Protonic ceramic electrochemical cells (PCECs) can be employed for power generation and sustainable hydrogen production. Lowering the PCEC operating temperature can facilitate its scale-up and commercialization. However, achieving high energy efficiency and long-term durability at low operating temperatures is a long-standing challenge. Here, we report a simple and scalable approach for fabricating ultrathin, chemically homogeneous, and robust proton-conducting electrolytes and demonstrate an in situ formed composite positive electrode, Ba0.62Sr0.38CoO3−δ–Pr1.44Ba0.11Sr0.45Co1.32Fe0.68O6−δ, which significantly reduces ohmic resistance, positive electrode–electrolyte contact resistance and electrode polarization resistance. The PCECs attain high power densities in fuel-cell mode (~0.75 W cm−2 at 450 °C and ~0.10 W cm−2 at 275 °C) and exceptional current densities in steam electrolysis mode (−1.28 A cm−2 at 1.4 V and 450 °C). At 600 °C, the PCECs achieve a power density of ~2 W cm−2. Additionally, we demonstrate the direct utilization of methane and ammonia for power generation at <450 °C. Our PCECs are also stable for power generation and hydrogen production at 400 °C.
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This work was financially supported by the Nissan Motor Co., Ltd (A22-0455-001, C.D.), Department of Energy grants (DE-FE0032005, DE-SC0021505, DE-FE0032235 and DE-FE0032300, C.D.) and a National Aeronautics and Space Administration grant (80NSSC21C0220, C.D.). Some of the work was performed in following core facility, which is a part of Colorado School of Mines’ Shared Instrumentation Facility (Electron Microscopy: RRID:SCR_022048).
Part of this work is financially supported by the Nissan Motor Co., Ltd (A22-0455-001). The funder participates in the decision to publish and preparation of the manuscript. Co-authors M.H.A.J., C.G., Y.F. and N.D. are employed at Nissan Technical Centre North America (NTCNA), Farmington Hills, MI, USA. Co-authors T.O. and M.U. are employed at Nissan Research Center, Nissan Motor Company Limited, Yokosuka, Japan.
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Supplementary Notes 1–4, Figs. 1–41, Tables 1–8 and references.
Atomic coordinates (POSCARs) of bulk structures, structures with oxygen vacancies, and initial and final states of oxygen diffusion calculations OF BSC, PBSCF-1 and PBSCF-2.
A demonstration of green hydrogen production at 400 °C.
Button PCEC electrolyte ultrasonic spray coating.
Large-area PCEC electrolyte ultrasonic spray coating.
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Liu, F., Deng, H., Diercks, D. et al. Lowering the operating temperature of protonic ceramic electrochemical cells to <450 °C. Nat Energy 8, 1145–1157 (2023). https://doi.org/10.1038/s41560-023-01350-4