Australian Academy of Science – Science education Interview with Professor Maria Skyllas-Kazacos

Professor Maria Skyllas-Kazacos, chemical engineer, was interviewed for the Australian Academy of Science's  Interviews with Australian scientists  program in 2000. The interview was conducted by Ms Claire Hooker. Here is an edited transcript.

I myself started off with the aluminium and the molten salt work, but I was offering honours projects in solar energy and some battery topics as well. By about 1984 I had a couple of PhD students who were being funded by Comalco, an aluminium company. One of our technical officers in the school was trying to finish his degree in electrical engineering and had chosen a masters project to look at the storage of solar energy. Professor Martin Green, in the Solar Energy Department, told him, ‘I can’t supervise you in that area, but if you can find someone else to co-supervise you, then I’ll be happy to take that project on.’ Knowing that I was an electrochemist and energy storage is one of the areas of electrochemistry, he asked me if I wouldn’t mind co-supervising him. He had been reading about NASA’s work on redox flow cells, and he wanted to work on the iron–chromium redox battery which NASA had started working on. I started reading about that project and found it really interesting, so I agreed to supervise him. And that’s when I began to get involved in this area of energy storage research.

As he got further into the project, it became apparent that this system was not going to go very far. Because of various inherent problems, it was leading to a dead-end. Although the redox flow battery concept was ideal, one problem was that if you have two solutions of different elements separated by a membrane, when you pump the solutions through the cell stack the membrane can’t separate them permanently. No membrane is 100 per cent efficient: eventually you get the solutions permeating through the membrane and mixing, and you end up with two fully mixed solutions which you have to take out or re-process or just replace. It was obvious that we had to find something to overcome that problem and only an element which had different oxidation states could work. So we started talking with various people about a number of different elements.

Vanadium oxidation reduction: a puzzling experimental hitch

Vanadium is the obvious element – everyone knows that vanadium exists in different oxidation states – and a few other elements could work, such as tungsten, molybdenum and titanium. Professor Bob Robins had suggested that we try vanadium first, as he had been doing some research on its extraction for a minerals processing project. I decided to give vanadium a try but we hadn’t done any previous work on it, so we thought we’d apply for a grant to see if it would work. We didn’t get the grant but I was very keen to see if it was going to work anyway, and the next year I managed to get an honours project student, Elaine Sum, onto this project. In fact, she was the top student of the year, getting a university medal.

I started to get her working on different vanadium compounds and electrolyte solutions, but after a lot of trials, she could not observe any reaction. It was discouraging. But I’m the sort of person who, before I give a student a project, wants to make sure it works. So during the Christmas holiday I’d actually tried the experiment and found that it did work, but then every time she tried it, it just would not work. We went backwards and forwards in the laboratory, and finally we worked out that whereas I was doing quick, rough experiments and it was working, when she was doing things very meticulously and cleanly there were no reactions. We discovered that the key to the whole thing was the way I was scraping the electrode, which had to be roughened up to activate it.

After many years of studying all the mechanisms, and why and how things work, we now know that if you use carbon as the electrode for vanadium – which is what we were trying to do – the vanadium oxidation reduction reaction involves not only a transfer of an electron but a transfer of oxygen as well. The VO²⁺ has to gain an oxygen to go to VO₂⁺, and if the carbon is too clean there aren’t any oxygen groups on the surface to allow it to grab an oxygen. Consequently it wasn’t reacting on the clean, smooth surface.

Vanadium systems: paradoxes and challenges

I have the impression from Dr Bhathal’s interview with you that there was absolutely no reason why you should have continued working on vanadium. Apparently it didn’t exist in a soluble form and from the literature you would never have predicted the results that you actually got. So what made you do it?

Well, initially you have an idea, and then of course you go to the literature to make sure that no-one else has done it before or, if it has been tried, what drawbacks and limitations there are. No-one had tried a vanadium redox battery before, but we needed to understand some of the fundamental properties of vanadium ions. The most important fundamental property of vanadium systems is that the ions must exist in highly soluble forms, because that’s how a redox flow battery works. When you charge it and discharge it, the ions have to be in solution. If they come out of solution, you’re in trouble.

So you have to check the solubilities. But often there’s not enough information on solubilities or it’s only in limited systems. You might find the solubility of vanadium in water is very low, but what if you use a different system? So you shouldn’t be turned off by what you initially read, because the literature that’s available often contains limited information and does not necessarily lead to a dead-end. There could be conditions in which all of the vanadium ions might show a reasonable sort of solubility.

