Design principles for sodium superionic conductors

Shuo Wang; Jiamin Fu; Yunsheng Liu; Ramanuja Srinivasan Saravanan; Jing Luo; Sixu Deng; Tsun-Kong Sham; Xueliang Sun; Yifei Mo

doi:10.1038/s41467-023-43436-3

Design principles for sodium superionic conductors

Nat Commun. 2023 Nov 22;14(1):7615. doi: 10.1038/s41467-023-43436-3.

Authors

Shuo Wang^#¹, Jiamin Fu^#^{2

3}, Yunsheng Liu¹, Ramanuja Srinivasan Saravanan¹, Jing Luo², Sixu Deng², Tsun-Kong Sham³, Xueliang Sun⁴, Yifei Mo^{5

6}

Affiliations

¹ Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA.
² Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, N6A 5B9, Canada.
³ Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7, Canada.
⁴ Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, N6A 5B9, Canada. xsun9@uwo.ca.
⁵ Department of Materials Science and Engineering, University of Maryland, College Park, MD, 20742, USA. yfmo@umd.edu.
⁶ Maryland Energy Innovation Institute, University of Maryland, College Park, MD, 20742, USA. yfmo@umd.edu.

^# Contributed equally.

Abstract

Motivated by the high-performance solid-state lithium batteries enabled by lithium superionic conductors, sodium superionic conductor materials have great potential to empower sodium batteries with high energy, low cost, and sustainability. A critical challenge lies in designing and discovering sodium superionic conductors with high ionic conductivities to enable the development of solid-state sodium batteries. Here, by studying the structures and diffusion mechanisms of Li-ion versus Na-ion conducting solids, we reveal the structural feature of face-sharing high-coordination sites for fast sodium-ion conductors. By applying this feature as a design principle, we discover a number of Na-ion conductors in oxides, sulfides, and halides. Notably, we discover a chloride-based family of Na-ion conductors Na_xM_yCl₆ (M = La-Sm) with UCl₃-type structure and experimentally validate with the highest reported ionic conductivity. Our findings not only pave the way for the future development of sodium-ion conductors for sodium batteries, but also consolidate design principles of fast ion-conducting materials for a variety of energy applications.

Grants and funding

2118838/National Science Foundation (NSF)