Birth of the Fuel Cell

Abstract

This is the first written positive identification of the fuel cell effect.

1.1 January 1839

“… we are entitled to assert that the current in question is caused by the combination of hydrogen with (the) oxygen (contained dissolved in water) and not by contact”.

This is the first written positive identification of the fuel cell effect. It is the final conclusion of the paper “On the Voltaic Polarization of certain Solid and Fluid Substances” [1] by Christian Friedrich Schoenbein (spelled “Schönbein” in German), Professor of Physics and Chemistry at the University of Basel in Switzerland. The account appeared on page 43 of the January 1839 issue of “The London, Edinburgh, and Dublin Philosophical Magazine”, in short, “Philosophical Magazine” or “Phil. Mag.”.

Photo: Foto-Atelier Braun, Metzingen (Naturhistorisches Museum Basel)

Christian Friedrich Schoenbein (October 18, 1799–August 29, 1868).

William R. Grove must have read this publication, because he added a short postscript, dated “Jan. 1839”, to a paper on a different subject that he had written and most likely also submitted to the editor in December 1838. In his one-page note, he reported that a voltage had been observed in his laboratory during the combination of hydrogen and oxygen in a galvanic cell by the use of platinum electrodes. Grove's account “On Voltaic Series and the Combination of Gases by Platinum” [2] appeared on page 129 of the February 1839 issue of the Philosophical Magazine. It ends with the visionary remark: “I hope, by repeating this experiment in series, to effect decomposition of water by means of its composition”. That is, Grove implies that he can produce electricity by combining the constituents of water—hydrogen and oxygen—and use this electricity to convert water back into hydrogen and oxygen by electrolysis.

Photo: The Bridgeman Art Library, London (The Royal Institution, London)

Sir William Robert Grove (July 11, 1811–August 1, 1896).

Grove's paper appeared one month after Schoenbein's disclosure. Therefore, the credit of discovery of the fuel cell effect on the basis of the publication date goes to Schoenbein. But Schoenbein was not only first to publish, he was with almost absolute surety the first to accurately describe and document the fuel cell effect. Nevertheless, with his brilliant and ingenious later research and development of the gas battery, Grove established himself as the inventor of the fuel cell generator and the founder of the fuel cell technology. His work is documented in his reports of 1842 “On a Gaseous Voltaic Battery” [3], in “On the Gas Voltaic Battery—Experiments made with a view of ascertaining the rationale of its action and its application to Eudiometry” [4] in 1843, and “On the Gas Voltaic Battery—Voltaic Action of Phosphorous, Sulphur and Hydrocarbons” [5] in 1845. Grove combined his innovative ideas with existing fundamental scientific know-how to create a new technology of practical nature.

Grove's ingenious invention of 1845 soon became a sleeping beauty, revived by the manned space program in the 1960s. During the following 60 years neither Grove’s contributions to the birth of the fuel cell have been fully uncovered, nor has the role of Schoenbein and others been properly acknowledged. This text may shed some light on the early years of science when electrochemistry began to grow from the Volta pile (1799) to a recognized discipline.

In the summer of 1839, Schoenbein attended the annual meeting of the Royal Society at Birmingham to present the invited lecture “Notices of new Electro-chemical researches” [6] and to receive a grant of 40 Pounds. At Birmingham he met Grove. The two gentlemen established a life-long friendship and exchanged many letters. The complete correspondence between Christian Friedrich Schoenbein and William Robert Grove has recently been transcribed. It is added to this text. For the first time, one can participate in the exchange between the two outstanding scientists of the past century who together should be credited with the creation of the fuel cell.

1.2 Dawning of Science

When the fuel cell effect was discovered scientific disciplines were based on observations, hypotheses, and speculations, all flourishing under the umbrella of “natural philosophy”. The leading figures dealt with geology, biology, physics, chemistry, medicine, pharmacy, meteorology, and many other areas. They called themselves “philosophers” and some preferred speculative reasoning to experimental proof. But most of them were active in more than one area, but are remembered today for just one of their many talents.

Science by itself could not provide a living, but a proper profession did. Who would associate the painter Leonard da Vinci with ingenious engineering, the poet Wolfgang von Goethe with hydrogen experiments or the theory of colors, the engraver Albrecht Dürer with the architecture of the fortress of Schaffhausen, or the U.S. statesman Benjamin Franklin with the invention of the lightning rod? The keen minds of those days were active on all frontiers of knowledge. Thinkers became “Nature Philosophers”, and therefore later scientists and science was considered a part of philosophy. This tradition is still alive. Universities award the “Doctor of Philosophy” or Ph.D. for outstanding accomplishments in sciences.

At the time of Schoenbein and Grove, physical matter was still assumed to be an amorphous conglomeration of one or more chemical compounds, a pudding or dough of substance. The concept of discrete molecules, atoms, electrons, ions, or electric charges had not yet been proposed. Distinction was made between elements and molecules, the first being the pure substance, the latter the smallest identifiable body thereof. Today, one differentiates between atoms and molecules, but then no distinction was made between the two.

Also, there was no general understanding of electricity. Voltage, current, and power had not yet been sorted conceptionally, although Ohm's law (for given electric current the voltage drop across a resistor is proportional to the resistance) had already been proposed. Electricity was assumed to be an invisible substance flowing through conductors. Its strength was measured by the length of an arc, the amount of gas liberated by electrolysis, or by the number of persons feeling the sensation of an electric shock when holding hands.

One spoke of an “electric forces”, but observed voltage, current, charge, or power. One even distinguished between chemical, frictional, meteorological, or magnetic electricity. In 1838 [7] Schoenbein argued: Although we do not yet understand its nature, there is only one kind of electricity, a particular state of motion of carriers of the current phenomenon. The motion of this carrier can be caused by a number of means. If magnetism and chemistry can under certain circumstances produce heat and light, why should they not also make electric currents flow? By analogy, there are many means to set bodies into sounding motion, even by magnetism as recently shown.

Also, the instruments for electrical experiments were at an early stage. Simple electrolyzers, called “Voltameters” (today spelled with two “m”) in honor of Alessandro Volta, were used to measure the product of current and time, i.e., electric charges. A sketch of such instrument and its connection to a battery can be found in Grove's paper “Experiments on Voltaic Reaction” [8] of 1843.

Schematic drawing of a “Voltameter” (right) connected to a Grove Cell (left). From Grove's paper of 1843 [8]. A sketch of the arrangement can also be found in Grove's letter to Schoenbein of November 14, 1843 [9]

Simple galvanometers (invented by Luigi Galvani) had found their way to laboratories. However, one was not yet aware that the measurements were affected by the low coil resistance of the instruments. Therefore, current measurements were distorted by the applied voltage or voltage readings by the current flow. Schoenbein was fortunate. In 1838, he received one of the most sensitive galvanometers of his time. With 2000 windings on the coil the internal resistance of the instrument was sufficiently high for sensitive voltage readings. 200 windings per coil were standard in those days.

Other instruments or machines of scientific interest were electric motors, induction coils, or Morse apparatuses. From Schoenbein's laboratory in Basel, a few of such items have been preserved. They are presented here to illustrate the state of the art of 1840. Incidentally, some, perhaps all of the devices shown were built by Francis Watkins of London. Schoenbein purchased the induction coil and the electric motor from Watkins on his visit to London in 1839.

Photo: AKS Metzingen (Historisches Museum Basel)

Galvanometer with 2000 windings used by Schoenbein for his polarization experiments (the string-suspended magnet is missing).

Photo: AKS Metzingen (Historisches Museum Basel)

Electric motor bought by Schoenbein in 1839 from Watkins and Hill in London.

Photo: AKS Metzingen (Historisches Museum Basel)

Induction apparatus bought by Schoenbein in 1839 from Watkins and Hill in London.

