Liquid Structure with Nano-Heterogeneity Promotes Cationic Transport in Concentrated Electrolytes.
ACS Nano
; 11(10): 10462-10471, 2017 10 24.
Article
en En
| MEDLINE
| ID: mdl-29016112
ABSTRACT
Using molecular dynamics simulations, small-angle neutron scattering, and a variety of spectroscopic techniques, we evaluated the ion solvation and transport behaviors in aqueous electrolytes containing bis(trifluoromethanesulfonyl)imide. We discovered that, at high salt concentrations (from 10 to 21 mol/kg), a disproportion of cation solvation occurs, leading to a liquid structure of heterogeneous domains with a characteristic length scale of 1 to 2 nm. This unusual nano-heterogeneity effectively decouples cations from the Coulombic traps of anions and provides a 3D percolating lithium-water network, via which 40% of the lithium cations are liberated for fast ion transport even in concentration ranges traditionally considered too viscous. Due to such percolation networks, superconcentrated aqueous electrolytes are characterized by a high lithium-transference number (0.73), which is key to supporting an assortment of battery chemistries at high rate. The in-depth understanding of this transport mechanism establishes guiding principles to the tailored design of future superconcentrated electrolyte systems.
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Bases de datos:
MEDLINE
Asunto principal:
Electrólitos
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Nanopartículas
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Simulación de Dinámica Molecular
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Hidrocarburos Fluorados
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Imidas
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Litio
Idioma:
En
Revista:
ACS Nano
Año:
2017
Tipo del documento:
Article
País de afiliación:
Estados Unidos