High-Performance and Durable Reversible Fuel Cells Based on Proton Conductors

Abstract

A reversible fuel cell (RFC) can operate both in a fuel cell mode (to convert chemical fuels to electricity) and in an electrolysis mode (to produce hydrogen and carbon-containing fuels from electrolysis of water and carbon dioxide, respectively). RFCs have potential to be one of the most efficient and low-cost options for co-located energy storage and power generation. To date, oxide ion conductors (such as zirconia-based electrolytes) have been widely studied for RFCs. In comparison, RFCs based on proton conductors have several advantages, including operation at intermediate temperatures (400–600 °C), simplified system design, reduced cost, and enhanced durability due to the generation ‘dry’ hydrogen in the negative electrode compartment. In this presentation, we will report our recent progress in the development of high-performance and durable RFCs based on proton conductors. When operated in the fuel cell mode, the RFC achieves peak power densities of about 1.0 and 1.5 W cm-2 at 600 and 650 °C, respectively. When operated in both the fuel cell mode and the electrolysis mode, the RFC demonstrates a roundtrip efficiency of greater than 70% at 1 A cm-2 and 650 °C while maintain excellent stability (without obvious degradation in performance for continuous operation of more than 400 h).