Synthesis and characterization of novel fluorinated nitriles as non-flammable and high-voltage electrolytes for lithium/lithium-ion batteries

Abstract

Current carbonate or ether electrolytes for lithium-ion batteries suffer from high flammability, poor high-potential stability or complicated synthesis protocols. Herein, we design and successfully synthesize a series of novel fluorinated nitriles bridged by ether bond between the nitrile group and fluoroalkyl moiety. The relationship between the chemical structure of fluorinated nitriles (including the length of fluoroalkyl chain, partial fluorination of terminal group, and introduction of ethylene oxide units) and corresponding properties such as viscosity, dielectric constant, ionic conductivity, electrochemical stability window, flammability, solvation ability, are investigated systematically. Using the fluorinated nitriles as the main solvents, the formulated electrolytes not only exhibit non-flammable but also promise excellent stability for lithium batteries and 4.5 V high-voltage lithium-ion batteries.