A series of RuO2 modified LiNi0.5Mn1.5O4 materials are successfully prepared by the precipitation method. X-ray photoelectron spectroscopy confirms the presence of Ru4+ in the materials. Scanning electron microscope and high resolution transmission electron microscope show that RuO2 covers the surface of LiNi0.5Mn1.5O4 particles. The amounts of RuO2 in the materials are determined to be 1.6wt.%, 2.0wt.% and 3.0wt.%, respectively. The electrochemical kinetics of the materials is studied by cyclic voltammetry and electrochemical impedance spectroscopy. The results show that RuO2 modification decreases the polarization of the electrode, prevents the side reactions of the electrode and the electrolyte, and improves the charge transfer reactions at the electrode interface, all of which are beneficial for the electrochemical properties of LiNi0.5Mn1.5O4. In all samples tested, the one containing 2.0wt.% of RuO2 exhibits superior electrochemical performance. It shows discharge capacities of 131.7mAhg−1 (room temperature) and 129.7mAhg−1 (60°C) at the 0.5C rate with the corresponding capacity retention of 97.7% and 97.2% after 100 cycles. In addition, the material delivers high discharge capacities of 104.5mAhg−1at the 5C rate and 66.1mAhg−1 at the 10C rate, demonstrating its excellent rate capability.