new generation ion conducting polymer electrolytes for electrochemical energy technologies maria...
TRANSCRIPT
New generation ion conducting polymer electrolytes for
electrochemical energy technologies
Maria Luisa Di Vona
R. Narducci, L. Pasquini
PhD of Industrial EngineeringResearch Activity on Energy
17th October 201417th October 2014
Systems based on Polymer Electrolyte Membranes (PEM)
2H+ +2e- → H2
cathodic process:
H2O
H2O + O2 H2 (+ H2O)
PEManode cathode
( H2O )
H+
H+
electrocatalyst layers
H2O → 1/2O2 + 2e- + 2H+
anodic process:
AEM-FC
PEM-FC
Redox flow batteries
Electrolysers
PhD of Industrial EngineeringResearch Activity on Energy
Anion Exchange Membranes
Cationic Exchange Membranes
O
O
CH3CH3
S
OO
N+
N+
Methylen ammonium Aromatic Polymers
Polymer electrolyte membranes (PEM)
fluorine
x yCF CF2
OCF2CF
CF3
O(CF2)2SO3H
CF2CF2
X = 6 - 10; y = z = 1
z
Nafion
PhD of Industrial EngineeringResearch Activity on Energy
4
Amphoteric Exchange Membranes
O
O
CH3 CH3
S
OO
OHH N+
R
RR
SO
O OH
HO-
PhD of Industrial EngineeringResearch Activity on Energy
A fuel cell consists of two bipolar graphite plates that hold a Membrane Electrode Assembly (MEA). Each MEA is a set of two electrodes sandwiched around a Polymer Electrolyte Membrane (PEM) .
High conductivityHigh conductivity
Chemical and thermal stabilityChemical and thermal stabilityLow costLow cost
Long lifeLong life
Low permeability to reactantsLow permeability to reactants
Controlled water absorption Controlled water absorption Mechanical strengthMechanical strength
Ideal Membranes
0
20
40
60
80
100
0 5 10 15
l
sm
ax/M
Pa
E. Sgreccia M. Khadhraoui, M.L. Di Vona Journal of Power Sources 178 (2008) 667–670
Reproduced from Introduction To Polymers R.J. Young and PA. Lovell. CRC Press 1991
PhD of Industrial EngineeringResearch Activity on Energy
Relations between membrane stiffness, hydration, morphology and conductivity
Possible solutions for improving membrane performances
….
Cross-linking
Composite
SiO2, TiO2, ZrO2….
Inorganic proton conductorsZirconium phosphates, heteropolyacids..
Oxides
Thermal treatments
Modification of the polymeric backbone
Functionalization
Polymer blends
Block copolymers
PhD of Industrial EngineeringResearch Activity on Energy
O
C
O
SO2
OSi(OH)3
O
C
O
O
O
C
O
O
SO3H
0.4
O
C
O
O
SO3H
Si(OH)3
0.2
0.4
H3O+
(OH-)
Fuel Cell Membrane
Hybrid Polymer Blends(SPEEK + SiPPSU)
Inorganic-Organic Nanocomposites
(F-TiO2)
(Cross-Linking)
Hybrid Organic-Inorganic Polymers(SOSiPEEK)
Composite MaterialsModified Polymers
BlendsThermal Treatments
FCH-JU LoLiPEM Project
www.lolipem.eu
Strategies for improving Polymer Electrolyte Membranes
Patent DE 10 2009 006 493A1Patent DE 10 2009 006 493A1
Chemical cross-link
Van der Waals interactions
Covalent bondsIonic bonds
Strategies for improving Polymer Electrolyte Membranes
PhD of Industrial EngineeringResearch Activity on Energy
Knauth P, Di Vona ML. Solid State Ionics, 2012, 225, 255-259Knauth P, Di Vona ML. Solid State Ionics, 2012, 225, 255-259
2 H2 + O2 = 2 H2OHigh efficiency (up to 60%?)
« Zero emission »!
