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Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications
Published on: August 12, 2013
Anionic Effects on Lithium-Ion Transport in Highly Concentrated Lithium Salt/Propylene Carbonate Solutions
Ryoichi Tatara1,2, Kousuke Takeshita1, Jiyoung Ock1
1Department of Chemistry and Life Science, Yokohama National University, Yokohama, Japan.
Summary
Anion basicity in highly concentrated electrolytes (HCEs) dictates lithium-ion transport. Stronger Lewis base anions increase lithium-ion transference but decrease conductivity, revealing a critical tradeoff.
Area of Science:
- Electrochemistry
- Materials Science
- Physical Chemistry
Background:
- Highly concentrated electrolytes (HCEs) display unique ion transport distinct from conventional electrolytes.
- The influence of anion species on lithium-ion (Li+) transport in HCEs is not well understood.
Purpose of the Study:
- To systematically investigate the role of anion Lewis basicity in governing Li+ transport properties in LiX/PC mixtures.
- To correlate macroscopic transport properties with molecular-scale structures.
Main Methods:
- Evaluated ionic conductivity, viscosity, self-diffusion coefficients, and Li+ transference numbers.
- Employed molecular dynamics simulations to obtain molecular-scale structural insights.
- Varied anion species (PF6-, N(SO2F)2-, N(SO2CF3)2-, ClO4-, BF4-, TfO-) in LiX/PC mixtures.
Main Results:
- Weak Lewis base anions led to high ionic conductivity and coupled Li+-solvent diffusion.
- Strong Lewis base anions promoted ion-pair formation, structural Li+ diffusion, and high transference numbers.
- Li+ transference numbers increased with anion Lewis basicity and concentration, while conductivity decreased.
Conclusions:
- Anion Lewis basicity is a critical factor governing ion association and correlated motion in HCEs.
- Anion basicity dictates Li+ transport mechanisms, highlighting an intrinsic tradeoff between conductivity and transference numbers.
Keywords:
Lewis basehighly concentrated electrolytelithium‐ion transportpropylene carbonatetransference numberMore Related Videos
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