chemical modifications of polymers for alternative energy … for... · 2014. 3. 24. · dye...

Progress in the Development of Polymeric Materials for Alternative Energy Devices

at PENTEC research group, KMUTT

Division of Materials Technology, School of Energy, Environment and Materials, King Mongkut’s University of Technology (KMUTT), Thonburi, Thailand

PCT-4 Conference, Bangkok (March 20th, 2014)

Assoc. Prof. Dr. Jatuphorn Wootthikanokkhan

Introduction to polymers for energy related applications

Polymers for DMFC fuel cells Sulfonated PVOH Sulfonated PEEK Sulfonated PS

Polymers for solar cells Composite gel electrolyte Donor-acceptor copolymers Fullerene functionalized polymers

Future work

Talk Outline

2

3

1. Developments of polymers for energy related applications ∗ Solar cell components ∗ Low temperature fuel cells

2. Developments of polymers for environment

∗ Biodegradable polymers ∗ Development of new polymers from non-food biomass derived chemicals

3. Work closely with industries

Scope of R&D work at PENTEC

4

Polymer electrolytes and membranes for dye sensitized solar cell, fuel cells and batteries

Semiconducting polymers for polymer solar cells and electrochromic glass

Polymer sealants, films, and binders for solar cells, chromic glass

Types of polymeric materials being developed for uses in energy related applications


Glass

ITO

Donor / Acceptor

Al

Light

PEDOT:PSS

Dye sensitized solar cell

Polymer solar cell

Direct Methanol Fuel cells

Inorganic solar cells (Si)


Examples of polymers used in various alternative energy devices

5

6




Future work

Talk Outline

Type Electrolyte Operating temp.

(°C)

Alkaline Potassium hydroxide and/or anion exchange polymeric membrane

50-90

Proton exchange membrane (PEM)

Polymeric materials 50-125

Direct methanol Polymeric materials 50-120

Phosphoric acid Phosphoric acid 190-210

Molten carbonate Lithium/potassium carbonate mixture

630-650

Solid oxide Stabilized zirconia 900-1000

Polymers for DMFC fuel cells

Types of fuel cell

7

DMFCs have higher energy density (than PEMFC) but exhibit shortcomings such as (a) slower oxidation kinetics than PEFC below 100 °C and

(b) significant permeation of the fuel from the anode to the cathode resulting in a drop in efficiency of fuel utilization upto 50%

(Solid State Ionics 125 (1999), pp. 431–437)


How does the DMFC work?

8

Vehicular mechanism Grottuss mechanism Surface mechanism

In case of the Grottuss mechanism, protons do not move freely in water, but form complexes with water molecules through hydrogen bonds, which allow protons to hop through water very efficiently. , (just as sandbags hop from person to person)

Proton conductive Resistance to methanol Hydrophilic

Thermal stability above 100 °C Resistance to chemicals Good mechanical properties Good process-ability e.g., by solvent

casting Inexpensive (compared with Nafion® ,

1200 U$/m2)

Polymers for DMFC fuel cells Proton conducting

mechanisms

General requirements of DMFC membrane

9

http://en.wikipedia.org/wiki/Image:Grt_sm.gif

1. Sulfonated PVA-clay nanocomposites

2. Sulfonated PEEK / PVDF blends

3. Sulfonated PS / PVDF blends with compatibilizer

Development of proton exchanges membranes for DMFC fuel cells


Case studies

10

Methanol permeability of PVA is relatively low as compared to that of Nafion

Proton conductivity of the PVA can be induced by carrying out a sulfonation, using various agents

Conductivity of the sulfonated polymer was obtained at the expense of its flexibility



Sulfonated PVA-casted films

Sulfonation of PVA

11

P. Duangkaew, J. Wootthikanokkhan, Journal of Applied Polymer Science, Vol. 109, 452–458 (2008)



CloisiteNa (2 % w/w) Cloisite30B (2 % w/w)

TEM images Structure-property relationships

12

13

C

O

O O

n

C

O

O O

nSO3H

H2SO4

Sulfonated PEEK

PEEK

Sulfonation of PEEK

PEEK is a high performance semi-crystalline thermoplastic.

