Interview of Michel Armand,
conducted by Hervé Arribart and Bernadette Bensaude-Vincent,
in Paris, September 18, 2001
Michel Armand : Just to introduce my career, devoted to solid state chemistry, I would remind you that in France we have a special educational system with universities on the one hand, and the competitive grandes ecoles on the other. I came from one of these schools, the Ecole normale supérieure de Saint Cloud, where most of the students were meant to go all the way through the system. I chose to go into research. Graduating after 4 years, I applied for a student fellowship to study in the US. When I obtained a Fulbright fellowship, I went to Stanford . My supervisor was Robert Huggins and one of his post-docs was Stan Whittingham. In fact I left before submitting my PhD because I wanted to choose a research topic, namely intercalation compounds and solid-state batteries. My advisor wanted me to work on crystals and bronzes which effectively are very nice-looking but without interest for me. So I returned to France in 1972. I joined the CNRS shortly after, in 1974. The CNRS did not bother me when I did not publish for 5 years and let me supervise students before defending my thesis. I benefitted from great tolerance all through my career. I have far less publications than patents: 80 approximately. I have been on leave from the CNRS for the past 5 years while being associated with the Université de Montréal.
Bernadette Bensaude-Vincent How did you get into intercalation chemistry?
Michel Armand: Insertion or intercalation, that was the subject of my thesis. I had envisaged titanium disulfide (TiS2) as a potential candidate for intercalation but it was too expensive, too rare, so I dropped it. My doctoral research mainly consisted in trying several simple molecules as potential electrode materials.
Insertion chemistry has been developed in France by Jean Rouxel. He supervised a number of doctoral students who inserted metallic ions into various compounds but he never envisaged the electrochemical applications of this kind of compounds. Il dirigeait un certain nombre de thésards qui rentraient des ions métalliques dans des composés mais il n'avait pas envisagé les applications électrochimiques de ce genre de composés. De même à Nancy, Erold travaillait sur des composés d'insertion dans le graphite mais sans penser aux applications.
The first steps into intercalation of graphite were made in Germany in the 1830s by a German chemist. The ionic compounds were discovered by Faraday. He demonstrated that silver sulfide behaves as an ionic conductor. Bronzes with their beautiful rainbow colors were also known in the nineteenth century. Nineteenth-century chemistry was something fabulous. However since organic chemistry captured the attention of most chemists, they did not exploit conductivity. Moreover Dalton had won over Berthollet. They mainly considered stoichiometric compounds, and inorganic non-stochimetric compounds were ignored. Intercalation compounds prove that Berthollet was right. English chemists name them berthollides. They had only one application in the nineteenth century : it was the famous Nernst's glower. It was a commercial success. Doped zirconia is still an interesting material. One more illustration of the well-known law : on commence toujours par tomber sur le bon modèle.
Hervé Arribart: How did you begin with polymer electrolytes?
Michel Armand : The best way to use intercalation compounds was to use a soft electrolyte. I mean the electrolytes known at that time like silver compounds and beta-alumina were not suitable because their volume changed and you cannot maintain a good interface. Plastic materials seem more suitable. So it was mainly out of pragmatic motivations that I turned my attention to polymer electrolytes.
Hervé Arribart : At that time intercalation compounds had been studied for about 10 years. Did you participate in this development?
Michel Armand: In the 1970s two schools were concerned with intercalation compounds in France because solid state chemistry was well developed in this country. One was with Professor Erold in Nancy who studied graphite intercalation compounds. The other was Professor Rouxel's. They worked on TiS2,.... and selenides and all these well-known dichalcogenides...So the chemistry was known. But nobody had thought of using intercalation compounds as electrode materials.
In 1970, Stan Whittingham was a post-doc with Bob Huggins at Stanford. He was using bronzes to make measurements of the conductivity of beta-alumina. And they were making good contacts and observing the passage of ions between the two compounds because they were non-stochiometric compounds. But there was no concept of using this compound as a source of ions for storing energy.
It emerged in fact in 1972. It was during a NATO conference held at Belgirate in Italy where Brian Steele suggested TiS2, what he called solid-solution electrode and suggested its possible use as an electrode material. At the same time, my own presentation was dealing with graphite intercalation compounds. After that, the field almost exploded. I mean there was an explosion of scientific publications, because first, Stan Whittingham became involved with Exxon in the program for making batteries using TiS2 as an electrode material. Second, the electrochemical community had realized the potential of these compounds. So there was an enormous activity around these compounds which peaked around let's say 1989.
Hervé Arribart : Would you say that the Belgirate conference was the first event? Who participated?
