Electrochemical Response of Metal Electrodes in Contemporary Batteries

High Resolution Image Download MS PowerPoint Slide Alkali metal electrodes are considered promising enablers of next-generation high energy density batteries and are commonly utilized in half cells for electrochemical characterization of battery materials. Their high reactivity with common battery electrolytes and nonplanar electrodeposition under constant current drives complex interphase formation and morphological instability, challenging a stable and reliable application. This review highlights how electrochemical methods─specifically electrochemical impedance spectroscopy (EIS) and galvanostatic polarization in symmetric cells─provide powerful, in situ, and nondestructive tools to study material properties and the kinetics of their degradation in cells. We summarize recent key findings and demonstrate how time, temperature, and current-dependent electrochemical responses yield valuable insights into the electrochemical and morphological stability and kinetics of both naturally formed and artificial alkali metal interphases. We further show how both methods are effectively used to understand the charge-transfer process and diffusion under anion-blocking conditions and determine effective cationic transference numbers of a variety of contemporary battery electrolytes, essential for their structure–property evaluation.