Li⁺/Na⁺ Hybrid Ion Conduction Mechanism in the Superionic Conductor Li_3-xNa_xZr₂Si₂PO₁₂

Authors

• Yihong Wu, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.
• Xia Xie, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China; Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
• Lei Zhu, State Key Laboratory of Space Power-Sources Technology, Shanghai Institute of Space Power-Sources, Shanghai, 200245, China.
• Muran Yu, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
• Guotai Zhang, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
• Junchao Chen, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.Follow
• Shuying Sun, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China.Follow
• Youwei Wang, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China; Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.Follow
• Weiping Tang, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.Follow

Document Type

Communication

Corresponding Author(s)

Junchao Chen(junchaochen@sjtu.edu.cn);
Shuying Sun(shysun@ecust.edu.cn);
Youwei Wang(ywwang@mail.sic.ac.cn);
Weiping Tang(tangweiping@sjtu.edu.cn)

Abstract

Hybrid ion conductors that transport multiple ionic conductive species provide a useful platform for understanding how mixed-ion transport governs ionic conductivity within a single phase. However, the controlled introduction of multiple mobile ions into solid-state electrolytes and a mechanistic understanding of their migration within the framework remain challenging. Herein, a skeleton-retained Li⁺↔Na⁺ cationic exchange was used to simultaneously induce Li⁺ and Na⁺ cations into the NASICON-type framework of Li_3-xNa_xZr₂Si₂PO₁₂ (0 < x < 3). We show the interpenetration of NaO₆ and NaO₈ coordination polyhedra significantly influences the ionic conductivity of hybrid ion conductors. Computational analysis indicates that Na⁺ transfer from octahedral NaO₆ sites to octa-coordinated NaO₈ sites is thermodynamically favorable, accompanied by  Li⁺  relocation from NaO₈ to tetrahedral LiO₄ environments at former NaO₆ sites, thereby promoting Li⁺/Na⁺ site segregation. The increased occupation of Na⁺ at NaO₈ sites not only suppresses Na⁺ mobility due to bottleneck limitations but also hinders the formation of a continuous Li⁺ migration network, thereby reducing the room-temperature ionic conductivity from 1.78 to 0.50 mS·cm^-1. Upon re-exchange,  Na⁺  in the NaO₈ sites is replaced by Li⁺ in penta-coordinated LiO₅, which re-establish percolating ion-transport pathways for Li⁺ and enable reversible recovery of the overall conductivity. These results reveal a fast dual-ion conduction mechanism enabled by the interpenetrating occupation of Li⁺ and Na⁺ across the available sites. This work opens a new avenue for the development of hybrid ion conductors.

Graphical Abstract

Keywords

Hybrid ion conductors, Li+/Na+ cationic exchange, Dual-ion transport mechanism, Interpenetrating occupation

DOI

10.61558/2993-074X.3612

Online Date

4-22-2026

Recommended Citation

Yihong Wu, Xia Xie, Lei Zhu, Muran Yu, Guotai Zhang, Junchao Chen, Shuying Sun, Youwei Wang, Weiping Tang. Li+/Na+ Hybrid Ion Conduction Mechanism in the Superionic Conductor Li3-xNaxZr2Si2PO12[J]. Journal of Electrochemistry, doi: 10.61558/2993-074X.3612.