Monitoring self-discharge in a dual-ion battery using in situ Raman spectro-electrochemistry

A dual-ion battery employs two graphite electrodes to host cations and anions from the electrolyte. The high potential required to intercalate anions in graphite fully, typically > 5 V versus Li + /Li, triggers electrolyte decomposition and dissolution of the aluminium current collector. Such unw...

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Bibliographic Details
Published in:Materials research express 2023-11, Vol.10 (11), p.115506
Main Authors: Hassan, Ismail Yussuf, van Ekeren, Wessel W A, Kotronia, Antonia, Hahlin, Maria, Asfaw, Habtom D
Format: Article
Language:English
Subjects:
Additives
Anions
concentrated electrolyte
Decomposition reactions
Discharge
dual-ion battery
Electrochemistry
Electrodes
Electrolytes
Graphite
Open circuit voltage
operando gas pressure measurement
Pressure sensors
Raman spectra
Raman spectroscopy
Spectrum analysis
Stability analysis
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Summary:A dual-ion battery employs two graphite electrodes to host cations and anions from the electrolyte. The high potential required to intercalate anions in graphite fully, typically > 5 V versus Li + /Li, triggers electrolyte decomposition and dissolution of the aluminium current collector. Such unwanted reactions significantly aggravate self-discharge, leading to low energy efficiency and shorter cycle life. This study investigates changes in graphite structure during the intercalation of bis(fluorosulfonyl)imide (FSI) anion in 4 M LiFSI in ethyl methyl carbonate (EMC) and evaluates the stability of the associated FSI-intercalated graphite compounds using in situ Raman spectroscopy. The results highlight the critical importance of the duration the GICs remain in contact with the electrolyte, before the acquisition of the Raman spectra. Accordingly, the GICs with high FSI anion content exhibited only short-term stability and lost anions during open-circuit potential relaxation; only dilute GIC phases (stages ≥ IV) were sufficiently stable in the presence of the concentrated electrolyte. Furthermore, the formation of gaseous products during the charge–discharge cycles was verified using a 3-electrode cell with a pressure sensor. Future studies can adopt the experimental strategy developed in this work to assess the efficacy of electrolyte additives in mitigating self-discharge in DIBs.
ISSN:2053-1591
2053-1591
DOI:10.1088/2053-1591/ad0af2