Improving Electrochemical Performance at Graphite Negative Electrodes in Concentrated Electrolyte Solutions by Addition of 1,2-Dichloroethane

In concentrated propylene carbonate (PC)-based electrolyte solutions, reversible lithium intercalation and de-intercalation occur at graphite negative electrodes because of the low solvation number. However, concentrated electrolyte solutions have low ionic conductivity due to their high viscosity,...

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Bibliographic Details
Published in:Applied sciences 2019-11, Vol.9 (21), p.4647
Main Authors: Song, Hee-Youb, Jung, Moon-Hyung, Jeong, Soon-Ki
Format: Article
Language:English
Subjects:
concentrated electrolyte solutions
Decomposition
Dichloroethane
Electrochemical analysis
Electrochemistry
Electrodes
Graphite
Intercalation
Ion currents
Ions
Lithium
lithium-graphite intercalation compounds
Lithium-ion batteries
Personal computers
Propylene
Raman spectroscopy
solid electrolyte interphase
Solid electrolytes
Solvation
solvation structures
Solvents
Spectrum analysis
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Summary:In concentrated propylene carbonate (PC)-based electrolyte solutions, reversible lithium intercalation and de-intercalation occur at graphite negative electrodes because of the low solvation number. However, concentrated electrolyte solutions have low ionic conductivity due to their high viscosity, which leads to poor electrochemical performance in lithium-ion batteries. Therefore, we investigated the effect of the addition of 1,2-dichloroethane (DCE), a co-solvent with low electron-donating ability, on the electrochemical properties of graphite in a concentrated PC-based electrolyte solution. An effective solid electrolyte interphase (SEI) was formed, and lithium intercalation into graphite occurred in the concentrated PC-based electrolyte solutions containing various amounts of DCE, while the reversible capacity improved. Raman spectroscopy results confirmed that the solvation structure of the lithium ions, which allows for effective SEI formation, was maintained despite the decrease in the total molality of LiPF6 by the addition of DCE. These results suggest that the addition of a co-solvent with low electron-donating ability is an effective strategy for improving the electrochemical performance in concentrated electrolyte solutions.
ISSN:2076-3417
2076-3417
DOI:10.3390/app9214647