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Switching on electrocatalytic activity in solid oxide cells

Nature volume 537, pages 528531 (22 September 2016) | Download Citation

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Abstract

Solid oxide cells (SOCs) can operate with high efficiency in two ways—as fuel cells, oxidizing a fuel to produce electricity, and as electrolysis cells, electrolysing water to produce hydrogen and oxygen gases. Ideally, SOCs should perform well, be durable and be inexpensive, but there are often competitive tensions, meaning that, for example, performance is achieved at the expense of durability. SOCs consist of porous electrodes—the fuel and air electrodes—separated by a dense electrolyte. In terms of the electrodes, the greatest challenge is to deliver high, long-lasting electrocatalytic activity while ensuring cost- and time-efficient manufacture1. This has typically been achieved through lengthy and intricate ex situ procedures. These often require dedicated precursors and equipment1,2,3; moreover, although the degradation of such electrodes associated with their reversible operation can be mitigated4, they are susceptible to many other forms of degradation5. An alternative is to grow appropriate electrode nanoarchitectures under operationally relevant conditions, for example, via redox exsolution6,7,8,9,10. Here we describe the growth of a finely dispersed array of anchored metal nanoparticles on an oxide electrode through electrochemical poling of a SOC at 2 volts for a few seconds. These electrode structures perform well as both fuel cells and electrolysis cells (for example, at 900 °C they deliver 2 watts per square centimetre of power in humidified hydrogen gas, and a current of 2.75 amps per square centimetre at 1.3 volts in 50% water/nitrogen gas). The nanostructures and corresponding electrochemical activity do not degrade in 150 hours of testing. These results not only prove that in operando methods can yield emergent nanomaterials, which in turn deliver exceptional performance, but also offer proof of concept that electrolysis and fuel cells can be unified in a single, high-performance, versatile and easily manufactured device. This opens up the possibility of simple, almost instantaneous production of highly active nanostructures for reinvigorating SOCs during operation.

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Change history

  • 21 September 2016

    In Fig. 2a, ‘H2O/H2’ was replaced with ‘H2O/N2’.

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Acknowledgements

We acknowledge support from the Engineering and Physical Sciences Research Council (EPSRC) Platform (grant EP/K015540/1), the EPSRC Material World Network (EP/J018414/1), EPSRC SUPERGEN Projects (EP/K021036/1 and EP/G01244X/1), EPSRC Capital for Great Technologies grant (EP/L017008/1) and a Royal Society Wolfson Merit Award (WRMA 2012/R2).

Author information

Author notes

    • Jae-ha Myung
    •  & Dragos Neagu

    These authors contributed equally to this work.

Affiliations

  1. School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST, UK

    • Jae-ha Myung
    • , Dragos Neagu
    • , David N. Miller
    •  & John T. S. Irvine

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Contributions

J.M. fabricated and optimized the cells, and carried out electrochemical testing and analysis. D.N. designed the study with help from J.M., and collected and analysed thermogravimetric analysis (TGA) and scanning electron microscope (SEM) data. D.N.M. collected transmission electron microscope (TEM) data. J.T.S.I. oversaw the study. D.N. wrote the manuscript with assistance from J.M. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Jae-ha Myung or Dragos Neagu or John T. S. Irvine.

Reviewer Information

Nature thanks J.-L. Luo and M. Mogensen for their contribution to the peer review of this work.

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DOI

https://doi.org/10.1038/nature19090

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