Liquid Metal@Reduced Graphene Oxide Composite Putty for Microwave Absorption

The development of radar technology has increased the possibility of warplanes being detected. Therefore, radar stealth capability is critical for warplanes. Currently, microwave-absorbing materials with plasticity are urgently needed to reduce the strong electromagnetic scattering from plenty of small gaps on aircraft. Here, we propose a strategy to encapsulate liquid metal with reduced graphene oxide (rGO) to form a plastic microwave-absorbing putty. The putty is formed by a self-assembly electrostatic method to create a sparse foam structure with good plasticity. Interestingly, the nonmagnetic putty not only shows a dielectric loss but also exhibits unique magnetic losses. This synergistic mechanism allows the putty to obtain a minimum reflection (RLmin) of −58.86 dB at 8.93 GHz with a small thickness of 3.57 mm. The excellent properties of this composite putty allow it to be a candidate for microwave-absorbing putties to reduce the radar cross section of airplanes.