified Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118291 ◽

1985 ◽

Vol 43 ◽

pp. 276-279

Author(s):

P. S. Sklad

Keyword(s):

Electron Microscopy ◽

Analytical Electron Microscopy ◽

Theoretical Models ◽

Ceramic Materials ◽

Solute Concentration ◽

Second Phase ◽

Analytical Electron ◽

Implantation Techniques ◽

Lattice Damage ◽

Surface Modified

Over the past several years, it has become increasingly evident that materials for proposed advanced energy systems will be required to operate at high temperatures and in aggressive environments. These constraints make structural ceramics attractive materials for these systems. However it is well known that the condition of the specimen surface of ceramic materials is often critical in controlling properties such as fracture toughness, oxidation resistance, and wear resistance. Ion implantation techniques offer the potential of overcoming some of the surface related limitations.While the effects of implantation on surface sensitive properties may be measured indpendently, it is important to understand the microstructural evolution leading to these changes. Analytical electron microscopy provides a useful tool for characterizing the microstructures produced in terms of solute concentration profiles, second phase formation, lattice damage, crystallinity of the implanted layer, and annealing behavior. Such analyses allow correlations to be made with theoretical models, property measurements, and results of complimentary techniques.

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SPECTRAL CHARACTERIZATION OF REDOX-ACTIVE PRUSSIAN BLUE ON METALLATED PLASMA POLYMER SURFACE MODIFIED CARBON ELECTRODES USING PHOTOTHERMAL DETECTION

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1983645 ◽

1983 ◽

Vol 44 (C6) ◽

pp. C6-285-C6-290 ◽

Cited By ~ 3

Author(s):

J. W. Childers ◽

A. L. Crumbliss ◽

P. S. Lugg ◽

R. A. Palmer ◽

N. Morosoff ◽

...

Keyword(s):

Prussian Blue ◽

Polymer Surface ◽

Spectral Characterization ◽

Plasma Polymer ◽

Carbon Electrodes ◽

Redox Active ◽

Surface Modified

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Surface modified PTFE promotes endothelial cell adhesion and simultaneously inhibits the attachment of platelets and bacteria

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-0034-1367130 ◽

2014 ◽

Vol 62 (S 01) ◽

Cited By ~ 1

Author(s):

M. Gabriel ◽

H. Weiler ◽

U. Mehlhorn ◽

C.-F. Vahl

Keyword(s):

Cell Adhesion ◽

Endothelial Cell ◽

Surface Modified ◽

Endothelial Cell Adhesion

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Experimental and Theoretical Comparable Study of Pure and Zinc Porphyrin Surface Modified ZnO Nanorod Arrays for Hybrid Solar Cell Applications

10.32792/utq/utjsci/vol7/2/26 ◽

2020 ◽

pp. 114-119

Keyword(s):

Solar Cell ◽

Electrochemical Impedance ◽

Hybrid Solar Cell ◽

Cell Performance ◽

Solar Cell Performance ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

Annealing Effects ◽

Vertically Aligned ◽

Surface Modified

Experimental and theoretical study Porphyrin-grafted ZnO nanowire arrays were investigated for organic/inorganic hybrid solar cell applications. Two types of porphyrin – Tetra (4-carboxyphenyle) TCPP and meso-Tetraphenylporphine (Zinc-TPP)were used to modify the nanowire surfaces. The vertically aligned nanowires with porphyrin modifications were embedded in graphene-enriched poly (3-hexylthiophene) [G-P3HT] for p-n junction nanowire solar cells. Surface grafting of ZnO nanowires was found to improve the solar cell efficiency. There are different effect for the two types of porphyrin as results of Zn existing. Annealing effects on the solar cell performance were investigated by heating the devices up to 225 °C in air. It was found that the cell performance was significantly degraded after annealing. The degradation was attributed to the polymer structural change at high temperature as evidenced by electrochemical impedance spectroscopy measurements.

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