Low temperature lithium/sulfur secondary battery. Semiannual progress report, December 1, 1974--June 1, 1975. [Development of dissolved sulfur cathode operable at ambient temperatures]
The objective of this program is to develop a dissolved sulfur cathode which can be repeatably charged and discharged with minimal degradation and which is compatible with a Li anode. The redox behavior of dilute S/sub 8/, 0.1--1M LiClO/sub 4/ solutions in dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), tetrahydrofuran (THF), propylene carbonate (PC), ..gamma..-butyrolactone (BL), sulfolane (SL), methyl acetate (MA) and pyridine was investigated. S/sub 8/ and S/sub 8//sup - -/ reductions occur at more positive potentials and the redox reactions are more reversible in DMSO and DMF than in the other solvents. Some evidence exists for the precipitation of Li/sub 2/S/sub x/ species on Au and Pt working electrodes (but not on C). The electrochemical behavior of Li/sub 2/S/sub x/ solutions was examined. Cyclic voltammograms of polysulfide solutions in DMSO showed generally reductions at more negative potentials and oxidations at more positive potentials than those for S/sub 8/ solutions. The polysulfide and S/sub 8/ voltammograms in THF were more similar. Steady-state current potential curves of DMSO--Li/sub 2/S/sub x/ solutions generally revealed no sizeable reduction currents positive of approximately 1.5 V vs. Li. Galvanostatic discharge of Li/sub 2/S/sub x/ solutions occurs between 1.0 and 2.0 V. Recharge (with a 4.0 V limit) was possible in THF, BL and DMSO. The fact that steady-state discharge in these solutions, andparticularly in DMSO--Li/sub 2/S/sub x/ solutions, occurs at more negative potentials than indicated by cyclic voltammograms suggests a degradation of active species in solution following initial reduction. If the species S/sub 3//sup -/ is more difficult to reduce than S/sup - -//sub x/, then solvents or electrolyte additives which stabilize S/sup - -//sub x/ in preference to S/sub 3//sup -/ would be most favorable for use in a practical battery. 23 figures, 8 tables.
- Research Organization:
- Eic, Inc., Newton, MA (USA)
- DOE Contract Number:
- EY-76-C-02-2520
- OSTI ID:
- 7123165
- Report Number(s):
- COO-2520-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LITHIUM-SULFUR BATTERIES
CATHODES
CARBONIC ACID ESTERS
DMSO
FURANS
LACTONES
LITHIUM SULFIDES
MEDIUM TEMPERATURE
REDOX REACTIONS
SULFIDES
ALKALI METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTRIC BATTERIES
ELECTROCHEMICAL CELLS
ELECTRODES
ENERGY STORAGE SYSTEMS
ESTERS
HETEROCYCLIC COMPOUNDS
LITHIUM COMPOUNDS
METAL-NONMETAL BATTERIES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
SULFOXIDES
SULFUR COMPOUNDS
250903* - Energy Storage- Batteries- Materials
Components
& Auxiliaries