Laser-structured anodes for high-power lithium-ion batteries: A journey from coin cells to 21700-type cylindrical cells

This study investigates the innovative use of lasers to modify anodes in lithium-ion batteries, targeting enhanced stability and performance in high-power applications. Although laser structuring of electrodes is welldocumented, it is usually restricted to small areas and lab-scale cells. Our research stands out by implementing laser-structured electrodes in 21700-type cylindrical cells. Laser parameters, structuring patterns, and pit dimensions were meticulously optimized to reduce electrode tortuosity. Microstructural analyses verified that the active materials were not damaged by the laser energy during structuring. This structuring significantly decreased ionic pore resistance in the anode, as evidenced by symmetrical coin cell and half-cell studies. Intermediate upscaling with bi-layer pouch cells confirmed improved rate performance and long-term cycling stability, despite the low N/P ratio. As a final proof of concept, 21700 cylindrical cells were assembled with laser-structured anodes, resulting in a 42 % increase in CC charging capacity at 20 A and no lithium deposition issues. Discharge performance improved by 21 % at 30 A and 11 % at 35 A, with lower temperature increases. Despite some variability in the manufacturing process, the long-term cycling stability of the 21700 cells matched that of unstructured references, demonstrating the viability and potential of cylindrical TRL 4-level cells with laser-structured anodes.