Electrochemical Solutions to Global Warming

The Koç University Rahmi M. Koç Medal of Science was created to inspire and encourage scientific progress. The award recognizes successful, pioneering scientists educated in Türkiye who have contributed to universal knowledge either domestically or abroad. Now in its seventh year, in 2022 the medal was awarded to Prof. Bilge Yıldız from the Massachusetts Institute of Technology (MIT) for her globally influential work and contributions to science, engineering and medicine. We met with Bilge Yıldız to talk about the groundbreaking research for which she received the award, as well as her ongoing work and future research plans.

KURIOIUS – You have projects such as the electrolysis of carbon dioxide with solid fuel cells, which also have the potential to solve environmental problems. Electrolysis is a known method, what is it that you do differently than everyone else?

Bilge Yıldız – Electrolysis has been around for more than two hundred years, and solid oxide electrolysis is also a method that has been studied for a long time. But we need to improve the electrochemical properties of materials and increase their durability in order for this technology to become more energy efficient and more economical. This is where we are trying to contribute, trying to better understand how these materials work or do not work, and improving the chemistry and atomic structure of the material accordingly. So our contribution is in advancing the material in this technology.

What kind of research are you doing that tackle today’s important problems such as converting and storing energy? What type of solutions do you aim to produce in order to increase energy efficiency and therefore contribute to environmental conservation?

Most of our studies on the energy cycle focus on solid oxide fuel cells or solid oxide electrolysis cells. We work with these technologies in clean hydrogen production without emitting carbon dioxide (CO₂) and we also work on new materials, interfaces, and surface chemistry in order to advance the CO₂-free synthesis of ethylene, which is the precursor of ammonia used in fertilizers, and plastics. In other words, we would like to be able to do this synthesis with materials that are more energy efficient and more durable. We can use hydrogen to generate electricity too, and thus we are trying to develop the same platform in that direction as well. The use of hydrogen as a clean fuel, that is, the conversion of chemical energy into electricity through electrochemistry, is more efficient than fossil fuels. The two reactions seem to be the reverse of each other: We apply electricity to water to produce hydrogen and oxygen, or we do the opposite and apply hydrogen and oxygen to produce electricity and water. Even though the reaction seems reversible, the material does not react that way. This is why it is important to develop interface chemistry that can work well in both directions, and we contribute to this goal.

As for storing energy, we are trying to develop batteries that are longer ranged and more reliable than the lithium-ion batteries we use. As you know, there is a risk of fire when the batteries we currently use heat up a little or leak. To prevent this, we would like to replace the electrolyte, which is liquid and organic, with a solid and inorganic substance. These are called solid electrolyte batteries. Although these electrolyte materials have already been developed, such batteries are not currently unavailable in the industry because of the high resistance that is generated at the interface between the electrolyte and the cathode and anode materials. Our studies aim towards understanding how to suppress the structures that may be the sources of this resistance, structures that are formed during the synthesis or electrochemical function of the material.

You have research on producing energy efficient computing hardware devices that are inspired by the human brain. What is the analogy you set up there and what exactly are you trying to do?

We may say they are devices inspired by the human brain, with structures resembling batteries, but functioning more like biological synapses. Before starting this work, I also studied modulating electronic conductivity by using different mechanisms. My first transition to this field was because these devices relied on the same mechanisms as the materials in solid fuel electrolysis cells we work with, and therefore scientifically had a lot in common. In 2018, we started working with IBM at the Massachusetts Institute of Technology (MIT). They asked me if we could perform this function with ions. At that time, I was working on extracting hydrogen from other materials electrochemically. When hydrogen diffuses into metals, it degrades their mechanical properties, causing what we call hydrogen embrittlement. To eliminate this, we were chasing means to renew the material by pumping out the hydrogen with the help of electrochemistry to regain the material’s mechanical properties. I started to think, “We are already doing this with ready-made metals, but would it also work in the other study?” These are devices that have common physical mechanisms and materials but differ in application.

You also took part in NASA’s Mars 2020 project. Could you elaborate on your role in this project?

Before this multi-participant project, there was a company I collaborated with for other projects and worked on solid oxide fuel cells. When the opportunity came up for this project on CO₂ electrolysis in collaboration with NASA, they wanted to include me. Small-sized materials are produced in our laboratories, but they produce larger ones, larger cells with the capacity suitable for the purpose, and even combined structures of these cells. “In this project, we revealed the degradation mechanisms that the material undergoes in CO2 electrolysis on the large structures they built. Additionally, through our own electrochemical studies, we investigated methods we can use to prevent CO2 from degrading the material.”

The cell that eventually went to Mars was a combination of materials developed with this know-how. The role of this material will be to convert the CO₂ in the oxygen-deprived atmosphere of Mars into oxygen required for life. This way, you may be able to obtain the fuel required for a mission planned to return, even if it is unmanned, by using the Martian atmosphere. In other words, this can be used to gradually obtain the oxygen necessary for fuel or to produce the oxygen that astronauts may need for conducting research on the Martian surface for a certain duration. This cell is currently producing oxygen on Mars. In order for NASA to meet its goals, the capacity will need to be increased.

How would you evaluate the possible contributions of our work to humanity or to our Earth?

I think it is necessary to find a solution to global warming by developing clean technologies. And these technologies do not develop spontaneously; we need to better understand the processes that present the materials and technologies to improve our production of the necessary material and design. We need to abandon fossil fuels or stop releasing CO₂ into the atmosphere. We can only achieve this transition through science and technology, and our studies are designed for this purpose. In the problem of global warming, instead of relying on a single solution, it is best to seek the solution through many alternatives.

You were awarded the Koç University Rahmi M. Koç Medal of Science. Receiving a reward is certainly a prestigious achievement, but does it offer other benefits to researchers?

Of course, it is an honour, and a very important one. Although scientists do not work to receive medals, it is great to feel that our work is being recognized and appreciated. Such recognitions lead to an increase in the impact of our work and help establish new collaborations. The awards also help in funding our studies, as they are considered indicators of our work’s quality.

What essential steps should be taken to fulfill young scientists’ most urgent needs, or what steps should be taken to support them?

I have personally experienced how good the basic education in Türkiye is. You will never feel deficient in this basic training wherever in the world you may go. However, I think the part open to improvement in Türkiye is providing young people with more opportunities for research and encouragement. With this encouragement and an environment of equal opportunities, our young people can achieve great success. My advice to young people would be that if they find a subject that interests them and motivates them, they should put their minds to work and try to do their best, without hesitating or worrying about whether it is difficult. In order to achieve something novel, I think it is necessary to be a bit of a “naive optimist” and very hardworking, so that they can focus on the ways of doing it instead of the difficulties.