Stretchable Electrodes with Interfacial Percolation Network.

Abstract

Stretchable electrodes are an essential component that determines the functionality and reliability of stretchable electronics, but face the challenge of balancing conductivity and stretchability. Here, we propose a new conducting concept called the interfacial percolation network (PN) that results in stretchable electrodes with high conductivity, large stretchability, and high stability. The interfacial PN was composed of a two-dimensional (2D) PN and a protruding PN embedded on the surface and in the near-surface region of an elastic polymer matrix, respectively. The protruding PN was the key design to intimately link the 2D conducting channels on the surface of the elastomer with the 3D conducting channels in the bulk of the elastomer. The protruded PN was obtained by changing the arrangements of silver nanowires (AgNWs) from horizontal to quasi-vertical through introducing foreign polymer domains in the near-surface region of the polymer matrix. The resulting electrode achieved a conductivity of 13,500 S cm-1 and a stretchability of up to 660%. Its resistance changes (i.e., R/R0) under stretched conditions were orders of magnitude lower than those of conventional 2D PN and 2D + 3D PN. This electrode performed stability in various physicochemical conditions, including being soaked in acid and alkaline solutions for 20 days, heated at 80°C for 10 days, stretched to 80% for 10000 cycles, and scratched by a sharp needle. The concept of interfacial PN was broadly applicable to common conductors used in stretchable electronics, such as graphene, gold film, Ag film, and liquid metal. The conductivity of the interfacial PN electrode made from liquid metal remained at 46,750 S cm-1 after the electrode underwent multiple stretch-release cycles with a deformation of >600%. The concept of interfacial PN provides fruitful implications for the design of stretchable electronics. This article is protected by copyright. All rights reserved.