Adapting Crystal Structure and Grain Boundaries through Sm3+ Doping in Na3Zr2Si2PO4 for Boosting Applicability in Sodium Solid-State Batteries

Peifeng Wang; Yao Niu; Kai Zhang; Wenqiang Hou; Xianghua Yao; Youlong Xu

doi:10.1021/acsami.3c14086

Adapting Crystal Structure and Grain Boundaries through Sm³⁺ Doping in Na₃Zr₂Si₂PO₄ for Boosting Applicability in Sodium Solid-State Batteries

ACS Appl Mater Interfaces. 2024 Jan 17;16(2):2877-2887. doi: 10.1021/acsami.3c14086. Epub 2024 Jan 4.

Authors

Peifeng Wang^{1

2}, Yao Niu^{1

2}, Kai Zhang^{1

2}, Wenqiang Hou^{1

2}, Xianghua Yao^{1

2}, Youlong Xu^{1

2}

Affiliations

¹ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
² Shaanxi Engineering Research Center of Advanced Energy Materials & Devices, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China.

PMID: 38174722
DOI: 10.1021/acsami.3c14086

Abstract

Solid-state sodium batteries represent a highly promising option for future electrochemical energy storage applications. The ionic conductivity of solid-state electrolytes is one of the significant factors limiting the development of solid-state batteries. In this study, we establish that Sm³⁺ doping effectively boosts the ionic conductivity of Na₃Zr₂Si₂PO₁₂ (NZSP). The optimal composition, Na_3.2Zr_1.8Sm_0.2Si₂-PO₁₂ (NZSP-S20), exhibits a total conductivity of 1.87 mS cm^-1 at 23 °C. Structural and microscopic morphology analyses reveal that Sm³⁺ doping enhances the ionic conductivity of NZSP through structural modulation, phase fraction adjustment, and grain size reduction. High-frequency impedance spectroscopy (40 Hz to 110 MHz) demonstrates that bulk and grain boundaries contribute 49.4 and 50.6%, respectively, to the total conductivity. The structural and microscopic morphology analyses reveal that Sm³⁺ doping enhances the ionic conductivity of NZSP. Furthermore, the critical current density (CCD) attained in the symmetric cell, assembled by using NZSP-S20 as the solid-state electrolyte and NaSn alloy as the electrode, reaches 2.2 mA cm^-1. These results furnish a theoretical foundation for comprehending the modification of solid-state electrolytes.

Keywords: NZSP; NaSn alloy; Sm3+ doping; ionic conductivity; solid-state electrolyte.