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ENDO Morinobu, 2002-08-26

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Morinobu Endo, né en 1946, est Professeur à la Faculté d’Ingénierie de l’Université de Shinshu à Nagano (Japon). Après un Master’s degree à l’Université de Shinshu, et une Thèse en ingénierie à l’Université de Nagoya, il intègre l’université de Shinshu comme chercheur, Professeur associé puis Professeur en 1990. Il y fonde un laboratoire au sein du Department of electrical and electronic engineering. Ses recherches sont dédiées au carbone sous ses diverses formes ; elles vont du fondamental (propriétés physico-chimiques du carbone dans ses multiples formes allotropiques : graphite, nanotubes, carbone nanoporeux) à l’appliqué (fibres de carbone, composés d’insertion au graphite pour batteries et condensateurs). Morinobu Endo est notamment un pionnier des nanotubes de carbone (caractérisés en 1974 lors d’un travail effectué en collaboration avec Agnès Oberlin en France à la Faculté des sciences de l’Université d’Orléans). Ainsi en 1991, date généralement retenue pour la découverte des NTCs par Sumio Iijima, Morinobu Endo avait déjà développé et breveté un processus de fabrication donnant lieu à des usages industriels des NTCs comme composés d’insertion dans des accumulateurs lithium-ion (batteries d’usage courant pour l’électronique portable). Morinobu Endo a co-dirigé des initiatives pour la coopération université/industrie au sein de la Japan society for the promotion of science (JSPS). Depuis 2004, il préside la TANSO (Japan society of carbon). Membre du comité de rédaction de la revue Carbon, il est auteur d’une trentaine de livres sur la science du carbone et de plus de deux cent articles. Ses recherches lui ont valu de nombreuses distinctions : Carbon society of Japan Award, (1995) ; Charles E. Pettinos Award (American carbon society, 2001) ; Lee Hsun lecture series Award (Institute of metal research of China, 2002) ; ShinMai Award (Shinmai Bunka foundation, Japon, 2003) ; Ishikawa Award (Ishikawa carbon science and technology promotion foundation, 2003) ; Medal of achievement in carbon science and technology pour la découverte et la synthèse des nanotubes en 1974 (American carbon society, 2004) ; The Minister of education, culture, sports, science and technology prize for contribution to intellectual Cluster (Japon, 2005) ; Honorary citizen of Suzaka-city (2006) ; Small Times magazine best of small tech lifetime achievement Award (2006) ; JPA lectureship Award (2007).

Pour citer l’entretien :

« Entretien avec Morinobu Endo », par Bernadette Bensaude-Vincent, 26 août 2002, Sciences : histoire orale,

Lieu : bureau de Moronibu Endo, Endo lab, Université de Shinshu, Department of electrical and electronic engineering, Wakasoko, Nagano-shi 380-8553, Japon.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent.

Édition en ligne : Sacha Loeve.

BERNADETTE BENSAUDE-VINCENT (BBV) : In which discipline did you take your degree, and your PhD ?

MORINOBU ENDO (ME) : I started 30 years ago. I graduated from Shinshu University in 1971. Then took a Master in Electronics. I spent one year in a company, Statch. Then I came in this university in 1972 as a Research Associate.

BBV : So you spent your entire career in this University. How and when did you come into carbon science ?

ME : I became interested in carbon as a research assistant. At that time, carbon was considered as a dirty, dusty science, in comparison with the more attractive semiconductor science. But I found it promising.

BBV : Were there people already working on carbon here in the early 1970s ?

ME : Yes my professor Tsumeo Koyama was working on carbon. He was aged already but he asked me to incorporate here.

BBV : Why did you find carbon so promising ?

ME : I read a few pioneering papers by S. Mrozowski and by M. S. Dresselhaus. This encouraged me. At that time, there was an activity in carbon fibers based on Polyacrylonitrile (PAN) for aerospace industry. Industrial companies were most active in this field, especially Toray. There was a concern for new methods for preparing this promising material because PAN-based fibers were high-cost fibers. Professor Koyama asked me to prepare carbon fiber from vapor. This is a carbon fiber directly grown from the decomposition of hydrocarbons such as benzene. Vapor Grown Carbon Fibers (VGCFs) were totally different from the commercial PAN fibers. PAN Fibers are continuous while VGCFs are shorter. They have a unique structure. In the early 1970s I was able to prepare the fiber without understanding the mechanism at work, or what elements were essential.

