Stable lithium/electrolyte interphase enabled by tailoring Li+ solvation structure and FEC additive in LiOTf/LiNO3 dual-salt sulfolane-based nonflammable electrolyte for lithium metal batteries
Year: 2026
Type: article
Abstract: Developing nonflammable electrolytes with stable lithium-metal interfaces and reversible Li plating/stripping remains a critical challenge for lithium metal batteries. Herein, a sulfolane-based nonflammable electrolyte containing lithium trifluoromethanesulfonate (LiOTf), lithium nitrate (LiNO3) and fluoroethylene carbonate (FEC) is developed by regulating Li+ solvation and interfacial chemistry. NMR spectroscopy and ab initio molecular dynamics simulations reveal that partial substitution of LiOTf with LiNO3 redistributes the first Li+ solvation shell, reducing sulfolane coordination while increasing anion participation. Raman and FT-IR analyses further indicate that FEC modifies the local interaction network among electrolyte components. The optimized Li[OTf/NO3]-FEC electrolyte exhibits a low viscosity of 34.4 cP, an ionic conductivity of 0.63 mS cm-1 and favorable self-extinguishing behavior. FEC also promotes an inorganic-rich SEI containing LiF, Li3N, LiNxOy, Li2O, Li2SO4 and Li2SO3, resulting in lower interfacial resistance and more uniform Li deposition. Consequently, Li//Li cells exhibit an overpotential of ~0.12 V and stable cycling for ~180 h at 0.5 mA cm-2 and 0.5 mAh cm-2, while Li//Cu cells maintain 97-98% Coulombic efficiency for over 100 cycles with an average efficiency of 96.48% by the modified Aurbach method. Li//LiMn2O4 cells retain 85.7% capacity after 587 cycles at 100 mA g-1 and 67.2% after 1600 cycles at 500 mA g-1. These results demonstrate that combining Li+ solvation regulation with FEC-assisted interphase engineering is an effective strategy for stable, nonflammable lithium metal batteries.
Source: Electrochemistry Communications
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,630
OpenAlex ID: W7223020157