Abstract:

Polytetrafluoroethylene (PTFE) emulsion used as a binder for gas diffusion electrodes was pretreated with ethanol before use in electrodes. The surface topography of the gas diffusion electrodes was characterized by scanning electron microscopy (SEM). The BET and Langmuir special surface areas and pore distribution of the gas diffusion electrode were measured using a surface area detector. A zinc-air battery was then assembled and included this pretreated gas diffusion electrode. Under different current densities, the potential changes of the gas diffusion electrodes vs a zinc anode was measured. The impact of the PTFE emulsion alcoholic pretreatment on the performance of the gas diffusion electrodes was studied. The experimental results show that the porous structure of the catalytic activity layers and the gas diffusion layers increase with pretreatment. The reaction zones also increase with an increase in the catalytic activity of the layer's porous structure. Transport of the reactant gas is easier as the porous structure of the gas diffusion layers increase. The polarization potential of the gas diffusion electrode working under a large current density thus decreased.

Key words: Gas diffusion electrode, Ethanol, Polytetrafluoroethylene emulsion, Gas diffusion layer, Catalytic activity layer, Porous structure, Special surface area