  Highly flexible electromagnetic interference (EMI) shielding material with
excellent shielding performance is of great significance to practical
applications in next-generation flexible devices. However, most EMI materials
suffer from insufficient flexibility and complicated preparation methods. In
this study, we propose a new scheme to fabricate a magnetic Ni particle/Ag
matrix composite ultrathin film on a paper surface. For a ~2 micro meter thick
film on paper, the EMI shielding effectiveness (SE) was found to be 46.2 dB at
8.1 GHz after bending 200,000 times over a radius of ~2 mm. The sheet
resistance (Rsq) remained lower than 2.30 Ohm after bending 200,000 times.
Contrary to the change in Rsq, the EMI SE of the film generally increased as
the weight ratio of Ag to Ni increased, in accordance with the principle that
EMI SE is positively related with an increase in electrical conductivity.
Desirable EMI shielding ability, ultrahigh flexibility, and simple processing
provide this material with excellent application prospects.
