<p>Incorporating LiNO₃ into carbonate electrolytes to form a N-containing solid electrolyte interphase represents an effective strategy to improve the stability of lithium electrodes for high-energy rechargeable lithium metal batteries. However, this approach is limited by the low solubility of LiNO₃ in such electrolytes. In this context, N-methyl-2-pyrrolidone (NMP) has previously been shown to be a promising carrier for significantly enhancing LiNO₃ solubility. Nevertheless, the underlying influence of LiNO₃/NMP on carbonate electrolytes remains poorly understood. In this work, we systematically study LiNO₃/NMP/carbonate electrolytes for lithium electrodes, with a focus on the influences of different electrolyte salts, concentrations, and carbonate solvents, along with the associated kinetics and interfaces. The presence of LiNO₃/NMP alters surface reactions, leading to the formation of N–Li/N–C/N–H_x, C–Li/O–C=O, and LiF species in the solid electrolyte interface (SEI) layer, which improve the stability of lithium electrodes. With the modified SEI, a CE of 98.8% is achieved.</p>