Using a Boron-Based Anion Receptor Additive to Improve the Thermal Stability of LiPF_6-Based Electrolyte for Lithium Batteries

摘要

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 that addition of 0.1 M TPFPB maintained electrochemical stability of a LiPF_6-based electrolyte at 55 deg 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_2O_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 deg 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.