利用钐掺杂氧化铈提高燃料电池阳极活性

用浸渍法制备并采用交流阻抗、极化等技术考察了不同组成的Ni-Sm3＋掺杂的CeO2(SDC) 复合镍阳极的电化学性能及相应电池的功率输出性能.结果表明，SDC掺入镍阳极后,阳极极化过电位及电池的欧姆电阻显著减小.其中阳极过电位的减小与SDC掺入镍电极引起的三相界扩展有关，但SDC的掺入同时引起了电极反应活化能的增加,造成低温下Ni-SDC的极化过电位大于纯Ni电极.高温下,Ni-SDC阳极的阻抗谱由两个半圆组成，其中高频半圆随着SDC掺入量的增加而减小,而低频环与SDC的掺入量基本无关.低温下只观察到一个高频环.高频环可能对应三相界反应,而低频环可能对应氢的解离吸附及扩散.75％（w）Ni-25％（w）SDC/La0.9Sr0.1Ga0.8Mg0.2O3(LSGM)/Sm0.5Sr0.5CoO3(SSC)在所研究的电池中具有最大功率输出密度，其值在1073、973、873 K下分别达到1.1、0.43、0.14 W•cm－2.

Improvement of the Performance of Fuel Cells Anodes with Sm3+ Doped CeO2

Various Ni-15％ Sm3＋(x) doped CeO2(Ni-SDC)composite anodes prepared by impregnation method were studied to unveil the role of SDC in improving the performance of Ni anode. The electrochemical properties and the power generation characteristics of the cells based on these anodes show that the performance of the cells were improved significantly by the addition of SDC into Ni due to the reduced ohmic resistance and anodic overpotential. The decrease of anodic overpotential after the introduction of SDC could be due to the extension of three-phase-boundary (TPB) and the increase of active sites for H2 oxidation. However, the introduction of SDC also leaded to an increase of activation energy, which resulted in a higher anodic overpotential for Ni-SDC anodes at low temperatures compared with pure Ni. The impedance spectra of Ni-SDC anode consisted of two arcs at high temperatures. The high frequency arc increased with the amount of SDC, while the low frequency arc showed no dependency on the amount of SDC. The high frequency arc could be related to the charge transfer reaction at TPB, and the low frequency arc could correspond to the disassociative adsorption of H2 and the following diffusion processes. 75％(w) Ni-25％(w) SDC/LSGM/SSC exhibited the highest power density among the cells studied, and the highest power density at 1073, 973, 873 K reached 1.1, 0.43, 0.14 W•cm－2, respectively. The cells also showed good stability.