Effects of Co2+ ion doping content on conductivities and microwave absorption properties of Li1.3+xAl0.3-xCoxTi1.7 (PO4)3 ceramics

Abstract

Li1.3+xAl0.3-xCoxTi1.7(PO4)3 (x=0, 0.04, 0.08, 0.12) ceramics were prepared by high temperature solid-state method. The effects of Co2+ ion doping content on the morphology, phase, ion conductivity, dielectric property and microwave absorption property were studied. Results show that Li1.3+xAl0.3-xCoxTi1.7(PO4)3 ceramics had cubic grains with relative densities of 90%, and they are single rhombohedral LiTi2(PO4)3 phase without any impurity. Li1.34Al0.26Co0.04Ti1.7(PO4)3 ceramic has the highest ionic conductivity of 1.14×10−3 S·cm−1. A lower valent cation occupying the Ti(Al) site can reduce the coulombic repulsion between Li+ ions and skeleton ions, and appropriate doping content can obtain suitable size of Li+ ions channel. Then, Li+ ion has a minimum activation energy of 0.29 eV, which is easy to generate thermal ion relaxation polarization. Therefore, Li1.34Al0.26Co0.04Ti1.7(PO4)3 ceramic also has the highest complex permittivity, ε' is 12.9-13.7 and ε" is 3.1-3.8. In addition, due to the combined effect of polarization loss and conductance loss, it has the optimum microwave absorption property of an absorption bandwidth covering the whole X-band and a minimum reflection loss of −17.3 dB at 9.67 GHz, which is a potential candidate of high-temperature lightweight microwave absorption material.

Keywords

• ion doping
• latp ceramics
• dielectric property
• microwave absorption property