New Progress in Sodium-ion Battery Electrolyte Research

On May 7th, the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences announced new progress in the research of sodium-ion battery electrolytes. The sodium vanadium trifluorophosphate in phosphate-based sodium-ion batteries has a high theoretical specific energy (507Wh/kg, equivalent to lithium iron phosphate). However, sodium-ion batteries based on sodium vanadium trifluorophosphate have poor cycle stability, with issues such as vanadium dissolution and fluorine loss in the crystal cell, and electrolyte oxidation decomposition at high voltages. The team first analyzed and proved the root cause of capacity decay, then through coordinated regulation and optimization, the cycle stability of sodium vanadium trifluorophosphate-based sodium-ion batteries in the voltage range of 2 to 4.3V (vs. Na/Na+) significantly increased, with a capacity retention rate of over 95% after 1000 cycles at 1C, an increase of more than 60% compared to conventional electrolytes. The above work provides a theoretical basis and support for the development and practical application of high specific energy and high stability sodium-ion batteries.