Research Article Performance of the Chemical and...

Research ArticlePerformance of the Chemical and Electrochemical Compositesof PPyCNT as Electrodes in Type I Supercapacitors

S C Canobre F F S Xavier W S Fagundes A C de Freitas and F A Amaral

Laboratorio de Armazenamento de Energia e Tratamento de Efluentes (LAETE) Instituto de QuımicaUniversidade Federal de Uberlandia (UFU) Avenida Joao Naves de Avila 2121 38408-100 Uberlandia MG Brazil

Correspondence should be addressed to S C Canobre scanobreiqufuufubr

Received 25 October 2014 Revised 27 December 2014 Accepted 30 December 2014

Academic Editor Yuhua Xue

Copyright copy 2015 S C Canobre et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Polypyrrole (PPy) is one of the most studied conducting polymers and a very promising material for various applicationssuch as lithium-ion secondary batteries light-emitting devices capacitors and supercapacitors owing to its many advantagesincluding good processability easy handling and high electronic conductivity In this work PPy films were chemically andelectrochemically synthesized both in and around carbon nanotubes (CNTs) The cyclic voltammograms of the device composedof the electrochemically synthesized PPyCNT composites as working and counter electrodes (Type I supercapacitor with p-typedoping) showed a predominantly capacitive profile with low impedance values and good electrochemical stability with the anodiccharge remaining almost constant (1138mC) a specific capacitance value of 530 F gminus1 after 50 charge and discharge cycles and acoulombic efficiency of 992The electrochemically synthesized PPyCNT composite exhibited better electrochemical propertiescompared to those obtained for the chemically synthesized compositeThus the electrochemically synthesized PPyCNT compositeis a promising material to be used as electrodes in Type I supercapacitors

1 Introduction

Polymers are macromolecules formed of small structuralunits (the monomers) The conducting polymeric materialshave gained attention in the last 50 years owing to easyprocessing and low costs when compared to metals like ironaluminum copper and others Recently new polymer classeshave been studied owing to their excellent conducting prop-erties They are known as ldquoconducting polymersrdquo and havemolecular bonds composed of conjugated double (C=CndashC) which result in an electronic delocalization along thepolymeric chain [1] Themost important characteristic of theelectrically conducting polymers is not just the intrinsic con-ductivity but the ability to reversibly change their oxidationand reduction states resulting in a wide range of electronicconductivity values that vary from low (fully reduced state)to high (partially oxidized state) [2]

Among the conducting polymers polypyrrole (PPy) hasattracted much attention in terms of its wide range ofapplications which are based on the reversibility betweenthe redox states [3] showing good conducting properties

and the fact that it is easily chemically or electrochemicallysynthesized [4ndash7] However PPy presents some structuraldefects during its synthesis such as impurities that maybe incorporated into the polymeric chains or the presenceof ramifications which are the result of nucleophilic attackin positions other than the 2 and 5 positions Thereforeevery time the polymer preferentially grows in the orthoposition it results in branched chains These structuraldefects of the PPy can be minimized by template synthesisIn a template synthesis the host matrix determines the sizespatial orientation and shape of the synthesized polymer [2]Carbon nanotubes (CNTs) were discovered in the 1990s andwere classified as single-walled carbon nanotubes (SWCNTs)and multiwalled nanotubes (MWCNTs) [8] SWCNTs areformed from a rolled graphite leaf with closed extremeswhereas MWCNTs are made up of concentric SWCNTs [9]These materials exhibit excellent morphological electricaloptical thermal chemical and mechanical properties [10]CNTPPy composites have intensified properties owing tothe synergistic effect between the constituent materialsConducting polymers increase the electronic conductivity of

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2015 Article ID 560164 13 pageshttpdxdoiorg1011552015560164

2 Journal of Nanomaterials

the composites and the CNTs mechanically and thermallyreinforce these materials [11]

Wang et al (2007) studied PPySWCNT compositesfor applications as electrodes in symmetric supercapacitorsSpecific discharge capacity values were obtained using cyclicvoltammetry (CV) in 1mol Lminus1 KCl solution at 10mV sminus1The values were 223 and 202 F gminus1 for functionalized andnonfunctionalized SWCNTs respectively During function-alization carboxylic groups can be incorporated into thenanotubes making them hydrophilic [12ndash14] Li et al (2014)demonstrated a three-component CNTPPyMnO

