Dual‐Anionic Coordination Manipulation Induces Phosphorus and Boron‐Rich Gradient Interphase Towards Stable and Safe Sodium Metal Batteries

High-voltage sodium metal batteries (SMBs) present a viable pathway towards high-energy-density sodium-based batteries due to the competitive cost advantage and abundant supply of sodium resources. However, they still suffer from severe capacity decay induced by the notorious decomposition of the electrolyte under high voltage and unstable cathode/electrolyte interphase (CEI). In addition, the high reactivity of Na metal and flammable electrolytes push SMBs to their safety limits. Herein, a special dual-anion aggregated Na