Preparation of Na₅YSi₄O₁₂-based Solid Sodium Battery Electrolyte and Its Conductive Behaviour

Although sodium-ion solid electrolytes have been studied for many years, their low conductivity at room temperature and an order of magnitude gap with organic liquid electrolytes are the main obstacles limiting their practical application. In this paper, high performance Na₅YSi₄O₁₂ solid electrolytes with hexagonal crystal structure were prepared by using solution-assisted solid-state reaction (SASSR) method, with NaNO₃, YN₃O₉·6H₂O and C₈H₂₀O₄Si as raw materials. The relationship between sintering temperature and dwelling time and ionic conductivity of Na₅YSi₄O₁₂ (NYS) were focused. The sample sintered at 1050 ℃ for 6 h had the highest ionic conductivity of 1.52 mS·cm^-1, with an activation energy of 0.215 eV.Compared with that of the one prepared with the commercial solid-phase reaction method, conductivity of the material in this work has been greatly improved. The increase in conductivity is attributed to the high sintering activity of the Na₅YSi₄O₁₂ powder and the unique 3D transport channel. The charge carriers can be transported along the channel or across different channels, thus leading to a higher conductivity.