Flexible Polyvinyl Alcohol/Reduced Graphene Oxide Coated Carbon Composites for Electromagnetic Interference Shielding

The proliferating market of electronic devices has driven the demand for efficient electromagnetic interference (EMI) materials to eliminate unwanted electromagnetic radiation. Despite great recent progress with graphene-based polymer composites, the facile preparation of cost-efficient and high-performance EMI shielding composites at low graphene loading has yet to be achieved. Herein, flexible polyvinyl alcohol/reduced graphene oxide coated activated carbon (PVA/RGO@AC) composite films with extremely low graphene amounts are prepared by using AC as segregators and substrates. Decoration of AC with graphene to create an individual RGO sheet coated AC structure leads to a dramatic increase in the conductivity of AC and effectively prevents the restacking and agglomeration of graphene. The percolation threshold of the PVA/RGO@AC composites is as low as 0.17 wt% for RGO@AC, and in particular, only 0.017 wt% RGO is needed. A high conductivity of 10.90 S/m and impressive electromagnetic interference shielding effectiveness (EMI SE) of 25.6 dB with an absorption-dominated mechanism are achieved for PVA/RGO@AC composites with a low RGO loading of 1.0 wt%. The specific EMI SE of the composite reaches 17.5 dB/mm, outperforming most of the reported pioneering graphene-based polymer composites with such low RGO amount. The excellent electrical property and outstanding EMI shielding performance are attributed to the internal well-constructed three-dimensional RGO-AC-RGO interconnected conductive network. Intriguingly, the fabricated composites exhibit a stable EMI SE even after 1000 bend-release cycles. These results demonstrate that our approach is a novel and promising method for producing highly conductive, high shielding performance and cost-effective materials with very low graphene loading.