Lithium Metal Growth Kinetics on LLZO Garnet Type Solid Electrolytes – <i>Operando</i> Study of Lithium Deposition and Dendrite Growth

Abstract

Li₇La₃Zr₂O₁₂ (LLZO) based garnet materials are recently investigated as suitable electrolytes for solid state batteries with lithium metal electrode. Unfortunately, lithium metal penetration through polycrystalline garnet type electrolytes limits the electric current density during cell charging. In this study, we introduce an electrochemical operando approach that is a well suited to get insights into the early stage of lithium metal penetration that was yet only accessible with very elaborate neutron measurements. Combined with in situ as well as ex situ electron microscopic techniques, we investigate the morphological instability of the lithium metal anode on garnet type solid electrolytes under cathodic load and demonstrate the interrelationship between microkinetic aspects and lithium penetration susceptibility.