Conducting polymers have potential in flexible supercapacitors due to their redox properties. Polyaniline, polypyrrole and polythiophene are promising conducting polymers. Graphene composites with these polymers improve performance by preventing aggregation and enabling fast ion transport. Future work aims to develop ternary composites and asymmetric capacitors to further increase energy density without sacrificing power. Conducting polymers work best in asymmetric configurations using different polymers or a polymer-carbon composite to expand the operating voltage window.

1. CONDUCTING POLYMER BASED FLEXIBLE
SUPER CAPACITORS
JISHANA BASHEER
M.TECH IN POLYMER TECHNOLOGY
CUSAT

3. JOURNAL 1 JOURNAL 2

4. JOURNAL 3 JOURNAL 4

5. INTRODUCTION
A Supercapacitor (SC) is also called an Ultracapacitor.
Flexible supercapacitors are highly attractive for the large number of
emerging portable lightweight consumer devices.
The novelty of a flexible supercapacitor is the incorporation of flexible
electrode or substrate material to combine structural flexibility with the
inherently high power density of supercapacitors.

7. FLEXIBLE SUPERCAPACITORS
ELECTRICAL DOUBLE LAYER CAPACITORS
(EDLC)
Electrode material: Carbon nanomaterials
PSEUDOCAPACITORS
Electrode material: Transition metal
oxides/hydroxides and conducting polymers

8. Conducting polymers (CPs) have been
considered as the most promising materials
for flexible supercapacitors.
Reverse doping-dedoping behaviour of CPs
has been used for various smart
applications.
They can be synthesized either by oxidative
polymerisation or by electrochemical
polymerisation into different forms.

9. Polyaniline
Polypyrrole
Polythiophene and
its derivatives

10. FLEXIBLE
SUPERCAPACITORS
CP BASED
HYDROGELS
CP BASED FIBERSCP BASED FILMS

11. As per Journal 1 : Polyaniline is
deposited using a spray
technique onto a flexible current
collector for pseudocapacitor
applications.
The polyaniline is characterised
using FTIR, SEM, and optical
absorption studies.

12. Electronically conducting polymers such as polypyrrole, polyaniline,
polythiophene and PEDOT can store & release charges through redox
processes.
When oxidation occurs, ions from the electrolyte are transferred to
the polymer backbone & on reduction, they are released back into
solution.
Among the conducting polymers, polyaniline has attracted much
attention.

13. EXPERIMENTAL WORK
MATERIALS USED FOR ANILINE PREPARATION
Aniline
Ammonium
persulfate
HCl
NaOH
Camphor
sulphonic acid

14. POLYANILINE
PREPARATION
Aniline is added to HCl
&kept for 1h at room
temperature.
Ammonium persulfate
in 20mL of distilled
water is then added to
the suspension under
stirring.
The prepared mixture
is filtered & then
rinsed with distilled
water.
PANI is simultaneously
dedoped by 25mL of
NaOH at 900 C for 5h.
PANI is doped with
camphor sulphonic
acid (CSA) and then
dissolved in
chloroform

15. PREPEARATION
OF FLEXIBLE
PANI
ELECTRODE
A flexible plastic sheet is coated
with gold.
Camphor sulphonic acid doped
PANI dissolved in chloroform is
sprayed on the active area.
The samples are left in an oven at
700 C to dry for 12h.

16. Electrochemical measurements
are performed using two
electrodes measurements in an
electrochemical cell.
The electrochemical
performance is analyzed for
supercapacitor electrodes in a
two-electrode system via
cyclic voltammetry (CV) and
electrochemical impedance
spectroscopy (EIS) using a
Potentiostat.

17. CHARACTERISATION
UV – Visible
Thermo
spectrophoto
meter
Fourier
Transform
Infrared
spectrophoto
meter
XRD
Machine
Scanning
Electron
Microscope
Raman
Microcope

18. UV – VISIBLE SPECTRUM

19. FTIR SPECTRA

20. XRD PATTERN

21. RAMAN SPECTRUM

22. SEM IMAGES

23. CYCLIC VOLTAMMETRY

24. NYQUIST PLOT

25. CHARGE AND DISCHARGE CURVES

26. As per Journal 2 : Pseudocapacitors made from
conducting polymers, which store charge via rapid
reduction and oxidation reactions, are a particularly
promising candidate.
This perspective explores conductivity and charge
storage mechanisms in conducting polymers and
describes how synthetic strategies can affect these
properties.
Developed the chemical correlations that have been
shown to enhance the performance of pseudocapacitive
electrochemical capacitors fabricated from conducting
polymers.

