Effects of Cobalt Addition on the Catalytic Activity of the Ni-YSZ Anode Functional Layer and the Electrochemical Performance of Solid Oxide Fuel Cells

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• 作者：Ting Guo ; Xiaolei Dong ; Mandar M. Shirolkar ; Xiao Song ; Meng Wang ; Lei Zhang ; Ming Li ; Haiqian Wang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：September 24, 2014
• 年：2014
• 卷：6
• 期：18
• 页码：16131-16139
• 全文大小：576K
• ISSN：1944-8252

文摘

The effects of cobalt (Co) addition in the Ni-YSZ anode functional layer (AFL) on the structure and electrochemical performance of solid oxide fuel cells (SOFCs) are investigated. X-ray diffraction (XRD) analyses confirmed that the active metallic phase is a Ni_1鈥?i>xCo_x alloy under the operation conditions of the SOFC. Scanning electron microscopy (SEM) observations indicate that the grain size of Ni_1鈥?i>xCo_x increases with increasing Co content. Thermogravimetric analyses on the reduction of the Ni_1鈥?i>xCo_xO-YSZ powders show that there are two processes: the chemical-reaction-controlled process and the diffusion-controlled process. It is found that the reduction peak corresponding to the chemical-reaction-controlled process in the DTG curves moves toward lower temperatures with increasing Co content, suggesting that the catalytic activity of Ni_1鈥?i>xCo_x is enhanced by the doping of Co. It is observed that the SOFC shows the best performance at x = 0.03, and the corresponding maximum power densities are 445, 651, and 815 mW cm^鈥? at 700, 750, and 800 掳C, respectively. The dependence of the SOFC performance on the Co content can be attributed to the competing results between the decreased three-phase-boundary length in the AFL and the enhanced catalytic activity of the Ni_1鈥?i>xCo_x phase with increasing Co content.

Keywords:

nickel鈭抍obalt alloy; catalytic; solid oxide fuel cells; anode functional layer; three-phase boundary; thermogravimetric analyses