Conductivity and Morphology Correlations of Ionic-Liquid/Lithium-Salt/Block Copolymer Nanostructured Hybrid Electrolytes
Conductivity and Morphology Correlations of Ionic-Liquid/Lithium-Salt/Block Copolymer Nanostructured Hybrid Electrolytes
复制标题
DOI：
10.1021/acsaem.7b00173
复制
发表时间：
2018-02-01
影响因子：
6.4
通讯作者：
Mueller-Buschbaum, Peter
中科院分区：
文献类型：
--
作者：
Metwalli, Ezzeldin;Kaeppel, Maximilian V.;Mueller-Buschbaum, Peter
固态聚合物电解质膜（PEMs）最艰巨的挑战是实现接近液体电解质的高离子电导率，同时保持增强的热学和机械性能。由二嵌段共聚物（聚苯乙烯-嵌段聚环氧乙烷）组成的PEMs的离子电导率与形貌的关系研究了PSb-PEO、锂盐（三氟甲烷磺酸锂；LiTO）和离子液体（1-乙基-3-甲基咪唑三氟甲烷磺酸盐；EMIMTf）。在室温离子电导率高于1 mS cm（-1）基准的情况下，实现了优化的功能纳米结构PEMs。这些微相分离电解质的形貌主要由柔软的高离子导电性PEO/LiTUIL基质和少量的玻璃状高模量PS纳米畴组成。混合电解质中的离子-液体上传抑制了PEO的结晶，降低了PEO的玻璃化转变温度，促进了PEO链的延伸，并增强了未解离锂盐在PS-PEO畴界面的增溶作用。这些由离子-液体负载引起的固有特性有助于实现稳定和坚固的纳米结构电解质膜，并可以解释实现的基准电导率。
The most daunting challenge in solid-state polymer electrolyte membranes (PEMs) is to achieve high ionic conductivity close to that of the liquid electrolytes, while maintaining enhanced thermal and mechanical performances. The ionic conductivity in relation to the morphology of PEMs composed of diblock copolymer (polystyrene-block-poly(ethylene oxide); PSb-PEO), lithium salt (lithium trifluoromethanesulfonate; LiTO, and ionic liquid (1-ethyl-3-methylimidazolium trifluoromethanesulfonate; EMIMTf) is investigated. The optimized functional nanostructured PEMs are achieved with room-temperature ionic conductivities higher than a 1 mS cm(-1) benchmark. The morphology of these microphase-separated electrolytes is composed of a major soft high ionic-conductive PEO/LiTUIL matrix with minor glassy high-modulus PS nanodomains. The ionic-liquid upload in hybrid electrolytes inhibits the PEO crystallization, reduces the PEO glass transition temperature, promotes an extended PEO chain conformation, and enhances the solubilization of the non-dissociated lithium salt at the PS-PEO domain interfaces. These intrinsic properties caused by the ionic-liquid loading serve to achieve stable and robust nanostructured electrolyte membranes and can explain the achieved benchmark conductivity.