Microwave absorption performance of porous carbon particles modified by nickel with different morphologies

Abstract

• Porous carbon particles (PCPs) derived from flour were successfully prepared. • The nickels with different morphologies were successfully deposited on PCPs. • Only PCPs deposited chain-shaped nickels obtained better performance. • PCPs with chain-shaped nickels showed the best impedance matching. • PCPs with chain-shaped nickels exhibited the strongest loss ability. In this work, porous carbon particles were prepared from wheat flour by pyrolysis and activation. Through the subsequent coprecipitation and electroless plating, the surface and pores of carbon particles were modified by nickel-rich particles with different morphologies. Several loss mechanisms, including dielectric loss, magnetic loss, multiple reflection and scattering loss, were used to assess the attenuation ability to incident electromagnetic waves of these composite particles. The result shows that the chain-shaped morphology of nickel can provide the highest dielectric loss. Under the filler loading of 20 wt.%, the minimum reflection loss (RL min ) reached -38.42 dB at 13.2 GHz, and the maximum effective absorption bandwidth (EAB max ) was 5.2 GHz with a matching thickness of 2 mm. The excellent performance of the composite particles is attributed to the synergistic effect of outstanding impedance matching and superior electromagnetic loss ability caused by the chain structure. The result shows that the morphology of modifiers in carbon-based composites is important to improve microwave absorption performance, and this work provides inspiration for the design of high-performance porous carbon-based composites.