Microphase-separated structures of ion gels consisting of ABA-type block copolymers and an ionic liquid: A key to escape from the trade-off between mechanical and transport properties

POLYMER

卷:206

Article

Mizuno, Haruna¹  Hashimoto, Kei^1,2  Tamate, Ryota^1,3  Kokubo, Hisashi¹  Ueno, Kazuhide¹  Li, Xiang⁴  Watanabe, Masayoshi^1,2 

[1] Yokohama Natl Univ, Dept Chem & Life Sci, Hodogaya Ku, 79-5 Tokiwadai, Yokohama, Kanagawa 2408501, Japan

[2] Yokohama Natl Univ, Inst Adv Sci, Hodogaya Ku, 79-5 Tokiwadai, Yokohama, Kanagawa 2408501, Japan

[3] Natl Inst Mat Sci, Ctr Green Res Energy & Environm Mat, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

[4] Univ Tokyo, Inst Solid State Phys, 5-1-5 Kashiwanoha, Kashiwa, Chiba 2778581, Japan

关键词: Ionic liquid;    Block copolymer;    Microphase separation;    Ionic conductivity;    Mechanical property;    ORCID;   

DOI  :  10.1016/j.polymer.2020.122849

来源: Elsevier

【 摘 要 】

Upon combination of an ionic liquid (IL) with an amphiphilic ABA-type triblock copolymer, the insoluble A blocks aggregate to form mechanical frameworks and the soluble B blocks form ion-transport paths by incorporating the IL. Consequently, a self-standing ion gel, exhibiting the characteristic high ionic conductivity of ILs, can be obtained. In this study, we investigated the effect of microstructures formed by the block copolymer (spherical, cylindrical, gyroid, and lamellar structures) on the ionic conductivity and mechanical properties of the ion gel by focusing on the microstructures. As a result, an ion gel that formed an isotropic bicontinuous structure was successfully obtained via a heat-induced order-order transition. The structure was maintained even at room temperature, and the ion gel having a bicontinuous structure exhibited favorable mechanical properties (storage modulus, G' similar to 1.0 MPa) and good ionic conductivity (sigma similar to 0.1 mS cm(-1)). In contrast, the ion gels having anisotropic structures (cylindrical structure) exhibited weaker mechanical properties and lower ionic conductivity. The characteristics of bicontinuous structures may be the key to resolving the trade-off between mechanical and transport properties of electrolyte materials for electrochemical devices.

【 授权许可】

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