XRD, impedance, and Mossbauer spectroscopy study of the Li3Fe2(PO4)3 + Fe2O3 composite for Li ion batteries

The synthesis procedure of the Li3Fe2(PO4)(3) + Fe2O3 composite is presented. The monoclinic (A type) and hematite phases were detected by X-ray diffraction after the synthesis of the composite. The structural alpha-beta (at a temperature of 460 K) and beta-gamma (at a temperature of 523 K) phase transitions in the composite were indicated by the anomalies of the electrical conductivity, dielectric permittivity, and changes of activation energies of conductivity. Two phase transitions have been detected in the Li3Fe2(PO4)(3) + Fe2O3 composite by Fe-57 Mossbauer spectroscopy: the phase transition in Li3Fe2(PO4)(3) from the paramagnetic to antiferromagnetic phase at temperature T (N) = 29.5 K and the Morin phase transition in Fe2O3 at temperature T (M) = 235 K.