The Amiens start-up Tiamat develops and produces innovative batteries using sodium ions in a standard industrial format.
In addition to their specific performance, these batteries offer an alternative to lithium-ion technology, the production of which relies on critical materials due to their rarity and their geostrategic origin.
Coming from the French network on electrochemical energy storage (RS2E) supported by the CNRS, Tiamat now has several functional prototypes, and is currently working on the construction of a gigafactory on French soil in the years to come, to supply a European market that will grow strongly in the years to come.
Hervé Beuffe, President of Tiamat, explained to Techniques de l’Ingénieur what makes the specificity of sodium-ion technologies and of the Tiamat company.
Engineering Techniques: Tell us about Tiamat and the specificity of the sodium batteries you develop?
Herve Beuffe: We are developing a specific way to make sodium-ion batteries. As with lithium-ion batteries, there are several cathode chemistries in the sodium battery family, each with their own specificities. There are thus three different chemistries.
The first, PBAs (Prussian Blue Analogs) are inexpensive and readily available cathode materials. However, they are going to offer average battery performance. The second family of cathode chemistry, polyanionic materials, constitute the cathodes of our first generation of batteries, which are on the market today. These crystallographic compounds have a very high power density, which makes it possible to supply a large amount of current over a very short period of time. This allows, for example, to charge our generation 1 batteries in 10 minutes. With this generation of batteries, we are at an energy density that I would describe as average, around 100 Wh/kg.
What are the applications for these power batteries?
The applications for this type of power battery will be automotive hybridization, stationary power applications, support for hydrogen fuel cells, power tools, etc. Ultimately, this generation battery may be of interest to a set of fairly dispersed markets, but which ultimately represent a relatively large volume. Our ambition is to become the benchmark for power batteries. The material that we have developed for this application, the MVPF, is also patented, which allows us to be protected as to the specificity of our first generation batteries.
What are the materials that make up the third cathode chemistry of sodium batteries?
Lamellar compounds constitute the third category of materials used. They also concentrate a very large majority of current research and innovations. Our second generation battery, which we are developing alongside the first, works with these compounds. The ambition with this second generation of batteries is to approach the performance of LFP (lithium-iron-phosphate) batteries. Even to exceed them. It is not a power product like our first-generation battery, but a medium-density product, which can find outlets in the electric mobility sector, for example.
European ambitions in terms of battery production in the years to come are very high. How to meet this challenge?
In 2030, a study by McKinsey estimates that 4.7 TWh of annual battery manufacturing will be needed worldwide. These figures illustrate, among other things, the European desire to move towards electric mobility quickly, to meet climate challenges. To achieve this, material resources are lacking. By 2030, we will only have 50% of the lithium and nickel needed to achieve this goal. And 80% for cobalt. It is therefore essential to develop alternative solutions. The sodium-ion technologies that we are developing can make it possible to achieve this ambition of 4.7 TWH, in particular because we are already in the market entry phase.
What about recycling lithium batteries? Could it make it possible to avoid the pitfall of the lack of resources?
Not before 2030, that’s for sure. The first batteries to be recycled will be available in about five years, and they will represent only a tiny part of the needs at that time. Recycling will always be marginal compared to the use of new materials, it cannot be the solution to the problem. Even if it is of course necessary to recycle the batteries, it is today part of our mission, and it is essential. But this recycling mission needs to be unrelated to European battery production targets for 2030.
Can you explain to us the contours of the gigafactory project led by Tiamat?
We will have a factory at the end of 2025, which will have a capacity of 1 GW expandable to 5 GW and which will supply the European market with prismatic cells for markets that we have identified. We would like to set up this factory near our current location in Amiens. It so happens that many French players in the battery sector are located in the North, so there is an opportunity to develop a battery ecosystem in the region that would benefit the whole sector.
Interview by Pierre Thouverez