Nanoscale polygonal carbon: a unique low-loading filler for effective microwave absorption

In this work, silica template was utilized into the phenol resin to fabricate a novel nanoscale polygonal carbon (NPC) toward effective microwave absorption fillers. The as-prepared NPC with polygonal features presents substantial improvement in the complex permittivity of the wax-based composites. The porous structure coupled with electrical conduction and polygonal characteristic enables the NPC to form an effective electrical loss network via the formation of unique 3D pathways. Therefore, the composite embedded with NPC delivers strong microwave absorption up to -38 dB at a low filler loading of 3 wt%, with a much broadened effective absorption bandwidth in the range of 7-13 GHz. In addition, the fundamental mechanisms of the complex permittivity and broadened effective absorption bandwidth have been intensively discussed, indicating more advantages in comparison with some graphene- or carbon nanotube-based fillers. The results suggest that the exclusive performance induced by the NPC promises great potential in the achievement of advanced microwave absorption composites with low-loading fillers.