Intelligent Off/On Switchable Microwave Absorption Performance of Reduced Graphene Oxide/VO2 Composite Aerogel

Intelligent microwave absorption (MA) materials possess the ability to dynamically change their microwave absorption performance, according to real-time requirements, and it is of great significance in future civil and military fields. For the first time, the reduced graphene oxide/VO2 composite aerogels are developed with off/on switchable MA performance, and the switchable mechanism is originated from the unique phase change behavior of VO2. As temperature increases (>68 degrees C), the VO2 displays the phase change from monoclinic to rutile phase, which accompanies with significant changes in aerogel's electrical conductivity as well as its permittivity, and consequently leads to off/on switchable MA performance. Particularly, two different off/on switch modes, on to off and off to on, can be separately realized by different composite aerogels as temperature increases, and this off/on switchable MA performance is also confirmed with good cycling stability. More importantly, during the off/on switch process, the maximum changes for the effective absorption bands (Delta EAB) and RL values (Delta RL) can be as high as 7.27 GHz and 49 dB, which exceeds most current reports. Besides, the RCS simulations on aircrafts have been performed and verified this intelligent MA performance, thus providing useful guidance for next-generation smart electromagnetic devices in various fields.

Automated summary

Intelligent microwave absorption materials with dynamically adjustable microwave absorption performance have great significance in future civil and military applications. A new type of reduced graphene oxide/VO2 composite aerogels has been developed, which exhibits switchable microwave absorption performance based on the phase change behavior of VO2. The electrical conductivity and permittivity of the composite material change significantly with temperature, resulting in off/on switchable microwave absorption performance. The composite material can switch between two modes, on to off and off to on, as temperature increases, and it demonstrates good cycling stability. Moreover, the maximum changes in effective absorption bands and RL values during the switch process exceed most current reports.