Synthesis of Nonspherical Hollow Architecture with Magnetic Fe Core and Ni Decorated Tadpole-Like Shell As Ultrabroad Bandwidth Microwave Absorbers

The advancement of electromagnetic (EM) protection technology promotes the urgent demand for the structural design of electromagnetic functional materials. Here, tadpole-like Fe@SiO @C-Ni (FSCN) composites with magnetic core-shell and nonspherical hollow architectures through multiple hydrolysis-polymerization reactions are reported. The Fe core and well-distributed Ni nanoparticles greatly promote the magnetic properties of FSCN and construct a multiscale magnetic coupling network. Meanwhile, the multishell composites consisting of carbon shell with Ni decorated possess an abundance of heterogeneous interfaces, generating effective interfacial polarization and relaxation. The hollow feature and the coordination of magnetic and dielectric capacities offer an optimized impedance balance, providing a fundament for the microwaves propagating into the absorber. Owing to the attractive effects resulted from the deliberate tadpole-like structure design, the FSCN composites ensure an effective EM energy conversion at the high-frequency region, which obtain the strongest reflection loss value of -45.2 dB and the extremely broad effective absorption bandwidth of 13.1 GHz. This work provides an important solution for magnetic-dielectric nanostructure design for microwave absorption and energy conversion materials.