Multifunctional C/TiO₂ from MXene/Polyaniline for Electromagnetic Protection and Supercapacitor

Enormous endeavors have been made to cope with microwave pollution and energy crisis. Here, porous nitrogen-doped C/TiO₂ composites with absorption/shielding/supercapacitor functions were derived from MXene/polyaniline. It was discovered that KOH acted as porogen and had an etching–bridging–reaction effect during the activation process. As a microwave absorber, the composite/paraffin with a filler loading of 16 wt% reaches a minimum reflection loss of −52.8 dB and an effective absorption bandwidth of 4.72 GHz. Moreover, microwave absorption can be maintained within 45 days in air. Compared with untreated MXene, the absorber shows long-term functional stability in an oxygen-containing environment. As for electromagnetic interference shielding, the composite/paraffin at a filler loading of 50 wt% achieves 30.5 dB from 8.0 to 12.4 GHz. Additionally, the heterostructure delivers a desirable specific capacitance of 1,096.3 F g⁻¹ at 0.5 A g⁻¹. The trifunctional characteristics enrich the application trials of MXene derivatives and satisfy the strong need for versatile materials.