The solid electrolyte Li3Fe2(PO4)3+Fe2O3 compound has been synthesized by solid state reaction and studied by Xray powder diffraction and impedance and Mössbauer spectroscopies.The XRD showed the presence of Li3Fe2(PO4)3 of monoclinic symmetry (space group P21) and confirmed the formation of the α-Fe2O3 (hematite). Two regions of the impedance dispersion have been analyzed in terms of the fast Li+ ions transport in the grains and grain boundaries of the ceramic samples. The temperature dependences of the grain conductivity, relaxation frequency, and permittivity showed anomalies related to α–β and β–γ structural phase transitions in Li3Fe2(PO4)3. As we found that in α and γ phases the activation energy of the grain conductivity is equal to the activation energy of the relaxation frequency in grain, which can be attributed to the mobility of fast Li+ ion in grains, the concentration of charge carriers remains constant with temperature.From Mössbauer spectroscopy, it is evident that Fe ions in the whole temperature range (10–690 K) are observed only in the Fe3+ state. Two phase transitions have been detected in this temperature range in the composite—the phase transition from the antiferromagnetic state to the paramagnetic one in Li3Fe2(PO4)3 and the Morin transition in hematite at temperatures TN=29.5 K and TM=235 K, respectively.