Tailored Carbonate Based Non-Combustible Electrolyte for 5v Cathode of Lithium-Ion Batteries

Abstract

Electrolyte, as one of the most important part in electrochemical devices, is now still a critical bottleneck for the development of next-generation advanced batteries. For lithium (-ion) batteries, one of the limitations on achieving higher energy density and higher safety lies in the low oxidation stability (decomposing under 4.5V vs. Li/Li+) and high flammability of conventional carbonated based electrolytes. Herein, we report a LiPF6/DMC electrolyte with specific solution structure, which presents significant advances in battery performances. By altering the solution structure, the flammability of carbonate electrolytes is completely overcome, and meantime the electrochemical stability window is effectively expanded (> 6.0 V vs. Li/Li+). Meanwhile, the electrolyte demonstrates excellent compatibility with 5V LiNi0.5Mn1.5O4 cathode and remarkably extends the cycle life of LiNi0.5Mn1.5O4/Li battery and LiNi0.5Mn1.5O4/graphite battery. This work propels the development of safe and long life high energy density batteries and allows for re-evaluation of the battery (electro)chemistries, especially high voltage battery (electro)chemistries, regarding the mostly commonly used LiPF6/carbonate based electrolytes.

Keywords: Non-combustible electrolyte, High-concentration electrolyte, 5V cathode, Lithium-ion batteries