27. The current commercial electrochemical capacitor is the electric
double-layer capacitor (EDLC) which store charge electrostatically,
similar to a traditional electrolytic capacitor.
Pseudocapacitors store charge through reduction and oxidation events
leading to a high energy density relative to EDLCs.
The goal of this work is to elucidate accessible chemistries that
effectively control pseudocapacitive behavior in conducting polymers
and therefore advance electrochemical energy storage technologies.

28. ENERGY STORAGE
ELECTROCHEMICAL CAPACITOR

29. To have both high conductivity and electrochemical
capacitance, it must possess charge carriers, charge mobility,
facile kinetics, and readily available solvated counterions.
Electron insertion into the conduction band via n-
doping and/or removing an electron from the valence
band via p-doping increase charge carrier
concentration.
CP + n Red → (C+)n CPn-+ n Red+
CP + n Ox → CPn+ (A-)n + n Ox-

30. When a polymer undergoes ionization, the equilibrium
geometry of the ionized state is lower than that of the
ground state.
This lattice deformation causes the HOMO energy to shift up
and the LUMO energy to shift down, creating new energy
bands in the band gap that are delocalized over the polymer
chain.
The more a polymer chain is ionized (“doped”), the more
these islands overlap and delocalize over the entire material.

33. It is important to
maximize the
voltage window of
the device, the
capacitance of each
electrode and
minimize the RESR of
the cell.
The maximum
power (P)
output is P =
V2/4RESR
The maximum
energy (U)
stored in an
electrochemica
l capacitor is, U
= ½ CV2

34. Potential diagrams of fully charged and discharged states of (a) Type I, (b) Type II,
(c) Type III and (d) Type IV electrochemical capacitor.

35. Asymmetric
pseudocapacitors
are poised as a
way to increase
energy density.
3-Electrode cyclic
voltammetry
measures the
properties of
individual
electrode
materials.
Thermodynamically,
given an inert
electrode in an
aqueous, pH-neutral
electrolyte, water
will be split into
oxygen at roughly 1
V vs Ag/AgCl and
hydrogen at −0.3 V
vs Ag/AgCl.

36. PANi is often
positively polarized
and PEDOT
negatively polarized
versus the reference
electrode Ag/AgCl.
Certain electrode
materials can
suppress hydrogen
or oxygen evolution
depending on the
polarizing reactions
at the material
surface.
The safe working
window for a
symmetric, aqueous
device is generally
limited to around
0.6 to 0.8 V for
maximum device
lifetime.

38. KINETICS
High conductivity in a conducting polymer and low internal cell resistance
are paramount to fast kinetics.
Too high of a packing density adversely limits electrolyte accessibility and
reduces capacitance.
Chain length has a tremendous impact on mobility.
Increasing the degree of crystallinity and chain alignment, and producing a
defect free, homogeneous long chain polymer results in superior
pseudocapacitance.

39. The crystal structures of doped and undoped PEDOT
illustrate the interrelation between chain alignment and
charge mobility.
Control of pore structure is a promising area of research
for inducing high surface area and inducing facile
kinetics.
Another versatile area for improving kinetics is self-doping
via layer-by-layer assembly of alternating poly(o-
methoxyaniline) and poly(3-thiophene acetic acid) films.

40. CYCLABILITY
There are
several causes
for low cycling
stability in
conducting
polymer
pseudocapacit
ors.
The
adherence of
a polymer to
a current
collector has
been shown
to greatly
affect cycling
stability.
The
electrolyte is
an important
factor in
cycling
stability.

42. Extended cyclability can also be imparted
by depositing a thin carbonaceous shell
onto the conducting polymer electrode.
This physical buffer suppresses structural
deformation during cycling and leads to
95% capacitance retention for PANi and
85% for PPy electrodes after 10 000 cycles.

