LiNi0.5Mn1.5O4 (LNMO) composite electrodes having the same formulation as to percentage of active material mass, binder and carbons, including reduced graphene oxide, were characterized in EC: DMC – 1M LiPF6 by cyclic voltammetry, charge/discharge cycles and impedance spectroscopy. The results demonstrate the beneficial effect on the electrode cycling stability in increasing C-rate to 1C, in limiting the charge voltage at 4.8 V and in covering the LNMO by partially reduced graphene oxide. The paper also discusses the evaluation of lithium diffusion coefficient in LNMO from cyclic voltammetry data in regard to the discrepancies reported in literature on this matter.