Study on a single flow acid Cd-chloranil battery

This paper describes a novel redox flow battery-single flow acid Cd-chloranil battery. The electrolyte of this battery for both negative electrode and positive electrode is the aqueous intermixture of H2SO4-(NH4)(2)SO4-CdSO4, the negative electrode is inert metal such as copper foil, and the positive electrode is an insoluble organic material, tetrachloro-p-benzoquinone (chloranil). Typically, the electrolyte is continuously Circulated to pass though the cells by means of a single pump as the battery is on duty. There is no requirement for a membrane. TetrachIoro-p-benzo-hydroquinone is oxidized to chloranil at positive electrode and the cadmium ions is reduced to cadmium and electroplated onto the negative electrode during charge. The reverse occurs during discharge. Results obtained with a small laboratory cell show that high efficiencies can be achieved with an average coulombic efficiency of 99% and energy efficiency of 82% over 100 cycles at the current density of 10 mA cm(-2). (c) 2009 Elsevier B.V. All rights reserved.