Research progress of organic electrolyte for sodium ion battery

As the demand for large-scale batteries for electrical energy storage is increasing, sodium-ion batteries have attracted a lot of attention due to the abundance,cost-effectiveness of sodium resources and resemblance with lithium. In the key material selection of sodium ion battery, electrochemical performance and safety of a sodium-ion battery were affected by the electrolyte, which not only decides the electrochemical window and energy density, but also controls the electrode/electrolyte interfaces. In this paper, the basic requirements and classification of electrolyte of sodium ion battery were reviewed. The selective requirements of electrolyte in sodium ion batteries, the physicochemical properties of different sodium salts and the effects on solid electrolyte interface were discussed. Based on the compatibility of different solvents and materials as well as the energy storage mechanism of materials in different solvent systems, the solid electrolyte interface, rate and cycling performance obtained by materials in ether and ester based electrolytes were analyzed. Finally, the future development of sodium ion battery electrolyte in terms of matching with materials and key characterization methods were prospected.