2

spongeelectrode with a controlled thickness and a shell sequencethat was uniformly coated throughout the CNT spongemaintaining the original CNTnetwork and interconnectionsA synergistic effect from the respective components (PPyMnO2

) and the porous conductive CNT network offers thehybrid sponge a superior electrochemical performance The3D CNT network significantly reduces the internal resis-tance of the electrode and maintains its structure stabilityPorous CNTPPyMnO

2

sponges can serve as freestandingcompressible electrodes for supercapacitors as well as otherenergy devices [15]

Dhibar and Das (2014) synthesized a silverminuspolyanilineMWCNT [(AgndashPANI)MWCNT] nanocomposite for high-performance supercapacitor electrodesThe possible interac-tions between Ag and PANI were characterized by Fourier-transform infrared (FT-IR) and UVVisible spectroscopiesMorphological studies confirmed the formation of Agnanoparticles in the PANI surface and the MWCNTs wereuniformly coated by PANI with the presence of Ag nanopar-ticles The nanocomposite showed an improved electricalconductivity of 424 S cmminus1 at room temperature and attainednonlinear current-voltage characteristicsThehighest specificcapacitance obtained for the nanocomposite was 528 F gminus1The nanocomposite also showed better energy and powerdensities AgndashPANICNT-based supercapacitors with out-standing energy and power densities are a potentially promis-ing candidate for future energy-storage systems [16]

Huo et al (2013) synthesized three membrane elec-trodes for supercapacitors in microelectromechanical sys-tems (MEMS) which were made of PPy CNTPPy andgraphenePPy (GRPPy) electrodeposited on Pt current col-lectors Results indicate that there are strong adhesive forcesbetween the electrode materials and the current collectorsThe electrode resistances decrease in the order of PPygtCNTPPygtGRPPy The specific capacitances are 70 80 and83mF cmminus2 at a discharge current of 1mAand their retentionrates after 5000 chargedischarge cycles are 729 850 and892 for PPy CNTPPy and GRPPy respectively [17]

Hu et al (2012) demonstrated that CV scanning couldbe applied to effectively tailor the surface chemistry ofCNTs and to introduce physical defects into the CNTwalls which drastically enhances the electrochemical capac-itance performance of CNTs and their composites withPPy conducting polymer As a consequence the highestcapacitance of 587 F gminus1 was achieved among all of thetested samples which is ten times higher than that of thedefect-free counterparts Electrochemical CV pretreatment

provides an effective approach to activate the CNT surfacesfor enhancing their electrochemical performance meetingdiverse demands and offering new pathways for designingand fabricating high-performance capacitance devices [18]In previous work we synthesized MWCNTs coated withprotonated PANI in situ during the chemical polymerizationof aniline Uniform coating of CNTs with PANI was observedby scanning electron microscopy An improvement in thecovering of the CNT composites was found by the asso-ciation of poly(25-dimercapto-134-thiadiazole) (PDMcT)A maximum conductivity of 968 S cmminus1 has been foundfor a PANIPDMcTCNT composite A high capacitancevalue (2894 F gminus1) was also determined for this compositeindicating that all materials PANI PDMcT andCNT remainactive during chargedischarge cycling The reduction in thecapacitance after 100 cycleswas found to be less than 25 [19]

Thus the objectives of this work were the synthesis of thePPyCNT composites by both chemical and electrochemicalmethods as well as their electrochemical structural and elec-trical characterization The electrochemical performances ofthese electrochemical and chemical composites were testedfor applications as electrodes in Type I supercapacitors usingboth composites as electrodes with the same p-type doping

2 Experimental

21 Functionalization of the MWCNTs MWCNTs (Aldrichdiameter 110ndash170 nm length 5ndash9120583m) were treated with 4mLof a mixture of concentrated HNO

3

and H2

SO4

(1 3 vv) at50∘C for 24 h In sequence the functionalized CNTs werefiltered and dried under vacuum [19] For the compositesynthesis 50mg of CNTs was added to 20mL of the synthesissolution of the polymer containing 0025mol Lminus1 sodiumdodecyl sulfate (SDS) The mixture was dispersed ultrason-ically for 3 h [19]

