Analyzing transport paths in the air electrode of a zinc air battery using X-ray tomography

• Zinc air battery discharge was monitored with X-ray tomography.
• A special zinc air battery design for tomography was developed.
• Redistribution of electrolyte during discharge causes flooding or pores in the GDL.
• Early battery EOL due to blocked air transport paths is reported for the first time.

X-ray tomography was used to investigate the discharge behavior of a zinc air battery in-operando. A special battery set-up and preparation was used in order to meet both electrochemical and tomographic requirements. The prepared battery was discharged galvanostatically and analyzed with tomographic measurements at a state of charge of 100%, 75% and 65%. End-of-life of the investigated zinc air battery is reached much earlier than the amount of active zinc particles would allow. This is attributed to an observable blockage of oxygen transport paths in the gas diffusion layer caused by increased flooding with liquid.