As for spinel LiNi0.5Mn1.5O4, there is 4 V voltage plateau in the charge-discharge profiles. This voltage plateau can be reduced by an annealing process, however it is hard to avoid it completely. In this study, a new strategy of partial substitution for Mn by Mg is applied. There is no 4 V voltage plateau in the charge-discharge profiles of Mg-doped compound LiNi0.5Mn1.45Mg0.05O4. This compound exhibits good electrochemical properties which can be used as cathode material of lithium ion batteries. At 1 C rate, it can deliver a capacity of around 129 mAh g(-1) and remain good cycle performance. (C) 2013 Elsevier Ltd. All rights reserved.