Research on Electrocatalytic Centers in Gas Diffusion Electrodes By SECM

Due to the higher energy density, compared to state of the art lithium-ion-technology, lithium-air-batteries have raised hope for application, especially in the field of electric mobility. The functionality of lithium-air-batteries is based on the reduction of oxygen within a gas diffusion electrode. The ideal reaction product is lithium peroxide. This process is reversed when charging the battery and can be affected by catalysts. Due to the fact that organic electrolytes are used, different intermediates can be generated during the reduction of oxygen ^[1,2]. These intermediates are highly reactive and may lead to the degradation of the gas diffusion electrode and/or the organic electrolyte. Furthermore, lithium peroxide formed during discharge is known to clog the pores of gas diffusion electrodes before the discharge process is completed ^[3]. In order to avoid these effects, further research is essential.
In our approach we developed a setup which allows monitoring the oxygen permeability of the gas diffusion electrode while discharging (oxygen reduction reaction). The process of clogging as well as the mechanisms of charging in gas diffusion electrodes in organic electrolytes are investigated using positionable microelectrodes in a SECM setup (scanning electrochemical microscopy).

References:

[1]  McCloskey, B.D. et al., J. Phys. Chem. Lett,. 2011, 2, 1161-1166

[2]  Wu, X. et al., Jounal of Power Sources, 2011, 196, 9631-9639

[3]  Read, J., J. Electrochem. Soc., 2002, 149,  9,  A1190-A1195