Lecture 06 Electrochemical Systems I Reference. 1.R. Memming, Semiconductor Electrochemistry, Wiley-VCH, 2000 (e-book) 2.A.J. Bard and L.R. Faulkner, Electrochemical Methods: Fundamentals and Applications, Wiley, J. O’M. Bockris, A.K.N. Reddy, and M. Gamboa-Aldeco, Modern Electrochemistry, Kluwer Academic/Plenum Publishers, 2000 Lecture note

Electrochemical Cells - Basic Principles of Operations -

Electrochemical Cell Components Anode: an electrode where oxidation reaction occurs Cathode: an electrode where reduction reaction occurs Electrolyte

Characteristics of Electrochemical Cells a. Conservation of Charge Charges may only be circulated around but not generated in the electrochemical cells. b. Local Electroneutrality The electrical neutrality condition is locally satisfied in the electrochemical cells. In mathematical terms, this condition is expressed as: Where z i is the number of electrons in the charge transfer of species i (for example, Z Cu = 2 for Cu 2+ ).

Notation to Describe Electrochemical Cells

Standard Electromotive Series

Standard Half Cell Electrode Potential

Calculation of Standard Electrode Potential Meaning of positive potential?

Faraday’s Law

A zinc-air cell consists of zinc metal as anode (fuel) and an air electrode (oxygen as cathode. The reaction product from this cell is ZnO. A current of 100 A is drawn from this cell. We know that M Zn = g/mol and M ZnO = g/mol + 16g/mol = g/mol. What are the rates of zinc dissolution and ZnO formation in g/s? An Example of Faraday’s Law

Electrolytes

Ion Transport in Solutions The conductivity of solutions The equivalent conductivity of solutions

Mobility & the Einstein relationship Supporting electrolyte

Interaction between Ions and Solvent - Solvation -

Next time Electrochemical Systems – Part II