Impact of a PEO-based Interphase at the Negative Electrode of “Zero Excess” Lithium-Metal Batteries

• Published in: Journal of the Electrochemical Society Vol. 169; no. 11; pp. 110521 - 110528
• Main Authors: Geng, Katrin, Eisenmann, Tobias, Parmar, Rahul, Rezvani, Javad, Gunnella, Roberto, Amati, Matteo, Gregoratti, Luca, Stepien, Dominik, Diemant, Thomas, Bresser, Dominic
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.11.2022
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/ac9f74

“Zero-excess” lithium-metal batteries represent a very promising next-generation battery concept, enabling extremely high energy densities. However, lithium metal deposition is often non-uniform and accompanied by severe side reactions with the electrolyte, limiting Coulombic efficiency and, thus, energy density and cycle life. To address this issue, we introduced a thin polymer-based artificial interphase at the negative electrode. The influence of this interphase on the lithium deposition, and generally the reactions occurring at the negative electrode, was evaluated by galvanostatic stripping/plating tests and a thorough ex situ analysis via scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), scanning photoemission microscopy (SPEM), and soft-X-ray absorption spectroscopy (soft-XAS). The results demonstrate that the introduction of such a polymer-based interlayer allows for more stable cycling and reduces dendritic lithium growth owing to the formation of a more homogeneous, thin, and fluorine-rich passivation layer.