3D skeletal porous nanocage of ternary metallic oxide with excellent electromagnetic wave absorption

With the development of radio technologies, great efforts have been made to manufacture high-performance electromagnetic wave (EMW) absorbers for electronic information security, anti-reconnaissance stealth and human health protection. Reaching both excellent impedance matching and electromagnetic (EM) energy dissipation at the same time is still a challenge for EMW absorption materials. In this study, a 3D skeletal porous nanocage structure made from Co-Fe-Ni ternary metal oxide (CFN-TMO) was designed to simultaneously improve the impedance matching and guarantee sufficient EM energy dissipation of the EMW absorber. The integrity of the 3D skeletal nanocage structure and pore size on the cage wall can be tailored by the calcination temperature to optimize its EMW absorption capability. With a suitable pore size and complete skeleton structure, the best performance of the nanocage reaches a high reflection loss (RL) of -67.2 dB and an ultra-wide effective absorption bandwidth (EAB) of 8.2 GHz. The outstanding EMW absorption performance is mainly attributed to the nanocage structure, which can optimize the impedance matching and trigger multiple reflections of the EMWs. The skeleton constructed with the Co-Fe-Ni ternary metal oxide can improve the EMW dissipation by introducing a large number of interfaces, lattice defects and oxygen vacancies. This work reveals a nanostructure design route for optimizing the impedance matching, which can greatly increase the EMW absorption and provide important guidelines for the design and fabrication of lightweight and high-performance EMW absorption nanomaterials.