Electromagnetic interference shielding performance of lightweight aramid nanofiber/graphene composite aerogels

Abstract

Aramid nanofiber (ANF)/graphene (GN) composite aerogels were fabricated by the ice template and freeze-drying method. Because of the excellent electrical conductivity of GN and its good dispersibility in ANF dispersions, the ANF/GN composite aerogels possessed excellent electromagnetic interference (EMI) shielding performance as well as good compression performance and heat resistance. Moreover, the composite aerogels with ultralow density (0.04 g cm⁻³) exhibited a high EMI shielding effectiveness (SE) of 31.55 dB, and its specific EMI SE value reached 3878.78 dB cm² g⁻¹. The high porosity of the composite aerogel increases its impedance matching with air, and the main EMI shielding mechanism of the composite aerogels is microwave absorption. Besides, the composite aerogels had excellent thermal stability, and their 10 wt% weight loss temperature was higher than 500 °C in nitrogen. This work provides an easy approach to prepare lightweight ANF/GN composite aerogels with excellent EMI shielding performance.