The sulfonation of PEEK in concentrated sulfuric acid is the only known method

J. Wootthikanokkhan and N. Seeponkai, Journal of Applied Polymer Science, Vol. 102, 5941–5947 (2006)



Membranes Proton Conductivity (S/cm)

Methanol Permeability (cm2/sec)

PVDF n/a No methanol crossover

sPEEK/PVDF (10/90) n/a No methanol crossover

sPEEK/PVDF (30/70) n/a No methanol crossover

sPEEK/PVDF (50/50) 7.18 × 10-3 No methanol crossover

sPEEK/PVDF (70/30) 9.10 × 10-3 5.34 × 10-9

sPEEK/PVDF (90/10) 8.99 × 10-3 5.66 × 10-9

sPEEK 10.34 × 10-3 2.35 × 10-7

Nafion 115 10.50 × 10-3 3.39 × 10-7

J. Wootthikanokkhan and N. Seeponkai, Journal of Applied Polymer Science, Vol. 102, 5941–5947 (2006)



14

SC=S CH2 CH

CH2 CH

CH2 C

CH3

CH2 CH

N(C2H5)2

+

Pr opagation

(C=O)OCH3

SC=S

N(C2H5)2

SC=S

N(C2H5)2

CH2

CH2 C

CH3

(C=O)OCH3

CH2 C

CH3

(C=O)OCH3

PS-b-PMMA

CH2

CH2 C

CH3

CH2 CH

C

O

OCH3

(1) (2)

PS-b-PMMA were synthesized for uses as a compatibilizer for sPS/PVDF blend membranes


3. Sulfonated PS / PVDF blends Synthesis of PS-b-PMMA Sulfonation of PS

The reaction system is homogeneous

sPS/PVDF is an incompatible blend

15

Without block copolymer With block copolymer

SEM micrographs

AFM micrographs

J. Wootthikanokkhan, P. Piboonsatsanasakul, S. Thanawan, Journal of Applied Polymer Science, 107 issue 2 (2008)1325-1336.


3. Sulfonated PS / PVDF blends Morphology of sulfonated PS/PVDF blend membranes

16




Future work

Talk Outline

17

Polymer for solar cells

Classifications of solar cells

18

Solar cells

Technologies based on Si wafer

Thin film technologies

New emerging technologies

Monocrystaline

Polycrystaline

Amorphous Si

Compound semiconductor CIGS

Quantum dot

Dye sensitized solar cells

Hybrid (inorganic-organic)materials solar cells

Organic PV

19

Polymer for solar cells

http://en.wikipedia.org/wiki/File:PVeff(rev110408U).jpg

Research Challenges

To improve power conversion efficiency;

* Reduction of photon loss * Reduction of exciton loss

* Reduction of carrier loss

* Minimize fullerene aggregation Research problems

Efficiency enhancement

Cost reduction

Stability

To improve stability and durability of the cells;

* Use inorganic or hybrid materials

* Encapsulate with polymer film

Polymer solar cells

To reduce cost;

* Alternative photoactive materials are needed to be developed

20

OMe

O

S

C6H13

n

O

On

MEH-PPV

Fullerene [C60]

PCBM

Polymer solar cells

Photo-active materials Hetero-junction

P3HT

Electron donors Electron acceptors

21

Donor/Acceptor BHJ materials Efficiency (%) References

PTh/C60 0.09 [Fan et al., 2006]

P3HT/PCBM 4.6 [Gadisa et al., 2009]

P3PT/PCBM 4.3 [Gadisa et al., 2009]

P3BT/PCBM 3.2 [Gadisa et al., 2009]

P3HT/PCBM 2.0 [Sivula, 2006]

P3HT/PDI (perylene diimide) 0.3 [Rajaram, 2009]

P3HT/PCBM 0.45 [Vanlaeke, 2006]

P3HT/PCBM (after anealing) 2.7 [Vanlaeke, 2006]

N/A 10* Y.W.Su, Materials Today 2012, * Mitsubishi Chemicals

Polymer solar cells

Varieties of efficiency values

22

Absorption of photon by organic semi-conductor produce excited electron-hole pairs (Exciton)

Binding energy between electron-hole of organic material is relatively high (typically 1.0 eV) as compared to that of inorganic material (0.1 eV)

Diffusion length of photo-excited electron-hole pair (exciton) is relatively short (5-10 nm) as compared to the distance between electrode (film thickness)

The electron-hole pairs tend to recombined before traveling into the electrode.

This means that only small amount of the excitons are capable of spitting into free electron and hole

Polymer solar cells Exciton loss

23

Durability and lifetime of the DSSC cells, mainly due to liquid electrolyte leakage, have yet to be further improved

(Chung et al., Nature, 2012)

Corrosion of metal electrode due to the use of iodine redox couple

(Chen et al., 2010; Wang et al., 2011)

Challenges for the development of DSSC

Dye sensitized solar cells

Some strategies for improving durability of DSSC

Using a nonvolatile ionic liquid (such as immidazolium salts)

Applying one dimensional nanostructure of TiO2 (nanotubes, nanofibers) to overcome the “pore filling problem”

Using inorganic-organic hybrid (perovski compound and polymer) as light absorber and hole transporter

