Enhancing ionic conductivity in solid electrolyte by relocating diffusion ions to under-coordination sites
Lei Zhu, Youwei Wang, Junchao Chen, Wenlei Li, Tiantian Wang, Jie Wu, Songyi Han, Yuanhua Xia, Yongmin Wu, Mengqiang Wu, Fangwei Wang, Yi Ying Zheng, Luming Peng, Jianjun Liu, Liquan Chen, Weiping Tang
Abstract
Solid electrolytes are highly important materials for improving safety, energy density, and reversibility of electrochemical energy storage batteries. However, it is a challenge to modulate the coordination structure of conducting ions, which limits the improvement of ionic conductivity and hampers further development of practical solid electrolytes. Here, we present a skeleton-retained cationic exchange approach to produce a high-performance solid electrolyte of Li 3 Zr 2 Si 2 PO 12 stemming from the NASICON-type superionic conductor of Na 3 Zr 2 Si 2 PO 12 . The introduced lithium ions stabilized in under-coordination structures are facilitated to pass through relatively large conduction bottlenecks inherited from the Na 3 Zr 2 Si 2 PO 12 precursor. The synthesized Li 3 Zr 2 Si 2 PO 12 achieves a low activation energy of 0.21 eV and a high ionic conductivity of 3.59 mS cm −1 at room temperature. Li 3 Zr 2 Si 2 PO 12 not only inherits the satisfactory air survivability from Na 3 Zr 2 Si 2 PO 12 but also exhibits excellent cyclic stability and rate capability when applied to solid-state batteries. The present study opens an innovative avenue to regulate cationic occupancy and make new materials.