Introduction to Electrochemical Science and Engineering

Serguei N. Lvov is a professor of energy and mineral engineering, a professor of materials science and engineering, and a director of the Electrochemical Technologies Program at the EMS Energy Institute of The Pennsylvania State University, University Park, USA. His areas of research include electrochemistry, thermodynamics, material sciences, and environmental sciences. He is the author of more than 100 peer-reviewed papers, 2 books, 6 book chapters, and 2 US patents.

Acknowledgments


Introduction


Author


Electrolyte Solutions


Objectives


Formation of Electrolyte Solutions


Electrolyte Concentration and Concentration Scales


Conversion Equations for the Concentration of Solutions


Chemical Potential


Standard Chemical Potential and Activity Coefficient on Different Concentration Scales


Chemical Potential of Solvent and Solute in Electrolyte Solution


Activity and Activity Coefficient


Activity Coefficient of Electrolyte and an Ion


Chemical Potential and Gibbs Energy of Formation


Debye–Hückel Theory of Dilute Electrolyte Solutions


Calculation of Activity Coefficient Using Debye–Hückel Theory


Calculated and Observed Activity Coefficients


Mean Activity Coefficient in Concentrated Aqueous Solutions


Speciation in Weak Electrolytes


pH of Aqueous Solutions


pH of Buffer Solutions


Suggested pH of Standard Solutions


Summary


References


Electrochemical Cells


Objectives


Basic and Derived SI Units


Electrochemical Cell (System)


Electrolytic and Galvanic Cells


Electrochemical Diagrams (Traditional)


New Electrochemical Diagrams


Faraday’s Law of Electrolysis


Fundamental Constants


Water Electrolysis


Ohm’s Law


Kirchhoff’s Law


Electrochemical Cells with Transfer


Daniell Cell in Galvanic Mode


Daniell Cell in Electrolytic Mode


Cell Potential-Current Dependence


Summary


References


Electric Conductivity


Objectives


Types of Electric Conductivity


Significance of Ion Conductive Materials for Electrochemical Engineering


Origin of Ionic Conductivity


Conductance and Conductivity of an Electrolyte


Electric Conductivity of Pure Water


Conductance by Direct and Alternating Currents


Electrode/Electrolyte Interface


Extracting the Electrolyte Resistance


Conductivity Measurements


Molar and Equivalent Conductivity


Kohlrausch’s Law and Limiting Conductivity


Additivity of Electrolyte Limiting Conductivity


Transport Numbers


Diffusion and Hydration of Ions in Infinitely Diluted Solution


Proton Conductivity


Walden’s Rule


Summary


References


Equilibrium Electrochemistry


Objectives


Equilibrium Thermodynamics and Electrochemistry


Equilibrium between Phases in Electrochemical Cell


Galvani Potential of the Hydrogen Electrode


Gibbs Energy of Reaction and Equilibrium Electrode Potential


Nernst Equation


Standard Hydrogen Electrode


Ag/AgCl Reference Electrode


Harned Cell


Electrochemical Series


Calculation of Equilibrium Potential of Daniell Cell


Nernst Equation for Typical Electrodes


Another Example of Estimating of E0 and E


Calculation of E0 at Elevated Temperature


Temperature Dependence of the Standard Electrode Potential


Temperature Dependence of Open Circuit and Decomposition Potentials


Potential-pH (Pourbaix) Diagram


Summary


References


Electrochemical Techniques I


Objectives


Potentiometric Measurements


Commercial Ag/AgCl Reference Electrode


Commercial Calomel Reference Electrode


pH Glass Electrode


Liquid Junction (Diffusion) Potential


Henderson Equation


Calculation of the Diffusion Potential


Minimization of the Diffusion Potential in a Cell


Kinds of Potentiometry


Measurement of the Standard Electrode Potential


Measurement of pH


Combined pH/Reference Electrode Sensor and pH Meter


Summary


References


Electrochemical Kinetics


Objectives


Concept of Electrochemical Cell Overpotential


Overpotential of a Single Electrode


Polarization Curve of a Single Electrode


Mechanism of Electrochemical Reaction


Charge Transfer Overpotential: Butler–Volmer Equation


Symmetry Coefficient, β


Exchange Current Density, jo


Experimental Data on the Exchange Current Density and Symmetry Coefficient


Simplifications of Butler–Volmer Equation


Tafel Equation


Volcano Plot


Concentration Overpotential


Mass Transfer Overpotential


Generalized Butler–Volmer Equation


Summary


References


Electrochemical Techniques II


Objectives


Transport Processes in Electrochemical Systems


Current–Time Dependence at Constant Potential (Potentiostatic Regime)


Concentration–Time Dependence at Constant Current (Galvanostatic Regime)


Effect of Hydrodynamics (Fluid Mechanics) on Electrochemical Reaction


Rotating Disk Electrode and Limiting Current


Rotating Disk Electrode Electrochemical Cell


Cyclic Voltammetry Background


Cyclic Voltammetry of Fe(CN)3–6 /Fe(CN)4–6 Couple


Summary


References


Electrochemical Energy Conversion


Objectives


Main Types of Electrochemical Energy Conversion Systems


Principle Design of a Fuel Cell


Main Kinds of Fuel Cells


Electrochemistry of Full Cells


Three-Phase Boundary Issue


New Electrochemical Diagrams for Fuel Cells


Polarization Curves of PEMFC and SOFC


Efficiency of Fuel Cell vs. Heat Engine


Total Efficiency of Fuel and Electrolytic Cells


Heat Balance in Fuel and Electrolytic Cells


Summary


References


Electrochemical Corrosion


Objectives


Origin of Electrochemical Corrosion


Pourbaix Diagram in Corrosion Science


Polarization Curve of Metal Corrosion


Corrosion Potential and Current Density


Rate of Electrochemical Corrosion


Corrosion Protection


Kinds of Corrosion


Summary


References


Data Section


Codata Values of the Fundamental Physical Constants


Physical Constants of Inorganic Compounds


Standard Thermodynamic Properties of Chemical Substances


Thermodynamic Properties as a Function of Temperature


Thermodynamic Properties of Aqueous Ions


Ionization Constant of Water as a Function of Temperature and Pressure


Electrical Conductivity of Water


Electrical Conductivity of Aqueous Solutions


Standard KCl Solutions for Calibrating Conductivity Cells


Molar Conductivity of Aqueous HCl


Equivalent Conductivity of Electrolytes


Ionic Conductivity and Diffusion at Infinite Dilution


Electrochemical Series


Dissociation Constants of Inorganic Acids and Bases


Dissociation Constants of Organic Acids and Bases


Activity Coefficients of Acids, Bases, and Salts


Mean Activity Coefficients of Electrolytes


Concentrative Properties of Aqueous Solutions


Aqueous Solubility of Inorganic Compounds at Various Temperatures


Solubility Product Constants


Solubility of Common Salts at Ambient Temperatures


Thermophysical Properties of Water and Steam at Temperatures up to 100°C


Vapor Pressure and Other Saturation Properties of Water at Temperatures up to 100°C


van der Waals Constants for Gases


Vapor Pressure of Saturated Salt Solutions


Electrical Resistivity of Pure Metals


Composition of Seawater and Ionic Strength on Molality Scale at Various Salinities S in Parts per Thousand


Error Function


Periodic Table of Elements


Appendix A: Quizzes


Appendix B: Video-Based Assignments


Index