Lightweight silver@carbon microsphere@graphene (Ag@CMS@GR) composite materials for highly efficiency electromagnetic interference shielding properties

Abstract

In this article, lightweight silver@carbon microsphere@graphene (Ag@CMS@GR) composite materials were fabricated. First, carbon microsphere (CMS) was prepared by redox hydrothermal method in the presence of FeCl 3 and polyvinyl alcohol. Next, on the surface, silver was deposited to form Ag@CMS particles. And finally, the graphene sheets were added to connect Ag@CMS particles to obtain Ag@CMS@GR composites. Because of the silver nanoparticle may form a conductive pathway, Ag@CMS with relative high content of silver nanoparticles show superior EMI shielding properties. Next, graphene was introduced into Ag@CMS with relative low content of silver particles to form Ag@CMS@GR composites, which is helpful for decreasing the apparent density of composites to around 1.01 gÁcm −3 . And the composites also show good EMI shielding properties. The highest SE and specific SE values of Ag@CMS@GR reached 39.26 dB and 38.87 dBÁcm 3 Ág −1 with 5 wt % graphene content. The EMI shielding mechanism of Ag@CMS@GR composites was discussed. It can be potentially used for lightweight EMI shielding applications.Conductive polymers also can be used as matrix for lightweight EMI shielding materials. Polymer metal composites and conductive polymers usually are lightweight, which is always vital factor for the practical EMI shielding application. Compared with other polymer matrix, carbon microspheres (CMSs) have been attracted a great deal of attention in view of relatively low cost, large surface area, excellent corrosion resistance, and low density. It also has extensive application in electrode materials, 18,19 catalyst supports, 20 supercapacitors. At the same time, the preparation of CMSs by hydrothermal method is not complicated. In our laboratory, we have ever prepared a series of PVA CMSs by redox Additional Supporting Information may be found in the online version of this article.

Recent advances and perspectives on silver-based polymer composites for electromagnetic interference shielding

“…It is worth noting that high electrical conductivity, which depends on the type, morphology and distribution of conductive fillers, is an important prerequisite for obtaining high-performance CPC-based EMI shielding materials. Some preeminent conductive fillers, including carbon nanotubes (CNTs), [3][4][5] graphene, [6][7][8] MXenes, [9][10][11][12] metal nanoparticles, 13,14 and metal nanowires, 15,16 have been widely used to improve the EMI SE of polymer matrices. The results confirm that in the case of CNTs and graphene, their main limitation is the difficulty in achieving theoretical electrical conductivity in the resulting composites.…”

Room-Temperature One-Step Synthesis of Silver/Reduced Graphene Oxide Nanocomposites as an Excellent Microwave Absorber

“…Recently, carbon-based materials, such as carbon black, carbon nanofibers, carbon nanotubes, graphene, graphene oxide (GO), and reduced graphene oxide (RGO) have attracted extensive attention as EMI-shielding materials. ,− Among these, GO provides a hydrophilic surface comprising a large number of negatively charged oxygen-containing functional groups available for the strong electrostatic interactions with positively charged metal ions . An Ag/GO composite provides favorable properties, such as low density, good dispersion, corrosion resistance, electrical conductivity, easy processing, and synergistic effects. ,− Additionally, the properties of Ag decorated on RGO nanocomposites also received much attention due to its wide range of applications in the field of sensing, catalysis, heavy metal detection, optoelectronics, EMI shielding, and as an antibacterial agent. , Therefore, combining carbonaceous materials with Ag is considered a right approach for the formation of their nanostructured composites for achieving effective EMI shielding. ,,− …”

“…These investigations revealed that the preparation procedures of most of these materials are not environmentally friendly due to the requirements for hazardous chemicals, such as hydriodic acid, trisodium citrate, sodium citrate, sodium borohydride (NaBH 4 ), and hydrazine hydrate , and harsh high-temperature conditions, such as 90 °C, 100 °C, ,,, 120 °C, 156 °C, and 180 °C . Additionally, the involvement of multisteps in several preparations provided additional challenges.…”

Hierarchical Porous Film with Layer-by-Layer Assembly of 2D Copper Nanosheets for Ultimate Electromagnetic Interference Shielding

“…This approach generally leads to multiple internal reflections by maximizing the travel path of the electromagnet (EM) in a shielding system. Microsphere structures that are composed of hollow spherical cores and conductive shells have been intensively studied. − Those porous films with spherical internal architectures have been prepared by complicated extra coatings of metallic materials (Ni, Cu, Co, Ag, or carbon-based two-dimensional (2D) nanomaterials). − Although those films exhibited enhanced EMI SE performance compared to conventional dense metallic films or foils, advanced architecturing of the internal structure and material design was required to achieve an extraordinary shielding performance with a high reliability.…”