Laser-based manufacturing technologies could play a decisive role in transferring solid-state batteries from laboratory prototypes to industrial production, according to researchers at Fraunhofer Institute for Laser Technology ILT in a paper published on 26 February.
Solid-state batteries are widely viewed as the next generation of electrochemical energy storage, offering higher energy density, improved intrinsic safety and greater design flexibility compared with conventional lithium-ion cells that use liquid electrolytes. However, significant manufacturing barriers remain before large-scale production can be realised.
Researchers at Fraunhofer ILT are investigating how laser processes can address key bottlenecks, including electrolyte sintering, interface optimisation and lithium metal processing.
One focus area is the laser sintering of oxide ceramic solid electrolytes such as lithium lanthanum zirconate (LLZO). Traditional furnace sintering at temperatures of around 1,200°C can result in lithium losses and secondary phase formation, reducing ionic conductivity and increasing material waste. By contrast, laser radiation offers rapid, localised heating with controlled cooling, potentially reducing lithium loss and improving densification.
“The key advantage of solid-state batteries lies in their intrinsic safety,” said physicist Stoyan Stoyanov from the cutting department at the Fraunhofer Institute for Laser Technology ILT. “Since they do not use liquid electrolytes, there is no risk of leakage or thermally induced fires. Additionally, the high mechanical stability of many solid electrolytes inhibits the formation of lithium dendrites, which are the main cause of internal short circuits in conventional cells.”
Besides safety, higher energy density is the main driving force. Lithium metal anodes with a specific capacity of 3860 mAh g⁻¹ outperform graphite anodes by far. Combined with thin, solid electrolytes, this enables advantages in range and weight, a decisive factor for electromobility and aviation.
The first fields of application are emerging where maximum safety and performance are crucial: in aerospace, motorsports, medical technology, and high-security data storage. Here, the higher energy density justifies the complex manufacturing process.
For the mass market, economic competitiveness remains limited for now. The production infrastructure is still being developed, and established lithium-ion systems continue to evolve in parallel.
“Solid-state batteries will exist alongside conventional lithium-ion cells for the foreseeable future and will primarily serve particularly demanding applications in the automotive industry, such as the luxury vehicle market,” said Stoyanov.
Interface engineering for solid-state battery manufacturing
Interface engineering is another critical challenge. High interfacial resistance between solid electrolytes and lithium metal anodes can limit performance and cycle life. Fraunhofer ILT researchers are using ultrashort-pulse lasers to introduce microstructures, typically around 30µm in scale, to increase effective contact area and promote more uniform current distribution.
Lithium metal handling presents additional difficulties. The material is highly reactive, soft and adhesive, complicating mechanical cutting. Contact-free laser cutting under inert atmospheres such as argon enables more precise geometries and reduces tool wear, although process control is essential to prevent particle formation and surface defects.
According to the institute, laser technologies are already well established in lithium-ion production, including slitting, drying and notching processes. Adapting and refining these techniques for solid-state systems could help reduce reject rates and improve scalability under the dry room or inert gas conditions required.
Fraunhofer ILT is also exploring the integration of thin-film sensors and AI-supported monitoring to improve battery management and process control.
While solid-state batteries are expected initially to serve high-performance sectors such as aerospace and premium automotive, researchers believe robust, laser-enabled manufacturing routes could support broader market adoption over time.
Main image: Researchers at Fraunhofer ILT are developing laser-based processes for manufacturing solid-state batteries Credit: Fraunhofer ILT, Aachen, Germany
