Using lithium metal electrode for the next generation of Lithium Ion Batteries (LIB) possesses the advantage of high energy around 300 Wh/kg coupled with progressed cathode material [1]. However, the formation of lithium dendrites and mossy lithium under electrochemical load (cycling) are currently the major hindrance of a wider use of such material and commercialization of the concept. Recently, the aforementioned challenges have been analyzed by means of nuclear magnetic resonance and found [2]. Those formations lead to degradation processes which are not yet understood at the micro- and nanometer scale. Therefore, experiments with high spatial resolution under realistic conditions gaining a better understanding of such phenomena are of utmost importance. Based on the practical significance for various applications the in-situ atomic force microscopy (AFM) characterization under electrochemical load is a key to develop new devices with improved functionality. Within this contribution we present combined atomic force microscopy and cyclic voltammetry (CV) measurements of the electrode-electrolyte interface between lithium anode and LP 30 (LiPF₆ in EC/DMC), a common electrolyte in conventional energy storage. Therefore, the simultaneous investigation of structural, electrochemical and mechanical properties under electrochemical conditions is demonstrated. We will discuss the formation of mossy lithium as well as the formation of dendrites within the in-situ AFM results. Our results shed light onto the small scale processes on lithium metal anodes for LIBs and path the way towards applicability of bare lithium as anode material.

References:

[1] J. Wandt et al, Energy Environ. Sci., 2015, 8, 1358

[2] S. Kayser et al., arXiv: 1710.02577, 2017

https://arxiv.org/ftp/arxiv/papers/1710/1710.02577.pdf