AI 中文总结
本研究结合MD-拉曼方法计算LLZO不同相及Ta掺杂变体的拉曼光谱，揭示其拉曼特征与锂离子动力学的原子级关联，为拉曼光谱用于探测锂石榴石电解质的锂离子动力学提供了微观依据。
AI 中文摘要
锂镧锆酸盐（LLZO）石榴石因具有高离子电导率、化学稳定性及与锂金属的兼容性，成为下一代电池最具潜力的固体电解质之一。拉曼光谱常用于区分LLZO高电导率的立方相与低电导率的四方相，但这些光谱差异的原子起源及其与锂离子输运的直接关联仍未明确。本研究通过对比计算与实验的拉曼光谱（涉及LLZO的四方相、立方相及Ta掺杂变体）填补了这一空白，其中计算光谱来自MD-拉曼方法，该方法将机器学习分子动力学与第一性原理极化率计算相结合。研究表明，不同LLZO变体间截然不同的离子输运行为编码于锂亚晶格的振动动力学中，并在其拉曼光谱中产生 distinct 特征。对称分辨分析进一步揭示，实验观测到的拉曼峰并非对应单个简正模式，而是源自多个对称允许振动的重叠贡献，这对传统的峰归属方法提出了挑战。通过将实验可及的拉曼特征与潜在的原子级动力学明确关联，本研究结果表明拉曼光谱可超越经验性的物相识别，成为探测锂石榴石电解质中锂离子动力学的微观工具。
英文摘要
Lithium lanthanum zirconate (LLZO) garnets are among the most promising solid electrolytes for next-generation batteries owing to their high ionic conductivity, chemical stability, and compatibility with lithium metal. Raman spectroscopy is commonly employed to distinguish the highly conductive cubic phase from the poorly conductive tetragonal phase of LLZO, yet the atomistic origin of these spectral differences and their direct connection to Li-ion transport remain unresolved. Here, we close this gap by comparing computed and experimental Raman spectra for the tetragonal, cubic, and Ta-doped variants of LLZO, with the computed spectra obtained from the MD-Raman approach that combines machine-learning molecular dynamics with first-principles polarizability calculations. We show that the contrasting ionic transport behavior across these LLZO variants is encoded in the vibrational dynamics of the lithium sublattice and gives rise to distinct features in their Raman spectra. A symmetry-resolved analysis further reveals that experimentally observed Raman peaks do not correspond to individual normal modes, but instead arise from overlapping contributions of multiple symmetry-allowed vibrations, challenging conventional peak-assignment approaches. By explicitly connecting experimentally accessible Raman signatures to the underlying atomic-scale dynamics, our results show how Raman spectroscopy can move beyond empirical phase identification toward a microscopic probe of Li-ion dynamics in lithium garnet electrolytes.
