Innovators at Chinese Academy of Sciences’ Dalian Institute of Chemical Physics (DICP) have achieved an impressive breakthrough. These efforts are elucidating the importance of A-site cation ordering in perovskite anodes for solid oxide electrolysis cells (SOECs). The research team led by Prof. Song Yuefeng synthesized two novel perovskite anodes, i.e., PrBaCo2O5+δ (PBCO-1.0) and Pr1.5Ba0.5Co2O5+δ (PBCO-1.5). Their purpose was to target the electronic structure and high-temperature kinetics of the oxygen evolution reaction (OER).
The collaborative effort included contributions from Prof. Wang Guoxiong of Fudan University and Prof. Liu Meilin from Georgia Institute of Technology. This research is incredibly important as solid oxide electrochemical cells (SOECs) are among the leading technologies for carbon dioxide reduction and energy conversion. They provide record-breaking current densities, great Faradaic efficiency and low overpotentials.
Synthesis and Analysis of Perovskite Anodes
The researchers used a two-step synthesis process to produce the two different AnTs with different praseodymium (Pr) concentrations. This is the structure of the 1.0 Pr PBCO-1.0, the 1.5 Pr PBCO-1.5 structure. Such variations have proven to be invaluable in elucidating the role of A-site cation ordering on the material properties that are important for high-temperature applications.
Throughout the study, the research team put compounds through rigorous testing to ensure the anodes entirely maintained their high-temperature OER activity and stability. At an operating temperature of 800°C and a voltage of 1.6 V, the PBCO-1.5 anode showed a high current density of 2.29 A cm -2. The results speak for themselves—it’s pretty great. This performance highlights the promise of PBCO-1.5 for efficient operations in SOECs.
Structural Insights and Phase Transition
A major aspect of this research was the shift in crystal structure as the Pr content increased. The study noted that the PBCO-1.0 exhibited an ordered tetragonal phase (P4/mmm), while the PBCO-1.5 transitioned to a disordered orthorhombic phase (Pnma). This structural change is very important. Therefore, it directly influences the electronic properties and performance of the anodes in high-temperature condition.
This research sheds light on some of the molecular-level mechanisms that dictate anodic high-temperature OER in SOECs. Understanding these mechanisms will be key to developing better materials that improve energy conversion processes.
Publication and Future Implications
The researchers published their results in the Journal of the American Chemical Society. Their work provides a complete picture and points to important implications for future research within this growing field. The DOI of the published research is 10.1021/jacs.5c09331.