Electroless Ag-plated sponges by tunable deposition onto cellulose-derived templates for ultra-high electromagnetic interference shielding

Highlights: • Highly conductive electroless silver plated cellulose composite sponges were obtained with maximum conductivity of 2288 S/m. • Surface and interior moiety of sponges still retained porous structure after condense deposition of Ag layer. • The highest total shielding effectiveness of 120.85 dB was obtained when plating time was 120 min. • Absorption-dominant shielding mechanism was obtained, helping to reduce secondary radiation pollution. Environmental-friendly cellulose-derived sponges were employed as porous templates to achieve uniform Ag deposition via a facile and economical electroless plating method. SEM and BET results confirmed an Ag layer was deposited on cellulose composite sponges without damaging the porous structure. XPS and XRD analysis demonstrated substantial interactions between porous substrates and Ag particles. When utilized as electromagnetic interference (EMI) shielding materials, a 3.2 mm thick silver-plated sponge exhibited a total shielding effectiveness (SE_total) value of as high as 120.85 dB in the frequency range of 10–1500 MHz when the plating time was 120 min. Moreover, the conductive sponges displayed absorption-dominant mechanism to alleviate secondary radiation, making them promising candidates as high EMI shielding materials.