Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland.
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2013 Nov 27;111(22):225703. doi: 10.1103/PhysRevLett.111.225703. Epub 2013 Nov 26.
In this Letter we report the relation between ionic conductivity and structural relaxation in supercooled protic ionic liquids (PILs) under high pressure. The results of high-pressure dielectric and volumetric measurements, combined with rheological and temperature-modulated differential scanning calorimetry experiments, have revealed a fundamental difference between the conducting properties under isothermal and isobaric conditions for three PILs with different charge transport mechanisms (Grotthuss vs vehicle). Our findings indicate a breakdown of the fractional Stokes-Einstein relation and Walden rule when the ionic transport is controlled by fast proton hopping. Consequently, we demonstrate that the studied PILs exhibit significantly higher conductivity than one would expect taking into account that they are in fact a mixture of ionic and neutral species. Thus, the examined herein samples represent a new class of "superionic" materials desired for many advanced applications.
在这封信件中，我们报告了在高压下过冷质子离子液体（PILs）中离子电导率与结构弛豫之间的关系。高压介电和体积测量的结果，结合流变学和温度调制差示扫描量热法实验，揭示了三种具有不同电荷输运机制（Grotthuss 与载体）的 PILs 在等温与等压条件下的电导性质之间存在根本差异。我们的发现表明，当离子输运由快速质子跳跃控制时，分数斯托克斯-爱因斯坦关系和瓦尔登法则失效。因此，我们证明，所研究的 PILs 表现出比仅考虑它们实际上是离子和中性物质混合物时更高的电导率。因此，本文中研究的样品代表了一类新的“超离子”材料，它们适用于许多先进应用。
