Jinglun Wang, Y. Mai, Hao Luo
Dec 1, 2016
Citations
1
Influential Citations
23
Citations
Journal
Journal of Power Sources
Abstract
Abstract Two fluorosilanes with oligo(ethylene oxide) unites were synthesized through hydrosilylation of chlorosilane with allyl substituted oligo(ethylene oxide) ether followed by fluorination with potassium fluoride. The synthesized fluorosilane compounds exhibited lower viscosity, higher dielectric constant and higher oxidation potential, compared with their non-fluorination counterparts. Difluoro(3-(2-(2-methoxyethoxy)ethoxy)propyl)methylsilane (DFSM 2 ), one of the two compounds, was evaluated as high-voltage and thermal stable electrolyte co-solvent with the conventional carbonate-based electrolytes. Using an optimized electrolyte of 1M LiPF 6 in EC/DFSM 2 /EMC (2/3/5 in vol .) with addition of 5 wt % fluoroethylene carbonate (FEC), high-voltage LiCoO 2 (LCO)/graphite full cell displayed outstanding cycling stability of 92.5% capacity retention after 135 cycles at 4.4 V upper cutoff voltage. Characterized by differential scanning calorimetry (DSC) analysis, the DFSM 2 -based electrolyte demonstrated higher thermal stability with lithiated graphite anode and delithiated LCO cathode, thus better safety feature compared with the conventional electrolyte.