Investigation of the process of formation of a chemical current source in the «red-ox» Fe(II) – Fe(III) system in a sulfuric acid environment

Abstract

Among the technologies designed to save energy, flow-through batteries deserve special attention. Their principle of operation is based on the use of systems of variably valent ions. The aim of the work is to create a chemical current source based on the use of the "red – ox" Fe(II)/Fe(III) system and to determine the patterns of formation of electromotive force (EMF) and short-circuit current (SCC) in acidic solutions depending on the concentration of ions. The experiments are carried out by measuring the EMF formed between graphite electrodes and SCC. A special installation has been assembled, consisting of an electrolyzer with separated electrode spaces, an ammeter, a voltmeter and graphite electrodes. Acidified solutions of iron (II) and iron (III) sulfates served as the electrolyte. In an electrolyzer, the electrode spaces of which are separated by an anionite membrane, when one space is filled with iron (II) sulfate and the other with iron (III) sulfate, an EMF occurs between graphite electrodes. When making contact between graphite electrodes, iron (II) oxidation occurs in the first electrode space, and iron (III) reduction occurs in the second. A chemical current source is being formed. At a concentration of iron (III) equal to 20 g/l, a change in the concentration of iron (II) in the range of 1-40 g / l contributes to a shift in the potential of the graphite electrode to negative values. At a concentration of Fe(III) equal to 1 g/l, the potential value is 509 mV, and at 40 g / l – 475 mV. At a constant concentration of iron (II), the addition of Fe(III) leads to a shift in the EMF value to the right. It was found that as a result of these changes, an increase in EMF and SCC is observed.