1. Smart Materials in Renewable Devices
Dr. Pramod K Singh
Sharda University, G. Noida, India
E mail:

2. Syllabus Materials- Basic Concepts
7.01
SMDXXX.A
Unit A
Materials- Basic Concepts
7.02
SMDXXX.A1
Unit A Topic 1
Classification of Materials, Bonding in solids
7.03
SMDXXX.A2
Unit A Topic 2
Crystal structure, Bravais lattice, Miller Indices
7.04
SMDXXX.A3
Unit A Topic 3
Imperfections of crystals
7.05
SMDXXX.B
Unit B
Dielectrics, Superconductors and Magnetic Materials
7.06
SMDXXX.B1
Unit B Topic 1
Dielectic materials and their properties
7.07
SMDXXX.B2
Unit B Topic 2
Superconductors and their applications
7.08
SMDXXX.B3
Unit B Topic 3
Magnetic materials and their properties

3. Syllabus Composite & Nanocomposite materials
7.09
SMDXXX.C
Unit C
Composite & Nanocomposite materials
7.10
SMDXXX.C1
Unit C Topic 1
Introduction of composite and Nanocomposite materials
7.11
SMDXXX.C2
Unit C Topic 2
Metal-Ceramic nanocomposite / Nanobiocomposites
7.12
SMDXXX.C3
Unit C Topic 3
Polymer based nanocomposites
7.13
SMDXXX.D
Unit D
Characterization Techniques
7.14
SMDXXX.D1
Unit D Topic 1
X-ray diffraction
7.15
SMDXXX.D2
Unit D Topic 2
UV-Visible spectroscopy
7.16
SMDXXX.D3
Unit D Topic 3
Infrared spectroscopy
7.17
SMDXXX.E
Unit E
Devices
7.18
SMDXXX.E1
Unit E Topic 1
Devices for energy conversion
7.19
SMDXXX.E2
Unit E Topic 2
Storage Devices
7.20
NSTXXX.E3
Unit E Topic 3
Sensors and Microelectronic devices

4. Marks Distribution
Assignment
Test
Presentation
Project/Att.

5. Application: Super Capacitors/DSSC

6. Materials Introduction
Principle, construction and working of Ultracapacitor
Advantage, disadvantage and application

7. Super Capacitor
Capacitor is a device to store the charge in an electric circuit.
Capacitor is made up of two conductors separated by an insulator called dielectric.
The dielectric can be made of paper, plastic, mica, ceramic, glass, a vacuum or nearly any other nonconductive material.
Some Capacitors are called Electrolytic in which the dielectric is aluminium foil conductor coated with oxide layer.

8. Ultracapacitor
The electron storing capacity of capacitor is measured in Farads
1 farad is approximately the charge with 6,280,000,000,000,000,000 electrons.
Definition:Ultracapacitors can be defined as a energy storage device that stores energy electrostatically by polarising an electrolytic solution.

9. Super Capacitor/Ultra Capacitor
Unlike batteries no chemical reaction takes place when energy is being stored or discharged and so ultracapacitors can go through hundreds of thousands of charging cycles with no degredation.
Ultracapacitors are also known as Double-layer capacitors/ Supercapacitors.

10. Principle, construction and working
Energy is stored in ultracapacitor by polarizing the electrolytic solution. The charges are separated via electrode –electrolyte interface.
Current Collector
Electrolyte
Separator +

11. Supercapacitor
Construction
Ultracapacitor consist of a porous electrode, electrolyte and a current collector (metal plates).
There is a membrane, which separates, positive and negative plated is called separator.
The following diagram shows the ultracapacitor module by arranging the individual cell C1 C2 C3 C4 C5
Ultracapacitor stack + --

12. Super Capacitor; Working Principle
There are two carbon sheet separated by separator.
The geometrical size of carbon sheet is taken in such a way that they have a very high surface area.
The highly porous carbon can store more energy than any other electrolytic capacitor.
When the voltage is applied to positive plate, it attracts negative ions from electrolyte.
When the voltage is applied to negative plate, it attracts positive ions from electrolyte.

