Machine learning molecular dynamics simulation identifying weakly negative effect of polyanion rotation on Li-ion migration  

作　　者：Zhenming Xu Huiyu Duan Zhi Dou Mingbo Zheng Yixi Lin Yinghui Xia Haitao Zhao Yongyao Xia 

机构地区：[1]College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,210016 Nanjing,China [2]Center for Intelligent and Biomimetic Systems,Shenzhen Institutes of Advanced Technology(SIAT),Chinese Academy of Sciences(CAS),518055 Shenzhen,China [3]Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Institute of New Energy,iChEm(Collaborative Innovation Center of Chemistry for Energy Materials),Fudan University,200433 Shanghai,China

出　　处：《npj Computational Materials》2023年第1期1276-1286,共11页计算材料学（英文）

基　　金：This work is supported by the Young Scientists Fund of the National Natural Science Foundation of China(22209074);the Fundamental Research Funds for the Central Universities(NO.NS2022059,NO.NS2021039);the Talent Research Startup Funds of Nanjing University of Aeronautics and Astronautics,the Jiangsu Funding Program for Excellent Postdoctoral Talent,and the Selected Funding for Scientific and Technological Innovation Projects for Overseas Students in Nanjing;This work is partially supported by High Performance Computing Platform of Nanjing University of Aeronautics and Astronautics.

摘　　要：Understanding the physical picture of Li ion transport in the current ionic conductors is quite essential to further develop lithium superionic conductors for solid-state batteries.The traditional practice of directly extrapolating room temperature ion diffusion properties from the high-temperature(>600 K)ab initio molecular dynamics simulations(AIMD)simulations by the Arrhenius assumption unavoidably cause some deviations.Fortunately,the ultralong-time molecular dynamics simulation based on the machine-learning interatomic potentials(MLMD)is a more suitable tool to probe into ion diffusion events at low temperatures and simultaneously keeps the accuracy at the density functional theory level.Herein,by the low-temperature MLMD simulations,the non-linear Arrhenius behavior of Li ion was found for Li3ErCl6,which is the main reason for the traditional AIMD simulation overestimating its ionic conductivity.The 1μs MLMD simulations capture polyanion rotation events in Li_(7)P_(3)S_(11) at room temperature,in which four[PS_(4)]^(3−)tetrahedra belonging to a part of the longer-chain[P_(2)S_(7)]4−group are noticed with remarkable rotational motions,while the isolated group[PS_(4)]^(3−)does not rotate.However,no polyanion rotation is observed in Li10GeP_(2)S12,β-Li3PS_(4),Li3ErCl6,and Li3YBr6 at 300 K during 1μs simulation time.Additionally,the ultralong-time MLMD simulations demonstrate that not only there is no paddle-wheel effect in the crystalline Li_(7)P_(3)S_(11) at room temperature,but also the rotational[PS_(4)]^(3−)polyanion groups have weakly negative impacts on the overall Li ion diffusion.The ultralong-time MLMD simulations deepen our understanding of the relationship between the polyanion rotation and cation diffusion in ionic conductors at room environments.

关 键 词：ROTATION dynamics effect 

分 类 号：O561[理学—原子与分子物理]