Model of Performance of a Regenerative Hydrogen Chlorine Fuel Cell for Grid-Scale Electrical Energy Storage

We develop a model for a regenerative hydrogen-chlorine fuel cell (rHCFC) including four voltage loss mechanisms: hydrogen electrode activation, chlorine electrode activation, chlorine electrode mass transport, and ohmic loss through the membrane. The dependences of each of these losses as a function of two operating parameters, acid concentration and temperature; and five engineering parameters, exchange current densities at both electrodes, membrane thickness, acid diffusion layer thickness, and cell pressure, are explored. By examining this large parameter space, we predict the design target and ultimate limitations to the performance characteristics of this cell. We identify chlorine electrode activation as the dominant contribution to the loss for low current density, high-efficiency operation and membrane resistance as the dominant contribution to the loss at maximum galvanic power density. We conclude that, with further research, a more optimal cell could be developed that operates at greater than 90% voltage efficiency at current densities >1 A/cm(2) in both electrolytic and galvanic modes. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.030202jes] All rights reserved.