Temporal Evolution of Lithium Plating and SEI Formation in Anode-Less Batteries Probed By in-Operando AFM

ECS Meeting Abstracts, vol. MA2025-02, pp. 244

Abstract

The successful application of metallic lithium as anode material, also in anode-free batteries, is currently impeded by the loss of electrochemically active lithium during the continuous formation of the solid electrolyte interphase (SEI) as well as a short lifetime caused by formation of dendritic lithium and internal shorting.[1, 2] A deeper understanding of the solid-electrolyte interphase formation and its properties is essential to tackle these challenges. In particular, understanding the correlation between SEI properties, electrolyte composition and growth morphology of lithium metal is a great asset for advantageous electrolyte design to achieve dendrite-free batteries. In this contribution, we investigated the morphology of deposited Li while simultaneously probing the mechanical stability of the outer surface layer by in-operando atomic force microscopy (AFM). An advanced in-operando mode of AFM is demonstrated to assess the morphology as well as mechanical properties such as Young´s modulus of the lithium metal surface simultaneously under operating conditions in carbonate-based electrolytes and a protective gas atmosphere. In particular, the influence of the additive vinylene carbonate (VC) on the electrodeposition of lithium metal is probed. We demonstrate an impact of electrolyte composition on the deposition morphology. Furthermore, we analyse the mechanical properties of the outer surface layer.[3,4] Importantly, a “mechanical fingerprint” is identified for each electrolyte, which is obtained for surface layers on both copper and lithium surfaces. Moreover, the influence of native passivation layers on SEI formation and its mechanical properties is assessed. Their heterogeneity requires careful experimental design for studies of specific SEI properties. A careful comparison of the SEI properties obtained in-situ and after drying revealed a significant difference in mechanical data. This observation underlines the necessity for in-situ characterisation techniques and is critically discussed.

Authors 5

1. Beatrice Wolff

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH, IET-1

2. Peter Jakes

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH (IET-1)

3. Rüdiger‐A. Eichel Aachen Institute of Physical Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich GmbH, IET-1

   RWTH Aachen University, Institute of Physical Chemistry

4. Josef Granwehr Aachen Institute of Technical and Macromolecular Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich GmbH (IET-1)

   RWTH Aachen, Institute of Technical and Macromolecular Chemistry

5. Florian Hausen Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Institute of Physical Chemistry