Multi-mechanism response of molten salt-modified MXene with NiCo₂O₄ nanosheets for enhanced electromagnetic wave absorption performance

To obtain even superior electromagnetic wave (EMW) absorption materials, research is currently focused on composite absorbers. The aim of this work is to prepare composite absorbers with multiple absorption mechanisms using 2D porous Ti₃C₂T_x MXene as a substrate. Here, porous Ti₃C₂T_x MXene nanosheets with a large layer spacing were formed through high-temperature molten salt treatment of layered Ti₃C₂T_x MXene nanosheets. Then, NiCo₂O₄ nanosheets were anchored onto the porous Ti₃C₂T_x MXene nanosheets through heat treatment, forming a heterogeneous structure of porous Ti₃C₂T_x MXene/NiCo₂O₄ (P-MXene/NiCo₂O₄). The heterogeneous interface between Ti₃C₂T_x MXene and NiCo₂O₄ nanosheets forms strong interfacial polarization, while NiCo₂O₄ connects the MXene layer to layer forming a conductive network structure. Furthermore, NiCo₂O₄ nanosheets suppress the self-stacking of porous Ti₃C₂T_x MXene nanosheets and improve impedance matching. As a result, P-MXene/NiCo₂O₄ offers excellent EMW absorption performance with a reflection loss (R_L) value of − 64.7 dB at a matching thickness of 4.465 mm. This study provides a new idea for pretreating Ti₃C₂T_x MXene and constructing efficient composite absorbing materials for electromagnetic waves.