Surface Regulating of a Double‐Perovskite Electrode for Protonic Ceramic Fuel Cells to Enhance Oxygen Reduction Activity and Contaminants Poisoning Tolerance

Abstract

Protonic ceramic fuel cells (PCFCs) are one of the most efficient energy conversion devices. However, the performance of current PCFCs is greatly limited by the sluggish oxygen reduction reaction (ORR) kinetics and the fast degradation of the cathode due to contaminants poisoning (such as Cr species and steam). Here, a surface regulation of a double perovskite PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) cathode by a Pr0.9Fe0.7Co0.3O3 (PFC) catalyst coating to enhance the ORR activity and stability is reported. When tested in direct contact with Cr in the air with 3% H2O at 650 °C, the polarization resistance (Rp) of the PFC coated PBSCF (PFC‐PBSCF) electrode increases from ≈0.39 to 0.45 Ω cm2 after 100 h operation; in contrast, the Rp of a PBSCF electrode increases from 0.63 to 0.82 Ω cm2. Further, a PCFC with the PFC‐PBSCF cathode demonstrates an excellent peak power density (≈1.08 W cm–2 at 650 °C) and significantly enhanced durability (degradation rate of 0.03% h−1), much better than those of the cells with a PBSCF cathode (≈0.75 W cm–2 and degradation rate of 0.12% h−1). Raman spectroscopy and density functional theory calculations indicate that the PFC catalyst coating diminishes the formation of Cr species, such as (Ba1‐xSrx)CrO4, on the cathode surface.

Surface Self‐Assembly Protonation Triggering Triple‐Conductive Heterostructure with Highly Enhanced Oxygen Reduction for Protonic Ceramic Fuel Cells

“…Herein, the much improved electrochemical performance is owing to the proton-conducting BZO-based NPs; simultaneously, partial acceptor doping of cobalt can also significantly accelerate the p-ORR process. As summarized in Figure5c, the PPDs of BZO@PBC (PBCZ08) nanocomposite cathode in this work surpasses most of the electrochemical performances reported for protonic ceramic fuel cells under similar operating conditions[17,18,34,[48][49][50][51][52][53][54] sufficiently proving the rationality of this schematic design. Figure5dshows the R p values of 0.04 and 0.13 Ω cm 2 for single cells with PBCZ08 and PBC cathodes measured at 700 °C, respectively.…”

“…c) PPDs of the BZO@PBC nanocomposite cathode and various cathodes in the reported research.d,e) EIS curves and f) Comparison of R p values with the reported works. g) Durable stability test of the single cells with PBC and PBCZ08 cathodes at 600 °C under an applied voltage of 0.7 V. PrBaCo 2 O 5+δ (PBC),[52] PrBa 0.9 Ca 0.1 Co 1.85 Zn 0.15 O 5+δ (PBCCZ),[51] PrBaCo 1.75 Ta 0.25 O 5+δ (PBCT),[34] PrBaCo 1.6 Fe 0.2 Nb 0.2 O 5+δ (PBCFN),[53] PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF),[54] La 0.6 Ba 0.4 CoO 3−δ (LBC),[50] La 0.6 Sr 0.4 CoO 3−δ (LSC),[50] La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ (LSCF),[50] Sm 0.5 Sr 0.5 CoO 3−δ (SSC),[49] BaCo 0.7 (Ce 0.8 Y 0.2 ) 0.3 O 3−δ (BCCY),[17] BaCe 0.4 Fe 0.4 Co 0.2 O 3−δ (BCFC),[48] PrNi 0.5 Mn 0.5 O 3 + PrO x (PNM-PrO x ),[18] PrBaCo 1.92 Zr 0.08 O 5+δ (PBCZ08).…”

Building Efficient and Durable Hetero‐Interfaces on a Perovskite‐Based Electrode for Electrochemical CO2 Reduction

“…Surface modification methods using liquid solution infiltration have been heavily applied to tune the interface properties of nano-catalysts and skeleton. [36,[44][45][46][47] As a result, the overall electrochemical performance has been significantly improved by the synergetic coupling of the different phases. [48] Although the performance improvements of surface modification are encouraging, the aggregation of the infiltrated nanoparticles is still a major concern for the long-term operations.…”

Visiting the roles of Sr‐ or Ca‐ doping on the oxygen reduction reaction activity and stability of a perovskite cathode for proton conducting solid oxide fuel cells

“…Proton‐conducting solid oxide fuel cells (H‐SOFCs) are gaining more and more attention due to their increased protonic conductivity and benefits at low temperatures 1–6 . Additionally, water is produced on the cathode side, preventing the oxidation of Ni in the fuel electrode and the dilution of the fuel gas 7 .…”