Zwitterionic cellulosic membrane as a new separator with enhanced ionic conductivity and performance for lithium-ion batteries

Abstract

Separators are regarded as an essential component of lithium-ion batteries (LIBs) due to their critical roles in the electrochemical performance and safety of these batteries. The purpose of this study was to examine the structural and electrochemical properties of a new separator based on zwitterionic cellulose (Cell). The free radical polymerization method was used to graft 4-vinyl pyridinium propane sulfonate (4-VPPS) onto the hydroxyl groups of Cell, and the polymer solution in trifluoroacetic acid (TFA) solvent was prepared to form a thin membrane using an automatic film applicator. The results showed that the modified Cell (MCell) separator had significantly higher tensile strength and elastic modulus, as well as superior thermal and dimensional stability, when compared to control separators (polypropylene (PP) at transverse direction and unmodified Cell). The improved separator material effectively reduced the growth of lithium dendrites, which cause short circuits and battery failure. Furthermore, the zwitterionic Cell separator demonstrated improved cycling stability and rate capability. Overall, this study suggests that using MCell separators with 4-VPPS is a promising alternative for improving LIB performance. The findings help to advance battery technology by increasing safety, efficiency, and overall battery life. Graphical Abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2024.