LuZi: Bifunctional catalysts and gas diffusion electrodes for the electrical rechargeable zinc/air battery

Background

Primary zinc-air batteries are widely utilized in hearing aids devices as energy supply source because of their extremely high practical capacity and energy density of about 700 mAh and 845 mWh per gram zinc, respectively [1]. However, commercialization of rechargeable Zn/air batteries are actually hindered by some inherent drawbacks related to the metal electrode such as poor reversibility, formation of passive layer, shape change and dendrite formation as well as low energy efficiency (< 60%) due to high overpotential and carbonate precipitation at the air electrode in alkaline electrolyte. In this context, recent developments of ionic liquids (IL) based aprotic/protic electrolytes open exciting perspectives [2], especially with respect to suppression of dendrites, passive layer and carbonate formation. However, one of the most challenging issues is related to the air electrode reactions (ORR/OER) in ILs. A Zn/air button cell design is shown in figure 1

 Figure1: Zinc/air button cell with a PVA/KOH/TiO2 membrane [1]

Objectives

“LuZi” project aims at the development of a secondary zinc/air battery with appropriate IL-based electrolytes. DFI activities focus on screening, development and characterization of active and stable bifunctional catalysts and gas diffusion electrodes (GDE) for the direct electric rechargeable zinc/air battery in alkaline and IL-based electrolytes.

Acknowledgements

Federal Ministry of Education and Research (BMBF) is gratefully acknowledged for financial support (Förderkennzeichen: 03SF0499B)

Literature

[1] A. Herter, V.M. Schmidt, J.-F. Drillet; Patent WO 2013 000584 A1 (2013)
[2] Y. Li, H Dai; Recent advances in zinc–air batteries, Chem. Soc. Rev. 43 (2014) 5257
[3] E. E. Switzer et al.; Oxygen reduction reaction in Ionic Liquids: The addition of protic species, J. Phys. Chem. C 117 (2013) 8683−8690