Photo: AKS Metzingen (Historisches Museum Basel)

Morse apparatus bought by Schoenbein in 1851.

Chemical laboratories in general looked more like a distillery than anything else. Charcoal fires or spirit lamps provided the heat. Until 1849 Schoenbein used the washroom in the basement of the “Falkensteiner Hof”, a historic building still standing in Basle for his chemical and electrochemical research. There he discovered the fuel cell effect, isolated ozone, and invented gun cotton. His laboratory must have looked similar to that of Michael Faraday whose work environment is depicted below.

Photo: AKG Berlin (The Royal Institution, London)

Faraday in his laboratory.

1.3 Early Days of Electrochemistry

A short review of the early days of chemistry may help to illuminate the process of intellectual and experimental development of fuel cells. Three independent discoveries had to be merged before electric currents from the chemical reaction of hydrogen and oxygen could be drawn from the electrodes: chemistry, electrochemistry, and catalysis. The understanding that water is formed by a combination of hydrogen and oxygen was necessary, but not sufficient to explain the process. The chemistry had to take place under galvanic conditions (with an electric current flowing) and the presence of platinum was mandatory.

Around 1835 hydrogen and oxygen had become laboratory gases. The English chemist Henry Cavendish had discovered hydrogen in 1766. It was generated by various chemical reactions, preferably by dissolving metals in acids. In 1783, the first hydrogen balloons were flown in Paris.

Photo: AKG Berlin (Aquatint by C. Rosenberg)

Henry Cavendish (October 10, 1731–February 24, 1810).

Oxygen was isolated in 1771 in Germany by Carl Wilhelm Scheele. But there are other names associated with the discovery of oxygen: Lavoisier in France and Priestley in England. Apparently, the time was then ripe for the isolation of oxygen. From then on the gas was produced in larger quantities by an increasing number of chemical processes.

Photo: AKG Berlin (woodcut by Ida Amanda Maria Falander)

Carl Wilhelm Scheele (December 9, 1742–May 21, 1786).

Soon it was established that water was obtained by oxidation of hydrogen. In 1806 Humphry Davy, another Englishman, was able to split water into its two constituents by electrolysis. He also established the stoichiometric ratio of 2:1 for the two gaseous constituents of water. By 1838 the chemistry of water formation was sufficiently well understood.

Photo: AKG Berlin (copperplate engraving by Warthington)

Sir Humphry Davy (December 17, 1778–May 29, 1829).

Alessandro Volta of Pavia provided the second fuel cell ingredient: “electrochemistry”. In 1799, he built and operated the first electrochemical element consisting of zinc and copper disks alternatively stacked with felt patches soaked with diluted sulfuric acid between them.

The “Volta Pile” was certainly one of the key inventions of science. It allowed generating strong electric currents not only for experiments in physics and chemistry, but also for practical use. Davy's electrolysis of water and isolation of potassium and sodium became possible with Volta's invention.

Photo: AKG Berlin (woodcut)

Alessandro Volta with his “Volta Pile” (February 18, 1745–March 5, 1827).

Currents generated by friction are much too weak to affect decomposition of water. Other materials were brought in galvanic contact to generate electricity. Also, soon after Volta's discovery the German Johann Wilhelm Ritter, Professor in Jena and Munich, built the first reversible electrochemical element, then called “charging pile”, but now better known as an accumulator. There is some indication that he may have been the first to observe voltage when hydrogen and oxygen were in galvanic contact with platinum electrodes.

Photo: Deutsches Museum München (woodcut)

Johann Wilhelm Ritter (December 16, 1776–January 23, 1810).

A few years later, in 1826, Georg Simon Ohm at Würzburg (Germany) found the relationship between voltage, current, and resistance.

Photo: AKG Berlin (painter unknown)

Georg Simon Ohm (March 16, 1789–July 6, 1854).

In 1820, Michael Faraday (London) gave a first quantitative description of electrochemical reactions. Many laws of electricity and many basic inventions emerged in the 30s of the nineteenth century: induction laws (Faraday 1831), dynamo (Pixii, 1832), laws of electrolysis (Faraday, 1834), and the telegraph (Morse, 1837), to name a few. Electricity was the key subject of research of philosophers who at that time had not yet been assorted into physicists, chemists, and electrochemists and alike.

Photo: AKG Berlin (painting)

Michael Faraday (September 22, 1891–August 25, 1867).

The third contribution to the understanding of fuel cells came from catalysis. In the early 1800s, platinum came to Europe from South America. The chemical properties of this noble and precious metal were soon recognized. In 1826, Wolfgang Döbereiner discovered the catalytic properties of platinum. He demonstrated the ignition of hydrogen at room temperature in the presence of the noble metal. He designed a practical lighter, which was in widespread use. The “Döbereiner Feuerzeug” produced a flame by passing chemically generated hydrogen over a strip of platinum metal. But in 1838 only a few researchers used platinum in their electrochemical experiments and were, therefore, in a position to discover the fuel cell effect.

1.4 The “Platinum Laboratories”

1.4.1 William Robert Grove

In 1838, William R. Grove was working on the development of the “Grove Cell”, a powerful platinum-zinc battery. The two electrodes were placed in different compartments of the device. The platinum cathode and the zinc anode were in contact with diluted nitric acid and sulfuric acid, respectively. Ion exchange between the two chambers was enabled by a porous clay diaphragm [10, 11]. The electromotive force of a “Grove Cell” was remarkable for those days: 1.8–2 V.

Foto: Deutsches Museum München (Deutsches Museum München)

A cut-away presentation of a “Grove Cell” built by Watkins in London according to specifications of Grove and Schoenbein.

Grove certainly had platinum in his laboratory, but he was hardly interested to use this precious metal for basic scientific research. To Grove, platinum was electrode material for powerful galvanic elements, not a catalyst for chemical combinations.

Grove's work is reflected by his publications between 1836 and 1842. Before and after his paper “On Voltaic Series and the Combination of Gases by Platinum” [2]. Grove was fully absorbed by work on voltaic series. Grove experimented with the parallel and series connection of voltaic elements. Also, he developed powerful batteries.

This is evidenced by his publications between 1839 and 1842: “On a new Voltaic Combination” [12]; “On Voltaic Series (and the combination of Gases by Platinum)” [2]; “On the Interaction of Amalgamated Zinc in acidulated Water” [13]; “On a small Voltaic Battery of great energy; some Observations on Voltaic Combinations and forms of Arrangements: and on the Inactivity of a Copper positive Electrode in Nitro-Sulphuric Acid” [10]; “Report on a presentation of different batteries” [14]; “On some Phenomena of the Voltaic disruptive Discharge” [15]; “On some Electro-Nitrogurets” [16]; and “On a Voltaic Process for Etching Daguerreotype Plates” [17].

In those years, Grove focused his attention on the development of electrochemical systems. He was not so much concerned with fundamentals or scientific discoveries, but devoted much of his precious time to engineering work. Grove was a practicing lawyer.

When Grove returned to fuel cells in 1842, he did it again in the style of an inventor. He had learned to increase the power of voltaic arrangements by connecting elements in series. In his famous paper of 1842 “On a Gaseous Voltaic Battery” [3, 18], he not only describes the design of a single cell, but presents the results obtained with a powerful stack of 50 fuel cells connected in series. Also, the beautiful illustration in [3] has become the “trademark” of fuel cell activities worldwide. With this work Grove assumes the role of the leading innovator of fuel cell technology.

A year later he published a most comprehensive paper [4] and a second one in 1845 [5]. Both papers also appeared in many versions, including English [19,20,21], French [22], German [23,24,25], and perhaps some other languages. The combined paper reads like the text for a patent application or a textbook on fuel cells. There is much more substance in these publications than in the first account of 1842 [3] which is frequently referenced. Also, the second series of papers is illustrated with beautiful pictures, the most revealing one being reproduced on the cover of this book.

