New battery electrolyte formula ditches fluorine, cuts costs without sacrificing safety
Researchers have developed a fluorine-free electrolyte for lithium metal batteries that maintains performance while reducing manufacturing complexity and expense. The breakthrough matters to EV makers and battery suppliers racing to lower production costs while meeting safety and flame-resistance standards—potentially opening cheaper pathways to next-generation battery technology.
Originaltitel: Fluorine-free triazine-based dual-salt electrolyte enabling stable lithium metal batteries
<p>Here, we introduce a fluorine-free and flame-retardant dual-salt electrolyte formulation based on a new electron-deficient aromatic and Hückel-type lithium 4,6-diethoxy-2-oxo-2H-1,3,5-triazin-5-ide (LiDET) salt in combination with lithium bis(oxalato)borate (LiBOB) salt, both dissolved in a triethyl phosphate (TEP) solvent with vinylene carbonate (VC) as an additive. The interactions between BOB and DET anions promote a loosely coordinated Li+ solvation sheath, which results in enhanced interfacial stability of electrodes. The Li||Li symmetric cells maintain stable overpotentials during prolonged cycling, while the full cells demonstrate a capacity retention of 91% in Li||NMC811 cell after 500 cycles and 94% in Li||LTO cell after 200 cycles. The dual-salt electrolyte facilitates the formation of stable cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) layers as confirmed with X-ray photoelectron spectroscopy (XPS), where the presence of species such as Li3N, LiNxOy, B–N, and Li–B–O is evident. Overall, this study paves the way for development of fluorine-free and flame-retardant electrolytes for lithium metal batteries (LMBs), especially for high-voltage cathodes like NMC811.</p>