When we first started looking at it, it appeared that all the oxidation states were okay except for the vanadium(V), which is extremely insoluble. We were simply hoping that we’d be able to find an electrolyte which would allow it to be dissolved in a high level, but no-one had shown or predicted that. There was nothing to actually lead us to such a conclusion; we were just hoping to find something. In fact, what we eventually discovered was that the common V(V) compounds are highly insoluble, but if we started off with the soluble V(IV) sulphate to produce a 2M V(IV) solution it was possible to charge it to the V(V) state without the V(V) coming out of solution. In fact, this turned out to be the vanadium redox battery invention and this was something that could not have been predicted. But again, it was necessary to find the right type of solution in which to dissolve the V(IV) so that we could oxidise it to V(V) as well as reduce it to V(III) and V(II).

And then you experimented with various forms and came up with the sulphuric acid?

That’s right. Vanadium is a really tricky system, a very complex element. That’s what makes it so fascinating. You could spend your whole life studying it and still not understand it. Each of its oxidation states has its own chemistry. Things behave in opposite directions. For example, if you try to increase the solubility of one ion, it then tends to reduce the solubility of one of the others. To get conditions which will allow all ions to exist at a relatively high solubility is very tricky. And then there are things like temperature. Typically, one would try increasing the temperature of the system, because all other ions will increase their solubility with temperature. But not vanadium(V). If you increase the temperature, vanadium(V) precipitates. So you’ve got to work within an operating window and try to find ways of extending it so that you can operate over greater temperature ranges. The same happens with the sulphuric acid. If you increase the concentration of sulphuric acid to get the vanadium(V) into solution, all the others start precipitating. Everything works against you. It’s a real challenge to get those conditions right so everything works together in your favour.

Cooperation, collaboration and research synergies

Have your relationships with your students been particularly important and sustaining in your research?

Having a good research team and good students is vital. You need their commitment to be able to get good progress. Fortunately, I’ve always had really good research students, who are also good researchers, as part of the group. I am still in touch with Elaine Sum, my honours student who did the first experiments on vanadium with me, for example. She stayed on to do a PhD with me on an aluminium electrolysis project, then took up a postdoctoral fellowship in the UK, went on to Germany and now is back working in the research laboratories of Comalco, in Melbourne.

After those preliminary vanadium studies with Elaine in the laboratory, we went on to reapply for the grant to investigate the vanadium battery. By then we had some evidence – it wasn’t purely speculative as it was in the first round of applications – and we were able to get the grant that second time. Once we were given the funding, I was able to employ a masters student and a research fellow, Dr Miran Rychick, who then came to join our group. With their input, we were able to prove the concept further and, at least in a small-scale cell, show that we were able to get really high efficiencies. That led to subsequent grants, allowing us to employ more people, enlarging the group. At one stage, by about 1987–88, we had about 18 group members in the laboratory, including my husband.

After my husband had taken that one year off to help to look after our son Anthony, he decided to do a part-time masters in electrochemical technology to retrain himself – he was getting really excited about the vanadium battery project and he wanted to be a part of it, but his background was not appropriate. After completing his masters, he started working in the laboratory on a voluntary basis with no pay. After a year or so of that, we applied together (successfully) for a few grants, and from there on he could be officially employed. Basically he was the project coordinator for many years, helping to coordinate the laboratory facilities and all the staff, and keeping things happening on a day-to-day basis.

Such an all-consuming project must have overtaken your other research projects.

Well, because we were very successful in getting grants to further develop the vanadium battery, for several years it occupied most of my research effort and I had to put my other research interests aside. But now that the vanadium battery has actually been bought out and taken over by a company, I’m a lot freer. A lot of the issues of commercialisation and manufacturing can be taken care of by other people, so I can now start thinking about other research areas as well.

On to methanol fuel cells, back to aluminium electrolysis

What research projects do you have in mind now?

Firstly, I’m interested in fuel cells. I like the idea of methanol fuel cells, so I’ve got a student working on direct methanol fuel cells. The ideal fuel cell is one where you feed hydrogen on one side and oxygen on the other, and they combine together electrochemically to produce power and water. But hydrogen is so difficult to store and to transport. So instead of using hydrogen directly, people have been working on transporting methanol and then feeding it into a pre-process to convert it into hydrogen. Then the hydrogen is fed into the fuel cell. This reforming process is very complex, like trying to get a chemical reactor happening in the fuel cell and hoping it is going to work optimally. I think that’s too ambitious. So researchers are now starting to look for suitable catalysts which will allow the methanol to directly react: feeding methanol into the fuel cell and reacting it with oxygen to produce electricity – and carbon dioxide and water, in this case.

