In Situ Mechanical Analysis of the Nanoscopic Solid Electrolyte Interphase on Anodes of Li‐Ion Batteries

The interfacial decomposition products forming the so‐called solid–electrolyte interphase (SEI) significantly determine the destiny of a Li‐ion battery. Ultimate knowledge of its detailed behavior and better control are required for higher rates, longer life‐time, and increased safety. Employing an electrochemical surface force apparatus, it is possible to control the growth and to investigate the mechanical properties of an SEI in a lithium‐ion battery environment. This new approach is here introduced on a gold model system and reveals a compressible film at all stages of SEI growth. The demonstrated methodology provides a unique tool for analyzing electrochemical battery interfaces, in particular in view of alternative electrolyte formulations and artificial interfaces.