Interactions of nickel/zirconia solid oxide fuel cell anodes with coal gas containing arsenic
Interactions of nickel/zirconia solid oxide fuel cell anodes with coal gas containing arsenic
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镍/氧化锆固体氧化物燃料电池阳极与含砷煤气的相互作用
DOI：
10.1016/j.jpowsour.2009.04.042
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发表时间：
2009
影响因子：
9.2
通讯作者：
L. Pederson
中科院分区：
文献类型：
--
作者：
C. Coyle;O. Marina;E. Thomsen;D. Edwards;Carolyn N. Cramer;G. Coffey;L. Pederson
在700-800°C、含砷0- 10 ppm的合成煤气中研究了阳极支撑和电解质支撑固体氧化物燃料电池的性能。砷被发现强烈的相互作用与镍，导致在形成的镍-砷固溶体，Ni 5As 2和Ni 11 As 8，取决于温度，砷浓度，和反应时间。对于阳极支撑的电池，阳极支撑中的电连接性的损失是降解的主要模式，因为镍被转化为迁移到表面以形成大颗粒的砷化镍相。电池故障发生之前，整个阳极被转化为砷化镍，并遵循砷分压依赖性的倒数平方根，这是一致的扩散为基础的限速步骤。电解质支持的电池故障发生得更快，其具有显著更小的镍库存。对于这些电池，失效时间随砷浓度的倒数线性变化。当砷到达阳极/电解质界面时发生故障，尽管镍反应产物的附聚也可能有贡献。用镍/氧化锆试样进行的试验表明，砷基本上完全捕获在燃料气体入口附近的窄带中。砷的浓度为10 ppb或更低，估计会导致可接受的燃料电池退化率。
The performance of anode-supported and electrolyte-supported solid oxide fuel cells was investigated in synthetic coal gas containing 0–10ppm arsenic at 700–800°C. Arsenic was found to interact strongly with nickel, resulting in the formation of nickel–arsenic solid solution, Ni5As2and Ni11As8, depending on temperature, arsenic concentration, and reaction time. For anode-supported cells, loss of electrical connectivity in the anode support was the principal mode of degradation, as nickel was converted to nickel arsenide phases that migrated to the surface to form large grains. Cell failure occurred well before the entire anode was converted to nickel arsenide, and followed a reciprocal square root of arsenic partial pressure dependence that is consistent with a diffusion-based rate-limiting step. Failure occurred more quickly with electrolyte-supported cells, which have a substantially smaller nickel inventory. For these cells, time to failure varied linearly with the reciprocal arsenic concentration. Failure occurred when arsenic reached the anode/electrolyte interface, though agglomeration of nickel reaction products may have also contributed. Test performed with nickel/zirconia coupons showed that arsenic was essentially completely captured in a narrow band near the fuel gas inlet. Arsenic concentrations of ∼10ppb or less are estimated to result in acceptable rates of fuel cell degradation.