Recent Advances in Non-Aqueous Liquid Electrolytes for High-Voltage Sodium-Ion Batteries

Sodium-ion batteries are considered one of the most promising candidates for lithium-ion batteries. Increasing charging voltage is an effective way to realize sodium-ion batteries with low cost and high energy density. However, the narrow voltage window of the existing electrolyte is a serious constraint. This review systematically summarizes the development of electrolytes for high-voltage sodium-ion batteries in recent years. Firstly, the basic characteristics and critical influencing factors of high-voltage electrolytes are presented. Secondly, the strategies of developing high-voltage sodium-ion electrolytes in recent years are systematically summarized, including the regulation of solvation structure, the characteristics and applications of new high voltage resistant solvents, and the action mechanism of high-voltage additives. Finally, the future development trend of sodium-ion high-voltage electrolytes is proposed, aiming to promote the breakthrough and application of high energy density sodium-ion batteries.