Correlative Electrochemical Microscopy for the Elucidation of the Local Ionic and Electronic Properties of the Solid Electrolyte Interphase in Li‐Ion Batteries

• Published in: Angewandte Chemie International Edition Vol. 61; no. 26; pp. e202202744 - n/a
• Main Authors: Santos, Carla S., Botz, Alexander, Bandarenka, Aliaksandr S., Ventosa, Edgar, Schuhmann, Wolfgang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 27.06.2022; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Electrochemistry; Electron transfer; Electronic properties; Interphase; Li-Ion Batteries; Lithium; Lithium-ion batteries; Local Electrochemical Impedance Spectroscopy; Microscopy; Scanning Electrochemical Microscopy; SEI Properties; Solid Electrolyte Interphase; Solid electrolytes; Solid Electrolyte Interphase; Scanning Electrochemical Microscopy; Local Electrochemical Impedance Spectroscopy; SEI Properties; Li-Ion Batteries
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202202744

The solid‐electrolyte interphase (SEI) plays a key role in the stability of lithium‐ion batteries as the SEI prevents the continuous degradation of the electrolyte at the anode. The SEI acts as an insulating layer for electron transfer, still allowing the ionic flux through the layer. We combine the feedback and multi‐frequency alternating‐current modes of scanning electrochemical microscopy (SECM) for the first time to assess quantitatively the local electronic and ionic properties of the SEI varying the SEI formation conditions and the used electrolytes in the field of Li‐ion batteries (LIB). Correlations between the electronic and ionic properties of the resulting SEI on a model Cu electrode demonstrates the unique feasibility of the proposed strategy to provide the two essential properties of an SEI: ionic and electronic conductivity in dependence on the formation conditions, which is anticipated to exhibit a significant impact on the field of LIBs. Combining feedback (FB) and multi‐frequency alternating‐current (AC) SECM methodologies is proposed as a unique approach that provides the two essential properties namely the ionic and electronic conductivity of the solid electrolyte interphase (SEI) in Li‐ion batteries quantitatively. The influence of the electrolyte composition and the SEI formation protocol on the properties of the resulting SEI was derived.