Triple ionic-electronic conducting oxides for next-generation electrochemical devices.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Triple ionic-electronic conductors (TIECs) facilitate simultaneous transport of electronic species and two ionic species.
• Emerging TIECs offer potential for enhanced performance in fuel cells, membrane reactors, and electrolysis cells.
• Current applications are hindered by limited understanding of TIEC transport properties and electrocatalytic activity.

Purpose of the Study:

• To review and analyze the current understanding of transport and electrochemistry in single-phase TIECs.
• To explore defect formation and conduction mechanisms within TIECs.
• To identify discovery criteria, design principles, and operating conditions for tuning TIEC conductivity.

Main Methods:

• Analysis of existing literature on TIEC transport and electrochemistry.
• Focus on defect chemistry and conduction mechanisms.
• Examination of crystal structure, ion electronegativity, cation/anion substitution, and atmospheric effects.

Main Results:

• Summarizes fundamental knowledge of TIEC transport and electrochemistry.
• Details discovery criteria, including crystal structure and ion electronegativity.
• Explains design principles like cation/anion substitution and the impact of operating conditions.

Conclusions:

• Highlights the need for further research into higher chemical stability and lower operating temperatures for TIECs.
• Emphasizes the importance of discovering new n-type TIEC materials.
• Identifies key areas for advancing TIEC technology for electrochemical applications.