Between an electrode and an electrolyte there exists an interfacial potential difference.
Many authors give the electrode potential to be the electric potential of the electrode relative to the electrolyte. I have a few problems with this, and was wondering whether anyone could help.
We define the electrode potential of SHE to be 0V. It is impossible to measure the interfacial potential difference, however nevertheless one certainly exists between the reference electrode and the solution. Are we saying that we define the interfacial potential difference of the SHE to be zero, and then have electrode potentials of other couples as interfacial potential differences measured relative to this interfacial potential difference?
To my mind, this cannot be right. Don't we just set our zero reference (i.e. one end of our voltmeter) of electric potential at the electrode of the SHE, and measure electric potentials of other electrodes relative to this?
Sergio Trasatti wrote this regarding electrode potentials,
Equation (4.7) shows that the "electrode potential", as obtained in practice, does not measure the electric potential drop between the bulk of the metal and the bulk of the solution, but it is a more complex quantity which includes both electrical and chemical contributions.
Why do so many authors conflate interfacial potential differences and electrode potentials? Or am I missing something here? Thank you!