Exceptional Electromagnetic Wave Absorption in High-Entropy Carbides Enabled by Lattice Distortion Engineering

en This link goes to a English section zh This link goes to a Chinese section The growing concern over human health issues, driven by increasingly severe electromagnetic pollution from 5G communication, has made the urgent development of high-performance electromagnetic wave (EMW) absorbing materials. Although carbide-based materials are promising because of their conductive and polarization losses, existing single-component materials fall short of future requirements. We report a lattice distortion engineering strategy to design and synthesize a stable high-entropy carbide (Ta 0.2 Nb 0.2 Ti 0.2 Zr 0.2 Cr 0.2 )C. The lowest reflection loss reaches −62.40 dB, and it exhibits an effective absorption bandwidth (EAB) of 6.39 GHz, a fourfold enhancement compared to that of the single component material TaC. Results indicate that severe lattice distortion in the high-entropy composition induces the formation of high-density defects, and the presence of metal vacancies significantly enhances the high-entropy carbides conduction loss and dipole polarization. Concurrently, the abundant grain boundaries and hyper-dense distorted lattices provide significant interfacial polarization and relaxation polarization, effectively broadening the electromagnetic absorption bandwidth. Electron holography analysis confirmed that a substantial accumulation of positive and negative charges at nano-interfaces leads to an anomalous dielectric polarization loss. This study contributes an effective pathway for designing potent single-phase electromagnetic wave absorption materials and provides a paradigm for improving other properties of high-entropy carbides via the lattice distortion strategy. 摘要 en This link goes to a English section zh This link goes to a Chinese section 随着5G通信引发的电磁污染日益严重,人们对健康问题的关注日益增加,这促使高性能电磁波吸收材料的开发成为当务之急。虽然碳化物基材料因其导电性和极化损耗而具有潜力,但现有的单组分材料仍无法满足未来需求。我们提出了一种晶格畸变工程策略,用于设计并合成稳定的高熵碳化物(Ta 0.2 Nb 0.2 Ti 0.2 Zr 0.2 Cr 0.2 )C。其有效吸收带宽(EAB)达到6.39 GHz,较单组分材料TaC提升了四倍,并且反射损耗最低可达−62.40 dB。结果表明,高熵成分中的严重晶格畸变会诱导形成高密度缺陷,而金属空位的存在显著增强了高熵碳化物的导电损耗和偶极极化。同时,丰富的晶界和超致密畸变晶格提供了显著的界面极化和弛豫极化效应,有效拓宽了电磁吸收带宽。电子全息分析证实,纳米界面处正负电荷的大量聚集导致了异常的介电极化损耗。本研究为设计高效单相电磁波吸收材料提供了有效途径,并通过晶格畸变策略为提升高熵碳化物的其它性能提供了范式。