Bridging microscopic phase and defect manipulation with macroscopic core-sheath-shell structure for polarization-dominated electromagnetic wave absorption

Abstract

Manipulating phases and defects brings boundless vitality to the design of electromagnetic wave (EMW) absorption (EMA) materials. However, current manipulations often prioritize the improvement in the overall EMA performance without distinguishing the effects of individual polarizations. Therefore, the design of EMA materials is result-oriented and limited by reliance on semi-empirical rules. Herein, we synthesized carbon cloth (CC)@MoS2@carbon nanotubes (CNTs) (CMSC) by self-assembly of MoS2 on CC, followed by in-situ growth of CNTs through high-temperature annealing. This synthesis process not only created a hierarchical core-sheath-shell structure consisting of an MoS2 intermediate sheath and a CNT outer shell but also introduced tunable vacancy defects and phases (2 H and 1 T). Density Functional Theory calculations revealed an enhanced carrier influx from the CNTs into the 2 H/1 T MoS2 due to the substantial difference in work function between the 1 T and 2 H phases, which promoted charge redistribution and subsequent polarization at defect sites and interfaces in CMSC. Therefore, defect-induced and interfacial polarizations dominated the EMW-attenuation mechanisms for CMSC, distinguishing it from CC@MoO2@CNTs, where conduction loss predominated. Owing to these enhanced polarizations and core-sheath-shell structure, CMSC exhibited a minimum reflection loss of −43.9 dB at 2.1 mm, even with a filler ratio of 3 wt%. This study highlights the potential for designing and tailoring polarization-dominated EMA materials through the manipulation of defects and phases.