揭示碘化银掺杂磷酸银玻璃中离子传导的起源
Revealing the origin of ionic conduction in silver-iodide-doped silver phosphate glass
- University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
通过太赫兹光谱研究碘化银掺杂磷酸银玻璃，揭示离子传导源于束缚极化嵌入软基质并伴随高载流子密度，实现从振动束缚到短程色散输运的转变。
AI中文摘要：
快速离子输运是许多固态电解质的标志性特征，但其微观起源尚未完全理解。在缺乏微观洞察的情况下，下一代固态电池的开发在很大程度上仍停留在经验层面。大多数现有测量要么访问低频输运响应，要么访问高频束缚极化，而中间介观频率区间正是离子输运出现的区域。通过改变$\mathrm{AgI}$浓度（$x$）并在原型玻璃态电解质$\left(\mathrm{AgI}\right)_{x}\left(\mathrm{AgPO_3}\right)_{(1-x)}$中进行时域太赫兹光谱（TDTS）测量，我们揭示了这一中间频率区间，并识别出从束缚电流主导的传导到源于短程色散离子输运的电导率的交叉。我们发现，与$\mathrm{P{-}O^- -Ag^+}$基团的键弯曲运动相关的束缚极化在所有组分中都存在，但单独不足以产生离子输运。只有当这种极化嵌入足够柔软的$\mathrm{AgPO_3}$玻璃态基质中并伴随高载流子密度时，输运才会出现。这些因素共同将系统从振动束缚响应转变为短程色散运动。
英文摘要：
Fast ionic transport is a defining feature of many solid electrolytes, yet its microscopic origin is not fully understood. In the absence of microscopic insights, the development of next-generation solid-state batteries remains largely empirical. Most existing measurements access either the low-frequency transport response or the high-frequency bound polarization, yet the intermediate mesoscopic frequency regime is where ionic transport emerges. By varying the $\mathrm{AgI}$ concentration ($x$) and performing time-domain terahertz spectroscopy (TDTS) in a prototypical glassy electrolyte $\left(\mathrm{AgI}\right)_{x}\left(\mathrm{AgPO_3}\right)_{(1-x)}$, we reveal this intermediate frequency regime and identify a crossover from bound-current-dominated conduction to conductivity arising from short-range dispersive ionic transport. We find that bound polarization associated with the bond-bending motion of the $\mathrm{P{-}O^- -Ag^+}$ motif is present across compositions but is insufficient to produce ionic transport on its own. Transport emerges only when this polarization is embedded in a sufficiently soft $\mathrm{AgPO_3}$ glassy matrix and accompanied by a high carrier density. These ingredients together take the system from a vibrationally bound response to short-range dispersive motion.
