N-doped porous carbon nanoplates embedded with CoS2 vertically anchored on carbon cloths for flexible and ultrahigh microwave absorption

Abstract

Metal-organic-frameworks (MOF) derived carbon materials are usually utilized as microwave absorbers, however, the practical application of the powders in flexible devices is restricted. Herein, a facile strategy is developed for in-situ vertically grown of Co-MOF precursor on conductive carbon cloths, followed by the carbonization and sulphidation process. The synthesized flexible composites, in which intertwined carbon cloths act as the skeleton, hierarchical N-doped porous carbon nanoplates anchor on the substrate and CoS2 particles are encapsulated by graphitic carbon, exhibit ultrahigh microwave absorption because of the conductive network, hierarchical porous architecture, enhanced dipolar/interfacial polarization, multi-scattering and promoted impedance matching. The thickness of graphitic carbon can be tuned from 12 layers to 25 layers by adjusting the carbonization temperature and the flexible composites annealed at 700 °C outperform others in terms of microwave absorption performance. Typically, the maximum reflection loss (RL) is up to −59.6 dB at 2.8 mm and the effective bandwidth (RL < −10 dB) reaches as wide as 9.2 GHz with a thickness of 2.5 mm. Consequently, this strategy offers a novel thought for large-scale construction of flexible carbon composites with effective microwave response and the resulted composites possess a promising potential in the practical application of portable microwave absorption electronic devices.