Mass fabrication and superior microwave absorption property of multilayer graphene/hexagonal boron nitride nanoparticle hybrids

Graphene has been regarded as a promising candidate in microwave absorption field but still faces some major challenges, including the limitation of mass production and poor impedance matching. Here, we demonstrate a simple approach to fabricate multilayer graphene in a kilo-mass/hour (≥2.5 kg/h) scale through an oxidation-thermal expansion-air convection shearing process. The subsequent incorporation of hexagonal boron nitride nanoparticles (h-BNNPs) can effectively tailor the dielectric and magnetic properties of the as-obtained multilayer graphene, which can significantly boost its microwave absorption performance. The as-obtained multilayer graphene/h-BNNP hybrid with 40 wt.% of h-BNNPs, exhibits extremely low reflection loss value of −67.35 dB at 8.04 GHz when the absorber thickness is 3.29 mm, ranking it as one of the most attractive absorbers reported to date. Moreover, the multilayer graphene/h-BNNP hybrids possess low densities less than 0.45 g/cm3, making them very attractive for practical microwave absorption application.