(ORDO NEWS) — Cells have come a long way from unstable and sometimes even dangerous room-sized installations to compact and very capacious power sources. Let’s talk about the main milestones of this path.
For 200 years, mankind has managed to make a huge step forward in the creation of new current sources. Here are the most important steps that made it possible
February 18 is World Battery Day. We usually do not think about this invention, but galvanic cells – batteries and accumulators – surround us everywhere. Without them, your iPhone would run from a wall socket, like all other devices that we can carry with us today.
But the battery is almost 222 years old – over this long history, current sources have changed a lot, but their rapid growth has only been observed in the last few years – it is driven by the growing demand for electric vehicles. Let’s talk about the main stages in the development of galvanic cells.
The invention of the first galvanic cell by Alessandro Volta was preceded by the experiments of Luigi Galvani on the preparation of frog legs fixed on copper hooks with a steel scalpel, during which dead muscles contracted.
Alessandro Volta presented his current source to the Royal Society of London in 1800, naming it the galvanic cell after Luigi Galvani. The demonstration of the work of the pillar made a splash and Volta was even invited to Paris by Napoleon Bonaparte himself.
In 1836, John Frederick Daniel developed the idea of Alessandro Volta, presenting his own galvanic cell, which made it possible to overcome the polarization of the electrodes.
Oddly enough, it consisted of a piece of a bull’s esophagus, in the center of which was a zinc rod, and the esophagus itself was filled with dilute sulfuric acid. It was surrounded by a copper vessel with a solution of copper sulfate, and all together it was packed for insulation in an earthen vessel.
Daniel’s element gave a stable voltage of 1.1 V for a long time. This, of course, is less than its modifications, which we still use.
Despite the high voltage, the galvanic cells of the past could not keep this indicator at a stable level – design imperfections interfered.
The first to improve the design was Edward Weston. Its element consisted of a positive mercury electrode in contact with monovalent mercury sulfate Hg 2 SO 4 and hydrated cadmium sulfate 3CdSO 4 * 8H 2 O. The negative electrode was cadmium amalgam, and the electrolyte was a solution of cadmium sulfate.
The element was distinguished by high stability and reproducibility of results, therefore, many elements used today were then created on its basis.
Modern lithium-ion batteries were invented in 1970 when Michael Stanley Whittingham showed the ability of titanium disulfide or molybdenum disulfide to incorporate lithium ions. Subsequently, the galvanic cell was improved and acquired an anode made of graphite and a cathode made of cobaltite.
Today, scientists are trying to replace lithium in batteries with sodium to increase capacity, and graphite with materials based on silicon and phosphorus, but so far the balance between capacity and stability has not been achieved.
In any case, galvanic cells as current sources will still be improved – the technology has not yet reached the limit. However, perhaps in the near future it will be replaced by something else.
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