The 2019 Nobel prize in Chemistry has been awarded to John Goodenough, Stanley Whittingham and Akira Yoshino for the development of lithium-ion batteries.
This year’s Nobel Prize in Chemistry goes to the pioneers of the lithium-ion battery, an invention that has become ubiquitous in the wireless electronics that power modern life: your phone, your laptop, and sometimes even your car. Lighter and more compact than the lead and nickel-cadmium batteries of yesteryear, lithium-ion batteries, with further tinkering, could provide a path to storing energy to power homes, airplanes—and even the grid. “Lithium-ion batteries have made a tremendous impact on our society
Like all liquid ion batteries, lithium-ion batteries contain two electrodes—an anode and a cathode—separated by a liquid electrolyte that allows ions to move back and forth. During discharge, stocks of lithium atoms at the anode give up electrons to generate a current for an external circuit. The resulting positively charged lithium ions flow into the electrolyte, while electrons return from their work to the cathode, where they are soaked up, typically by metal oxide materials. The lithium ions sidle up to the metal atoms at the cathode. Charging reverses the flow, pushing the lithium ions to break with the metal atoms and return to the anode.
In the 1970s, Whittingham was one of the first to realize the potential for lithium, an elemental metal that has one “loose” electron in its outermost atomic shell and easily gives it up. But that also makes lithium highly reactive: It will ignite—and sometimes explode—when exposed even to water in the air. Whittingham discovered that titanium disulfide would work well as a cathode: Lithium ions could embed themselves within its layered structure.
Goodenough, realized the cathode could soak up more returning electrons if it was made of a metal oxide instead of a metal sulfide. These compounds were also layered and did not significantly expand or contract when taking up or releasing lithium ions. He found that cobalt oxide worked well, and in 1980, published results for a 4-volt battery, nearly twice as powerful as Whittingham’s.
During the oil crisis in the 1970s, Stanley Whittingham, now at Binghamton University in the US, developed the first ever lithium battery. The positive electrode, or cathode, consisted of titanium disulphide containing lithium ions. Lithium is the lightest metal, so using lithium ions makes batteries lighter.However, the negative electrode, or anode, consisted partly of metallic lithium, which is highly reactive. As the battery was recharged, slivers of metallic lithium grew out from the anode. When they touched the cathode they short-circuited the battery, sometimes resulting in an explosion. In 1991, the lithium-ion batteries were launched commercially. Because they were lighter and more powerful than other kinds of rechargeable batteries, they made it possible to develop more powerful and portable electronic devices – such as mobile phones.
The technology is still being improved. Modern lithium-ion batteries have iron phosphate cathodes developed by Goodenough, which is more environmentally friendly than cobalt oxide.