Researchers from Korea have shown that single-layer graphene is an excellent high-performance electromagnetic interference (EMI) shield. They used CVD-synthesized graphene, and have found that it features seven times greater EMI shielding effectiveness (in terms of dB) than gold film of the same thickness.
The researchers say that an ideal single-layer graphene can shield as much as 97.8% of incident waves (!) - the most effective material in terms of effectiveness per mass. The actual graphene sheet they used shielded about 40% of incident waves.