Research on the high-voltage electrolyte for lithium ion batteries

The research for high-voltage cathode materials is one of important way to develop high energy density of lithium ion batteries. Electrolyte is an essential part of lithium ion batteries, which affects the electrochemical behavior through the interface reactions with the electrodes and its Li⁺ ion diffusion characters. The conventional carbonate/LiPF₆ electrolyte decomposes and tends to react with active cathode material when the voltage is higher than 4.5 V (vs Li/Li⁺), resulting in the poor performance. Therefore, searching for high-voltage electrolytes is essential to the realization of high-voltage lithium ion batteries. The progress on high-voltage electrolyte for lithium ion batteries is reviewed in this paper. The draw back and challenge of high-voltage electrolyte are also illustrated. On the theory of designing for electrolyte solvent molecular, the performance of high-voltage electrolyte is evaluated from aspects of new solvent system electrolytes and carbonate-based electrolytes. New electrolytes based on nitrile, sulfone and ionic liquids as high-voltage electrolytes with their advantage and drawbacks are analyzed. The action mechanisms of different additives in the carbonate-based electrolytes are discussed. In addition, the application of theoretical calculation methods on high-voltage electrolyte is discussed, and the vision utilizing theoretical calculation in designing novel high-voltage electrolyte is prospected.