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 Ti3C2Tx MXene as a substrate. Here, porous Ti3C2Tx MXene nanosheets with a large layer spacing were formed through high-temperature molten salt treatment of layered Ti3C2Tx MXene nanosheets. Then, NiCo2O4 nanosheets were anchored onto the porous Ti3C2Tx MXene nanosheets through heat treatment, forming a heterogeneous structure of porous Ti3C2Tx MXene/NiCo2O4 (P-MXene/NiCo2O4). The heterogeneous interface between Ti3C2Tx 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 Ti3C2Tx MXene nanosheets and improve impedance matching. As a result, P-MXene/NiCo2O4 offers excellent EMW absorption performance with a reflection loss (RL) value of − 64.7 dB at a matching thickness of 4.465 mm. This study provides a new idea for pretreating Ti3C2Tx MXene and constructing efficient composite absorbing materials for electromagnetic waves.