Impedance-matched (hydroxylated nano-BN/reduced graphene oxide) @Fe3O4/polyaniline composite for efficient microwave absorption and thermal management.

A microwave absorbing composite material with good thermal conductivity has been prepared to solve the problem of electromagnetic wave pollution in high-power density electronic equipment without increasing the heat load of the equipment. Herein, we prepared the quaternary absorbing material hydroxylated boron nitride nanosheets (BN-o)/reduced graphene oxide (r-GO) @Fe 3 O 4 @polyaniline (PAn) (BCFA) and adjusted the content of PAn to enhance the impedance matching and modulate the microwave absorption effect. At a PAn content of 40 wt%, the absorber exhibits admirable microwave absorption performance, the lowest reflection loss (RLmin) of −54.72 dB and effective microwave absorption bandwidth (RL < −10 dB, EAB) of 3.12 GHz at a thickness and frequency of 3.5 mm and 7.2 GHz, respectively. The excellent microwave absorption is due to a suitable mechanism of dielectric and magnetic losses and the excellent impedance matching of the absorber. Moreover, the high thermal conductivity and phonon transport properties of the BN-o/r-GO van der Waals heterostructure give the composite thermal conductivity of 1.69 W(m·K)−1 when the BN-o/r-GO content is approximately 14 wt%. Therefore, BCFA has become a candidate material to solve the electromagnetic pollution problem of high-power density electronic equipment. [Display omitted] • The research highlights of this paper are list below: • The core-shell BN-o/r-GO@Fe 3 O 4 @PAn nanocomposite with dual functions was prepared. • The RL min of the BN-o/r-GO@Fe 3 O 4 @PAn can reach −54.72 dB, and the EAB is close to 3.12 GHz. • The thermal conductivity of BN-o/r-GO@Fe 3 O 4 @PAn reaches 1.69 W(m·K)−1 when the BN-o/r-GO content is approximately 14 wt%. [ABSTRACT FROM AUTHOR]