Nanoscale observation of the solid electrolyte interface and lithium dendrite nucleation–growth process during the initial lithium electrodeposition

Abstract

Lithium metal is one of the most promising anode materials for next-generation batteries. However, the growth of lithium dendrites and the high reactivity of lithium cause serious safety and cyclability problems. A comprehensive understanding of the lithium deposition behavior, especially during the initial deposition stages, is critical for its performance improvement. The influences of current density and capacity on the nucleation size, site distribution, and growth pattern were discussed via in situ electrochemical AFM (EC-AFM) and COMSOL simulation, suggesting that lithium deposition initially follows reaction- and then transport-limited mechanisms. In addition, the solid electrolyte interface (SEI) during lithium deposition was systematically analyzed by conductive-AFM, AFM force probing and X-ray photoelectron spectroscopy (XPS) depth profiling to give a comprehensive picture of the electronic, mechanical and chemical properties of SEI film under realistic conditions.