The invention of rechargeable batteries: An interview with Dr. Akira Yoshino, 2019 Nobel laureate

By Tomoki Sawai, WIPO Japan Office

In 2019, Dr. Akira Yoshino, Dr. Stanley Whittingham and Dr. John Goodenough were awarded the Nobel Prize for Chemistry for their seminal work in advancing the development of lithium-ion batteries, the miniature energy systems that we depend on to power our mobile devices. These lightweight rechargeable power packs have fueled the boom in mobile electronics and are already yielding environmental dividends by enabling the development of long-range electric vehicles and efficient storage of energy from renewable sources.

Dr. Yoshino invented and patented the world’s first lithium-ion battery and has since worked continuously to improve the technology. He has secured over 60 patents on lithium-ion battery technology during his career. Dr. Yoshino talks about the challenges he overcame in developing lithium-ion batteries and the role that strategic use of patents rights has played in building a booming global market for them.

What motivated you to take up chemistry?

I have always been interested in the natural world. And when I was in elementary school one of my teachers suggested that I read The Chemical History of a Candle by Michael Faraday. And that stirred up a lot of questions for me. I hadn’t been interested in chemistry until then. That’s how it all started. I then went on to study quantum organic chemistry at the University of Kyoto.

And how did you come to work on lithium-ion batteries?

In the early 1970s, I joined the Exploratory Research Team at Asahi Kasei Corporation to explore new general-purpose materials. The projects I worked on initially didn’t work out, so I was looking for a new research focus. At the time, there was great interest in polyacetylene, a fascinating electro-conductive polymer that had been predicted by Dr. Kenichi Fukui, Japan’s first Nobel Laureate in Chemistry, and discovered by Dr. Hideki Shirakawa, winner of the 2000 Nobel Prize for Chemistry.

At first, I explored practical applications for polyacetylene. But at the time, Japan’s electronics industry was looking for a new lightweight and compact rechargeable battery to power the mobile devices they were developing. Many researchers were working on this, but existing anode materials were unstable and raised serious safety concerns – a new anode material was required. My research on polyacetylene suggested that it could be used as an anode material (because lithium-like cations move in and out of it), so I started experimenting with it and it worked.

My basic research on lithium-ion batteries began in earnest in 1981, the year Professor Fukui won the Nobel Prize for Chemistry. Interestingly, research into lithium-ion batteries has been supported by eight Nobel laureates, which gives an indication of how challenging their development has been.

By 1983, I had come up with a new type of rechargeable battery using a combination of polyacetylene for the anode and lithium cobalt oxide for the cathode. Dr. John Goodenough, one of my fellow laureates, had identified lithium cobalt oxide, the first cathode material to contain lithium ions, in 1980.

How did your research evolve following this breakthrough?

All went well for a while. The prototype was one-third lighter than a standard nickel-cadmium battery, which was good, but we only achieved a slight weight reduction and were unable to reduce the size of the battery. This put the whole venture into question because miniaturization was a priority for the electronics industry.

The problem was the small relative density of polyacetylene, which made for a lightweight but bulky battery that was too big to be practical. We began looking for a higher density material with polyacetylene-like properties. The idea was to use a carbon material (it has a relative density of about 2.2 and is made of the same conjugated double bonds as polyacetylene). But no suitable carbon material existed, which was very disappointing.

Lithium-ion batteries have made today’s mobile IT society a reality. And in the future, they will play a central role in building a sustainable society.

However, the answer came from within Asahi Kasei; another research team had developed a new carbon material with a distinctive crystalline structure, known as Vapor-phase Grown Carbon Fiber (VGCF), that made it a good substitute for polyacetylene. I managed to get hold of a sample of the material and, sure enough, when we used it to make the anode, we created a lightweight and compact battery.

How did you learn about the importance of miniaturization?

As we were not battery specialists at Asahi Kasei, in-house discussions about what industry needed led nowhere. And of course, you can’t just go to a battery manufacturer and expect them to share their confidential early stage research with you. But I met a former classmate of Asahi Kasei’s executive officer who was a battery company executive and he highlighted the importance of miniaturization – smartphone manufacturers needed batteries that could fit into narrow slots.

For me, this highlights how important it is for people from different fields to get together to discuss and exchange their ideas. Such collaboration is extremely important in fostering technological development as well as the broad circulation and uptake of new technologies.

Was Asahi Kasei Corporation’s general focus on materials science advantageous for lithium-ion battery development?

The initial plan was to develop new polyacetylene-based materials, but as the research progressed, we realized multiple new materials were needed by industry – for cathodes, electrolytes, separators and so on. Rather than focusing on simply making a new anode, the image of a battery emerged. Asahi Kasei got into the battery field simply because it was researching new materials and was able to develop the lithium-ion battery precisely because it was not a specialist in the field.

Had I been a researcher with a battery manufacturer, I probably wouldn’t have encountered polyacetylene or VGCF. In the end, new materials and the freedom to develop them are what trigger new products.

