Constructing a Na3Sb-Incorporated Solid Electrolyte Interphase by Rational Composite Electrode Design for Stable Sodium Metal Batteries.

The sluggish ionic conductivity and undesirable electronic migration within the native solid electrolyte interphase (SEI) of Na anodes are among the primary factors hindering the development of sodium-metal batteries. Herein, this study proposes a strategy for stabilizing the SEI through the fabrication of Na/Na3Sb (NNS) composite foil, which is achieved via spontaneous reaction between Sb powder and Na foil during mechanical rolling. The uniformly dispersed Na3Sb participates in the formation of SEI, improving the Na plating/stripping behaviors and suppressing the Na dendrite growth because of its high ionic conductivity, strong electronic blocking capability, and high Na affinity. As a result, the symmetrical NNS||NNS cell exhibits a stable cycling exceeding 1000 h at mA cm-2 and 1 mAh cm-2, while the Na||Na symmetric cell undergoes short-circuit failure after 34 h. The full cell incorporating the Na3V2(PO4)3 cathode demonstrates a low capacity fade of only 6.4% after 600 cycles at 5 C.