(Gratzel et al., Materials Today, 2013 and Heo et al., Nature Photonics, 2013)

Developing solid based electrolytes

Encapsulate the cell 24

Electrolytes Properties

Mechanical Thermal stability

Electro-chemical stability

Conductivity (S/cm)

Organic Liquid Low Low Moderate High (1×10-3 - 1×10-2 )

Room temp. ionic liquid Low High Low to

Moderate

Moderate to High

Solid polymer electrolyte High High High Very low (1×10-4 - 1×10-9)

Gel polymer electrolyte Moderate Moderate Moderate Moderate

Reproduced from Jung et al., Bull. Korean Chem Soc, 2009

Future trends : Development of nanocomposite gel polymer electrolyte

Polymer for solar cells Comparison of properties of various electrolytes

25

1. Preparation of composite gel polymer electrolyte based on La2O3 filled P(VDF-HFP) nanofibers

2. Synthesis of P3HT-b-PSFu and photovoltaic performance of P3HT/PCBM containing the copolymers

3. Synthesis of fullerene functionalized polymers for uses as an electron acceptor in BHJ solar cells Fullerene grafted PS Fullerene grafted DHPVC

Development of polymer for solar cells

Polymers for solar cells

Case studies

26

12 wt% 14 wt%

16 wt% 18 wt%

Porosity and electrolyte uptake of the nanofibers are greater than those of a solution casted P(VDF-HFP) film

Averaged diameter of electrospun P(VDF-HFP) nanofibers increased with polymer concentration

1. Preparation of Composite Gel Polymer Electrolyte based on La2O3 filled P(VDF-HFP) Nanofibers


Morphology and properties of electrospun PVDF-HFP nanofiber

0100200300400500600700

0 20 40 60 80Ele

ctro

lyte

upt

ake

(%)

Wetting time (min)

E-10 kV

E-12 kV

E-14 kV

E-16 kV

casting

0

20

40

60

80

100

E-10 kV E-12 kV E-14 kV E-16 kV casting

Poro

sity

(%)

SEM image of a casted film

27



Sample Electrolyte

uptake (%)

Relative

absorption ratio

∆HM

(J/g)

Ion conductivity

(S/cm) Casted P(VDF-HFP) film 102.89 0.84 62.29 6.04 x 10-4

Electrospun P(VDF-HFP)

(10 kV) 562.24 0.69 48.81 1.02x 10-3


(12 kV) 607.95 0.76 45.94 1.11 x 10-3


(14 kV) 572.59 0.83 52.68 1.22 x 10-3


(16 kV) 620.78 0.82 51.03 1.12 x 10-3

Electrospun PVDF-HFP nanofibers

28



Electrospun P(VDF-HFP)-La2O3 composite nanofibers

SEM image (SE) EDX dot map

0.00.10.20.30.40.50.60.7

0 2 4 6 8 10 Ave

rage

fibe

r di

amet

er (𝜇m

)

La2O3 content (%) 29

Sample ∆HM

(J/g)

Ion conductivity

(S/cm)

P(VDF-HFP) 52.68 1.22x 10-3

P(VDF-HFP) + 2%La2O3 44.29 1.20x 10-3

P(VDF-HFP) + 4%La2O3 44.02 1.32x 10-3

P(VDF-HFP) + 6%La2O3 45.97 1.12x 10-3

P(VDF-HFP) + 8%La2O3 43.05 1.30x 10-3

P(VDF-HFP) + 10%La2O3 43.74 1.43x 10-3

N.Rattanathamwat, J. Wootthikanokkhan, N. Nimitsiriwat, C. Achayanont, U. Asawapirom, and A. Keawprajak , International Journal of Polymeric Materials, 63(2014)448-455

Polymers for solar cells 2. Synthesis of P3HT-b-PSFu and photovoltaic performance of P3HT/PCBM containing the copolymers

Polymers solar cells

30

P3HT/PCBM

S

Hex

OCH3

O

n x y

P3HT-b-PSFu

OMe

o

PCBM

S n

P3HT

P3HT P3HT-b-PSFu

PCBM

3.1 eV

5.1 eV

4.2 eV

6.0 eV

3.3 eV

4.8 eV

4.3 eV

4.7 eV

e-

e- e-

h+ h+

h+

Al

ITO

AFM micrographs (topographic image) of P3HT/PCBM containing different type

of donor-acceptor block copolymers

Energy levels of P3HT, PCBM and P3HT-b-PSFu

Polymers for solar cells 2. Synthesis of P3HT-b-PSFu and photovoltaic performance of P3HT/PCBM containing the copolymers


N.Rattanathamwat, J. Wootthikanokkhan, N. Nimitsiriwat, C. Achayanont, U. Asawapirom, and A. Keawprajak , International Journal of Polymeric Materials, 63(2014)448-455 31

CH2 CH CH2 CH S C

S

N

C2H5

C2H5

CH2Cl

CHH2C CH

CH2Cl

H2C

S C

S

N

C2H5

C2H5

C

S

N

C2H5

C2H5

TD

CH2 CH CH2 CH S C

S

N

C2H5

C2H5

H2C

fullerene

x y

++

UV 4 h.Styrene

x y

PSFu

ATRA80 C, 3 h.

