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Title: Room temperature inorganic ``quasi-molten salts`` as alkali-metal electrolytes

Abstract

Room temperature inorganic liquids of high ionic conductivity have been prepared by reacting Lewis acid AlCl with sulfonyl chlorides. The mechanism is not clear at this time since a crystal structure study of the 1:1 complex with CH{sub 3}SO{sub 2}Cl (T{sub m} = 30 C) is not consistent with a simple chloride transfer to create AlClO{sub 4}{sup {minus}} anions. The liquid is in a state somewhere between ionic and molecular. A new term quasi-molten salt is adopted to describe this state. A comparably conducting liquid can be made using BCL{sub 3} in place of AlCl{sub 3}. Unlike their organic counterparts based on ammonium cations (e.g., pyridinium or imidazolium) which reduce in the presence of alkali metals, this inorganic class of cation shows great stability against electrochemical reduction (ca. {minus}1.0 V vs. Li{sup +}/Li), with the useful consequence that reversible lithium and sodium metal deposition/stripping can be supported. The electrochemical window for these quasi-salts with AlCl{sub 3} ranges up to 5.0 V, and their room temperature conductivities exceed 10{sup {minus}4} S/cm. They dissolve lithium and sodium tetrachloroaluminates up to mole fraction {approximately} 0.6 at 100 C and intermediate compositions are permanently stable at ambient. The resultant lithium or sodium salt solutionsmore » exhibit electrochemical windows of 4.5--5.0 V vs. Li{sup +}/Li or Na{sup +}/Na and show room temperature conductivities of 10{sup {minus}3.0}--10{sup {minus}2.5} S/cm. In preliminary charge/discharge tests, the cell Li/``quasi-ionic liquid electrolyte``/Li{sub 1+x}Mn{sub 2}O{sub 4} showed a discharge capacity of ca. 110 mAh/(g of cathode) and sustained 80% of the initial capacity after 60 cycles, indicating that these quasi-molten salt-based electrolytes are promising candidates for alkali-metal batteries.« less

Authors:
; ;  [1]
  1. Arizona State Univ., Tempe, AZ (United States). Dept. of Chemistry
Publication Date:
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
428164
DOE Contract Number:  
FG02-89ER45398
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 143; Journal Issue: 11; Other Information: PBD: Nov 1996
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; LITHIUM-SULFUR BATTERIES; ELECTROLYTES; SODIUM-SULFUR BATTERIES; ALUMINIUM CHLORIDES; THIONYL CHLORIDES; LITHIUM; SODIUM; ELECTROCHEMISTRY; VOLTAGE DROP; BATTERY CHARGING

Citation Formats

Xu, K, Zhang, S, and Angell, C A. Room temperature inorganic ``quasi-molten salts`` as alkali-metal electrolytes. United States: N. p., 1996. Web. doi:10.1149/1.1837251.
Xu, K, Zhang, S, & Angell, C A. Room temperature inorganic ``quasi-molten salts`` as alkali-metal electrolytes. United States. doi:10.1149/1.1837251.
Xu, K, Zhang, S, and Angell, C A. Fri . "Room temperature inorganic ``quasi-molten salts`` as alkali-metal electrolytes". United States. doi:10.1149/1.1837251.
@article{osti_428164,
title = {Room temperature inorganic ``quasi-molten salts`` as alkali-metal electrolytes},
author = {Xu, K and Zhang, S and Angell, C A},
abstractNote = {Room temperature inorganic liquids of high ionic conductivity have been prepared by reacting Lewis acid AlCl with sulfonyl chlorides. The mechanism is not clear at this time since a crystal structure study of the 1:1 complex with CH{sub 3}SO{sub 2}Cl (T{sub m} = 30 C) is not consistent with a simple chloride transfer to create AlClO{sub 4}{sup {minus}} anions. The liquid is in a state somewhere between ionic and molecular. A new term quasi-molten salt is adopted to describe this state. A comparably conducting liquid can be made using BCL{sub 3} in place of AlCl{sub 3}. Unlike their organic counterparts based on ammonium cations (e.g., pyridinium or imidazolium) which reduce in the presence of alkali metals, this inorganic class of cation shows great stability against electrochemical reduction (ca. {minus}1.0 V vs. Li{sup +}/Li), with the useful consequence that reversible lithium and sodium metal deposition/stripping can be supported. The electrochemical window for these quasi-salts with AlCl{sub 3} ranges up to 5.0 V, and their room temperature conductivities exceed 10{sup {minus}4} S/cm. They dissolve lithium and sodium tetrachloroaluminates up to mole fraction {approximately} 0.6 at 100 C and intermediate compositions are permanently stable at ambient. The resultant lithium or sodium salt solutions exhibit electrochemical windows of 4.5--5.0 V vs. Li{sup +}/Li or Na{sup +}/Na and show room temperature conductivities of 10{sup {minus}3.0}--10{sup {minus}2.5} S/cm. In preliminary charge/discharge tests, the cell Li/``quasi-ionic liquid electrolyte``/Li{sub 1+x}Mn{sub 2}O{sub 4} showed a discharge capacity of ca. 110 mAh/(g of cathode) and sustained 80% of the initial capacity after 60 cycles, indicating that these quasi-molten salt-based electrolytes are promising candidates for alkali-metal batteries.},
doi = {10.1149/1.1837251},
journal = {Journal of the Electrochemical Society},
number = 11,
volume = 143,
place = {United States},
year = {1996},
month = {11}
}