Vertically Aligned Recycled Carbon Fibre/MXene Composites for Impedance-Regulated Microwave Absorption and Thermal Management.

Recycled carbon fibres offer a promising sustainable route to functional composites, but their short length and disordered connectivity limit controlled electromagnetic and thermal transport. Here we use electrostatic flocking to construct vertically aligned rCF@Ti3C2Tx/NiFe2O4 arrays within a polydimethylsiloxane (PDMS) matrix inspired by the hierarchical host-symbiont of marine sponges. The aligned architecture redistributes conductive pathways and interfacial polarization, improving impedance matching while providing through-plane heat transport channels. Compared with the randomly dispersed composite, the vertically aligned composite at the same loading ratio deepens the minimum reflection loss (RLmin) from -33.62 to -60.71 dB. The Effective absorption bandwidth (EAB) broadens increase from 3.91 to 7.82 GHz. In thermal-transport comparison, vertical alignment raises the through-plane thermal conductivity from 0.18 to 4.03 W m- 1 K- 1. These results suggest that alignment control is an effective route to upcycle short recycled fibres into multifunctional polymer composites.