Study of the solid electrolyte interphase of Li-O2 battery electrolyte by analytical transmission electron microscopy. (17th March 2020)

• Record Type: Journal Article
• Authors: Kitta, Mitsunori; Sano, Hikaru
• Is Part Of: Microscopy. Volume 69:Number 4(2020)
• Page Start: 227
• Page End: 233
• Publication Date: 2020-03-17
• Subjects: Li-O2 battery -- negative electrode surface -- solid electrolyte interphase -- analytical transmission electron microscopy -- specimen preparation; Microscopy -- Periodicals; 502.825
• DOI: 10.1093/jmicro/dfaa012
• Languages: English
• ISSNs: 2050-5698

Abstract

Abstract: Investigation of solid electrolyte interphases (SEIs) on negative electrode surfaces is essential to improve the stable charge-discharge performance of rechargeable lithium-air batteries (Li-O2 batteries). In this study, a direct investigation of SEI films is conducted using analytical transmission electron microscopy (TEM). A thin Cu specimen is prefabricated for TEM observation and is utilised as a model substrate for SEI formation. The electrochemical cell constructed using dissolved oxygen in the electrolyte exhibits a greater electrochemical overpotential during the Li-metal deposition process than that constructed with a pristine electrolyte. This suggests that different electrochemical passivation features occur in each different electrochemical cell. TEM observation confirms that the surface film formed by O2 dissolute electrolyte is a polycrystalline Li2 O film with a thickness of ~5 nm, whereas the film formed by the pristine electrolyte is organic-based, amorphous-like and 20–50 nm thick. The dissolved oxygen molecules are more easily reduced than the components of the electrolyte, leading to the formation of Li2 O as a stable passivation SEI film, which is expected to exhibit good charge-discharge features during the operation of the Li-O2 battery.