直接碳固体氧化物燃料电池研究进展:碳燃料和逆向Boudouard反应催化剂

Recent progress in direct carbon solid oxide fuel cells:Carbon fuels and reverse Boudouard reaction catalysts

直接碳固体氧化物燃料电池(direct carbon solid oxide fuel cells,DC-SOFCs)是一种能够将固体碳中的化学能直接转化为电能的新型能量转换装置,具有理论效率高、燃料来源广泛、成本低以及绿色环保等突出优势。根据DC-SOFC的工作原理,其运行过程是一个动力学控制步骤,即阳极侧CO的电化学氧化反应与碳燃料中逆向Boudouard反应的有效耦合保证了DC-SOFC的高效稳定运行。其中,速率相对较慢的逆向Boudouard反应是电池电化学性能的决定因素。因此,设计提高逆向Boudouard反应速率是促进DC-SOFC产业化进程的有效途径,也是发展趋势。国内外研究者采取了一系列措施来实现此目标,其中最简单有效的两种方法是:①在固体碳燃料中担载逆向Boudouard反应催化剂;②直接采用多孔结构且天然富含金属元素的生物质炭为燃料。基于近年来的前沿研究,本文综述了采用不同类型逆向Boudouard反应催化剂和碳燃料的DC-SOFCs最新研究进展,系统总结了DC-SOFCs的研究现状、面临的挑战和未来发展方向,以期为开发高性能、长寿命DCSOFCs提供有价值的参考。

Direct carbon solid oxide fuel cells(DC-SOFCs)are new-type energy conversion devices that directly convert the chemical energy of solid carbon into electricity.They have many advantages like high theoretical efficiency,wide range of fuel sources,low cost,and pollution.As per the working principle of DC-SOFCs,the cell operation is controlled by kinetics process.The effective coupling between the electrochemical oxidation reaction of CO in the anode and the reverse Boudouard reaction in carbon fuel ensures the efficient and stable operation of DC-SOFCs.The relatively slow reverse Boudouard reaction is the determining factor for the electrochemical performance of DC-SOFCs.Therefore,it is an effective way to promote the industrialization process of DC-SOFCs by improving the reverse Boudouard reaction.Much effort has been taken to achieve this goal.Among these,the simplest and effective means are to directly use a high-activity catalyst or the biochar due to their naturally existing catalyst and porous structure.Based on the frontier research in recent years,we review recent advances in the reverse Boudouard reaction catalysts and carbon fuels of DC-SOFCs in this paper.Moreover,the present status,challenges facing,and future directions of DC-SOFCs are also systematically summarized,in order to provide a more valuable reference for the development of high-performance and long-life DC-SOFCs.