One mystery remains. The title of Grove's 1839 paper on the subject [2] is composed of two parts, “On Voltaic Series” being the first and “the combination of Gases by Platinum” the second. The first part properly captures the type of work Grove was then involved in, but the second part marks a singular point in Grove's battery development activities. There is no doubt that he could have accidentally observed the fuel cell effect, because at that time he was working with platinum to develop his platinum-zinc “Grove Cell”. But in his short postscript of January 1839, he presents so little evidence that one is inclined to assume that no serious electrochemical experiments on the combination of hydrogen and oxygen in the presence of platinum had ever been performed in Grove's laboratory before January 1839—and that during that month only hasty observations had been made.

Is it possible that Grove, after reading Schoenbein's paper of January 1839, quickly verified the results of his Swiss colleague with a primitive experimental set-up of his own? Without making reference to Schoenbein (making reference to fellow scientists was not ethical standard in those days), Grove verified some essentials of Schoenbein's report: platinum is needed; no effect is observed when anode and cathode are exposed to identical gases; positive polarity for hydrogen, negative for oxygen; the effect decays unless the electrodes are frequently wetted by exposure to gas; etc.

Furthermore, Grove's experiments must have lasted for at least 24 h. He appears to have experimented with a primitive fuel cell, but to what extent? Also, there is no sign that he did this work before and independently of Schoenbein. The total absence of related activities before and after his publication of February 1839, the bifurcated title, and the two different dates in his publication suggest that Grove may have verified Schoenbein's results in his laboratory in January 1839. He was in a position to do so, because he had all three ingredients at hand: water chemistry, experience with galvanic systems and platinum.

It is also of interest to note that only the second part of Grove's paper [2] was presented later to the international scientific community. The French account “Combinaison des gaz par le platine” [26], a report by Antoine César Becquerel (grandfather of the discoverer of radioactivity Antoine Henri Becquerel) to the French Academy of Science [27] or the German presentation “Zersetzung und Rückbildung von Wasser durch eine einfache Platinkette” [28] dealt only with the second part of Grove's original twin paper [2]. The first part of the paper was never mentioned in any of the international journals.

1.4.2 Christian Friedrich Schoenbein

During his first years as a scientist, Christian Friedrich Schoenbein was most interested in the origin of voltaic electricity and the chemical interaction at the interfaces between electrodes and electrolyte. Today he is remembered for his discovery of ozone and for his invention of gun cotton and some other substances. But Schoenbein's contributions to the advancement of science reach far beyond those two cornerstones.

Schoenbein bridged the alchemistic past with the scientific future of chemistry. Among his colleagues, he was highly respected because of his visionary ideas and his kind personality. Michael Faraday, with whom Schoenbein exchanged almost 130 letters in 26 years [29], called him his best personal friend. Both were of approximately the same age (Faraday 1791–1867, Schoenbein 1799–1868). Both were of humble origin (Faraday's father a blacksmith, Schoenbein's father a dyer). Both rose to fame without any formal education. Schoenbein became a professor, although he had never taken an academic examination. Some of the letters of Schoenbein or Faraday contain interesting clues about the discovery of the fuel cell effect.

On the occasion of Schoenbein's recent 200th birthday, Peter Nolte presented a modern biography [30] of the chemist. The German text informs about the following. Born and raised in Metzingen (Germany), Schoenbein moved around in Europe in search of knowledge and experience—2 years in Erlangen (Bavaria), 1 year in Keilhau (Thuringia), 3 years in London, 1 year in Paris—before he was called to Basel in 1828. It took him some years to start his scientific career. But his first paper in 1836 already dealt with the chemical origin of galvanic electricity: “Neuer Beweis für den chemischen Ursprung der voltaischen Elektricität” [31] or the French version “Nouvelle preuve de l'origine chimique de l'ectricité voltaïque” [32].

At that time scientific papers were not just published once, but simultaneously in the leading scientific journals of Europe. Schoenbein's work of 350 original papers is contained in about 1300 publications in four languages. Unfortunately, not all of his work is presented in English language, but the articles cited document Schoenbein's involvement with the chemistry of galvanism.

Photography of a daguerreotype taken before 1849. Universitätsbibliothek Basel

Christian Friedrich Schoenbein (right) with Wilhelm von Planck (left) and Friedrich Miescher (top).

Proof for this is the series of papers published in the Philosophical Magazine: “Further Experiments on a peculiar Voltaic Condition of Iron” [33, 1837], “On the mutual Voltaic Relations of certain peroxides, Platina and inactive Iron” [34, 1838]; “Further Experiments on the Current Electricity excited by Chemical Tendencies, independent of ordinary Chemical Action” [35, 1838]; and “Discussion of M. Fechtner's Views of the Theory of Galvanism, with reference, particularly, to a circuit including two Electrolytes, and to the relations of Inactive Iron” [36, 1838]. Further: “On the Voltaic Polarization of certain Solid and Fluid Substances” [1, 1839], and “Notice on some peculiar Voltaic Arrangements” [37, 1839].

For the same time period, one can cite over 30 publications in German and French [1, 7, 38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60] on studies of polarization, galvanism, action of platinum (then called “platina”), and other issues related to or leading to the discovery of the fuel cell effect. Schoenbein systematically explored the scientific base of the interaction between gases, electrolyte and electrode materials. Many of these papers contain information on secondary currents observed for reaction partners other than the familiar hydrogen-oxygen-platinum combination.

Of historic interest is the French language publication “Phénomènes de polarisation et d'odeur causés par l'électricité ordinaire” [60] in which the results of his early fuel cell studies are related to the formation of ozone.

His announcement of the discovery of the fuel cell effect to the English-speaking scientific community [1] is a summary, not an intermediate report on his work on polarization of gases and liquids in the presence of platinum. His statements are so revealing that the essentials shall be presented here in full length in the original wording:

A platina wire polarized either in the positive or negative way loses its particular condition by being heated red-hot. ….

A platina wire positively polarized loses its peculiar condition by being plunged only for a single moment into an atmosphere of Chlorine.

A platina wire positively polarized loses likewise its electromotive power by being placed in an atmosphere of Oxygen. … but it should remain for some seconds in the gas mentioned.

A platina wire negatively polarized loses its peculiar condition by being put into an atmosphere of hydrogen, but … the wire … should remain for some seconds in the gas.

A platina wire polarized either negatively or positively is not sensibly affected by being placed in an atmosphere of carbonic acid (rem.: meaning CO₂) or in one of any other gas which does not chemically act either upon Hydrogen or Oxygen.

A platina wire … assumes in every respect the condition and voltaic bearing of a positively polarized wire by being plunged only for a few seconds into an atmosphere of Hydrogen

Gold and Silver are not sensibly affected under the same circumstances

A platina wire does not acquire any degree of electromotive power by being put into oxygen gas: the metal remains in its natural state. Neither is any degree of such power acquired by gold or silver under the same circumstances.

Platinum, gold, and silver, by being placed only for a few seconds in an atmosphere of chlorine, assume the voltaic state of a negatively polarized wire.

Water slightly acidulated with sulfuric acid and holding some hydrogen dissolved, bears to acidulated water containing no hydrogen the same voltaic relation that zinc does to copper; provided however, both fluids be separated from each other by a membrane, and connected with the galvanometer by means of platina wires. If for the latter purpose … gold or silver wires are made use of, the said fluids do not excite the least current.

The two fluid being acidulated water containing some oxygen dissolved, the other being likewise acidulated water containing no oxygen, appears to be in a voltaic point of view perfectly indifferent to each other, whether they are connected with the galvanometer by platina, silver, or gold wires.

Water slightly acidulated with sulfuric acid and holding some chlorine dissolved bears to acidulated water not containing any chlorine the same voltaic relation that copper bears to zinc. In other terms, the former fluid acts under certain circumstances the electromotive part of the peroxide of silver, lead, etc.

