Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Published

April 6, 2022

Author(s)

Elias Sebti, Hayden Evans, Hengning Chen, Peter Richardson, Kelly White, Raynald Giovine, Krishna P. Koirala, Yaobin Xu, Eliovardo Gonzalez-Correa, Chongmin Wang, Craig Brown, Anthony Cheetham, Pieremanuele Canepa, Raphaele Clement

Abstract

In the pursuit of urgently-needed, energy dense solid-state batteries for electric vehicle and portable electronics applications, halide solid electrolytes offer a promising path forward with exceptional compatibility against high-voltage oxide electrodes, tunable ionic conductivities, and facile processing. For this family of compounds, synthesis protocols strongly affect cation site disorder and modulate Li⁺ mobility. In this work, we reveal the presence of a high concentration of stacking faults in the superionic conductor Li₃YCl₆ and demonstrate a method of controlling its Li+ conductivity by tuning the defect concentration with synthesis and heat treatments at select temperatures. Leveraging complementary insights from variable temperature synchrotron X-ray diffraction, neutron diffraction, solid-state nuclear magnetic resonance, density functional theory, and electrochemical impedance spectroscopy, we identify the nature of planar defects and the role of nonstoichiometry in lowering Li⁺ migration barriers and increasing Li site connectivity in mechanochemically-synthesized Li₃YCl₆ . We harness paramagnetic relaxation enhancement to enable ⁸⁹Y solid-state NMR, and directly contrast the Y-cation site disorder resulting from different preparation methods, demonstrating a potent tool for other researchers studying Y-containing compositions. With heat treatments at temperatures as low as 333 K (60°C), we decrease the concentration of planar defects, demonstrating a simple method for tuning the Li+ conductivity. Findings from this work are expected to be generalizable to other halide solid electrolyte candidates and provide an improved understanding of defect-enabled Li⁺ conduction in this class of Li-ion conductors.

Citation

Journal of the American Chemical Society

Volume

144

Issue

13

Pub Type

Journals

Keywords

Stacking Faults, Ion Conductor, diffraction, solid-state battery

Citation

Sebti, E. , Evans, H. , Chen, H. , Richardson, P. , White, K. , Giovine, R. , Koirala, K. , Xu, Y. , Gonzalez-Correa, E. , Wang, C. , Brown, C. , Cheetham, A. , Canepa, P. and Clement, R. (2022), Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor, Journal of the American Chemical Society (Accessed April 26, 2024)