Electrochemical characterisation of new textile electrodes based on a conductive silicon yarn for bioelectrical stimulation

Transcutaneous electrical stimulation for therapeutic applications relies on electrodes that interface with the human skin. Alongside hydrogel and rubber electrodes, textile electrodes are becoming increasingly important. We introduce a novel textile electrode based on conductive silicone yarn and analyse the electrochemical characteristics. We consider two realisations of the electrode, one with a snap lead button and one where the yarn itself is used for contacting to a cable. Characterisation was done in contact to 0.9% sodium chloride solution. Impedance spectroscopy was performed over 24 h in the frequency range from 0.1 Hz to 1 MHz. Open-circuit potential measurements were taken over 12 h. Voltage and current noise were analysed in the time domain for one hour, and the power spectral density was calculated for a frequency range from 0 to 500 Hz. Our new textile electrodes showed median impedances of 19.6 kΩ at 0.1 Hz and 98 Ω at 1 MHz, which are similar or lower compared to previously introduced stimulation electrodes. The conductive silicone yarn exhibited higher impedances. Noise characteristics and potential stability of the electrodes and the electrode material were comparable to conventional types. In addition to their electrochemical performance, the new textile electrodes offer the skin compatibility of rubber electrodes and the high comfort of textile electrodes, rendering them a promising, sustainable and user-friendly alternative for bioelectrical stimulation applications.