Ether‐Based Electrolytes and the Solvation Structure in Sodium Ion Batteries

ABSTRACT Sodium‐ion batteries (SIBs) are promising candidates for large‐scale energy storage due to the cost‐effectiveness of sodium resources. Suitable and reliable electrolytes with excellent thermodynamic and kinetic properties as well as electrochemical and chemical stability are desired for SIBs. The higher donor number, nucleophilic chelating ability, and the novel co‐intercalation mechanism during the electrochemical process make ether an emerging electrolyte solvent in SIB. Understanding the functionality of ether solvents in batteries would promote the investigation of electrolyte. However, owing to the limitations of existing detection techniques, a comprehensive and in‐depth understanding of localized solvation structures and their evolution during electrochemical processes, which govern battery behavior, is still lacking. The recent investigations about the characterization of ether solvation structure, the solvent and salt impact on adjusting the formation of solid electrolyte interphase and practice application in both laboratory and industry are summarized and discussed in this review. In particular, the correlations between solvation structure, electrochemical behaviors and electrochemical performance are highlighted, aiming to provide insight into the rational design of high‐performance electrolytes for SIBs. Perspectives are proposed to advance research development, and we hope the review can shed light on the understanding of ether solvation structure and future applications in SIBs.