Superionic Conducting Bismuth Oxide-Based Electrolytes for Solid Oxide Fuel Cells

2025-07-25T03:25:27Z

Title: Superionic Conducting Bismuth Oxide-Based Electrolytes for Solid Oxide Fuel Cells Author(s): Lee, Kang-Taek Abstract: The erbia-stabilized Bi2O3 (ESB) is known as a promising SOFC electrolyte material due to its excellent ionic conductivity compared to conventional oxide ion conductors such as doped CeO2 and stabilized ZrO2. Despite its superior ionic conductivity at reduced operating temperatures below 700 oC, ESB has not been a practical choice for an electrolyte material for SOFCs because its thermodynamic instability under reducing atmosphere and kinetic instability of time-dependent conductivity degradation. To address the thermodynamic instability of ESB, we developed a novel thin and dense ESB/YSZ bilayered electrolyte using nano-sized ESB powders on anode-supported cells, demonstrating high power density SOFC with high efficiency at intermediate temperatures (< ~750 oC). In addition, we dramatically enhanced the kinetic stability of stabilized bismuth oxides via substituting Bi3+ with very small amounts of the secondary aliovalent dopant. In order to investigate the effect of the aliovalent dopants on suppressing the time-dependent degradation mechanism, the cation diffusivity of the samples was evaluated by Boltzmann-Matano method, and chemical and structural changes by extended annealing were also investigated. The electrochemical performance and the stability of the SOFCs with our novel bismuth oxides were evaluated with I-V characteristics and impedance spectroscopy.

Enhancing performance of stabilized bismuth oxide-based cathodes via infiltration process for LT-SOFCs

2025-07-24T07:24:47Z

Title: Enhancing performance of stabilized bismuth oxide-based cathodes via infiltration process for LT-SOFCs Author(s): Park, Jin Wan; Yun, Byeong Hyeon; Joh, Dong Woo; Lee, Kang Taek Abstract: Nanostructured La0.8Sr0.2MnO3-δ (LSM) - Er0.4Bi1.6O3 (ESB) composite cathodes for lower temperature solid oxide fuel cells (LT-SOFCs) were developed via infiltration process. The perovskite phase of LSM nanoparticles deposited on the porous ESB scaffold was confirmed by X-ray diffraction (XRD). The microstructural evolution of the established nanostructures was observed using scanning electron microscope (SEM). The cathodic polarization resistances of the developed cathodes on GDC were measured by electrochemical impedance spectroscopy (EIS) and compared to the conventional LSM-ESB composite cathodes. The resultant area specific resistance (ASR) of the LSM infiltrated ESB cathodes was 1.24 Ω-cm2 at 600°C, which is ∼34% lower than that of the conventional LSM-ESB composite cathode (1.88 Ω-cm2), primarily due to enhanced ORR activities with increased TPB density in the nanostructured cathodes. © The Electrochemical Society.

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Superionic Conducting Bismuth Oxide-Based Electrolytes for Solid Oxide Fuel Cells

Enhancing performance of stabilized bismuth oxide-based cathodes via infiltration process for LT-SOFCs