Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells


Over the past several years, important strides have been made in demonstrating protonic ceramic fuel cells (PCFCs). Such fuel cells offer the potential of environmentally sustainable and cost-effective electric power generation. However, their power outputs have lagged behind predictions based on their high electrolyte conductivities. Here we overcome PCFC performance and stability challenges by employing a high-activity cathode, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF), in combination with a chemically stable electrolyte, BaZr0.4Ce0.4Y0.1Yb0.1O3 (BZCYYb4411). We deposit a thin dense interlayer film of the cathode material onto the electrolyte surface to mitigate contact resistance, an approach which is made possible by the proton permeability of PBSCF. The peak power densities of the resulting fuel cells exceed 500 mW cm−2 at 500 °C, while also offering exceptional, long-term stability under CO2.

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Fig. 1: Selected characteristics of the electrolyte material BZCYYb4411.
Fig. 2: H2O uptake behavior of PBSCF.
Fig. 3: Scanning electron microscopy images of PBSCF/BZCYYb4411/cermet anode fuel cell.
Fig. 4: Electrochemical properties of the PBSCF cathode based on BZCYYb4411 proton conducting electrolyte using humidified (3% H2O) H2 as fuel and dry air as oxidant at various temperatures.
Fig. 5: Electrochemical behavior of microdot PBSCF at 500 °C under lightly humidified synthetic air as determined from a.c. impedance spectroscopy.


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This research was funded in part by the US Department of Energy, through ARPA-e Contract DE-AR0000498, via subcontract from United Technologies Research Center, and by the National Science Foundation, DMR-1505103. Selected facilities used were supported by the National Science Foundation via Northwestern University’s MRSEC, DMR-1121262.

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S.M.H led the development of the concept, guided the experimental design, and supervised the research. S.C. developed the materials, fabricated the cells, and performed the following experiments and analyses: conductivity, thermogravimetry, fuel cell polarization, and impedance spectroscopy. Y.L. and X.Z. prepared and characterized PLD microdot electrodes, on which C.J.K. performed electrochemical measurements. I.T. supervised PLD film growth and characterization. H.-I. J. provided critical suggestions for experimental and analytical methods. S.M.H. and S.C. wrote the paper with contributions from all authors.

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Correspondence to Sossina M. Haile.

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Supplementary Figures 1–15, Supplementary Table 1 and Supplementary References

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Choi, S., Kucharczyk, C.J., Liang, Y. et al. Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells. Nat Energy 3, 202–210 (2018). https://doi.org/10.1038/s41560-017-0085-9

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