Fraunhofer Project Uses Amorphous Carbon Coatings to Extend Lithium-Metal Battery Life

Amorphous carbon coatings for longer-lasting lithium-metal batteries

The demand for more powerful and lighter battery systems is growing. Batteries with high energy density and long service life are in high demand, particularly for electric mobility, aerospace, and stationary energy storage. The Fraunhofer Institute for Surface Engineering and Thin Films IST is therefore collaborating with the Fraunhofer USA Center Midwest (CMW) to explore new approaches for improving the performance and service life of future battery systems. One promising approach involves lithium-metal anodes, in which lithium itself serves as the active anode material; due to its high specific capacity, this enables battery cells with potentially higher energy density.

To harness the potential of lithium-metal anodes for longer-lasting battery cells, the new research project “LIMAC – Amorphous Carbon Interlayers for Reliable Lithium-Metal Battery Cells” focuses on thin amorphous carbon interlayers. The central question is whether these layers can stabilize the interface between the lithium-metal anode and the (solid) electrolyte, thereby contributing to more reliable and longer-lasting battery cells. To this end, the first step will involve developing thin amorphous carbon layers and depositing them onto copper current collectors using an innovative laser-arc PVD process. The coated materials will then be tested in battery cells and compared with reference cells. The aim is to determine which properties of the interlayers are crucial for achieving the most stable interface possible within the battery cell.

From the laboratory scale to larger battery cells

In addition to technical performance, the project also considers the environmental perspective and the potential for transferring the technology to larger cell formats. On the one hand, a life cycle assessment (LCA) will be used to examine relevant material and energy flows as well as the environmental impacts of the approach; on the other hand, a concept for scaling the technology to larger pouch cells will be developed simultaneously. In this way, the project combines material development and cell research with environmental assessment and initial considerations for future scaling. The goal is to comprehensively evaluate the potential of amorphous carbon interlayers for more reliable lithium-metal batteries and establish a foundation for further development toward larger cell formats.

In the long term, more powerful and longer-lasting lithium-metal batteries could help reduce the weight of battery systems while enabling high energy densities. This could benefit applications where weight, performance, and range play a key role – from electric vehicles to aerospace and stationary energy storage systems.

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Amorphous carbon coatings for longer-lasting lithium-metal batteries, source