Michel Armand : You would find the major actors in solid state electrochemistry : Brian Steele, a well-known metallurgist, you had Bob Huggins, Stan Whittingham well-known for the intercalation compounds, Hagenmuller, Jean Rouxel, and the people working on beta-aluminas at that time with Wynn Jones and the people from Ford and from the British programme. The British Railway company was working in this field at that time. So this conference unfortunately the book is out of print - was the outset of the solid-state chemistry's large role in batteries. Formerly it was known that fuel cells used ceramic compounds but then intercalation compounds would also be used for batteries.
Hervé Arribart : Would you say that solid-state chemistry was a discipline in itself at that time? And which were the respective roles of American and European scientists?
Bernadette Bensaude-Vincent : Did you consider yourself as a member of the solid-state chemistry community?
Michel Armand : Yes, I was working in Grenoble, working in a laboratory which specialized in solid-state chemistry, spanning over high-temperature ceramics, beta-aluminas, interfacial phenomena: A quite well-known lababoratory. So I have been, I believe, soaked into this field at an early stage in my career. And also you have to say that there was a definite prominence of France in solid-state chemistry which still lasts although it is not as obvious as it used to be 15 years ago.
Hervé Arribart : This lab that you mentionned, its tradition was also in electrochemistry?
Michel Armand : It was devoted to all aspects of solid-state electrochemistry. It was unique, having a big team of about 40 people solely working on solid state electrochemistry.
Bernadette Bensaude-Vincent : What was the name of the lab ?
Michel Armand : At that time it was laboratoire d' ionique des solides. The name was changed when it merged with other laboratories. But at that time it was mainly a solid state laboratory partly working on liquid electrolytes. They were precursors in organic electrolytes.
Back to Belgirate: suddenly the people in electrochemistry could benefit from the knowledge on intercalation compounds. I mean the chemistry of intercalation compounds : the crystallography, interpreting structure. This allowed a rapid progress.
Hervé Arribart : Could you say more about the French solid-state chemistry schools?
Michel Armand : In Grenoble there was a tradition of electrochemistry dating back to the nineteenth century. It is an heritage. There is a school of engineering there because there is a need for electrochemists. There was this group which sort of nucleated around Professor Desportes and developed research on high temperature ceramics and spread into all aspects of solid-state conductors, mixed conductors, ionic conductors: oxides, glasses, silver compounds, and so there was a common attitude which was more pragmatic than that of other groups.
Hervé Arribart : What was the status of Solid-State Chemistry in the USA?
It was mainly pragmatic. It was part of Materials Science departments. There was no per se solid state chemistry groups. When I moved to Stanford, Bob Huggins was in a Materials Science department.
There was a strong tradition of solid-state electrochemistry in the USSR. And our lab had strong bonds with laboratories in Moscow working on high-temperature fuel cells and also electrodes for MHD (magneto-hydrodynamics), a possible source for transforming fossil fuels into energy.
Hervé Arribart : Your own background was not in organic chemistry. How did you get this idea of polymer electrolytes?
Polymer electrolytes emerged from the fact that we needed soft electrolytes for using intercalation compounds. I had no knowledge myself of what a polymer was. I thought that polymers were a perfectly disordered state of matter that they could turn into a glass. On the other hand, the electrochemical community had also missed the fact that soft matter deserved some attention. Solid state electrochemistry was inorganic chemistry. Bridging the gap took at least 5 years.
Hervé Arribart : What was the role of Peter Wright, the British polymerist?
Michel Armand : Oh he deserves credit for having made officially the first polymer electrolyte. He realized that dissolving sodium or lithium salts in poly-ethylene oxide (PEO) which at that time was used as an additive for inks or for enhancing the viscosity of water. He realized that if you make complexes and if you heat this complex it becomes conductive. But what he did not realize, because of the gap between polymer chemistry and electrochemistry, was that such complexes had an enormous potential for making batteries when working in conjunction with intercalation compounds.
So when I started myself to consider PEO as a solid electrolyte, while I was in Stanford, I had not heard of Wright's paper. It was natural to think of polymers because the problem was the variation in the volume of the electrolyte. I called a colleague of mine in Grenoble to ask him which macromolecule could be used. He mentioned PEO. I ordered it. I mixed it with lithium bromide, I measured the conductivity. Nothing. I dropped the subject. Later when I read Wright's paper in 1975, I understood that I had lacked intuition. Had I heated above 50°C, I would have observed conductivity.
When I saw Peter Wright's paper I thought he had found the compound. Now it has to be generalized. So what was lacking was 1) were these coumponds any real conductors; 2) could they be made for the metal whose intercalation chemistry was prevalent, i.e. lithium. This was very rapidly approved. There was this presentation in St Andrews and people jumped into the field from both sides: electrochemists started making or buying polymers or and polymer chemists started measuring conductivities.
