Structural Engineering of Hierarchical Aerogels Comprised of Multi-dimensional Gradient Carbon Nanoarchitectures for Highly Efficient Microwave Absorption

Abstract

Recently, multilevel structural carbon aerogels are deemed as attractive candidates for microwave absorbing materials. Nevertheless, excessive stack and agglomeration for low-dimension carbon nanomaterials inducing impedance mismatch are significant challenges. Herein, the delicate “3D helix–2D sheet–1D fiber–0D dot” hierarchical aerogels have been successfully synthesized, for the first time, by sequential processes of hydrothermal self-assembly and in-situ chemical vapor deposition method. Particularly, the graphene sheets are uniformly intercalated by 3D helical carbon nanocoils, which give a feasible solution to the mentioned problem and endows the as-obtained aerogel with abundant porous structures and better dielectric properties. Moreover, by adjusting the content of 0D core–shell structured particles and the parameters for growth of the 1D carbon nanofibers, tunable electromagnetic properties and excellent impedance matching are achieved, which plays a vital role in the microwave absorption performance. As expected, the optimized aerogels harvest excellent performance, including broad effective bandwidth and strong reflection loss at low filling ratio and thin thickness. This work gives valuable guidance and inspiration for the design of hierarchical materials comprised of dimensional gradient structures, which holds great application potential for electromagnetic wave attenuation. "Image missing"

Flexible and Alternately Layered High‐Loading Film Electrode based on 3D Carbon Nanocoils and PEDOT:PSS for High‐Energy‐Density Supercapacitor

“…Notably, owing to the unique 3D helical morphology of CNC (the inset 2 of Figure 2b), the adjacent CNCs are in touch with each other via special point contact, which is distinguishing from the face contact between adjacent graphene sheets [ 32,33 ] and line contact between adjacent CNTs. [ 34,35 ] In contrast to the face and line contacts, the point contact between CNCs effectively prevents the agglomeration of CNCs [ 36,37 ] and consequently enhances the specific surface area [ 38 ] for fast transfer of electrolyte ions. In order to highlight the advantages of the unique 3D helical structure of CNCs, we also prepared (GO/PIL)‐1L and (CNT/PIL)‐1L as control samples by the same method, and recorded the morphologies of GO side (Figure S4a, Supporting Information) and CNT side (Figure S4b, Supporting Information), respectively.…”

Identification of the Intrinsic Dielectric Properties of Metal Single Atoms for Electromagnetic Wave Absorption

“…After removal of the NaCl templates, the 3D honeycomb-like structures were formed. Such interconnected structures with open pores endow the 3D M–N x Cs with a large surface area, which facilitates the improvement of the EMW absorption performance [ 21 ]. To gain information on the specific surface area and the porosity of the 3D honeycomb-like M–N x Cs, N 2 adsorption–desorption isotherms were measured.…”

Architecture Design and Interface Engineering of Self-assembly VS4/rGO Heterostructures for Ultrathin Absorbent

“…The pristine 2D rGO nanosheet has great potential to be designed as an ultrathin microwave absorbent but exhibits marginal microwave attenuation capability, which cannot bridge the gap of achieving enhanced microwave absorption. In order to cope with this issue, rGO microarchitectures with multiple winkles and microporous cavities are tailored and widely applied to promote microwave attenuation capability in virtue of the multiple reflections and scatterings of incident microwaves [ 18 – 20 ]. The elaborate rGO microarchitecture fully maintains the superior privileges of rGO by evading excessive stacks or agglomerations, which can greatly contribute to pursuing the ultrathin microwave absorbent [ 21 ].…”

“…The graphene layers were uniformly intercalated by three-dimensional (3D) helical carbon nanocoils, endowing the abundant microporous structure and better dielectric properties. The hierarchical multi-dimensional carbon-based aerogels showed the maximum reflection loss (RL) of − 55.1 dB and EAB of 5.6 GHz [ 18 ]. Gao et al designed graphene microflowers with highly microporous architecture.…”