SPEAKER:
Professor Enrico Traversa, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Saudi Arabia
SYNOPSIS:
The development of alternative and renewable solar and photovoltaic power supply devices is attracting increasing attention for a sustainable future. However, solar power is intermittent and site-specific. Leverage of continuous energy supply needs to be achieved with the integration of energy storage systems in the grid. One possibility is the use of solid oxide electrolysis cells (SOECs), solid oxide fuel cells (SOFCs) operating in reverse, which are high temperature energy storage devices that convert heat and electrical power into chemical energy by producing hydrogen from steam. Hydrogen is attractive as energy carrier and as a clean fuel for a number of applications. Conventional SOECs use oxygen-ion conducting electrolytes, which show problems such as the need of separating produced H2 from unreacted H2O, cell performance degradation due to the oxidation of hydrogen electrode, low current efficiency during the electrolysis process, etc.
This talk will discuss using high temperature proton-conducting oxide electrolytes as an alternative that may solve some of the current issues for both SOFCs and SOECs, due to their low activation energy for proton conduction (0.3-0.6 eV). Moreover, proton conductor electrolytes offer the advantage of generating water at the air electrode, and thus the fuel does not become diluted during fuel cell operation [1], and dry H2 is produced in electrolysis mode, which also prevents Ni oxidation.
The main problem of proton-conducting electrolytes is their chemical stability in the presence of steam and carbon-based fuels. We have recently made significant progresses in the electrolyte development by improving the conductivity of Y-doped barium zirconate (BZY) [2]: doped BaZrO3 offer excellent chemical stability against CO2 and H2O reaction, but low conductivity values for sintered pellets are usually reported. We followed various strategies to improve the BZY conductivity [3-10]. The possibility to develop a next generation of devices, though, needs also developing electrode materials [11]. Our recent work in studying tailored cathode [12-14] and anode materials [15-17] will be also presented. Finally, the new and necessary direction for the research on proton-conducting SOECs will be discussed, which is the development of film electrolytes made of chemically stable proton-conducting oxides [18].
[1] E. Fabbri, D. Pergolesi, E. Traversa, Chem. Soc. Rev. 29, 4355 (2010).
[2] D. Pergolesi et al., Nature Mater. 9, 846 (2010).
[3] E. Fabbri, L. Bi, D. Pergolesi, E. Traversa, Adv. Mater. 24, 195 (2012).
[4] L. Bi, E. Traversa, J. Mater. Res. 29, 1 (2014).
[5] E. Fabbri, L. Bi, H. Tanaka, D. Pergolesi, E. Traversa, Adv. Funct. Mater. 21, 158 (2011).
[6] Z.Q. Sun, E. Fabbri, L. Bi, E. Traversa, Phys. Chem. Chem. Phys. 13, 7692 (2011).
[7] Z.Q. Sun, E. Fabbri, L. Bi, E. Traversa, J. Am. Ceram. Soc. 95, 627 (2012).
[8] L. Bi, E. Fabbri, Z.Q. Sun, E. Traversa, Energy Environ. Sci. 4, 409 (2011).
[9] E. Fabbri et al., Energy Environ. Sci. 3, 618 (2010).
[10] D. Pergolesi, E. Fabbri, E. Traversa, Electrochem. Commun. 12, 977 (2010).
[11] E. Fabbri, D. Pergolesi, E. Traversa, Sci. Technol. Adv. Mater. 11, 044301 (2010).
[12] E. Fabbri, I. Markus, L. Bi, D. Pergolesi, E. Traversa, Solid State Ionics 202, 30 (2011).
[13] E. Fabbri, L. Bi, D. Pergolesi, E. Traversa, Energy Environ. Sci. 4, 4984 (2011).
[14] L. Bi, E. Fabbri, E. Traversa, Solid State Ionics 214, 1 (2012).
[15] L. Bi, E. Fabbri, Z.Q. Sun, E. Traversa, Energy Environ. Sci. 4, 1352 (2011).
[16] L. Bi, E. Fabbri, Z.Q. Sun, E. Traversa, J. Electrochem. Soc. 158, B797 (2011).
[17] L. Bi, E. Fabbri, E. Traversa, Electrochem. Comm. 16, 37 (2012).
[18] L. Bi, S. Boulfrad, E. Traversa, Chem. Soc. Rev. DOI: 10.1039/C4CS00194J (2014).