Synthesis of three-dimensional graphene@nickel nanocrystals with high efficient microwave absorption

In recent years, the rapid advancement of military radar technology has driven the demand for electromagnetic wave absorbing materials that are thin, wide, lightweight and strong absorption. This study utilizes a combined method of solvothermal synthesis and high-temperature calcination to fabricate a super-elastic, three-dimensional (3D) graphene anchored with magnetic nickel nanocrystals (rGO@Ni). This one-step process simultaneously achieves the self-assembly of 3D reduced graphene oxide (rGO) and the in-situ loading of magnetic nickel nanoparticles without external reducing agents. The resulting rGO@Ni composite features a 3D porous network architecture with uniformly distributed spherical nickel nanoparticles (approximately 20 nm in diameter) anchored on the graphene sheets. Compared to pure rGO or nickel, the rGO@Ni composite demonstrates superior microwave absorption performance achieving a minimum reflection loss of − 53.14 dB at 16.55 GHz with a matching thickness of only 2.5 mm. Notably, its effective absorption bandwidth (below − 10 dB) reaches 7.99 GHz, covering the frequency range from 10.01 to 18 GHz.