BBV : So you had the technique but no knowledge of its structure and properties.

ME : Fortunately I had a chance to work in France with Madame Agnès Oberlin at the CNRS in Orléans.

BBV : How did you come in contact with her ?

ME : When I was a Research Associate in this university, I wrote a paper in Japanese showing that very beautiful carbon fibers can be grown by gas pyrolysis. A nice Japanese professor who was a good friend of hers, introduced my work to her. He invited her in Japan as a visiting professor and she asked to meet with me. I traveled to France with my fiber in 1974 and I worked in her laboratory for one year. In Orléans they had an electron microscope in 1973. I found that there were small opaque particles at the tip of the fibre (figure 1). In order to use the electron microscope it was necessary to use very thin fibers. For that it was convenient to stop the growth process at an early stage. I thus found that the fiber had an hollow core and later in the growth process the diameter of the fiber increased. Here on this picture you can see the particle. I found with Agnès Oberlin that this particle was iron. This result was published in France in 1976 in a paper entitled “Filamentous Growth of Carbon Through Benzene Compounds” (Journal of Crystal Growth 32 (1976) 335). In this paper we argued that VGCF had a “hollow core” which is the strongest part of the fiber. It never breaks when the fiber breaks. Sometimes you have cross-linkings of the fibers. Here just at the center of the fiber you can see the single wall nanotube (figure 2).

Figure 1. “Hollow core” in a vapor grown carbon fiber, 1976

Courtesy of Morinobu Endo.

Figure 2. Cross-linked single-wall nanotubes, 1976

Courtesy of Morinobu Endo.

BBV : Nanotubes ? You did not name it as such in 1976 ?

ME : We called it “hollow core” or “central tube”. Here you can see the fine particles at the tip (figure 3). By using bright- and dark-field image I found that they were Fe3C. This is the chemical product after cooling. At the end of the growth the particles should be iron. I suggested a growth model : the fiber first forms over this fine particles of iron then grow in the radial directions.

Figure 3. “Central tube” in the core of a vapor grown carbon fiber, 1976

According to Dr. Endo, this “central tube” is a double-layered carbon nanotube. Courtesy of Morinobu Endo.

BBV : Where this iron came from ?

ME : We were able to understand where it came from. We used a special sand-paper as a substrate. Without this sand-paper, no fiber. With this sand-paper that we used in France, we got beautiful fibers. We analyzed the electron barriers and we found that it was Fe2O3. Iron oxide coming from the sand-paper proved to be very important as a catalyst to generate the carbon fiber.

BBV : So you understood the mechanism when you came back to Japan ?

ME : I came back in 1975. I clearly described how the fiber grows, including the seeding methods, in a paper published in 1988, “Grow Carbon Fibers in the Vapor Phase” (American Chemical Society - ChemTech 18 (1988) 568-576). In a way this fiber grows in two steps : 1) this very thin fiber, the hollow core ; 2) the secondary process is the thickening of the fiber.

BBV : Do you mean that it took you about 10 years to understand the process ?

ME : No in 1988 it was already established. It is a review paper. So we put the small particle on a substrate (we used a ferrocene). Then we can grow that fiber as you can see on the screen (figure 4). As a result we got this very nice fiber. From an academic point of view, it was a full success because I was able to grow the fiber, to reproduce the product (there were many observations of such fibers but nobody could reproduce them). I clarified the growth mechanism – that the small iron particle acted as a catalyst for the decomposition of hydrocarbon, that the thin hollow tube grew then thickens to a carbon fiber. As a result we got a fiber with a diameter similar to that of the PAN fibers prepared by Toray.

Figure 4. Endo’s vapor grown carbon fibers

Courtesy of Morinobu Endo.

BBV : Did you collaborate with industry in these years ?

ME : Yes we had collaborations. Showa Denko tried to develop this VGCF. But its productivity was very low. Because we put a substrate the growth rate was too slow. We tried to reduce the cost by using a continuous process. But in the same period the cost of the PAN fibers was drastically reduced so that we could not compete. Our VGCF are just beautiful fibers.

There had to be a breakthrough.

BBV : What kind of breakthrough ?

