In June 2019 the Japanese chemist and engineer Akira Yoshino was one of the recipients of the European Inventor Award. He won the category “Non-EPO countries” for inventing and refining the lithium-ion battery technology. A few months later he was announced as one of the three Nobel Laureates in Chemistry, for the same pioneering work in rechargeable batteries.

The first modern lithium-ion battery

Yoshino was born in 1948, in Suita in the north of Osaka, Japan. He studied petrochemistry at Kyoto University. He became interested in chemistry in fourth grade, after his teacher had introduced him to “The Chemical History of a Candle”– a collection of lectures by 19th century British chemist Michael Faraday. The texts made him curious and he wanted to understand more. After completing his Master’s degree in 1972 he joined the research division of Asahi Kasei, where he still continues to serve as an advisor and Honorary Fellow. He also holds a PhD in engineering from Osaka University, and is the head of Japan’s Lithium Ion Battery Technology and Evaluation Centre, and also teaches at Meijo University.

Yoshino’s Nobel achievement was the development of the first modern lithium-ion battery in 1983. He introduced a safer anode material and a heat sensitive membrane. Yoshino understood that using a polyacetylene anode and a lithium cobalt oxide cathode could make his invention more stable than other rechargeable batteries in development at the time.

“Previously, rechargeable batteries used water as the solvent for the electrolyte. However, water is electrolyzed into hydrogen and oxygen when the voltage is over 1.5 volts. For that reason, getting more than 1.5 volts was practically impossible. So I used organic solvent instead of water, and using carbon as negative electrode I was able to get over four volts. With lithium cobalt oxide as positive electrode material, I created the world’s first LIB,” he explains in an interview on Asahi Kasei’s website.

Changing the world

Receiving the European Inventor Award was no surprise for those who have followed Yoshino’s career. Already in 1983 he filed a patent application for the lithium battery and he is today an inventor of 56 Japanese and six European patents, applied over four decades, according to the EPO and Groth & Co.

“His technology has transformed our society, in part because the licenses granted to other companies for the use of his patented inventions helped to decisively speed up its commercialization,” says EPO President António Campinos. 

Up until 2016 Asahi Kasei held 17 percent of the total global market share of lithium-ion battery separators. The battery market value was estimated to €26.5 billion and by 2025 the market is estimated to reach over €80 billion, according to Groth & Co.

”In Yoshino’s portfolio it is foremost two patent families that stand out as particularly important – one from 1986 and one from 1991. The first one is quoted in close to 500 subsequent patent applications, which is an indication that the patent has become incredibly significant for the technology development within the field,” says Dag Stålhandske, Patent Consultant at Groth & Co.

Throughout his career Yoshino has continued to improve the technology, boosting battery performance and refining safety features.
“My inventions have led to many patents for my company,” says Yoshino. “The patents are not used to keep people out, rather we license our patents to encourage many other manufacturers to use our technology. Some of my latest innovations are for batteries for electric vehicles – and these, I hope, will change the world again.”

The mind of an inventor

In an interview on Asahi Kasei’s website Yoshino says that there were a lot of R&D of portable electronics in the 1980s and small and lightweight batteries with high density and rechargeability were needed.

“But nobody really knew what kind of rechargeable battery was going to be needed. The big buzzword at first was “portable,” and was soon joined by “cordless” and “wireless.” I just sort of sniffed out the direction that trends were moving. You could say I had a good sense of smell.”

In the same interview he says that in order to come up with new ideas he tries to consider what the world really needs, based on his own experience in daily life. “Then I think about how technology can be a means to accomplish it. I’ve found that it’s more likely for a good technology idea to pop into my head when I’m relaxing, with a clear mind, rather than when I’m concentrating hard trying to think of something.”

Right after the Nobel announcement Yoshino told Adam Smith from Nobel Media that the key to his creativity is “to keep thinking” and to never take a holiday from thinking.
“It’s not easy to find answers to research questions if you think only about your field of expertise. It is important to expand your views by being interested in different things,” he told reporters after the Nobel announcement.

In the interview with Asahi Kasei Yoshino says he thinks there will be a revolution, similar to the one in IT 1995, but in the field of energy. “Preparations for the upcoming revolution are already advancing. One thing that never changes is that scientists who clearly grasp society’s emerging needs and boldly take on new research challenges will be the leaders who open the path to the future.”