Fuel cells lead to the possibility of clean sources of energy, because they don’t produce as much pollution as does burning the methanol and/or other fuels with oxygen, and they are more efficient. When you burn a fuel, the efficiencies are quite low, usually around 30 per cent. When you electrochemically react the fuel with oxygen, you can get more than 60 per cent energy efficiency. For the same amount of greenhouse gas – carbon dioxide – you’re producing twice as much energy. So fuel cells are very promising future alternative sources of energy. But they are alternative ways of generating electricity, not storing it. You can’t really use a fuel cell to store solar energy, and to use a fuel cell to generate hydrogen and then store the hydrogen is not very efficient. It’s still best to store energy with a battery.

Secondly, I’m interested in returning to aluminium electrolysis research. We’ve recently set up a new Centre for Electrochemical and Minerals Processing in our School of Chemical Engineering and Industrial Chemistry. In fact, Barry Welch has now retired from the University of Auckland and I’ve invited him back to our department as a Visiting Professor and as Associate Director in the new centre to work with us on aluminium projects.

Industry, applied science and pure research

As an applied scientist wanting to do research with implications for the real world, how do you see yourself in relation to so-called pure scientific research in Australia?

I’ve always felt the need to see an outcome to whatever I do, a purpose to my efforts. So when I start off on a project I want to see its purpose. But once you get into a project you find that the research becomes pure as you get into the complex experimental issues, and with the vanadium battery we had to do pure research as well as applied, in order to understand everything – why and how things happen. Without understanding it you can’t possibly do successful development, because you can’t improve things unless you know how they’re behaving and why. We’ve been fortunate that we’ve been able to do both pure research and development. Over the years we’ve had funding for the PhD students to do the pure research while some of our other research group members would do the development.

I have the best of both worlds, actually. I find more stimulation in doing research rather than development, but it has to have an outcome. I need to see that it could be important for something in the future. I also like to see a possible benefit to society.

Has working with industry partners on the vanadium battery been a good experience?

Initially we were mainly funded by government. In those days we could still get enough funding from various government sources to make reasonable progress in the research and development. But it was important to get industry interest in the project, otherwise it would not have had an application and would never have been able to get off the ground – and then the government would not have wanted to fund it.

Our development approach was influenced by the interactions we had with industry. Very early on, an Australian company took out a licence – international and exclusive, all round the world – to the technology. But although we believed that the vanadium concept had potential, a company needs some assurance that it is supporting more than scientific curiosity. It needs some prospect of commercial return, otherwise you can forget it. So the first problem we had to solve was how to get vanadium pentoxide into solution. It was simply uneconomical to start with vanadyl sulphate at a price of $800 per kilogram, so we had to develop very quickly a process to dissolve vanadium pentoxide and form an electrolyte. Once we did that, then we were at least confident, ‘Okay, this is going to be economically viable.’ That started me on the road to realising that in addition to the research we must always keep in mind economic issues such as the material’s availability, 'manufacturability', cost and other commercial considerations. The development part was really important.

Marketing the vanadium battery

Did you have to market the battery?

Oh yes. It was so funny, the way things turned out. Back in 1986–87, a small feature on the vanadium battery project was put into an issue of  Uniken, which tends to send some of its stories around to newspapers. The  Sydney Morning Herald  rang me up and then sent out a team to take photographs. We were waiting to see the newspaper the next day, expecting to see an item in the back pages of the ‘Higher Education Supplement’, but when my husband bought the newspaper next morning he came home saying, ‘Guess what. You’re on the front page.’ And there we were, with this little cell that was going to be 'groundbreaking', 'revolutionary' and all this. We thought, ‘Gee whiz! What have we created here?’

Another expectation to live up to!

Exactly. The TV and radio stations started ringing me up and there were more newspaper reports, and for the next several weeks it was one interview after the other. The head of school at the time came to see me one day and said, ‘Maria, it does work, doesn’t it?’ I said ‘Oh yes, it works.’ But that set the tone. We’d proven that we could get 90 per cent energy efficiency, yet it was just this little cell. From there we had to live up to the expectation that in the end we would deliver. It certainly led to a lot of commercial interest as people read the newspaper articles and heard me on radio, and people from different companies, institutions, organisations were ringing me up all the time, wanting to find out more about it.

