Construction of polyaniline-coated 3D peony flower-like Bi2O2CO3 heterogeneous interface for synergistically boosting the microwave absorption

Morphology and composition designs are recognized as effective strategies for realizing efficient microwave absorption performance through a synergistic coupling mechanism that involves microwave loss capability, impedance matching, multiple reflection and scattering. Constructing heterointerfaces can effectively improve the polarization loss, thereby enhancing the microwave absorption of dielectric materials. In this work, a peony flower-like Bi 2 O 2 CO 3 (BOC) is synthesized from Bi 2 O 3 precursor, and its morphology is manipulated by controlling the crystal structure of Bi 2 O 3 . Subsequently, the peony flower-like BOC is coated by polyaniline (PANI) via an in-situ polymerization to form peony flower-like BOC@PANI composites. Electromagnetic parameters of these composites can be effectively regulated by changing the mass ratio of BOC and PANI, resulting in tunable impedance and tunable polarization/conductive loss capacities. Furthermore, the peony flower‑like structure and the heterogeneous interface between BOC and PANI promote multiple reflection and scattering of microwave, thereby prolonging their transmission path, while also enhancing interface polarization, which contributes to improved polarization loss. Accordingly, peony flower-like BOC@PANI-2 composite exhibits a minimum reflection loss of −57.11 dB at 1.82 mm and an effective absorption bandwidth of 5.74 GHz at 1.89 mm. Radar cross-section simulation demonstrates that BOC@PANI-2 has the weakest radar scattering signals, indicating a significantly improved stealth effect.