Rational construction of mushroom-like Ni@N-doped carbon tubes composites with enhanced electromagnetic wave absorption

It is confirmed that electromagnetic wave absorption (EMA) materials with a metal-carbon dual-phase structure has exposed great potential for achieving tunable, strong, and wide EMA. Herein, the mushroom-like Ni@N-doped carbon tubes (NNCTs) are prepared by nickel-catalyzed growth of carbon tubes, realizing carbon encapsulated metal particles. One end of the carbon tube grows and connects to form a bundle of mushroom-like structures, and the other end of the carbon tube is filled with nickel as the mushroom head. The structure control of NNCTs can be achieved by adjusting the amount of catalyst Ni. Appropriate amount of nickel can control the formation of mushroom-like structure. The results show that the structure has a great influence on the EMA performance. Particularly, NNCT-0.5 provides a minimum reflection loss of -60.47 dB with a thickness of 4.0 mm, and the widest effective absorption bandwidth for RL< -10 dB of NNCT-1.5 at a thickness of 2.00 mm was 7.53 GHz (10.47–18.00 GHz). The immobilization of carbon in melamine was achieved by catalytic generation of carbon tubes with metal ions Ni. Metal-carbon biphasic composites introduce dielectric and magnetic losses. The presence of multiple interfaces and voids in the mushroom structure allows tuning the dielectric parameters and optimizing the impedance matching. This work provides an effective strategy for the fabrication of dielectric and magnetic composites with special structures, which has great potential in attenuating electromagnetic wave energy.