Stability of Inactive Components of Cathode Laminates for Lithium Ion Batteries at High Potential

The stability of inactive components in LIB (lithium ion batteries) electrodes upon exposure to high potentials can affect cell performance. A series of Li/ inactive component cells with aluminum, conductive carbon, and graphite as the inactive component were prepared and stored at high potential for one week. Electrochemical measurements and ex-situ surface analysis, including TEM (transmission electron microscopy), XPS (X-ray photoelectron spectroscopy), and FTIR (Fourier transform infrared spectroscopy), were conducted to investigate the stability of inactive components in the presence of LiPF6 in 3:7 ethylene carbonate (EC) and ethyl methyl carbonate (EMC) electrolyte at different potentials. The results show that all components are stable upon storage at 4.3 V. Storage at 4.6 or 4.9 V results in no aluminum corrosion, but limited decomposition on conductive carbon and greater decomposition on graphite. Storage at 5.3 V results in significant electrolyte oxidation to generate poly(ethylene carbonate) on the surface of all inactive electrodes and aluminum corrosion. (C) 2014 The Electrochemical Society. All rights reserved.