NASICON-structured Na3.1Zr1.95Mg0.05Si2PO12 solid electrolyte for solid-state sodium batteries

Using stable inorganic solid electrolyte to replace organic liquid electrolyte could significantly reduce potential safety risks of rechargeable batteries. Na-superionic conductor (NASICON)-structured solid electrolyte is one of the most promising sodium solid electrolytes and can be employed in solid-state sodium batteries. In this work, a NASICON-structured solid electrolyte Na 3.1 Zr 1.95 Mg 0.05 Si 2 PO 12 was synthesized through a facile solid-state reaction, yielding high sodium-ionic conductivity of 1.33 × 10 −3  S·cm −1 at room temperature. The results indicate that Mg 2+ is a suitable and economical substitution ion to replace Zr 4+ , and this synthesis route can be scaled up for powder preparation with low cost. In addition to electrolyte material preparation, solid-state batteries with Na 3.1 Zr 1.95 Mg 0.05 Si 2 PO 12 as electrolyte were assembled. A specific capacity of 57.9 mAh·g −1 is maintained after 100 cycles under a current density of 0.5C rate at room temperature. The favorable cycling performance of the solid-state battery suggests that Na 3.1 Zr 1.95 Mg 0.05 Si 2 PO 12 is an ideal electrolyte candidate for solid-state sodium batteries.