Batteries, the technological development that changed mankind's modern life

Today, the lifestyle of human beings would be unimaginable without portable devices, whose development converges on their energy source, i.e. their battery (Figure 1). This device, whose function is to store electricity, is intimately linked to the development of electrochemistry, a very important branch of science that studies the transformations between chemical energy and electrical energy combining both chemical and electrical properties.

Figure 1. Composition of a common cell or battery

Archaeological evidence has demonstrated the existence of a primitive battery from the period of the Parthians, a period known as Hellenistic because art and science had a boom in the great cities of Parthia (between 248 BC and 226 AD), which was called the Baghdad battery, which was composed of a ceramic vessel, a copper tube and a sheet of iron, it is speculated that it was used for medicinal purposes. Decades later (1600), the English scientist William Gilbert, known as the "father of magnetism", began to devise methods to strengthen magnetism in magnets; during the development of this study he introduced the term electricity from the Greek word elektron (amber).

A turning point in the study of electricity came with Benjamin Franklin (1752), world-renowned for his experiment with a comet (Figure 2). The scientist used a silk kite with an iron bar at its tip, from which a string attached to a key and a Leyden bottle (capable of storing electric charge) descended. When lightning struck the kite, Franklin realized that the Leyden bottle was charged with electricity; this design would later be used around the world for today's lightning rods that attract the lightning discharge to the earth.

In addition to this great invention, Franklin also coined the Principle of Conservation of Electricity, which states that "electricity is a single fluid or electric fire that passes from one body to another in the discharge".

Benjamin Franklin performing his famous experiment with a kite during a thunderstorm.

From these experiments, the scientific method has evolved to the development of modern electrochemistry. In 1800, Alessandro Giuseppe Antonio Anastasio Volta performed experiments that consisted of alternating silver and zinc disks, one on top of the other, forming a cylinder of disks, thus demonstrating what would become the first electrochemical battery. His contribution laid the foundations for concepts such as corrosion (oxidation of metals) or sacrificial anodes (a protective component used to protect structures submerged in water or buried from corrosion). In Volta's honor, the International System of Units includes the Volt, which is the unit of electromotive force or electric potential.

Figure 3. Electrochemical Volta Battery

With the first equations proposed by the Frenchman André-Marie Ampere, where he describes the relationship between the magnetic field and the electric current, George Ohm (1827), who is considered the Mozart of electricity, enunciated the well-known Ohm's Law, which involves the concept of resistance, that is, the difficulty that charges have to flow inside the conductor. Beyond this, this principle describes for the first time a clear proportional relationship between electric current and electric potential, and inversely proportional between electric current and resistance.

In 1836, nine years after Ohm's Law, John Frederic Daniell invented the first modern battery (Figure 3a) which consisted of a zinc rod immersed in a zinc sulfate solution and another copper rod immersed in a copper sulfate solution. The two solutions were separated by an earthenware vessel that did not allow the two solutions to mix, although it did allow ions to pass through it, acting as what is known today as a salt bridge.

As a replacement for the Daniell pile, invented in 1836 by John Frederic Daniell, a British chemist and meteorologist, Sir Williams Robert Grove, in 1839, developed the fuel cell, where he replaces the copper rod in the Daniell pile with a platinum rod (Figure 3b). As we know, platinum is an expensive metal, so Robert Wilhelm Eberhard Bunsen (1840) proposed using a carbon rod instead of platinum (Figure 3c).

Later, 33 years later to be exact (1873), Josiah Latimer Clark creates the first wet cell, i.e., where he uses an electrolyte solution inside the cell, and still using zinc, then the principle is as in the batteries already mentioned, but in this case the carbon rod is replaced by mercury (Figure 3d). The variation of Georges Leclanché, a scientist and engineer who used carbon, made the battery less expensive compared to the previous ones.

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Figure 4. a) Daniell stack; b) Grove stack; c) Bunsen stack and d) Clark stack.

A common aspect in all these cells was that both the anode (where oxidation takes place) and the cathode (where reduction takes place) used aqueous solutions, which implied an important technological limitation. Carl Gassner came to improve Leclanché 's pile by building the first "dry" pile in history. This contained a manganese dioxide gypsum paste in a less aqueous medium than in a "wet" cell; but Glassner had not used the term properly until Ludwig Mond and Charles Langer introduced the term "fuel cell" and solved the problems of past cells.

James Drumm (1926-1931) began his research on nickel-zinc alkaline batteries and Thomas Bacon invented the first fuel cell. In 1957, Karl Kordesch, Paul A. Marsal and Lewis Urry filed the patent for the alkaline (potassium hydroxide as electrolyte) dry cell battery, which became the Eveready Energizer D-size battery.

In 1960 Stanley Whittingham, researched with superconducting materials and culminated in a lithium battery with a titanium disulfide cathode and a lithium metal anode, but it was too explosive. Then John Goodenough (1980) indicated that the cathode would have greater potential if it were made with a metal oxide instead of a metal sulfide, and giving improvements to these two proposals Akira Yoshino creates the first commercial lithium-ion battery, commercializing it globally by 1991. In 2019 these three researchers were awarded the Nobel Prize in Chemistry for the development of this battery (Figure 5).

Figure 5. Lithium-ion Battery

Today, lithium-ion batteries have marked a turning point in technological and scientific development. The development of new batteries is still based on them, such as lithium ferro-phosphate (LFP) batteries, first described in 1996 and marketed in new-generation electric cars from 2021 in Eastern countries. Although some believe that aluminum-based batteries will replace lithium batteries, the fact is that the development of human life will continue to be closely linked to the evolution of these devices for many generations to come.