22 Physical Mixing of the CNTs with PPy PPy powders werephysically mixed with CNTs in a CNTPPy ratio of 20 80(wtwt)

23 Chemical Synthesis of the PPyCNT Composite andPPy For the composite synthesis the pyrrole monomer(01mol Lminus1) was added to 20mL of NaCl (3mol Lminus1) andHCl aqueous solution (1mol Lminus1) containing 50mg of dis-persed CNTs A solution of FeCl

3

(00022mol Lminus1) in NaCl(3mol Lminus1)HCl (1mol Lminus1) was added (20mL) to the reac-tionmedium for 2 hmaintaining the temperature at minus10∘C inorder to secure a higher ordering of the polymer backboneThe precipitate was collected by filtration and then washedwith 1 L of 1mol Lminus1HCl obtaining the conducting stateof the PPyCNTs which was then dried under a dynamicvacuum for 48 h The PPy was synthesized under the sameconditions

24 Electrochemical Synthesis of the PPyCNT Composite andPPyPt For all electrochemical syntheses of the compos-ites and PPy conventional electrochemical cells were used

Journal of Nanomaterials 3

comprising three electrodes a working electrode a platinumcounter electrode and a AgAgCl

(sat) reference electrodeAll electrochemical measurements were performed using aPGSTAT30 Autolab potentiostat

To prepare the CNTPt films the CNT powder was addedto 10 (ww) PVDF in cyclopentanone The mixture washeated to 120∘C to acquire a gelatinous consistency Thenthe platinum was painted with the gel containing the CNTsand subsequently it was heated to 60∘C for 20min in orderto evaporate the solvent Then CV was performed on theCNT film on Pt to ensure that the anodic charge was about5 plusmn 1mCThe anodic films that had anodic charges that werehigher or lower than 5 plusmn 1mC were discarded

The electrochemical synthesis of the PPyCNT binarycomposite was realized by chronoamperometry at 08 V(versus AgAgCl

(sat)) up to an anodic charge of 130mC onthe CNT films (59mC) in 20mL acetonitrile (HPLC grade)which contained 01mol Lminus1 distilled pyrrole 2 deionizedH2

O and 01mol Lminus1 LiClO4

The PPyPt was synthesizedunder the same conditions [21 22]

25 Structural Characterization by FT-IR Spectroscopy FT-IR spectroscopy was performed using an infrared spec-trophotometer (ABB BOMEM MB series) using pellets ofthe composite powder containing KBr (1 100) from 400 to4000 cmminus1

26 Characterization by XRD Analysis The powders werealso characterized by X-ray diffraction (XRD) using a Shi-madzu diffractometer (Model 6000 radiation CuK120572 120582 =15406gt) with a voltage of 40 kV a current of 30mA at2120579minminus1 and within the of 5∘ le 2120579 le 70∘ range

27 Morphological Characterization by SEM SEM imageswere obtained using a Hitachi electronic scanning micro-scope Model 3000 enlarging the images 15000 times withacceleration voltages of 5 and 10 kV

28 Electrochemical Stability of the PPyCNT Composites andConstituent Materials CV The electrochemical stabilities ofthe chemical and electrochemical PPyCNT composites wereevaluated by CV from minus02 to 08 V (versus AgAgCl

(sat))at 100mV sminus1 in ethylene carbonate (EC) and dimethylcarbonate (DMC) (50 vv) containing 1mol Lminus1 LiClO

4

for100 consecutive cycles

29 Characterization of the PPyCNT Composites and Con-stituent Materials EIS Electrochemical impedance spec-troscopy (EIS) spectra were recorded by applying of alter-nating current (AC) amplitude of 10mV and the data werecollected in the frequency range from 10minus3 to 104Hz Allelectrochemical experiments were realized in an AutolabPGSTAT 20 FRA instrument

210 Charge and Discharge Tests of the Devices GalvanostaticChronopotentiometry Before the charge and discharge testsCV was performed to select the electrodes that had similar

anodic charges which could then be used as workingreference and counter electrodes to characterize a Type Isupercapacitor (same materials with similar p-type doping)

The electrochemical characterization of the chemical andelectrochemical composites was performed over five CVscans in ECDMC (50 vv) containing 1mol Lminus1 LiClO

