LiCo_xNi_1−xO₂ with high dielectric and microwave absorption performance in X-band

In this study, we initially report the effect of lithium cobalt oxide (LiCoO₂) doped with different Ni ion contents on the dielectric and microwave absorption properties. Pure phases of LiCo_xNi_1−xO₂ (x = 0.2, 0.4, 0.6 and 0.8) have been synthesized using a solid-state reaction. Both the permittivity and permeability values of the LiCo_xNi_1−xO₂ composites distinctly shifted with increasing Ni-doping content. The result indicates that the LiCo_0.4Ni_0.6O₂ composite exhibits appropriate permittivity, which can be attributed to the increasing Ni ion distribution and distortion lattice volume. Further, the εʹ and εʹʹ values of LiCo_0.4Ni_0.6O₂ composite are 3.5 and 35 times higher than that of the LiCo_0.8Ni_0.2O₂ composite. The minimum reflection loss and wide absorption band can be obtained by calculating reflection loss of the LiCo_xNi_1−xO₂ composites with various compositions (x) and thicknesses. The optimum reflection loss value of the LiCo_0.4Ni_0.6O₂ composite is −46 dB with a thickness of 2.6 mm at 8.63 GHz, and the absorber bandwidth (RL < −5 dB) covers all the investigated frequency. LiCo_xNi_1−xO₂ could be a good candidate to become an efficient novel absorbent.