摘要：
The over-exploitation and over-utilization of fossil fuel resources such as petroleum and coal has aggravated energy and environment problem in the 2 1 st century,and urged the development of highly-efficient and cost-effective energy conversion and storage devices to become the research topic of this new era.Among many candidates of energy conversion and storage devices, metal-air batteries and intermediate-low temperature solid oxide fuel cells can efficiently convert chemical energy into electric energy, and enjoy the advantages of low cost,high efficiency and environmental friendliness.Hence,they have provoked intensive and fruitful research endeavors with amazing achievements over the past decade.However,the sluggish kinetics of the oxygen reduction and evo-lution reactions greatly reduces the energy conversion efficiency,and consequently increases the application cost and severely hinders the commercialization of these two devices.Cobalt-based electrocatalysts,as highly efficient cathode materials with lower cost than noble metals,feature mixed ionic and electronic conductivity which can effectively reduce polarization and contribute to high catalytic activity for oxygen reduction and evolution reactions,and thereby have been holding growing interest recently. For metal-air batteries,cobalt-based electrocatalysts such as simple oxides,spinel oxides,perovskite oxides,and others can sig-nificantly improve the discharge capacity and cycle life,and simultaneously,lower the charge voltage and polarization.On the other hand,the catalytic activity and stability need to be further enhanced,and the catalytic mechanisms and active sites deserve further rational exploration and ascertainment.Similarly,cobalt-based electrocatalysts including La1-xSrxCoO3-δ,La1-xSrxCo1-yFeyO3-δ, Ba1-xSrxCoyFe1-yO3-δand cobalt-based double perovskites show evident efficacy in reducing the cathode polarization resistance and area specific resistance as well as increasing the power density,while nonetheless sustaining a generally higher thermal expansion coefficient and a rather poor stability compared to some other competitors. To further improve the catalytic performance of cobalt-based electrocatalysts for metal-air batteries and intermediate-low tempe-rature solid oxide fuel cells,researchers have developed many useful and productive methods,exemplified by metal elements doping, composite cathode materials preparation,and noble metals decoration. This review provides a brief introduction of the structure and working principle of metal-air batteries and intermediate-low tem-perature solid oxide fuel cells,and a vivid description upon the latest attempts and achievements for the fabrication,modification and performance of the rich variety of cobalt-based electrocatalysts,mainly including simple oxides,perovskites oxides,spinel oxides and double perovskites.%在21世纪的今天,由石油、煤炭等化石资源的过度开发与使用所引发的能源和环境问题日趋严重,开发经济、高效的能源转换与存储装置已成为新时代的研究主题.金属-空气电池和中低温固体氧化物燃料电池,作为高效的能源转换与存储装置,可以实现化学能向电能的高效转换,具有效率高、环境友好、成本低的显著优点,在过去十几年内受到了研究者的广泛关注,取得了惊人的成果.但与此同时,人们在研究中发现阴极(正极)缓慢的氧还原和氧析出反应速率极大地降低了电池转换效率,增加了应用成本,在很大程度上制约了金属-空气电池和中低温固体氧化物燃料电池的商业化发展和应用.钴基催化剂作为一种高效阴极材料,相比贵金属成本较低,且具有混合离子-电子导电性,可以有效降低极化电阻,对阴极氧还原和氧析出反应显示出高催化活性,近年来吸引了国内外学者极大的研究兴趣.对于金属-空气电池,虽然钴基催化剂如钴氧化物、尖晶石型氧化物、钙钛矿型氧化物等材料能够显著地提高金属-空气电池的电容量和循环性能,并且降低充电电压,有效降低极化,但是其催化活性和稳定性有待提高,催化机理和活性位点也需要进一步明确和探究;对于中低温固体氧化物燃料电池,钴基催化剂包括 La1-xSrxCoO3-δ、La1-xSrxCo1-yFeyO3-δ、Ba1-xSrxCoyFe1-yO3-δ和钴基双钙钛矿等材料可以大大降低阴极极化电阻和面积比电阻,提高功率密度,但是相对其他催化剂,热膨胀系数普遍较高,稳定性也较差.为了进一步提高钴基催化剂应用在金属-空气电池和中低温固体氧化物燃料电池中的催化活性,研究者采用了掺杂其他金属元素、与其他物质组成复合阴极材料以及贵金属修饰等方法,在很大程度上提高了这两种电池的性能.本文简要介绍了金属-空气电池和中低温固体氧化物燃料电池的结构、工作原理,并在此基础上着重评述了近年来面向这两种能源转换与存储器件的,包括钴氧化物、钙钛矿型氧化物、尖晶石型氧化物和双钙钛矿氧化物等在内的各种钴基电催化剂的制取、改性和性能研究探索与成果.
