On the night of 10 December 2019 in Stockholm, Sweden, the Nobel Prize in Chemistry was given ‘for the development of lithium-ion batteries’ to M. Stanley Whittingham, the first to invent a lithium-ion battery, John B. Goodenough, the first to use metal oxides as the cathodes, and Akira Yoshino, who invented carbon-based anodes that made Li-ion batteries a practical reality.
Batteries: a short history
In 1781, at the University of Bologna in Italy, Luigi Galvani noticed that frog legs occasionally twitched when they were hung from a brass hook and allowed to touch an iron trellis. So Galvani joined together a length of each metal to form a brass and iron arc that made the leg muscles contract when touched. Galvani had just unknowingly invented the first battery. Being an anatomist, he attributed the muscle contraction to ‘animal electricity’. He believed the metals merely conducted the electricity from one part of the frog to another. One of the earliest readers of his published findings in 1791, Italian chemist and physicist Alessandro Volta came to a very different conclusion. He thought the electricity came from the two metals used in the arc. This led to a bitter scientific feud but also to the invention of the Voltaic pile in 1799, ushering in our modern understanding of electricity.
Volta’s ‘pile’ was a stake of 45 copper discs and 45 zinc discs separated by brine-soaked paper. Each cell is capable of 0.8–1.1 V so this pile would have been capable of generating about 40 V. News of this pile came to Britain in the form of a letter to the President of the Royal Society, Sir Joseph Banks, in March 1800. In his excitement, Banks leaked the letter to several close colleagues, including surgeon Anthony Carlisle and chemists William Nicholson and Humphry Davy, well before the letter was read to the Royal Society in September. This allowed Carlisle and Nicholson to publish the discovery of electrolysis in July 1800, using Volta’s pile. Humphry Davy showed that the electricity came from a chemical reaction, not by the voltage difference between the two metals as believed by Volta.
Zn → Zn2+ + 2e–
CuO + H2O + 2e– → Cu + 2OH–
2H2O + 2e– → H2 + 2OH–
In a macabre twist, Galvani’s nephew Giovanni Aldini, while a staunch partisan of ‘animal electricity’, did not ignore Volta’s pile. Aldini used it to tour the capitals of Europe – his most famous exhibition took place in 1803 at the Newgate Prison in London, UK. He inserted metal rods into the mouth and ear of the corpse of recently executed murderer George Foster and used Volta’s pile to animate Foster. According to the official description:
On the first application of the process to the face, the jaws of the deceased criminal began to quiver, and the adjoining muscles were horribly contorted, and one eye was actually opened. In the subsequent part of the process the right hand was raised and clenched, and the legs and thighs were set in motion.
Not surprisingly, some observers thought Aldini was bringing Foster back to life. Mary Shelley knew all about Galvani, Volta and Aldini from Humphry Davy and William Nicholson, who were friends of her father, and she attended many of Davy’s public lectures. In 1816, during a cold and wet summer in Geneva with Lord Byron and her husband to be, Percy Shelley, she wrote the novel Frankenstein.
From the chemistry of Volta’s pile came the lead–acid (sulfuric acid) battery in 1854 (Wilhelm J. Sinsteden), demonstrated by Gaston Planté in 1859:
Pb + HSO4− → PbSO4 + H+ + 2e−
PbO2 + HSO4− + 3H+ + 2e− → PbSO4 + 2H2O
This reaction can produce 2.0–2.1 V. Six cells are combined in series to produce the magic 12 V required for a modern car battery. Their high peak currents compensate for their low weight-to-charge ratio so they are still the battery of choice to power vehicles. Lead–acid batteries were the first secondary battery (they can be recharged). Volta’s pile, like normal disposable batteries, is described as primary. Applying a voltage to the lead–acid battery reversed the above reactions, converting PbSO4 to PbO2 at the anode and PbSO4 to Pb at the cathode.
The next great development came when Swedish chemist Waldemar Jungner invented and patented the nickel–iron (Ni–Fe) and nickel–cadmium (Ni–Cd) batteries in 1899. In 1901, Thomas Edison patented the Ni–Fe battery in the US, which resulted in a long and costly patent dispute between the two. Edison eventually won, only because he had far greater financial resources than Jungner. The Ni–Fe batteries eventually became known as Edison batteries and were touted as the preferred battery for electric cars in the early 1900s. Electric cars actually predate steam and petrol cars, being most popular between 1850 and 1910. Ni–Fe batteries are notable in their durability, able to survive continuous recycling for up to 20 years. These batteries led to the nickel–metal hydride batteries commercialised in 1989.