ME : I developed another method. This is the Endo-Japanese patent. I introduced the catalytic particles, which are derived from organic-metallic compounds such as ferrocene, into the reactor, in the three dimensions. The main difference is that there is no substrate. Here in this region, the particle reacts with the hydrocarbon and makes the hollow tube (figure 5). On the hollow tube then the deposition takes place. The process is in hysteresis. As a result we can get another type of fiber. It is totally different. This one is very competitve and commercialized.

I should add that at the early stage of the growth of the fiber, this is a carbon nanotube grown by a catalytic process. So it is now possible to grow carbon nanotubes by this method.

Figure 5. The Endo-Japanese patent, 1987

Courtesy of Morinobu Endo.

BBV : So you have already answered my next question : “How did you move from carbon fibers to carbon nanotubes ?” In fact, you prepared carbon nanotubes before this name came into use.

ME : We used to say “hollow core”. I get a little bit irritated about how the story is told. Here are my laboratory notebooks written in France (1974-75). Agnès Oberlin signed them. You can see a two-layered carbon nanotube. This is the TEM (Transmission Electron Microscope) photograph. I envisaged the possibility of very thin carbon nanotubes. Here you can read “mince cylindres” (thin cylinders). We had found the possibility of very tiny tubular structures.

BBV : Why did Mrs Oberlin signed this notebook in 2002 ? Was there a priority controversy ?

ME : Because I visited her in France last June. And because people said you should get the evidence that you had observed such nanotubes in 1975.

BBV : So nanotube was not discovered in 1991 by S. Iijima in his paper in Nature as people usually say..

ME : People say that Iijima clarified the structure of nanotubes. But Endo observed them in 1974. This is a recent understanding. I clarified the growth mechanism and the mass-production of a thick fiber out of a very thin cylinder.

BBV : The irony is that I came in touch with you through MIT thanks to Millie Dresselhaus and not through your French connection although I live in France.

ME : Mrs Oberlin lives near Montpellier in a mountainous area. She is now 75 year old. She gave me many evidences that I observed nanotubes in 1975.

BBV : Do you also know Bernier in Montpellier ?

ME : I know him but I am not as friendly with him as with Mrs Oberlin. He is a newcomer in science while I have been in carbon science for 30 years.

In my process the carbon nanotube is essential to grow the fiber but we can easily extrude the carbon nanotube. Now we can easily expand the technology to make carbon nanotubes. Several companies such as Showa Denko manufacture carbon nanotubes based on my method. Recently in order to make electronic circuit with carbon nanotubes people used this catalytic process. They put the small particle of iron on the electrode and expose this substrate to hydrocarbon to grow the nanotube. Here is a nanotube paper I am not too happy with ; they don’t cite my old paper. Many people are not fair. They only take into account recent science and never go back to older papers…

Anyway this catalytic process is now applied in the mass-production of carbon nanotubes, whether they have single wall or double wall. To me it is very important to produce carbon nanotube and use them for practical applications. So coming back to your question about the date of discovery of nanotubes : in 1975 there was no practical use of carbon nanotubes. The interest was in carbon fibers. So we designed a process to get a thicker fiber.

BBV : When did the interest shift from fibers to nanotubes ?

ME : Carbon nanotubes quickly developed after the discovery of C60 in 1985. But they still have no practical application because they are still high cost. For carbon fibers, by contrast, we already had the technology, the know how to produce them. However my nanotubes are already commercialized for Lithium ion batteries since the late 1980s (figure 6). It is useful to provide safe small-size batteries for mobiles and camcorders. For safety reasons it is better to use only Li+ instead of metallic lithium. For this, we need to intercalate carbon at the anode. Almost most of the Lithium ion batteries manufactured in this country use my fiber in the anode. It is the only material that can work in this application. There is no alternative, no substitutional material. Only my product. So finally what the Japanese companies produce is based on my carbon nanotube.

Figure 6. Mass-producing and commercializing Multi-wall carbon nanotubes since 1988

Courtesy of Morinobu Endo.

BBV : Which Japanese companies manufacture the Li-ion batteries with your patent ?

EM : Many companies (Sony, etc). But, now this is not my patent. It is the company who manufactures my fiber who owns the patent. Only the production system is my patent. And I am happy with that. Even French companies like Alcatel who have a battery division need to use my fiber. Recently we got the allowance to export this material abroad. The Ministry of Industry (MITI) gave us permission to export this material. Now Alcatel and a number of American companies can use my material.

