Surface Analysis of Solid Electrolyte Interphase on Binder-free Graphite Electrodes in Advanced Electrolytes

摘要

The solid electrode interphase (SEI) on graphite electrodes is important to the performance, calendar life, and safety characteristics of lithium-ion cells. This transaction examines the SEI formed on binder-free (BF) graphite electrodes prepared by electrophoretic deposition. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT1R) data were obtained on electrodes cycled in cells containing four electrolytes comprising ethylene carbonate (EC): ethylmethyl carbonate (EMC) (3:7 by wt.) solvent and 1.2M LiPF_6, 1M LiF_2BC_2O_4, 1M LiBF_4, or 0.7M LiB(C_2O_4)_2 salt. Our observations suggest that, in addition to solvent reduction, the reduction of electrolyte salts play an important role in SEI formation.