X-ray photoelectron and broadband impedance spectroscopy of Li_1+4<i>x</i>Ti_2-<i>x</i>(PO₄)₃ solid electrolyte ceramics

Abstract

Li 1+4x Ti 2-x (PO 4 ) 3 (where x = 0.2, 0.5) compounds were synthesized by solid state reaction, and ceramics were sintered. The structure of compounds was studied by X-ray diffraction. Elemental compositions and binding energies of Ti 2p, P 2p, O 1s, and Li 1s core level at the surfaces of Li 1+4x Ti 2-x (PO 4 ) 3 ceramics were determined by energy dispersive X-ray spectrometer (EDX) and X-ray photoelectron spectroscopy (XPS). Impedance spectroscopy of the ceramics was performed in the frequency range of 10 Hz-1 MHz by the four-electrode method and in the frequency range of 1 MHz -3 GHz by the microwave impedance spectrometer. The measurements of electrical properties of the ceramics were carried out in the temperature interval of (300-700) K. The increase of the stoichiometric factor x of the compounds leads to the increase of bulk conductivities and values of dielectric permittivity.