Hervé Arribart: It seems that understanding the mechanisms of conductivity in polymer proved to be difficult.
Michel Armand : Oh yes. The theories were there but there was no common application. The polymerists were well aware that thediffusion or transport of material in an amorphous structure was obeying a special law which was called the free volume law. Polymer chemists knew a theory first proposed in the twenties or the thirties which pointed to a temperature which plays the crucial role from a thermodynamical point of view: the glass transition temperature which determines everything. In solid state electrochemistry, the classical Arrhenius law was obeyed most of the time. In fact if you look after 20 years you realize that the situation is not so simple that in some polymers Arrhenius law was sometines obeyed, and that in very high temperature beta-alumina the free volume is sometimes interfering.
Hervé Arribart : Were there colleagues of yours in Grenoble working on amorphous solids? Did it help you?
We had good relationships, scientific discussions about the discrepancies between glasses and polymers. Discrepancies and also frustration because the best conductors not especially for lithium are glasses, compounds which are brittle, hard and in which you imagine that it would be more difficult for ions to crawl than in soft matter like polymers. And to our surprise polymers were very good conductors at 60-80°C, warm, lukewarm temperatures. At room temperature conductivity dropped to almost insulators while glasses remained conductors. This situation has been kept for almost 25 years. Trying to break the tg barrier to avoid having a drop of conductivity barrier when you get close to the glass transition temperature of soft matter of activation energy has been the main challenge of research.
Hervé Arribart : When you started to have contacts with industrial companies did you get into trouble with the CNRS. How did you arrange the contracts?
Michel Armand: As soon as we made the first polymer battery and realized its potential we applied for a patent through the CNRS. We did not realize that the patent filing was delayed a couple of days after the presentation in St Andrews. For us it was not very important because in a naive belief we thought that if you speak publicly you may not have your idea stolen from you. But in fact no, according to the French law, if you disclose your invention it is no longer patentable. In the US you are supposed to be able to disclose your invention and you have ten years to file your patent. You are protected because you are the inventor. But stupidly enough because we did not realize, not knowing the law, the patent was extended one year after its filing date and not the date of the St Andrews presentation. In fact the patent was not cancelled but a number of our claims were withdrawn.
Surprisingly, it was possible to keep most of the claims in the European litigation but a re-issue was asked at the patent office in the US. It became a nightmare. I will be very frank and provocative in saying that the US patent office displayed a kind of protectionism : the file was lost two times, the examinor was changed many times. We finally ended up sending a lawyer especially to discuss with the examinor and he said that it was absolutely obvious that the examination should have been made before and so on. Finally the patent was re-issued with one claim just one year before the end of its life.
In anycase this did not deter Elf Aquitaine to start doing common research on this subject. At this time, oil companies were trying to diversify their activity, -solar energy and so on - trying to have a green image. For a while we worked together and we were joined very rapidly by Morselus Contender which was the electricity utility of Hydro-Quebec which is like PTNE or in the US, Edison or like EDF in France. This company mostly relies on hydro-electric power with a lot of hydro-electric possibilities. The cheapest electricity in the world is in Quebec. And they were interested in my goal, my dream: having an electric car, for pollution reasons.
Bernadette Bensaude-Vincent: Which were the terms of the collaboration between Hydro-Quebec, Elf-Aquitaine and the CNRS?
Michel Armand : This is also a subject of controversy. I will be very frank. The CNRS did something that it would not do anymore because it has learnt the lesson. It gave the property of the patent to Elf-Aquitaine who then sold back 50% of the co-property to Hydro-Quebec. In this sense, I think that whatever the country where I work, the state research bodies NSF or CNRS or any other agency should never give up patent property. This was the cause of many troubles because it gave Elf Aquitaine complete power over the future of the project.
Bernadette Bensaude-Vincent : What was the reaction of the CNRS when Elf sold its part of the project?
Michel Armand : CNRS could not object because they had made this mistake of giving the property of patent instead of giving the license. Which should never be the case. The governement should always be in a position to make the best use of the research which uses tax money. It should be in control of the output of public research.
Bernadette Bensaude-Vincent : Why did you chose to work in Montreal instead of staying in Grenoble?
Michel Armand : It was supposed to be for one year. And we felt five years ago that we were in the final part of the race. A start-up company was making prototypes. The USABC, United State Advanced Battery Consortium, made the choice to invest heavily in solid state batteries. So I thought that it would be easier to work in Montreal than crossing the Atlantic four times a year.
