In this work we present a carbon free gas diffusion electrode (GDE) design. It is a first step towards improvement of technologies
like alkaline fuel cells, some alkaline electrolyzes and metal-air-batteries by circumventing carbon degradation. A nickel-mesh was
made hydrophobic and subsequently electrochemically coated with MnOx as electrocatalyst. By this, a carbon free GDE was
prepared. The contact angle, specific surface area (BET), pore size distribution, crystal phase (XRD) and electrochemical properties
were determined. The deposition scan rate (rscan) during dynamic MnOx deposition altered the macro surface structure, pore size
distribution and deposited mass. High catalyst masses with high specific surface area were achieved by lower rscan, but
hydrophobicity was decreased. Impedance spectroscopy showed that higher MnOx mass will increase the ohmic resistance, because
of the low conductivity of oxides, such as MnOx. The diffusion of dissolved oxygen is the major contributor to the total resistance.
However, the polarization resistance was reduced by increased specific surface area of MnOx. It was concluded that the ORR
and OER are limited by diffusion in this design but nevertheless showed reasonable activity for ±10 mA cm−2 corresponding to
∼8 Ω cm−2 while references exhibited ∼3.5 Ω cm−2
.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:85011 |
| Date | 27 April 2023 |
| Creators | Bekisch, Artur, Skadell, Karl, Poppitz, David, Schulz, Matthias, Weidl, Roland, Stelter, Michael |
| Publisher | IOP Publishing |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 144502 |
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