October 16, 2019 by Sam Holland
For their past lithium-ion research, which was pivotal in realising today’s world of portable, rechargeable devices, 3 scientists were awarded the Nobel Peace Prize in Chemistry on the 9th of October.
The scientists, M Stanley Whittingham (77) of Binghamton University, John B Goodenough (aged 97—making him the oldest Nobel winner in history) of the University of Texas at Austin, and Akira Yoshino (71) of Meijo University, will all receive equal shares of the 9 million Swedish Krona (£740,000 at the time of the award) prize.
The honours, which were awarded by The Royal Swedish Academy of Sciences, were deemed by the respective 3 researchers a “great”, “wonderful”, and “amazing” surprise.
Left to right: Nobel Prize award-winning lithium-ion scientists John B Goodenough, M Stanley Whittingham, and Akira Yoshino. Image credit: The Royal Society.
The scientists’ now-award-winning research was chiefly called for due to the oil crisis in 1973: a new power solution was needed that required no fossil fuels. The 1970s campaign began with Whittingham, who was tasked by his then-employers, Exxon (now ExxonMobil), with finding such an alternative energy source.
The success of Whitingham and his colleagues’ project—which was even instrumental in the progress of the hybrid vehicle—was first sparked by the discovery that lithium ions could be reliably shuttled from cathode to anode and vice versa (ensuring Li-ion’s hallmark that we enjoy today: efficient rechargeability). This was established by having the ions successfully integrated, i.e. intercalated, within plates of titanium disulfide, aka TiS2. (While TiS2 was at the time used to form a Li-ion battery cathode, such cathodes are nowadays chiefly cobalt-based—more on this later.)
Of course, rechargeable batteries were nonetheless already familiar technology at the time. This was in the form of lead-acid batteries (which are still used in many vehicles), but their cumbersome build was just one of the many reasons that they could never have the same universal appeal—particularly in regards to consumer technology—that lightweight Li-ion cells enjoy.
Compare and contrast. A lead-acid battery (top) and a lithium-ion battery (bottom): both rechargeable—but the former is bulky, while the latter is comparatively lightweight. Credit for each image: Wikimedia Commons.
In fact, the potential applications of lithium were no secret in the ’70s, either; however, the previous research into the highly-reactive metal had not established a safe way for it to be exploited without a significant risk of explosion. And while many—even modern—Li-ion batteries are still at least somewhat combustible, it was the following 3 discoveries, respectively observed by Whittingham, Goodenough, and ultimately Yoshino, that meant the technology could one day be confidently released to the world.
As covered, it was Whittingham’s anti-fossil fuel research, particularly the introduction of the TiS2-based Li-ion plates and cathode, that led to a potential-rich (namely 2+ volts) power source: one whose said material housed the spaces required for efficient lithium-ion intercalation.
Again though: metallic lithium in itself is volatile, so the research remained unviable. As per Nobel’s press release, this was until John Goodenough, in 1980, correctly predicted that the cathode should be metal oxide rather than metal sulphide-based: having then demonstrated that the result—namely cobalt oxide—produced up to 4 volts, the path had been made for powerful, commercial batteries.
In fact, it was just 5 years later that Akira Yoshino created the first commercially-viable Li-ion batteries. For the first time, these early—yet breakthrough—power sources consisted of petroleum coke (rather than lithium) anodes, and it was this carbon-based makeup that proved intercalation-friendly, just as its cobalt oxide cathode counterpart was.
Now, over 3 decades later, you’d be hard-pressed to find a portable device that isn’t powered by the lightweight, durable technology; and plenty of further Li-ion-inspired innovations are well underway, too.
As Whittingham told Nobel Media in the post-award phone interview: “The field started off small and it has just mushroomed since then. It’s great to see all the changes—how it’s impacting everybody’s lives”.
