Compressible and flexible PPy@MoS2/C microwave absorption foam with strong dielectric polarization from 2D semiconductor intermediate sandwich structure.

Abstract

Structural engineering represents a major trend in the field of two-dimensional (2D) materials regarding microscopic interfacial electric/dielectric properties and macroscopic device strategies. 2D molybdenum disulfide (MoS2) with semiconductive features and lamellar architecture has been widely applied in the microwave absorption (MA) field. However, due to its limitations of weak dielectric loss capacity and poor intrinsic mechanical property, MoS2-based MA devices are a considerable design challenge for practical applications with the peculiarities of light weight, high absorption performance, flexibility, and compressibility. Herein, 2D MoS2 was riveted on carbonized melamine foam (CMF) templated from a commercial foam skeleton, which was cladded with the conductive polymer polypyrrole (PPy). The as-prepared PPy@MoS2/CMF was integrated to simultaneously achieve an excellent MA performance including a maximum reflection loss (RL) value of -45.40 dB and a wide absorption bandwidth of 3.8 GHz, together with mechanical practicability including a high compression ratio of over 45.6% in volume and a bending angle of over 43.2°. This excellent MA performance is attributed to the synergetic effect from its sandwiched multi-layered skeleton, consisting of a conductive/semiconductive/conductive ternary conductive network, and multiple polarizations from the 2D MoS2 interlayer. Our strategy sheds novel insight into the construction of advanced carbon-supported composites and 2D materials for use in devices, which can be further extended to energy storage and conversion applications.