Optimizing and upscaling of USP laser structuring for 3D lithium-ion battery electrodes for fast-charging and reduced lithium plating

Various concepts for upscaling the laser structuring of electrodes for lithium-ion batteries are studied on commercial lithium-iron-phosphate electrodes. Attention was paid to the thermal modifications of the active material due to high power laser material processing. Therefore, the influence of ultrashort pulse widths in the range of 220 fs were compared to the ablation with pulse widths in the range of 600 fs. The realization of the ultrashort pulses was achieved through self-phase modulation based spectral broadening and subsequent pulse compression via chirped mirrors. Furthermore, the influence of GHz pulse burst ablation on ablation efficiency was studied for varying pulse burst lengths from 50 ns to 500 ns. The ablation result of the lithium-iron-phosphate electrodes with various pulse width and pulse bursts were evaluated in terms of processing quality and compared to single pulse ablation. In addition, fast-charging capability of full cells with all possible combinations of structured and unstructured electrodes were examined in a charge and discharge rate capability test, differential voltage analysis of the voltage relaxation, and post-mortem studies to examine the fast-charging capability and lithium plating behavior.