Surface Chemistry of Carbon-Treated LiFePO[sub 4] Particles for Li-Ion Battery Cathodes Studied by PES

Abstract

Photoelectron spectroscopy (PES) was used for depth-profile characterization of the interface formed on carbon-treated particles in the cathode of a lithium-ion battery after electrochemical cycling at 23 and 40°C in a 1 M mixture of ethylene carbonate and diethyl carbonate. Products from solvent reactions (such as polycarbonates) were not detected at the carbon-treated surface, contrary to findings for other cathode materials. Salt-based products like LiF, - and -type compounds were found on the cathode surface after cycling. Larger amounts of these compounds were detected on the surfaces of electrodes cycled at 40°C. © 2003 The Electrochemical Society. All rights reserved.