Electrostatic self-assembly of hierarchical MXene-NiO nanowire aerogels: Multi-mechanism synergy for high-efficiency electromagnetic wave absorption

In response to the burgeoning challenge of electromagnetic wave pollution, the development of high-performance electromagnetic wave absorbing materials with strong attenuation capability is urgently needed. In this study, a MXene/NiO nanowire hybrid aerogel was constructed via electrostatic self-assembly, leveraging a multi-mechanism synergistic loss strategy to significantly enhance the electromagnetic absorbing performance. The three-dimensional conductive network of the material optimizes impedance matching, facilitating electromagnetic wave penetration into the interior for multiple reflections and scattering, thereby reducing surface reflection. Simultaneously, the highly conductive MXene contributes to substantial conduction loss, while abundant defects (graphitic defects, oxygen-containing groups) and heterogeneous interfaces (MXene-NiO) induce notable dipole and interfacial polarization losses. Furthermore, the nano-heterostructure formed between NiO nanowires and MXene enhances interfacial polarization through charge accumulation at the interfaces. Benefiting from these synergistic loss mechanisms, the optimized aerogel exhibits exceptional electromagnetic wave absorption performance, achieving a minimum reflection loss ( RL min ) of −53 dB at a thickness of 1.6 mm and an effective absorption bandwidth (EAB) of 4 GHz. Our findings propose an innovative materials design doctrine enabling precise multi-scale regulation of electromagnetic wave absorption in aerogels.