Enhanced fast charging and reduced lithium-plating by laser-structured anodes for lithium-ion batteries

Within this paper we report on a lithium-ion battery with laser-structured graphite anodes, alleviating current drawbacks of lithium-ion batteries such as the reduced discharge capacity at high C-rates and the on-set of lithium-plating during fast charging. These issues are intensified at low temperatures, as reaction and diffusion kinetics decelerate, which is why a focus of the presented work lies on low temperature performance. Electrochemical impedance spectroscopy was used to show a reduction in the impedances of cells with laser-structured anodes in comparison to their conventional counterparts. The discharge capacity retention at high C-rates was enhanced by up to 27% compared to conventional cells, proving potential for high power applications. For the cells with laser-structured anodes, the on-set of lithium-plating at 0°C was observed at higher charging C-rates by analyzing the voltage relaxation after charging. At −15°C, a smaller amount of plated lithium was detected, even though lithium-plating could not be entirely avoided. Laser structuring also enabled shorter charging times, as the upper cutoff voltage was reached at a higher SOC. The results point out that laser structuring of the anode improves the fast charging capability of lithium-ion cells, especially under demanding operating conditions.