A mathematical model for the capacity fade of a LiMn2O4 (LMO) electrode is developed in this paper by including the acid attack on the active material and the solid electrolyte interphase (SEI) film formation on the LMO particle surface. The acid generated by the LiPF6 and the solvent decompositions are coupled to the manganese (Mn) dissolution. The decrease of the Li ion diffusion coefficient is involved as another contribution to the capacity fade, which is caused by the passive film formation on the active material surface. The effects of cell practical operation/ fabrication conditions and kinetics of side reactions on battery life are also investigated by utilizing the developed mathematical model. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.026302jes] All rights reserved.