Lithium (Li) oxyhalides have emerged as promising solid electrolyte candidates for all-solid-state batteries (ASSBs) due to their superior ionic conductivity and excellent cathode capability. However, the mechanism of Li transport in oxyhalides has remained unclear due to the complex nature of these compounds, which often comprise multiple phases such as crystalline and amorphous structures. Herein, a first-principles study using density functional theory and ab initio molecular dynamic simulation is performed to gain a theoretical insight into the structural behavior and conduction pathway in oxyhalide electrolytes. Li_2.5ZrCl_5.5O_0.5 electrolyte, as a case of study, is comprehensively investigated by considering various phases. It’s revealed that the \({\rm{P}}\bar{3}{\rm{m}}1\) phase is energetically more stable and exhibits one order of magnitude higher Li conductivity compared to the C2/m phase among potential crystalline phases (1.63 mS cm⁻¹ versus 0.24 mS cm⁻¹ at room temperature). Interestingly, an amorphous phase with even higher ionic conductivity (~40 mS cm⁻¹) can be generated by creating LiCl-deficient Li-Zr-O-Cl compounds. The remarkably high ionic conductivity suggests that the amorphous structure is likely the dominant conducting pathway, facilitating fast Li transport due the weak bonding between Li and other atoms. Cl anion mobility is also observed in the amorphous phase through mean square displacement (MSD) calculation, although further analyses revealed this to be localized vibration. This study sheds light on the nature of oxychloride structures and promotes a deeper understanding of the superionic conduction mechanism in oxychlorides, which will contribute to the development of advanced solid electrolytes and ASSBs.

由于其优异的离子电导率和优异的阴极性能，锂（Li）卤氧化物已成为全固态电池（ASSB）有前途的固体电解质候选者。然而，由于这些化合物性质复杂，通常包含晶体和非晶结构等多相，因此锂在卤氧化物中的传输机制仍不清楚。在此，利用密度泛函理论和从头算分子动力学模拟进行第一性原理研究，以获得对卤氧化物电解质的结构行为和传导途径的理论见解。 Li _2.5 ZrCl _5.5 O _0.5 电解质作为研究案例，通过考虑各个相进行了全面研究。结果表明，与 C2/m 相相比，\({\rm{P}}\bar{3}{\rm{m}}1\) 相在能量上更加稳定，并且表现出高一个数量级的 Li 电导率潜在结晶相（室温下为 1.63 mS cm ⁻¹ 对比 0.24 mS cm ⁻¹ ）。有趣的是，通过创建缺乏 LiCl 的 Li-Zr-O-Cl 化合物，可以生成具有更高离子电导率（~40 mS cm ⁻¹ ）的非晶相。非常高的离子电导率表明，非晶结构可能是主要的传导途径，由于Li与其他原子之间的弱键合，促进了Li的快速传输。通过均方位移 (MSD) 计算，也在非晶相中观察到 Cl 阴离子迁移率，尽管进一步的分析表明这是局部振动。 这项研究揭示了氯氧化物结构的性质，促进了对氯氧化物中超离子传导机制的更深入理解，这将有助于先进固体电解质和ASSB的发展。