Constructing BaTiO₃/TiO₂@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties

BaTiO₃/TiO₂@polypyrrole (PPy) composites with hollow multishelled structure (HoMS) were constructed to enhance the electromagnetic wave absorbing properties of BaTiO₃-based absorbing material. BaTiO₃/TiO₂ HoMSs were prepared by hydrothermal crystallization using TiO₂ HoMSs as template. Then, FeCl₃ was introduced to initiate the oxidative polymerization of pyrrole monomer, forming BaTiO₃/TiO₂@PPy HoMSs successfully. The electromagnetic wave absorbing properties of BaTiO₃/TiO₂ HoMSs and BaTiO₃/TiO₂@PPy HoMSs with different shell number were investigated using a vector network analyzer. The results indicate that BaTiO₃/TiO₂@PPy HoMSs exhibit improved microwave absorption compared with BaTiO₃/TiO₂ HoMSs. In particular, tripled-shelled BaTiO₃/TiO₂@PPy HoMS has the most excellent absorbing performance. The best reflection loss can reach up to −21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm, and the qualified absorption bandwidth of tripled-shelled BaTiO₃/TiO₂@PPy HoMS is up to 4.2 GHz. This work paves a new way for the development of high-performance composite microwave absorbing materials.