水蒸气电解制氢固体氧化物电解池空气电极研究进展

Progress of Air Electrode in Solid Oxide Electrolytic Cell for Hydrogen Production through Steam Electrolysis

固体氧化物电解池(Solid Oxide Electrolysis Cell, SOEC)是一种可以直接将电能转换为化学能储存在燃料气体中的能源转换装置,具有很高的能量转换效率。SOEC和固体氧化物燃料电池(Solid Oxide Fuel Cell, SOFC)的组合可以解决风能、太阳能等新兴的清洁能源间歇式发电的问题,在发电量达到峰值时通过SOEC将多余的电量存贮到燃料中,并在低谷时通过SOFC补充电量。氢气具有高能量密度、清洁和环境友好等特点,是一种合适的能量载体。单体SOEC由空气电极、电解质和燃料电极组成。在SOEC电解制氢的过程中,空气电极缓慢的氧析出动力学速率严重影响了氢气的制备效率,并且空气电极的劣化也导致了SOEC在长期运行中的衰减,因此,空气电极的研发对SOEC的应用至关重要。从氧离子导体型电解质SOEC(O-SOEC)和质子导体型SOEC (H-SOEC)两方面对SOEC电解制氢中的空气电极研究现状进行了综述,系统整理了O-SOEC和H-SOEC的空气电极材料,对比了不同材料的电化学性能及稳定性,归纳了提升空气电极性能及稳定性的有效策略,并对SOEC空气电极的发展进行了展望。

Solid oxide electrolysis cell(SOEC) is an energy conversion device that can directly convert electric energy into chemical energy stored in fuel gas, with high energy conversion efficiency. The combination of SOEC and solid oxide fuel cell(SOFC) can solve the problem of intermittent power generation from emerging clean energy such as wind energy and solar energy. When the power generation reaches peak, the excess power could be stored in fuels with SOEC, while the power is supplemented with SOFC at the ravine. Hydrogen is a suitable energy carrier because of its high energy density, cleanness and environmental friendliness. Single SOEC is composed of an air electrode, an electrolyte and a fuel electrode. In the process of hydrogen production through SOEC electrolysis, the slow oxygen precipitation kinetic rate of air electrode seriously affects the production rate of hydrogen, while the degradation of the air electrode also leads to the attenuation of SOEC after long-term operation. Therefore, the performance of the air electrode is very important for the application of SOEC. The research progress of air electrode in SOEC steam electrolysis is reviewed from two aspects: oxygen ion conductor electrolyte SOEC(O-SOEC) and proton conductor SOEC(H-SOEC). The air electrode materials of O-SOEC and H-SOEC are systematically sorted out, the electrochemical properties and stability of different materials are compared, the effective strategies to improve the performance and stability of the air electrode are summarized, and the development of SOEC air electrode is prospected.