Tailoring Ni3ZnC0.7/graphite heterostructure in N-rich laminated porous carbon nanosheets for highly efficient microwave absorption

Bimetallic transition carbide nanoparticles (Ni3ZnC0.7) encapsulated with graphitic shells were successfully embedded into N-rich laminated porous carbon nanosheets (NC–ZnNi1.5) by one-step pyrolysis of bimetallic organic frameworks. It was found that C atoms penetrated octahedral interstitial spaces of the Ni lattice to form Ni3ZnC0.7. The charge states and distribution of metal atoms were influenced by the interstitial C atoms, which promoted polarization relaxation and facilitated dielectric loss. Simultaneously, the volatilization of Zn influenced recrystallization and rearrangement of the crystalline domains, facilitated graphitization and established a 3D conductive network to optimize the conductive loss. Besides, multi-level heterogeneous interface and nitrogen doping also further optimized the impedance matching. Benefiting from these advantages, the minimum reflection loss of NC-ZnNi1.5 was −69.1 dB at 12.7 GHz, and the effective absorption bandwidth was 6.5 GHz. The mechanism of bimetallic carbide's dielectric loss was explained in detail, providing a new pathway for the development of multi-component carbon-based microwave absorbers in the future.