Polyelectrolyte Membranes Containing Lithium Malonato( difluoro) borate for Lithium Ion Systems

A new salt, lithium malonato(difluoro) borate (LiMDFB), and two similar analogues, were synthesized and incorporated into polymer electrolyte membranes to investigate the bulk and interfacial properties as both a binary salt system and a single-ion conducting electrolyte for lithium ion batteries. Symmetric lithium/lithium cells were assembled with membranes composed of polyethylene oxide (PEO) doped with LiMDFB analogues along with LiTFSI for comparison. Conductivities and exchange current densities were determined from electrochemical impedance spectroscopy measurements and the interfacial impedance was shown contribute significantly to the overall impedance for LiMDFB cells.