Sorry for the confusion.

\Yes, we are defining electrochemical reactions in the mixture template as below:

What I mean by "turn off the electrochemical model" is that I deactivate "Electrochemical" reactions under "Species Model" and also turn off "Potential/Li-ion Battery" under "Models". When we deactivated the electrochemical reactions and turned off "Potential/Li-Ion Batter", it worked well. 

For your reference, we have two phases (gas, liquid) in a 3D reactor design, and two electrochemical reactions only occur in electrolyte phase (liquid phase). We add a certain negative current density on an electrode where an electrochemical reaction occurs. We set the potential (V) on the other electrode to 0 in which the other electrochemical reaction occurs.

If you need more information, please let me know. 
Many thanks.