In situ AFM studies of SEI formation at a Sn electrode

• Published in: Electrochemistry communications 2009-11, Vol.11 (11), p.2157-2160
• Main Authors: Lucas, Ivan T., Pollak, Elad, Kostecki, Robert
• Format: Article
• Language: English
• Subjects: Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; In situ AFM; Li-ion battery; SEI layer; Sn anode
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2009.09.019

Early stages of the solid electrolyte interphase (SEI) formation at a tin foil electrode in an ethylene carbonate (EC) based electrolyte were investigated by in situ AFM and cyclic voltammetry (CV) at potentials >0.7 V, i.e., above the potential of Sn–Li alloying. We detected and observed initial steps of the surface film formation at ∼2.8 V vs. Li/Li + followed by gradual film morphology changes at potentials 0.7 < U < 2.5 V. The SEI layer undergoes continuous reformation during the following CV cycles between 0.7 and 2.5 V. The surface film on Sn does not effectively prevent the electrolyte reduction and a large fraction of the reaction products dissolve in the electrolyte. The unstable SEI layer on Sn in EC-based electrolytes may compromise the use of tin-based anodes in Li-ion battery systems unless the interfacial chemistry of the electrode and/or electrolyte is modified.