Enhanced electromagnetic wave absorption performance of MXene@CuCo₂S₄ heterostructures achieved by optimizing flower-like CuCo₂S₄ configuration

Ultrathin, lightweight and highly efficient electromagnetic wave (EMW) absorption materials are required to address escalating EMW pollution. MXene is a promising EMW absorber owing to its distinctive structure and plentiful terminating groups. However, the intrinsically high dielectric constants will cause impedance mismatch, hindering its EMW absorption. Herein, flower-like CuCo₂S₄ microspheres are fabricated and coupled with multilayered Ti₃C₂T_x MXene (MXene@CuCo₂S₄) to regulate its EMW absorption. The morphology of CuCo₂S₄ microspheres can be configured by regulating the molar ratios of Cu²⁺/Co²⁺ in precursors. Noticeably, the CuCo₂S₄ microspheres consisted of densely compacted narrow and thin nanosheets endow MXene excellent EMW absorption, exhibiting a minimum reflection loss of −60.02 dB and an effective absorption bandwidth (EAB) of 5.04 GHz with an absorber thickness of 1.61 mm. Increasing the thickness to 1.65 mm will extend the EAB to 6.02 GHz, covering the Ku band. Density functional theory reveals that electron transfer and orbital hybridization in MXene@CuCo₂S₄ heterostructures can induce charge redistribution and polarization. In addition, interfacial polarization, dipole relaxation, multiple scattering, and optimized impedance matching can synergistically enhance the EMW attenuation. Furthermore, the heterostructures can reduce radar cross-section, exhibiting excellent stealth capabilities. This work proposes a novel strategy for designing high-performance, lightweight MXene-based EMW absorbers.