摘要
Al_2O_3-coated spinel LiMn_2O_4 cathode materials, presintered LiMn_2O_4(P-LMO), and calcined LiMn_2O_4(C-LMO) were synthesized by chemical deposition and thermal treating method using presintered and calcined LiMn_2O_4 as precursors. The crystal structure, morphology,the thickness of the coating layer, and particle size of prepared samples were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), high-resolution transmission electron microscopy(HRTEM), and Malvern instruments. The average particle size of P-LMO with like-spheres(0.3 μm) is much smaller than that of C-LMO(0.5 μm). The Al_2O_3 layer of P-LMO can effectively reduce the charge transfer resistance and inhibit the Mn dissolution. The electrochemical performance of P-LMO is better than that of C-LMO. It is found that the LiMn_2O_4 cathode materials have excellent electrochemical cyclability by coated 2 mol% Al_2O_3 at the surface of presintered material. The initial discharge capacity of the material with 2 mol% Al_2O_3-coated is 114.0 m Ah·g^(-1) at 0.1 C rate and 55 ℃, and the capacity retention is 87.3 % at 0.5 C rate.
Al_2O_3-coated spinel LiMn_2O_4 cathode materials, presintered LiMn_2O_4(P-LMO), and calcined LiMn_2O_4(C-LMO) were synthesized by chemical deposition and thermal treating method using presintered and calcined LiMn_2O_4 as precursors. The crystal structure, morphology,the thickness of the coating layer, and particle size of prepared samples were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), high-resolution transmission electron microscopy(HRTEM), and Malvern instruments. The average particle size of P-LMO with like-spheres(0.3 μm) is much smaller than that of C-LMO(0.5 μm). The Al_2O_3 layer of P-LMO can effectively reduce the charge transfer resistance and inhibit the Mn dissolution. The electrochemical performance of P-LMO is better than that of C-LMO. It is found that the LiMn_2O_4 cathode materials have excellent electrochemical cyclability by coated 2 mol% Al_2O_3 at the surface of presintered material. The initial discharge capacity of the material with 2 mol% Al_2O_3-coated is 114.0 m Ah·g^(-1) at 0.1 C rate and 55 ℃, and the capacity retention is 87.3 % at 0.5 C rate.
基金
financially supported by the Science and Technology Project of Hunan Province (No. 2010FJ4061)
the Technology Project of Changsha (No. K1201039-11)
