Ionic interactions control the modulus and mechanical properties of molecular ionic composite electrolytes
Ionic interactions control the modulus and mechanical properties of molecular ionic composite electrolytes
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DOI：
10.1039/d1tc04119c
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发表时间：
2021-11-22
影响因子：
6.4
通讯作者：
Colby, Ralph H.
中科院分区：
文献类型：
--
作者：
Bostwick, Joshua E.;Zanelotti, Curt J.;Colby, Ralph H.
分子离子复合材料（MIC）是一类新型固体电解质，结合了离子液体（IL）和硬棒双螺旋聚电解质聚（2,2'-二磺酰基-4,4'联苯胺对苯二甲酰胺）（PBDT）。在本研究中，我们重点研究具有固定 PBDT 重量百分比 (10 wt%) 和不同 IL 化学和分子体积 (V-m) 的 MIC 的机械、介电和离子扩散动力学。所有六种 MIC 在 30 摄氏度下均产生 50-500 MPa 范围内的拉伸模量，比相同 MIC 的剪切模量高出 60 倍。高范围的模量和拉伸剪切模量比强调了 PBDT 链的分布以及 IL 离子和 PBDT 链之间的强离子相互作用决定了 MIC 中的模量和机械强度。此外，这些 MIC 在 30 摄氏度下表现出 1-6 mS cm(-1) 的高离子电导率，与测量的 IL 离子扩散系数一致。 MIC 电解质非凡的机械性能和高离子电导率的可调性极大地激发了它们在先进电化学设备中的应用。
Molecular ionic composites (MICs) are a new class of solid electrolytes that combine ionic liquids (ILs) and a rigid-rod double helical polyelectrolyte, poly(2,2 '-disulfonyl-4,4 ' benzidine terephthalamide) (PBDT). In this study, we focus on the mechanical, dielectric, and ion diffusive dynamics of MICs with a fixed PBDT weight percent (10 wt%) and varying IL chemistry and molecular volume (V-m). All six MICs produce tensile moduli in the range of 50-500 MPa at 30 degrees C, up to 60x higher than the shear moduli of the same MICs. The high range of moduli and tensile to shear modulus ratio emphasizes that the distribution of PBDT chains and the strong ionic interactions between IL ions and PBDT chains dictate the modulus and the mechanical strength in MICs. Additionally, these MICs exhibit high ionic conductivities ranging from 1-6 mS cm(-1) at 30 degrees C, consistent with the measured diffusion coefficients of the IL ions. The tunability of the extraordinary mechanical properties and high ionic conductivities of MIC electrolytes greatly inspire their use in advanced electrochemical devices.