Short answer is "no". You need to have a conductive (ions) path between at least 2 electrodes, preferably 3, and the humid environment alone will not do that.

Longer answer... Electrochemistry still happens in those conditions (obviously). Generally it proceeds by having both oxidation and reduction reactions taking place at different locations on the same electrode. I'm not entirely clear on what is happening in your case, but it seems like you are suggesting slow migration of metal ions from the anode to the cathode through that thin aq layer which exists in humid conditions. That to me reads as though there is some continuous surface with 2 isolated electrodes on it, and in that case the answer may be yes. You would need to have a 3rd electrode (embedded) on that surface, so you could independently control the potential. Even still, the current paths and iR drop are going to make things difficult, and so this is not something that would definitely work.

Jacob Ketter I had typed out a nice detialed response and manged to delete it. So at some humidity level the adsorbed water layer forms a cohesive layer between the electrodes. Currently most work is done using a DC test at either 85C/85%RH or 40C/90%RH. The electrodes are biased typically 5-20 VDC for a week and the resistance is measured every 20 min or so. When there is no contamination present resistances are around 1-100 GOhm. When there is contamination the resistance starts out slightly lower (100 MOhm to 1 GOhm). As time progresses metals dissolve, migrate, and plate out. This creates a conductive path that decreases the resistance. At some point a dendrite starts growing, rapidly decresin resistance, until it shorts out the cell. I am interested in the cases with contamination.

Some other studies place a drop of water bridging the two electrodes. This makes life easier, but it also would obviously change how ions diffuse. There are also occasional papers that use EIS with the high humidity (no water drop). Some have used contamination, some have not. I've got a few citations below. What I'm interested in is measuring the diffusion coefficents of the various ions, and the voltages needed for the metals to dissolve or precipitate. So more of a mechanistic view.

One thought I did have is have the electrodes as close together as possible and placing a very thin Pt wire between them, close to one electrode, to serve as a quazi RE. Ag can't be used as it will form dendrites and short. Right now both electrodes are the same material but one could be changed to Au or Pt.

Contaminated

1. Zou, L. C.; Hunt, C., Characterization of the Conduction Mechanisms in Adsorbed Electrolyte Layers on Electronic Boards Using AC Impedance. Journal of The Electrochemical Society 2009, 156, C8-C15.

1. White, J. R., Conduction mechanisms in contaminant layers on printed circuit boards. IBM Journal of Research and Development 1993, 37 (2), 243-248.

Not contaminated

1. Takahashi, K. M., Conduction Paths and Mechanisms in FR‐4 Epoxy/Glass Composite Printed Wiring Boards. Journal of The Electrochemical Society 1991, 138, 1587-1593.