Chloromethyl styrene

PS-PCMS

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0 10 20 30 40 50 60 70 80 90 100Acceptor material content (pph)

Eff

icie

ncy*

10-2

(%

)

C60

PSFu 3

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0 20 40 60 80 100

Acceptor material content (pph)

Effic

iency

*10-2

(%)

PSFu 3 C60

rd-P3HT

rr-P3HT


3.1 Synthesis of fullerene grafted polystyrene [PSFu]

Effects of acceptor type and content on PCE

32

THF/toluene mixture, which is a good co-solvent for rd-P3HT, also favors the solubility of PSFu

Dichlorobenzene which is a good solvent of rr-P3HT also promotes a better solubility and prolongs some aggregation of the C60


3.1 Synthesis of fullerene grafted polystyrene [PSFu]

Optical micrographs of various P3HT/acceptor blend films

20 pph C60 60 pph C60

20 pph PSFu 60 pph PSFu (a) (b) (c)

(d) (e) (f)

20 µm

rd-P3HT rr-P3HT

33

2 different techniques can be used;

1. Atom transfer radical addition

2. AIBN based fullerenation


Preparation of fullerene grafted PVC and fulllerene grafted DHPVC

34

3.2 Fullerene functionalized dehydrochlorinated PVC

35


3.2 Fullerene functionalized dehydrochlorinated PVC

-10

-5

0

5

10

15

20

25

30

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

J (m

A/cm

2)

Voltage (V)

PCBM (Left) 1sttest

DHN05 90-10(Left) 2nd test

DHN05 95-5(Left) 1st test

PVCN5 90-10(Left) 2nd test

PVCN5 95-05(Left) 2nd test

Acceptor materials *

Power Conversion Efficiency (%)

PCBM 0.51

Fullerene (C60) 0.16

C60-g-DHPVC 0.01

PCBM /C60-g-DHPVC (95/5) 0.26

PCBM /C60-g- DHPVC (90/10) 0.48

PCBM /C60 –g- DHPVC (80/20) 0.71

PCBM /C60 –g- DHPVC (70/30) 1.34

PCBM /C60 –g- DHPVC (60/40) 0.66

PCBM /C60 –g- DHPVC (50/50) 0.70

Table II Power conversion efficiency of bulk heterojunction polymer solar cells containing different types of electron acceptor phase * P3HT/acceptor = 100/60 % w/w




Future work

Talk Outline

36

Types of energy devices

Research problems/ Challenges

Materials to be developed

Polymer solar cell (PSC)

Alternative photoactive materials (electron acceptors) for BHJ

Electrospun nanofibers based on C60-g-DHPVC/PCBM

Fullerene grafted graphene

Dye sensitized solar cell (DSSC)

Avoiding corrosion Iodine free electrolytes

(Flexible) PSC & DSSC Durability enhancement New encapsulants and sealing films

Future work

Examples of our future work

37

Fundamental knowledge in polymer science can contribute

significantly to the progress and developments of energy

technology.

There are plenty of research problems and opportunities to

continue working on. These include the developments of new

materials (organic, inorganic and hybrid) for enhancing efficiency

and durability of the energy cells.

38

Concluding Remarks

∗ The Nanotechnology Center (NANOTEC), Ministry of Science and Technology, Thailand, through its program of Center of Excellence Network.

∗ Thailand Research Fund (TRF) and the Commission on Higher Education, the Ministry of Education for providing research grant. (Grant code: RMU 5180049)

∗ Dr. Chanchana Thanachayanont (MTEC)

∗ Dr. Udom Assawapirom (Nanotec)

∗ Mr. Anusit Keawprajak (Nanotec)

∗ Dr. Sombat Thanawan (Mahidol University)

∗ Ms. Narumon Seeponkai (Ph.D student)

∗ Ms. Noparat Keaitsirisart. (M.Eng. Student)

Acknowledgements

39

Thank You for Your Attention Questions & comments are welcome

iThedooktm Photographer: http://ithedook.multiply.com

Progress in the Development of Polymeric Materials for Alternative Energy Devices at PENTEC research group, KMUTT

chemical modifications of polymers for alternative energy … for... · 2014. 3. 24. · dye...

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