What has been the impact of lithium-ion batteries?

Lithium-ion batteries have made today’s mobile IT society a reality. And in the future, they will play a central role in building a sustainable society. A rechargeable battery with the ability to store electricity is a key device for solving environmental problems. This became more widely recognized around 2010, when electric vehicles (EVs) came on the scene. That was the year the Nissan Leaf was launched. It was a truly epoch-making advance. From then on, lithium-ion batteries were used to power EVs. Since then, a lot of progress has been made in improving the energy density of lithium-ion batteries (i.e. how far you can go on a single charge), and in lowering costs. But issues around durability (the life of the battery) still need to be overcome.

Although lithium-ion batteries alone will not solve all environmental problems, when combined with other new innovations, like artificial intelligence (AI) and the Internet of Things, they will be central to building a sustainable society.

As the holder of multiple patents, what are your views on the patent system?

The fundamental spirit of patent law is to encourage technological development for the benefit of all. In return for acquiring exclusive patent rights, you reveal [disclose] a new technology to the world, and thereby support its broad dissemination. That is what happened with lithium-ion batteries.

Asahi Kasei was good at developing battery technology, but was not a battery specialist, so we had to decide what kind of business to build around the technology. After much discussion, we decided to: a) team up with a suitable partner (Toshiba) to establish a battery business; b) integrate other battery-related materials into Asahi Kasei’s existing business; and c) to actively license lithium-ion battery technology.

The licensing program opened lithium-ion battery technology up to many new manufacturers, which allowed for the technology to be improved in terms of its cost, reliability and safety. It also helped the technology to spread, strengthened consumer confidence and generated licensing revenues for the company. Everyone could access the technology quickly and benefit from it. That’s the whole point of inventions.

How do you think the intellectual property system needs to improve?

In today’s globalized world, it has become difficult to exercise exclusive patent rights on patents. Even if you tell people not to imitate, they do! Moreover, patent rights are time limited so it is very difficult to take advantage of their economic value through licensing alone. I think it is important to think about other ways to get a payback or financial return. For example, this might involve developing a business model around lithium-ion batteries where the technology is commercialized as a service, rather than an end product, and you receive downstream payments. Platforms like Google, Apple, Facebook and Amazon use this model. It offers a better return. They have succeeded in designing platforms and in establishing a global standard that has expanded the market for their technology-based services. Some are even provided free of charge. Google, for example, provides its OS Android system for smartphones free of charge to expand the Android-user community. Here we see that the value of the smartphone business doesn’t come from the phone itself but from its use. This business model is common in the IT world, and may well become the way of the future.

Did the patent system help you to win the 2019 Nobel Prize for Chemistry?

Researchers from industry differ from academic researchers in the way they announce their results. Academic researchers publish their work, whereas the work of industrial researchers is embedded in patent literature, which is hard to understand and, until recently, was not highly considered in academic circles.

However, the Nobel Committee’s citation did refer specifically to the prototype of the lithium-ion battery I had created and patented in 1985. So, it seems to have been an important factor. An endorsement from an independent authority also seems to have played a role. I had won the European Patent Office’s European Inventor Award for having patented the first patent for lithium-ion batteries – recognition from the European Patent Office for that patent seems to have been an important factor in the screening discussions for the Prize.

My advice to young people is: be curious and use your energy to develop the skills, the confidence and the knowledge to make the big discoveries and the groundbreaking inventions that will mark this century.

In general, I think industrial researchers are handicapped when it comes to Nobel Prizes because, typically, only patent examiners, for whom I have great respect, can understand the technologies outlined in patent applications. So, if industrial researchers want to be considered for a Nobel Prize, they need to win a major award!

What message do you have for young scientists?

The time frame for taking on new challenges is limited to a certain age; around 35. That’s when successive generations of Nobel Prize winners started their research. I started basic research on lithium-ion batteries at 33. At that age, you understand the workings of a company and of society and have the confidence and authority to start a new venture, and if it fails, you still have time to start something else.

I think Japan’s capacity to produce Nobel winners in the future will be determined by the kind of environment people around the age of 35 are working in today and whether they have the freedom to follow their own way of thinking and to work on the research that can lead to a breakthrough worthy of a Nobel Prize.

What advice do you have for young people with aspirations to become the scientists of tomorrow?

Today, young people can easily access any information they want, but many feel that there are no new big inventions or discoveries for them to unravel. But they are mistaken. There are still so many things we don’t understand about life and nature and many treasures to unearth.

My advice to young people is: be curious and use your energy to develop the skills, the confidence and the knowledge to make the big discoveries and the groundbreaking inventions that will mark this century. There is plenty we don’t know yet. Invest in your future through study. Imagine your 35-year old self and what you could be working on.

In principle, I don’t believe in forcing children to learn. We need to enable them to think for themselves and decide on their own path. I think that’s the best way.