Aluminum current collector for high voltage Li-ion battery. Part I: A benchmark study with statistical analysis

The protection of current collectors against anodic dissolution at high potential has been identified as crucial for next generation of high energy and safe lithium-ion batteries. Herein, a systematic study of the electrochemical behavior of two grades of aluminum current collectors has been performed in five representative liquid electrolytes. Analysis of electrochemical data and microscopy images have notably shown that aluminum current collectors appear to be stable up to 5 V vs. Li+/Li in the presence of the reactive LiPF6 salt whereas imide salts trigger the aluminum anodic dissolution except in ionic liquid medium. It was also observed that the grade of the tested aluminum current collectors had little impact. To support the robustness of this study dedicated to practical developments of the “5 V” Li-ion battery technology, a statistical analysis has been performed for the most corrosive electrolyte formulation (1 M LiTFSI/[EC/DMC]). These data show the anodic dissolution systematically occurs in a reproducible way whatever the sampling area of the aluminum foil.