Size-controllable porous flower-like NiCo2O4 fabricated via sodium tartrate assisted hydrothermal synthesis for lightweight electromagnetic absorber.

Although the performance of NiCo2O4-based absorbers with multiple components has made great progress, the property of pure NiCo2O4 is still far from the requirements of high-performance electromagnetic wave absorbers. It is recognized that morphology control is an effective strategy to improve electromagnetic absorbing capacity of absorbers. Herein, this work reported the fabrication of porous flower-like pure NiCo2O4 via simple hydrothermal reaction with the assistant of sodium tartarate in where tartaric acid served as a structure-directing agent. It was demonstrated that size distribution and electromagnetic absorbing capacity of the obtained NiCo2O4 could be modulated easily by controlling addition of sodium tartrate. It was verified that dipole polarization originated from lattice defect and oxygen vacancy as well as interfacial polarization ascribing to adjacent and interconnected flakes are responsible for the excellent electromagnetic absorbing performance. The obtained porous flower-like NiCo2O4 exhibited broad absorption bandwidth at thin thickness as well as proper dissipation ability. This work offers a new strategy to fabricate size-controllable porous flower-like NiCo2O4 electromagnetic absorber. It is believed the obtained NiCo2O4 will be a promising candidate as a lightweight electromagnetic absorbing material.