Cathode with Layers of Anode Reductant and Solid-Electrolyte Interphase

Described is a lithium-sulfur electrochemical cell in which the anode and the cathode are each equipped with a respective solid-electrolyte interphase (SEI) layer that inhibits lithium side reactions. On the cathode side, the SEI layer inhibits the shuttle effect by retaining soluble polysulfides within a cathode active layer while releasing and admitting lithium ions to and from the electrolyte. The cathode SEI is deposited, during cell formation, by depositing a layer of an anode reductant (e.g., metallic lithium) on the surface of the cathode. The resultant electrically conductive layer allows electrons to reduce adjacent electrolyte and form the cathode SEI from electrolyte decomposition products.