Ni-Substituted Sr(Ti,Fe)O3 SOFC Anodes: Achieving High Performance via Metal Alloy Nanoparticle Exsolution

Abstract

Ni-Fe nanoparticles are observed to exsolve from Ni-substituted Sr 0.95 (Ti 0.3 Fe 0.63 Ni 0.07 )O 3Àd anode. The exsolved nanoparticles act to enhance hydrogen dissociative adsorption, yielding much lower anode polarization resistance and higher cell performance, especially under low pH 2 and temperatures, which is comparable with the current Ni-based cermets.

In Situ Investigation of Reversible Exsolution/Dissolution of CoFe Alloy Nanoparticles in a Co‐Doped Sr2Fe1.5Mo0.5O6−δ Cathode for CO2 Electrolysis

“…The interplanar spacing of the substrate is 0.284 nm, corresponding to the (105) plane of the layered perovskite, while the lattice space of the nanoparticle is 0.203 nm, which is quite close to that of (110) plane of CoFe alloy phase. Meanwhile, the profile view of the interface reveals that part of the oblate spheroids are submerged into the substrate, indicative of a strong interaction between the perovskite substrate and the anchored nanoparticles 2b,6c,9,10b,12,16. This anchoring effect is expected to provide enhanced thermal stability through preventing the severe agglomeration during long‐term operation .…”

The enhanced electrochemical response of Sr(Ti0.3Fe0.7Ru0.07)O3−δ anodes due to exsolved Ru–Fe nanoparticles

“…4,5 The latter material yields polarization resistance as low as 0.13cm 2 at 800 o C in humidified hydrogen, approaching the values achieved in state-of-the-art Ni-YSZ anodes. 6 Oxide anode performance can be further improved by a catalytic metal present either in the anode formulation (e.g., Ni-YSZ), introduced via infiltration, [7][8][9][10] or substituted into the oxide and subsequently exsolved to form catalytic nanoparticles on the oxide surfaces. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] The exsolution anodes have the advantages of utilizing a relatively small amount of active catalyst, which is present as highly active nanoparticles within a well-defined layer, and that no additional processing steps are required.…”

Progress and Opportunities for Exsolution in Electrochemistry

“…Indeed, exsolution anodes gave a significantly worse performance compared to the standard NiO/YSZ cermet and were thus not considered as an industrially viable replacement. Recently, Barnett has shown that exsolution electrodes on the basis of A-site-deficient and B-site-doped strontium titanates have comparable current densities to NiO/YSZ, and are therefore becoming industrially relevant materials [33]. These results show great promise that cleverly engineered stoichiometry can be synthesized in order to form mixed ionic-electric conductors (MIECs), tailor the electronic properties of the exsolved catalytic nanoparticles through alloying, [33,[35][36][37][38][39] and utilize strain engineering or twinning to enhance catalytic properties [40].…”

“…shows that Sr 0.95 Ti 0.3 Fe 0.63 Ni 0.07 O 3−δ (STFN)-based anodes under a flow of humid hydrogen could generate over 4 A/cm 2 , making them highly competitive with (if not exceeding) the performance of NiO cermets[33,34].…”