Direct ammonia low-temperature symmetrical solid oxide fuel cells with composite semiconductor electrolyte

Abstract

In this work, a low-temperature symmetrical solid oxide fuel cell with Ni-NCAL|SDC/NCAL|Ni-NCAL (70 SDC:30 NCAL) configuration was successfully constructed by a simple dry press method. At 500 and 550 °C, the peak power densities of the cell in ammonia were 501 and 755 mW cm−2, and in hydrogen were 670 and 895 mW cm−2, respectively. EIS data showed that the Rp values of the cell in ammonia and hydrogen at 550 °C were 0.250 and 0.246 Ω cm−2, respectively, indicating the excellent catalytic activity of the Ni-NCAL electrode toward ammonia decomposition and hydrogen oxidation. The different cell output can be ascribed to additional ammonia decomposition steps compared to hydrogen. The noticeable reaction product on the surface of the Ni foam was detrimental to ammonia decomposition. In summary, a symmetrical cell with SDC/NCAL semiconductor electrolyte and Ni-NCAL electrodes exhibited higher electrochemical performance at low temperature than the results reported to date. Therefore, higher electrochemical performance can be expected from this cell configuration with more efficient ammonia decomposition catalysts.

Keywords

• Low-temperature solid oxide fuel cell
• Hydrogen
• Ammonia
• SDC/NCAL
• Ni-NCAL electrodes