4

at100mV sminus1 using AgAgCl

(sat) as the reference electrodeplatinum as the counter electrode and the composites asworking electrodes This electrochemical characterizationaimed to select the composites that had similar anodiccharges in order to be tested as electrodes in Type I super-capacitors Charge and discharge tests were conducted atdifferent current densities for each conducting compositeand their constituent materials such as 10mA cmminus2 forthe electrochemically synthesized PPyCNT composite and01mA cmminus2 for the chemically synthesized PPyCNT com-posite in the potential range from minus079 to 049V

3 Results and Discussion

31 Electropolymerization of PPy and the PPyCNTCompositeThe electropolymerization of the PPy on CNTPt and PPyPtwas realized by chronoamperometry (Figures 1(a) and 1(b))The anodic charge was set at 130mC plusmn 10mC In thechronoamperogram of the PPyCNT composite (shown inFigure 1(a)) it is observed that current density for the anodicpolypyrrole on Pt (no growth restriction) is much lowerthan that obtained for polypyrrole on CNTPt (with growthrestriction) Therefore the elapsed time for PPyPt achiev-ing the desired anodic charge was much higher than thatobtained for the PPyCNT composite (growth restriction)So this was an indication that the electronic conductivityof the PPyCNT composite (with growth restriction) washigher than for those obtained for PPyPt (no growthrestriction) This occurs due to the formation of branchingin the chain of PPy grown on Pt which compromises itselectronic conductivity Already theCNTs act as a hostmatrixfor the polypyrrole determining its shape size and spatialarrangement thus fostering growth linearly favoring theelectronic conductivity of the resulting film

In Figure 1(b) is an inset of the chronoamperogram forpolymerized PPy on PtThe chronoamperogram shows well-defined regions that is a decrease in the current valueswhich can be attributed to the electric double layer andan increase in the current density as a function of timecorresponding to nucleation and another constant for thegrowth of the conducting polymer [22]

32 Structural Characterization by FT-IR Structural charac-terization of the composites and their constituent materialswas performed by FT-IR (Figure 2) The FT-IR spectrumof the CNTs shows a broad band at 3460 cmminus1 assignedto the OH stretching and an intense band at 1633 cmminus1corresponding to C=O stretching from the carboxylic acidincorporated into the CNTs after functionalization in acidmedium [22]

Already the FT-IR of the PPy shows a vibrational CndashNstretching band at 1404 cmminus1 from the aromatic amine groups


0

1

2

3

4

t (s)

Electrochemical PPyPtElectrochemical PPyCNT

0 300 600 900 1200 1500

130 plusmn 10mC

j(m

A cm

minus2)

(a)

00

1

2

3

4

5

00

01

02

03

04

20 40 60 80t (s)

j(m

A cm

minus2)

j(m

A cm

minus2)

t (s)0 300 600 900 1200 1500


(b)

Figure 1 Chronoamperograms of the (a) PPyPt and PPyCNTs electrochemically synthetized in acetonitrile (HPLC grade) 2 H2

O(deionized) and 01mol Lminus1 LiClO

4

at 08 V (b) Inset of the chronoamperogram for PPy on Pt

CNT

PPy

PPyCNT

PPyCNT

NndashH

NndashH

OndashH

3750 3000 2250 1500 750

Wavenumber (cmminus1)

Tran

smitt

ance

(au

)

chemical

physical

lowastlowast

C=O

lowastC=O

lowastC=O

lowastC=O

CndashCndashO

lowastlowast

lowastlowast

synthesis

mixture

= N+ndashH

= N+ndashH

= N+ndashH

Figure 2 FT-IR spectra of PPy CNTs physical mixture ofPPyCNTs and chemically synthesized PPyCNT composite

and a second vibrational CndashH stretching band between1402 and 1047 cmminus1 The bands that appear in the 3000 to3750 cmminus1 region are related to NndashH stretching in differentenvironments [23] The band at 1201 cmminus1 can be associatedwith ndashNH+= stretching The authors interpreted this stretchto originate from the bipolaronic structure evidencing thepresence of PPy in its conducting form when the PPywas chemically synthesized [24] In addition it is observedthat the FT-IR spectrum of PPyCNTs exhibits a peak at1614 cmminus1 which refers to the association of the CndashC andC=O vibrations in the CNTs Thus from this FT-IR analysis

