Kyoto University and Toyota test 1,000 km per-charge EV battery

OSAKA – A team of researchers from Kyoto University and Toyota Motor are making solid strides in developing next-generation battery technology, which has the potential to pack much more energy into a small, lightweight package than today’s standard lithium-ion or Li-ion batteries Ion housing. Batteries.

The new fluoride-ion battery that the researchers are working on, which would consume about seven times as much energy per unit weight as conventional Li-ion batteries, could enable electric vehicles to travel 1,000 km on a single charge.

The team has developed a prototype of a rechargeable battery based on fluoride, the anion – the negatively charged ion – of elemental fluorine. A fluoride ion battery, or FIB, generates electricity by moving fluoride ions from one electrode to another through an electrolyte that conducts fluoride ions.

The prototype was created by a team of researchers led by Yoshiharu Uchimoto, professor at Kyoto University. It uses an anode or negatively charged electrode made from fluorine, copper and cobalt, and a cathode or positively charged electrode made mainly from lanthanum. The researchers have confirmed that the prototype has a higher theoretical energy density, potentially giving it a range up to seven times longer than today’s Li-ion batteries.

The range of electric vehicles has increased significantly over the years as the performance of the Li-ion battery and energy recovery systems for deceleration have been improved, and the battery is charged with electricity generated by braking. For example, some of the latest EV models from Tesla and Nissan Motor can travel up to 600 km per charge under ideal conditions. However, experts say that the energy density of Li-ion batteries is theoretically limited, which means that their range cannot be extended significantly.

Researchers at Kyoto University and Toyota turned to FIB because of their theoretically higher energy density. This results in smaller, lighter batteries that perform as well as Li-ion cells or, if they are the same size and weight as today’s Li-ion batteries, could give longer juice between charges.

The researchers opted for a solid electrolyte instead of the liquid ones normally used in Li-ion batteries. A key advantage of such solid-state batteries is that they cannot ignite, so engineers don’t have to worry about creating systems to prevent overheating.

The researchers bet that a solid-state FIB battery can solve the puzzle of building an electric vehicle that can be 1,000 km long on a single charge. However, many experts remain skeptical.

The biggest challenge is that FIBs have only worked at high temperatures so far. It is only known that fluoride ions are usefully conductive, that is, move toward a polarized electrode when the solid electrolyte is heated sufficiently. This makes FIBs impractical for many consumer applications. The high temperatures required also cause the electrodes to expand.

The Kyoto University-Toyota team figured out how to keep the electrodes from swelling by making them from an alloy of cobalt, nickel and copper. The team plans to optimize the materials used in the anode to ensure that the battery can be charged and discharged without losing capacity.

In 2018, scientists from the Honda Research Institute, along with researchers from the California Institute of Technology and NASA’s Jet Propulsion Laboratory, reached a major milestone with FIB technology: the ability to operate power cells at room temperature instead of heating them to high temperatures.

In an article published in Science, co-author Robert Grubbs, a Caltech researcher, says, “Fluoride batteries can have higher energy density, which means they can last longer – up to eight times longer than batteries used today.”

Further studies in Japan and overseas are ongoing to find an alternative to Li-ion batteries, with magnesium and aluminum ions being among the promising candidates.

The race to develop such a battery is intense. Those who develop the highest performing rechargeable batteries will become world leaders in this important technology, says Yasuo Ishiguro, executive director of the Lithium-Ion Battery Technology Consortium and Evaluation Center, a research facility in Osaka.

The battery market is lucrative. Global sales are projected to exceed 6 trillion yen ($ 56 billion) in three years.

Advances in rechargeable battery technology are not only leading to better electric vehicles. As a result, they can serve as a ubiquitous form of storage of electricity from renewable sources such as solar energy and provide society with clean energy.

The new battery technology will allow us “to create a new society without making massive infrastructure investments,” says Akira Yoshino, an employee at chemicals maker Asahi Kasei, who received the Nobel Prize in Chemistry in 2019 for his contribution to developing an economically viable ion batteries .

Researchers around the world are competing to make better Li-ion batteries. A LIBTEC project aims to develop solid-state Li-ion battery technology by April 2023. Toyota and Panasonic are involved in the effort.

Despite growing hopes for FIBs, they won’t hit the market for a while. Many experts believe that it will be sometime in the 2030s before commercially viable FIBs are available. A prototype Li-ion battery was developed in 1985, but the batteries did not become commercially available until 1991.

The biggest challenge for engineers is finding the best combination of elements – which ions should be used and which chemicals should make up the electrodes and electrolytes. The combination makes a significant contribution to determining battery performance.

Ishiguro emphasizes Japan’s advantages in this race, referring to the technological capabilities of the country’s universities, automakers and materials manufacturers. However, Japan is less good at chemistry and the systems integration required to maximize product performance. The battle for battery supremacy will be fierce.

The winners are likely to be those who make the most effective use of cutting-edge technologies and advanced manufacturing techniques, such as artificial intelligence-based “materials computing”. This includes applying the principles of computer science – using information science to solve problems – to materials science and engineering to achieve development goals.

The US and China, leaders in next-generation AI and computing technology, will be great competitors in battery racing.

To keep up, Japan also needs a strategy that includes mass production and market development. Japanese companies have bitter memories of losing their lead in the global Li-ion battery market around the year 2000 to new competitors from China and South Korea who captured market share with cheaper products. Companies in all of these countries are keen to make a claim in the market for batteries that will power the future.

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