Porous nickel–zinc ferrite/polyaniline/polyimide composite based on improved impedance matching for electromagnetic microwave absorption

Abstract Excellent impedance matching plays a crucial role in the design of absorbers to tackle the growing problem of electromagnetism pollution. Here, a porous nickel–zinc ferrite/polyaniline/polyimide (NiZnFe₃O₄/PANI/PI) composite was prepared by in‐situ polymerization and thermally assisted non‐solvent‐induced phase separation (TNIPS). The impedance matching of porous NiZnFe₃O₄/PANI/PI composite can be improved by controlling the composition ratio of NiZnFe₃O₄/PANI absorbing filler. When the absorbing filler satisfied a molar ratio of 8:2 for Ni to Zn and a mass ratio of 2:8 for PANI to NiZnFe₃O₄, the porous NiZnFe₃O₄/PANI/PI composite with 20% absorbing filler content displayed the minimum reflection loss of −30.01 dB, effective absorption bandwidth of 4.05 GHz (6.91–10.96 GHz), and the impedance matching (Z) value almost equal to 1 at 9.36 GHz. In addition, the initial thermal decomposition temperature (T₅%) of porous NiZnFe₃O₄/PANI/PI composite beyond 544°C in nitrogen, demonstrates superior thermal stability properties. The porous NiZnFe₃O₄/PANI/PI composite in this research has great application potential in electromagnetic wave absorption at high‐temperature environment.