M. Stanley Whittingham
Whittingham was born on 22 December 1941 in Nottingham, UK. He was educated at Stamford School for boys in Lincolnshire 1951–60 and then read Chemistry at Oxford (BA 1964, MA 1967 and DPhil 1968). After completing his DPhil with P.G. Dickens (tungsten bronzes), Whittingham went to Stanford as a postdoc, working for Robert Huggins, who introduced him to solid state ionic phenomena. Specifically, he studied the transportation of sodium (Na+) and silver (Ag+) ions in solid electrolytes (intercalation) with a view to producing superconducting materials. This research would set the stage for his discovery of the Li-ion battery.
By 1969, US production of oil could not keep pace with demand and the US (like the rest of the world) became dependent on cheap oil from the Middle East. Large oil companies such as Exxon were keen to diversify, predicting the 1973 oil crisis, and set up research facilities such as the Exxon Research and Engineering Company in Clinton, New Jersey, to which Whittingham was recruited in 1972. His mandate was to work on anything as long as it had nothing to do with petroleum. His research on tantalum disulfide (TaS2) superconductors did not go well but he did notice that the conductivity of TaS2 changed when potassium ions (K+) were intercalated. Upon further investigation, he found that the material was surprisingly energy rich and he could easily measure a 2 V potential – as good as a lead–acid battery. This called for a change of tack and he started investigating these materials for energy storage purposes.
He changed the cathode from TaS2 to titanium disulfide (TiS2) and replaced K+ with Li+ and produced the first rechargeable Li battery. The choice of Li was no accident – a quick look at the SI Chemical Data book reveals Li has the highest standard electrode potential (–3.04 V) of any metal and is the lightest (ρ = 0.534 g/cm3). Whittingham’s design was thus a Li metal anode that would give up an electron and migrate to the cathode as Li+, being intercalated into the TiS2. Upon recharging, the Li+ would migrate back to the Li cathode.
Whittingham took his invention to Exxon Headquarters in New York city; after a 15-minute meeting, the top brass decided they could commercialise this new battery. But everything was to be done in total secrecy in case their competitors in the nearby Bell Laboratories should get wind of this invention. Production had its setbacks, all to do with Li’s other unique properties. Li is highly reactive and can burn when it comes into contact with water or air. It can even burn in the absence of oxygen. This led to several Li fires at the Exxon labs. But worse was yet to come. Repeated charging and discharging cycles of the early Li+ ion batteries resulted in the Li+ ions returning to the cathode, not as a flat plate but as dendrites, whiskers of pure Li metal that could pierce the barrier between anode and cathode and short out the battery with spectacular results. To make the battery safer, Li was replaced by a LiAl alloy but this reduced the number of cycles the battery could achieve from thousands to tens.
Nonetheless, the battery was announced to the world in 1976 and plans were underway to scale the battery to eventually power a car. Unfortunately, the price of oil dived in the early 1980s and Exxon discontinued Whittingham’s battery research.
After 16 years at Exxon, Whittingham became a manager at Schlumberger-Doll Research, an oilfield services company that had an interest in electronics and semiconductors. However, he stayed there for only four years before becoming an academic at the State University of New York at Binghamton in 1988, where he remains a distinguished professor of chemistry and materials science and engineering.
John B. Goodenough
John Goodenough was born in Jena, Germany, to American parents. His parents’ relationship was ‘a disaster’. At 12, he was sent to a private boarding school at Groton and rarely heard from his parents again. He struggled with dyslexia and could not read, but he was good at maths and won a place, and an aid package, to attend Yale. He went on to graduate summa cum laude in mathematics in 1943 and was promptly conscripted to World War II.
After the war, Goodenough, then an army captain in the meteorological service posted in the Azores, received a telex ordering him to Washington, DC. Some unspent GI Bill budget money was to be used to put 21 returning army officers through PhDs in physics. Goodenough had taken almost no science as an undergrad but for reasons unknown a Yale maths professor added his name to the list. He soon found himself at the University of Chicago where he studied under some of the leading physicists of the era, including Edward Teller and Enrico Fermi. He finished his PhD (under Clarence Zener) in 1952, and went to work at MIT’s Lincoln Laboratory, joining a team that was working on a new system of computer memory.
