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

The possibility of using a strong anion coordinate agent, tris(pentafluorophenyl) borane (TPFPB), to suppress the thermal decomposition of -based electrolyte was studied. Cyclic voltammogram measurements showed that addition of 0.1 M TPFPB maintained electrochemical stability of a -based electrolyte at 55°C for a week, while under the same conditions severe degradation in electrochemical stability was observed in the same -based electrolyte without the TPFPB additive. A cell with a composite -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 -based electrolyte. © 2002 The Electrochemical Society. All rights reserved.