BBV : Do you mean that a Japanese company cannot export one its products without permission from the Ministry of Industry ?

ME : It is only for strategic materials with potential military applications because it is a strategic material for military uses (although I don’t know which one). In such cases we are under the control of ICOCOM. Anywhere we can get such allowance.

BBV : Coming back to the earlier period of carbon science, what was your reaction and the reaction of your colleagues in 1985 to Curl’s, Smalley’s and Kroto’s paper on the fullerene structure ?

ME : I felt very nice because it was familiar to me. I was very excited with that kind of nanosize particles.

BBV : After this publication did you get more funds to start research programs on nanotechnologies ?

ME : There was an impulse to work on nanotechnology. And the government gave us substantial funds. 95% of the research budget went to nanotechnologies.

BBV : If you get such substantial funds from government do you also have support from industrial companies ?

ME : Most of my research is supported by industrial companies. Only a small part of the basic science is supported by MITI. For carbon nanotubes we work in close collaboration with industrial companies. We have a very nice cooperation. We are always aware of pratical purposes. So in my research science and applications are closely intertwinned. It is our policy.

BBV : But industrial companies have their own research laboratories ?

ME : Yes, we collaborate with them. Presently I have about 100 collaborators who run joint projects with me. More exactly, I should say 50 researchers who come to join me. It becomes big science when you want to reach the commercial applications because you have to do all kinds of tests : safetyness, production cost, optimizing the size, the diameter of the fiber, its packing...It requires a lot of time and a lot of money. The PAN-fiber, for instance, was designed in 1965 and Toray spent more than 20 years of R&D before the commercialization of PAN fibers in the early 1990s. For the batteries we took 7 years.

BBV : Do you have a kind of division of labor with Research conducted in academic laboratories and development in industrial laboratories ?

ME : We have a lot of feedback. For any specific material we need a lot of time and money. Carbon fibers still need a lot of additional technology for commercial mass-production.

BBV : So your financial resources come both from industry and from government ?

ME : Fortunately we get a lot of money from industry because I contributed a lot to industrial applications. We also get money from the Ministry of education for scientific development. I am acting as a bridge between science and industry, and also as an interprter for tax-payers. We do a lot of coordination with social demand, between university and industry and also of education for industry. We are very busy.

BBV : In your career is there a close connection between teaching and research ? In particular how important was the book on carbon that you co-authored with Stan Mrozowski and Millie Dresselhaus ?

ME I have been deeply encouraged by Millie Dresselhaus. Our book was not intended as a textbook. Rather it was a review book. When it was published in 1996 most of the people were rather interested in fullerenes. This book triggered the interest in nanotubes. The publisher Pergamon is very active in carbon science.

BBV : As historians of science and technology, we learn a lot from success but failures are even more illuminating for us. Would you tell mes about a case of failure in your career or in your field ?

ME : I don’t remember any project of mine which failed. I spend a lot of time selecting my research projects. It is important because lot of Japanese companies trust me. I have no right to fail. Every problem has a solution. In a sense the tiny cylinder of the nanotube is a miracle. How can we control particles at the nanosize !

Carbon is an old but new material. Professor Kroto who got the Nobel Prize in 1986 said in his Nobel address : the 21st century will be the century of carbon. I believe that. Carbon is a key material. Carbon fibers and carbon nanotubes are vital in three respects : for energy, fuel cells in particular ; for information technology (mobiles and computers) ; for environment, especially for the purification of air and water. The question of water is crucial : 2 million of people die every year from impure water and 20 million are sick from impure water.

BBV : How can you use carbon for the purification of water ?

ME : It is possible. We can use activated carbon to take off bacteria. Developing countries need clean water at a reasonable cost. So carbon is and will be in the future a key material. My own research is focussed on carbon nanotubes, their action, their preparation, growth mechanism, control of the structure and applications. We study batteries, new devices for energy storage in new cars, devices for water purification for the developing countries.

BBV : You mean that in one laboratory you can afford to conduct all these projects altogether ?

ME : Yes, as they are all related to carbon. Carbon and its properties are important everywhere. I’ll show you a very nice table. Carbon is not the most abundant on the earth like silicon. It is only 0.04% of the material resources. But carbon is localized, concentrated in some places so that it is easily accessible and easy to extract.

