EV lithium metal battery test cell hits 9,000-hour stability milestone

Researchers from Nankai University and collaborators in China have developed a novel fluorinated deep eutectic gel electrolyte (DEGE) that significantly advances lithium metal battery (LMB) technology by addressing critical safety and performance challenges. This new electrolyte enables symmetric lithium-lithium cells to cycle stably for over 9,000 hours and lithium-lithium iron phosphate (Li||LiFePO4) cells to retain 81.7% capacity after 2,500 cycles. It also maintains stability at elevated temperatures (80°C) for 300 cycles. The innovation centers on the use of fluorinated amides, particularly 2,2,2-trifluoro-N-methylacetamide, which facilitates rapid formation of a compact, mechanically strong solid electrolyte interphase (SEI) enriched with lithium fluoride (LiF) and lithium nitride (Li3N). This robust interface effectively suppresses dendrite formation, a major safety hazard in LMBs. The gel electrolyte format