Abstract: The spinel LiMn2O4 was synthesized at 700, 750, 800 and 850°C separately by solid reaction, of which different samples were investigated via X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance testing. The results showed that the lattice constants of all samples are greater than that of the standard spinel LiMn2O4, with finer grain size distributed in the range 0.2-0.4 μm. The cyclic voltammetric testing result indicated that the Li⁺ deinsertioninsertion process is performed in two steps and the electrode surface is passivated, then gradually stabilized in the cyclic process, especially the cyclic voltammetric curve of the sample synthesized at 750°C shows good symmetry. The AC impedance testing showed that the electrode process is controlled by two state parameters instead of one.