  We report the performance of a hydrogen-chlorine electrochemical cell with a
chlorine electrode employing a low precious metal content alloy oxide
electrocatalyst for the chlorine electrode: (Ru_0.09Co_0.91)_3O_4. The cell
employs a commercial hydrogen fuel cell electrode and transports protons
through a Nafion membrane in both galvanic and electrolytic mode. The peak
galvanic power density exceeds 1 W cm^-2, which is twice previous literature
values. The precious metal loading of the chlorine electrode is below 0.15 mg
Ru cm^-2. Virtually no activation losses are observed, allowing the cell to run
at nearly 0.4 W cm^-2 at 90% voltage efficiency. We report the effects of fluid
pressure, electrolyte acid concentration, and hydrogen-side humidification on
overall cell performance and efficiency. A comparison of our results to the
model of Rugolo et al. [Rugolo et al., J. Electrochem. Soc., 2012, 159, B133]
points out directions for further performance enhancement. The performance
reported here gives these devices promise for applications in carbon
sequestration and grid-scale electrical energy storage.
