Self‐Construction of Efficient Interfaces Ensures High‐Performance Direct Ammonia Protonic Ceramic Fuel Cells

Abstract

Direct ammonia protonic ceramic fuel cells (PCFCs) are highly efficient energy conversion devices since ammonia as a carbon‐neutral hydrogen‐rich carrier shows great potential for storage and long‐distance transportation when compared with hydrogen fuel. However, traditional Ni‐based anodes readily suffer from severe structural destruction and dramatic deactivation after long‐time exposure to ammonia. Here a Sr2Fe1.35Mo0.45Cu0.2O6−δ (SFMC) anode catalytic layer (ACL) painted onto a Ni‐BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) anode with enhanced catalytic activity and durability toward the direct utilization of ammonia is reported. A tubular Ni‐BZCYYb anode‐supported cells with the SFMC ACL show excellent peak power densities of 1.77 W cm−2 in wet H2 (3% H2O) and 1.02 W cm−2 in NH3 at 650 °C. A relatively stable operation of the cells is obtained at 650 °C for 200 h in ammonia fuel. Such achieved improvements in the activity and durability are attributed to the self‐constructed interfaces with the phases of NiCu or/and NiFe for efficient NH3 decomposition, resulting in a strong NH3 adsorption strength of the SFMC, as confirmed by NH3 thermal conversion and NH3‐temperature programmed desorption. This research offers a valuable strategy of applying an internal catalytic layer for highly active and durable ammonia PCFCs.

Utilization of Thermocatalysts in Solid Oxide Fuel Cells (SOFCs) Fed with Hydrogen-Rich Fuels: A Mini-Review

“…Ni et al performed a thermodynamic analysis of an NH 3 -fueled SOFC/PCFC and pointed out that the NH 3 -fueled PCFC was superior to the NH 3 -fueled SOFC in terms of theoretical maximum efficiency . Numerous studies have focused on NH 3 -fueled PCFCs. − Pan et al painted an iron catalyst onto the surface of a tubular Ni-BZCYYb anode, as shown in Figure . The PCFC with an iron catalyst layer (denoted as Fe-cell) had a PPD of 685 mW cm –2 at 650 °C in NH 3 , higher than 506 mW cm –2 of the bare cell.…”

In situ formed catalysts for active, durable, and thermally stable ammonia protonic ceramic fuel cells at 550 °C

“…17 A PCFC with a catalytic layer of Sr 2 Fe 1.35 Mo 0.45 Cu 0.2 O 6− δ (SFMC) on the outer surface of the anode has demonstrated a relatively stable operation at >650 °C; the exsolved Fe and Cu nanoparticles from the SFMC reacted with Ni to create highly active phases of NiCuFe and/or NiFe on the anode surface, resulting in improved performance and stability. 18 However, the relatively poor ammonia decomposition activity and durability at low temperatures (such as 550 °C) remain significant challenges.…”