基于阳离子导体的可再生钙钛矿型固体氧化物燃料电池阳极材料的研究

Solid oxide fuel cell (SOFC) is considered to be the most promising power generation system because of its all-solid structure, excellent fuel flexibility and no requirement for precious metal catalysts. SOFC fueled by fossil fuels has broad application prospects; however, their widespread use is hindered by the poor sulfur tolerance of conventional nickel cermet anode, leading to substantially low lifetime for commercialization. Therefore, the key solution is to design and develop anode materials with high activity for electrochemical oxidation reactions, sulfur tolerance and operational stability. We have reported a series of perovskite oxide anode materials with sulfur tolerance, which unfortunately exhibit low electrochemical oxidation activity and poor stability in H2S-containing H2 atmospheres with high H2S concentration (>1000 ppm). This project aims to develop a series of new SOFC anode materials with high activity, stability, sulfur tolerance and regeneration capability. This project starts with a rational screening of metal cations that can dope into and exsolve from the perovskite structure (referred to as regeneration), followed by the experimental doping of these cations into perovskite oxides with cationic conductivity. By controlling the type, amount and site of these regenerable dopants, high electrochemical activity, excellent operation stability and superior sulfur tolerance can be achieved at the same time. In this project, the mechanisms of fuel electrochemical oxidation, anti-sulfur poisoning and regeneration on the newly-developed anodes will also be investigated in depth. The successful implementation of this project will provide theoretical and experimental basis for the design and development of SOFC anode materials.

固体氧化物燃料电池（SOFC）以其全固态结构、燃料多样性、无需贵金属催化剂等突出优点被认为是最有前景的发电系统。基于化石燃料的SOFC具有广泛的应用前景，其核心问题是设计开发具有高电化学活性、抗硫中毒能力和稳定性的阳极材料。我们已成功研发出一系列具有抗硫中毒能力的钙钛矿氧化物阳极材料，但是这些材料的电化学活性较差，并在含有高H2S浓度（>1000 ppm）的H2气氛中容易失活。本项目将设计开发一系列新型的高活性的、稳定的、具有可再生和抗硫中毒能力的SOFC阳极材料。本项目拟引入可在钙钛矿氧化物晶格内溶入析出（可再生）的金属离子到钙钛矿型阳离子导体中，并对掺杂元素的种类、含量和位置进行有效调控，进而实现优异电化学活性、稳定性和抗硫中毒能力的共赢。本项目将对这种新型阳极的燃料电化学氧化机制及其抗硫中毒、可再生机理进行深度研究。本项目的成功实施将为SOFC阳极材料的设计开发提供理论和实验依据。

设计开发具有高电化学活性、抗硫中毒能力和稳定性的阳极材料是固体氧化物燃料电池（SOFC）直接使用沼气、天然气等非H2燃料的关键。但是，目前SOFC最常用的Ni基陶瓷阳极存在高温还原气氛下氧化还原稳定性差、易硫中毒、烧结严重以及低温（电）催化活性低等缺点。为了有效解决Ni基陶瓷阳极存在的问题，在本项目中，我们成功开发了一系列新型的、高活性的、稳定的、具有可再生和抗硫中毒能力的SOFC阳极材料如La0.6Sr0.4Ni0.2Mn0.2Fe0.6O3-δ、La0.6Sr0.4Co0.2Mn0.2Fe0.6O3-δ、La0.52Sr0.28Ti0.94Ni0.03Co0.03O3-δ、La0.52Sr0.28Ti0.94Ni0.06O3-δ、La0.52Sr0.28Ti0.94Co0.06O3-δ、Pr0.6Sr0.4Co0.2Fe0.75Ru0.05O3-δ、Pr0.6Sr0.4Co0.2Fe0.8O3-δ、Ba(Zr0.1Ce0.7Y0.1Yb0.1)0.95Ni0.05O3-δ。在本项目中，我们引入可在钙钛矿氧化物晶格内溶入析出的金属离子到钙钛矿型阳离子导体中，并对掺杂元素的种类、含量和位置进行有效调控，进而实现优异电化学活性、稳定性和抗硫中毒能力的共赢。采用纳米颗粒析出的钙钛矿材料作为阳极的SOFC单电池取得了1.03 W cm-2的峰值功率密度；氧化还原循环次数达到60次。此外，我们通过进行一系列表征、调控可再生金属阳离子的类型和合理选择钙钛矿型主体材料深度研究了纳米颗粒析出对钙钛矿阳极的燃料电化学氧化活性、抗硫中毒和耐烧结能力的提升机制。综上所述，本项目的研究可为SOFC阳极领域开辟一个崭新的研究方向，提高我国在该领域的国际竞争力和影响力。本项目的研究也可为用于其它领域如透氧膜、氧传感器、透氢膜、低温氧催化剂的钙钛矿材料的设计与研制提供借鉴。