Microtubule-based hierarchical porous carbon for lightweight and strong wideband microwave absorption

Abstract

A lightweight and high-performance electromagnetic wave absorbing material, microtubule-based hierarchical porous carbon (MHPC), was realized by a feasible pretreatment and thermal annealing process. The unique architecture not only effectively reduced the carbon density, but also significantly contributed to impedance matching, inner multi-scattering, conductive loss, and dielectric polarization, thereby achieving extraordinary microwave absorption performance. An exceptionally strong reflection loss (RL) of −63.5 dB at 14.5 GHz and a wide effective absorption bandwidth up to 7.3 GHz covering the whole Ku band and half X band were revealed. Simultaneously, a superior specific reflection loss was attained under a low absorber loading (15 wt%) and an ultralow density (0.170 g cm⁻³). The fundamental microwave absorbing mechanism of typical MHPC was discussed. This study provides an important strategy toward the mass production of a sustainable, lightweight, and strong broadband microwave absorption material.