MnO2 Intercalation-Guided impedance tuning of Carbon/Polypyrrole double conductive layers for electromagnetic wave absorption

Highly conductive materials (HCMs) exhibit substantial dielectric loss owing to their excellent electron-transporting properties and are potentially applicable in the field of electromagnetic wave absorption (EMA). However, attaining an ideal absorption performance is challenging when HCMs are used as electromagnetic wave-absorbing materials alone mainly because of the impedance mismatch caused by exaggerated complex permittivity, which prevents electromagnetic waves from entering the material and cause secondary pollution. To address this issue, we propose the construction of a separated dual conductive layer structure (SDC) for the first time. Petal-like MnO2 was inserted into the middle of carbon/polypyrrole (PPy) dual conductive layers to deliver the SDC absorber, polypyrrole@MnO2@carbon (PMC). The unique microstructure of MnO2 creates suf-ficient interior space between the carbon and PPy layers, allowing for electromagnetic waves to enter the HCMs, thereby promoting their dielectric loss properties. The PMC absorber exhibited excellent electromagnetic wave absorption (EMA) performance, with a maximum effective absorption bandwidth (EABmax) of 6.76 GHz, and a minimum reflection loss (Rlmin) of-64 dB. In addition, an unmanned aerial vehicle (UAV) was used as a model to simulate an actual radar cross-section (RCS). The results show that the RCS of the UAV was halved after coating with PMC, indicating that the fabricated absorber has good practical application potential. This study provides a common strategy for constructing absorbers with ingenious structures, which is significant for the preparation, development, and application of HCM-based absorbers.