121st General Meeting of the KCS

Type Poster Presentation
Area Electrochemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code ELEC.P-579
Subject The Role of Solid Electrolyte Interphase (SEI) at Sodium Metal Electrode for Sodium-Oxygen (Na-O2) Batteries
Authors Younguk Jung, Sujung Kim, Hye Ryung Byon*
Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
Abstract Metal-oxygen batteries have been paid attention to one of the promising next-generation batteries owing to their higher energy densities than current lithium-ion batteries. In particular, sodium-oxygen (Na-O2) batteries are a promising candidate applied for electric vehicles, because they provide far higher round-trip efficiency than lithium-oxygen (Li-O2) batteries. Unlike in Li-O2 batteries, the O2- may be stable with Na+ ion caused by favorable soft base and soft acid interaction. The main discharge product of sodium superoxide (NaO2) and insignificant amount of side product in Na-O2 cells demonstrate highly stable superoxide species at the positive electrode side. Nevertheless, cycling stability has still underperformed in Na-O2 cells, which have not as yet been fully understood. Here we improve cycling performance of Na-O2 cells by increasing stability of negative electrode, Na metal. Na metal is highly reactive and easily forms solid electrolyte interphase (SEI) layer through chemical reduction of electrolyte solution. We investigated the stability and composition of SEI layer on Na metal and its effect on Na-O2 battery performance by differentiating the electrolyte. X-ray photoelectron spectroscopy and online-electrochemical mass spectroscopy was used to analyze the component of SEI layer on Na metal.
E-mail zxvc45@kaist.ac.kr