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130th General Meeting of Korean Chemical Society Additive Effect on Solvation Structure in Organic Liquid Electrolytes

Submission Date :
8 / 2 / 2022 , 15 : 51 : 09
Abstract Number :
Presenting Type:
Poster Presentation
Presenting Area :
Physical Chemistry
Authors :
Jiyeon Yang, Kyungwon Kwak*, Minhaeng Cho*
Department of Chemistry, Korea University, Korea
Assigned Code :
Presenting Time :
Organic carbonates are widely used as electrolytes for lithium-ion batteries (LIBs), but their low electrochemical stability causes many problems. It is now well established that electrolyte additives significantly improve the safety of LIBs. However, the solvation nature of Li-ion with additives has remained unclear. It is crucial to study solvation structure which is the initial state of reaction on the electrode to understand the overall battery reaction. We anticipate the effect of additives on solvation structure by coordination number (CN) that is determined by using infrared (IR) spectroscopy. It is analyzed using additives such as ethylene sulfite (ES) that are commonly used. The CN shows a monotonous decrease as the ES ratio is increased. The S=O stretching mode was observed and compared to the S=O peak that arises due to the interaction of Li-ion and ES. The contact ion-pair (CIP) concentration is confirmed by Raman spectroscopy, and there is no CIP concentration change. It validates that not the CIP but the additive affected the decrease of CN. It suggests that the additives participate in the solvation shell. Furthermore, CN varies depending on the dipole moment of the additive. The more additive dipole moment is increased, the more CN is decreased. It could estimate the degree of additive effects on the electrochemical property of LIB.