Hierarchical bionic neural network-like architecture towards high- performance microwave absorption and corrosion protection

It remains challenging to develop multifunctional electromagnetic wave (EMW) absorbers to enhance the environmental adaptability and survivability of target devices in harsh environment. Herein, this study innovatively constructs a three-dimensional (3D) hierarchical bionic neural network-like Ni 3 Fe@N-doped carbon nanotube@Carbon foam (Ni 3 Fe@NCNT@CF) composite via dip-coating and carbonization operation, realizing the integration of microwave absorption and corrosion protection. The optimal Ni 3 Fe@NCNT@CF composite demonstrates competitive EMW absorption with a minimum reflection loss of −51.5 dB and a maximum effective absorption bandwidth (EAB) of 6.4 GHz at 10 wt%, due to superior interlinked conductive channels (with flexible and adjustable conduction loss) and magnetic-dielectric matching of the 3D hierarchical bionic neural network, including 3D CF skeleton (matrical neural network), short CNTs network (enrich “dendrites”), and ultra-long CNTs network (enhance “axons”). Besides, Ni 3 Fe@NCNT@CF composite exhibits a reliable anti-corrosion performance with a low corrosion current density ~10 -8 A·cm -2 after 30 days of immersion in corrosive medium, owing to the physical shield provided by the impermeable, inert CNT shells and carbon foam. Our findings may provide design inspiration of versatile EMW materials for applications in complicated environments.