Batteries must perform well, but age well too

Prof. Dr. Maitane Berecibar leads the Battery Innovation Centre at the Electromobility Research Centre (MOBI) of the Vrije Universiteit Brussel, where batteries are studied not as isolated components but as complex systems with a full life cycle. From early-stage prototyping to reuse and recycling, her research covers nearly every step in the battery value chain. By combining advanced experimental facilities with digital modelling and machine learning, her team tackles one of Europe’s key technological challenges: building battery technologies that are not only high-performing, but also safe, scalable and sustainable. 

“So the topic my team works on is batteries,” Berecibar says, before clarifying what that actually means in practice. “We start right at the beginning, with small coin-cell prototypes, to explore what future battery technologies could look like.” 

Those early prototypes allow her group to investigate emerging technologies such as solid-state and sodium-ion batteries. But for Berecibar, promising chemistry is only the first step. “Manufacturing is a crucial challenge for Europe,” she explains. “You can have an excellent result in a coin cell, but that doesn’t automatically translate into something you can produce reliably.” 

Her team therefore works on upscaling, moving from small laboratory cells to larger formats such as pouch cells. “That transition is not straightforward,” she says. “Understanding how manufacturing choices affect performance, safety and lifetime is essential if we want these technologies to leave the lab.” 

A second core research line focuses on advanced sensors embedded at the level of individual battery cells. “In an electric vehicle, a battery pack can contain more than 8,000 cells,” Berecibar notes. “We mainly measure voltage, current and temperature. Everything else is inferred through models.” 

Sensors change that situation by providing direct insight into what happens inside a cell during operation. “They allow us to detect early signs of degradation or failure,” she says. “That knowledge is key if you want to extend battery lifetime or improve safety.” 

This work naturally leads to one of the lab’s most forward-looking topics: self-healing batteries. “If sensors indicate that micro-cracks or other damage are forming, self-healing materials could intervene,” Berecibar explains. “It’s not something you’ll see on the road tomorrow, but combining sensors, self-healing mechanisms and control systems could make batteries both safer and longer-lasting.” 

Beyond the cell itself, her group studies how batteries behave in real-world applications. “We work on batteries for electric vehicles, drones, boats and stationary storage,” Berecibar says. Both in-house prototypes and commercial cells are tested to build models for performance, safety and lifetime, including thermal management and grid integration. 

One area that has gained particular momentum is second life — the reuse of batteries that are no longer suitable for vehicles. “When an electric-vehicle battery is retired at around 80% capacity, it still has significant value,” she says. “It can be used for stationary applications, for example in households or local energy grids.” 

Making second life viable, however, requires careful assessment. “You need to understand how much lifetime is left and how safety evolves,” she adds. “There is scepticism, but from a sustainability perspective, this approach simply has to be part of the solution.” 

Across all these research lines, digitalisation and machine learning play an increasingly important role. “We combine high-quality experimental data with digital tools,” Berecibar explains. “Sometimes we extrapolate from lab results; sometimes we explore digitally which materials or designs are worth testing next.” 

This hybrid approach helps translate laboratory insights to new applications more efficiently. “You can’t experimentally test every possible scenario,” she says. “Digital tools help us make smarter, faster decisions.” 

The Battery Innovation Centre, based on the VUB’s Etterbeek campus, brings together around 20 researchers, including PhD students, senior scientists and support staff. “With many European, national and industrial projects running, coordination is essential,” Berecibar notes. 

A recent milestone was the Francqui Prize, which enabled major investments in new equipment and opened the door to battery recycling research. “Recycling is one of the big questions facing Europe,” she says. “We already work on performance and second life, so moving into recycling is a logical next step.” 

Looking ahead, Berecibar sees sustainability as the central challenge of the coming decade. “The batteries we have today are already quite safe,” she says. “The biggest gap to close is sustainability — longer lifetimes, fewer critical materials and better recycling.” 

She emphasises that no single battery technology will fit every application. “We need a portfolio,” she says. “High-energy-density solutions for mobility, but other chemistries — like sodium-ion — for stationary storage. Each application requires its own balance.” 

Asked about her most significant breakthroughs, she points to two areas. “The work on sensors and self-healing batteries, where we are really pioneering in Europe, and the research on second life,” she says. “Many people doubt the latter, but for sustainability reasons, it has to happen.” 

Her recent inclusion among the top 1% most cited researchers worldwide came as a surprise. “It doesn’t feel like a personal achievement,” she says with a smile. “It reflects the strength of the team.” 

Finally, Berecibar stresses the importance of attracting more women to engineering and battery research. “In chemistry the balance is improving, but in application-oriented engineering fields the numbers are still low,” she says. “Excellence is always the criterion — but we also need to make sure people feel welcome to enter the field.”