Akira Yoshino: Inventing The Lithium Ion Battery

Dr. Akira Yoshino, father of the modern lithium ion battery and 2018 Japan Prize laureate, talks to Asian Scientist Magazine about energy, the future of cars and how curiosity makes a career.

AsianScientist (Jun. 1, 2018) – Not many people can boast of having sat down with Japan’s emperor for a meal, but Dr. Akira Yoshino has had that distinct honor.

“I had a frank chat with the Emperor,” Yoshino said in an interview with Asian Scientist Magazine.

About what, he can’t say, but the encounter at the Palace Hotel Tokyo was clearly something to be remembered, given that it could be one of the last times anyone might meet the outgoing Emperor Akihito before his retirement in 2019. Moreover, the banquet honouring the winners of the Japan Prize is the only event at which the Emperor dines outside of his own quarters, let alone with any outsiders.

The Japan Prize—established in 1982 by the Japanese government and Mr. Konosuke Matsushita, founder of what is now Panasonic—is awarded annually to scientists not just for their original ideas, but also for serving “the cause of peace and prosperity for mankind.”

Previous winners include Emmanuelle Charpentier and Jennifer Doudna, discoverers of the revolutionary CRISPR-Cas gene editing technology; Charles Kao, the Chinese scientist who pioneered the use of fiber optics in telecommunications; and Kary Mullis, the inventor of the polymerase chain reaction used to amplify DNA in labs.

Laureates receive ¥50 million (~US$450,000) and a solid gold medal presented by the Emperor. Yoshino’s claim to the prize? It’s probably sitting in a device right next to you—the lithium ion battery.

Building a better battery

Digitization, the IT revolution, the mobile revolution—none of these would have been possible without a compact, lightweight source of power with a high storage capacity and long life. None of these were available until Yoshino’s unique combination of materials and insights made the lithium ion battery practical.

Dr. Akira Yoshino (left) receiving his award at the Japan Prize ceremony and banquet. Credit: Japan Prize Foundation

Akira Yoshino was born in 1948, growing up in Japan’s second biggest city and industrial powerhouse Osaka. After graduating from Kyoto University, he got a job at Asahi Chemical Industry Co. and began researching a material called polyacetylene, which has the ability to conduct electricity despite being an organic substance.

At the time, many were trying to develop a better battery—one that was rechargeable—to meet the growing demand for mobile devices; existing batteries tended to be single-use only. Many scientists were experimenting with lithium—the most oxidizable of elements—as the positive electrode (anode). The problem was that the system was highly flammable and prone to short-circuiting over the course of multiple charges and discharges.

Safety by design

Yoshino looked at using polyacetylene as an anode but couldn’t find a suitable material to pair it with as a cathode (negative electrode). Then in 1983, he came across a paper reporting on a new cathode made of lithium cobalt oxide. Yoshino eventually paired this with another carbon-based material as an anode to form a working combination.

But a rechargeable battery is a complex system. To be practical and commercially viable, particularly to endure repeated recharging, it has to be safe while maintaining high performance. Thus, Yoshino perfected an extremely thin polyethylene-based porous membrane to separate his anode and cathode. This provides a crucial safety feature: lithium ions move between the pores of the membrane, but when the battery overheats, the membrane melts, closing off the pores, thereby halting the function of the battery and preventing an otherwise explosive turn of events.

Yoshino also developed an aluminium foil as a collector to draw electricity from the cathode. This dramatically improved the battery’s performance, conferring it with a high voltage and a high storage capacity.

Yet, there was no overnight success. Despite debuting in 1991 and being championed by Sony, the use of Yoshino’s invention was primarily restricted to video camcorders. Only in 1995 and at the dawn of the era of Windows 95 did the lithium ion battery become thrust into the spotlight.

The next lap: electric vehicles

Looking ahead, Yoshino thinks that the energy sector is ripe for disruption, and electric cars are harbingers of this disruption. Lithium ion batteries are a cornerstone of hybrid electric vehicles, helping the world cut down on environmentally damaging emissions.

“There are two aspects to this: environmental friendliness, and cost,” he says.

Unfortunately, if you optimize for one, it’s often at the expense of the other, hence the cost of electric vehicles right now is relatively high.

The real driving force behind an electric vehicle revolution, however, will be AI and self-driving technology—when they become commonplace.

“What will change is the social value of the car, from a simple transportation method to get from A to B, to a space where we get services,” he says.

Much like how the phone has evolved from a simple communication device, the freedom afforded by automated cars will make it a space to consume media, organize our day, check our finances, maybe even monitor our health.

These service-intensive vehicles will need more power and longer lifespans. It has also been predicted that retired lithium ion batteries from cars will be increasingly recycled to store energy from renewable sources, such as solar power.

“The application of the lithium ion battery to electric vehicles is advancing at a rapid rate today,” Yoshino said in his Japan Prize acceptance speech. “This development takes place against the backdrop of global environmental problems, a major challenge facing all of humankind. I believe that the lithium ion battery’s next mission is to present a solution to these problems. Encouraged by this Japan Prize, I will continue to dedicate myself to such research.”


Copyright: Asian Scientist Magazine; Photo: Asahi Kasei Corporation.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Mun Keat Looi is a science writer and features editor. He is a commissioning editor for the award-winning longform science magazine Mosaic, and an author of the books ‘Big Questions in Science: The quest to solve the great unknowns’ and ‘The Geek Guide to Life.’

Related Stories from Asian Scientist