Fabrication of Core‐Shell ZnO‐ / CoNi ‐Layered Double Hydroxide@Polypyrrole Composites for Excellent Electromagnetic Wave Absorption

Abstract

ABSTRACT Multi‐interface materials have emerged as a key focus in developing advanced electromagnetic wave absorbers. This study introduces a novel composite of core‐shell ZnO/CoNi‐layered double hydroxide@polypyrrole (ZnO/CoNi‐LDH@PPy), demonstrating superior electromagnetic wave absorption. Thanks to the appropriate composition and ratio, the minimum reflection loss ( RL min ) of ZnO/CoNi‐LDH@PPy composites is −72.77 dB at 5.56 GHz with the matched thickness of 4.64 mm, and the effective absorption bandwidth (EAB) is up to 6.16 GHz when the matched thickness of 2.11 mm is adjusted to cover the whole Ku band. These enhancements stem from synergistic effects between interfacial polarization, conductive loss, and optimized impedance matching. This innovative design effectively addresses the long‐term challenge of performance deterioration due to secondary phase separation in traditional LDH‐based absorbers, while also enhancing the overall structural stability of the composite material system.