High-voltage electrodes based on, for example, LiNi Mn 0 (LNMO) active material require oxidative stability of inactive materials up to 4.95 V vs. Li|Li .
View Article and Find Full Text PDFIncreasing the operation voltage of electrochemical energy storage devices is a viable measure to realize higher specific energies and energy densities. A sufficient oxidative stability of electrolytes is the predominant requirement for successful high voltage applicability. The common method to investigate oxidative stability of LIB electrolytes is related to determination of the electrochemical stability window (ESW), on e.
View Article and Find Full Text PDFThe inability of imide salts to form a sufficiently effective passivation layer on aluminum current collectors is one of the main obstacles that limit their broad application in electrochemical energy-storage systems. However, under certain circumstances, the use of electrolytes with imide electrolyte salts in combination with the aluminum current collector is possible. In this contribution, the stability of the aluminum current collector in electrolytes containing either lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) or lithium fluorosulfonyl-(trifluoromethanesulfonyl) imide (LiFTFSI) as conductive salt was investigated by electrochemical techniques, that is, cyclic voltammetry (CV) and chronocoulometry (CC) in either room-temperature ionic liquids or in ethyl methyl sulfone.
View Article and Find Full Text PDFBatteries based on cathode materials that operate at high cathode potentials, such as LiNi Mn O (LNMO), in lithium-ion batteries or graphitic carbons in dual-ion batteries suffer from anodic dissolution of the aluminum (Al) current collector in organic solvent-based electrolytes based on imide salts, such as lithium bis(trifluoromethanesulfonyl) imide (LiTFSI). In this work, we developed a protective surface modification for the Al current collector by applying ceramic coatings of chromium nitride (Cr N) and studied the anodic Al dissolution behavior. By magnetron sputter deposition, two different coating types, which differ in their composition according to the CrN and Cr N phases, were prepared and characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and their electronic conductivity.
View Article and Find Full Text PDFDiverse LiPF hydrolysis products evolve during lithium-ion battery cell operation at elevated operation temperatures and high operation voltages. However, their impact on the formation and stability of the electrode/electrolyte interfaces is not yet investigated and understood. In this work, literature-known hydrolysis products of LiPF dimethyl fluorophosphate (DMFP) and diethyl fluorophosphate (DEFP) were synthesized and characterized.
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