Introduction to Battery Technology
Introduction to Electrochemistry
Chemical Reactions and Electricity
At its heart, electrochemistry is the study of how chemical energy can be converted into electrical energy, and the other way around. It’s the science behind how a battery powers your phone or how corrosion happens on a metal fence. It all comes down to chemical processes that cause tiny charged particles called electrons to move.
This movement of electrons is what we call electricity. When we harness a chemical reaction that naturally wants to push electrons from one place to another, we can create a flow of electricity. This all takes place inside a device called an electrochemical cell.
Inside an Electrochemical Cell
Think of an electrochemical cell as a tiny factory designed to manage a specific chemical reaction. It has three essential parts that work together to create an electrical current.
The first two parts are the electrodes, which are typically pieces of metal. Each cell has two types:
Anode
noun
The electrode where oxidation occurs. It releases electrons into the external circuit. It is the negative terminal in a spontaneous cell like a battery.
Cathode
noun
The electrode where reduction occurs. It accepts electrons from the external circuit. It is the positive terminal in a spontaneous cell.
The third key component is the electrolyte.
Electrolyte
noun
A substance, usually a liquid or gel, containing ions that can move. The electrolyte allows charge to flow between the anode and cathode inside the cell, completing the electrical circuit.
Without the electrolyte, the ions couldn't move between the electrodes, and the whole process would grind to a halt. It's the bridge that allows the chemical reaction to continue.
The Core Reaction
The chemical reactions that power an electrochemical cell are called oxidation-reduction reactions, or redox reactions for short. In a redox reaction, electrons are transferred from one substance to another. The reaction is split into two halves: oxidation and reduction.
Oxidation is the loss of electrons.
Reduction is the gain of electrons.
A helpful way to remember this is the mnemonic OIL RIG. It stands for Oxidation Is Loss, Reduction Is Gain (of electrons).
In electrochemistry, students can remember the direction of electron transfer by thinking about an OIL RIG: Oxidation Involves Loss, Reduction Involves Gain.
In our cell, the substance at the anode gets oxidized, losing electrons. These electrons travel through the external wire to the cathode. There, a different substance gets reduced by accepting those same electrons. Oxidation and reduction are a matched set—you can't have one without the other. This coordinated transfer of electrons from the anode to the cathode is what generates a useful electric current.
What is the primary study of electrochemistry?
In an electrochemical cell, the electrode where oxidation occurs is called the ________.
These are the fundamental building blocks of electrochemistry. By arranging different materials for the anode, cathode, and electrolyte, chemists can design cells that power everything from tiny hearing aids to electric vehicles.