Organosilicon functionalized glycerol carbonates as electrolytes for lithium-ion batteries

Abstract

Two triethoxyl-/trimethoxyl-silyl functionalized glycerol carbonates and one disiloxanyl functionalized glycerol carbonate were synthesized through a cycloaddition reaction of carbon dioxide with allyl glycidyl ether followed by a hydrosilylation with the corresponding hydrosilanes. Their chemical structures were fully characterized by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy and their basic physicochemical properties including dielectric constant, viscosity, ionic conductivity, apparent lithium transference number and electrochemical window, were systematically measured. Trimethoxysilyl functionalized glycerol carbonate as electrolyte solvent with LiPF₆ (0.6 M) and lithium oxalyldifluoroborate (0.4 M) binary salts exhibited good cycling stability over 2.7–4.4 V in high-voltage-LiCoO₂/graphite full cells. Disiloxane functionalized glycerol carbonate acted as an efficient electrolyte additive to improve the wetting property on the separator in Li/LiCoO₂ cells.