The Lewis acidity of room temperature chloroaluminate molten salts buffered with sodium chloride

Journal Article · Mon Nov 01 00:00:00 EST 1993 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2220993· OSTI ID:5696239

Riechel, T L; Wilkes, J S ^[1]

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1. Air Force Academy, CO (United States). Frank J. Seiler Research Lab.

Lewis neutral room temperature chloroaluminate molten salts made by mixing 1-methyl-3-ethylimidazolium chloride (MEIC1) and aluminum chloride are being investigated as possible batter electrolytes because of their wide potential windows. The electrochemistry of a NaCl-buffered, MEIC1/AlCl[sub 3] melt was studied using Pt and W electrodes. When excess NaCl is added to an N = 0.55 melt (N = the mole fraction AlCl[sub 3]) a neutral melt results, saturated with NaCl. The cyclic voltammetry shows several small overlapping reduction peaks which lead to a small, but distinct oxidation peak about [minus]0.1V (vs an Al/Al[sup 3+] N = 0.6 melt reference). Comparison to the voltammogram of an N = 0.5002 melt (no NaCl) suggests that the oxidation process is aluminum stripping. A series of plating and stripping experiments and scanning electron microscopic (SEM) examination of the electrode surfaces verify this. The presence of the Al stripping peak in the voltammogram of the buffered melt means that this melt is still slightly Lewis acidic even when saturated with NaCl. The concentration of Al[sub 2]Cl[sub 7][sup [minus]] in the buffered melt is estimated to be 2.8 [times] 10[sup [minus]3]M. This is considerably higher than the calculated equilibrium concentration for Al[sub 2][sub 7][sup [minus]] of 4.5 [times] 10[sup [minus]8]M corresponding to a truly Lewis natural melt.

• OSTI ID: 5696239
• Journal Information: Journal of the Electrochemical Society; (United States), Vol. 140:11; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
37 INORGANIC
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ELECTRIC BATTERIES
ELECTROLYTES
MOLTEN SALTS
EXPERIMENTAL DATA
PH VALUE
ALUMINIUM COMPOUNDS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
DATA
ELECTROCHEMICAL CELLS
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HALOGEN COMPOUNDS
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NUMERICAL DATA
SALTS
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