Boosting lithium compatibility and air stability of halide electrolytes through cyanamide substitution

Abstract

The application of halide electrolytes is hindered by poor lithium metal compatibility and low air stability. In this work, we partially substitute chloride ions in the halide electrolyte (Li₂ZrCl₆) with a triatomic linear cyanamide group (NCN²⁻). By utilizing the conjugated cyanamide group, lithium-ion migration is promoted, while significantly suppressing lithium dendrite growth. The assembled Li/Li symmetric cell maintains stable cycling for over 1100 hours. Impressively, ionic conductivity degradation is also significantly restrained when exposed to air with 10% humidity for 24 hours. When the modified halide electrolyte is paired with the lithium metal anode, the all-solid-state lithium batteries demonstrate outstanding electrochemical performance.