离子相关性和多电解质溶液中的负转移.
Helen K Bergstrom1,2, Kara D Fong1,2, David M Halat1,3
1Department of Chemical & Biomolecular Engineering, University of California Berkeley CA 94720 USA helen_bergstrom@berkeley.edu bmcclosk@berkeley.edu.
Chemical science
|June 23, 2023
概括
短链多电解质溶液由于离子相关性而降低导电性和转移数,这挑战了它们作为高性能电池电解质的使用.
科学领域:
- 电化学 电化学 电化学
- 聚合物科学 聚合物科学
- 材料科学 材料科学 材料科学
背景情况:
- 聚电解质溶液 (PESs) 在高导电性和转移数 (t+) 方面进行了探索.
- PES的目的是通过通过聚合物骨干固来减缓离子运动来增加t+.
- 增加离子电荷可以抵消这种效应,减少t+.
研究的目的:
- 在非水性PES模型中直接测量离子运动.
- 调查影响导电性和t + 的竞争效应.
- 确定短链PES作为高转移数电解质的可行性.
主要方法:
- 电泳核磁共振光谱 (eNMR) 用于测量离子流动性.
- 在电场中直接测量离子运动.
- 计算 Onsager 的运输系数.
主要成果:
- 在纠极限以下,导电性和t+随着聚合物的聚合度的增加而下降.
- 观察到Li+在具有≥10重复单位的多离子中以电场 (负转移数) 的相反方向移动.
- t+随着Li+度的增加而增加.
- 阴离子-阴离子和阴离子-阴离子相关性降低了非纠的PES中的t+.
结论:
- 短链多电解质溶液对于高转移数电解质是不可行的.
- 离子相关性显著影响电解质性能.
- 了解离子相关性对于设计用于电池的先进电解质至关重要.
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