Ariga Kotoko, Akakabe Shuho, Sekiguchi Ryotaro, Thomas Morgan L, Takeoka Yuko, Rikukawa Masahiro, Yoshizawa-Fujita Masahiro
Department of Materials and Life Sciences, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan.
ACS Omega. 2024 May 9;9(20):22203-22212. doi: 10.1021/acsomega.4c01137. eCollection 2024 May 21.
Organic ionic plastic crystals (OIPCs) have attracted attention as novel organic solid electrolyte materials, but their insufficient mechanical strength and ionic conductivity have prevented their application. In this study, a lithium salt, lithium bis(fluorosulfonyl)amide (LiFSA), and an inorganic solid electrolyte, LiLaZrO (LLZO), were added to an OIPC, ,-diethylpyrrolidinium bis(fluorosulfonyl)amide ([Cepyr][FSA]). The fabricated organic-inorganic hybrid solid electrolytes were evaluated thermally, mechanically, and electrochemically to reveal which factors affect the properties of the electrolytes. All samples showed excellent thermal stability regardless of LiFSA or LLZO concentration, and they were found to be highly plastic and ion-conductive solids at a wide range of temperatures. It was also revealed that the addition of LLZO raised the nanoindentation stiffness () of the [Cepyr][FSA]/LiFSA composites. The ionic conductivity of the hybrid electrolytes was higher than that of the pristine OIPC, reaching a value of 2.1 × 10 S cm at 25 °C upon addition of appropriate amounts of LiFSA and LLZO. Overall, samples with higher LiFSA concentration and moderate LLZO concentration exhibited higher ionic conductivity. Cyclic voltammetry results showed that the [Cepyr][FSA]/LiFSA/LLZO composites were lithium-ion conductors. These findings indicate that by optimizing the concentrations of lithium salt and LLZO, it would be possible to realize their applications as solid electrolytes.
有机离子塑性晶体（OIPCs）作为新型有机固体电解质材料已引起关注，但其机械强度和离子电导率不足阻碍了其应用。在本研究中，将锂盐双（氟磺酰）亚胺锂（LiFSA）和无机固体电解质LiLaZrO（LLZO）添加到OIPC，即1,2 - 二乙基吡咯烷鎓双（氟磺酰）亚胺（[Cepyr][FSA]）中。对制备的有机 - 无机混合固体电解质进行了热学、力学和电化学评估，以揭示哪些因素影响电解质的性能。所有样品无论LiFSA或LLZO浓度如何均表现出优异的热稳定性，并且发现在很宽的温度范围内它们都是高塑性和离子导电的固体。还发现添加LLZO提高了[Cepyr][FSA]/LiFSA复合材料的纳米压痕硬度（）。混合电解质的离子电导率高于原始OIPC，在添加适量的LiFSA和LLZO后，在25℃时达到2.1×10 S cm的值。总体而言，LiFSA浓度较高且LLZO浓度适中的样品表现出较高的离子电导率。循环伏安法结果表明[Cepyr][FSA]/LiFSA/LLZO复合材料是锂离子导体。这些发现表明，通过优化锂盐和LLZO的浓度，有可能实现它们作为固体电解质的应用。
