fraunhofer institute for solar energy systems ise …
TRANSCRIPT
© Fraunhofer ISE
Dr. A. Georg, U. Groos, Dr. M. Klingele, Dr. S. Metz, Dr. S. Ouardi, Dr. A. Schaadt, Dr. T. Smolinka, M. Zedda
Fraunhofer Institute for Solar Energy Systems ISE
www.h2-ise.com
www.ise.fraunhofer.com
FRAUNHOFER INSTITUTE FOR SOLAR ENERGY SYSTEMS ISE DIVISION »HYDROGEN TECHNOLOGIES«
Ex-situ characterisation tools for materials and components in PEM water electrolysis and fuel cells
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Ex situ analysis of materials and componentsOverview
Inductively coupled plasma mass spectroscopy (ICP –MS) for element analysis of liquids
Capillary flow porometry (CFP) for through-plane gas permeability of porous media
Porosimetry for absolute and relative in-plane gas and liquid permeability
Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-ray Spectroscopy (EDS)
X-ray computed tomography(Micro CT)
Electrical conductivity and interfacial contact resistance (ICR) and force-displacement measurements
High temperature and Near ambient pressure X-ray photoelectron spectroscopy (HT NAP-XPS)
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Capillary flow porometry for porous media
Gas-liquid displacement porometrywith pressure step/stability method:
Determination of pore diameter:
Largest / mean / smallest
Through-plane gas permeability
Relationship capillary pressure vssaturation
Inner (mean) contact angle
Important parameters for PTL design
0.00 0.01 0.02 0.03 0.040.0
0.3
0.6
0.9
1.2
1.5
1.8
Volu
me
flow
Q /
l·min
Pressure p / bar
Wet curve Interpolated dry curve Half interpolated dry curve
0.0 0.2 0.4 0.6 0.8 1.00.00
0.01
0.02
0.03
0.04
0.05
0.06
Capi
llary
pre
ssur
e p c /
bar
Saturation s
1. Measurement 2. Measurement Van Genuchten
Smallestpore
Largestpore
Meanpore
Porolux 1000 from Porometer
Sample holder Contact angle measurement set up
Bromberger, K., Ghinaiya, J., Lickert, T., Fallisch, A., Smolinka, T.: Hydraulic ex situ through-plane characterization of porous transport layers in PEM water electrolysis cells, Int. J. Hydrogen Energy, Vol. 43, Issue 5, 2018, 2556-2569, https://doi.org/10.1016/j.ijhydene.2017.12.042.
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0 100 200 300 400 5000
200
400
600
800
1000
Pres
sure
dro
p ∆ p
/ m
bar
Volume flow Q / l·min
PTL 1 PTL 2 ∆p ∆p κin-plane κin-plane
2x10-12
4x10-12
6x10-12
8x10-12
10-11
Perm
eabi
lity κ
/ m2
In plane permeability of porous media
Absolute and relative in-plane gas and liquid permeability
Test set up with a cell area of 25 cm²
Method established for GDL / PTL etc. using Darcy or Darcy-Forchheimer law
Test set up for in-plane permeability measurements and detailedview on test cell
In-plane pressure difference and gas permeability for different gas flow rates of sintered titanium based PTLs
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Measurement of in-plane and through-plane resistance/conductivity as function of compression
Interfacial Contact Resistance (ICR) of passivation layers
Thickness measurement by eddy current sensors (resolution 3 µm)
Combination of clamping pressure and thickness measurement allows a force/displacement analysis
Electric conductivity and interfacial contact resistanceUnderstanding of internal cell resistance and individual contributions is crucial for stack design
ICR1
Rbulk
ICR24w
Electricalinsulation
Stainlesssteel plate
PTL sample
Pressure
Voltage probe
I2w
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Measurement of through-plane resistance of different materials
Interfacial contact resistance (ICR) between bipolar plate and GDL
Bulk resistance of GDL
Thickness measurement
Through-plane resistance and interfacial contact resistance
Au
Au
coatedBPP
GDL sense (-)
source (-)
source (+) sense (+)
Homogeneouspressure distribution
ICR of uncoated and coated SS 316 L before & afeter electrochemical testing
Measurement principleMeasurement setup
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Inplane & through-plane resistance
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Electrochemical characterization of bipolar plate materials
Cyclic voltammogramm of stainless steel at different temperatures, electrolyte: 0.001 M H2SO4+0.1 mg HF
Electrochemical measurements is combined with elemental analysis of the electrolyte with ICP-MS (here during potentiostatic test at 0.8 V for 4 days), SEM/EDX analysis, and contact resistance measurement.
