Room temperature molten salt electrolytes for photoelectrochemical applications
Mixtures of aluminum chloride (AlCl/sub 3/) with triethylammonium chloride 1,6-ethyl lutidinium bromide (EtluBr), tert-butyl pyridinium bromide (BPBr), and dialkyl imidazolium chloride (R/sub 2/ImCl), in certain molar ratios yielded ionic liquids at room temperature which were studied with respect to their applicability as electrolytes in photoelectrochemical (PEC) cells. Background voltammograms were obtained for these electrolytes on carbon and n-GaAs electrodes. The anodic stability limit was found to be enhanced on n-GaAs relative to carbon in all cases. The cathodic decomposition potential of the electrolyte showed a smaller positive shift on n-GaAs with the exception of the 3:1 AlCl/sub 3/ BPBr electrolyte. The difference in electrolyte stability behavior on carbon and n-GaAs is interpreted in terms of carrier density effects. Cyclic voltammograms were compared on carbon in the various electrolytes for a model redox system comprising the ferrocene/ferricenium couple. The separation of the cathodic and anodic waves in all the cases was consistent with a quasi-reversible redox behavior--the most sluggish electron transfer being observed in the case of the 3:1 AlCl/sub 3/-BpBr electrolyte. Capacitance-voltage measurements were made on n-GaAs electrodes in contact with the various electrolytes. Flatband-potentials (V /SUB fb/) were deduced from these data using Mott-Schottky plots. The implications of this result for PEC applications and the role of specific ion adsorption of electrolyte species on the electrostatic aspects of the n-GaAs/molten salt electrolyte-interface are discussed with the aid of energy band diagrams.
- Research Organization:
- Department of Electrical Engineering, Colorado State University, Fort Collins, CO 80523
- OSTI ID:
- 5994976
- Journal Information:
- J. Sol. Energy Eng.; (United States), Vol. 104:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
MOLTEN SALTS
ELECTROLYTES
PHOTOELECTROCHEMICAL CELLS
ALUMINIUM CHLORIDES
AMMONIUM CHLORIDES
ANODES
CAPACITANCE
CARBON
ELECTRON TRANSFER
REDOX REACTIONS
STABILITY
TEMPERATURE DEPENDENCE
VOLTAMETRY
ALUMINIUM COMPOUNDS
AMMONIUM COMPOUNDS
AMMONIUM HALIDES
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTRODES
ELEMENTS
EQUIPMENT
HALIDES
HALOGEN COMPOUNDS
NONMETALS
PHYSICAL PROPERTIES
SALTS
SOLAR EQUIPMENT
400400* - Electrochemistry