In an interview with Carly Weller, Sébastien Patoux, head of the Battery Technologies Division at The French Alternative Energies and Atomic Energy Commission (CEA), offered a glimpse into the organisation’s role in shaping France’s battery chemistry future.
With over 30 years of battery research under its belt, CEA stands as a linchpin in France’s energy transition – bridging fundamental science and industrial deployment across the entire battery value chain.
CEA’s battery division, headquartered in Grenoble with teams in other French centres, comprises around 300 researchers and engineers. “We have been involved in battery activity for more than 30 years,” Patoux explained. “We first started working on cathode materials, then on anodes and electrolytes, and started making small prototype cells in the late 90s.”
Since 2010, the organisation has scaled up its capabilities through a collaboration with Renault, filing over 700 patents and developing pilot manufacturing lines for lithium-ion cells. It continues to explore a range of chemistries and processes to advance its technology portfolio.
CEA’s remit spans the full battery lifecycle, from materials synthesis and cell design to battery management systems (BMS), recycling and second-life integration. “We are able to close the loop,” Patoux said. “We also carry out Life Cycle Assessment (LCA) and undertake multiscales and multiphysics modelling and characterisation activities to help improve our technologies.”
Chemistry diversification
On the cathode side, after working on various materials such as high voltage spinel oxides and lithium iron phosphate for 15 years (2000–2015), CEA is pushing the envelope with nickel-rich and manganese-rich NMC variants to boost energy density. “We’re working on combining cathodes with solid-state electrolytes to find the right recipe,” Patoux said. “But we’re also continuing to develop cathodes for conventional lithium-ion cells, mitigating performance, safety, cycle life and cost.”
Silicon anodes have been a long-standing area of expertise. “We have been working on silicon anodes since 2008,” he said, highlighting partnerships with Umicore and Syensqo (formerly Solvay) on materials development and hybrid polymer ‘gel’ electrolytes.
CEA’s commitment to sustainability extends beyond chemistry. The organisation is working with Orano on advanced recycling processes, including battery discharge, dismantling and materials recovery. “The goal is to recover battery systems already on the market and recycle them,” Patoux explained.
Repairability and modularity are also gaining traction. “Sometimes, only a single component needs replacing,” he said. “We aim for smart system integration that boosts energy density while allowing easy disassembly – so individual cells or modules can be swapped out when necessary.”
CEA’s collaboration with Taiwanese company ProLogium, which has plans for a gigafactory in northern France, exemplifies this system-level innovation. “We recently discussed how to achieve effective integration of solid-state cells involving a ‘design-for-disassembly’,” Patoux said.
Strategic alternatives
In a bid to reduce reliance on critical minerals such as lithium and cobalt, CEA is investing heavily in sodium-ion and potassium-ion technologies. “We’re fully prepared to advance sodium-ion technology,” Patoux said. “We were also involved in preliminary R&D work and proof of concept prior to the creation of the company Tiamat”, a CNRS spinout commercialising sodium-ion cells from its base in Amiens.
Hard carbon anodes and low-energy cathode synthesis are central to CEA’s sodium-ion development strategy. “We aim to develop a low-cost process for producing hard carbon,” Patoux noted. Potassium-ion, though still in earlier stages, brings its own advantages. “One of the benefits of potassium is that you can use graphite,” he explained. “Graphite is less expensive than hard carbon.”
Potassium also delivers stronger voltage performance than sodium. “For the same structures, sodium-ion is about 300 millivolts lower than lithium-ion and potassium,” Patoux explained. “Potassium is more comparable to lithium.” For both sodium and potassium-ion technologies, cathodes based on Prussian Blue Analogues are extensively studied in CEA’s labs. They can be produced at a low temperature (low process price) and involve only affordable components (iron, manganese, carbon and nitrogen).
CEA is also exploring lithium-metal anodes, which promise game-changing energy density but pose significant safety and manufacturing challenges. “Lithium metal is very complicated to use,” Patoux said, citing dendrite formation and sensitivity to impurities.
To address these risks, CEA is developing solid-state electrolytes specifically designed for lithium metal. “We start with lithium ingots and produce fresh lithium metal foil – ready to use,” Patoux said. “It’s not for commercial use yet – our focus is on prototyping to boost energy density to 350, 400, even 450Wh/kg.”
Battery sovereignty
The programme spans 17 R&D projects, in addition to equipment upgrades. It not only addresses new battery chemistries (for Li, Na, K-ion, redox flow etc.), but also advanced BMS, methods and tools. “It’s not industrial work yet, but ultimately it’s intended for the industry – not for just today, but for tomorrow,” Patoux clarified.
CEA also plays a pivotal role in European battery initiatives, participating in around 25 concurrent EU programmes. “We are quite involved in different European frameworks like the Batteries European Partnership Association (BEPA)and Battery 2030+,” Patoux said.
Despite CEA’s strong research capabilities, Patoux stressed that France’s greatest and most urgent hurdle is scaling up industrial production (the same situation as at the European level). “The main challenge today is on the industrial side,” he said. “Improving production yield is extremely difficult.”
CEA is collaborating closely with gigafactory developers and end-users, such as ACC and Stellantis, to support process optimisation, but Patoux cautioned that Europe’s battery sovereignty hinges on securing upstream supply chains. “If we don’t control the first stage of the value chain, we’re not truly sovereign,” he said. “We need agreements and partnerships with countries like Chile, Bolivia, Argentina and Australia for access to raw materials, and we need industrial capabilities in Europe to refine and synthesise materials at a battery grade level.”
Sustainability and strategic materials
CEA’s push for alternative chemistries is not just about cost – it’s about resilience. “It’s easier to access manganese and iron compared to nickel and cobalt,” Patoux said. “Let’s continue to develop new solutions with higher sustainability and a longer lifespan.”
With 10,000m2 of dedicated facilities – including 1,000m2 of dry room space – CEA is fully equipped to prototype, (abuse) test and scale next-generation battery technologies.
“We’re highly flexible when it comes to technologies and processes,” Patoux concluded. “And we maintain strong connections with both academic institutions and industry partners.”
