Lightweight Silver Nanowire Aerogel for Electromagnetic Interference Shielding

The fast development of highly integrated circuit packaging electronics generates electromagnetic pollution, causing harmful effects on the performance of the facility and the health of human. Thus, there is an increasing demand for electromagnetic interference (EMI) shielding materials. Metals are traditional EMI shielding materials with extremely high EMI shielding effectiveness (SE) because of their high electrical conductivity. However, the disadvantages of metals, including high density, poor corrosion resistance and poor workability, restrict their use. At present, carbon materials (such as graphene, CNF, and CNTs) are widely used to prepare EMI materials because of their high flexibility and conductivity. However, the complex synthesis process of carbon-based fillers and poor dispersion limit their application. Recently, silver nanowires are considered excellent fillers for the preparation of EMI materials due to their excellent conductivity, dispersibility and flexibility. Herein, we prepared silver nanowire aerogels by the method of freeze casting and freeze drying. The aerogel has an ultralow density below 5 mg/cm3 and the porosity is as high as 99.3%. The conductivity of aerogels is further enhanced with the treatment of NaCl solution. The EMI SE of the aerogel approaches 75.2 dB at a thickness of 4 mm due to the interconnected three-dimensional network structure and excellent conductivity of 28368 S/m.