Dual-step Redox Engineering of Two-Dimensional CoNi-Alloy Embedded B, N-Doped Carbon Layers towards Tunable Electromagnetic Wave Absorption and Light-Weight Infrared Stealth Heat Insulation Devices.

Two-dimensional layered metallic graphite composites as promising electromagnetic wave absorption materials (EWAMs) for their combined properties of abundant interlayer free spaces, rich metallic polarized sites and high conductivity, but the controllable synthesis remains rather challenging. Herein, a dual-step Redox engineering strategy was developed by employing cobalt boron imidazolate framework (Co-BIF) to construct a two-dimensional CoNi-alloy embedded B, N-doped carbon layers (2D-CNC), as a promising EWAM. In the first step, a chemical etching oxidation process on Co-BIF was used to obtain an optimized 2D-CoNi-layered double hydroxide (2D-CoNi-LDH) intermediate and in the second, high-temperature calcination reduction was implemented to modify graphitization the degree of the 2D-CNC. The obtained sample delivers superior reflection loss (RL min ) of -60.1 dB and wide effective absorption bandwidth (EAB) of 6.24 GHz. The synergy mechanisms of interfacial/dipole polarization and magnetic coupling were in-depth evidenced by the hologram and Lorentz electron microscopy, revealing its significant contribution on multireflection and impedance matching. Further theoretical evaluation by COMSOL simulation in different fields based on the dynamic loss process towards the test ring reveals the in situ EW attenuation process. This work presents a strategy to develop multifunctional light-weight infrared stealthy aerogel with superior pressure-resistant, anti-corrosion and heat-insulating properties for future applications. This article is protected by copyright. All rights reserved.