Al Doped into Si/P Sites of Na3Zr2Si2PO12 with Conducted Na3PO4 Impurities for Enhanced Ionic Conductivity

Lixiao Zhang; Yimeng Liu; Jin Han; Chao Yang; Xing Zhou; Ye Yuan; Ya You

doi:10.1021/acsami.3c07680

Al Doped into Si/P Sites of Na₃Zr₂Si₂PO₁₂ with Conducted Na₃PO₄ Impurities for Enhanced Ionic Conductivity

ACS Appl Mater Interfaces. 2023 Sep 27;15(38):44867-44875. doi: 10.1021/acsami.3c07680. Epub 2023 Sep 12.

Authors

Lixiao Zhang¹, Yimeng Liu¹, Jin Han², Chao Yang¹, Xing Zhou¹, Ye Yuan¹, Ya You^{1

2

3}

Affiliations

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, P. R. China.
² International School of Materials Science and Engineering, School of Materials Science and Microelectronics, Wuhan University of Technology, Wuhan 430070, P. R. China.
³ Shaoxing Institute of Advanced Research, Wuhan University of Technology, Shaoxing, Zhejiang 312399, P. R. China.

PMID: 37700502
DOI: 10.1021/acsami.3c07680

Abstract

Natrium superionic conductor (NASICON) is a promising solid-state electrolyte because of its high stability under air as well as its safety. Doping is an effective way to improve its ionic conductivity, but there is limited information about the explanation of the doping sites. In this work, Al-doped NASICONs are designed. When Al doping is 0.3 (NAl_0.3ZSP), the ionic conductivity is the highest and is 5.08 × 10^-5 S cm^-1 at 30 °C, which is 3.3 times that of undoped NASICON. NAl_0.3ZSP consists of a NASICON structure (monoclinic and rhombohedral phases), an amorphous glassy phase, and Na₃PO₄ impurities. After Al doping, more Si/P sites are occupied by Al; thus, the ratio of Na₃PO₄ impurities increases. Na₃PO₄ at the grain boundary is beneficial for grain boundary resistance decrease, contributing to the decrease of the total resistance. Our work first provides a detailed explanation of doped-Al sites and interprets their effects on ionic conductivity.

Keywords: Al-doped NASICONs; Na3Zr2Si2PO12; conducted Na3PO4 impurities; grain boundary resistance; ionic conductivity.