Advanced Science
·
2023
·Vol. 10
·期 10
·2206877
·
IF 15.1
Lu Chen,Youbing Li,Biao Zhao,Shanshan Liu,Huibin Zhang,Ke Chen,Mian Li,Shiyu Du,Faxian Xiu,Renchao Che,Zhifang Chai,Qing Huang
Electromagnetic (EM) wave pollution is harmful to human health and environment, thus it is absolutely important to develop new electromagnetic wave absorbing materials. MAX phases have been attracted more attention as a potential candidate for electromagnetic wave absorbing materials due to their high conductivity and nanolaminated structure. Herein, two new magnetic MAX phases with multiprincipal elements ((Ti 1/3 Nb 1/3 Ta 1/3 ) 2 FeC and (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 Zr 0.2 ) 2 FeC) in which Fe atoms replace Al atoms in the A sites are successfully synthesized by an isomorphous replacement reaction of multiprincipal (Ti 1/3 Nb 1/3 Ta 1/3 ) 2 AlC and (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 Zr 0.2 ) 2 AlC MAX phases with Lewis acid salt (FeCl 2 ). (Ti 1/3 Nb 1/3 Ta 1/3 ) 2 FeC and (Ti 0.2 V 0.2 Nb 0.2 Ta 0.2 Zr 0.2 ) 2 FeC exhibit ferromagnetic behavior, and the Curie temperature ( T c ) are 302 and 235 K, respectively. The dual electromagnetic absorption mechanisms that include dielectric and magnetic loss, which is realized in these multiprincipal MAX phases. The minimum reflection loss (RL) of (Ti 1/3 Nb 1/3 Ta 1/3 ) 2 FeC is −44.4 dB at 6.56 GHz with 3 mm thickness, and the effective bandwidth is 2.48 GHz. Additionally, the electromagnetic wave absorption properties of the magnetic MAX phases indicate that magnetic loss also plays an important role besides dielectric loss. This work shows a promising composition-design strategy to develop MAX phases with good EM wave absorption performance via simultaneously regulating dielectric and magnetic loss together.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Linjing Qiao,Jianqiang Bi,Yao Yang,Guandong Liang,Shaoyin Wang,Hongyi Wang
Nowadays, the increasingly severe electromagnetic (EM) wave pollution requires high-performance EM wave absorbing materials. Multi-principal-element materials are acknowledged as promising for broadening the applications owing to their tunable chemistries and structures in many fields, including as EM wave absorbers. Herein, we prepared a high-entropy MXene , (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x . Furthermore, multi-principal-element (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x /FeCoNi and (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x /FeCoNiCu composites were synthesized via an in-situ hydrothermal process by combining high-entropy MXene with medium-entropy magnetic alloys . In contrast with the relatively narrow effective absorption bandwidth (EAB) of (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x MXene (2.56 GHz), (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x /FeCoNi composite with 50 wt% MXene can attain an optimum EAB of 4.88 GHz with the matching thickness of only 1.73 mm. As for (Mo 0.25 Cr 0.25 Ti 0.25 V 0.25 ) 3 C 2 T x /FeCoNiCu composites, both the absorption efficiency and absorption bandwidth are significantly enhanced. The combination of multi-principal-component strategy and composite construction endows the composites with synergistic dielectric and magnetic losses, optimized impedance matching as well as enhanced attenuation ability, thus improving EM wave absorption performances. In addition, radar cross section (RCS) simulation confirms that the prepared composites have broad application prospects as radar stealth materials.
研究领域:
材料科学
·
电磁工程
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
Materials Today
·
2023
·
IF 24.2
Yiyuan Yang,Zhe Jia,Xinyue Zhang,Yujing Liu,Qianqian Wang,Yongjie Li,Liliang Shao,Siyi Di,Juan Kuang,Ligang Sun,Lai-Chang Zhang,Jamie J. Kruzic,Yang Lu,Jian Lu,Baolong Shen
The superior electrocatalytic activity of multi-principal element alloys (MPEAs) is typically attributed to synergistic effects of their multi components in random solid solutions. Strategies to control the functional atoms with a chemically ordered atomic distribution and the specific atomic configuration in the MPEAs remain a challenging research topic. Here, we have discovered non-random, chemical short-range order (CSRO) in a Fe 10 Co 5 Ni 10 Cu 15 Al 60 MPEA induced by magnetic characteristics of elements, leading to ultralow overpotential for dual-electrode water splitting in alkaline condition. Atomic-resolution imaging and elemental mapping assisted by statistical analysis and density functional theory (DFT) simulations revealed that CSRO in the MPEA originated from the nearest-neighbor preference of M-Cu (M = Fe, Co, Ni, and Al) pairs and repulsion of same-element pairs (Fe-Fe, Co-Co, Ni-Ni, Cu-Cu, and Al-Al). Such preferential atomic pairs facilitated H 2 O/H* adsorption/desorption during the hydrogen evolution reaction and reduced the energy barrier for the rate-determining step of the oxygen evolution reaction , thereby promoting excellent overall water splitting performance. The achieved current density (130 mA cm −2 ) of the low-cost MPEA was ∼4 times higher than that of the Pt/C||RuO 2 dual-electrode system (32 mA cm −2 ) at a cell voltage of 2.0 V. The concept of CSRO in MPEAs offers new insights into their multi-functional applications, potentially spurring the development of numerous high-performance MPEA-based devices for the energy and environmental sectors.
研究领域:
材料科学
·
电化学
·
催化
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）