Conduction/Densification Enhancement of Na1+X Zr2Si x P3-X O12 Nasicon Solid Electrolyte for Solid-State Na Batteries

Abstract

Due to the better safety feature, replacing organic liquid electrolyte with ceramic solid electrolytes (SE) may effectively suppress the fire incidents caused by conventional rechargeable batteries. Recently, solid-state batteries using Na+ ion conductors tend to receive much attention because the abundance of Na in earth’s crust. However, solid-state batteries (SSBs) have been suffered by the relatively high interface polarization between electrode and SE. For higher Na+ conductivity, Na1+x Zr2Si x P3-x O12 with NASICON (Na Super Ionic Conductor) structure is selected for this study. Although solid state reaction is adopted, it is believed the selection of precursors may be critical for better crystallization and densification of Na1+x Zr2Si x P3-x O12. For instance, adequate amount of Na2CO3 may be used as the Na source as well as flux for densification. Thus, the objectives of this study is to (1) to identify the role of precursors such as Na2CO3 for conduction/densification of NASICON, (2) to search the appropriate temperature for synthesis/crystallization of NASICON, (3) to investigate the factors, such as crystallinity/density, affecting the ionic conductivity. During the different stages of processing, the structural, microstructural and electrical properties of decomposed precursors and resultant NASICON will be examined using XRD, SEM and DC/AC impedance measurements.