부산대학교 도서관

The current status of electrodes for the NASA Redox energy storage system based on iron and chromium chloride reactants is discussed. Difficulties in making well-behaved electrodes for the chromium side of the flow cell have been largely overcome. The physical properties of several lots of felt were determined. Refined procedures were developed for evaluating electrode performance in lab-scale cells. Experimental procedures for evaluating electrodes by cyclic voltammetry are described which minimize the IR losses due to the high internal resistance in the felt (distributed resistance). Improved methods for preparing electrodes were discovered which reduced the coevolution of hydrogen at the chromium electrode and eliminated the drop in voltage on discharge occasionally seen with previous electrodes. Single cells of 0.33 ft/sup 2/ area with improved membranes and electrodes are operating at over 80 percent voltage efficiency and coulombic efficiencies of over 98 percent at current densities of 16 to 20 amp/ft/sup 2/.