Using a Boron-Based Anion Receptor Additive to Improve the Thermal Stability of LiPF[sub 6]-Based Electrolyte for Lithium Batteries

Abstract

The possibility of using a strong anion coordinate agent, tris(pentafluorophenyl) borane (TPFPB), to suppress the thermal decomposition of LiPF 6 -based electrolyte was studied. Cyclic voltammogram measurements showed thataddition of 0.1 M TPFPB maintained electrochemical stability of a LiPF 6 -based electrolyte at 55°C for a week, while under the same conditions severe degradation in electrochemical stability was observed in the same LiPF 6 -based electrolyte without the TPFPB additive. A Li/LiMn 2 O 4 cell with a composite LiPF 6 -based electrolyte containing 0.1 M TPFPB additive also exhibited superior capacity retention and cycling efficiency at 55°C than a cell with an electrolyte without additive. These data demonstrate the excellent effect of TPFPB additive in improving the thermal stability of LiPF 6 -based electrolyte.