Lithium difluoro(oxalato)borate as salt for lithium-ion batteries

Lithium difluoro (oxalato) borate is reported as a salt for high-performance lithium-ion batteries with improved cycle life and power capability. The experimental results showed that lithium difluoro (oxalato) borate, LiC2O4BF2, can be reduced at about 1.7 V vs Li+/Li and forms a robust protective SEI film on the graphite surface, as lithium bis (oxalato) borate does. The lithium-ion cells using lithium difluoro (oxalato) borate-based electrolyte had very good capacity retention at 55 degrees C. The lithium-ion cells using the lithium difluoro (oxalato) borate-based electrolyte had very low interfacial impedance. Therefore, lithium difluoro (oxalato) borate is a promising salt for advanced lithium-ion batteries with improved capacity retention and power capability. (c) 2006 The Electrochemical Society.