The effect of MWCNTs on the electrical properties of a stretchable carbon composite electrode

Stretchable electrodes are of great interest with increasing demands for flexible electronic devices. Carbon black polymer composites do not show increasing resistivity during stretching, but resistivity decreases in a certain range. However, the electrical conductivity of carbon black is insufficient for electrodes. Multi-wall carbon nanotubes (MWCNTs) are carbon-based nanostructures that impart good electrical conductivity and flexibility with a high aspect ratio. CNTs may help to improve the electrical conductivity of carbon black. In this study, MWCNTs were added to a carbon black electrode with a simple process and then investigated. Adding MWCNTs introduced two benefits to the electrical properties of carbon black composites for use as a stretchable electrode. The addition of MWCNTs reduced the electrical resistivity of the carbon electrode as it connected non-contacting carbon black particles to enhance the effective conductive network. Also, MWCNTs minimized the increase in the resistance of the carbon electrode during stretching because they bridged separate carbon black aggregates and aligned along the stretching direction to enhance conductive path and inhibit crack growth. Additionally, the electrical resistance of MWCNTs in the carbon black electrode was maintained after repetitive stretching. A stretchable electrode showed stable electrical behavior under a strain of 25% after repetitive stretching.