Exploring the Underlying Correlation between the Structure and Ionic Conductivity in Halide Spinel Solid-State Electrolytes with Neutron Diffraction
Jiangyang Pan, Lei Gao, Xinyu Zhang, Dubin Huang, Jinlong Zhu, Liping Wang, Yadong Wei, Wen‐Jin Yin, Yuanguang Xia, Ruqiang Zou, Yusheng Zhao, Songbai Han
Abstract
The development of cutting-edge solid-state electrolytes (SSEs) entails a deep understanding of the underlying correlation between the structure and ionic conductivity. Generally, the structure of SSEs encompasses several interconnected crystal parameters, and their collective influence on Li + transport can be challenging to discern. Here, we systematically investigate the structure–function relationship of halide spinel Li x MgCl 2+ x (2 ≥ x ≥ 1) SSEs. A nonmonotonic trend in the ionic conductivity of Li x MgCl 2+ x SSEs has been observed, with the maximum value of 8.69 × 10 –6 S cm –1 achieved at x = 1.4. The Rietveld refinement analysis, based on neutron diffraction data, has revealed that the crystal parameters including cell parameters, Li + vacancies, Debye–Waller factor, and Li–Cl bond length assume diverse roles in influencing ionic conductivity of Li x MgCl 2+ x at different stages within the range of x values. Besides, mechanistic analysis demonstrates Li + transport along three-dimensional pathways, which primarily governs the contribution to ionic conductivity of Li x MgCl 2+ x SSEs. This study has shed light on the collective influence of crystal parameters on Li + transport behaviors, providing valuable insights into the intricate relationship between the structure and ionic conductivity of SSEs.