The aqueous solution of hydrogen mentioned in §10 loses its property to excite a current by being mixed with a certain quantity of an aqueous solution of chlorine and vice versa, the latter fluid loses its electromotive power mentioned in the §12 by being mixed with a sufficient quantity of hydrogen dissolved in water.

Muriatic acid positively polarized loses its peculiar voltaic condition by being mixed with some chlorine, and the same acid being negatively polarized loses its polarity by being treated with some hydrogen. Schoenbein then draws five conclusions:

• 1. The secondary currents produced both by polar wires, electrolytic fluids, and secondary piles are due to chemical action, i.e., (in the cases mentioned) to the union of oxygen with hydrogen or that of chlorine with hydrogen: and not as M. Peltier seems to think the mere act of the solution in water of the gases mentioned.

• 2. The chemical combination of oxygen and hydrogen in acidulated (or common) water is brought about by the presence of platina in the same manner as that metal determines the chemical union of gaseous oxygen and hydrogen.

• 3. The current produced by a platina wire being surrounded by a film of chlorine, or by water holding chlorine in solution, is not dependent on the action of the latter body upon platina, but on the action of chlorine upon the hydrogen of water.

• 4. Electrolytic bodies do not suffer even the weakest current to pass through them without undergoing decomposition.

• 5. The most delicate test to ascertain that electrolyzation has taken place is the polarized state of the electrodes.

He then interprets his findings as conclusive evidence of the correctness of the chemical theory of galvanism: “If the mere contact of the two different fluids mentioned there were the real cause of the current obtained, it is obvious that the same current ought to be produced whether the fluid be connected with the galvanometer by means of gold, or if they be connect with the instrument by that of platina wires…”

Then follows the final conclusion already stated above: “… we are entitled to assert that the current in question is caused by the combination of hydrogen with (the) oxygen (contained dissolved in water) and not by contact”.

I am, Gentlemen, yours &c. C. F. Schoenbein

Bâle, Dec. 1838

In the extensive report in German [7], also dated December 1838, Schoenbein even advanced a theory of the observed (fuel cell) effect, which comes very close to today's understanding of hydrogen fuel cells, except that he had to find a substitute for the yet unknown hydrogen ion or proton. He postulated the existence of a “hydrogen suboxide” which carries the hydrogen from the anode to the cathode where it combines with oxygen to form hydrogen oxide or water. His postulate has the form of a question: “Oder bildet sich ein uns noch unbekanntes Wasserstoffsuboxyd ……? (Or is a yet unknown hydrogen suboxide formed at the negative electrode by a combination of the nascent hydrogen with water; and has the secondary current coming from the gold or silver wire its origin in the decomposition of this hydrogen suboxide?)”

In other words, in 1838, Schoenbein had already recognized that hydrogen acts as the transport media for the electric current from anode to cathode and that the dominating fuel cell reaction takes place at the cathode where the incoming hydrogen chemically reacts with oxygen to form water. Unfortunately, based on the results of additional experiments he later advanced another theory, which was less realistic than the intuitive original explanation.

Had he been able to use hydrogen ions instead of the postulated hydrogen suboxide, Schoenbein would have correctly described the fuel cell effect in his first publications. At the beginning of 1839, Schoenbein's thorough studies had gone far beyond Grove's short engagement with the subject. But there is an indication that others may also have studied the subject.

A footnote in [53] reveals that in autumn of 1839 when visiting England Schoenbein spent time with Faraday at the Royal Institution and successfully repeated some of his polarization experiments. It must be assumed that Faraday became a late witness of Schoenbein's discoveries of 1838.

But while Grove did not add any substantial research to his first note of 1839 [2]. Schoenbein continued his studies on polarization by not only summarizing his earlier work, but by presenting new evidence on the exchange processes at the anode, the role of oxygen at the cathode, on the interpretation of the effect and on a number of related subjects [49,50,51, 61,62,63,64].

Incidentally, in his publication [49] of 1842, Schoenbein used the word “Jone” for what we now would call “ions”. There is no definition or explanation, but the word appears suddenly on only five consecutive pages of the 28 pages text. The word must have been brought to his attention when he was writing the paper, but he then returned to more familiar notations. The word “Jon” or “Jone” has not been found in any scientific writings studied for this historic review. Also, it is not known to the author who created the word. But it must be assumed that the concept of ions was established at that time.

1.4.3 Carlo Matteucci

On page 741 of the bi-weekly communication of October 10, 1838 of the French Academy of Science one can find excerpts of two letters, which the president of the French Academy of Science, Antoine César Becquerel, had received during the previous fortnight. The first one by Schoenbein is titled “Observations sur les courants secondaires” [65] (observations about secondary currents). It essentially describes Schoenbein's U-tube fuel cell experiment. Two platinum electrodes are immersed in hydrochloric acid, then an electric current is sent through the arrangement. After disconnecting the battery, a secondary current of opposite direction can be observed.

Copy: Bibliothek der Universität Basel

Carlo Matteucci (June 2, 1811–June 24, 1868).

On the same page, the conclusions of a memoir of Carlo Matteucci, Professor of Physics at Bolgona (1832), Ravenna (1838), and Pisa (1840), are communicated under the title “Sur les polarités secondaires” [66]. His results are summarized in four points. Translated into English they read:

• Platinum foils which were used to transmit the current of a battery into water and on which hydrogen and oxygen had been evolved retain a layer of gas for some time.

• Every platinum foil exposed to hydrogen gas, or oxygen gas, is covered by a layer of the gas and retains it for some time.

• When two foils, one covered with hydrogen, the other with oxygen, are immersed together in distilled water or another liquid, there is a current, which goes from the hydrogen to the oxygen in that liquid.

• A single foil prepared in one of the two gases and immersed with the other in the liquid gives rise to an electric current directed in the sense observed when both foils are used together.

Both communications essentially describe the same experiments. Is this the birth of the fuel cell? Are there two discoverers? This question remains without answer, because the answer may be hidden in Italian archives. Nevertheless, Matteucci's publication became known to Schoenbein, because it is referenced in his publication in Phil. Mag. publication of 1839 [1].

1.4.4 Jean Charles Athanase Peltier

Also, Jean Charles Athanase Peltier is mentioned in context with the observations of secondary currents. His note also appeared in Comptes Rendus, the bi-weekly journal of the French Academy of Science, but 2 weeks after the Schoenbein/Matteucci citation. Its title “Polarité secondaire des courants électriques” [67] indicates that Peltier was also exploring the origin of secondary currents. He refers to the communication of Schoenbein's results [65] in the last session of the Academy of Sciences. Peltier attributed the effect to the difference of electrode materials and considered the electrolyte to act as an electric conductor between the two metallic elements. Schoenbein later challenged Peltier's explanation of the effect.

1.4.5 Auguste de la Rive

But there may even be an earlier observation of the fuel cell effect. In his first report on the subject at the 1838 meeting of the Swiss Society of Scientists at Basel (September 12–14, 1838) “Beobachtungen über die elektrische Polarisation fester und flüssiger Leiter” [38] Schoenbein already made reference to earlier experiments by A. A. de la Rive. According to Schoenbein, the Geneva physicist had observed secondary currents already in 1827. De la Rive used platinum wires as electrodes in a galvanic system. He disconnected the primary power source and observed an electric current flowing against the original primary current. De la Rive presumes that a particular property of platinum caused this effect.

Copy: Bibliothek der Universität Basel

Auguste de la Rive (October 9, 1801–November 27, 1873).

1.4.6 Antoine César Becquerel

In the same report [38], Schoenbein also refers to the observation of secondary currents by Edmund Becquerel. The French scientist had claimed that secondary currents could only be observed for electrodes being immersed in saline solutions. The primary current would decompose the salt, the base being concentrated near the negative, and the acid near the positive electrode. According to the laws of electrochemistry, the secondary current would flow if the two electrodes had been connected by a conducting fluid. According to Edmund Becquerel, the observed effect was of chemical origin.