it is possible to infer that the PPyCNT composite wassuccessfully synthesized

The CNTs were physically mixed with the PPy powder inthe ratio (2 8 ww) in order to compare its IR spectrum withthat obtained for the chemically synthesized composite Itwas observed that the spectrumof the chemically synthesizedcomposite presented OndashH stretching which was slightlyshifted from 1637 cmminus1 (spectra of PPy and physical compos-ite) to 1614 cmminus1 This displacement and the intensification ofthe band at 1197 cmminus1 indicated a higher degree of oxidationof the PPy present in the composite compared to PPy inthe physically mixed constituent materials The presence ofcarboxylic groups on the CNT surface (band at 1614 cmminus1) islikely to result in interfacial interactions between the polymerand the CNTs This is attributed to the hydrogen bondswhich were formed between ndashCOOH groups in chemicallymodified CNTs and =NH+ groups of PPy [20] as shown inFigure 3

33 Characterization by XRD The composites were alsocharacterized by XRDThe XRD pattern of the CNTs shows adiffraction peak at 264∘ which is assigned to the graphiticstructure present in the CNTs and other diffraction peaksare attributed to impurities during themanufacturing processof the CNTs (Figure 4) The XRD pattern of PPy presentedbroad diffraction peaks at 2120579 = 229∘ owing to the pyrroleintermolecular spacing [25] Besides in the XRD pattern ofthe chemical PpyCNT composite it was observed that whenthe CNTs were embedded into the PPYmatrix the peak at 2120579= 21∘ becomes broader and weaker possibly because of thesuperimposition of peaks of the CNTs with a large band ofthe PPy The results from XRD analysis support the presenceof PPy and CNTs in the composite


N

H

+

FeCl3

O

O

HO

HO N

H n

N

H

1M HCl3M NaCl N

H

Figure 3 Polymerization mechanism of PPy on the CNTs (adapted from [20])

100

002

PPyCNT

PPy

CNT

10 20 30 40 50 60 70

2120579 (deg)

Relat

ive i

nten

sitie

s (au

)

Figure 4 XRD patterns of the chemically synthesized PPyCNTcomposite CNTs and PPy

The relative intensities of these reflections are sensitiveto the ring-tilt angle and they are attributed to the ClndashNdistance which is related to the doping level in PPy [20]

34 Morphological Characterization by SEM The SEMimage of the CNTs showed homogeneously scattered beams(Figure 5(a)) Figure 5(b) shows a typical morphology ofPPy The particle size of PPy was 085ndash416 120583m with spher-ical morphology Based on the interaction between pyrrolemonomers and CNTs the pyrrole molecules were adsorbedand polymerized on the surface of the CNTs This processis confirmed by the SEM image of the composite Pyrrolemolecules were adsorbed and polymerized on the surfaceof the CNTs which were wrapped by PPy (Figure 5(c))corroborating the FT-IR data (Figure 2) Therefore it ispredicted that in the presence of CNTs PPy could growaround the CNTs and encapsulate them Compared with theCNTs the diameter of the CNTPPy composite increasedfrom 200 plusmn 10 nm to 550 plusmn 10 nm and the external surfacebecame more rough This morphology is in agreement withthe SEM image shown for PPy coated MWNTs which weresynthesized by Sahoo et al in 2007 [20] Besides polypyrrolenetworks interconnecting nanotubes are not observed The

Table 1 Charge-transfer resistance (119877ct) values of the electro-chemical and chemical PPyCNT composites and their constituentmaterials

Materials 119877ctΩ cmminus2

Electrochemical PPyCNT composite 10Chemical PPyCNT composite 45PPy 55CNTs 75

absence of such polymeric networks indicates that there wasa limited growth of polypyrrole inside and around the CNTs

It was not possible to realize themorphological character-ization of the electrochemical PPyCNT composite owing tothe formation of a very thin film that adhered to the platinumIn the X-ray diffuse scattering (XDS) spectrum the presenceof 117 wt of Cl was observed indicating that the pyrrole waspolymerized on the CNTs in its conducting form and that thecounter ions from the electrolyte (chloride ions) neutralizedthe positive charge density of the formed polymer (Figure 6)Then the PPy was chemically synthesized on the CNTs

