X-ray photoelectron and broadband impedance spectroscopy of Li1+4xTi2-x(PO4)3 solid electrolyte ceramics

Abstract

Li_1+4xTi_2-x(PO₄)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+4xTi_2-x(PO₄)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.