Apparently, both De la Rive and Edmund Becquerel had already, then, observed secondary currents. There may be others who have observed similar phenomena and reported their results before Schoenbein. But it is unlikely that a more thorough study of the fuel cell phenomenon will be raised from archives than that presented by Schoenbein in the 2 years of 1838 and 1839.

Photo: AKG Berlin (woodcut)

Antoine César Becquerel (March 17, 1788–January 18, 1878).

1.5 Discovery of the Fuel Cell Effect

Neither Schoenbein nor Grove have provided detailed sketches of their 1838/1839 experimental arrangements, but left only brief descriptions of the laboratory set-up used to perform their respective studies.

The first description of Schoenbein's apparatus can be found in a paper of 1838 dealing with the change of colors caused by heat [68, 69]. Apparently, the experimental set-up for this work was identical to the one used to study polarization effects. Two platinum electrodes were inserted into the two legs of a U-shaped glass tube. Both electrodes were connected to the sensitive galvanometer and secondary currents were observed when one leg was heated while the other remained at room temperature. He used liquids or solutions whose colors changed as a function of temperature and confirmed that the color change was associated with some voltaic activity.

The experimental system Schoenbein used for his polarization studies must have been similar, if not the same. Again, a U-tube is used. It is filled with a liquid electrolyte (diluted sulfuric or muriatic acid, acidulated water). Two platinum electrodes are placed in each leg of the U-tube.

Then the experiments were performed in three steps.

Two platinum strips depolarized by heating were inserted into both legs of the U-tube and the 2000-coil galvanometer (shown earlier in this text) was connected to both. A neutral state was verified.

Then a battery was connected to the platinum electrodes and an electric current was sent through the electrolyte. After some time, hydrogen and oxygen bubbles appeared on the positive (anode) or negative (cathode) electrode, respectively. But the appearance of bubbles was not needed to perform the experiments. Hydrogen and oxygen stayed dissolved in the electrolyte.

Then the external battery was replaced by the galvanometer. An electric current was observed whose direction was opposed to that of the original charge current. The current decayed with time, i.e., with the consumption of the accumulated gases. Also, the rate of decay must have been inversely proportional to the internal resistance of the galvanometer. Schoenbein's “sensitive” high-resistance instrument with 2000 windings was certainly better suited for this type of observation than ordinary low-resistance voltmeters with only 200 windings.

Schoenbein's U-tube experiments. Schematic based on information contained in [1]

With this simple set-up Schoenbein performed his experiments using different electrolytes, electrode, gases, etc. Again and again, he refers to the U-tube arrangement, which is described in the publications presented above.

In 1842, Schoenbein replaced the U-tube by a more sophisticated experimental set-up [57]. He used two small glass vessels separated from each other by an animal membrane. This enabled Schoenbein to separate the galvanic cell into an anode and a cathode compartment. He experimented with different electrolytes in both. But most interesting are his experiments with different electrode materials. Again, his sensitive galvanometer registered a current for platinum, but not for gold, silver, or copper electrodes.

Also, no reaction was observed when platinum was used as anode and gold as cathode material, while a heavy reaction was registered when the two metal electrodes were interchanged. By this experiment Schoenbein was able to demonstrate that the (hydrogen) fuel cell effect is essentially a cathodic reaction. Ordinary metals can be used at the anode, but platinum has to be employed at the cathode to produce a current. This is, of course, not true for the (oxygen) fuel cells MCFC and SOFC.

In 1839, he presented his work at the annual meeting of the British Association for the Advancement of Science at Birmingham [6, 45, 46]. His presentation must have been convincing, because he received a research grant [6] of £40 “For defraying the expenses of certain Experiments on the connexion between Chemical and Electrical Phenomena: the results to be reported to the Association at their next meeting” [70].

Schoenbein's procedure did not provide means for a continuous supply of pure hydrogen or oxygen to the electrodes, but both gases were generated in the second phase of the experimental procedure by electrolysis. Schoenbein had certainly noticed in 1838 that the secondary current was produced as a result of the reversal of the electrolytic separation of hydrogen and oxygen caused by the primary current, but he did not clearly state this observation in his early publication [38, 39].

Also, in his analysis [64] of Grove's important paper [3] of 1842, Schoenbein proposes the concept of the triple phase boundary. In translation: “… currents can only be generated if hydrogen, water and platinum are in contact with each other and connected in such manner that each of them forms a continuous conducting line or chain”.

Grove's experimental set-up of January 1839 is described with a few sentences [2]: “Two strips of platinum 2 inches long and three-eighths of an inches wide, standing erect at a short distance from each other, passed, hermetically sealed, through the bottom of a bell glass; the projecting ends were made to communicate with a delicate galvanometer; the glass was filled with water acidulated with sulphuric aced, and both the platina strips made the positive electrodes of a voltaic battery until perfectly clean, &c.; contact with the battery having been broken, over each piece of platinum was inverted a tube of gas, four tenth of an inch in diameter, one of oxygen, the other of hydrogen, acidulated water reaching a certain mark of the glass, so that about half of the platina was exposed to the gas, and half to the water”.

Grove's experiment of 1839 is described by the following schematic presentation:

Grove's experiment of 1839. Schematic based on information contained in [2]

The main difference to Schoenbein's experiment is the supply of hydrogen and oxygen. While Schoenbein generated the gases within the system by using a primary current for electrolysis, Grove supplied them from an external source. Initially, both electrodes were connected to the positive polarity of a voltaic battery for cleaning purpose, not for affecting polarization or electrolysis. It seems that Grove had followed the logic of Schoenbein's conclusions: If the current in question is caused by the combination of hydrogen and oxygen, why not feed these gases directly to the electrodes rather than generating unspecified amounts thereof by electrolysis. Grove provided a practical, simple engineering solution while Schoenbein remained in search of fundamental phenomena.

1.6 Schoenbein Meets Grove

After the publication of Schoenbein [1] and Grove [2] in the Philosophical Magazine of 1839 neither of the two ever mentioned the paper of the other in any of his publications of that year. The three communications of Grove's paper [26,27,28] were not more than short summaries or translations of the second part of the original publication of 1839. They contained no further evidence. Grove went on writing about his battery development.

But on the other side, Schoenbein did also not mention Grove's work, although he was generally making accurate and fair reference to work done by others. In a paper dated May 1, 1839 [40], Schoenbein reports on effects of platinum on nitric acid, methanol, and ether under the influence of electric currents. He could have added a few remarks on Grove's paper, but he did not do so. But in his subsequent publication, “Notice on some peculiar Voltaic Arrangements” in the Philosophical Magazine [37], dated July 1839, Schoenbein refers to the French report [27] on Grove's original paper [2] by Becquerel, but not to the publication in the Philosophical Magazine itself.

Perhaps Schoenbein had no immediate access to the British journal. Nevertheless, he claims his stakes: “I perceive from No. 20 of the Comptes Rendus, that Mr. W. R. Grove has made a communication to the French Academy, in which there is stated the same fact with regard to water. In giving it, as a novel one, Mr. Grove was most likely not aware of what I published six months ago in the Bibliothèque Univ. No. 35, p. 189, and in the Lond. & Edin. Phil. Mag. No 85, p. 45”. Schoenbein was then aware of Grove's publication, but there is no evidence of the reverse.

Schoenbein and Grove met for the first time in 1839. Schoenbein was the invited speaker [45] at the annual convention of the British Association for the Advancement of Science at Birmingham [6]. On his way to the meeting he spent some days in London visiting Faraday and friends from earlier stays in the capital. There are three sources of information that allow us to reconstruct much of Schoenbein's visit to London, including his meetings with Faraday and other friends, his meeting with Grove, his scientific activities in London, and his reflections on the English society. Schoenbein had previously lived in London from 1825 to 1827 and again in 1828 for some weeks:

In 1842 Schoenbein published a fascinating 480-page account of his trip to England, which is a valuable source of information in general and allows us to follow Schoenbein's activities during this and earlier visits to England [71].

