Comparative Evaluation of Graphite Anode Structuring for Lithium-Ion Batteries Using Laser Ablation and Mechanical Embossing

Lithium-ion batteries inherently suffer from a target conflict between a high energy density and a high power density. The creation of microscopic holes in the electrodes alleviates the trade-off by facilitating lithium-ion diffusion. This study presents a novel concept for electrode structuring called structure calendering, combining mechanical embossing (MEC) and calendering. It is compared to the widely investigated laser ablation (LAS) process by structuring graphite anodes and examining their geometrical, mechanical, and electrochemical properties. It is shown that structure calendering results in wider and deeper holes of higher reproducibility than laser structuring. As a consequence of the different hole-creation mechanisms, laser structuring induces a surface elevation around the holes while clogged pores are observed in the lateral walls of mechanically structured holes. In pull-off tests, no pronounced impact of electrode structuring on the mechanical electrode properties is discerned. Structuring of electrodes using both methods yields significantly reduced electrode tortuosities and enhanced discharge rate performances. From a production engineering perspective, structure calendering has advantages over laser structuring in terms of material loss, processing rate, and investment costs, while the latter offers higher flexibility, precision, and presumably lower maintenance efforts. In conclusion, structure calendering represents an attractive process alternative to laser structuring. This study presents a novel concept for electrode structuring called structure calendering, combining mechanical embossing and calendering. It is compared to the widely investigated laser structuring of graphite anodes by examining electrodes' geometrical, mechanical, and electrochemical properties. Furthermore, production engineering aspects of both processing alternatives are evaluated. In conclusion, structure calendering represents an attractive process alternative to laser structuring.image (c) 2024 WILEY-VCH GmbH