Flexible Film Constructed by Asymmetrically‐Coordinated La₁N₄Cl₁ Moieties on Interconnected Nitrogen‐Doped Graphene Nanocages for High‐Efficiency Electromagnetic Wave Absorption

Abstract

The microenvironments of metal single‐atoms (SAs) have important effects on their physicochemical properties. However, the understanding of the relationship between the coordination configuration of SAs and their properties is insufficient. Here, a sacrificing template strategy is developed to anchor La‐SAs on interconnected graphene nanocages (La‐N‐Cl/GNC), where La‐SAs are located above the graphene plane and one La atom coordinated with four N atoms in the graphene plane and with one Cl atom along the axial direction. Theoretical calculations demonstrated that asymmetrically La‐SAs are more conducive to breaking local charge symmetry. Consequently, additional electrical dipoles along the axial direction are generated, leading to unprecedented dipolar polarization loss and strong electromagnetic wave absorption properties. Moreover, the film constructed by asymmetrically‐coordinated La‐N‐Cl/GNC with a mass density of 0.084 g cm−3 exhibits superior flexibility, excellent mechanical strength, and moderate thermal insulation properties, guaranteeing its practical applications in harsh environments. These findings not only shed light on the relationships between asymmetrically coordinated SAs and their dielectric properties at the atomic level but also provide an efficient method for preparing multifunctional films.

Activating Excellent Electromagnetic Wave Absorption of Micromorphology-Optimized Cu/C Nanocomposite Fibers via a Metal–Organic Framework Template-Assisted Strategy

“…As reported, the semicircular observed in the Cole−Cole plot originates from the polarization process, while the elongated tail line denotes the conductive loss. 65,66 It is evident that all samples exhibit a tail, suggesting the significance of the position of conductive loss. Meanwhile, the curves are distorted to form multiple semicircles, which correspond to the polarization relaxation peaks appeared in the ε″ curves (Figure 5b).…”

Embedded Ni/NiO Heterostructure in MoO3–x Nanorods toward Reinforced Interfacial Polarization for Electromagnetic Wave Absorption

“…Hence, conduction loss and polarization loss are calculated by ε c ″ = σ/ε 0 ω and ε p ″ = ε′′ – ε c ″ (eqs S4–S6). , The conductivity of the samples is measured with values of 0.011, 0.268, and 0.318 S/cm for NiO/MoO 3– x , NiO/Ni/MoO 3– x , and Ni/MoO 3– x composites, respectively. As shown in Figure g, except for NiO/MoO 3– x , the conduction loss exhibits an apparent gradual downward trend with increasing frequency, which demonstrates that conduction loss mainly contributes to the EMW absorption in the low frequency range.…”

“…The rapid development of electromagnetic communication technology unavoidably brings electromagnetic radiation in the surrounding environment, which not only produces negative impacts on human health but also interferes with the normal operation of precise instruments. − Electromagnetic wave (EMW) absorption materials, as energy conversion intermediates, can effectively dissipate the incident electromagnetic energy into heat energy via the internal diverse dissipation mechanisms. − However, the disadvantages of narrow absorption bandwidth and complex preparation processes of most electromagnetic functional materials restrict further practical application. Therefore, the exploration of highly efficient EMW absorption materials with a wide frequency response range is highly promising to address the above challenges.…”