Radially Channel Engineering for N/O Co-doped Carbon Sphere towards High-performance and Multiband Microwave Absorption

Although spherical carbon exhibits excellent dielectric loss capability, its practical application is hindered by impedance mismatch and high filler content, which are the main reasons for unsatisfactory performance. To overcome these limitations, N/O Co-doped carbon sphere with radially porous configuration (RPCS) was fabricated via a self-templated route. The in situ doped heteroatoms can provide dipole polarization relaxation, while the radial pores are beneficial for lightweight, low dosage and moderate impedance. Through investigation, it can be concluded that varying the preparation temperature can effectively adjust the ultimate absorption properties. As the optimal sample, the RPCS-800 delivers the absorption intensity exceeding -40 dB in multiple wavebands. In particular, the strongest absorption of -56.5 dB is realized at a thin thickness of 1.85 mm, accompanied with an effective absorption bandwidth of 5.5 GHz. This outstanding electromagnetic protection characteristic is further validated through the CST simulation, with a maximum RCS reduction of 25.9 dB m². The obtained RPCS material shows obvious merits compared to the previously reported carbon-sphere based absorbers. Therefore, this study may provide new inspiration for the development of lightweight and multiband spherical carbon absorbing materials.