With Coatings Towards Better Batteries, FHNW School of Engineering and Environment

Anode-free solid-state lithium batteries promise higher energy density, lower costs and improved safety – but they still face challenges such as uneven lithium distribution and early capacity loss. In the Nano-Argovia project BatCoat, the research team demonstrates that ultrathin silver and protective coatings on the current collector can solve these issues and significantly extend battery lifetime.

The Nano-Argovia project BatCoat aimed to overcome key technical barriers on the path towards reliable lithium-metal solid-state battery cells. Specifically, the researchers set out to:

• achieve homogeneous, reversible lithium deposition on a copper surface that withstands more than 500 charge and discharge cycles while maintaining high capacity,
• prevent harmful reactions between lithium and the solid electrolyte by applying ultrathin functional coatings made of different materials (<100 nanometres) to the copper surface,
• investigate the advantages of 3D copper structures to mitigate the formation of lithium dendrites at the anode and thereby avoid performance and safety losses,
• develop a concept for the industrial-scale production of nanoscale functional coatings on three-dimensional copper structures.

The team demonstrated that extremely thin coatings on the current collector can significantly reduce several of these issues. For example, a silver coating enables more uniform lithium deposition, while an additional protective layer prevents harmful reactions – allowing for a very high number of charge cycles. Computer simulations also confirmed that the coatings reduce mechanical stress inside the battery and prevent crack formation. Overall, the BatCoat project shows that targeted surface coatings can substantially improve the stability and lifetime of anode-free solid-state batteries.