Galvanic Corrosion of Lithium-Powder-Based Electrodes

Abstract

Lithium metal is considered to be the most promising anode for the next generation of batteries if the issues related to safety and low coulombic efficiency can be overcome. It is known that the initial morphology of the lithium metal anode has a great influence on the cycling characteristics of a lithium metal battery (LMB). Lithium-powder-based electrodes (Lip-electrodes) are reported to diminish the occurrence of high surface area lithium deposits. Usually, ultra-thin lithium foils (<50 µm) and Lip-electrodes are prepared on a copper substrate, thus a metal–metal contact area is generated. The combination of these two metals in the presence of an electrolyte, however, can lead to galvanic corrosion. Herein, the corrosion behavior of Lip-electrodes is studied. The porosity of such electrodes leads to a high amount of accessible Cu surface in contact with electrolyte. As a consequence, Lip-electrodes aged for 1 week in the electrolyte show spontaneous lithium dissolution near the junction to copper and void formation on the lithium-powder particles. This corrosion process affects the delivered capacity of Lip-electrodes and increases the overvoltage of the lithium electrodissolution process. The occurrence of corrosion at the Cu|Lip interface raises concerns about the practicality of multi-metallic component systems for LMBs.