The 126 letters exchanged between Schoenbein and Faraday from 1836 to 1863 contain some information regarding this visit, remarks about Grove and other scientists or personal observations of important events and developments of that time [29].

Finally, between 1839 and 1868 Schoenbein and Grove exchanged about 26 pairs of letters. These have finally been transcribed and are published for the first time in this book.

According to this communication, Schoenbein first met Grove at Birmingham. Both of them were the featured speakers: Grove because of the presentation of his latest invention, the platinum-zinc “Grove Cell”, and Schoenbein, because he was the invited guest speaker from the continent. Schoenbein reported on his polarization studies [45].

Schoenbein was fascinated by Grove and by his presentation of the powerful platinum-zinc battery [70, p. 100]. In translation: “At Birmingham he presented the most wonderful result of his investigation to the British Association by showing us a tiny platinum-zinc pile which compared to its size showed an astonishing power”.

Grove invited Schoenbein to spend a day at his home at Wandworth near London. Schoenbein accepted and met Grove's family. They discussed technical matters, experimented with the small cell and designed a bigger one. Then they took the train to London, visited the talented mechanic Francis Watkins at Charing Cross, and Schoenbein gave orders to build a battery of the improved design.

A few days later the powerful device was ready and in the presence of Schoenbein and Watkins the inventor Grove was asked to connect the battery to the electrolyzer. The results must have been breathtaking. Never before had one of the three gentlemen seen a more vivid gas formation by electrolysis. More so, the thick platinum wires “melted away like wax”. Schoenbein paid for the “Grove cell” out of his own pocket (the sum was later refunded by Peter Merian, rector of the University of Basle) and used it in his laboratory for many years [72,73,74].

Coincidentally, during his polarization studies, in particular, after the arrival of the powerful “Grove Cell” in his laboratory, Schoenbein in 1839 discovered ozone. As a young boy, he had first noticed this odor after the church in his hometown Metzingen was struck by lightning. But now the “electric smell” filled his laboratory to an extent, which did not remain unnoticed by the experimenter.

Schoenbein, the discoverer of the fuel cell effect, is also the buyer of the first “Grove Cell” and the “Grove Cell” becomes the key item in Schoenbein's discovery of ozone. It is fascinating how intertwined the scientific activities of these two gentlemen were in 1839. Also, from today's perspective, Schoenbein can be linked in two ways to present-day environmental issues: ozone has become a substance of great concern and fuel cells have the potential to reduce the generation of the harmful substance in the lower atmosphere.

Schoenbein visits Grove's laboratory at the London Institution and has perhaps had other encounters with his new friend. But there is no mention of any discussions they had on subjects related to fuel cells. This subject was extremely important to Schoenbein, but apparently not to Grove. Schoenbein must have raised the issue of polarization and current generation by combining hydrogen and oxygen with platinum. Apparently, Grove did not have much to say on the topic. This is, perhaps, another indication of Grove's coincidental encounter with the fuel cell effect at that time.

Schoenbein's first letter to Grove is dated November 21, 1839. It was written only a week after he had returned from England. Schoenbein proudly informs Grove that the Philosophical Society of Basel had elected Grove to become their Corresponding Member [2.4.1]. Grove replied soon thereafter. He referred to Schoenbein's visit in London, talked about the future and reported on experiments with a most powerful “Grove Cell” battery (38 elements in series). But again, not a single word can be found about subjects closely related to fuel cells. Grove is concerned with his platinum-zinc device and some other subjects. On the other hand, Schoenbein's scientific remarks mainly deal with ozone.

Then on May 2, 1843, Grove's famous paper “On a Gaseous Voltaic Battery” had already appeared in December 1842 in the Philosophical Magazine [3], Grove informed Schoenbein that he had written a second paper on the “gas battery”. Apparently, Grove did not seriously consider his postscript of 1839 to be his first paper on fuel cells, but started his personal fuel cell calendar in 1842. Also, at that time Grove may have sensed that he had passed Schoenbein in the fuel cell race and now could afford to let his colleague know: see what I have done! Grove had taken the lead in the innovative process of inventing a useful fuel cell generator.

1.7 Schoenbein and Faraday

Before continuing the account of the innovative process leading to Grove's invention, it is worth exploring in more detail the relationship between Schoenbein and Faraday.

During his first stay in London from 1825 to 1827, Schoenbein must have seen or even met Faraday, but without establishing a personal relationship. It is known that he visited the Royal Institution a number of times to attend lectures. Faraday may have presented some of these lectures.

After establishing his academic position at the University of Basel, Schoenbein sent his first letter [29] to Faraday on May 17, 1836. Its technical content was later published in the Philosophical Magazine of 1836 under the title “On a peculiar Voltaic Condition of Iron” [75]. The letter is signed with “I am, Sir, your most obedient servant—C. F. Schoenbein”, but no answer is received. Schoenbein had to make three more attempts before Faraday finally replies with two short but friendly letters, the first one signed “Your obliged and faithful Servant, M. Faraday”. A frequent exchange of 128 letters followed and ended 1862 by request of Faraday when he became too weak to compose meaningful language.

Faraday's final letter to Schoenbein of September 18, 1862 reflects on the deep affection Faraday felt for Schoenbein who later summarized the last note of his friend with the words: “It consisted only of a few lines, hardly written, and written with a trembling hand”.

Faraday wrote “Dear Schoenbein. Again and again I tear up my letters, for I write nonsense. I cannot spell or write a line continuously. Whether I shall recover—this confusion—do not know. I will not write any more. My love to you, ever affectionately yours—M. Faraday”. The great scientist suffered 3 more years before finally leaving this world on August 25, 1867.

This intense and intimate correspondence between the two has become a valuable source of information also with respect to the birth of the fuel cell. On September 13, 1838 [29], Schoenbein shared with Faraday the first results of his polarization studies: “Being just now occupied with drawing up for you a paper in English which is to contain a detailed account of my results, I will not enter at present into particulars and confine myself to stating the general fact, that fluid compound bodies being at the same time electrolytes are capable of assuming a peculiar state, which I term their electrical polarization; …”. In a subsequent note of October 20, 1838 [29], he describes his experiments in great length, mentions platinum, and presents the U-tube experiment and his observations of secondary currents.

1.8 Grove’s Fuel Cell Experiments of 1842

Most members of the fuel cell community have seen a reproduction of the original drawing of Grove's fuel cell array, which appeared in the December 1842 issue of the Philosophical Magazine [3]. With his paper “On a Gaseous Voltaic Battery” Grove marked the beginning of an innovative process, which he finished 2 years later with the disclosure of the fuel cell power generator—with the invention of a device that is now, after its discovery over 160 years ago, finally being brought to technical maturity.

A truncated version of the famous sketch is used as the insignia of the “Grove Fuel Cell Symposium”. But hardly ever is it reproduced in its original form. Grove presented his four-cell arrangement together with a small electrolyzer, or a Voltammeter, which used the current generated by combination of hydrogen and oxygen to split water into its chemical constituents.

Remember, in 1839 [2], Grove had stated the visionary remark: “I hope, by repeating this experiment in series, to effect decomposition of water by means of its composition”. Now he had fulfilled his promise and he proudly confessed: “In reading over my papers lately, I was struck with the above sentence. My impression was, that I had expressed a hope not very likely to be realized; but after a few days’ consideration I saw my way more clearly, and determined to try the experiment”.

