Behavior of NO₃⁻-Based Electrolyte Additive in Lithium Metal Batteries

While lithium metal is highly desired as a next-generation battery material due to its theoretically highest capacity and lowest electrode potential, its practical application has been impeded by stability issues such as dendrite formation and short cycle life. Ongoing research aims to enhance the stability of lithium metal batteries for commercialization. Among the studies, research on N-based electrolyte additives, which can stabilize the solid electrolyte interface (SEI) layer and provide stability to the lithium metal surface, holds great promise. The NO₃⁻ anion in the N-based electrolyte additive causes the SEI layer on the lithium metal surface to contain compounds such as Li₃N and Li₂O, which not only facilitates the conduction of Li⁺ ions in the SEI layer but also increases its mechanical strength. However, due to challenges with the solubility of N-based electrolyte additives in carbonate-based electrolytes, extensive research has been conducted on electrolytes based on ethers. Nonetheless, the low oxidative stability of ether-based electrolytes hinders their practical application. Hence, a strategy is needed to incorporate N-based electrolyte additives into carbonate-based electrolytes. In this review, we address the challenges of lithium metal batteries and propose practical approaches for the application and development of N-based electrolyte additives.