Building Ruddlesden–Popper and Single Perovskite Nanocomposites: A New Strategy to Develop High‐Performance Cathode for Protonic Ceramic Fuel Cells

Abstract

Here a new strategy is unveiled to develop superior cathodes for protonic ceramic fuel cells (PCFCs) by the formation of Ruddlesden–Popper (RP)‐single perovskite (SP) nanocomposites. Materials with the nominal compositions of LaSrxCo1.5Fe1.5O10−δ (LSCFx, x = 2.0, 2.5, 2.6, 2.7, 2.8, and 3.0) are designed specifically. RP‐SP nanocomposites (x = 2.5, 2.6, 2.7, and 2.8), SP oxide (x = 2.0), and RP oxide (x = 3.0) are obtained through a facile one‐pot synthesis. A synergy is created between RP and SP in the nanocomposites, resulting in more favorable oxygen reduction activity compared to pure RP and SP oxides. More importantly, such synergy effectively enhances the proton conductivity of nanocomposites, consequently significantly improving the cathodic performance of PCFCs. Specifically, the area‐specific resistance of LSCF2.7 is only 40% of LSCF2.0 on BaZr0.1Ce0.7Y0.2O3−δ (BZCY172) electrolyte at 600 °C. Additionally, such synergy brings about a reduced thermal expansion coefficient of the nanocomposite, making it better compatible with BZCY172 electrolyte. Therefore, an anode‐supported PCFC with LSCF2.7 cathode and BZCY172 electrolyte brings an attractive peak power output of 391 mW cm−2 and excellent durability at 600 °C.

Thickness‐dependent high‐performance solid oxide fuel cells with Ba0.5Sr0.5Co0.8Fe0.2O3‐δ cathode

“…The peak at intermediate frequency is corresponding to the surface oxygen diffusion and dissociation processes. 44 With the increase of electrode thickness, the change of peaks at high frequency is weak, while the peaks at intermediate frequency obviously change, indicating that changing the electrode can effectively optimize the oxygen surface diffusion and dissociation processes.…”

“…These symmetrical cells were all prepared by performing calcination once at 1000°C for 2 h. Though these impedance spectra show a similar shape, it is evident that changing the thickness can effectively affect the electrode polarization resistance. No arc at low frequencies was observed in all impedance spectra of the BSCF electrodes with various thicknesses, indicating that the polarization resistance comes from charge transfer process, and oxygen surface diffusion and dissociation process 44 . The impedance spectra measured at 600°C are then fitted using an equivalent circuit of R ohm (R 1 Q 1 ) (R 2 Q 2 ) to distinguish two processes.…”

“…No arc at low frequencies was observed in all impedance spectra of the BSCF electrodes with various thicknesses, indicating that the polarization resistance comes from charge transfer process, and oxygen surface diffusion and dissociation process. 44 The impedance spectra measured at 600 C are then fitted using an equivalent circuit of R ohm (R 1 Q 1 ) (R 2 Q 2 ) to distinguish two processes. The R ohm denotes the ohmic resistance.…”

Advanced Materials for Thin‐Film Solid Oxide Fuel Cells: Recent Progress and Challenges in Boosting the Device Performance at Low Temperatures

“…This composition outperformed the single phase in both performance and durability. [188] The concept of a triple-ion (O 2− /e − /H + ) conducting cathode for PCFC was pursued by Kim et al in 2014. They developed a novel double-layered perovskite material, NdBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (NBSCF), purported to facilitate the ions migration through channels between the AO layers of the AA′B 2 O 5 structure, leading to an outstanding PCFC power density, 0.69 W cm −2 at 600 °C.…”

An electrochemical assessment of pristine SrCoO3‐δ using the distribution of relaxation times analysis

“…12 However, when coupled with the other phases, interesting and outstanding electrochemical properties could be obtained, which make the research of the electrochemical properties of pristine SCO an interesting issue. [13][14][15] Electrochemical impedance spectroscopy (EIS) is a powerful tool in investigating the electrical properties of the electro-ceramic materials in SOFCs. 16 Precise description of electrochemical impedance enables definite description of the interfacial mass exchange or ion transform in the lattice.…”