Grove's experiment of 1842. Figure from Grove's publication of 1842 [3]

Grove did it the engineer's way. He had learned to connect many cells in series and knew from his various arrangements of 30 and more cells that new voltaic systems are best demonstrated by drawing sparks over recognizable distances. He had not just 4, but 50 cells made of the kind shown in the figure. They were all connected in series. Apparently, the cost of platinum was reduced by depositing the precious metal on the electrodes by galvanic means (“platina platinized by voltaic deposition from the chloride, …”). Each electrode was about one-fourth of an inch wide. Dilute sulfuric acid was used as electrolyte fluid.

Today's experimenters may feel amused by the manifestation of the power of the first fuel cell arrangement by Grove. Here are some of the effects that were recorded in 1842:

A shock was given which could be felt by five persons joining hands, and which when taken by a single person was painful.

The needle of a galvanometer was whirled around and stood at about 60°; with one person interposed in the circuit it stood at 40°, and was slightly deflected when two were interposed.

A brilliant spark visible in broad daylight was given between two charcoal points.

Iodide of potassium, hydrochloric acid, and water acidulated with sulfuric acid were severally decomposed; …

A gold leaf electroscope was notably affected.

The smell of ozone was noticed, etc.

A most significant observation appears as a side remark: “my assistant, who was unacquainted with the rationale of the battery, observed that the hydrogen was absorbed twice as fast as the oxygen”. Not the master, but the slave took note of the fundamental fuel cell stoichiometry: two H₂ + one O₂ ↔ two H₂O.

1.9 Schoenbein’s Response

Grove's original paper [3] appeared in the Philosophical Magazine in December 1842. Schoenbein's reaction was swift and supportive. The sequence of his publications can serve as an indicator of his linguistic and scientific preferences: On December 28, 1842, he had already completed an English account on Grove's “Gaseous Voltaic Battery”. The paper “On the Theory of the Gaseous Voltaic Battery” appeared in March 1843 [76] in the Philosophical Magazine. The German and French versions of this paper are dated January 1843. Both were also published in March of 1843 [64, 77]. Apparently, Schoenbein preferred to communicate in English on this subject.

All of Schoenbein's accounts of Grove's experiments have three things in common: Schoenbein's appreciation for Grove's accomplishment, some references to his own earlier work on the subject and an interpretation of Grove's observations. Here, his English praise of Grove's work: “The results obtained by that distinguished philosopher are, indeed, such as will certainly draw upon them the attention of all scientific men who occupy themselves with voltaic researches”. He then stakes his claims by making reference to his earlier work on polarization [1 and others] and mentions that he had observed and reported on similar effects earlier. He also added a cynical comment: “ … it might, perhaps, interest those English Philosophers who are not in the habit of reading German periodicals, to see in your excellent Magazine a translation of my paper, or some abstracts from it”.

For the interpretation of Grove's results, Schoenbein does not resort to his original fuel cell theory of 1839 [1], but to conclusions, which he derived from more recent observations of his own on the subject. With his two-chamber experiment [57] he had discovered that an electric current could be generated if hydrogen in solution with water is in contact with chemically pure water as long as no trace of oxygen is contained in either fluid.

Schoenbein then argues that oxygen cannot be directly involved, but that the origin of the electric current is an anodic reaction between the polarized hydrogen and the electrolyte. We now know that electrochemistry occurs on both electrodes, but with some degree of stubbornness Schoenbein insisted on his most recent findings. To demonstrate his supremacy, he adds a spicy postscript to his evaluation of Grove's publication: “P.S. Experimenters who are desirous of pursuing Mr. Grove's late researches, will find the effects of the gaseous pile greatly enhanced by making use of chlorine gas instead of oxygen; …”. In reality, Schoenbein may have realized at that time that Grove had taken over the control of the subject, but he had to stake the claim that he knew better than Grove.

Schoenbein's correspondence with Faraday offers additional clues. On April 26, 1843 [29], he questions Faraday about Grove: “What do you say about Grove's gaseous Battery? You will perceive that I published a paper on that subject in the last number of de la Rive's Archives. It seems our friend thinks the combination of isolated oxygen with isolated hydrogen to be a source of voltaic electricity. I cannot make up my mind to believe such a thing; my experiments at least do not lead to such an inference”.

Even then Schoenbein had not yet left the platform of fundamental science and therefore failed to recognize the practical applications of his discovery. But Faraday replied on May 16, 1843: “…As to Grove I do not recollect that he says isolated oxygen and hydrogen can by combining produce a current of electricity”. Apparently, at that time, not even Faraday was fully informed about Grove's work or prepared to appreciate the potentials of Grove's ingenious experiment.

In the coming year, Schoenbein investigated the role of oxygen in Grove’s gas battery. Again, a number of papers are published in different magazines [78, 79], but none in English. In translation, the titles reads “On the Voltaic Action of Oxygen in Grove's Gas Battery”. The same topic is treated 4 years later [80], but Schoenbein cannot report on experiments of his own. He used Grove's research results [4] to argue against Grove. Although some of the arguments appear to be proper, others are advanced for the sake of argument, not clarification.

Schoenbein at this point falls behind Grove in the development of a substantiated fuel cell theory. After all, fuel cell physics had become a sideline of Schoenbein's scientific work. Physics and chemistry will soon be separated at the University of Basle. Schoenbein is getting more attracted by chemistry. His final paper on electrochemistry reflects his new role in science. “Ueber die chemische Theorie der Volta'schen Säule” [81] (“On the chemical theory of the voltaic pile”) appeared in 1849.

Grove's publications of 1843 [4] and 1845 [5] were finally translated into German and appeared in Poggendorff's Annals of 1848 [23,24,25]. Schoenbein makes a final attempt to explain the role of oxygen in Grove's gas battery [80], but his comments do not put Grove's accomplishments in question. Since 1839 Schoenbein had spent most of his time on ozone and chemistry. The paper on the role of oxygen in Grove's gas battery of 1848 was his final contribution to the development of fuel cells. It reads more like a retreating battle than an advancing attack.

1.10 Grove’s Fuel Cell Generator

On May 11, 1843, at the meeting of the Royal Society Grove read the paper: “On the Gas Voltaic Battery—Experiments made with a view of ascertaining the rationale of its action and its application to Eudiometry” [82] which was then published in full length in the Philosophical Transactions of 1843 [4]. The word “eudiometry” was then used for the capture of gas for subsequent analyses. It is a remarkable publication. On 32 pages Grove describes and interprets 23 experiments. The text is illustrated by a plate of 12 wonderful drawings which shows his first and second experimental set-up, showing all essential details of the experiment and illustrating some experimental observations. The original plate is reproduced here.

A second paper appeared in 1845 [5]. In this remarkable study, Grove reports on fuel cell experiments with hydrocarbons. Again, he adds five wonderful drawings to his publication. The papers of 1843 and 1845 are combined in a German publication of 1848 [23,24,25].

The two papers of 1843 and 1845 are a most remarkable summary of Grove's systematic studies of the fuel cell phenomenon, of fuel cell experiments and possible applications of the “Gas Voltaic Battery” as a powerful source of electricity. Because of its completeness and its depth of understanding, Grove's combined publications [4, 5] could be considered the first textbook on fuel cells. With the second paper William R. Grove establishes himself as the prime innovator in the area of fuel cells.

Grove's fuel cell experiments of 1843. Figures 1–12 from Groves publication of 1843 [4]

The first paper was immediately translated into French and appeared in 1843 in the Archives de l'Électricité [22]. The 41 pages of text are supported by 1 page of fascinating figures. Because of its length the Philosophical Magazine had to publish it in installments. In 1844, the 28 pages of text, figures, tables, and results appeared in the April, May, and June issues [19,20,21]. The German version of both papers (55 pages plus 1 table of now 18 figures) was the last to be printed. It was published 1848 in a supplementary volume of Poggendorff's Annalen [23,24,25].

