Large-scale, cost-effective energy storage is highly desirable for balancing utility grid and renewable energy production. However, commercial scale demonstration of grid energy storage is generally lacking. Recently, we demonstrated a new bifunctional fuel-cell/battery hybrid system suited for stationary grid-scale energy storage. The new system is comprised of a reversible SOFC as the electrical charger/discharger and a redox-active metal/metal-oxide chemical bed as the energy store. During operation, the cathode of the system is constantly open to air, whereas the anode configuration defines the functionality of the system: power generation when the anode chamber is open to a fuel, and energy storage when the anode chamber is closed next to a neighboring metal/metal-oxide chemical bed.

The presentation highlights recent progress in performance evaluation and computational analysis of the fuel-cell/battery hybrid. These highlights include cycling performance in a temperature range of 500-600 ^oC and computational analysis of performance limiting factors. Strategies to achieve efficient and reversible hybrid system for simultaneous power generation and energy storage are proposed.