title: Improved Interfacial Properties of MCMB Electrode by 1-(Trimethylsilyl)imidazole as New Electrolyte Additive To Suppress LiPF6Decomposition.
abstract: Trace water content in the electrolyte causes the degradation of LiPF6, and the decomposed products further react with water to produce HF, which alters the surface of anode and cathode. As a result, the reaction of HF and the deposition of decomposed products on electrode surface cause significant capacity fading of cells. Avoiding these phenomena is crucial for lithium ion batteries. Considering the Lewis-base feature of the N-Si bond, 1-(trimethylsilyl)imidazole (1-TMSI) is proposed as a novel water scavenging electrolyte additive to suppress LiPF6decomposition. The scavenging ability of 1-TMSI and beneficiary interfacial chemistry between the MCMB electrode and electrolyte are studied through a combination of experiments and density functional theory (DFT) calculations. NMR analysis indicated that LiPF6decomposition by water was effectively suppressed in the presence of 0.2 vol % 1-TMSI. XPS surface analysis of MCMB electrode showed that the presence of 1-TMSI reduced deposition of ionic insulating products caused by LiPF6decomposition. The results showed that the cells with 1-TMSI additive have better performance than the cell without 1-TMSI by facilitating the formation of solid-electrolyte interphase (SEI) layer with better ionic conductivity. It is hoped that the work can contribute to the understanding of SEI and the development of electrolyte additives for prolonged cycle life with improved performance.
authors.forename: Aselefech Sorsa
authors.initials: AS
authors.lastname: Wotango
authors.forename: Wei-Nien
authors.identifier: http://orcid.org/0000-0003-1494-2675
authors.initials: WN
authors.lastname: Su
authors.forename: Ermias Girma
authors.initials: EG
authors.lastname: Leggesse
authors.forename: Atetegeb Meazah
authors.initials: AM
authors.lastname: Haregewoin
authors.forename: Ming-Hsien
authors.initials: MH
authors.lastname: Lin
authors.forename: Tilahun Awoke
authors.initials: TA
authors.lastname: Zegeye
authors.forename: Ju-Hsiang
authors.initials: JH
authors.lastname: Cheng
authors.affiliation: National Synchrotron Radiation Research Center, Hsin-chu, Taiwan.
authors.forename: Bing-Joe
authors.identifier: http://orcid.org/0000-0002-3873-2149
authors.initials: BJ
authors.lastname: Hwang
keywords: 1-(trimethylsilyl)imidazole; LiPF6 decomposition; MCMB electrode; electrolyte additive; water scavenger