Simplifying the Electrolyte Systems with the Functional Cosolvent.

The state-of-the-art electrolytes utilized in lithium-ion batteries are based on liquid carbonates combining a number of additives to fulfill the practical requirements including safety and low temperature. The plenty of components result in the quadruple times of probable radical groups involved into the interfacial reactions, rendering it too difficult to control the surface layer. This work tends to simplify the system with the fluorine-substituted ether as the functional cosolvent to expand the functions of basic electrolytes. The incorporation of this solvent enables the electrolyte to self-extinguish, reduces its freezing point to ∼75 °C lower, and assists in the formation of LiF-rich protective interlayers, resulting in the improvement of the rate capability, cryogenic performance, and cyclic stability for the LiNi1/3Co1/3Mn1/3O2 cathode. This novel design could significantly diminish the amount of necessary additives and possess the acceptable cost, which provides a probability to revitalize the development of liquid electrolytes.