Synergistically Assembled Cobalt-Telluride/Graphene Foam with High-Performance Electromagnetic Wave Absorption in Both Gigahertz and Terahertz Band Ranges

Electromagnetic wave (EMW)-absorbing materials have a great impact on civil use and national defense. In this paper, a novel composite, RGO@6CoTe2-300 (the mass ratio of reduced graphene oxide to CoTe2 is 1:6, annealed at 300 °C), has been obtained through a facile melt-diffusion method and solvothermal method. The as-prepared samples have shown excellent reflection losses (RL) and effective adsorption bandwidth (EAB) by controlling the loading of CoTe2 and the annealing temperature. The sample has exhibited a RL of −62.2 dB at 13.04 GHz with the matching thickness of 3.53 mm, and the EAB reaches 8.2 GHz at 2–18 GHz. Moreover, excellent terahertz (THz) absorption property is also obtained at 0.2–2.0 THz. A RL of 54.07 dB is acquired, and the EAB covers 100% of the entire measured bandwidth. Thus, RGO@6CoTe2-300 can be considered as a promising EMW absorption material in both gigahertz and terahertz band ranges.