35 Electrical Characterization by EIS After structural char-acterization the electrical characterization of the PPyCNTcomposites and their constituent materials was realized byEIS Nyquist diagrams for all of the films are shown inFigure 7 where the inset of Figures 7(a) and 7(c) presentsthe high- and medium-frequency regions for better visu-alization of the electrochemical processes in Figures 7(b)and 7(d) respectively The Nyquist diagrams of PPy and theCNTs showed high impedance values compared with thoseobtained for the electrochemical and chemical CNTPPycomposites The curves obtained for the composites alsoshowed a deviation in slope from a vertical position inrelation to the CNTs and PPy which is attributed to thelow charge-transfer resistance (119877ct) values and may beattributed to the high porosity and mobility of protonsinside the electrodes or a combination of these factors Thisfavored electronic transfer in the conducting compositethus drastically reducing the 119877ct value making them morecapacitive as shown in Table 1 [26] The electrochemically


(a) (b)

(c)

Figure 5 SEM images of (a) PPy (b) CNTs and (c) chemical CNTPPy composite

O ClCl Cl

C

1 2 3 4

Figure 6 XDS spectrum of the chemical CNTPPy composite

synthesized PPyCNT composite showed the lowest 119877ctvalue (10Ω cmminus2) when compared with other materials(Figure 7(d) and Table 1) and presented a predominatelycapacitive profile (Figure 7(a))Then the increase in electrontransfer in this conducting composite is perhaps attributableto the dopant effect or charge transfer from PPy to theCNTs CNTs are relatively good electron accepters whereasPPy can be considered a good electron donor This canbe partially proven by the FT-IR spectrum which suggestsdelocalization of electrons in the composite Also owing tothe large aspect ratio and surface area ofCNTs theymay serveas ldquoconducting bridgesrdquo connecting conducting PPy domains[27] and resulting in higher conductivity thus lowering the119877ct values obtained for these composites [28] (see Figure 7(d)and Table 1) Interestingly both the electrochemical andchemical composites presentedNyquist diagrams with anglesbetween the decline lines and the real axes larger than 45∘

and lower than 90∘ (Figures 7(a) and 7(b)) correspondingto the ion-diffusion mechanism between Warburg diffusionand ideal capacitive ion-diffusion In addition it is foundthat the two decline slopes for the composites are close toeach other at low frequencies implying that both doped andundoped states of PPy are present in the composite whichhave similar geometric capacitanceThis profile demonstratesits application as an electrode in Type I supercapacitors

From the Nyquist diagrams of the electrochemical andchemical PPyCNT composites and their constituent materi-als (Figures 7(b) and 7(d)) the extrapolation of the semicirclewas held in high frequency region in order to obtain thecharge transfer resistance whose values are shown in Table 1

As the chemical and electrochemical PPyCNT compos-ites presented the lowest 119877ct values and capacitive behaviorthey were tested as electrodes in Type I supercapacitors usingcyclic voltammetry and galvanostatic chronopotentiometry

36 Electrochemical Stability by Cyclic Voltammetry Theelectrochemical stability of the composites was evaluated byCV (versus AgAgCl

(sat)) for 100 consecutive cycles Figure 8shows the cyclic voltammograms at 25 50 75 and 100 cyclescorresponding to the stability tests of the electrochemical andchemical PPyCNT composites Both composites presentedcurrent density values that were practically constant In thecyclic voltammograms (Figures 8(a) and 8(b)) higher currentdensity values were observed for the electrochemical com-posite than for the chemical compositesThe electrochemicalcomposites presented a total charge of around 45mC andthe chemical composite was only 25mC showing a higher


Electrochemical PPyCNTChemical PPyCNT

8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)

Z998400 (Ω cmminus2)

10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0


Electrochemical PPyElectrochemical PPyCNT

CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)

Figure 7 Nyquist plots of the (a) electrochemical and chemical PPyCNT composites (b) inset of the Nyquist diagram of the electrochemicaland chemical PPyCNT composites in high frequency region (c) Nyquist diagram of the electrochemical composite and its constituentmaterials and (d) inset of the Nyquist diagram of the electrochemical composite and its constituent materials in high frequency region inECDMC (50 vv) containing 1mol Lminus1 LiClO

4

synergic effect between the constituent materials in thecomposite synthesized through electrochemistry