13. ULTRA CAPACITOR

14. ULTRA CAPACITOR
Therefore, there is a formation of a layer of ions on the both side of plate. This is called ‘Double layer’ formation.
For this reason, the ultracapacitor can also be called Double layer capacitor.
The ions are then stored near the surface of carbon.
The distance between the plates is in the order of angstroms.
According to the formula for the capacitance,
Dielectric constant of medium X area of the plate
Capacitance =
Distance between the plates

15. ULTRA CAPACITOR
Ultracapacitor stores energy via electrostatic charges on opposite surfaces of the electric double layer.
The purpose of having separator is to prevent the charges moving across the electrodes.
The amount of energy stored is very large as compared to a standard capacitor
because of the enormous surface area created by the (typically) porous carbon electrodes &the small charge separation (10 A0 ) created by dielectric separator

16. ------------------------
Diagram shows the formation of double layer + 
Electrolyte
Separator
Electric double layer ▬

17. Super Capacitor: Advantage
Long life: It works for large number of cycle without wear and aging.
Rapid charging: it takes a second to charge completely
Low cost: it is less expensive as compared to electrochemical battery.
High power storage: It stores huge amount of energy in a small volume.
Faster release: Release the energy much faster than battery.

18. Super Capacitor: Disadvantage
They have Low energy density
Individual cell shows low voltage
Not all the energy can be utilized during discharge
They have high self-discharge as compared to battery.
Voltage balancing is required when more than three
capacitors are connected in series.

19. Super Capacitor: Applications
They are used in electronic applications such as cellular electronics, power conditioning, uninterruptible power supplies (UPS),
They used in industrial lasers, medical equipment.
They are used in electric vehicle and for load leveling to extend the life of batteries.
They are used in wireless communication system for uninterrupted service.
There are used in VCRs, CD players, electronic toys, security systems, computers, scanners, smoke detectors, microwaves and coffee makers.

20. Solid State Solar Cell (SSSC)
* Different conduction mechanism
* Charge separation
☞ to form M-S (Schottky) junctions
Advantage
High efficiency (~24 %)
Disadvantage
High cost
both type of semiconductors are prepared from highly pure semiconductor
by a severely controlled doping process

21. Classification & Principle
Si: mono, poly and amorphous-crystalline
Inorganic Solar Cell
GaAs, InP, CdTe
GaAs/Ge
Organic Solar Cell
Dye Sensitized Solar Cell
Conducting polymer - fullerene
Conducting polymer - conducting polymer
Organic polymer - nanoinorganic materials
☞Basic Principle
charge separation at the junction (interface) of two materials of different conduction mechanism

22. Components of DSSC TiO2 electrode with Dye
Electrolyte with redox couple
Counter electrode I-
I3-
External Circuit -
TCO conducting glass
Crystalline TiO2
Sensitizer dye
Polymer electrolyte

23. Dye-Sensitized Solar Cells
TCO Glass)
Electrolyte
Cathode( TCO Glass） e-
I-/I3- e-
(Semiconductor)
Anode
(Electrolyte)
(Dye)
TiO2
Low Cost
Good Recyclability
Wide Variation
High Energy Conversion Efficiency
Promising Candidate for Next Generation Solar cell !?

24. Role of redox couple in DSSC
* boys as electron
* filled boat as iodide
* empty boat as triiodide
Nam- Gyu Park and K. Kim, Phys. Stat. Sol. (a), 205 (2008) 1895

25. DSSC: Electrolyte Electrolyte in DSSC Polymer Electrolytes
re-reduction of the oxidized dye
transferring ion
oxidized by contact with electrode
Electrolyte in DSSC
Liquid Electrolytes Ion Conducting Gels
leakage
evaporation of the solvent
volatile liquid encapsulated
in the gel pores
leakage
evaporation of the solvent
Alternative
Polymer Electrolytes

26. Preparation of Polymer Electrolytes with IL
Mixed PEO, KI and I2 in acetonitrile to get PEO:KI/I2
polymer electrolyte
2. Added ionic liquid in the polymer electrolyte solution
3. Stirred continuously
4. Cast electrolyte solution in polypropylene dishes
5. Dried these films under vacuum to remove the traces of
solvent

27. Preparation of DSSC with Polymer Electrolytes/ IL
6. Prepared nanocrystalline TiO2 electrode by chemical
sintering method and sensitized (24 hrs.) into Dye
solution.
7. Casted polymer/IL solution (~400 μL)on TiO2 surface
followed two step cast method.
8. Sandwitched electrolyte solution between TiO2 and counter electrode.
9. Dried the cell under vacuum (~2 days) to remove the traces of solvent.

