Technology Spain , Madrid, Tuesday, June 02 of 2015, 14:58

“Calcium batteries might be more powerful than lithium batteries”

Interview with Jean-Yves Sánchez

UC3M/DICYT Jean-Yves Sánchez researches the development of calcium batteries that can compete with lithium batteries. He is carrying out the study under the auspices of CONEX, a talent attraction program that hires experienced international researchers. The program is funded by Universidad Carlos III de Madrid (UC3M), the European Union (Marie Curie actions from the “People” programme of the Seventh Framework Programme), the Ministry of the Economy and Competitiveness and the Banco Santander. The author of more than 140 scientific articles and 43 international patents, he has advised 32 doctoral theses and led three European projects and over a dozen national and regional projects in the field of electrochemical energy.


What does your research project consist of?

The ACABA (Advanced Calcium Batteries) project is creating calcium batteries that can compete with lithium batteries. To do this, we are trying to keep Spanish and French laboratories working closely together. The project adapts to the current challenges posed by the administration of clean energy and its storage.

But aren’t calcium batteries already on the market?

Yes, there are calcium batteries, but they are not rechargeable. The goal of the ACABA project is precisely to create a calcium battery that can easily be recharged.


What is the problem with conventional batteries?

Lithium-ion batteries are at present the main electrochemical storage systems in electronic devices and in the growing field of transportation. However, sources of lithium are limited and located in politically conflictive areas. Also, its cost is expected to rise with the increase in the number of batteries on the market. That’s why it’s necessary to seek alternative systems.


What advantages do calcium batteries have?

Up to now, calcium batteries haven’t been considered. However, the wide availability of calcium, its power and its redox potential make them promising candidates. Also, their power is similar to or even greater than the power of lithium batteries.


What is redox potential?

It is the electrochemical potential of oxidation-reduction. For a redox reaction to exist, there must be one element that transfers electrons and another one that accepts them. In the case of calcium, the standard potential of calcium is Ca => Ca2+ + 2 e- is close to– 2,8 V vs ESH.


What is needed to make a calcium battery?

You only need some negative electrodes, positive electrodes and calcium salts. Calcium, in its ionic form, is the fifth most abundant element and the third most abundant metal in the earth’s crust, in calcium carbonate, or gypsum, for example. It is also dissolved in the sea and it is inside our organism, in our bones.


What applications could these calcium batteries have?

They could be used in the same way that lithium-ion batteries are used—that is, in the automobile industry, in electronics and Smart Phones, in stationary batteries in Smart Grids, in uninterruptible power supplies, etc.


What other kinds of alternative batteries are being developed?

Internationally, there are many laboratories that are searching for alternatives to lithium-ion batteries. For example, sodium batteries have been known for about 40 years, but researchers are looking into the subject. There are other interesting options, too, like magnesium batteries or the research about new electrolytes that Toyota is carrying out.


What methodology are you considering for your research?

The first thing is to develop new liquid polymer electrolytes to obtain a good interface with the metallic calcium which allows a reversible functioning of this electrode. If it can’t be done, we’ll go back to other alternatives for the negative electrode. In fact, I’ve already made a proposal to the French National Research Agency (ANR, as it is initialled in French), and it has made it past the first selection phase. The project is called “Pioneering Calcium Batteries,” and I have involved UC3M in this work.


Which UC3M researchers do you collaborate with?

At present, I work most of all with Professor Alejandro Várez Alvarez’s team (Alvarez is head of the Department of Materials Science and Engineering and Chemical Engineering at UC3M). I also work with Professor Juan Baselga (he is also a professor in this department) through a European Marie Curie project that I am proposing. The university is striving to improve its level of research through the CONEX and Cátedra de Excelencia programs.


What is the most difficult in assuming this challenge?

In this particular case, we need to work in a very anhydrous place. We still don’t have a dry box, and if we buy one, there’s no place to put it in the laboratories.


What does researching at the UC3M bring you?

It is a change with regard to doing it in France. There I was occupying a chair as a professor of exceptional class at the Grenoble Technical College and I directed a group of about 24 researchers. Six of them were permanent staff. In Spain, the structure of research is very different. The Department of Materials Science and Engineering and Chemical Engineering, where there are researchers of different specializations, is partial to important collaborations in a field where you need a lot of abilities.


It seems to be an expanding field.

The subject of materials for energy is very important in Europe and all over the world, and I believe its funding will increase every year. UC3M has the potential to take a position of excellence in Europe and that is one of my ambitions. But if we don’t have more space and more safety in the laboratories, we won’t be able to achieve it.


If those problems are fixed, when could they have that calcium battery?

If it’s a battery with good benefits, I believe we could have one within three years. If we are talking about batteries that are rechargeable, I would say that we could have a prototype in three or four years, but with a positive electrode that is an alternative to metallic calcium.