中低温固体氧化物燃料电池阴极界面改性研究进展

Progress of interface modification on cathode for low to intermediate temperature solid oxide fuel cell

在碳达峰、碳中和目标下,我国迫切需要提高煤炭的利用效率,降低CO_(2)排放。固体氧化物燃料电池(SOFC)是一种将碳氢燃料的化学能直接转换为电能的高效、环境友好的电化学转化装置。传统SOFC运行温度较高(800~1 000℃),长期高温运行会导致系统成本过高,关键材料性能衰减,以及组件间元素的互扩散、相反应等诸多问题。发展中低温SOFC已经成为未来SOFC技术发展的必然选择。然而,低温下,阴极缓慢的氧还原反应(ORR)动力学和不稳定性是制约SOFC技术发展的主要挑战。近年来,阴极界面改性作为一种提高中低温SOFC性能的有效策略得到广泛研究。通过设计不同的改性界面,可以显著加速阴极ORR动力学,有效地拓展阴极三相界面,提高阴极电催化活性,进而提高电池电化学性能;同时有效限制阴极颗粒长大,减少二次相生成,提高电池寿命。综述了界面改性的结构种类和特征(复合结构,膜状界面结构,骨架/表面涂覆结构),详细介绍了原子层沉积、脉冲激光沉积、湿法浸渍3种阴极界面改性技术,以及阴极界面改性对氧离子输运、氧还原反应活性以及稳定性的影响。最后,讨论了目前阴极界面改性技术存在的问题与挑战,以及克服这些问题的可能策略,为中低温SOFC阴极材料和结构的合理设计提供指导,为SOFC的实际应用奠定基础。

Under the goal of CO_(2) emissions peak and carbon neutrality,it urgently needs to improve the utilization efficiency of coal and reduce CO_(2) emissions in China.Solid oxide fuel cells( SOFC) are power generation devices that convert the chemical energy of fuel directly into electrical energy.The conventional SOFC generally requires high operating temperatures of about 800-1 000 ℃,which will cause severe problems such as increased system cost,performance degradation of the material,element diffusion and reaction between components,etc.Developing low to intermediate temperature SOFC is an inevitable choice for its application.However,the sluggish oxygen reduction reaction( ORR) process and instability at the cathode are the major challenges that limit the development of SOFC.Surface structural modifications of the cathode are considered to be the most effective strategy to improve performance.Designing surface structural modifications is believed to be the most effective strategy to accelerate cathodic ORR dynamics and cell performance,which can efficiently increase the triple-phase boundaries and provide more active sites.By surface modification,the coarsening of cathode particles and the phase insulation are restricted,and the cell life is improved.The techniques for cathode interface modification are introduced in detail.The structure types of modified interfaces( composite structure,membrane interface structure,skeleton/surface coating structure),three cathode interface modification technologies(atomic layer deposition,pulsed laser deposition and wet infiltration),and the effects of cathode interface modification on oxygen ion transport,catalytic activity,and stability are reviewed.Then the problems and challenges of cathode interface modification are discussed,and the possible strategies to overcome these problems are also discussed.It also provides valuable guidance for the reasonable design of cathode electrode material and structure and lay the foundation for the practical application of SOFC.