Porous metal microsphere M@C-rGO (metal = Mn, Fe, Co, Ni, Cu) aerogels with high low-frequency microwave absorption, strong thermal insulation and superior anticorrosion performance

Abstract

Nowadays, the development of multifunctional electromagnetic wave absorbers to improve the survivability of military equipment in complex environments is becoming a significant and unavoidable challenge. Here, three-dimensional porous metal microsphere@chitosan reduced graphene oxide (M@C-rGO, M = Mn, Fe, Co, Ni, Cu) aerogels are constructed via a simple ice template method and subsequent pyrolysis. The embedding of different metal microspheres realizes the modulation of the electromagnetic parameters of the synthesized aerogel, achieving a balance between attenuation capability and impedance matching. As expected, the synthesized Cu@C-rGO aerogel exhibits strong microwave absorption in the C-band with a minimum reflection loss (RL_min) of −59.28 dB, which also features an effective absorption bandwidth (EAB) of 6.32 GHz in the high-frequency band. Furthermore, the synthesized aerogels have superior radar stealth, thermal insulation and anticorrosion properties. Typically, the thermal conductivity of Cu@C-rGO is 0.0339 W m⁻¹ K⁻¹, and the charge transfer resistance (R_ct) is 1.421 × 10⁵ Ω cm². Impressively, more than 90% of the EAB could be retained after 7 days of corrosion in NaCl solution. Consequently, this work provides valuable guidance and insight into the development of multifunctional electromagnetic wave absorbers.