Test cell made of PTFE, integrated heating, gas (Ar or O2), working electrode (WE) (sample), reference electrode (RHE), counter electrode (CE).
Gaskatel FlexCell®
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Inductively Coupled Plasma – Mass Spectroscopy (ICP-MS)
Element analysis of liquids with ICP-MS. In Ar-plasma the molecules are destroyed and ionised. In the mass spectrometer the ions of every mass are counted.
ICP-MS product water analysis of a fuel cell stackwith metallic bipolar plates (extreme example)
ICP-MS analysis of electrolyte after ex-situ corrosion test (24 h at 0.8 V) of metallic bipolar plates. (ISE-coating comparedwith Au plated and uncoated stainlesssteel substrate)
Agilent MS 7500 ce
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Scanning Electron Microscopy and Computed X-ray Tomography
Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-ray Spectroscopy (EDS) for element analysis
Platinum
Ruthenium
ESEM
Computed X-ray tomography with a nominal resolution of 600 nm
non-destructive scanning and 3D reconstruction of internal micro-structures incl. compression stage
Skyscan 2211 from BrukerFEI Quanta 400 MK II
3D r
eco
nst
ruct
ion
of
a PT
L fo
r PE
M w
ater
el
ectr
oly
sis
Zielke, L., Fallisch, A., Paust, N., Zengerle, R., Thiele S.: Tomography based screening of flow field/currentcollector combinations for PEM water electrolysis. RSC Adv (2014), 10.1039/c4ra12402b
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Fenton testing
Investigating the chemical stability of fuel cell or electrolysis membranes regarding radical attacs
Membrane degradation: cations catalyze radical formation from H2O2 and radicals attac the membrane polymer
Fenton test: Insertion of membrane in 30% H2O2 with metal salts (typically Fe2+) and heat at 80°C
Measurement of Fluoride-release over time as measure for membrane decomposition
F- measurement with ion sensitive electrode
Use of chemical inert polymer bottles (safer and less contamination than glass)
Testing with different temperatures, cations and/or membranes; variation of cation concentration membranes after Fenton-
Test with: I: Al, III: Fe,
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Near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)
X-ray source: AlKα (1.4 keV)
Spot size 300 µm Ø
Pressure:10-8 mbar up to 20 mbar
Sample temperature:5 - 800 °C
Sample size up to 120 mm ∅
Plasma cleaning of the surface
Fully automated vacuum and gas dosing system(N2, Ar, H2, O2)
EnviroESCA(SPECS GmbH)
EnvironESCA: Electron spectroscopy for chemical analysis under environmental conditions at near ambient pressure of catalysts, liquids and liquid-solid interfaces.
Surface characterisation of an IrO2 based anode for PEM water electrolysis as received, after short-term and long-term operation
320 300 2800.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Nor
m. I
nten
sity
Binding energy [eV]
IrO2 Electrode short time long time New Ir 4f7/2Ir 4f5/2
C 1s
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Thanks a lot for your kind attention!
Fraunhofer Institute for Solar Energy Systems ISE
Electrolysis Fuel Cell Systems Thermochemical Systems
Dr. Tom Smolinka Ulf Groos Dr. Achim [email protected] [email protected] [email protected]
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