arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2102.08413cond-mat.mtrl-sci
收藏

弥合锂超离子导体中模拟和实验离子电导率之间的差距

Bridging the Gap Between Simulated and Experimental Ionic Conductivities in Lithium Superionic Conductors

Ji Qi, Swastika Banerjee, Yunxing Zuo, Chi Chen, Zhuoying Zhu, H. C. Manas Likhit, Xiangguo Li, Shyue Ping Ong

摘要:

锂超离子导体(LSC)作为下一代全固态锂离子电池的固体电解质是非常重要的。虽然$ab$ $initio$分子动力学已被广泛应用于研究这些材料,但由于这种模拟的高温和短时间尺度,预测和实验测量的离子电导率和活化能之间往往存在很大的差异。在这里,我们提出了一个战略,以弥补这一差距,使用矩张量势(MTP)。我们表明,使用范德华optB 88功能计算的能量和力训练的MTP产生更准确的晶格参数,这反过来又导致准确预测的离子电导率和活化能的锂$_{0.33}$ La $_{0.56}$ TiO $_3$,锂$_3$ YCl $_6$和锂$_7$ P $_3$ S $_{11}$ LSC。使用optB88 MTP的NPT MD模拟还显示,所有三个LSC在相对较低的温度下在两个准线性Arrhenius制度之间发生转变。这种转变可以追溯到扩散途径的数量和多样性的扩张,在某些情况下,扩散的维度发生了变化。这项工作不仅提出了一种方法来开发高精度的MTP,但也概述了LSC的扩散特性,否则无法通过$ab$ $initio$计算。

英文摘要:

Lithium superionic conductors (LSCs) are of major importance as solid electrolytes for next-generation all-solid-state lithium-ion batteries. While $ab$ $initio$ molecular dynamics have been extensively applied to study these materials, there are often large discrepancies between predicted and experimentally measured ionic conductivities and activation energies due to the high temperatures and short time scales of such simulations. Here, we present a strategy to bridge this gap using moment tensor potentials (MTPs). We show that MTPs trained on energies and forces computed using the van der Waals optB88 functional yield much more accurate lattice parameters, which in turn leads to accurate prediction of ionic conductivities and activation energies for the Li$_{0.33}$La$_{0.56}$TiO$_3$, Li$_3$YCl$_6$ and Li$_7$P$_3$S$_{11}$ LSCs. NPT MD simulations using the optB88 MTPs also reveal that all three LSCs undergo a transition between two quasi-linear Arrhenius regimes at relatively low temperatures. This transition can be traced to an expansion in the number and diversity of diffusion pathways, in some cases with a change in the dimensionality of diffusion. This work presents not only an approach to develop high accuracy MTPs, but also outlines the diffusion characteristics for LSCs which is otherwise inaccessible through $ab$ $initio$ computation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