Proton Exchange Membranes
DMSO,
Cross-linking of SPEEK by thermal treatments
PhD of Industrial EngineeringResearch Activity on Energy
80- 100 °C; RH 70-100%80- 100 °C; RH 70-100%
XL- induced properties:
low solubility in solvents
low fuel permeability
high dimensional stability
enhancement of tensile strength
reduction of ductility
decrease of free volume
enhancement of glass transition temperature
Cross-linked (XL) aromatic polymers
H. Hou, M. L. Di Vona, P. Knauth Durability of Sulfonated Aromatic Polymers for Proton-Exchange-Membrane Fuel Cells ChemSusChem 2011, 4, 1526
H. Hou, M. L. Di Vona, P. Knauth Building bridges: Crosslinking of sulfonated aromatic polymers-A review. Journal of Membrane Science 2012, 423, 113
0
20
40
60
80
100
120
140
0 10 20 30 40 50 60 70 80 90 100
l
T/°
C
4 SPEEK(0.9) 160 (DMSO)
1 SPEEK(0.6) 120+160 (DMSO)
2 SPEEK(0.6) 160 (DMSO)
3 SPEEK(0.9) 120+160 (DMSO)
5 SPEEK(0.6) 120 (DMSO)
6 SPEEK(0.6) 120 + 160 (DMAc)
12
3
4
5
6
7 SPEEK(0.9) 120 (DMSO)
7
soluble soluble
soluble
soluble
soluble
soluble
Cross-link
No cross-link
SPEEK solvent
annealing
Cross-linking of SPEEK by thermal treatments
Di Vona ML, Pasquini L, Narducci R, Pelzer K, Donnadio A, Casciola M, Knauth P. Journal of Power Sources, 2013, 243, 488-493; Di Vona ML, Sgreccia E, Muthusamy T, Khadhraoui M,
Chassigneux C, Knauth P. Journal of Membrane Science, 2010, 354, 134-141
Di Vona ML, Pasquini L, Narducci R, Pelzer K, Donnadio A, Casciola M, Knauth P. Journal of Power Sources, 2013, 243, 488-493; Di Vona ML, Sgreccia E, Muthusamy T, Khadhraoui M,
Chassigneux C, Knauth P. Journal of Membrane Science, 2010, 354, 134-141
How does the cross-link (XL) reaction occur ?
O
O
C
O
O
C
O
O
O
SO3H
C
O
O
OSO2+
Yx
+
O
O
C
O
SO3H
SO2
O
O
O
C
O
SO2
O
O
O
O
SO3H
SO2
O
O
O
O
C
O
O
SO2
O
O
a
bb
bc
a
b
c
Covalent cross-linking during heat treatmentsof SPEEK membranes at T ≥ 140 °C occurs in presence of small quantities of DMSO. Electrophilic aromatic substitution by sulphonium ions (-SO2
+)in activated positions occurs preferentially.
Mechanical properties: traction experiment
0
500
1000
1500
2000
0 0,1 0,2 0,3 0,4 0,5 0,6DXL
E/M
Pa
Dry
Stiffness explores essentially weak bonds (low displacements): Van der Waals bonds; Defects, such as entanglements; Presence of water (distance between chains)
H2O and DMSO: high dielectric constant solventsReduce ionic bond strengthReduction of stiffness and strength
Influence of Water:Influence of Water:
Dynamic Mechanical Analysis
E. Sgreccia, J.-F. Chailan, M. Khadhraoui, M. L. Di Vona, P. Knauth Journal of Power Sources 195 (2010) 7770–7775
60 80 100 120 140 160 180 200 220 2401
10
100
1000
10000
1
E' /
MP
a
T / °C
1 S-PEEK(0,9) DMSO untreated2 S-PEEK(0,9) DMAc untreated3 S-PEEK(0,77) DMSO untreated4 S-PEEK(0,6) DMSO untreated5 S-PEEK(0,9) DMSO 140°C6 S-PEEK(0,9) DMSO 160°C7 S-PEEK(0,6) DMSO 160°C
2
34
56
7
No cross-link
Solid State Proton Conductors Eds. P. Knauth and ML Di Vona, 2012 WileyDi Vona ML, Alberti G, Sgreccia E, Casciola M, Knauth P. International J Hydrogen Energy, 2012,
37, 8672-8680
Cross-linkCross-link
Optimisation of proton conductivity: calculated and experimental data for SPEEK
17
Conductivity maximum at l
At 100 °C, sS/cm forl
This plot allows determining: the maximum achievable conductivitythe conductivity for a certain hydration
Knauth P, Pasquini L, Maranesi B, Pelzer K, Polini R, Di Vona ML Fuel Cells,13, 79 (2013)
100 °C
25 °C
Hydration of XL-SAP at high a(H2O) and high T! Only XL membranes can do this! Hydration of XL-SAP at high a(H2O) and high T! Only XL membranes can do this!
