[No. 37] Kazuaki Nakagawa

My first encounter with the Yagami Campus of Keio University was when I was in my second year of junior high school and was given a tour of a laboratory in the electrical engineering department. As a science-loving boy who was the head of the science club, I had asked my father's cousin, who was enrolled in the Faculty of Engineering, if I could see the university. I remember being very surprised to see a large printer connected to a computer printing out one picture after another of a woman in a kimono drawn with typed characters. It made me want to go to the Faculty of Engineering. I struggled with English, which was my weak subject, in the university entrance exams, but my strength in mathematics helped me. I must have gotten a perfect score on the Keio exam in mathematics, and I recall being fully prepared to enroll without even waiting for the announcement of successful applicants.

For a student coming from an all-boys school in Utsunomiya, everything about life on the co-ed Keio Hiyoshi Campus was new and fascinating, and I was impressed by the energy of my seniors at campus events like the Waseda-Keio rivalry and the Mita Festival. During this period, my life revolved around the activities of a club called the Piano Club. While I gained a wide range of knowledge, I found myself in the dishonorable state of not understanding the content of my specialized classes even when I attended them. Fortunately, in my third year, after advancing to the Department of Applied Chemistry, I was drawn to Professor Takashi Yamaguchi's brilliant lectures and became particularly interested in two subjects: chemical thermodynamics and its extension, electrochemistry. I recovered to the point where I would visit his laboratory to ask him questions. My interest in these two subjects would dramatically change the course of my research career twelve years later.

When it came time to choose a laboratory in my fourth year, I joined the Electrochemistry Laboratory because of my interest in batteries. At that time, lithium batteries had not yet become practical, and I was researching how the choice of electrode materials affected the battery's output and charge-discharge cycle characteristics. It feels like a different era now, with lithium batteries being used as a matter of course to power mobile phones and personal computers. The atmosphere in the laboratory was extremely family-like, and I was surprised that there was an event called a Christmas party for the purpose of finding girlfriends for the male students who were engrossed in their research. I struggled until I completed my master's program with the strict rule (?) that we must bring a partner. In comparison, job hunting in the spring of my second year of the master's program was easy, thanks to my academic advisor and seniors. I was attracted by the corporate culture of Toshiba, my current employer, which I had heard about from an acquaintance, and by the simple reason that its Research Centers and Institutes were geographically closest to the university. I made my decision quickly and only visited Toshiba.

In my job interview with Toshiba, I appealed for a job related to energy issues and secured an assignment to the Research Centers and Institutes, but the first department I was assigned to was a research team for fluorescent materials. There, for about four years, I was mainly in charge of work related to improving the three-band fluorescent lamps that were becoming popular at the time. To increase luminous efficacy, fluorescent materials are basically required to have a pure white color, and I repeated experiments with solid-state reactions using an electric furnace and a crucible. On reflection, it was a study with very high commonality with my research on lithium batteries, with the only changes being that the black powder I had handled as a student became white powder, and the measurement of battery characteristics changed to spectroscopic measurements. I remember being strangely impressed, thinking that the company thinks carefully about its personnel allocation.

Later, when the organization of the Research Centers and Institutes was about to change, I requested a transfer to a fuel cell research team, which was closer to my original interest in energy, and was put in charge of developing what is called the second-generation fuel cell, the molten carbonate fuel cell. Here, I was required to find an effective countermeasure to the problem of the electrolyte plate, a submicron porous body for retaining the electrolyte, deteriorating during fuel cell operation. Ultimately, we discovered that a significant improvement could be obtained by converting the gamma-phase lithium aluminate (γ-LiAlO2) into the thermodynamically stable alpha-phase lithium aluminate (α-LiAlO2) under the fuel cell's operating conditions. For this achievement, our research team of six received an award from The Electrochemical Society of Japan.

On the other hand, there were many failed experiments behind this success. Among them was an experiment to mix lithium zirconate with lithium aluminate. Since it is known that alumina-based and zirconia-based ceramics are incompatible, I thought that mixing them would suppress the degradation of the electrolyte plate. However, the result was a major failure. The lithium zirconate reacted with carbon dioxide in the 650°C fuel cell and changed into another substance. This is when the chemical thermodynamics I had studied with interest twelve years earlier came into play. I immediately understood that the difference between lithium aluminate, which does not react with carbon dioxide in the fuel cell, and lithium zirconate is a difference in thermodynamic properties, and that this failure occurred because the upper temperature limit for the reaction with carbon dioxide is higher for lithium zirconate.

And then came a change in perspective. If it reacts with carbon dioxide in a high-temperature fuel cell, I thought, couldn't it be made into an absorbent that absorbs carbon dioxide at high temperatures? At that time, the development of technology to separate and capture carbon dioxide was being promoted as a national project as a measure against global warming, and it was said that removing carbon dioxide from high-temperature gases of 350°C or higher would be particularly energy-efficient. I immediately started research on carbon dioxide separation on my own, separate from my fuel cell research. Toshiba has a tradition of "under-the-table" research, which allows researchers to use about 10% of their research resources freely, and I took full advantage of this.

Once I was able to get support from the company's business divisions, my work became recognized as an official research team, and I shifted the focus of my research from fuel cells to carbon dioxide separation. I also utilized my knowledge of battery materials from my student days to search for promising candidate materials for the absorbent, and from the time it was first announced, it became a high-profile study that was reported extensively in newspapers and other media. I also received awards from The American Ceramic Society and others. Even now, many researchers around the world, together with Toshiba's researchers, are continuing to conduct research to support and expand on this idea, and I am confident that in the near future, this absorbent will be utilized in various situations in industrial society.

In 2003, I moved into a managerial position, shifting from a role where I directly advanced research and development to one where I consider R&D policy and the application of its results. However, the research experience of about twenty years, which began with an interest in chemical thermodynamics in my third year of university and developed in a more interesting way than I could have ever predicted, is something I am deeply proud of. In a managerial role, the work changes to focus on social and human phenomena, unlike in R&D, but the importance of combining broad knowledge with deep expertise in a specific academic field remains the same. Without broad knowledge, you cannot change your perspective, and without a deep academic specialty, your ideas will be the same as everyone else's. To all the junior students who are about to embark on their academic path at the university, I hope you will acquire a wide range of knowledge through activities outside of class, such as club activities, and also master a specialized academic field that will be your weapon when you need to demonstrate your individuality. At the Faculty of Science and Technology of our Juku, located on the Yagami plateau in Hiyoshi, known as "Oka no Ue," I am sure that many wonderful opportunities to encounter both await you.