Different Types of Electrodes

Introduction

Electrodes refer to a conductor by which electrical currents can be transmitted. These small devices are sometimes referred to as electrical conductors. It is a conductor used to make a junction with a nonmetallic part of a circuit. They are frequently used in electrochemical cells, semiconductors like diodes, and medical devices. William Whewell cast the word at the request of the scientist Michael Faraday. There are various types of electrodes.

What are Electrodes?

Electrodes are principal components of electrochemical cells. An electrode is a good conductor of electricity. Electrodes can be gold, platinum, carbon, graphite, metal, etcetera. In addition, they furnish the surface for oxidation-reduction reactions in the cells. Therefore, there are negative electrodes as well as positive electrodes.

Types of Electrodes

An electrode cannot be permanently established because it can take the character of an anode or cathode, depending on the electron flow direction. The other type is a bipolar electrode, which at the same time takes on the role of an anode of one cell and a cathode of the nearby cell.

There are a few things that we come across while dealing with the electrodes and the repeated terms we hear are cathode and anode.

Cathode – Negative Terminal

It is said to be the electrode where the reduction process occurs. The cathode is negative as the electrical energy that is contributed to the cell consequence in the decomposition of chemical compounds. Regardless of how it can also be positive, as in the case of a galvanic cell where a chemical reaction leads to the production of electrical energy.

Anode – Positive Terminal

An anode is an electrode through which the conventional current enters into a polarised electrical device. In electrochemistry, it is the point where an oxidation reaction occurs. In general terms, at an anode, negative ions or anions are prone to react and give off electrons due to their electrical potential. These electrons then move to and into the driving circuit. So, for example, if we take a galvanic cell, the anode is negative and the electrons largely move towards the outer part of the circuit.

Examples of electrodes

There are two types of electrodes, namely reactive and inert electrodes.

Reactive electrodes

Reactive electrodes are the electrodes that take part in the reaction taking place in the cell and can disassociate in the electrolyte.

The passage of electricity takes place through ion exchange.

Example – copper, silver, and gold.

Inert Electrodes

A metal that doesn’t interfere or participate in any chemical reactions is known as an inert electrode. However, it is still used to transfer electricity by passing electrons through the solution instead of exchanging ions.

Example – graphite, platinum, gold, and rhodium.

• Electrodes in Quantitative Analysis

In a potentiometric analysis, an indicator electrode responds to differences in the analyte’s activity or ”effective concentration”.

This simpleness makes potentiometry an economical technique set side by side to atomic spectroscopy or ion chromatography. Furthermore, these procedures can be broken down into several classifications depending on which aspects of the cell are controlled.

• Electrodes and batteries

Lead-acid batteries, electrodes pass on energy to and from the electrolyte to power the polarized device they connect. This energy departs from the battery through the negatively charged anode and proceeds through the device. Then it returns via the positively charged cathode, thereby bringing down the power stored through reduction.

This is the origin of the chemical reaction that batteries convert to electricity. Oxidation causes an increase of electrons on the anode. This restless energy wants to go somewhere, but the electron-deficient cathode is on the far side of the insulated electrolyte.

Batteries are bifurcated into primary and secondary forms:

Primary batteries

Primary batteries can be used till they are exhausted of energy then discarded. However, their chemical reactions, in general, can’t be reversed. Thus, they can’t be recharged. When the donation of reactants in the battery is exhausted, the battery stops manufacturing current and is not of use anymore.

Secondary batteries

Secondary batteries are rechargeable. It can reverse its chemical reaction when an electric current is applied to the cell. This regenerates the original chemical reactants to be cast, recharged and used several times.

Some rechargeable battery types are ready for use in identical sizes and voltages as disposable.

Electrodes in Electrolysis

Electrolysis is a simple process used to differentiate a substance into its original components or elements. From this process, a number of elements have been discovered in modern chemistry. In Electrolysis, an electric current is sent into and out of an electrolyte and into the solution to restore the flow of ions compulsory to run an otherwise non-spontaneous reaction.

Electrodes are immersed and separated at a distance. A current goes between them through the electrolyte and is connected to the power source, which completes the electrical circuit. A direct current [DC] supplied by the power source drives the reaction causing ions in the electrolyte to be attracted toward the oppositely charged electrode, Cathode, and Anode. The quantity of electrical energy that must be summed equals the change in Gibbs free energy of the reaction added to the losses in the system.

Quinhydrone electrode

Quinhydrone electrode is a different type of electrode consisting of a platinum wire in a solution containing quinhydrone used to determine hydrogen ion concentration. It is an important technique used to simplify the process. It proves to be very helpful.

This electrode is like another source of the commonly used glass electrode. However, it is unreliable above pH eight and cannot be used with solutions containing a powerful oxidizing or reducing agent.

Conclusion

Modified electrodes can be utilized as chemical sensors to observe organic and biological molecules of industrial and medicinal interest. Electrodes are a very important part of today’s life. They are used in various aspects of our routine life. Therefore, they cover a large part of the sector.

This experiment can be used to establish electroanalytical chemistry skills. The perspective is based on the electrode potentials, the vertical ionization potentials [oxidation], and the affinity to electrons [reduction].

The conclusion is drawn that most electron transfer reactions requiring organic compounds are reversible. The irreversibility of the net electrode reaction is due to the irreversibility of subsequent chemical and electrochemical stages.

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