Ni@C composites derived from Ni-based metal organic frameworks with a lightweight, ultrathin, broadband and highly efficient microwave absorbing properties

Abstract

The Ni@C composites were successfully synthesized by thermal decomposition of a Ni-based metal organic framework (Ni-MOF). By varying the pyrolysis temperature, Ni@C composites with different morphology and microstructure can be easily synthesized. Benefiting from the synergistic effect between the Ni core and carbon shell, the composite possess good impedance matching and excellent microwave absorption performance. Interestingly, the strongest absorption of the Ni@C composite reaches −55.7 dB corresponding to 6.0 GHz absorption bandwidth (<−10 dB) at a thickness of 1.85 mm. The results demonstrate that Ni@C composites may be promising microwave absorption materials because of their strong absorption, being lightweight, thin thickness and large absorption bandwidth.

Effect of Surface Structure and Composition on the Electromagnetic Properties of Ti3C2Tx MXenes for Highly Efficient Electromagnetic Wave Absorption

“…Concomitantly, the (002) planes tend to be broader and obviously shift to lower angles after HF treatment, indicating the increase of d -spacing in MXenes. In Figure b, there are two evident peaks at about 1342 and 1585 cm –1 , which can be assigned to the D band and G band, respectively . The intensity ratio I D / I G was evaluated for the amounts of defects in the graphitic carbon materials. − With an increase in the HF etching time, I D / I G increases from 0.98 to 1.05 because of the significant increase of defects and functional groups in the Ti 3 C 2 T x MXenes.…”

High-Performance Electromagnetic Wave Absorbers Based on Two Kinds of Nickel-Based MOF-Derived Ni@C Microspheres

“…In Figure 2a,c, the XPS spectra of Ni@C-ZIF and Ni@C-BTC both showed the distinct signal peaks; three typical peaks at 284.8, 532.1, and 855.5 eV were observed, which corresponded to the spectra of C 1s, O 1s, and Ni 2p, respectively, suggesting that the C, Ni, and O elements existed in both composites. The existence of oxygen can be attributed to the surface weak oxidation of Ni nanoparticles in the air 39,40 and to the MOF structure that is not completely pyrolyzed. In Figure 2a, we can elemental mapping was performed to quantify a uniform distribution of carbon, oxygen, nitrogen, and nickel components.…”

Enhanced Microwave Absorption Bandwidth in Graphene-Encapsulated Iron Nanoparticles with Core–Shell Structure

“…With the rapid development of electronic and wireless technologies, electromagnetic interference (EMI) and pollution are becoming serious issues worldwide, affecting more and more electronic integrated devices and the living environment [1,2]. In order to solve these ever-growing serious environment issues, absorbing materials are required to present a number of characteristics (e.g., wide absorption bandwidths, intense absorption, lightweight, and low thickness), the so-called "thin, light, wide, and strong" requirements.…”