28. Fabrication of DSSC with PE/IL as electrolyte
TiO2 electrode
FTO glass
2x1.5 cm2
Blocking layer coating
500 0C for 30 min in furnace
Cut
30x30 cm2 CE
Wash
Pt layer coating
400 0C for 30 min in furnace
Two Scotch tape
Thickness ~ 50 ㎛
Dye Sensitization
(~ 24 hrs]
Sintering in furnace
500 0C for 30 min
TiO2 paste using Doctor blade
TiO2 electrode
PE/IL casting (2 step)
TiO2 sensitized with dye
PE/IL solid electrolyte CE
TiO2 electrode with Dye

29. Characterizations SEM (for TiO2 surface and particle size) TEM XRD
Impedance spectroscopy (for σ)
DSC (for check crystallinity)
J-V Characteristics
(to see solar cell performance)

30. SEM Measurement mesoporous TiO2 layer (30 min. sintering at 5000 C)
cross sectional view
top view

31. TEM Measurement Scrapped TiO2 powder TEM: *TiO2 particle size ~ 25 nm
*Pore diameter ~10-15 nm
*Pore wall mostly crystalline
Pore

32. XRD Measurement ☞ S (Substrate FTO peaks) at
☞*A (Anatase TiO2 peaks) at
25.30, 38.60, 480, 53.90, 55.10
(101),(112),(200),(105),(211)
[JCPDS# ]
**Average size(TiO2) ~26 nm
(Scherrer Formula)
☞ S (Substrate FTO peaks) at
26.60, 33.90, 430, 51.70, 54.80
(110),(101),(210),(211),(220)
[JCPDS# ]

33. Polymer Electrolyte Film: Fabrication
PEO in Methanol
Added KI & I2
COMPLEXATION
Stirred 24 hrs. in a
Beaker at 50 0 C
Clear PEO:KI/I2
solution.
Thorough
Mixing
Ionic Liquid
Pour in Petridish
&
Solution casting
Dry Polymer Film

34. Conductivity Measurement
Impedance Spectroscopy (for σ)
σ = G X L / A
G: conductance of the sample
L: thickness of the sample
A: the area of the sample

35. Electrical Conductivity:PEO:KI/I2+EMImSCN
Composition
σ (S/cm)
PEO:KI/I2 (EO/K=17)
8.80 x 10-6
PEO:KI/I wt% IL
1.39 x 10-5
PEO:KI/I wt% IL
1.90 x 10-5
PEO:KI/I wt% IL
5.99 x 10-4
*PEO:KI/I wt% IL
7.62 x 10-4
* After that composition film was not stable

36. Electrical conductivity
PEO:KI/I2+EMImSCN (IL)
doping of IL increased σ
attained max. σ at 80 wt%
IL concentration
After 80 wt% IL concentration,
we could not get free standing
polymer electrolyte film

37. XRD complete complexation reduced in crystallinity
no additional peaks of KI in c

38. XRD: Effect of IL (PEO crystalline peaks 19o and 23.1o)
The Intensity of PEO crystalline peaks
decreased after adding KI and IL
► Incorporation of IL reduced crystallinity
► no new peaks appeared
in (PEO:KI/I2)+80 wt% IL

39. DSC : Crystallinity Crystallinity χ (%) = ∆Hf / ∆Hf0
∆Hf0 of 100 % crystalline PEO film
was assumed 188.1J/g.
[Polymer., 37, 5109 (1996)]
Composition
Tm (0C)
∆Hf (J/g)
χ (%)
a. PEO:KI/I2 (EO/K = 17)
60.34
86.38
45.94
b. PEO:KI/I wt% IL
51.71
29.06
15.45
c. PEO:KI/I wt% IL
45.00
16.18
8.60

40. J-V Characteristics Voc (V) FF (%) η (%)
(using stable polymer films as electrolytes)
Jsc
(mA/cm2)
Voc (V)
FF (%)
η (%) a
0.22
0.74
77.4
0.1 b
0.32
0.67
56.0 c
0.78
0.65
68.3
0.3 d
1.88
0.63
50.7
0.6
(PEO:KI/I2) + x wt% IL
(a) x = 0, (b) x = 20, (c) x = 60, (d) x = 80

41. Thank you