Dielectric and microwave absorption properties of LiCoO₂ and its enhancement by micro-doping with metal ions

LiCoO₂ powders are the popular active cathode material in lithium batteries, but their dielectric and microwave absorption properties were seldom reported. In this work, the LiCoO₂ powders were synthesized by solid-state reaction. And in order to enhance their dielectric properties, influence of metal ions micro-dopant on the electromagnetic property of LiM_0.94Co_0.06O₂ powders (M = Mg, Zn, Ni, Mn and Y) was investigated. The phase and composition were characterized. The dielectric properties and the microwave absorption properties were evaluated. Compared to dopant of Zn, Ni, Mn and Y ions, the results showed that both the real part (ε′) and imaginary part (ε″) of LiM_0.94Co_0.06O₂/paraffin mixtures were obviously increased by doping Mg ions. One layer absorbent with 75 wt% LiMg_0.06Co_0.94O₂ content of a thickness of 1.8 mm had the optimum microwave absorption properties. The lowest reflection loss was − 36.6 dB. The results indicated that LiCoO₂ and LiM_0.06Co_0.94O₂ powders would be a possible candidate for microwave absorption materials.