Maximizing plating density and efficiency for a negative deposition reaction in a flow battery

Flow batteries utilizing a plating reaction as the negative reaction are limited in energy capacity by the available void area in the cell stack. Large scale energy storage applications necessitate maximizing the plating density within the flow battery. Six porous negative electrode configurations using conductive and non-conductive materials are considered for use in a hybrid flow battery. Plating results using a Cu- Fe sulfate chemistry demonstrated a plating density in a carbon felt electrode (145 mAh cm(-2) at 40 mA cm(-2)). Two layered electrode configurations were able to achieve 150 mAh cm(-2) of plating density: carbon felt with non-conductive felt, and carbon felt-Daramic-carbon felt. Both electrode designs were tested with the all-iron chemistry using shallow charge/discharge cycles. The carbon felt with non-conducting felt electrode configuration maintained a voltaic efficiency of 81% over six cycles. (C) 2014 Elsevier B.V. All rights reserved.