In this work, gelatin is for the first time utilized to conduct polymer-assisted synthesis of LiNi0.5Mn1.5O4 as the cathode material for 5 V lithium rechargeable batteries. The effect of different amounts of gelatin on structural and morphological properties, electrochemical characterization of the obtained products are investigated by XRD, SEM, charge/discharge testing, cyclic voltammograms (CV) and electrochemical impedance spectroscopy (EIS), respectively. It's found that with the addition of moderate amount of gelatin, the sample displays a higher degree of crystallinity and phase purity, more uniform shape and monodispersed nanometric size. As a result, electrochemical cycling stability and rate performance are significantly enhanced. CV and EIS measurements further demonstrate that using an optimal amount of gelatin can improve electrochemical performance due to the reversible reaction, faster insertion/extraction of Li ions in the spinel structure and decreased interface independence. (C) 2013 Elsevier B.V. All rights reserved.