Current-voltage characteristics of an electrolytic cell

• Grant number: 06/00866-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2006
• End date: May 31, 2009
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Antonio Martins Figueiredo Neto
• Grantee: Fernando Batalioto
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The dependence of the electrical current on the applied voltage to a cell of a weak electrolyte is considered. We generalize a previous model relevant to dieletric media in which the electrical conductivity has an ionic origin and the electrodes are perflectly blocking. We show that a linear dependence of the current on the applied voltage can be interpreted by assuming that two types of ions are present in the electrolyte, and that the electrodes behave as perfectly blocking for one type, and perfectly ohomic for the other type of ions. Another mechanism able to justify the linear dependence of the current on the applied voltage is based on the assumption that the dissociation constant for the ions formation depends on the actual electric field in the sample. This is also discussed.