Novel hierarchical RGO/MoS2/K-αMnO2 composite architectures with enhanced broadband microwave absorption performance

Here we report the successful preparation of hierarchical structures of reduced graphene oxide/molybdenum disulfide/potassium-alpha manganese dioxide (RGO/MoS2/K-alpha MnO2) composites via an improved hydrothermal method. The obtained composites display unique ternary architectures in which uniform K-alpha MnO2 nanospheres as antennas are distributed on the surface of RGO/MoS2 composites. The minimum reflection losses (RL) of MoS2, RGO/MoS2 and RGO/MoS2/K-alpha MnO2 in the frequency of 2.0-18.0 GHz are -7.8 dB, -21.7 dB and -71.7 dB with a thickness of 8.0 mm, 1.8 mm and 3.8 mm, respectively. Moreover, the RL values of RGO/MoS2/K-alpha MnO2 composites exceeding -20 dB have been achieved in broad frequency bands of 2.5-18.0 GHz. The addition of K-alpha MnO2 adjusts the balance between epsilon(r) and mu(r) of the composites, resulting in a larger alpha value and a higher matching impedance ratio. The excellent microwave absorption performance of the ternary composites mainly originates from a particular hierarchical antenna-like structure, good impedance matching, polarization relaxation, and the efficient complementarities between RGO/MoS2 and K-alpha MnO2. Finally, this RGO/MoS2/K-alpha MnO2 composite with strong absorption and wide frequency will be a promising material in the field of microwave absorption.