Controllable preparation and electromagnetic wave absorption performance of compressible graphene aerogels

Abstract

In this study, an easy-operation developed method was adopted to generate ultralight and compressible graphene aerogels by using graphene oxide and ammonia. By changing the process parameters, such as reduction temperature, reducing agent content and ammonia concentration, the variation laws of density and pore size of aerogel were obtained, which was conducive to realizing the controllable preparation of aerogel structure. The prepared graphene aerogel has good compressive performance and its density can reach 5.26 mg/cm³. Though repeatedly compressed 200 times under the load that is 4000 times as large as its own weight, it still maintained the structural integrity and mechanical properties. An ideal model of three-dimensional graphene aerogel was constructed, and the electromagnetic wave absorption performance was simulated by computer simulation technology (CST) microwave studio. The results show that when the thickness, pore size and height of the sheet are 1.4 mm, 5 mm and 14 mm respectively, the optimal electromagnetic wave absorption effect of −31.08 dB can be obtained, and the effects of thickness, pore size and height of the sheet on the electromagnetic wave absorption performance are revealed, which provides a reference for the structural design of aerogel with both compressibility and electromagnetic wave absorption performance.