THE EFFECTS OF CONCENTRATION ON POLARIZATION CAPACITY AND POLARIZATION RESISTANCE IN FERROYANIDE-FERRICYANIDE CELLS WITH PLATINUM ELECTRODES
Abstract
Resistance and capacitance measurements were made with a modification of the bridge described by Shaw and Remick (J. Electrochem. Soc. 97:324, 1950). The true electrolytic resistance and the polarization resistance, R sub Delta, were determined graphically. To clean the Pt cathodes, 3 v was used with an electrode separation of about 1.8 cm. The electrodes were immersed in an alkaline cyanide solution and cleaned anodically for 2 min and cathodically for 4 min. After 3 cycles, they were washed with distilled water and then with a portion of the cell solution and immersed in the cell. Steady readings were obtained after 30 min immersion. A tentative explanation is given for the hysteresis observed when the electrodes were subjected to high current densities. The effect of current density on capacitance and resistance and the cell voltage-current relationship are discussed. The reproducibility of electrodes was established. The equivalent series capacitance, Cs, increased slightly with ionic strength and markedly with depolarizer concentration. R sub Delta decreased greatly with an increase in ionic strength. Q-dispersion measurements showed that a surface layer left on the electrode by the cleaning process contributes to the electrode layer resistance, R sub 1, and that R sub 1 is always positive and is directly proportional to depolarizer concentration and inversely proportional to the supporting electrolytic concentration. The double- layer capacity was determined for supporting electrode measurements. Semiquantitative and qualitative checks were made of Grahame's theory.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 15, 1953
- Accession Number
- AD0011254
Entities
People
- A. E. Remick
- Herbert W. Mccormick
Organizations
- Wayne State University