The company to which we licensed the technology in 1987 was Agnew Clough Ltd: it owned vanadium mines in Western Australia so there was a common interest, a synergy. But sadly the person running the company had a heart attack and died, and then there was no champion, no driving force for the company’s involvement in developing the battery. For several years we just went along but with no real commercial direction, until the company felt it simply couldn’t continue to fund the research. It withdrew and returned the licence to the university – but signing an agreement to share in any profits made in the future, so it did actually get something back. So we were left stranded, having to continue to market the idea and find people interested in it.

Over the years, however, we always had media interest. Reporters would come back to get an update. We appeared on Quantum, The 7.30 Report, Beyond 2000 and so on, and were featured in newspaper articles. A lot of those reports appeared in other countries, and people overseas wanted to find out what was happening. Even though I was over here in Australia, because of the international interest that the project was generating I never felt isolated, at least in relation to the vanadium battery. People were always coming to us from all over the world to find out what we were doing and where we were and what was happening with the vanadium battery development.

Being equitable about gender equity

In an industry field such as yours, would you have many women colleagues?

Chemical engineering for the last 20 years has attracted a reasonable number of females as compared with other engineering disciplines. When I did it, there were two or three females in my class, but since I became a lecturer about a third of the students have been females. And that’s been fairly constant, whereas the other engineering disciplines have been struggling, starting off with almost zero and deliberately building up to 8, 9, 10 per cent through Women in Engineering type programs at both high school and university level.

Do you think women have mostly self-selected themselves out of those subjects, because they lack experience and exposure to them?

I think the culture has made them believe that women don’t want to do science and engineering. Therefore, they meet society’s expectations by deciding they won’t do science and engineering.

Did you feel like a pioneer?

Perhaps, but not at first. When I was choosing to do industrial chemistry or engineering I wasn’t even conscious that not too many women were doing it. I knew that most of my friends at the time were choosing very traditional things like teaching or whatever, but no-one made me feel as if I was being excluded at all from those areas. When I started at the university, though, it became obvious that it was a male dominated area. There were many occasions when I’d go to conferences as the only female in the whole auditorium. Then again, that makes you well known – everyone gets to know you really quickly.

What’s been concerning me over the last few years is the way that school educational policies have been trying to focus on girls, with an insistence that the poor girls have been excluded from maths and science because the boys have been dominating the class and haven’t allowed the girls to excel. I have been very sceptical, even cynical, about those theories and ideas. Basically women weren’t interested, okay? And that’s unfortunate: I used to love mathematics and I couldn’t understand why other people didn't. It’s important to give the information and expose male and female students to all their options, but not to try and bias the system. Over the years everything’s been biased towards the females, and I feel sorry for the boys now. I’m the mother of three sons, and I keep on telling them that because the system is geared to work against them they’ve got to be really careful to make sure as they grow up that the future doesn’t exclude them totally.

 

Maria with her family – Michael, Nicholas, Anthony and George.

From acknowledged achievements to a beckoning future

We have spoken about the prize you were given shortly after you returned to Australia. That’s a long time ago. What honours have you received in the meantime?

I was very honoured to be awarded, first of all, the Whiffen Medal, by the Institution of Chemical Engineers and the Institution of Engineers Australia. That is for applied research or projects with applications for industry. Then two years ago I was awarded the Chemeca Medal, the most prestigious chemical engineering award in Australia, again by the Institution of Engineers Australia and the Institution of Chemical Engineers. Both those medals were awarded for the vanadium battery. I was nominated for them by Mr Graeme Paul, who is a member of the RACI and a really wonderful person.

And in 1999, in the Australia Day honours – again on the nomination of Graeme Paul – I was made a Member of the Order of Australia. That was a great honour and a very proud moment for the whole family.

What are your ambitions for the future?

I want to continue the research I’m doing now. Mainly, though, I want to find more time to travel, because with young children I’ve always tried to restrict the amount of my travel. I get a lot of invitations to go overseas but most of the time I have to turn them down politely because I haven’t wanted to travel without my children. But as they’re growing up now and getting more independent, I’m hoping to start doing a lot more travelling, visiting overseas research laboratories and attending more international conferences – and, who knows, starting a whole lot of new things in the future with my husband.

Do you look forward to a time when you can limit administrative and teaching work in favour of research?

Actually, that is one thing I’m hoping to be able to do. I’m not yet sure how, but I’ve got a few thoughts about it. Hopefully, I’ll start taking study leave, which is another thing I haven’t been doing much of, and getting away for a while. While I have enjoyed teaching throughout my academic career, I'm finding now that it is just too difficult to do everything well. After another 5-6 years I hope to be just doing research and that will give me more time for travelling, and reading novels and resuming art and sketching and so on – all those other things that I’ve put aside for 25 years.