To address these limitations, we present a comprehensive understanding of the voltage variations observed during initial Li metal cycling, which is directly correlated to morphology evolution through the use of operando video microscopy . A custom-designed visualization cell was developed to enable in situ synchronized observation of Li metal electrode morphology and electrochemical behavior during cycling. A mechanistic understanding of the complex behavior of these electrodes is gained through correlation with continuum-scale modeling, which provides insight into the dominant surface kinetics. This work provides a comprehensive explanation of (1) when dendrite nucleation occurs, (2) how those dendrites evolve as a function of time, (3) when surface pitting occurs during Li electrodissolution, (4) kinetic parameters that dictate overpotential as the electrode morphology evolves, and (5) how this understanding can be applied to evaluate electrode performance in a variety of electrolytes. An understanding of how the impedance of reaction pathways change during cycling is used to provide predictive insight into the behavior lithium metal anodes. This provides detailed insight into the interplay between morphology and the dominant electrochemical processes occurring on the Li electrode surface through an improved understanding of changes in cell voltage, which represents a powerful new platform for analysis.
1. K. N. Wood, E. Kazyak, A. F. Chadwick, K.-H. Chen, J.-G. Zhang, K. Thornton, N. P. Dasgupta, ACS Central Science 2, 790 (2016).