Biomass-derived heterogeneous RGO/Ni/C composite with hollow structure for high-efficiency electromagnetic wave absorption

Comprehensive consideration of appropriate composite technique to maintain the original structure of the absorbent with unique morphology is the critical strategy to take full advantages of its performance advantages. In this work, the cotton fiber derived heterogeneous RGO/Ni/C composite with hollow structure was successfully synthesized through in-situ pyrolysis process. Benefited from the pressure casting-assisted method, the original microstructure of the RGO/Ni/C composite was protected and maintained perfectly in the matrix during the composite process. Hence, the hollow structure extended the propagation path of electromagnetic wave (EMW) contributing to multiple reflection and scattering. The carbon fibers constructed a continuous 3D network enhancing the conduction loss and abundant heterogeneous interface endowed the hybrid material with sufficient interfacial polarization. Attributed to fully functioning of structural advantages and synergistic effect of loss mechanisms, the maximum reflection loss (RL) reached to −39.3 dB and the effective absorption bandwidth (EAB) was 4.6 GHz at 2.0 mm with a fairly low filler content of 8.4 wt% which were superior to those of 40 wt% prepared by mixing-grinding method. This research would explore a new attempt direction to help the EMW absorbing materials fully demonstrate its EMW absorption performance by adequately consider the original structure preservation and rational composite technique.