Most likely, this important document was also published in other languages. It was such a massive bombardment of the scientific community with fuel cell evidence that no debate, no reaction by other scientists, and no reverberation in the scientific community followed. Grove had basically said all there was to be said regarding fuel cells at that point in their development.

In this series of publications, Grove presented what may be called the first systematic fuel cell development. He describes three different types of fuel cell arrangements, each being an improvement of the previous one with respect to performance and handling. The progress is stated by “… in my original paper [3] when charged with oxygen, hydrogen and dilute sulphuric acid, I could not succeed in perceptibly decomposing water with less than twenty-six cells, yet the new arrangements, from their superiority in size and construction, were capable, when charged with the same gases and electrolyte, of decomposing water with four cells; and a single cell would decompose iodide of potassium”.

For a modern fuel cell developer, Grove's improvements appear to be insignificant, because even the third-generation devices look archaic to us. But when one generation is compared to the previous one, the significance of these first three steps of fuel cell development becomes evident. Four cells of the second generation were as powerful as 26 cells of the first. One could say Grove increased the efficiency by a factor of six. Also, Grove documented an innovative process of remarkable significance. While Grove's first two fuel cell generations are difficult to operate, the third lends itself to rapid experimentation under reproducible conditions.

In the first paper [4], Grove also refers to a letter of Schoenbein [May 5, 1843] including a note on the gas battery, which then appeared in 1843 [76]. This appears to be the only direct communication about the fuel cell between the two scientists. But Grove rejects Schoenbein's most recent postulate that the electric current is generated by the action of hydrogen with water. Grove's experiments show that oxygen is needed to operate a gas battery, but Grove fails in other respect. He claims that the oxidation reaction occurs within the electrolyte and not on the cathode itself.

With the first two generations of cells, Grove performed a series of systematic experiments. He first connected ten cells in series to a voltammeter and obtained from several experiments the following mean values: for 0.6 cubic inches of oxygen and 1.34 cubic inches of hydrogen absorbed in the gas battery 0.58 and 1.26 cubic inches of the two gases evolved from the voltammeter. The results show a remarkable degree of reversibility of the processes. Also, stoichiometry of the water reaction was demonstrated within reasonable limits.

Grove continued his systematic studies of the gas battery by performing 27 experiments with cells of the second generation; single cells; and 3, 4, 5, 10, or more cells in series; hydrogen, oxygen, nitrogen, iodine, bromine, carbon dioxide, and other gases; experiments lasting from a few hours to 36 days. He disproved the contact theory (electric currents originate by contact of different materials), established experimental routines, and perfected his system.

He was able to present the results of his experiments 28–30 in the appendix of his paper [4]. These experiments confirmed earlier observations and provided interesting results on “olefiant” gas, “protoxide” and “eutoxide” of nitrogen, ammonia, and other gases. All in all, an amazing account of careful research and development of the fuel cell.

Grove's publication of 1845 is another substantial [5] piece of work. In his final paper on the subject of the “gas battery”, Grove continued to present surprising substance and innovative engineering. Experiments 31–45 deal with solid fuels. Electricity is generated by oxidizing phosphorus, iodine, sulfur, and camphor in a galvanic environment. He fully recognized the novelty of his research “The results of the above experiments give, I believe, the first instance of the employment of a solid, insoluble non-conductor as the excitant of a continuous voltaic current, …”

Grove's fuel cell experiments of 1844/45. Figures 1 and 2 of Grove's paper of 1845 [5]

Grove then continued his studies with experiments 43–46. The solid camphor specimen is vaporized inside the anode chamber by an electric heating coil. Is this the first coal gasification—fuel cell device? But Grove pushes on. In the following experiments, liquid hydrocarbons like turpentine, cassia, alcohol, or ether are used to generate electricity. Is Grove the founder of the direct methanol technology? His studies are, if nothing else, proof of the ingenuity of this English lawyer-scientist.

Grove's vaporizer for solid materials. Figure 3 of Grove's paper of 1845 [5]

But with his experiment No. 53 Grove established his status as the inventor of the fuel cell and became father of a new power generating technology. After 6 years of work on the subject, Grove finally realized the practical potential of his gas battery to become a continuous source of electric power and to replace batteries of conventional design.

This epiphany is stated by Grove himself: “I have never thought of the gas battery as a practical means of generating voltaic power, though in consequence of my earlier researches, … I have been deemed by some to have proposed the gas battery for the same purpose; there is, however a form of gas battery which I may here describe, which, where continuous intensity or electromotive force is required, but the quantity of electricity is altogether unimportant, appears to me to offer some advantages over any form of battery hitherto constructed, and which, independently of any practical result, is, from circumstances peculiar to the gas battery, not without interest”.

He then continues with the description of his invention. It consists of a number of series-connected cells, each having a platinum-plated anode and a cathode of the same material immersed partially in “acidulated” or acidic water. While one electrode (cathode) is exposed to air, the other (anode) is surrounded by hydrogen. Hydrogen is continuously supplied to all cells. It comes from a chemical hydrogen generator. Grove used zinc with water to generate the gas.

All anodes of his device share the common source of hydrogen. The zinc and water can be replenished without interrupting the electricity generation. In some respects, Grove's design resembles modern air-breathing fuel cells, with just one difference: the acidic electrolyte is now embedded in the molecular structure of a polymer membrane.

Grove's schematic presentation of his invention of a fuel cell apparatus with continuous hydrogen supply. Figure 4 of Grove's paper of 1845 [5]

A six-cell schematic was shown to explain the principle. Grove's original fuel cell of relevance to modern technology consisted of ten cells all connected in series and receiving hydrogen from a single chemical generator. “We have now a gas battery, the terminal wires of which will give the usual voltaic effects, the atmospheric air supplying an inexhaustible source of oxygen, and the hydrogen being renewed as required by the liquid rising to touch the zinc; by supplying a fresh piece of zinc when necessary, it thus becomes a self-charging battery, which will give a continuous current; no new plates are ever needed, the electrolyte is never saturated, and requires no renewal except the trifling loss from evaporation, which indeed is lessened, if the battery be in action, by the newly composed water”.

Grove's 10 cell continuous power generator of 1844/45. Figure 5 of Grove's paper of 1845 [5]

Grove's first useful fuel cell is depicted above. It shows ten cells in two rows. The hydrogen generator is seen on the right, while the wires of the electric power load on the left (shown is a voltammeter or electrolyzer) are connected to the two terminals of the world's first fuel cell power generator with a continuous supply of hydrogen and oxygen. Grove even suggested practical applications for his continuous power source. “This battery would form an elegant substitute for the water battery; it would much exceed in intensity a similar number of series of that apparatus; it would be applicable to experiments of slow crystallization and possibly to the telegraph”.

Without the slightest doubt, this is Grove's invention of the fuel cell. Neither the short note in 1839 nor his first serious paper on the subject of 1842, but his recognition of the usefulness of the gas battery for continuous power generation, his innovative design and his proof of concept of the novel device established Grove as the inventor of the fuel cell. In the modern interpretation of patent offices, patents are issued for apparatuses or processes of practical use that are based on innovative combinations of new ideas and existing knowledge and experience. Grove had exactly done that.

After this burst of inventive power, Grove looked for engineering applications of electricity. Papers like “On the Application of Voltaic Ignition to Lightning Mines” [83], “On certain Phenomena of Voltaic Ignition and the Decomposition of Water into its constituent Gases by Heat” [84], or “On the Effect of Surrounding Media on Voltaic Ignition” [85] indicate that Grove was now concerned with the conversion of electricity into useful services.

This closer look at the birth of the fuel cell suggests that the historic truth is probably correctly reflected by the following presentation of dates and names: Christian Friedrich Schoenbein discovered the fuel cell effect in 1838 and William R. Grove invented the fuel cell in 1845. The time between 1838 and 1845 was spent by Schoenbein to study and interpret the phenomenon and by Grove to convert scientific evidence into a useful power generating technology.