Abstract
Nickel/zirconia-based nanostructured electrodes for solid oxide fuel cells suffer from poor stability even at intermediate temperature. This study quantifies the electrochemical and microstructural degradation of nanostructured electrodes by combining 3D tomography, electrochemical impedance spectroscopy (EIS) and mechanistic modeling. For the first time, the electrochemical degradation of nanostructured electrodes is quantified according to the fractal nature of the three-phase boundary (TPB). Using this hypothesis an excellent match between modeling and the electrochemical response is found. The origin of the degradation in microstructure and electrochemical performance can be found in the initial fractal roughness of the TPB at a length scale not detectable with state-of-the-art tomography at 30nm resolution. This additionally implies that the hydrogen electro-oxidation takes place within 4nm from the geometric TPB line, revealing that the electrochemical reaction zone cannot be regarded anymore as a one-dimensional line when dealing with nanoparticles.
Highlights
Solid oxide fuel cells (SOFCs) are highly efficient devices that produce electric energy from the direct electrochemical conversion of a wide range of gaseous fuels, such as hydrogen and methane [1,2]
SOFCs rely on the conduction of oxygen ions, from cathode to anode, through a solid ceramic electrolyte, such as yttria-stabilized zirconia (YSZ) or scandia-stabilized zirconia (ScSZ) [5]
The electrochemical degradation of the anodes was measured using real-time impedance spectroscopy in symmetric cells at 550 °C under 5% H2/3% H2O at open-circuit voltage (OCV)
Summary
Solid oxide fuel cells (SOFCs) are highly efficient devices that produce electric energy from the direct electrochemical conversion of a wide range of gaseous fuels, such as hydrogen and methane [1,2]. This technology is expected to play a key role in low-carbon electricity generation due to its capability to flexibly provide electric power with minimal losses, low emissions of pollutants and low levels of noise [3,4]. For some electrolyte materials and geometries, this results in operating temperatures above 800 °C if internal resistive losses are to be minimized. Reducing the operating temperature to the range 500–750 °C can pave the way for more cost-effective SOFCs for residential and transport applications [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
