Development of improved anodes in solid oxide fuel cells for conversion of synthesis gas from thermo-chemical gasification of biomass

氧化物陶瓷燃料电池（SOFC）提供了将合成气从热化学生物质气化转化为电能的可能性，在小型分散系统中效率非常高。这已经在几个使用传统SOFC燃料电池的中试工厂中得到证明。主要的困难是生物合成气中所含的杂质，如含硫和氯的成分，甚至是更高级的碳氢化合物（焦油）。在第一个项目阶段，SynSOFC I开发了新的SOFC阳极，并获得了关于不同污染物对标准电池和新电池影响的重要发现。几ppm的含硫分子的含量已经引起了高的、部分可逆的性能退化。但不同的焦油物质对细胞的影响不同。虽然甲苯对电池的影响很小，但萘的加入导致了强烈的、大部分可逆的性能下降。相比之下，在苯酚的影响下，观察到阳极基板结构的结构退化，而电池性能没有明显降低。由于在SynSOFC I期间，阳极基板的材料已被证明部分易受降解过程的影响，因此将在SynSOFC II的背景下连同阳极本身一起研究和优化阳极支撑件的稳定性。因此，计划在电解质支持的电池中使用已经开发的Ni/GDC阳极。此外，全陶瓷阳极也将在电解质支持的电池中进行研究。将详细阐述对Ni（O）和8 YSZ（掺杂有8摩尔%钇的氧化锆）标准阳极的调查，以澄清造成性能损失和退化的微观机制。为了优化知识的获取，除了电化学表征之外，还将研究新的和标准阳极材料的化学耐受性。在SynSOFC I期间安装的用于SOFC堆与非热流化床气化器耦合的测试台用于在系统环境中验证新开发的10 x10 cm ²全电池阳极结构。

Oxide ceramic fuel cells (SOFC) offer the possibility of converting synthesis gas from thermochemical biomass gasification into electricity with very high efficiency in small decentralised systems. This has already been proven in several pilot plants with conventional SOFC fuel cells. The main difficulties are the impurities contained in biosyngas, such as components containing sulphur and chlorine or even higher hydrocarbons (tars). In the first project phase SynSOFC I new SOFC anodes have been developed and important findings regarding the effect of different contaminants on standard cells and new cells could be obtained. Contents of few ppm of sulfur-containing molecules already caused a high, partially reversible performance degradation. However, different tar substances had different effects on the cells. While toluene showed little effect on the cells, naphthalene addition resulted in strong, mostly reversible performance declines. In contrast, structural degradation of anode substrate structures without a noticeable decrease in cell performance was observed under the influence of phenol. Since during SynSOFC I the material of the anode substrate has been proven to be partially susceptible to degradation processes, the stability of the anode support is to be investigated and optimized in the context of SynSOFC II together with the anode itself. It is therefore planned to use the already developed Ni/GDC anodes in electrolyte-supported cells. In addition, full-ceramic anodes will be investigated in electrolyte-supported cells as well. The investigations on standard anodes of Ni(O) and 8 YSZ (zirconium oxide doped with 8 mol% yttrium) will be elaborated to clarify the microscopic mechanisms responsible for performance losses and degradation. In order to optimize the gain of knowledge, the chemical tolerance of the new and standard anode materials is to be investigated in addition to electrochemical characterization. The test stand installed during SynSOFC I for the coupling of SOFC stacks with an allothermal fluidized bed gasifier serves to validate the newly developed anode structures on 10x10cm² full cells in a system environment.