Abstract
Electromagnetic wave interference has escalated into a pervasive global issue, driving intensified research efforts across both civilian and military domains. However, the development of advanced electromagnetic wave (EMW) absorbers with finely tunable dielectric and magnetic loss properties has emerged as a pivotal strategy for mitigating electromagnetic pollution. Herein, we propose a cation engineering strategy to tailor the absorption properties of ZIF-67-derived layered double hydroxide (LDH) composites through systematic substitution of Co(2+) with Fe, Mn, Zn, or Ni and stoichiometric control (Co/X = 1:4, 1:1). Mn/Zn doping enhances dipole polarization via lattice distortion, while structural analysis confirms that higher Co/X ratios preserve core-shell architectures, optimizing impedance matching. In contrast, Fe incorporation leads to excessive conductivity and impedance mismatch. The optimized CoNi1-4 composite exhibits superior broadband absorption (EAB = 4.52 GHz at 1.8 mm thickness, RL(min) = -24.5 dB), attributed to synergistic interface polarization and magnetic coupling. This study delivers a highly tailorable materials platform that enables a deeper fundamental understanding of the synergy between dielectric and magnetic loss processes, thereby offering new pathways for optimizing electromagnetic wave absorption.