scholarly journals Modeling Lithium Transport and Electrodeposition in Ionic-Liquid Based Electrolytes

2021 ◽  
Vol 9 ◽  
Author(s):  
Guanchen Li ◽  
Charles W. Monroe
Keyword(s):  
Ionic Liquid ◽  
Electrical Response ◽  
Lithium Ion ◽  
Transference Number ◽  
Liquid Electrolyte ◽  
Double Layers ◽  
Exchange Reactions ◽  
Ionic Liquid Electrolyte ◽  
Mechanical Coupling ◽  
Chemomechanical Coupling

Purely ionic electrolytes—wherein ionic liquids replace neutral solvents—have been proposed to improve lithium-ion-battery performance, on the basis that the unique microscopic characteristics of polarized ionic-liquid/electrode interfaces may improve the selectivity and kinetics of interfacial lithium-exchange reactions. Here we model a “three-ion” ionic-liquid electrolyte, composed of a traditional ionic liquid and a lithium salt with a common anion. Newman's concentrated-solution theory is extended to account for space charging and chemomechanical coupling. We simulate electrolytes in equilibrium and under steady currents. We find that the local conductivity and lithium transference number in the diffuse double layers near interfaces differ considerably from their bulk values. The mechanical coupling causes ion size to play a crucial role in the interface's electrical response. Interfacial kinetics and surface charge on the electrodes both affect the apparent transport properties of purely ionic electrolytes near interfaces. Larger ionic-liquid cations and anions may facilitate interfacial lithium-exchange kinetics.

A novel boron-based ionic liquid electrolyte for high voltage lithium-ion batteries with outstanding cycling stability

2018 ◽  
Vol 283 ◽  
pp. 111-120 ◽  
Author(s):  
Fuxiao Liang ◽  
Jiali Yu ◽  
Jiahui Chen ◽  
Dong Wang ◽  
Chengdong Lin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Lithium Ion Batteries ◽  
High Voltage ◽  
Lithium Ion ◽  
Liquid Electrolyte ◽  
Cycling Stability ◽  
Ionic Liquid Electrolyte

Elevated Temperature Lithium-Ion Batteries Containing SnO2Electrodes and LiTFSI-Pip14TFSI Ionic Liquid Electrolyte

2017 ◽  
Vol 164 (4) ◽  
pp. A701-A708 ◽  
Author(s):  
Solveig Böhme ◽  
Manfred Kerner ◽  
Johan Scheers ◽  
Patrik Johansson ◽  
Kristina Edström ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Elevated Temperature ◽  
Lithium Ion Batteries ◽  
Lithium Ion ◽  
Liquid Electrolyte ◽  
Ionic Liquid Electrolyte

Symmetric lithium-ion cell based on lithium vanadium fluorophosphate with ionic liquid electrolyte

2011 ◽  
Vol 56 (3) ◽  
pp. 1344-1351 ◽  
Author(s):  
Larisa S. Plashnitsa ◽  
Eiji Kobayashi ◽  
Shigeto Okada ◽  
Jun-ichi Yamaki
Keyword(s):  
Ionic Liquid ◽  
Lithium Ion ◽  
Liquid Electrolyte ◽  
Ionic Liquid Electrolyte ◽  
Lithium Ion Cell

scholarly journals Improving Cycle Life Through Fast Formation Using a Super-Concentrated Phosphonium Based Ionic Liquid Electrolyte for Anode-Free and Lithium Metal Batteries

2021 ◽  
Author(s):  
Thushan Pathirana ◽  
Dmitrii Rakov ◽  
Fangfang Chen ◽  
Maria Forsyth ◽  
Robert Kerr ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Energy Density ◽  
Electrochemical Impedance ◽  
Cell Formation ◽  
Lithium Ion ◽  
High Energy ◽  
Liquid Electrolyte ◽  
High Energy Density ◽  
Lithium Metal ◽  
Ionic Liquid Electrolyte

<p>ABSTRACT </p><p>Cell formation of lithium-ion cells impacts the evolution of the solid electrolyte interphase (SEI) and the cell cycle stability. Lithium metal anodes are an important step in the development of high energy density batteries owing to the high theoretical specific capacity of lithium metal. However, most lithium metal battery research has used a conventional lithium-ion formation protocol; this is time consuming, costly and does not account for the different properties of the lithium metal electrode. Here, we have used a recently reported promising phosphonium bis(fluorosulfonyl)imide ionic liquid electrolyte coupled with an NMC622 high areal capacity cathode (>3.5 mAh/cm2) to investigate the effect of cell formation rates. A faster formation protocol comprised of a pulsed 1.25C current decreased the formation time by 56 % and gave a 38 % greater capacity retention after 50 cycles when compared to formation at C/20. Electrochemical impedance spectroscopy measurements showed that the fast formation gave rise to a lower-resistance SEI. Column-like lithium deposits with reduced porous lithium domains between the particles were observed using scanning electron microscope imaging. To underline the excellent performance of these high energy-density cells, a 56 % greater stack specific energy was achieved compared to the analogous graphite-based lithium-ion cell chemistries. </p>

Transport Anomalies Emerging from Strong Correlation in Ionic Liquid Electrolytes

2019 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Nathan Craig ◽  
Jake Christensen ◽  
Boris Kozinsky
Keyword(s):  
Ionic Liquid ◽  
Species Interactions ◽  
Clustering Algorithm ◽  
Experimental Studies ◽  
Transference Number ◽  
Liquid Electrolyte ◽  
Total Conductivity ◽  
Single Linkage ◽  
Ionic Liquid Electrolyte ◽  
Dynamics Simulations

<div>Recent works on ionic liquid electrolyte systems motivate the present study of transport regimes where strong species interactions result in significant correlations and deviations from ideal solution behaviour. In order to obtain a complete description of transport in these systems we use rigorous concentrated solution theory coupled with molecular dynamics simulations, beyond the commonly used uncorrelated Nernst-Einstein equation. As a case study, we investigate the NaFSI - Pyr<sub>13</sub>\FSI room temperature ionic liquid electrolyte. When fully accounting for intra- and inter-species correlation, an anomalously low and even negative transference number emerges for NaFSI molar fractions lower than 0.2, emphasising that strong ion-ion coupling in the electrolyte can significantly impact the rate performance of the cell. With increasing concentration the transference number monotonically increases, approaching unity, while the total conductivity decreases as the system transitions to a state resembling a single-ion solid-state electrolyte. The degree of spatial ionic association is explored further by employing a variant of unsupervised single-linkage clustering algorithm. Using this combination of numerical techniques we examine the microscopic mechanisms responsible for the trade-off between key electrolyte transport properties, previously overlooked in both computational and experimental studies.</div>

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