The Fall Semester Seminar
■ Topic : Operation of Rechargeable Li-O2 Cells without CO2 Evolution
■ Speaker : Prof. Seok Ju Kang (Energy and Chemical Eng., UNIST)
■ Date & Time : October 27 (Tue), 16:00
■ Venue : KAIST Applied Engineering B/D(W1), Multimedia Lecture Hall (1st Floor)
■ Abstract : The Li-O2 battery has attracted considerable because of their high capacity and potential application in electronic vehicle. However, so far, Stability of component materials against parasitic reactions is a paramount challenge, in particular carbon dioxide (CO2) evolution has been an unavoidable event for operation of Li-O2 cells. The origin of CO2 evolution has been understood as the oxidative decomposition of carbonates which are formed by decomposition of both electrode carbon and electrolyte solvent. While carbon has been used as a common electrode material for Li-O2 cells, its reactivity toward oxidation and catalytic role for other parasitic reactions make it challenging to be used for practical applications. This talk will present a simple but potent approach to eliminate carbon dioxide evolution by using an ionic solvation. We show that the solvate leads to deactivation of the carbon against parasitic reactions by electrochemical doping of nitrogen into carbon. Detailed methods and mechanistic studies will be discussed throughout the talk.