SPEEK GF l (25°C) s (S/cm)
Swelled 100°C 54 25°C=5,8 10∙ -2
40°C=6,5 10∙ -2
60°C=7,3 10∙ -2
80°C=7,9 10∙ -2
Swelled 110°C 73 25°C=9,3 10∙ -2
40°C=1,1 10∙ -1
60°C=1,3 10∙ -1
80°C=1,4 10∙ -1
“Memory Effect”
Polarization results for MEAs based on cross-linked SPEEK membranes (EX-330) and a Nafion212 membrane (triangles).
Polarization results for MEAs based on cross-linked SPEEK membranes (EX-330) and a Nafion212 membrane (triangles).
Excellent fuel cell characteristics for XL-SPEEK
G. Barbieri, M. L. Di Vona, P. Knauth, R. Hempelmann, L. D. Beretta, B. Bauer, M. Schuster, L. F. Vega Journal of Power Sources, submitted
LoLiPEM ProjectLoLiPEM Project
Anion Exchange Membranes
R R
N+ N
+
R
RR
R
RR
OH-
OH-
1/2 O2 +H2O + 2e
2OH-
2OH- +
H2
2H2O
+ 2e
OH -O2 + H2OH2
-H2O
H2 + 2OH- 2H2O + 2e
½ O2 + H2O + 2e 2OH-
H2 +1/2O2 H2O
Ec = 0.39 V
(pH = 14)
Ea = -0.84 V
Use of non-noble metalsUse of non-noble metals Low stability Low stability Low ionic conductivity Low ionic conductivity
AEM-FC 60°C, RH 100%60°C, RH 100%
H
HR N+
H H
RR
OH-
NR
R CH2
R+
N+
R
R
R
R
H
Hofmann elimination
Stability of cationic groups
E2: antiperiplanar mechanism
Is it possible to prevent E2 reactions?
YES
N+R
R
R
N+
RR
R1
R1
R1
R, R' bulky groups
N RR
ROH
-
OH +
NR
RR OH+
SN2 reactionStability of cationic groups
or………..
Is it
pos
sible
to
prev
ent S
N2
reac
tions
?
Maybe
1,4-diazabicyclo[2.2.2]octane (DABCO)
1,5-Diazabicyclo[4.3.0]non-5-ene (DBN)
N+
N
N
N+
positive charge delocalized by resonance in the system
Stability of cationic groups
positive charge delocalized by long range interaction
AM-PSU
Stability of backbones
O
O
CH3CH3
SO O
N+
HO-
Is it
pos
sible
to
prev
ent
degr
adat
ion
reac
tions
?
Two strategies:
Polymer cross-linking
Delocalization of the positive charge
N+
N
N
N+
Maybe
Di Vona, M. L. Narducci, R. Pasquini, L. Pelzer, K Knauth, P.INTERNATIONAL J HYDROGEN ENERGY 39, 14039-14049, 2014
Di Vona, M. L. Narducci, R. Pasquini, L. Pelzer, K Knauth, P.INTERNATIONAL J HYDROGEN ENERGY 39, 14039-14049, 2014
Mechanical properties of PSU-TMA membraneMechanical properties of PSU-TMA membrane
Typical tensile stress-strain curves of rigid TMA–PSU derivatives in hydroxide form (black: DAM = 0.39, red: DAM = 0.93) obtained at 25°C and ambient humidity
DAM/% 39 93
E/MPa 980±70 840±90
σMAX/MPa 28±6 27±1
ε@ break/% 5±2 5±1
E: elastic modulus
σMAX: tensile strength
ε @ break : elongation at break
Sample IEC WU (%)s (mS/cm)
in H2O
s (mS/cm) in H2Oafter treatment
in KOH 2M (60°C, 168h)
TMA 0.81 19 2.2 -TMA 1.34 40 4.6 -
TMA 1.64 53 12 -
DABCO 1.10 33 5.3 -DABCO 1.70 504 6.7 -
DBN 0.91 35 0.2 0.2XL(5%)-
TMA120°C 24h
0.81 17 1.0 -
XL(5%)-TMA
120°C 24h1.19 32 2.2 -
XL(5%)DBN
120°C 24h0.91 34 0.2 0.2
O
O
CH3CH3
SO O
N+
HO-
conductivity in Hconductivity in H22OO
Manning condensation?
