ZIF-67 derived CoNi@carbon/RGO composites with abundant heterogeneous interfaces for electromagnetic wave absorption

The controllable structure design and composition regulation play a key role in the development of electromagnetic wave (EMW) absorbing material. Herein, CoNi@carbon/RGO absorbing materials were successfully prepared by direct pyrolysis of ZIF-67/Ni(OH)2/GO precursor. The CoNi@carbon/RGO-15 sample achieves an RLmin value of −46.14 dB and an effective absorption bandwidth (EAB) of 1.15 GHz (thickness 4.1 mm) at a low frequency with a filling amount of only 10 wt%. When the thickness is 1.5 mm, the RLmin reaches −41.09 dB and the EAB reaches 5.41 GHz, covering most of the Ku bands. After the pyrolysis, the carbon layer, Co and Ni nanoparticles, and RGO nanosheets form a three-dimensional porous structure, which builds up abundant heterogeneous interfaces and conductive networks. These factors can enhance impedance matching, dielectric, and magnetic loss. This indicates that CoNi@carbon/RGO is the potential lightweight EMW absorbing material with high performance.