Boosted microwave absorption performance of transition metal doped TiN fibers at elevated temperature

Due to the temperature and frequency response of electromagnetic (EM) loss, how to realize the effective design of microwave absorption materials (MWAMs) at elevated temperature is highly desirable for practical applications. Herein, transition metal-doped titanium nitride (M-TiN, M = Fe or Co) fibers were fabricated, the distortion of TiN lattice could cause the adjustable charge enrichment, which played a profound influence on the dielectric response and EM microwave absorption (EMWA) performances. Benefiting from the negative correlation between dielectric loss and temperature, more loss mechanism could be introduced, which would effectively enhance dielectric loss and EMWA performances at elevated temperature. The optimal EMWA performances of Fe-TiN fibers/polydimethylsiloxane (PDMS) composites were realized with a wide temperature range (298–423 K): the reflection loss (RL) could reach 99% (RL < −20 dB) at 12.2 GHz with 1.8 mm, when the filler content was only 15.0 wt.%. Compared with the undoped-TiN fibers/PDMS and Co-TiN fibers/PDMS composites, the excellent EMWA of Fe-TiN fibers/PDMS composite could be attributed to the reasonably synergistic polarization loss and conduction loss. Based on systematic analysis of the variable-temperature EM parameters and EMWA performances, the optimization of EMWA performances in wide temperature domain could be realized by introducing appropriate polarization loss and its compensating. Hopefully, this work provides a new strategy for regulating the dielectric response and designing effective MWAMs at elevated temperature.