Low Weight, low thermal Conductivity, and highly efficient electromagnetic wave absorption of Three-Dimensional Graphene/SiC-nanosheets aerogel

Abstract

With the rapid development of modern information technology, high-level electromagnetic wave (EMW) absorbing materials are playing an increasingly important role in military and civilian fields. However, current EMW absorbers usually have narrow absorption bandwidths and low absorption strengths, which hinder their practical applications. Herein, lightweight aerogels with low thermal conductivity and highly efficient EMW absorption were fabricated via a sol–gel method and subsequent carbothermal reduction with a simple chemical reaction process. The as-prepared graphene/SiC-nanosheets aerogels are composed of a large number of the interconnected two-dimensional SiC nanosheets and graphene sheets with abundant micrometer-sized pores that favored impedance matching, which endows the aerogels with outstanding EMW-absorbing performance. Conductive loss and interfacial polarization further promote the EMW-absorbing of the graphene/SiC-nanosheets aerogels. In addition, the highly porous and interconnected three-dimensional graphene/SiC-nanosheets aerogel networks not only facilitate the absorption of infiltrated EM waves via multiple reflection but also effectively reduce the number of heat transmission routes in the aerogels. The as-prepared SiC/G-2 aerogel exhibites excellent EMW-absorbing property, with a RLmin of −65.08 dB at a frequency of 13.20 GHz, a thickness of 3.5 mm and an EAB of 2.21 GHz. These results demonstrate that the as-prepared graphene/SiC-nanosheets aerogel is fascinating material with possible applications in high-performance EMW-absorbing and heat-insulating in the aviation and aerospace fields.