Green electrochemical synthesis of graphene oxide for high-performance electromagnetic shields

This study presents an electrochemical procedure for synthesizing graphene oxide (GO) nanosheets in a diluted acidic medium (0.05 M), featuring 100% synthesis yield. Characterization results revealed that the synthesized GO in this approach exhibits a low XRD peak position (around 10(degrees)) and a C/O ratio of 2.9, offering higher surface functionality than conventional electrochemical methods reported in the literature. We also demonstrated the tunability of the GO's surface functionality by manipulating the synthesis parameters, such as electrolyte concentration and synthesis time, offering flexibility that surpasses the constraints often seen in chemical methods. Additionally, it was observed that assembling the current GO nanosheets into diverse microscopic (e.g., layered and porous) and macroscopic (e.g., paper and aerogel) structures results in distinctive characteristics and properties. Electromagnetic interference (EMI) shields with tunable specific EMI shielding effectiveness (SSE/t) and shielding mechanisms have been devised by fine-tuning the synthesis and processing methodologies. Excellent SSE/t ranging from 5000 dB cm(2) g(-1) for compact to 2000 dB cm(2) g(-1) for porous shields has been achieved, unraveling the importance of multi-scale materials design for the performance of the final products.