Redox flow batteries
Stationary electricity storage (“Smart grid”)
Redox flow battery is a rechargeable battery where rechargeability is provided by two chemical components dissolved in liquids contained within the system and separated by a membrane
Redox flow battery is a rechargeable battery where rechargeability is provided by two chemical components dissolved in liquids contained within the system and separated by a membrane
Anion-Conducting Sulfamminated Aromatic Polymers by Acid Functionalization
Cl- Br- NO3- HSO4
- H2PO4- CH3CO2
-
O
O
O
SO O
NH+CH3
CH3
SA-PEEK
Anion Exchange Membranes
L. Pasquini, P. Knauth, K. Pelzer, M. L. Di Vona, Solid State Ionics, SubmittedL. Pasquini, P. Knauth, K. Pelzer, M. L. Di Vona, Solid State Ionics, Submitted
Conductivity properties in water at 25 °C.
0.00E+005.00E-041.00E-031.50E-032.00E-032.50E-033.00E-033.50E-034.00E-034.50E-03
HClHBr
H2SO4
HNO3
H3PO4
CH3CO
OH
Diethyl
Dimethyl
The conductivity is stable after 1 week
0.05.0
10.015.020.025.030.035.040.045.0
Diethyl
Dimethyl Water uptake at 25 °C
The anion conductivity occurs in a range of low pH values
Applications are interesting in all vanadium redox flow battery (high concentration of sulfuric acid; the hydrogen sulfate anion is the major charge carrier)
.
B Schwenzer et al. ChemSusChem 2011, 4, 1388
A higher ionic conductivity is expected due to
the contribution of both hydrogen sulfate anions
and protons
Mechanical properties
high tensile strength (1460 MPa)
high elastic modulus (53 MPa)
low elongation at break (6 %)
High rigidity polymers potentially useful for separation membranes
The vanadium permeability measured with dimethyl- and diethylamine sulfamminated polymers is 1.3x10-9 and 5x10-10 cm2/min, respectively. These values are 3 orders of magnitude lower than those of Nafion measured under similar conditions (1.4x10-6 cm2/min).
The vanadium permeability measured with dimethyl- and diethylamine sulfamminated polymers is 1.3x10-9 and 5x10-10 cm2/min, respectively. These values are 3 orders of magnitude lower than those of Nafion measured under similar conditions (1.4x10-6 cm2/min).
PermeabilityPermeability
Micro-scale energy storage and conversion
Micro-scale energy storage and conversion
Riccardo PoliniLuciana LuchettiEmanuela Sgreccia Tamilvanan Muthusamy Riccardo NarducciLuca Pasquini
@
Italian Ministry for University and Research
Franco-Italian University (Vinci project) Thesis E. SgrecciaCap III: R. Narducci, L. Pasquini
Acknowledgments
@Giulio AlbertiMario CasciolaAnna Donnadio
Dr. Jedeok Kim NIMS (Japan)
Prof. E. Smotkin Northeastern University, Usa
Dr. Jedeok Kim NIMS (Japan)
Prof. E. Smotkin Northeastern University, Usa
@
Financial support:
EU Fuel Cells and Hydrogen Joint Undertaking
Acknowledgments
www.lolipem.eu
ITM-CNR (G. Barbieri)
Edison (D. Beretta)
MatGas (L. Vega)
UMarseille (P. Knauth)
USaar (R. Hempelmann)
Fumatech (M. Schuster) CUT (B. Grochola)
URoma2 (ML Di Vona)
Hybrid systems:Synergic effect between Organic and Inorganic phases not
achievable by physical mixing
Covalent or iono-covalent or Lewis
acid-base bonds
Class II
No covalent or iono-covalent bonds
Class I
Strategies to Form Hybrid Membranes
Class II hybrids: Silylate-polymers
Strain
Blends:
Silicon enhances membrane strength!
Soft materials
E. Sgreccia et al., Journal of Power Sources, 178, 667 (2008)
S-PPSU 7%
SiS-PPSU 7%
Si-PPSU 7%
E [MPa] s max [MPa]400±
100
10±3 8±1
1200±300
26±4 4±1
1500±100
41±2 4±1
max [%]
Sulfonation reduces membrane strength!
Mechanical properties: Tensile stress
Phenyl-silanol group
O
O
SO O
Si(OH)2
SO3H
SO3H
S
O
OO O
SO3H
SO3H0.95
0.05
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
OO
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
O
SO3H
O
C
O
Si-PPSU: calculated conformation
limited chain mobility leads to a strong increase of Tg with respect to pure SPEEK
s (S
cm-1) SPEEK
SPEEK/Si-PPSU
y = 2E-05e0,0817x
y = 8E-06e0,0912x
0,0001
0,001
0,01
0,1
0 20 40 60 80 100
RH/%
Conductivity is measurable and continues to increase at high RH
Improvement in comparison to unmodified SPEEK, which swells!
T = 100°C
Conductivity properties