Abstract: The cathode materials, Na_0.46Ni_0.26Mn_0.54O₂ and Na_0.46Ni_0.13Fe_0.13Mn_0.54O₂ doped with certain number of iron ions, were synthesized by the sol-gel method under the same conditions and at the same calcination temperature, with sodium carbonate as the sodium source. The differences in the structure and properties of these two materials were further discussed. And their crystal structure and microstructure were observed by X-ray diffraction and scanning electron microscope. Electrochemical tests were carried out of the batteries made from these composite materials. The results showed that the material without Fe element, namely S1: Na_0.46Ni_0.26Mn_0.54O₂, was presented in P2-type structure and sheet-shaped with uniform particle size. Its structure, morphology and electrochemical performance were better than that of S2: Na_0.46Ni_0.13Fe_0.13Mn_0.54O₂.