Dual template induced assembly of 2D nanosheets to 3D porous Mo2C/NiFe-NC networkers for electromagnetic wave absorption

Abstract

Developing high-performance materials with ultrathin matching thickness for electromagnetic wave absorption (EMW) is essential for the commercialization of electromagnetic devices, but it is still formidably challenging. In this work, Mo2C/NiFe-NC networker with small Mo2C grains, NiFe alloy coated by graphitized carbon (NiFe-NC), and N-doped carbon matrix are constructed by free-drying and dual template strategy. With the assistance of hard template (salt, NaCl)) and soft template (urea), the ultrathin 2D layered carbon nanosheets produced by pyrolysis are assembled into a 3D hierarchical porous network. The designed Mo2C/NiFe-NC networker exhibits a hierarchical porous structure, 3D network skeleton, heterogeneous interface, abundant heteroatom doping, and magnetic NiFe alloy, which inherits good dielectric loss (dipole polarization, interfacial polarization, and conduction loss), magnetic loss (natural resonance and exchange resonance) and considerable impedance matching characteristics. Impressively, the well-designed Mo2C/NiFe-NC networker enables a reflection loss (RL) value of −51.56 dB at an ultrathin matching thickness of 1.4 mm. Furthermore, the effective absorption bandwidth (EAB, RL ≤ −10 dB) is up to 3.7 GHz. Importantly, the EAB in the matching thickness range of 1–5 mm is as high as 14.6 GHz, covering the entire C-band, X-band, and Ku-band. This work may open a key avenue for high-performance EMW absorption materials via a dual template assistance strategy.