Li2S-P2S5 系统的新通用力场,Physical Chemistry Chemical Physics

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Li2S-P2S5 系统的新通用力场
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2022-01-07 , DOI: 10.1039/d1cp05393k
Shunsuke Ariga ₁ , Takahiro Ohkubo ₁ , Shingo Urata ₂ , Yutaka Imamura ₂ , Taketoshi Taniguchi ₂

Affiliation

硫代磷酸锂电解液是一种很有前途的全固态电池材料。从头算分子动力学 (AIMD) 模拟已用于研究单晶和玻璃态化合物中的离子传导机制。然而，真实材料（例如，具有晶界和多相玻璃陶瓷的材料）的复杂性导致 AIMD 模拟具有高计算成本。为了克服这一计算限制，我们为锂固态电解质的经典分子动力学 (CMD) 模拟开发了一种新的原子间势。训练数据集由具有代表性的硫化物电解质（β-Li ₃ PS ₄、γ-Li ₃ PS ₄、Li ₄ P ₂ S ₆、Li ₇ P ₃ S ₁₁和 Li ₇ PS ₆晶体和 70Li ₂ S-30P ₂ S ₅玻璃）。使用 II 类和 Stillinger-Weber 势的函数形式，通过最小化 CMD 和 AIMD 结果之间的原子力、应力和势能差异来优化所有参数。随后的验证表明，优化后的参数可以再现 Li ⁺的动力学以及结晶和玻璃材料的结构。_{Li 7} P ₃ S的离子电导率₁₁晶体大约是等化学计量 70Li₂ S–30P₂ S₅玻璃的 5 倍，表明使用开发的力场的 CMD 模拟准确地再现了AIMD_{中 Li 7} P₃ S_{11中的有效传导路径。}开发的力场参数可以在 CMD 框架中模拟复杂材料，包括非晶-晶体界面和多相玻璃陶瓷。

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A new universal force-field for the Li2S–P2S5 system

Lithium thiophosphate electrolyte is a promising material for application in all-solid-state batteries. Ab initio molecular dynamics (AIMD) simulations have been used to investigate the ion conduction mechanisms in single-crystalline and glassy compounds. However, the complexity of real materials (e.g., materials with grain boundaries and multiphase glass-ceramics) causes AIMD simulations to have high computational cost. To overcome this computational limitation, we developed a new interatomic potential for classical molecular dynamics (CMD) simulations of Li solid-state electrolytes. The training datasets were generated from representative sulfide electrolytes (β-Li₃PS₄, γ-Li₃PS₄, Li₄P₂S₆, Li₇P₃S₁₁, and Li₇PS₆ crystals and 70Li₂S–30P₂S₅ glass). Using the functional forms of the Class II and Stillinger–Weber potentials, all parameters were optimized by minimizing the differences in forces on atoms, stresses, and potential energies between the CMD and AIMD results. Subsequent validation showed that the optimized parameters can reproduce the dynamics of Li⁺ as well as the structures of the crystalline and glassy materials. The ionic conductivity of Li₇P₃S₁₁ crystal was approximately five times that of the isostoichiometric 70Li₂S–30P₂S₅ glass, indicating that CMD simulations using the developed force-field accurately reproduced the effective conduction path in Li₇P₃S₁₁ from AIMD. The developed force-field parameters make it possible to simulate complex materials including amorphous–crystalline interfaces and multiphase glass-ceramics in the CMD framework.

更新日期：2022-01-07

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