Highly Soluble Lithium Nitrate-Containing Additive for Carbonate-Based Electrolyte in Lithium Metal Batteries

While lithium nitrate (LiNO 3 ) is widely utilized as an electrolyte additive in ether-based electrolytes for stable lithium deposition, use of LiNO 3 in conventional carbonate-based electrolytes is very limited due to the poor solubility of LiNO 3 in the carbonate-based electrolytes. Herein, a new LiNO 3 -containing electrolyte additive which is very soluble in carbonate-based electrolytes, 1-trimethylsilyl imidazole lithium nitrate adduct (TMSILN), has been synthesized by a simple method. The electrochemical performance is significantly improved in Li/Li and NCM622/Li cells with TMSILN additive containing electrolyte. Our extensive investigations reveal that the deposited lithium metal in the TMSILN additive-containing electrolyte has a circular morphology with a very thin (∼5 nm) surface film containing lithium nitrate decomposition products such as Li 3 N and LiN x O y . The improved electrochemical performance can be ascribed to the favorable features of the SEI and morphology of the deposited lithium in the presence of the TMSILN additive.