Hervé Arribart: You mentioned the role of electric vehicle in your research program. How would you characterize the role of state programs? And the private programs conducted by automobile companies.
Michel Armand : In the early eighties there was no serious program in electric cars. There was a small activity. People were interested but they did not believe that the electric vehicle would be emblematic (?) before the mid twenty-first century.
Bernadette Bensaude-Vincent : What was the role of EDF (Electricité de France)?
They were not interested, in the assumption that nuclear power was so abundant that they would not need it. They did not have the expertise : they needed to work in the field of batteries. They left this role to companies such as CGE (Compagnie Générale d'Electricité). They were certainly interested in batteries for load-leveling but they did not invest into batteries which seemed in any case too far away from applications.
The people in charge of developing companies were CGE in France or Duracell in the US or whatever battery companies. People did not realize that the solid-state polymer battery is completely different from conventional batteries in terms of technology: it's more akin to paper mill, or printing technology : we are speaking about thin films, and high speed. Solid state polymer batteries have a high surface, thin film configuration. Inspiration and information came from the paper and the film technologies or printing technology.
Batteries and fuel cells are still some of the best for producing electricity locally as a co-generator. Intercalation compounds are used for portable items.
Hervé Arribart : After 30 years what is your feeling about the role of Solid State Ionics?.
Michel Armand : Its importance has been reinforced recently by the concern for batteries and fuel cells. Most of the driving forces for Solid State chemistry were in the field of energy, the batteries and the fuel cells.
Hervé Arribart : How do you see the future ?
Michel Armand : The future? We need to use energy more efficiently, to reduce pollution .... Definitely the near future will be hybrid cars in which we decrease by a factor 2 or possibly 3 the consumption of the car by coupling a normal internal combustion engine well attuned for working at its maximum efficiency with batteries. The batteries are here to provide power for acceleration and also to absorb power every time you break. That way you make better use of your fossil fuel. This is what Japanese car makers Toyota and Honda are going to commercialize. These companies are losing on these cars but they were overwhelmed by the demand. People creating these hybrid cars are so enthusiastric about the feeling of a soft ride, almost noiseless, and low consumption. Taxi companies in Lausanne are among the first.
There is also a niche for truly electric cars. Solid-state batteries are ready. If our informations are good there will be solid-state batteries at the Hydro-Quebec ??? company will be available to be tested by the public at the next electrical vehicle (EV) meeting in Montreal next month. This car can be driven for 200 or 300 km on a single charge which makes it suitable for daily commuters, especially for people with a recharging facility in their garage. These cars are ready and it is just a question of political will. On the other hand, there is definitely some lobbying from oil companies, and car companies are not yet willing to change their habits. They are going to sub-contract the making of electronics for EV, the batteries for the electric motor. So they are going to have a less dominating role in the making of the cars. There is some resistance against such a change. Now that the California law has been passed prescribing 10% of the new vehicles with 0% emission hybrid cars are taken seriously unlike in the eighties. They still have to reach political acceptance.
Hervé Arribart : Beta-aluminas have been considered as model-materials and they prompted industrial developments. Do you consider that there is a future for this material?
Michel Armand: The sodium-sulfur batteries produced by Zebra companies have demonstrated their ability to be used for the EV. It's a question of price. There was also a concern for safety becasue we are speaking of batteries operating at 300°C but most of these issues have been addressed. The main problem is the cost. It makes sense to work on this Zebra batteries for load-leveling. This battery has an almost endless life. In this case the investment can reach very high levels because there will be a return of investment over 10 to 20 years. So the price is less drastic than for a car whose lifetime is 5 to 7 years depending on the countries. And polymer batteries working betwen 60 and 80°C are very easy to manage. I believe that 20$ per KW/h for stored energy can be made with a polymer battery because the technology is different from that of conventional batteries. They can be made with a very high volume of production, high speed, high conductivity. The same way paper is not expensive although the machinery used to make paper is extremely expensive. The productivity is enormous. Polymer batteries have the same characteristics.
Bernadette Bensaude-Vincent : The EV is your dream. What attempts did you make to convince and get support from state agencies and car companies?
Michel Armand : There are 3 stages : research, R&D and development. I never had problems at the research level. This was science, we had the CNRS resources. We were lucky in having Hydro-Quebec joining the research team. Michel Gauthier who was the head of the research group in Hydro-Quebec convinced this company to invest heavily in R&D. Several millions of dollars a year for R&D invested in long-tem research. By contrast the investment by oil-companies was only superficial. That is why Elf sold the project to a Japanese company who did not contribute to its advance.
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This page was last updated on 3 April 2001 by Arne Hessenbruch.