FES Funded ProjectsOutputs
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Saturation Behaviour of Atomic Layer Deposition MnOx from Bis (Ethylcyclopentadienyl) Manganese and Water: Saturation Effect on Coverage of Porous Oxygen Reduction ElectrodesMnOx deposits on porous gas diffusion layer (GDL) substrates for application as catalysts for the oxygen
reduction reaction (ORR) in metal−air batteries have been prepared using atomic layer deposition (ALD). The saturation behavior of the bis(ethylcyclopentiadienyl) manganese ((EtCp)2Mn) and H2O ALD system has been investigated. The observed saturation behavior is in disagreement with previous reports in literature. (EtCp)2Mn + H2O depositions exhibited non-ALD behavior, as demonstrated by a high growth per cycle (GPC) at substrate temperatures (Tsub) = 40−50 °C and nonsaturating reactions at Tsub ≥ 60 °C. The introduction of a forming gas (FG) (95% N2 + 5% H2) plasma between the (EtCp)2Mn and H2O doses promoted precursor saturation with a constant GPC (1.15 Å/cy) in the Tsub range of 100−200 °C. The effect of saturation behavior on porosity coverage was investigated by coating porous carbon electrodes with ALD MnOx. Energy dispersive X-ray (EDX) spectroscopy, electrochemical surface area measurements, and oxygen reduction activity all indicate that the saturating behavior of the (EtCp)2Mn + FG + H2O deposition resulted in superior coverage compared with the (EtCp)2Mn + H2O depositions.T06-P03 University of Alberta | Publication | 2018-12-19 | Michael Clark, Ming Xiong, Ken Cadien, Ivey, D. | High Performance Oxygen Reduction/Evolution Electrodes for Zinc-Air Batteries Prepared by Atomic Layer Deposition of MnOxOxygen reduction electrodes for zinc–air batteries (ZAB) have been prepared by depositing conformal films of MnOx directly onto high surface area gas diffusion layers (GDL) via atomic layer deposition (ALD). MnOx films were prepared by means of two deposition conditions: one using a forming gas (95% N2, 5% H2) plasma (FG-MnOx) and one using an O2 plasma (O2-MnOx). A composite electrode of FG-MnOx + CoOx was also examined. The conformal nature of ALD films allowed for MnOx to be deposited within the porosity of the GDL, as confirmed by X-ray microanalysis. Full cell ZAB tests showed excellent performance for MnOx-coated electrodes, outperforming Pt/Ru–C at current densities larger than 100 mA cm–2. Annealed FG-MnOx and O2-MnOx electrodes had maximum power densities of 170 and 184 mW cm–2, respectively. With the catalyst distributed within the structure of the GDL, performance limitations associated with electrolyte flooding and air diffusion are reduced, improving discharge potential and cycling behavior. FG-MnOx + CoOx electrodes showed good cycling stability, both in a trielectrode configuration and bifunctionally. When cycled at 20 mA cm–2 for 100 h (200 cycles), FG-MnOx + CoOx had initial and final discharge potentials of 1.18 and 1.15 V, respectively.T06-P03 University of Alberta | Publication | 2020-04-01 | Michael Clark, Ming Xiong, Ken Cadien, Ivey, D. | Atomic Layer Deposition of Iron Oxide on a Porous Carbon Substrate via Ethylferrocene and an Oxygen PlasmaEthylferrocene, a novel precursor for atomic layer deposition (ALD) of iron oxide, was investigated using an oxygen plasma co-reactant. Iron oxide deposition showed a saturating growth rate of 0.1 Å/cycle in the temperature range of 150°C to 250°C. The iron oxide coating was subsequently deposited on a porous gas diffusion layer (GDL) for use as an air electrode in a zinc-air battery. X-ray microanalysis confirmed deep penetration of the iron oxide into the porosity of the GDL, with a lower substrate temperature providing deeper coverage. Transmission electron microscopy revealed that a uniform 10 nm thick iron oxide coating encased the GDL particles. Electron diffraction and X-ray photoelectron spectroscopy identified the iron oxide film as -Fe2O3. Electrochemical characterization of the ALD-coated GDL showcased promising catalytic activity towards the oxygen evolution reaction.T06-P03 University of Alberta | Publication | 2021-09-15 | Matthew Labbe, Michael Clark, "Zahra Abedi ", "Anqiang He ", Ken Cadien, Ivey, D. | Atomic Layer Deposition of Transition Metal Oxide Catalysts for Zinc-Air BatteriesTwitter poster and oral presentation as part of the FES Fall Symposium 2021.T06-P03 University of Alberta | Activity | 2021-09-14 | | Growth of Multiple Island Layers during Iron Oxide Atomic Layer Deposition: An Electron Microscopy and Spectroscopic Ellipsometry InvestigationAtomic layer deposition (ALD) of FeOx thin films, prepared using the air stable and low cost precursor of ethylferrocene, was characterized through electron microscopy and spectroscopic ellipsometry (SE) techniques. To model the growth behavior of the layer on carbon-based air electrodes in metal–air batteries, carbon substrates were employed for electron microscopy. Electron imaging revealed an island morphology for the FeOx deposits, which eventually coalesced into a continuous film with pinholes. Further growth resulted in another layer of islands forming on top of the continuous film, in a process that was repeated throughout deposition. In situ SE exhibited both substrate-enhanced and substrate-inhibited characteristics; the former was due to a MnOx seed layer deposited prior to FeOx ALD, while the latter was a consequence of the island growth mode. After an extended number of ALD cycles, the process entered a linear growth regime, which is typically associated with layer-by-layer growth. The application of an effective medium approximation model to the SE data revealed the nucleation of six different layers of FeOx islands through 650 ALD cycles. This novel work showcases the need for multiple characterization techniques to confirm the growth mode displayed by an ALD process.T06-P03 University of Alberta | Publication | 2022-11-10 | | Zinc-Air Battery Advances: Efficiency, Stability, and Low Temperature OperationPoster presentation on progress in Ivey Group on zinc-air batteries.T06-P03 University of Alberta | Activity | 2023-04-28 | | Growth Behaviour of Iron Oxide using Atomic Layer DepositionPresentation dealing with modelling of atomic layer deposition of iron oxide for use as a catalyst for the air electrode in zinc-air batteries. T06-P03 University of Alberta | Activity | 2022-06-14 | | Atomic Layer Deposition of Highly Stable Manganese-Iron Oxide Bifunctional Catalysts for Zinc-Air BatteriesAtomic layer deposition of manganese-iron oxide bifunctional catalysts for the air electrode for zinc-air batteriesT06-P03 University of Alberta | Activity | 2022-05-31 | |
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