Ligand engineering strategy regulating magnetic-dielectric loss in Ni/C nanocomposites for electromagnetic wave absorption

Magnetic-dielectric synergy is critical to the electromagnetic wave absorption (EWA) performance of carbon/metal absorbers and is closely related to their nanoscale structure. In this work, aromatic dianhydrides with different conjugation lengths (PMDA, NTDA, and PTCDA) were used for ligand engineering of phthalocyanine-derived Ni/C nanocomposites, yielding Ni/C-PMDA, Ni/C-NTDA, and Ni/C-PTCDA. The resulting nanostructural variation regulated carbon ordering, Ni dispersion, and interfacial coupling at the Ni/C heterointerface, thereby redistributing dielectric and magnetic loss behavior. As a result, Ni/C-PMDA shows deep absorption with a reflection loss of −53.30 dB at 2.99 mm, while Ni/C-NTDA achieves a wide effective absorption bandwidth of 6.00 GHz at a thin thickness of 1.92 mm. Moreover, far-field radar cross section simulations on a Ni/C nanocomposite-coated perfect electric conductor (PEC) plate show reduced scattering compared with bare PEC. This work offers a ligand engineering strategy for designing Ni/C nanocomposites with optimized magnetic–dielectric synergy for electromagnetic wave absorption.