Surface layer formation on Sn anode: ATR FTIR spectroscopic characterization

• Published in: Electrochimica acta Vol. 54; no. 4; pp. 1312 - 1318
• Main Authors: Song, Seung-Wan, Baek, Seung-Won
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 30.01.2009; Elsevier
• Subjects: Applied sciences; ATR FTIR; 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; Interfacial reaction; Lithium-ion battery; Surface chemistry; Tin anode; Lithium-ion battery; ATR FTIR; Interfacial reaction; Tin anode; Surface chemistry; Surface reaction; Fourier transformation; Anode; Surface layer; Electrode electrolyte interface; Secondary cell; Electrode material; Infrared spectrometry; Total attenuated reflection; Thin layer electrode; Tin; Lithion ion batteries; Lithium Hexafluophosphates
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2008.09.021

Surface layer formed on Sn thin film electrode in 1 M LiPF 6/EC:DMC electrolyte was characterized using ex situ FTIR spectroscopy with the attenuated total reflection technique. IR spectral analyses showed that the immersion of Sn film in the electrolyte resulted in a chemical interfacial reaction leading to the passivation of Sn surface with primarily PF-containing inorganic surface species and small amount of organics. When constant current cycling was conducted with lithium cells with Sn film electrode at 0.1–1.0 V vs. Li/Li +, the interfacial reaction between Sn and electrolyte appeared significantly intensified that the features of PF-containing species became enhanced and new IR features of organic species (e.g. alkyl carbonate/carboxylate metal salts and ester functionalities) were observed. The surface layer continued to form with cycling, partly due to non-effective surface passivation as well as particle pulverization accompanied by enlargement of active surface area. Comparative IR spectral analyses indicated that the interfacial reaction between Sn and PF 6 − anion played a leading role in forming the surface layer, which is different from lithiated graphite that had mainly organic surface species. The data contribute to a better understanding of the interfacial processes occurring on Sn-based anode materials in lithium-ion batteries.