Graphene\nShield by SiBCN Ceramic: A\nPromising High-Temperature Electromagnetic Wave-Absorbing Material\nwith Oxidation Resistance

Abstract

As cutting-edge emerging electromagnetic (EM) wave-absorbing materials,\nthe Achilles’ heel of graphenes is vulnerable to oxidation\nunder high temperature and oxygen atmosphere, particularly at temperatures\nmore than 600 °C. Herein, a graphene@Fe₃O₄/siliconboron carbonitride (SiBCN) nanocomplex with a hierarchical\nA/B/C structure, in which SiBCN serves as a “shield”\nto protect graphene@Fe₃O₄ from undergoing high-temperature\noxidation, was designed and tuned by polymer-derived ceramic route.\nThe nanocomplexes are stable even at 1100–1400 °C in either\nargon or air atmosphere. Their minimum reflection coefficient (RC_min) and effective absorption bandwidth (EAB) are −43.78\ndB and 3.4 GHz at ambient temperature, respectively. After oxidation\nat 600 °C, they exhibit much better EM wave absorption, where\nthe RC_min decreases to −66.21 dB and EAB increases\nto 3.69 GHz in X-band. At a high temperature of 600 °C, they\nalso possess excellent and promising EW wave absorption, for which\nEAB is 3.93 GHz, covering 93.6% range of X-band. In comparison to\nprevious works on graphenes, either the EAB or the RC_min of these nanocomplexes is excellent at high-temperature oxidation.\nThis novel nanomaterial technology may shed light on the downstream\napplications of graphenes in EM-wave-absorbing devices and smart structures\nworked in harsh environments.