Abstract
All-solid-state sodium (Na) batteries (ASSSBs) have attracted considerable attention due to their inherent safety and low cost. Developing sodium sulfide electrolytes with high Na(+) ionic conductivity and excellent stability in contact with sodium metal anodes is crucial to realize high-performance ASSSBs. Herein, a tungsten (W) and chlorine (Cl) co-doped Na(2.85)Sb(0.95)W(0.05)S(3.9)Cl(0.1) solid electrolyte is effectively prepared through melt-quenching combined with a subsequent annealing process. Through W-Cl co-doping, Na vacancies are introduced into the Na(3)SbS(4) electrolyte, thereby enhancing the ionic conductivity from 0.92 mS cm(-1) to 12.66 mS cm(-1). Meanwhile, the in situ formed NaCl-based electronically insulating interphase layer between Na(2.85)Sb(0.95)W(0.05)S(3.9)Cl(0.1) and the sodium metal effectively suppresses interfacial side reactions and improves interfacial stability. The obtained Na/Na(2.85)Sb(0.95)W(0.05)S(3.9)Cl(0.1)/Na symmetric cell demonstrates stable cycling over 800 h at 0.05 mA cm(-2). Moreover, the TiS(2)/Na(2.85)Sb(0.95)W(0.05)S(3.9)Cl(0.1)/Na ASSSB realizes an initial charge capacity of 142.2 mAh g(-1) at 0.1C, maintaining a capacity retention of 81.6% after 100 cycles. This work presents a viable approach for designing sodium sulfide electrolytes that combine high ionic conductivity with superior stability with a sodium anode.