Two CoFe2O4 samples prepared at 600 and 1000 degrees C have been subjected to galvanostatic cycling in lithium test cells. Fe-57 Mossbauer spectra have been analyzed to elucidate the possible causes of capacity fading during the first cycles. Fe-57 conversion electron Mossbauer spectroscopy has been applied to distinguish between bulk and surface iron locations. This technique revealed the presence of reduced iron atoms near the surface of the sample annealed at 1000 degrees C. Their suitable accessibility to lithium may explain the better capacity retention observed for a large number of cycles. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3129691] All rights reserved.