Cation effects on the electrochemistry of anions in polysulfide photoelectrochemical cells

Journal Article · Tue Dec 31 23:00:00 EST 1985 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2108540· OSTI ID:5837758

Licht, S; Tenne, R; Falisher, H; Manassen, J

Cations are shown to have significant effects, in aqueous alkali polysulfide solutions, on bulk electrolyte properties and on the electronics of polysulfide oxidation. Equinormal polysulfide solutions containing lithium, sodium, potassium, and cesium cations, respectively, were synthesized. The specific conductivity of these solutions exhibited an expected increase with increase in cation atomic size, namely, Li < Na < K < Cs. Ionic activity was also observed to follow the same trend, although generally accepted models of ionic activity predict that this parameter will increase with decreasing atomic size. Polarization losses increase in the order Cs < K < Na < Li for polysulfide oxidation and reduction at an electrocatalytic Cu/sub 2/S electrode. Variation of alkali cation in aqueous polysulfide electrolytes is shown to significantly modify current/voltage, stability, photocurrent/light intensity, normalized ratio, and Mott-Schottky characteristics of single-crystal cadmium chalcogenide photoelectrochemical cells (PEC's). The extent of PEC enhancement exhibited the observed trend Cs > K > Na > Li for alkali polysulfide electrolyte. Under intense illumination, the PEC containing cesium electrolyte, when compared to the lithium electrolyte, exhibited considerably enhanced conversion efficiences and, under accelerated testing conditions, increased the PEC lifetime by several orders of magnitude. The bulk electrolyte, inert electrode, and photoactive electrode results are consistent with a model that is presented illustrating cation effects on ion association, mobility, and adsorption in concentrated solutions.

• Research Organization: Dept. of Materials Research, The Weizmann Inst. of Science, Rehovot 76100
• OSTI ID: 5837758
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 133:1; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
&amp; Thermochemical Conversion-- (1980-)
ADSORPTION
ALKALI METALS
ANIONS
AQUEOUS SOLUTIONS
CATIONS
CESIUM
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
COPPER COMPOUNDS
COPPER SULFIDES
CURRENTS
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTROCHEMICAL CELLS
ELECTROCHEMISTRY
ELECTRODES
ELECTROLYTES
ELEMENTS
EQUIPMENT
IONS
LITHIUM
METALS
MIXTURES
OXIDATION
PHOTOCURRENTS
PHOTOELECTROCHEMICAL CELLS
PHYSICAL PROPERTIES
POLARIZATION
POTASSIUM
REDUCTION
SERVICE LIFE
SIZE
SODIUM
SOLAR EQUIPMENT
SOLUTIONS
SORPTION
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS