Protonic ceramic electrochemical cells (PCECs) are promising solid-state energy conversion devices which enable the conversion of energy between electricity and hydrogen at intermediate temperatures. Rapid conversion between chemical and electrical energy via PCEC technology will assist in overcoming grand challenges in energy storage. To achieve highly efficient reversible operation between hydrogen production and electricity generation, boosting water-oxidation and oxygen reduction activities of the oxygen electrode while maintaining the durable operation is one of the early-stage technical opportunities. In this study, an A-site deficient layered perovskite (PrBa_0.8Ca_0.2)_0.95Co₂O_6−δ has been developed as an oxygen electrode for a PCEC which presents superior electrochemical performances. The electrolysis current density reached as high as −0.72 A cm⁻² at 1.3 V, and a peak power density of 0.540 W cm⁻² was obtained at 600 °C in electrolysis and fuel cell mode, respectively. The PCEC with the new electrode shows good durability under practical operating conditions for 160 hours in both operating modes with no observable degradation. The reversibility between the electrolysis and fuel cell mode is also successfully demonstrated.

Amorphous molybdenum disulfide (MoS ₂ ) is a promising electrochemical catalyst for hydrogen evolution reaction (HER) due to more active sites exposed on the surface compared to its crystalline counterpart. In this study, a novel fast three-minute one-pot method is proposed to prepare the single-wall carbon nanotube- (SWCNT-) supported amorphous MoS ₂ via a microwave heating process. Compared to traditional hydro- or solvent thermal methods to prepare MoS ₂ which usually consume more than 10 hours, it is more promising for fast production. An overpotential at 10 mA/cm ² of amorphous MoS ₂ @SWCNT is 178 mV, which is 99 mV and 22 mV lower than crystalline MoS ₂ @SWCNT and pure amorphous MoS ₂ , respectively. After running 1000 cycles of polarization, ~2% increase in overpotential is observed, indicating its good stability. The enhanced performance results from the beneficial combination of the SWCNT substrate and the amorphous microstructures. The introduction of SWCNT increases catalyst conductivity and prevents MoS ₂ aggregation. The amorphous microstructures of MoS ₂ prepared by a microwave heating method lead to more Mo edges or active sites exposed.

Developing protonic ceramic fuel cells is regarded as a promising approach for the electrochemical conversion of the chemical energy in hydrogen to power with high efficiency. Lowering the operating temperature can accelerate its application by integrating more reliable stack components to enable long-term durability. One critical pathway is to facilitate the oxygen reduction reaction via developing triple conducting oxygen electrodes for increasing active sites for catalysis and charge transport in bulk and interface, aiming to improve reaction kinetics. In this work, the recently developed triple conducting oxygen electrode PrNi_0.7Co_0.3O_3−δ has been examined under dynamic operating conditions to understand the degradation behaviors through an accelerated stress test. Various test protocols have been employed to measure and compare the mechanical and electrochemical performances under different dynamic parameters and thermal cycling conditions. The results strongly indicate that the as-fabricated cells exhibit a high level of endurance despite a slightly increased polarization resistance and an accelerated stress test is an effective way to examine cell reliability under more dynamic kinetics.