XU Yao, LIU Limin, ZHOU Xiaoliang, GUO Weilin, LI Jie, GUO Xinru
(College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan, China)

Abstract: In recent years, sodium-ion solid-state batteries have gradually attracted attentions as a member of rechargeable batteries. In solid-state batteries, liquid electrolytes are avoided, thus diminishing the risks such as leakage and explosion. At present, it is still a challenge to increase the ionic conductivity of solid-state electrolytes. In this study, Zr ⁴⁺ was introduced into Na₅YSi₄O₁₂ (NYS), where NaNO₃, YN₃O₉·6H₂O, C8H₂₀O₄Si and ZrO(NO₃)₂·xH₂O were used as starting materials. A solution-assisted solid-phase reaction method (SASSR) was employed to prepare the solid electrolytes Na_5−xY_1−xZr_xSi₄O₁₂ (x=0.04, 0.06, 0.08, 0.10, 0.12) with hexagonal crystal structure. The effect of Zr4+ on ionic conductivity of Na_5−xY_1−xZr_xSi₄O₁₂ (NYZS) was studied, while the maximum ionic conductivity of 2.13 mS·cm⁻¹ was achieved at x=0.08, with an activation energy of 0.222 eV. Compared with that of NYS, the conductivity of NYZS is greatly increased, due to the presence of sodium vacancies after Zr⁴⁺doping. In summary, Na_5−xY_1−xZr_xSi₄O₁₂ is a competitive sodium-ion solid-state electrolyte, which is expected to become promising candidate for new generation of energy conversion.
Key words: sodium-ion battery; solid-state electrolyte; Na_5−xY_1−xZr_xSi₄O₁₂; ionic conductivity; ionic doping