Researchers from two Fraunhofer institutes are investigating whether thin amorphous carbon layers can improve the stability and durability of lithium-metal batteries. The work focuses on the interface between the lithium-metal anode and the electrolyte, a critical area for developing battery cells with improved performance and longer service lives.
The research is being conducted through the LIMAC project, short for “Amorphous Carbon Interlayers for Reliable Lithium-Metal Battery Cells”. The Fraunhofer Institute for Surface Engineering and Thin Films IST is collaborating with the Fraunhofer USA Center Midwest on the initiative, which began in September 2025 and is scheduled to run until August 2028.
Stabilising the Lithium-Metal Anode Interface
Lithium-metal anodes offer potential advantages over conventional anode materials because lithium has a high specific capacity. Using lithium itself as an active anode material could help increase battery energy density, creating opportunities for lighter battery systems with greater energy storage capacity.
However, the interface between a lithium-metal anode and its electrolyte presents technical challenges. According to the researchers, improving the stability of this interface is essential to developing more reliable and durable cells.
Under LIMAC, the team is investigating thin amorphous carbon interlayers intended to stabilise the interface. The researchers first deposit these coatings onto copper current collectors using a Laser-Arc Physical Vapour Deposition (PVD) process.
The coated materials will then be incorporated into battery cells and compared with reference cells. This testing is intended to identify which properties of the carbon interlayers contribute most effectively to interface stability.
The approach is designed to allow lithium contained within the cell to function as the active anode material, potentially supporting battery architectures with higher specific capacity.
Assessing Environmental Impacts and Scalability
Beyond electrochemical performance, LIMAC will examine the environmental implications of the proposed technology and its potential for larger-scale application.
A life cycle assessment (LCA) will evaluate relevant material and energy flows, along with the associated environmental impacts. In parallel, the researchers will develop a concept for transferring the technology to larger pouch cells.
These activities combine materials research and battery-cell testing with environmental evaluation and early-stage manufacturing considerations. The findings could help establish whether the approach offers benefits beyond laboratory-scale performance.
Potential Applications in Electric Vehicles
More powerful and longer-lasting lithium-metal batteries could offer advantages for electric vehicle manufacturers. Higher energy density could allow battery packs to store more energy without a proportional increase in weight, potentially supporting lighter vehicles or longer driving ranges.
Improvements in durability could also help extend battery service life. However, these benefits depend on the technology’s performance under practical operating conditions and its ability to be manufactured at scale.
LIMAC remains at the basic research stage. Its work will focus on understanding the role of amorphous carbon interlayers, evaluating their environmental footprint and exploring how the coating process could be adapted for larger battery cells. Commercial viability and real-world performance will depend on the results of further testing and development.