Simultaneous development of well impedance matching and strong loss capability has become a mainstream method for achieving outstanding electromagnetic microwave absorption (EMWA) performances over wide temperature range. However, it is difficult to pursue both due to the mutual restraint of relationship between impedance matching and loss capability about temperature. Here, we propose a flexible regulation engineering of titanium nitride (TiN) nanofibrous membranes (NMs, TNMs), which could be distributed uniformly in the polydimethylsiloxane (PDMS) matrix and contributed to the formation of abundant local conductive networks, generating the local conductive loss and enhancing the loss ability of EMWs. Moreover, when the TNMs are used as functional units and dispersed in the matrix, the corresponding composites exhibit an outstanding anti-reflection effect on microwaves. As hoped, under the precondition of good impedance matching, local conductive loss and polarization loss together improve the loss capacity at room temperature, and polarization loss can compensate the local conductive loss to acquire effective dielectric response at elevated temperature. Benefiting from the reasonably synergistic loss ability caused by flexible regulation engineering, the corresponding composites exhibit the perfect EMWA performances in a wide temperature range from 298 to 573 K. This work not only elaborates the ponderable insights of independent membrane in the composition-structure-function connection, but also provides a feasible tactic for resolving coexistence of well impedance matching and strong loss capability issues in wide temperature spectrum.

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.

With the increasing advance of fifth generation (5G) network and the gradual expansion of digital devices, harsh working environment for electronic devices has spawned higher requirements for microwave absorbing materials (MAMs). Since both the electromagnetic response and energy conversion character vary with temperature, to achieve temperature insensitive microwave absorption behaviour in wide temperature range has become extremely challenging. In this work, structured metacomposites containing sub-wavelength reduced graphene oxide (RGO)@carbon spheres were fabricated, and the microwave absorption was further improved through structural and composition design of the RGO@carbon units. Due to the unique anti-reflection effect on microwave of the metacomposites, the temperature-insensitive electromagnetic performance at elevated temperature could be exhibited. Moreover, both the dielectric relaxation behaviour and microwave absorption proformance of the system could be further increased. As a result, the effective absorption bandwidth (reflection loss (RL) < −10 dB) of the metacomposites with only 3.0 wt.% filler content could cover the entire X-band (8.2–12.4 GHz) frequency ranging from 298 to 473K. The metacomposite proposed in this work provides a “de-correlating” strategy to break the linkage between microwave absorption behaviour and temperature, which offers an interesting plateau for fabricating efficient high-temperature microwave absorption structures with tunable and designable advantages.