Stable sodium metal anode enhanced by advanced electrolytes with SbF_(3) additive

The practical application of sodium metal batteries(SMBs)is hampered due to the inferior interfacial stability between Na metal and conventional electrolytes.Therefore,a high-concentration electrolyte is proposed to solve this issue.However,high viscosity,low ionic conductivity,and unsatisfactory wettability toward the separator need to be overcome.In this study,a localized highconcentration electrolyte(LHCE)is formulated with1 wt%SbF_(3)as an interface-stabilized additive to protect the Na metal anode.This reformulated LHCE retains the special coordination structure in HCE with improved wettability and high ionic conductivity.Moreover,the introduction of the SbF_(3)additive into the LHCE resulted in a bilayer-structured solid electrolyte interface(SEI)including a Na-Sb alloy inner layer and a NaF-rich outer layer on the Na metal.As expected,the NaIINa cells using LHCE+1 wt%SbF_(3)show a long cycle lifespan of over1200 h at 0.5 mA·cm^(-2)with negligible polarization,and NaIINa_(3)V_(2)(PO_(4))_(3)cells exhibit a high capacity exceeding 97 mAh·g^(-1)at 40 C.