Non-solvating, side-chain polymer electrolytes as lithium single-ion conductors: synthesis and ion transport characterization
Non-solvating, side-chain polymer electrolytes as lithium single-ion conductors: synthesis and ion transport characterization
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DOI：
10.1039/c9py01035a
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发表时间：
2020-01-14
影响因子：
4.6
通讯作者：
Schaefer, Jennifer L.
中科院分区：
文献类型：
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作者：
Liu, Jiacheng;Pickett, Phillip D.;Schaefer, Jennifer L.
固态单离子导电聚合物电解质由于其具有高电化学稳定性和安全性的潜力而引起了二次锂电池的极大兴趣，但其低离子电导率限制了其应用。具体而言，聚（环氧乙烷）（PEO）为基础的电解质具有最高的报告Li+电导率为这些材料;然而，它们的潜力是有限的，由于离子传输机制耦合到阳离子溶剂化聚合物链的链段松弛。为了研究缺乏极性基质的单离子导电聚合物电解质的潜力，我们合成了三种基于对聚亚苯基的侧链聚合物电解质，其具有各种侧链阴离子化学（-SO 3-、-PSI-和-TFSI-），这些侧链阴离子化学对Li+具有不同的结合亲和力。与先前报道的锂聚（4-苯乙烯磺酰基（三氟甲基磺酰基）酰亚胺）（LiPSTFSI）相比，侧链聚合物显示出至少3个数量级的高电导率（在150 ℃下，6.7 × 10（-6）S cm（-1）与1.2 × 10（-10）S cm（-1）相比）。通过介电谱分析，我们发现侧链电解质表现出介电弛豫主导的输运机制。电导率高度依赖于侧链阴离子的电荷离域和尺寸，这为电化学应用的聚合物离子导体的工程化提供了一条前进的途径。
Solid-state single-ion conducting polymer electrolytes have drawn considerable interest for secondary lithium batteries due to their potential for high electrochemical stability and safety, but applications are limited by their low ionic conductivities. Specifically, poly(ethylene oxide) (PEO) based electrolytes have the highest reported Li+ conductivities for these materials; however, their potential is limited due to the ion transport mechanism being coupled to segmental relaxations of the cation solvating polymer chain. To investigate the potential of single-ion conducting polymer electrolytes lacking polar matrices, we synthesized three para-polyphenylene-based, side-chain polymer electrolytes with various pendent anion chemistries (-SO3-, -PSI-, and -TFSI-) with differing binding affinities to Li+. Compared with the previously reported lithium poly(4-styrenesulfonyl(trifluoromethylsulfonyl)imide) (LiPSTFSI), the side-chain polymers showed at least 3 orders of magnitude higher conductivity with the same -TFSI- anion (6.7 x 10(-6) S cm(-1) compared with 1.2 x 10(-10) S cm(-1) at 150 degrees C). We found that the side-chain electrolyte showed a dielectric relaxation dominated transport mechanism through use of dielectric spectroscopy analysis. The conductivity is highly dependent on the charge delocalization and size of the pendent anion, which provides a pathway forward for the engineering of polymeric ion conductors for electrochemical applications.