Electrochemical Cell
Introduction
An electrochemical cell is a device that generates electrical energy from chemical reactions or facilitates chemical reactions through the introduction of electrical energy. It is a fundamental component in various technologies, including batteries, fuel cells, and certain types of sensors.
Structure of an Electrochemical Cell
An electrochemical cell typically consists of two electrodes - an anode and a cathode, and an electrolyte solution. The anode is the electrode where oxidation (loss of electrons) occurs, while the cathode is the electrode where reduction (gain of electrons) occurs. The electrolyte is a substance that contains free ions and can be a solid, liquid, or gel.
Types of Electrochemical Cells
There are two main types of electrochemical cells: galvanic cells and electrolytic cells.
Galvanic Cells
Galvanic cells, also known as voltaic cells, generate electrical energy from spontaneous redox reactions. They are commonly used in batteries.
Electrolytic Cells
Electrolytic cells, on the other hand, use electrical energy to drive non-spontaneous redox reactions. They are used in processes such as electroplating and electrolysis.
Electrochemical Reactions
Electrochemical reactions involve the transfer of electrons between chemical species. These reactions are classified as redox (reduction-oxidation) reactions. In an electrochemical cell, the anode and cathode facilitate these reactions.
Electrochemical Cell Notation
The cell notation is a shorthand method of representing the reactions in an electrochemical cell. It is written as:
Anode | Anode electrolyte || Cathode electrolyte | Cathode
Thermodynamics of Electrochemical Cells
The thermodynamics of electrochemical cells is governed by the Gibbs free energy change of the cell reaction. The cell potential, also known as the electromotive force (EMF), is directly related to the Gibbs free energy change.
Applications of Electrochemical Cells
Electrochemical cells have a wide range of applications. They are used in batteries, fuel cells, electrolysis, electroplating, corrosion prevention, and various types of sensors.