Structure and Magnetic Properties of AO and LiFePO₄/C Composites by Sol-Gel Combustion Method

LiFePO₄ takes advantage of structure stability, safety and environmental friendliness, and has been favored by the majority of scientific researchers. In order to further improve the properties of LiFePO₄, AO-type metal oxides (MgO and ZnO) and LiFePO₄/C composites were successfully prepared by a two-step sol-gel method. The effects of AO-type metal oxides (MgO and ZnO) on LiFePO₄/C composites were studied. TG, XRD, FTIR, SEM and VSM analysis showed that the final product of the MgO and LiFePO₄/C composite was about 70.5% of the total mass of the precursor; the complete main diffraction peak of LiFePO₄ and MgO can be found without obvious impurity at the diffraction peak; there is good micro granularity and dispersion; the particle size is mainly 300 nm; the saturation magnetization (Ms), the residual magnetization (Mr) and the area of hysteresis loop are increased with the increase in MgO content; and the maximum Ms is 11.11 emu/g. The final product of ZnO and LiFePO₄/C composites is about 69% of the total mass of precursors; the complete main diffraction peak of LiFePO₄ and ZnO can be found without obvious impurity at the diffraction peak; there is good micro granularity and dispersion; the particle size is mainly 400 nm; and the coercivity (Hc) first slightly increases and then gradually decreases with the increase of zinc oxide.