In the mid-1950s, Goodenough and Junjiro Kanamori developed the empirical Goodenough–Kanamori rules, which rationalised the magnetic properties of metal oxides that would become important in the development of modern random access memory (RAM). By the mid-1970s, Goodenough became obsessed with finding a solution to the energy crisis that had spurred Whittingham to explore battery development, but this could not be done at the Lincoln Laboratories because they were funded by the air force and energy was the responsibility of the National Labs.
In 1976, Goodenough applied for a position as professor of the Inorganic Chemistry Lab at Oxford and was surprised to be selected, considering he had virtually no chemistry background. In that same year, Exxon unveiled the Li-ion battery, which was briefly commercialised by Exxon before the aforementioned tendency for these batteries to explode and catch fire became apparent. Goodenough thought he could create a more powerful battery than Whittingham’s by replacing the TiS2 with a metal oxide, with which he was very familiar from his days at MIT. Goodenough asked two postdocs to systematically work through all the metal oxides to see which ones could accommodate the most Li+ ions that could be pulled out by applying a potential of 4 V. The answer came back as cobalt oxide (CoO2). The new battery was completed in 1980, using lithium tetrafluoroborate in propylene carbonate as the electrolyte and Li metal or Li0.1V2O5 as the anode. The discovery of CoO2 cathodes allowed the use of anodes of much higher potential than Li metal but these proved more difficult to find. Interestingly, Oxford declined to patent the new battery, which is too bad because it turned into a multibillion-dollar-a-year business.
In 1986, Goodenough hit the English mandatory retirement age of 65 and left Oxford to join the University of Texas at Austin in the Cockrell School of Engineering departments of Mechanical Engineering and Electrical Engineering. There he has continued his research on ionic conducting solids and electrochemical devices and at the age of 97 still feels he has one more big breakthrough in him.
The final breakthrough for the 2019 Nobel Prize came in 1985 from Japan. In the West, the low cost of petroleum products in the 1980s put an end to battery research. However, in Japan electronics companies were very motivated to find light and powerful batteries to power their new mobile devices (mostly radios, cordless telephones and cameras).
Akira Yoshino was born in Osaka, Japan, in 1948. He went to Kitano High School, a European-style school founded in 1873. He then earned his BSc (1970) and MSc (1972) in Chemistry from Kyoto University and went to work for Asahi Kasei Corporation. He started working on polyacetylenes – they had recently been reported as organic conductors by Hideki Shirakawa (Nobel Prize, 2000) and there was a lot of interest in using these molecules in microelectronics. In 1981, Yoshino began to investigate rechargeable batteries made from polyacetylene to avoid the dangers of solid Li metal anodes of Whittingham’s battery but was unable to find a suitable cathode. In1983, he read about Goodenough’s CoO2 anode and paired this with his polyacetylene anode to produce his first working battery. Other carbonaceous materials were tried and eventually, and somewhat ironically, petroleum coke was found to make the best anode. A prototype was finished in 1986.
This marks a new concept in Li-ion batteries, based on the transfer of Li+ ions rather than the conversion of Li+ to Li metal. The Yoshino battery was the first Li+ ion battery that contained no metallic lithium. The battery was lightweight, developed more than 4 V and, most importantly, was safe and could be punctured without catching fire. Another safety feature was that if the battery overheats, as in the case of a short circuit, the barrier between anode and cathode melts, closing off the pores to prevent rapid discharge. The official launch of the new battery was in 1991 and championed by Sony; however, it did not really catch on until 1996 and the advent of laptop computers.
Today, an electric car can outrun a Bugatti Veyron (16-cylinder quad turbo) in a standing quarter-mile and electric trucks and mining machinery are already in production, with companies such as Renault, Volvo and MAN leading the way. However, the real driving force behind an electric vehicle revolution will be AI and self-driving technologies. This will change the car from a transportation method to a social space where all occupants can consume media, correspond, work and socialise. Na-ion batteries are under development and already display some unique advantages over Li-ion batteries such as a wider range of operating temperatures and lower costs.Energy storage is also essential for transforming energy production to a decentralised, carbon-free system, where energy can be produced from renewable sources and stored in high power density batteries, thereby lessening the impact of climate change.