Regulating Key Variables and Visualizing Lithium Dendrite Growth: An Operando X-ray Study.

Although Li metal has long been considered to be the ideal anode material for Li rechargeable batteries, our limited understanding of the complex mechanism of Li plating has hindered the widespread deployment of Li metal anodes. Therefore, operando studies are required to unambiguously reveal the complex mechanistic steps involved. In this study, we employed synchrotron-based X-ray imaging methods to visualize the evolution of Li plating/stripping under operando and, more importantly, practical conditions for battery operation, providing detailed insights into morphology evolution during Li plating. The effects of critical battery operating parameters, including concentration of Li salts, current density, ionic strength, and various electrolytes and additives, on Li plating/stripping have been studied. The delicate interplay of these conditions on the resulting Li metal morphology has been characterized for the first time.