Solid Electrolyte Based on Succinonitrile and LiBOB

This paper reports physical and electrochemical properties of a solid electrolyte for lithium batteries formed by doping a plastic crystal solvent, succinonitrile, with lithium bioxalato borate (LiBOB). Thermal properties, solubility limits, conductivity, compatibility with lithium, and range of electrochemical stability have been studied. Succinonitrile doped with 4 mol % LiBOB is a solid at room temperature and melts near 50\ub0C. Electrochemical cells employing either LiFePO\u2084 or Li\u2081.\u2082Mn\u2080.\u2084Ni\u2080.\u2083Co\u2080.\u2081O\u2082 as the active cathode material and lithium metal as the anode were evaluated. This solid electrolyte showed excellent performance when combined with a LiFePO\u2084 cathode, delivering a reversible discharge capacity of ~142 mAh g\u207b\ub9 with very good capacity retention. However, with the Li\u2081.\u2082Mn\u2080.\u2084Ni\u2080.\u2083Co\u2080.\u2081O\u2082 cathode, the cell\u2019s capacity retention was not as good exhibiting a discharge capacity that decreased from 194 mAh g\u207b\ub9 in the first cycle to 149 mAh g\u207b\ub9 at 20th cycle.Peer reviewed: YesNRC publication: Ye