Recent advances in high-temperature carbon-air fuel cells

The development of environmentally clean and energy-efficient coal-based power plants is of strategic importance to meet the increasing demand for more energy and clean air in the future. Carbon-air fuel cells (CAFCs) are a promising class of clean, efficient and sustainable power generators fueled by an abundant, cheap and sometimes renewable fuel source - coal, biomass, municipal waste, and other forms of solid carbons, with low emissions of CO2, NOx, SOx and VOCs. Because of the inherent thermodynamic and environmental advantages, CAFCs have garnered much interest in recent decades. In this article, we review recent advances in material development for catalysts/anodes and novel designs of various types of CAFCs. Fundamental understanding of the mechanisms and rate-limiting steps in carbon conversion is also discussed in detail. Finally, the review is concluded with promises and challenges of CAFCs.