43. MORPHOLOGY
Nanostructures enhance free volume, accessible surface area,
and redox chemistry by promoting ion sorption and desorption
at the electrode/electrolyte interface.
Well-ordered nanowires and nanotube array with uniform
structure, high porosity and large surface area improve
capacitance and enhance charge/discharge rates in
mesoporous electrodes due to rapid ion diffusion.

44. PPy nanowire arrays improve stability during
charging/discharging cycles and achieve up to 566 and 259 F/g
at 1.1 and 13.75 A/g, respectively.
Various sized interconnected porous networks also facilitate
ion accessibility into the matrix of the material.
Porosity is essential for solvent diffusion and has a large effect
on capacitance.

45. Ion accessibility is maximized using a highly porous,
amphiphilic and pH responsive α-cyclodextrin polyacrylamide
hydrogel.
Specific capacitances of the stretched (315 F/g), folded
(301F/g), and original states (304 F/g) are based on the dry
weight of active mass PANi and remain capacitive at a high
charging density of 8 A/g.

47. • Heating of an aqueous ferric chloride
droplet in the presence of monomer
vapors leads to polymerization.
• This process is concomitant with droplet
evaporation, reduction of ferric chloride
to ferrous chloride, and precipitation of
oxidant microcrystals.
• These oxidant crystallites direct structure
and result in PEDOT nanofibers with a
conductivity of 130 S/cm.
EVAPORATIVE
VAPOUR PHASE
POLYMERISATION
(EVPP)

48. SEM IMAGE OF EVPP-PEDOT; (inset) X - RAY
PHOTOELECTRON SPECTRUM OF EVPP-PEDOT

49. As per Journal 3 : Recent developments of
graphene-conducting polymer
nanocomposites are overviewed.
Material design, synthesis and applications in
flexible supercapacitors are highlighted.
Current challenges and future perspective are
briefly commented.

50. Electrochemical
capacitors could
play a crucial role
in the
development of
new Energy
Storage Systems
(ESSs).
Although SCs store
lower amount of
energy than
batteries, in most
cases, their energy
density is still much
higher than that of
conventional
capacitors.
SCs can be fully
charged or
discharged in
seconds, while
batteries take
much longer time
due to
electrochemical
kinetics through a
polarization
resistance.

51. RAGONE PLOT

52. WORKING AND PRINCIPLE
CONVENTIONAL CAPACITOR SYMMETRIC SUPERCAPACITOR

53. The overall specific
capacitance (CS) of
a SC can be
calculated: CS =
C1C2/(C1+C2)
Energy Density:
E = ½ CV2
Maximum Power:
Pmax = v2/4R

55. The double layer capacitance of an EDLC can be
expressed as: C = εrε0 A/D
Capacitance of a pseudocapacitor : C = ΔQ/ΔV
In conducting polymers based pseudocapacitors, the
charge/discharge processes are associated with the
doping/de-doping processes of conducting polymers.

56. Two important future
research directions:
Polymer/carbon
material/metal oxide
ternary composite
electrode and asymmetric
capacitors were indicated
and summarized.
Graphene is
considered as an
ideal candidate
material for EDLC.
These studies show that
there is a significant
synergistic effect
between graphene and
polyaniline

57. Graphene (Gr), a two-dimensional monolayer of sp2-
bonded carbon atoms, exhibits a range of remarkable
physical properties.
CPs hold promising characteristics for electrochemical
energy storage, however, their low stability under
charge/discharge conditions has limited practical
application.
Gr can affect the molecular conformation and orientation
of CP chains, leading to the positive synergistic effect on
their composites.

58. The integration of CP
with Gr prevents self-
aggregation or re-
stacking of graphene
nanosheets.
Other advantages such as high surface
area considerable structural diversity,
small size of particles and short
distance for ion transfer, structural
uniformity and controllable
morphology.

59. MATERIAL DESIGN, SYNTHESIS
METHOD AND PERFORMANCE
Several crucial aspects have to be considered in
the development of Gr/CP nanocomposites;
i) Appropriate methods of synthesis
ii) Surface compatibility of CP with Gr
iii) Controlling thickness and morphology of
the CP film
iv) Surface properties of the nanocomposite
material (e.g. surface roughness,
hydrophilicity.

