In the early 1980s, a lithium battery researcher at Exxon watched his work get shelved because the price of oil collapsed. A few years later, a chemist at a Japanese company dropped a heavy piece of iron on a prototype in a test facility built for explosives. Nothing happened. Akira Yoshino later called that moment “the moment when the lithium-ion battery was born.”
Between those two scenes sits the story the Royal Swedish Academy of Sciences told when it gave the 2019 Nobel Prize in Chemistry to John B. Goodenough, M. Stanley Whittingham and Akira Yoshino.
Whittingham and the first lithium battery
Lithium was purified in 1817 by Swedish chemists Johan August Arfwedson and Jöns Jacob Berzelius. It is the lightest solid element, and it gives up its outer electron more readily than almost anything else, which makes it ideal for a battery. It is also unstable. Pure lithium has to be stored in oil.
Whittingham joined Exxon in 1972. The oil company was diversifying, worried that petroleum was finite, and gave top energy researchers wide freedom as long as they stayed away from oil. Working with materials that can hold ions in tiny spaces, Whittingham found that one compound had a very high energy density, measuring a couple of volts. He swapped heavy tantalum for lighter titanium and used lithium as the negative electrode. The result was a rechargeable battery that worked at room temperature.
It had a nasty flaw. With repeated charging, thin whiskers of lithium grew and reached the other electrode, causing short circuits and sometimes fires. According to the Academy, the fire brigade was called out several times and threatened to bill the laboratory for the chemicals used to put out lithium fires. Whittingham announced the battery in 1976, and a Swiss clockmaker used it in solar-powered watches. Then oil prices fell in the early 1980s, Exxon cut back and the technology was licensed to three companies.
Goodenough doubles the voltage
Goodenough, then a professor at Oxford, reasoned that a metal oxide would beat Whittingham’s metal sulphide in the positive electrode. His group’s search turned up lithium cobalt oxide. Whittingham’s battery gave more than two volts, while Goodenough’s reached four. He also realized that a battery did not have to be built in its charged state. In 1980 he published the finding.
Yoshino makes it safe and sells it
Western interest in alternative energy faded as oil got cheaper. Japanese electronics makers, hungry for lightweight rechargeable batteries for video cameras, cordless phones and computers, kept going. Yoshino, at Asahi Kasei, paired Goodenough’s cathode with petroleum coke, a by-product of the oil industry, for the negative electrode. The cell was stable, light and delivered four volts. Because the lithium ions move between the electrodes without damaging them, it could be charged hundreds of times, and it contained no pure lithium.
In 1991, a major Japanese electronics company began selling the first lithium-ion batteries. Eyerys credits Asahi Kasei with developing the technology and Sony with commercializing it, with a joint company of Toshiba Battery and Asahi Kasei following in 1992. Mobile phones shrank, computers became portable, and MP3 players and tablets appeared.
The cells have limits. Eyerys notes that they are more fragile than nickel-cadmium types, contain a flammable electrolyte and need protection circuits. The Academy adds that no one has yet found something that beats lithium-ion capacity and voltage, though Goodenough later replaced the cobalt oxide with iron phosphate, a more environmentally friendly choice. The Academy described the battery as making a fossil-fuel-free society possible, from electric cars to storing solar and wind power.
Sources
- Asahi Kasei And Sony Commercialized The First Lithium-Ion Battery | Eyerys
- The Nobel Prize in Chemistry 2019 – Popular information – NobelPrize.org (Royal Swedish Academy of Sciences)
