The other stage puts the sulfur dioxide and water into the electrolyzer to produce hydrogen and sulfuric acid. The presence of the sulfur dioxide reduces the voltage required across the electrodes to 0.8V per cell although the researchers are confident they can further reduce that to 0.6V. That brings the overall efficiency of the process to over fifty percent. SRNL is currently working on a larger multi-cell due to be completed next year. Longer term, SRNL is working on an integrated system that incorporates both stages of the hybrid sulfur process at the DOE's next generation nuclear plant in Idaho.
[Source: Department of Energy]