Toward the Sustainable Lithium Metal Batteries with a New Electrolyte Solvation Chemistry
Seon Hwa Lee, Jang‐Yeon Hwang, Jun Ming, Zhen Cao, Hoang Anh Nguyen, Hun‐Gi Jung, Jaekook Kim, Yang‐Kook Sun
Abstract
Abstract Herein, a new solvation strategy enabled by Mg(NO 3 ) 2 is introduced, which can be dissolved directly as Mg 2+ and NO 3 − ions in the electrolyte to change the Li + ion solvation structure and greatly increase interfacial stability in Li‐metal batteries (LMBs). This is the first report of introducing Mg(NO 3 ) 2 additives in an ester‐based electrolyte composed of ternary salts and binary ester solvents to stabilize LMBs. In particular, it is found that NO 3 − efficiently forms a stable solid electrolyte interphase through an electrochemical reduction reaction, along with the other multiple anion components in the electrolyte. The interaction between Li + and NO 3 − and coordination between Mg 2+ and the solvent molecules greatly decreases the number of solvent molecules surrounding the Li + , which leads to facile Li + desolvation during plating. In addition, Mg 2+ ions are reduced to Mg via a spontaneous chemical reaction on the Li metal surface and subsequently form a lithiophilic Li–Mg alloy, suppressing lithium dendritic growth. The unique solvation chemistry of Mg(NO 3 ) 2 enables long cycling stability and high efficiency of the Li‐metal anode and ensures an unprecedented lifespan for a practical pouch‐type LMB with high‐voltage Ni‐rich NCMA73 cathode even under constrained conditions.