Laser cutting of pure lithium metal anodes - Effects of atmospheric conditions

Abstract

Aiming at a high performance lithium-ion battery, all process steps and materials have to be improved. Lithium metal is the most promising material for future anodes based on their high theoretical capacity of 3860 mAh/g and their low density of 0.534 g/cm3. Apart from the actual low cycle stability of those anodes, challenges lay in the separation and handling of lithium. Due to its toughness and adhesive properties, lithium metal anodes cannot be separated by conventional processes (e.g. punching), especially a constant and good cut quality is a significant challenge for large batch production. Remote laser cutting as a flexible and wear-free method for highly reproducible cutting is one promising option to cut lithium metal anodes within a significant quantity. The process has the potential to achieve higher quality than the conventional processes. Due to the good scalability and high automation, laser-based electrode cutting is a suitable process with expected high throughput speed. The influence of pulse repetition rate, cutting speed, pulse duration, power and atmospheric conditions on cutting edge quality were investigated considering melt superelevation, melt formation and contamination by chemical reactions with the atmosphere.