| 1. |
- Jannat, Sharif, et al.
(författare)
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Preparation and performance of nanometric Ti/TiN multi-layer physical vapor deposited coating on 316L stainless steel as bipolar plate for proton exchange membrane fuel cells
- 2019
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 435
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Tidskriftsartikel (refereegranskat)abstract
- The current research mainly focuses on surface properties, corrosion resistance and interfacial contact resistance (ICR) of nanometric titanium/titanium nitride (Ti/TiN) multi-layer coating deposited on 316L stainless steel via physical vapor deposition (PVD) technique for using in proton exchange membrane fuel cell (PEMFC) bipolar plate (BPP) application. The phase and microstructure of the coated BPPs is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle examinations. The performance of the BPPs is investigated by electrochemical corrosion tests including electrochemical impedance spectroscopy (EIS), potentiodynamic and potentiostatic polarization tests at two conditions including at ambient temperature and in the simulated PEMFC cathode environment. Electrochemical test results reveal that the Ti/TiN coating increases the polarization resistance of 316L stainless steel by 26 orders of magnitude at ambient temperature and by 1000 orders of magnitude in the simulated PEMFC cathode environment. The corresponding ICR of the BPPs is measured ex-situ in a PEMFC set-up. It is observed that the coated BPP has ICR value of 11 and 18 m Omega cm(2) before and after potentiostatic polarization, respectively. Hence, the Ti/TiN coating studied in this work has promising properties as BPP material and is potentially suitable alternative to replace the graphite BPP in PEMFC.
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| 2. |
- Rashtchi, Hamed, et al.
(författare)
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Evaluation of Ni-Mo and Ni-Mo-P Electroplated Coatings on Stainless Steel for PEM Fuel Cells Bipolar Plates
- 2016
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Ingår i: Fuel Cells. - : John Wiley & Sons. - 1615-6846 .- 1615-6854. ; 16:6, s. 784-800
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Tidskriftsartikel (refereegranskat)abstract
- Stainless steel bipolar plates (BPPs) are the preferred choice for proton exchange membrane fuel cells (PEMFCs); however, a surface coating is needed to minimize contact resistance and corrosion. In this paper, Ni–Mo and Ni–Mo–P coatings were electroplated on stainless steel BPPs and investigated by XRD, SEM/EDX, AFM and contact angle measurements. The performance of the BPPs was studied by corrosion and conduction tests and by measuring their interfacial contact resistances (ICRs) ex situ in a PEMFC set-up at varying clamping pressure, applied current and temperature. The results revealed that the applied coatings significantly reduce the ICR and corrosion rate of stainless steel BPP. All the coatings presented stable performance and the coatings electroplated at 100 mA cm−2showed even lower ICR than graphite. The excellent properties of the coatings compared to native oxide film of the bare stainless steel are due to their higher contact angle, crystallinity and roughness, improving hydrophobicity and electrical conductivity. Hence, the electroplated coatings investigated in this study have promising properties for stainless steel BPPs and are potentially good alternatives for the graphite BPP in PEMFC.
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| 3. |
- Rashtchi, Hamed, et al.
(författare)
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Performance of a PEM fuel cell using electroplated Ni–Mo and Ni–Mo–P stainless steel bipolar plates
- 2017
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Ingår i: Journal of the Electrochemical Society. - : Electrochemical Society. - 0013-4651 .- 1945-7111. ; 164:13, s. F1427-F1436
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Tidskriftsartikel (refereegranskat)abstract
- The performance and durability of 316L stainless steel bipolar plates (BPP) electroplated with Ni–Mo and Ni–Mo–P coatings are investigated in a proton exchange membrane fuel cell (PEMFC), using a commercial Pt/C Nafion membrane electrode assembly (MEA). The effect of the BPP coatings on the electrochemical performance up to 115 h is evaluated from polarization curves, cyclic voltammetry and electrochemical impedance spectroscopy together with interfacial contact resistance (ICR) measurements between the coatings and the gas diffusion layer. The results show that all the coatings decrease the ICR in comparison to that of uncoated 316L BPP. The Ni-Mo coated BPP shows a low and stable ICR and the smallest effects on MEA performance, including catalyst activity/usability, cathode double layer capacitance, and membrane and ionomer resistance build up with time. After electrochemical evaluation, the BPPs as well as the water effluents from the cell are examined by Scanning Electron Microscopy, Energy Dispersive and Inductively Coupled Plasma spectroscopies. No significant degradation of the coated surface or enhancement in metal release is observed. However, phosphorus addition to the coating does not show to improve its properties, as deterioration of the MEA and consequently fuel cell performance losses is observed.
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