This example shows how to use the Simscape™ example library ElectroChem_lib. In the model Fe3+ ions are reduced to Fe2+, and Pb is oxidized to Pb2+, thereby releasing chemical energy. The molar flow rate of lead ions is half that of the iron ions as two electrons are exchanged when Pb is oxidized to Pb2+. The chemical potential of the Pb source is by convention zero as it is a solid.
The electrochemical library defines the through variable as molar flow rate, and the across variable as chemical potential. This example is motivated by Pecheux, F., Allard, B., Lallement, C. & Vachoux, A. & Morel, H., "Modeling and Simulation of Multi-Discipline Systems using Bond Graphs and VHDL-AMS", International Conference on Bond Graph Modeling and Simulation (ICBGM), New Orleans, USA, 23-27 Jan. 2005