MgAl2O4-doped LiMn2O4 spinels, (LiMn2O4)(1-x)(MgAl2O4)(x) (x = 0, 0.02, 0.05, 0.10), were synthesized and the cycle performance as cathode material for lithium-ion secondary battery was investigated. Doping with MgAl2O4 improved the cycle performance of LiMn2O4 spinel. For (LiMn2O4)(0.95)(MgAl2O4)(0.05) the capacity fading was markedly suppressed compared to nondoped LiMn2O4. It is considered that stable Mg-O-Al bonds dispersed into the LiMn2O4 matrix stabilized the whole crystal lattice through the common oxygen arrangement between MgAl2O4 spinel and LiMn2O4 spinel and inhibited the deterioration of the crystal structure due to the repetition of lithium insertion and deinsertion, resulting in the improvement of cycle performance. (C) 2003 The Electrochemical Society.