北京理工大学苏岳锋团队报道了跳跃速度和迁移熵是固态电解质中导电超离子导体的起源。相关研究成果发表在2023年5月17日出版的《美国化学会杂志》。

无机固态电解质（SSEs）因其在高能固态电池中的潜在应用而备受关注。然而，对SSEs中快速离子传导的潜在机制缺乏了解。

该文中，研究人员通过联合分析方法阐明了影响SSEs中离子电导率的关键参数，该方法检查了几种具有代表性的SSEs（Li₃YCl₆、Li₃HoCl₆和Li₆PS₅Cl），这些SSEs在xLiCl-InCl₃系统中得到了进一步验证。电导率谱的标度分析了移动载流子浓度和跳跃速率对离子电导率的解耦影响。尽管载流子浓度随温度而变化，但仅此变化并不能导致电导率的几个数量级差异。相反，跳跃速率和离子电导率随着温度的变化呈现出相同的趋势。迁移熵是由跳跃原子从初始位置到鞍状位置的晶格振动引起的，也被证明在Li⁺的快速迁移中起着重要作用。

研究结果表明，Li⁺跳跃频率和迁移能等多个因变量也影响SSEs内的离子传导行为。

附：英文原文

Title: Hopping Rate and Migration Entropy as the Origin of Superionic Conduction within Solid-State Electrolytes

Author: Xiaona Li, Honggang Liu, Changtai Zhao, Jung Tae Kim, Jiamin Fu, Xiaoge Hao, Weihan Li, Ruying Li, Ning Chen, Duanyun Cao, Zhenwei Wu, Yuefeng Su, Jianwen Liang, Xueliang Sun

Issue&Volume: May 17, 2023

Abstract: Inorganic solid-state electrolytes (SSEs) have gained significant attention for their potential use in high-energy solid-state batteries. However, there is a lack of understanding of the underlying mechanisms of fast ion conduction in SSEs. Here, we clarify the critical parameters that influence ion conductivity in SSEs through a combined analysis approach that examines several representative SSEs (Li3YCl6, Li3HoCl6, and Li6PS5Cl), which are further verified in the xLiCl-InCl3 system. The scaling analysis on conductivity spectra allowed the decoupled influences of mobile carrier concentration and hopping rate on ionic conductivity. Although the carrier concentration varied with temperature, the change alone cannot lead to the several orders of magnitude difference in conductivity. Instead, the hopping rate and the ionic conductivity present the same trend with the temperature change. Migration entropy, which arises from lattice vibrations of the jumping atoms from the initial sites to the saddle sites, is also proven to play a significant role in fast Li+ migration. The findings suggest that the multiple dependent variables such as the Li+ hopping frequency and migration energy are also responsible for the ionic conduction behavior within SSEs.

DOI: 10.1021/jacs.3c01955

Source: https://pubs.acs.org/doi/10.1021/jacs.3c01955