Multi‐Scale Silver Particle Morphology Combination to Enhance Electrical Percolation for Stretchable Conductive Inks

ABSTRACT Printed electronics represent an expanding field that increasingly requires high‐performance inks. Stretchable conductive inks are particularly relevant for applications in wearable electronics and in conformable health devices. These inks must combine mechanical deformability with the best possible preservation of electrical performance under deformation, relying on an optimized percolated network to remain functional during use. In this work, a stretchable and screen‐printable conductive ink formulated with silver particles and a vehicle composed of nanocellulose and hydroxypropyl methylcellulose (ensuring flow behavior, dispersion, and stabilization) is concerned. The key focus is the percolation network optimization through the strategic mixing of metallic particles. Three distinct morphologies of micrometric silver particles are combined to build a densely packed conductive network, enhancing the number of percolation pathways and ensuring electrical percolation with minimal resistance variation over strain. Additionally, high aspect ratio particles, specifically silver nanowires, are incorporated to reinforce interparticle electrical contacts through the network and further enhance conductivity stability. As a result, this approach yields an ink containing only 50 wt.% of silver, exhibiting a sheet resistance of 300 ± 40 mΩ/sq, capable of being stretched over 100% strain and enduring to at least 100 cycles at 25% strain while maintaining electrical percolation.