Vertically stacked heterostructures of MXene/rGO films with enhanced gradient impedance for high-performance microwave absorption

Owing to high specific surface area and electrical conductivity, 2D materials are widely used for microwave absorption to address the problems of electromagnetic wave pollution, which induced by the advancement of wearable electronic devices and 5G wireless communication. However, the major challenges arise from the unsatisfied dielectric loss capacity that seriously limits the application of 2D-based microwave absorber. Herein, a vertical heterostructure architecture was exploited to synthesize MXene/rGO films, which deliver different impedance gradients. In particular, the MrG film with 80 wt% rGO content exhibit excellent microwave absorption with a minimum reflection loss value of −44.3 dB at 7.06 GHz (＞99.99% of the electromagnetic wave is absorbed) and an effective absorption bandwidth of 4.84 GHz at a thickness of 1.5 mm. The enhanced dielectric loss capacity is attributed to vertically stacked heterostructures, providing new electron transport and leap channels along the vertical direction of the films. Moreover, visualized power loss density simulations are first used to investigate the evolution of the loss densities, further confirming the synergistic interaction between MXene and rGO can substantially increase microwave absorption. This finding provides an alternative approach for the developing efficient, customizable, simple, and low-cost 2D material-based absorbers through controlling formation of vertical heterostructures.