Old molybdenum blue for new application: {Mo₇₂X₃₀}/PANI/MWCNTs (X = Fe, V) ternary coaxial cable-like fibers for superior electromagnetic wave absorption

The systematic design of heterointerfaces has been a topic of considerable attention in electromagnetic absorption applications. For the first time, molybdenum blue/polyaniline/multiwalled carbon nanotubes ({Mo₇₂X₃₀}/PANI/MWCNTs, X = Fe, V) ternary coaxial cable-like fibers are systematically designed and synthesized via host–guest electrostatic and synergistic effect and employed as exceptional electromagnetic wave absorbers. The coaxial cable-like structure features an abundance of heterointerfaces between layers, which improves dipole polarization and interface polarization effect, and regulates conductive loss. In addition, the inclusion of polyoxometalates boosts magnetic losses dominated by eddy current losses and improves impedance matching. The optimal {Mo₇₂V₃₀}/PANI/MWCNTs exhibit higher electromagnetic wave absorption (−48.12 dB) at a thinner thickness (2.3 mm). At a thickness of 2.5 mm, {Mo₇₂Fe₃₀}/PANI/MWCNTs exhibit the maximum effective absorption bandwidth (6.16 GHz). In addition to expanding our understanding of the effect of heterointerfaces on electromagnetic absorption, this study demonstrates the potential utilization of polyoxometalate functional molecules in the electromagnetic wave absorption field.