A LiNi0.5Mn1.5O4 material with nanoplate morphology and ordered spinel phase is synthesized via co-precipitation method. From the results of XRD, FT-IR, SEM and TEM analysis, it can be seen that the LiNi0.5Mn1.5O4 sample possess a crystal structures of the space groups of P4(3)32 and plate-like morphology exposed {100} and {110} surfaces. The electrochemical tests show that it exhibits an acceptable rate capability, however, the cycling property, especially the stored performance is unsatisfactory. The following electrochemical impedance spectroscopy, SEM and ICP characterizations reveal the relationship between the surfaces and their electrochemical properties: during cycling or storing process, a charge transfer between Ni and Mn is taken place on the {100} and {110} surfaces, resulting in declines in the valence of Mn(IV). Then, the Mn could dissolve from spinel electrode surfaces into electrolyte undergoing a disproportionation reaction of Mn3+. Last, these results lead to the capacity retention and voltage platform continues to deteriorate.