Enhanced performance and lifetime of lithium-ion batteries by laser structuring of graphite anodes

Abstract

Improving the performance characteristics of lithium-ion batteries is a central research objective for the widespread introduction of electric vehicles. Laser-induced structures in graphite anodes have been reported to improve various performance characteristics of lithium-ion batteries. Nevertheless, electrode structuring has been studied mostly with single-layer coin cells on a laboratory scale to date. In addition to electrochemical tests on multi-layer NMC111/graphite pouch cells with a nominal capacity of ≈ 2.9 Ah, this paper presents the transfer of the technology from the laboratory to an industry-oriented battery production scale. A significant improvement of the discharge rate capability of lithium-ion batteries with laser-structured anodes was observed at temperatures of -10 °C, 0 °C, and 25 °C at discharge rates of up to 8C. Moreover, an enhanced fast-charging capability at charge rates as high as 6C was determined. In an aging study with 500 charge and discharge cycles, a significantly higher capacity retention of cells containing structured anodes was demonstrated. The effects of aging were investigated by incremental capacity analyses. Additionally, the results are supported by post-mortem analyses of the anode material using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The investigations revealed a distinctly reduced surface layer formation on structured anodes in comparison to their non-structured counterparts, which is attributed to a decrease in lithium-plating during cycling.