Synergy Effect of Trimethyl Borate on Protecting High-Voltage Cathode Materials in Dual-Additive Electrolytes.

The lack of electrolyte that is stable under high potentials hinders the application of high-voltage cathode materials for lithium batteries; the introduction of electrolyte additives is clearly the most effective solution to address this issue. Herein, we investigated the synergistic effects of trimethyl borate (TMB) in two dual-additive electrolytes on protecting the LiNi0.8Co0.1Mn0.1O2 and LiCoO2 cathode materials under high potentials. The interactions of TMB with fluoroethylene carbonate and the catalysis of the decomposition product of TMB to tetramethylene sulfone lower the onset oxidation potential of these additives and are beneficial in forming a stable cathode electrolyte interphase film on the cathode materials. This work sheds light on another way of electrolyte designing for high-voltage cathode materials.