Yahata Yoshikazu, Marukane Shoko, Sato Takaya, Tsujii Yoshinobu, Ohno Kohji
Institute for Chemical Research , Kyoto University , Gokasho, Uji , Kyoto 611-0011 , Japan.
Department of Material Engineering , Tsuruoka National College of Technology , 104 Sawada , Inooka , Tsuruoka 997-8511 , Japan.
Langmuir. 2019 Nov 12;35(45):14566-14575. doi: 10.1021/acs.langmuir.9b02573. Epub 2019 Oct 29.
The development of quasi-solid electrolytes for electrical devices operating at high voltages is important for addressing future energy storage requirements. Here, we report a new method to fabricate quasi-solid electrolytes through the thermally induced phase separation of a polymer/ionic liquid (polymer/IL) blend. In a polymer/IL blend that exhibits lower critical solution temperature-type phase separation, we demonstrate that the addition of silica particles decorated with concentrated polymer brushes (CPB-SiPs) can prevent macroscopic phase separation after heating, resulting in a quasi-solid electrolyte with a continuous IL phase. This is due to the adsorption of CPB-SiPs onto the polymer/IL interface in the phase-separated structure. We also reveal a relationship between the molecular weight of the CPB and the phase-separated structure. Namely, a quasi-solid film with a bicontinuous phase-separated structure is formed only when polymers with an appropriate molecular weight are grafted on the CPB-SiPs. The resulting quasi-solid film exhibits a relatively high ionic conductivity, owing to the existence of a continuous ion-conductive phase solely consisting of IL. In addition, we fabricated a quasi-solid electrolyte with the blended film and successfully applied it to an electric double-layer capacitor operating at a high voltage, owing to the wider potential window of the IL employed herein.
开发用于高压运行电气设备的准固态电解质对于满足未来储能需求至关重要。在此，我们报告了一种通过聚合物/离子液体（聚合物/IL）共混物的热致相分离来制备准固态电解质的新方法。在表现出较低临界溶液温度型相分离的聚合物/IL共混物中，我们证明添加用浓缩聚合物刷修饰的二氧化硅颗粒（CPB-SiP）可以防止加热后宏观相分离，从而得到具有连续IL相的准固态电解质。这是由于CPB-SiP在相分离结构中吸附到聚合物/IL界面上。我们还揭示了CPB的分子量与相分离结构之间的关系。也就是说，只有当具有适当分子量的聚合物接枝到CPB-SiP上时，才会形成具有双连续相分离结构的准固态膜。由于仅由IL组成的连续离子导电相的存在，所得准固态膜表现出相对较高的离子电导率。此外，我们用该共混膜制备了准固态电解质，并成功地将其应用于在高压下运行的双电层电容器，这是因为本文所用IL具有更宽的电位窗口。
