Ultra-Light Nanocomposite Absorbers of Prussian Blue Analogue/Ni Nanocubes Decorated Reduced Graphene Oxide for Tunable Dielectric Properties and Microwave Absorption

Microwave absorbers with the Prussian blue analogue (PBA)/Ni nanocubes decorated reduced graphene oxide (RGO) nanosheet nanocomposites were fabricated by a one-step hydrothermal reduction method, aiming to investigate the effect of weak/strong polar assembly on the dielectric properties, impedance, and microwave absorbing performance in 1–18 GHz. By varying the ratio of PBA/Ni nanocube and RGO, the nanocomposites exhibit the tunable permittivity in a wide range through the modulation of the distributing density of the weak polar PBA nanocubes on the strong polar RGO nanosheets. Based on the magnetic attenuation supported by Ni on the PBA, the calculated impedance and reflection loss (RL) imply the tunable microwave absorbing properties and bandwidth in the C-Ku band. Using the suitable nanocube/RGO ratio, the minimum RL of the nanocomposites can achieve −43.5 dB at 2.2 GHz of the S band with an absorber thickness of 9.7 mm, while the widest effective absorption bandwidth (RL < −10 dB) arrived 5.0 GHz in the Ku band with a much thinner thickness of 1.9 mm. This work provides a simple design for the lightweight tunable MOF-based microwave absorbers.