Liu Zhantao, Chien Po-Hsiu, Wang Shuo, Song Shaowei, Lu Mu, Chen Shuo, Xia Shuman, Liu Jue, Mo Yifei, Chen Hailong
George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
Nat Chem. 2024 Oct;16(10):1584-1591. doi: 10.1038/s41557-024-01634-6. Epub 2024 Sep 23.
Halides of the family LiMX (M = Y, In, Sc and so on, X = halogen) are emerging solid electrolyte materials for all-solid-state Li-ion batteries. They show greater chemical stability and wider electrochemical stability windows than existing sulfide solid electrolytes, but have lower room-temperature ionic conductivities. Here we report the discovery that the superionic transition in LiYCl is triggered by the collective motion of anions, as evidenced by synchrotron X-ray and neutron scattering characterizations and ab initio molecular dynamics simulations. Based on this finding, we used a rational design strategy to lower the transition temperature and thus improve the room-temperature ionic conductivity of this family of compounds. We accordingly synthesized LiYClBr and LiGdClBr and achieved very high room-temperature conductivities of 6.1 and 11 mS cm for LiYClBr and LiGdClBr, respectively. These findings open new routes to the design of room-temperature superionic conductors for high-performance solid batteries.
LiMX（M = Y、In、Sc等，X = 卤素）家族的卤化物是新兴的用于全固态锂离子电池的固体电解质材料。它们比现有的硫化物固体电解质表现出更高的化学稳定性和更宽的电化学稳定窗口，但室温离子电导率较低。在此，我们报告一项发现，即LiYCl中的超离子转变是由阴离子的集体运动引发的，同步加速器X射线和中子散射表征以及从头算分子动力学模拟证明了这一点。基于这一发现，我们采用了合理的设计策略来降低转变温度，从而提高该类化合物的室温离子电导率。我们据此合成了LiYClBr和LiGdClBr，LiYClBr和LiGdClBr的室温电导率分别达到了6.1和11 mS cm，非常高。这些发现为高性能固体电池的室温超离子导体设计开辟了新途径。