60. Strategic
approaches for
preparation of
Gr/CP
nanocomposite;
Through
incorporation of
the CP between
the Gr sheets (2D
nanocomposites)
Employment of Gr
nanosheets as a matrix
for the synthesis of CP
or Gr/CP
nanostructures with
various morphology
(3D networked
materials)

61. SCHEMATIC COMPARISON OF MAIN
METHODS FOR CPs SYNTHESIS

62. SCHEMATIC ILLUSTRATION OF THE INTERFACES BETWEEN THE
GRAPHENE – POLYMER COMPOSITE AND ELECTROLYTE

64. SCHEMATIC REPRESENTATION AND SEM IMAGES OF Gr/CP
NANOCOMPOSITES SYNTHESISED BY INCORPORATION OF CP
BETWEEN rGO SHEETS

65. SCHEMATIC REPRESENTATION AND SEM IMAGES OF Gr/CP
NANOCOMPOSITES SYNTHESISED BY SYNTHESIS OF CP LAYER
ON THE 3D Gr SURFACE

66. SCHEMATIC REPRESENTATION AND SEM IMAGES OF Gr/CP
NANOCOMPOSITES SYNTHESISED BY FABRICATION OF 3D
CP NANOFEATURES ON Gr SURFACE

68. EXAMPLES OF GRAPHENE CONDUCTING POLYMER
COMPOSITES BASED FLEXIBLE AND BENDABLE SCs

69. POLYMER BASED CAPACITORS
As per Journal 4 : Two important future research
directions: polymer/carbon material/metal oxide
ternary composite electrode and asymmetric
capacitors were indicated and summarized.
Graphene is considered as an ideal candidate
material for electrochemical doublelayer
capacitor.

70. ASSYMMETRIC CAPACITOR
There are limited studies on the measurement of
complete cells constructed with conductive polymer as
the electrode and most of these studies focus on the
single electrode.
There are limited studies on the measurement of
complete cells constructed with conductive polymer as
the electrode.
Combined with the advantages of long period, fast
reversible ac negative electrode and high conductivity
ionic water electrolyte of large capacity Faraday
electrode.

72. CONDUCTIVE POLYMERS SUPERCAPACITOR
Type I : Completely identical p type doped conductive polymer.
Type II : Different kinds of p type doped conductive polymer.
Type III :One conductive polymer doped with n type and other
doped with p type.

73. CONCLUSION

75. Perspectives of the further development of Gr/CP
nanomaterials for the capacitive energy storage
purposes сan be related to two main directions.
The first one is concerned with the improvement of
intrinsic properties of Gr/CP nanomaterials.
Related to a variety of ways using complete Gr/CP-based
electrodes in SCs.

76. More recently, some cost-effective and template-free
methods for the scale-up or mass fabrication of 3D Gr
frameworks under mild conditions have been proposed.
A number of composites, fabricated by further
modification of the structures with CPs, have shown
promising performances.
These latest advances may open new ways to use Gr/CP
nanostructured composite materials for the
development of inexpensive and scalable capacitive
charge-storing devices.

77. A lot of research
work has been
done to improve
the energy density
of supercapacitors
without sacrificing
their high power
capacity.
Considering that conductive
polymers can only be
reversible at a very small
potential range, their best
applications require
asymmetric configurations,
such as types on different
select of conductive
polymers.
This concept
expands the
voltage of the
capacitor to
achieve higher
energy and power
densities.

78. REFERENCES
• Preparation and characterization of a pseudocapacitor electrode by
spraying a conducting polymer onto a flexible substrate - Shaker
A.Ebrahim, Mohamed E.Harb, Moataz M.Soliman Mazhar B.Tayel.
• Conducting Polymers for Pseudocapacitive Energy Storage - Aimee M.
Bryan, Luciano M. Santino, Yang Lu, Shinjita Acharya and Julio M.
D’Arcy.
• Graphene-Conducting Polymer Nanocomposites for Enhancing
Electrochemical Capacitive Energy Storage - Fei Shen, Dmitry
Pankratov, and Qijin Chi.
• Conducting Polymers in Supercapacitor Application - D Y Su, Z G Liu, L
Jiang, J Hao, Z J Zhang and, J Ma.

79. ANY QUESTIONS