A novel MOF-drived self-decomposition strategy for CoO@N/C-Co/ Ni-NiCo2O4 multi-heterostructure composite as high-performance electromagnetic wave absorbing materials

The construction of multiple heterointerfaces by materials with more complementary or enhanced properties are advanced strategic direction to solve the problem of electromagnetic wave absorption. In this work, the novel Tremella-like NiCo2O4 (NCO) combining with dodecahedral Co-MOF (ZIF67) heterointerfaces were constructed as the first time. Significantly, the heterointerfaces reconstruction and EMWA performance of NCO@ZIF67 were investigated in different pyrolysis temperature. The results reveal that the NCO@ZIF67 transformed into CoO@N/C, CoO@N/C-Co/Ni-NCO, Co/Ni@N/C multiple heterointerfaces composites by self-decomposition and phase transition at different temperature. CoO@N/C shows RL of -77.46 dB with EAB of 3.15 GHz; final composites Co/Ni@N/C shows RL of -61.73 dB with EAB of 2.07 GHz. Especially, CoO@N/C-Co/Ni-NCO multiple heterointerfaces composites not only show excellent RL of -52.45 dB at 14.77 GHz, but also ultrawide EAB of 5.3 GHz, matching thickness of only 1.66 mm, which exhibited the best EMWA performance among three variants, attributing to the synergistic effect of enhanced conductivity loss, strong dipole polarization and multi-interfaces polarization, and the best impedance matching characteristics. This research will provide a novel and meaningful strategic thinking for the construction of multiple heterointerfaces, and maybe enter the ranks of advanced electromagnetic wave absorbing materials.