Regulating the Interfacial Performance of All-Solid-State Sodium Batteries Using Lanthanum Substitution in a Na3Zr2Si2PO12 Solid Electrolyte

The main issues currently facing solid-state batteries are the low ionic conductivity of solid electrolytes and high interfacial resistance. By employing a doping strategy to introduce La3+ into the Na3Zr2Si2PO12 solid electrolyte increases the ionic conductivity to as high as 1.1 mS cm-1, promotes Na3La(PO4)2 interphase formation, and enhances interfacial charge transfer and cycling stability. The anode interfacial resistance of the Na3.1Zr1.9La0.1Si2PO12 electrolyte decreased to 75 Omega cm2 at room temperature, merely one-fourth smaller than that of Na3Zr2Si2PO12. Moreover, Na3.1Zr1.9La0.1Si2PO12 achieves superior stable sodium plating/stripping cycling over 1800 h, and its performance exceeds that of most reported sodium solid electrolytes. A solid-state Na3V2(PO4)3/Na3.1Zr1.9La0.1Si2PO12/sodium battery is assembled, demonstrating stable cycling performance with 84.5% capacity retention after 750 cycles. The enhancement of ionic conductivity in the solid electrolyte and the improvement of anode interfacial wettability have facilitated the advancement of solid-state sodium batteries.