Amorphization of Inorganic Solid Electrolyte Interphase Components and Its Impact on Enhancing Their Transport and Mechanical Properties

Structural Toughness of Fluorinated–Nitrided Interphase Passivation Layers for Lithium-Ion Batteries: A Reactive Molecular Dynamics Study

“…In a quest to explain changes in lithium kinetics at the SEI level, theoretical investigations found higher Li + diffusivity along grain boundaries, compared to pure crystalline LiF. , In more recent advancements, we observed a direct link between enhanced Li transport properties and a disturbed amorphous phase that would normally be unstable under ambient conditions . Furthermore, the presence of highly lithiophilic impurities, like nitrides, in LiF has been found to facilitate the otherwise elusive amorphous phase stability, dramatically improving transport and mechanical properties in the context of interfacial passivation. , This is consistent with recent experimental reports on the stabilizing influence of fluorinated–nitrided (FN) SEI layers, formed from the incorporation of both LiF-forming additives [such as lithium bis (fluorosulfonyl)­imide (LiFSI)] and Li 3 N-forming additives [like lithium nitrate (LiNO 3 )] in carbonate electrolytes. − The effective role of LiNO 3 seems to be linked to its spontaneous Li-induced decomposition, helping form uniform surface films comprising nitrides, oxynitrides, and oxides. , The lithiophilic nature of such nitride and oxide species obtained through NO 3 – breakdown was also shown to facilitate the amorphization of the inner SEI layer, producing enhanced interface properties like super Li + -ion conductivity . In fact, the rational amalgamation of fluoride-rich F-SEI and nitride-rich N-SEI into FN-SEI was seen to promote superior cycling stability when compared to individual F-SEI or N-SEI .…”

Synergetic impact of nitrate-based additives for enhanced solid electrolyte interphase performance

“…Introducing some new clarity in this area, we demonstrated, in our previous works, that transport and mechanical characteristics can be linked to disturbances in the structural phase. 53,54,90 Particularly, signicant amorphous phase-induced enhancement in Li-ion conductivity (s Li ) was observed for LiF, and presence of highly lithiophilic impurities like anionic nitrogen (N) or oxygen (O) was seen to facilitate the otherwise elusive amorphous phase stability. Keeping this in mind, it would make sense to incorporate a separate lithiophilic anions' source like lithium nitrate (LiNO 3 ), in tandem with a F-rich additive, to better optimize the solvation structure of Li + and enable the formation of a more robust inorganic SEI structure.…”