Akira Yoshino (c) EPO
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Update: After winning the European Inventor Award 2019 in the non-European country category, Akira Yoshino has received the Nobel Prize in Chemistry.

Akira Yoshino has revolutionized the battery. This achievement has now been honoured with the 2019 European Inventor Award 2019 in the non-European country category. During the award ceremony, he said he was pleased to see that his innovation had nowadays found its way into the hands of almost everyone. As without his small, lightweight, secure and rechargeable lithium-ion battery, the power supply of smartphones and laptops would likely not have been possible. Innovation Origins spoke with the researcher on the sideline of the event in Vienna.

Yoshino began developing rechargeable batteries in 1981 at a time when batteries were large, heavy and expensive and were not suitable for powering mobile electronic devices. Lighter alternatives based on lithium often exploded or caught fire. Yoshino completely dispensed with lithium metal in the anode battery. Instead, he used a safe, electrically conductive plastic: polyacetylene. He later substituted this with a carbon compound. He then switched the cathode material for lithium cobalt oxide. In addition, he integrated a heat-sensitive polyethylene-based membrane between the reactive layers. This membrane melts when the battery becomes too hot, acting as a fuse which prevents the entire battery structure from starting to burn.

The lithium-ion battery patent as we know it today was filed by Yoshino in 1983. In 1991, Sony and Asahi were the first companies to commercialize the lithium-ion battery. Until 2016, Asahi Kasei’s world market share for lithium-ion battery separators was 17 %. In 2017, the global market value for lithium-ion batteries was estimated at 26.5 billion euros. A growth of more than eighty billion euros has been projected for 2025.

You’ve filed sixty patents so far. Are all these patents part of the lithium-ion battery sector?

Yes, all sixty patents are for lithium-ion batteries. These patents are valid for twenty years. Some have already expired, others are still in effect. But all of the technologies are still in use.

What fascinates you most about your research field?

(Laughs) What makes me happy is the fact that new markets are constantly emerging for the technologies I have been developing. Some of these new markets are just appearing. The first devices which required small, lightweight, rechargeable batteries were mobile phones and laptops. Now a new market is emerging for electric vehicles. I find this development incredible and it makes me happy to work in another field with so much potential.

They are still working on improving the safety and efficiency of lithium-ion batteries. What is your current research problem?

Safety is a critical and crucial parameter. We are therefore continuing our research in this area. I think that the solid-state battery will be a big step forward in terms of safety – but also in terms of efficiency. This is a new field.

The lithium-ion battery is still the most efficient. But there are also efforts to develop new battery types – like the magnesium battery at the Helmholtz Institute. How do you feel about that?

It remains to be seen how these new alternative technologies will develop and whether they will make a breakthrough. That’s what matters. What we definitely can say is that the solid-state battery has made a breakthrough. Note that for solid-state batteries, both the electrode and electrolyte types are made of a solid (non-liquid) material. They are quick to load and are non-flammable.

In Europe, there is also research on sustainable batteries, such as those made from leftovers from apples. A research project at the Helmholtz Institute has led to this research. What do you think about sustainability in rechargeable batteries?

(Laughs) When it comes to the sustainability of batteries, there are two approaches: First, a battery must do its job and provide the best possible storage capacity for electricity. This guarantees high efficiency and sustainable use of electricity. The next question is: How to make the battery itself sustainable. We need to develop recycling technologies for batteries. We do not use lithium metal in our anodes. However, the cathode in particular, where we use lithium cobalt oxide, must be recycled.

About Akira Yoshino

Born in 1948 in Suita (Osaka), Yoshino studied petrochemistry and earned a doctorate in engineering. Since 1972 he has been working for the chemical group Asahi Kasei in the Tokyo prefecture. Today he holds the position of General Manager of the Yoshino Laboratory and is also the president of the Lithium-Ion Battery Technology and Evaluation Center (LIBTEC). Since 2017, the researcher has also been a professor at the private Meijō University in the Aichi prefecture. He has already been awarded several prestigious prizes for his work. Yoshino is a Fellow of the Chemical Society of Japan. In 2013 he received the Global Energy Prize (Russia) in 2013, the Charles-Stark-Draper-Prize from the United States National Academy of Engineering in 2014, and the Japan Prize in 2018. Last but certainly not least, in October 2019, Akira Yoshino has received the Nobel Prize in Chemistry.

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