Review of anodic reactions in hydrocarbon fueled solid oxide fuel cells and strategies to improve anode performance and stability

Direct utilization of hydrocarbon fuels in solid oxide fuel cells (SOFCs) has drawn special attention for high energy conversion efficiency, low cost, and simple devices. However, when fueled with hydrocarbons, SOFCs encountered great difficulty in both performance and stability, which should be attributed to the sluggish hydrocarbon oxidizing reactions, the severe carbon deposition reactions, and the possible sulfur poisoning reactions in the anode. This review summarizes potential anode reactions in hydrocarbon-fueled SOFCs and discusses the possible anode deactivation mechanisms. Further, various strategies to improve the anode performance and stability are reviewed, including substituting alloys or increasing oxide basicity for nickel-based anodes, adopting oxide anodes, and adding catalyst layers. The advantages and challenges of each strategy are discussed. Special attention is paid on properties and models of novel oxide anodes, of which nano-metal catalysts are in-situ exsolved. The publications concerning SOFC anodes, mainly in recent 5 years, are listed and compared in this article.