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

Authors

• Yi-Hong 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
• Mu-Ran Yu, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
• Guo-Tai Zhang, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
• Jun-Chao Chen, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, ChinaFollow
• Shu-Ying Sun, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, ChinaFollow
• You-Wei 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, ChinaFollow
• Wei-Ping Tang, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, ChinaFollow

Corresponding Author

Jun-Chao Chen (junchaochen@sjtu.edu.cn);
Shu-Ying Sun (shysun@ecust.edu.cn);
You-Wei Wang (ywwang@mail.sic.ac.cn);
Wei-Ping 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 that 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 conductor, Li+/Na+ cationic exchange, Dual-ion transport mechanism, Interpenetrating occupation

DOI Link

https://doi.org/10.61558/2993-074X.3612

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Date

2026-06-28

Online Available Date

2026-04-22

Revised Date

2026-04-01

Received Date

2026-02-07

Recommended Citation

Yi-Hong Wu, Xia Xie, Lei Zhu, Mu-Ran Yu, Guo-Tai Zhang, Jun-Chao Chen, Shu-Ying Sun, You-Wei Wang, Wei-Ping Tang. Li⁺/Na⁺ Hybrid Ion Conduction Mechanism in the Superionic Conductor Li_3–xNa_xZr₂Si₂PO₁₂[J]. Journal of Electrochemistry, 2026, 32(6): 2613001.
DOI: 10.61558/2993-074X.3612
Available at: https://jelectrochem.xmu.edu.cn/journal/vol32/iss6/1