Hollow CuS microflowers anchored porous carbon composites as lightweight and broadband microwave absorber with flame-retardant and thermal stealth functions

At present, the development of lightweight and wideband microwave absorbing materials with stable infrared stealth property and adaptable to complex environments has become the key to multi-modal stealth technology. Herein, hollow CuS microflowers were self-assembled on biomass-derived porous carbon in situ to realize the multifunctions of microwave absorption, flame retardance and thermal stealth. The multicomponent synergistic effect combined with unique microarchitecture triggered the multiple polarization effects, multiple reflection and scattering as well as conduction loss in the PC@CuS composite. As a result, the PC800@CuS sample exhibited an optimal RLmin of −61.5 dB and an exceptionally wide EAB of 7.8 GHz with the filling ratio of only 10%. In addition, the PC@CuS composite also exhibited superior flame-retardant properties by virtue of its distinctive porous structure. Meanwhile, the uniform distribution of CuS particles played a vital role in enhancing the overall infrared absorption efficiency, thereby obtaining stable and highly-effective infrared stealth performance comparable to commercial products. This work shed light on the development of high-efficiency MAs with multifunctions in a facile and low-cost manner.