Electrode recovery potential

Abstract

In some instances the same electrodes are used for stimulation and then for recording a bioelectric event immediately after the stimulus. However, after the current pulse there remains an electrode potential that decays quasiexponentially. We have designated this falling potential the electrode-recovery potential. This study investigated the recovery potentials of single electrodes of rhodium, stainless steel, platinum and platinum-iridium in contact with 0.9% saline at room temperature (25 degrees C) over a current density ranging from 0.1 to 100 mA/cm2 using a constant-current pulse. In all cases, with increasing current density, there was a decrease in the time for the electrode potential to fall to one half of the immediate post-stimulus value. Above about 20 mA/cm2 the decrease in recovery time was smooth with increasing current density. Below 20 mA/cm2, the recovery time was slightly irregular. The shortest recovery times were for platinum and platinum-iridium. The largest decrease in recovery time with increasing current density was for stainless steel, which decreased 10 fold from 0.1 to 100 mA/cm2. The recovery time for rhodium decreased about three-and-one half fold over the same current density range. It was found that the waveform of the recovery potential is not a simple exponential because the Warburg and Faradic components of the electrode-electrolyte interface are current-density dependent. In general, for all current densities studied (0.1-100 mA/cm2), there was a sudden initial fall in electrode potential with cessation of current flow, followed by a very gradual nonexponential decrease in potential.

Calculation approach for current–potential behaviour during pulse electrodeposition based on double-layer characteristics

“…it drops and then slightly increases to reach the equilibrium state. This again, seems to be in accordance with Mayer et al 39 Further work will be done in this respect to facilitate the prediction of the system's transient behaviour also for longer time spans. This may include the integration of effects such as, nucleation, 24,25 initial stage behaviour 26 and transport phenomena 27 to cover electrolytes with lower ion concentrations.…”

“…A possible reason is the explained intermediate state of ionic species, which means that charge carriers (ions) are present at the electrolyte/electrode interface that may react or change their charge even if the driving power of the electrodeposition process is turned to zero. The transient behaviour of the electrode potential after a current pulse has been examined by Mayer et al 39 and supports this assumption.…”

Electrically Evoked Compound Action Potentials Recorded From the Sheep Spinal Cord

“…The origins of artifact are not well understood but can completely obscure the response. The artifact is proportional to the stimulation, whereby high stimulation currents and pulse widths result in high electrical artifact .…”

“…Evoked responses can be detected when they appear later in time than the artifact, or when the signal‐to‐noise ratio (SNR) is sufficiently high. Depending on the stimulation and recording system, the artifact may be last for one, tens, or hundreds of milliseconds after the stimulus , but provided the neural response is detected after this window, neural evoked response data can be obtained. This is the case in surgical monitoring where there are large distances (tens of centimeters) between the stimulating and recording electrodes.…”