Lightweight polymer-based nanostructured aerogels are crucial for electromagnetic interference (EMI) shielding to protect electronic devices and humans from electromagnetic radiation. The construction of three-dimensional (3D) conductive networks is crucial to realize the excellent electromagnetic shielding performance of polymer-based aerogels. However, it is difficult to realize the interconnection of different conductive fillers in the polymer matrix, which limits the further improvement of their performance. Herein, 3D ordered hierarchical porous Fe3O4-decorated carbon nanotube (Fe3O4@CNT)/MXene/cross-linked aramid nanofiber (c-ANF)/polyimide (PI) aerogels were prepared via a unidirectional freezing strategy. Benefiting from the magnetic loss effect of Fe3O4 magnetic nanoparticles, the conductive and dielectric loss effects of CNTs, and the multiple reflections induced by the 3D ordered hierarchical porous structure, the Fe3O4@CNTs/MXene/c-ANFs/PI (FMCP) aerogels with the same contents of 8 wt % of Fe3O4@CNTs and MXene exhibit a high absolute EMI shielding effectiveness (SE) of up to 67.42 dB and a microwave reflection (SE R ) of 0.60 dB. More importantly, the phase transition of a small amount of MXene to TiO2 optimizes the impedance matching and transmission and then improves the microwave absorption. The FMCP aerogel has an outstanding normalized surface specific SE (SSE/t) which is up to 62,654 dB cm2·g–1. Meantime, the FMCP aerogels also show super-elasticity and could maintain 91.72% of the maximum stress after 1000 cycles of compression release under a fixed deformation of 60%.
A unique and highly efficient means to ameliorate the thermal conductivities (TCs) of polymers towards the polymer-based thermal management materials is by introducing high-thermal conductivity nanofillers to prepare polymer composites. However, in order to obtain high TC, the large content of a single filler often brings serious dispersibility problems which greatly affect the improvement of the TC. Meantime, in a polymeric matrix, it is difficult for a single nanofiller itself to form the heat conduction path. Herein, in order to overcome the above-mentioned problems, we introduced highly thermal conductive nanofillers like two-dimensional (2D) functionalized boron nitride nanoflakes (f-BNNS), MXene (Ti 3 C 2 T x ), and one-dimensional (1D) silver nanowires (AgNWs) into the polybenzimidazole (PBI) matrix together. It is found that the introduction of high-aspect-ratio AgNWs could not only improve the dispersion of nanofillers under high-loading amounts but also facilitate the formation of heat conduction path with thermally conductive f-BNNS and Ti 3 C 2 T x . When the total loading amount of MXene, f-BNNS, and AgNWs was 50.5 wt% (MXene: 25 wt%, f-BNNS: 25 wt%, AgNWs: 0.5 wt%), the yield and ultimate tensile strengths of the f-BNNS/MXene/AgNWs/PBI-50/0.5 composite film reached ~204.8 and ~203.6 MPa, respectively. Meantime, the in-plane and through-plane TCs of f-BNNS/MXene/AgNWs/PBI-50/0.5 composite film also could reach ~31.97 and ~2.25 WÁm À1 K À1 with increases of ~52.2% and ~80% in comparison with those of f-BNNS/MXene/PBI composites, respectively, having the same contents of f-BNNS and MXene.
Aqueous zinc-ion batteries (AZIBs) use zinc metal as anodes are expected to be used for large-scale energy storage due to their good safety, low cost, environmental friendliness, etc. However, the zinc dendrite growth and associated side reactions seriously cause low Coulomb efficiency and reduce the cycle life of AZIBs, finally hampering further practical application. Herein, the γ-poly(glutamic acid) (γ-PGA)/aramid nanofibers (ANFs)/ MXene (PAM) protection layer was designed toward a dendrite-free Zn metal anode. The PAM layer with a three-dimensional (3D) network formed by strong hydrogen bonding interactions effectively inhibits the growth of zinc dendrites, corrosion of the electrolyte, and hydrogen precipitation due to the reduced nucleation overpotential, which facilitates uniform galvanization/de-zincification. At a current density of 0.1 mA•cm −2 and 0.1 mAh•cm −2 , the cycle life of PAM@Zn//PAM@Zn symmetric cell could extend to 3500 h. Meanwhile, the PAM@Zn//V 2 O 5 full cell could also exhibit a capacity retention of 82.49% after 1500 cycles at 1 C. This strategy of designing a polymer-based composite protection layer by integrating the advantages of different materials opens up more possibilities for the development of a dendrite-free Zn anode.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.