Study on Mössbauer Spectrum and Magnetic Properties of Al2O3 and Lifepo4/C Composite Materials

Abstract

Al₂O₃ and LiFePO₄/C composite materials were prepared by two-step sol-gel. Iron valence, phase structure, microscopic surface morphology and magnetic properties of Al₂O₃ and lithium iron phosphate carbon composite materials were studied by Mössbauer spectrum, XRD, SEM and VSM methods. The phase structure analysis of the composite materials showed that all samples appeared the lithium iron phosphate and Al₂O₃ main peaks and no obvious impurity peaks. The micromorphic analysis showed that the particle quality of composite materials is obvious, the dispersion is better, and the particle size is mainly 400 nm. Hysteresis loop test at room temperature indicated that the introduction of alumina caused the saturation magnetization strength Ms (emu/g), the coercivity Hc (Oe) and the residual magnetization strength Mr (emu/g) to change, and the above parameters have the same trend of change, while increasing or decreasing at the same time. Mössbauer spectrum research shows that the ISOMER SHIF of the composite at x=0.00 is equal to 1.22831573mm/s. This indicates that there is the high spin Fe²⁺, and there is no high spin Fe³⁺. The Doublet(1) fit of all composite materials accounts for more than 70%, indicating that the main component of all composites is a high spin Fe²⁺ compound.