Analysis of the Decomposition Products of Lithium Hexafluorophosphate in the Electrolytic Solution of Lithium-Ion Rechargeable Batteries by Column-Switching Ion Chromatography (Parts 1+2)
A composition of conducting salt lithium hexafluorophosphate (LiPF6) dissolved in a mixture of organic carbonates remains the dominant electrolyte formulation for commercial lithium ion batteries manufactured nowadays. Its well-balanced properties providing high conductivity, and application in high temperature range guaranteed the commercial success. High chemical and thermal instability of LiPF6 is the reason for the formation of decomposition products including hydrofluoric acid and inorganic as well as organic phosphates.
Ion chromatography is an analytical method for analysis of anionic decomposition products helping to evaluate the decomposition degree of the electrolytes. Nevertheless, the analysis time can be unacceptable long due to extremely high retention of PF6- on most ion-exchange columns. Shimadzu´s column-switching ion chromatography provides a solution for fast, sensitive and reliable analysis of fluoride and other inorganic phosphates in lithium ion battery electrolytes. The method can be applied for quality control of fresh-prepared electrolytes as well as for aged electrolytes for analysis of other decomposition products such as inorganic phosphates.