Balancing between Polarization and Conduction Loss toward Strong Electromagnetic Wave Absorption of Hard Carbon Particles with Morphology Heterogeneity

The heterostructure and hierarchical morphology of carbonaceous absorbents play an important role in the construction of high-performance electromagnetic wave absorbing materials. Herein, novel micron-scale hard carbon particles with morphology heterogeneity were developed as lightweight superior electromagnetic wave absorbents via a facile and ecofriendly process. The as-prepared hard carbon particle composed of pseudographite and a highly disordered region shows a unique heterostructure. Concurrently, constructing a multilevel geometric shape and size can cause a decrease of the percolation threshold and an excellent balance between polarization and conduction loss, which enhances the electromagnetic wave absorption significantly. The composites (thickness d = 2.36 mm) filled with morphology-heterogeneity hard carbon particles (15 wt %) achieve an excellent electromagnetic wave absorption with a minimum reflection loss of -78.0 dB at 10.2 GHz and effective absorption bandwidth (<-10 dB) of 3.1 GHz (8.8-11.9 GHz). Compared to the traditional carbonaceous absorbents with complex microstructures and/or multiple chemical components, this work presents a feasible idea for the development of an efficient carbonaceous absorbent to realize practical applications.