Infiltrated NiCo Alloy Nanoparticle Decorated Perovskite Oxide: A Highly Active, Stable, and Antisintering Anode for Direct-Ammonia Solid Oxide Fuel Cells.

Abstract

Direct ammonia solid oxide fuel cell (DA-SOFC) is superior to low-temperature direct ammonia fuel cell using anion exchange membrane because of much improved anode reaction kinetics at elevated temperature. However, significant performance degradation due to severe sintering of conventional nickel cermet anode under operating conditions is a big challenge for realizing its practical use. Herein, a high-performance anode based on La0.55 Sr0.30 TiO3- δ (LST) perovskite substrate with its surface decorated with in situ exsolved and strongly coupled NiCo alloy nanoparticles (NPs) is designed and fabricated for DA-SOFCs, exhibiting superior catalytic activity for NH3 decomposition reaction due to balanced NH3 adsorption and N2 desorption processes. An electrolyte-supported single cell with infiltrated NiCo/LST on Sm0.2 Ce0.8 O1.9 scaffold anode delivers a maximum power density of 361 mW cm-2 at 800 °C in NH3 fuel, superior to similar SOFCs with Ni or Co NP-decorated LST based anodes (161 and 98 mW cm-2 ). Furthermore, the SOFC with this newly developed anode displays favorable operational stability without obvious performance degradation at 700 °C for a test period of ≈120 h, attributed to its high antisintering capability. This study provides some strategies to develop highly active, stable, and antisintering perovskite-based nanocomposite for DA-SOFCs, facilitating the practical use of this technology.