Fabrication of a 3D Porous Silver Wire Based on a Template-Assisted Electroless Deposition Method

Porous metal wires are promising in various applications, such as catalysis, energy storage and conversion, electrochemical sensing, and so forth. However, controllable fabrication and structural tuning of porous metal wires remains a daunting challenge. Here, we report the fabrication of 3D porous silver wires based on a template-assisted electroless deposition (ELD) method using an electrospinning-derived elastomer yarn as the template. After the calcination, the elastomer yarn with the deposition of silver nanoparticles can be converted into a 3D porous metallic silver wire with a conductivity higher than 3600 S/cm and a porosity of 86%. The porous structure of the wire could be tuned by changing the repeating cycles of the ELD process for loading silver nanoparticles. More importantly, the electrospinning-based fabrication strategy enables us to incorporate an insulating fibrous layer on the silver wire to impart advanced functionalities. As a proof of concept, a porous silver wire containing a concentric layer of SiO2 microfibers was prepared, and its application as a wire-shaped capacitor for liquid sensing was demonstrated. Benefitting from its completely inorganic nature, high porosity, and chemical stability, the composite wire could sense various organic solvents as well as aqueous solutions with high sensitivity, reliability, and long-term-use stability.