Atomically bonding Na anodes with metallized ceramic electrolytes by ultrasound welding for high‐energy/power solid‐state sodium metal batteries

Abstract A solid‐state sodium metal battery has cut a striking figure in next‐generation large‐scale energy storage technology on account of high safety, high energy density, and low cost. Nevertheless, the large interfacial resistance and sodium dendrite growth originating from the poor interface contact seriously hinder its practical application. Herein, a modified ultrasound welding was proposed to atomically bond Na anodes and Au‐metalized Na3Zr2Si2PO12 electrolytes associated with the in situ formation of Na–Au alloy interlayers. Thereupon, intimate Na3Zr2Si2PO12–Au/Na interfaces with a low interfacial resistance (~23 Ω cm2) and a strong dendrite inhibition ability were constructed. The optimized Na symmetric battery can cycle steadily for more than 900 h at 0.3 mA cm−2 under a low overpotential (