Nb-doped LiMn 2 O 4 materials were synthesized by a solid state process, and the structure and kinetic performance were characterized by TG-DTA, XRD, SEM, CV, and EIS. TG-DTA shows that the decomposition reaction has almost completed and all reactions have finished at the temperature of 590°C. XRD indicates that the all samples are in accordance with the standard spinel LiMn 2 O 4 . However, it can be found that little Nb 5+ ions do not completely substitute Mn 3+ ions of LiMn 2−1.667x Nb x O 4 (x=0.02, 0.03, 0.04). SEM reveals that the average particle size of all samples is about 1μm. CV exhibits that the improved reversibility and dynamic behaviors of LiMn 2 O 4 can be attributed to the Nb doping. EIS demonstrates that Nb doping decreases the charge transfer resistance of LiMn 2 O 4 , and then reduces the cell impedance. Nb doping results in lower electrode polarization and a high lithium ion diffusion coefficient, and can effectively improve the kinetic performance of LiMn 2 O 4 .