BBV : How many people are working in your laboratory ?

ME : I have 25 people including students and post-doc. We have ten research projects. They come from materials science, electronics or electrical engineering, physics and two post-doc chemists.

BBV : Do you have financial constraints for the purchase of laboratory equipment ?

ME : We have few constraints to buy instruments. For instance, we have got a very sophisticated Transmission electron microscope, all computerized (figure 7). It is a unique model made by a Japanese instrument maker. It has three functions : EDX (Energy-dispersive X-ray spectroscopy), EELS (Electron energy loss spectroscopy), and Mapping.

Figure 7. Endo’s Lab TEM

BBV : Did you acquire it with industrial funds or state money ?

ME : It was state money. We also have various analytic instruments for carbon materials such as STM (scanning tunnelling microscope), TGA (thermal gravimetric analysis), FE-SEM (Field emission scanning electron microscope), Thermal conductivity analyser, Raman, XRD (X-ray diffraction), pore distribution analyser, etc.

BBV : Do you have a lot of routine reporting to your sponsors ?

ME : We have obligations towards the university. The annual report mentions how much money I get from the Ministry of Education. But how much support I get from industry this is included in the global amount of subsidies provided to the university. The annual report does not mention openly how much Endo gets from industry. I think I am one of the most funded.

BBV : Publishing or patenting ? What is the priority ? Which one is the most important for the credit and reputation of a laboratory in materials research in this country ?

ME : It is now the Japanese policy that patenting and publishing should run parallel. For me publication is more important. But as part of the national community I should keep a balance between publications and patents. The Ministry of Education recognizes and rewards patents.

BBV : Do you file patents in your own name ?

ME : It depends. If the research project was financed with state money as a national project, then the patent is a state patent. If the patent comes out of a project financed by industry or by the university then it is your individual patent.

BBV : Who gets the royalties ? you or the university ?

ME : We have a judge who decides. If we invent a product with funds from the unviersity, most of the time it belongs to ourselves.

BBV : The patent on vapor deposition carbon fiber belongs to yourself ?

ME : Yes it is my patent.

BBV : Do you have international collaborations : in which countries ? How much do they matter ?

ME : With Millie Dresselhaus, it is a private collaboration. I also have collaborations with Sussex University (U.K.) and with Mexico. In France I have friends but no more collaborations.

BBV : Did you notice differences in the research styles of various countries ?

ME : I cannot see any difference in research styles. The Japanese style is very much americanized. Or rather, our style is between the French and the American styles.

BBV : What is the French style ? And how would you characterize the American style ?

ME : American style is top-down with the state at the top. French style is rather bottom-up. In Japan it is half-half. I feel rather close to the French style but for patenting we are more like the USA. In France it is difficult to file a patent.

BBV : You have spent 30 years on one single material, carbon. But do you think that the materials generic perspective with its basic notion of structure, properties, performances and process, is useful for your research ?

ME : I think that I have a very general concept of carbon. I generalized the concept from structures to properties. Process is very important to get up with the structure in the case of carbon. Carbon science developed by studying its structures but now processing is important. You get different structures with different processes.

BBV : What aspect is the more important for you ?

ME : I am neither a specialist in processing, nor a specialist of structures. I am a carbon scientist.

BBV : What is the place of materials science in general and carbon science in particular in Japan ?

ME : Unfortunately carbon is a minor field. Semiconductor is the major field. In the minor field of carbon I should say I am number 1 or number 2.

BBV : Does carbon science attract students ?

ME : Yes many students come to work with me, because we have advanced equipment and there are job opportunities in this country : in car companies or electric companies.

BBV : Where do you locate the leading centers in the field of carbon science ?

ME : The major countries are Japan, USA, France and Germany. Then come India, then China, England and Canada.

BBV : Do you see Japan as the leader ?

No. Japan, USA, France and Germany are at the front. It depends on the field. Certainly Japan produces 70% of the carbon fibers by the aerospace applications in the USA.

BBV : Where do you locate the strengths and weaknesses of Japan ?

ME : The human network is too strong. More open competition like in the USA would be necessary. In France the system is too centralized, too concentrated.

Fin de l’enregistrement

Pour citer l’entretien :

« Entretien avec Morinobu Endo », par Bernadette Bensaude-Vincent, 26 août 2002, Sciences : histoire orale,

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