在以乙烯氧化物为基础的同聚合物和块共聚合物电解质中离子溶解和运输行为的分子水平差异
Daniel Sharon1,2, Peter Bennington1, Michael A Webb3
1Pritzker School of Molecular Engineering, University of Chicago, 5640 S Ellis Ave, Chicago, Illinois 60637, United States.
Journal of the American Chemical Society
|February 22, 2021
概括
区块共聚合物电解质 (BCE) 通过在接口处隔离多余的盐来维持电池的高导电性,与同聚合物类似物不同. 这样可以保持最佳的溶解点,以提高离子传输.
科学领域:
- 材料科学
- 电化学
- 聚合物科学
背景情况:
- 块共聚合物电解质 (BCE) 为电池提供了固态电解质的潜力.
- 与LiTFSI混合的聚乙烯块聚乙烯氧化物 (SEO) 形成具有明显纳米域的机械强电解质.
研究的目的:
- 与PEO-LiTFSI同聚合物相比,基本了解SEO-LiTFSI BCE中的导电性和传输机制.
- 研究盐度对离子溶解,结合,分布和导电性的影响.
主要方法:
- 离子导电性测量
- 福里埃变换红外光谱 (FTIR)
- 拉曼光谱学
- 原子级分子动力学模拟.
主要成果:
- BCE和同聚合物电解质在Li/EO比率为1/12时具有最大导电性.
- 超过1/12,同聚合物导电性显著下降,而BCE导电性保持稳定.
- 在较高盐度下,FTIR和拉曼数据显示了BCE和同聚合物之间的不同离子溶解和结合行为.
结论:
- 由于域界面上的离子分离,BCE在更广泛的盐度范围内保持高导电性.
- 在BCE中,过量的盐被隔离在接口上,在导电纳米领域内保持最佳的溶解点.
- 这种界面盐封存机制是 BCE 作为固态电解质的卓越性能的关键.
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