In the electrochemical stability tests of the electro-chemically synthesized PPyCNT composite and its con-stituent materials after the 100th cycle (in Figures 9(a) and9(b)) both composites presented current density values and

consequently total charges that were higher than thoseobtained for their constituent materials In addition thecurrent density values of the electrochemical compositewere higher than those obtained for chemical composite(Figures 9(a) and 9(b)) This shows that during chemicalsynthesis there was no tight control on the growth of the PPy


00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)

25th cycle50th cycle


E (V versus AgAgCl(sat ))

(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)

Figure 8 Cyclic voltammograms corresponding to the electrochemical stability tests of (a) the electrochemically synthesized PPyCNTcomposite and (b) the chemically synthesized PPyCNT composite in ECDMC (50 vv) containing 1mol Lminus1 LiClO

4

at 100mV sminus1

00 03 06 09minus03

Electrochemical PPyElectrochemical PPyCNTCNT

0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03

Chemical PPyChemical PPyCNTCNT


(b)

Figure 9 Cyclic voltammograms (100th cycle) realized in ECDMC (50 vv) containing 1mol Lminus1 LiClO4

at 100mV sminus1 for (a) theelectrochemical PPyCNT composite and constituent materials and (b) the chemical PPyCNT composite and constituent materials

film during the polymerization reaction Then undesirablefunctional groups and probable ramifications becomepresentin the polymeric chainwhichmay compromise the electronicconductivity of the chemical composite and of the PPy [2930] In the electrochemical synthesis the polymerization ofthe PPy was controlled by application of a specified potentialrange resulting in an ordered polymeric bone which mayhave grownon theCNTs aswell as into theCNTs favoring theformation of a composite with higher electronic conductivityvalues (Figure 9)

Figure 10 exhibits the voltammetric profiles of the chem-ical electrochemical and physical composites The electro-chemical composite presented the highest total charge and avoltammetric profile more capacitive than those obtained for

the chemical and physical composites Furthermore both theelectrochemical and chemical composites presented currentdensity values higher than that obtained for the physicalcomposite indicating a probable interaction between itsconstituent materials (PPy and CNTs) which favors theelectronic conductivity of these composites However theelectrochemical composite had a more capacitive and lessresistive behavior than that obtained for chemical composite

Electrochemical tests of the devices containing chemicaland electrochemical PPyCNT composites weremeasured onthe basis of two-electrode using cyclic voltammetry galvano-static chronopotentiometry and electrochemical impedancespectroscopy This enabled those with similar anodic chargesto be selected for subsequent testing as electrodes in Type


0

3

6

Electrochemical PPyCNTChemical PPyCNTPhysical PPy-CNT

00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075

Chemical PPyCNTPhysical PPy-CNT

00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)

Figure 10 (a) Cyclic voltammograms (100th cycle) realized in ECDMC (50 vv) containing 1mol Lminus1 LiClO4

at 100mV sminus1 for (a) theelectrochemical PPyCNT composite the chemical PPyCNT composite and the physical PPyCNT mixture (b) Cyclic voltammograms ofthe chemical PPyCNT composite and physical PPy-CNT mixture

00

08

16

(A) before(C) before

00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)

Figure 11 (a) Cyclic voltammograms (five cycles) conducted in ECDMC (50 vv) containing 1mol Lminus1 LiClO4

at 100mV sminus1 for theelectrochemical PPyCNT composite ((A) is the device before and (B) is the device after charge and discharge tests) and the chemicalPPyCNT composite ((C) is the device before and (D) is the device after charge and discharge tests) (b) Amplification of the chemicalcomposite device ((C) and (D)) before and after the charge and discharge tests

I supercapacitors (same materials with similar p-doping)(Figure 11) In the cyclic voltammograms of the electrochem-ical PPyCNT composite device the same behavior wasobserved as for the composite electrodes (Figure 8) Thecyclic voltammogram presented an almost constant totalcharge around 1138mC after 50 charge and discharge cyclesindicating good redox reversibility (Figure 11(a)) In additionit was found that the two CV curves almost overlappedwhich implied that there was almost no geometric capaci-tance degeneration after five cycles Therefore the preparedPPyCNT composite has stable cyclic behavior [31]

The cyclic voltammograms for the chemical PPyCNTcomposite exhibited the lowest total charge (0805mC) afterthe charge and discharge tests (Figure 11(b)) The decreasein the values of the total charge compared to the valuesobtained for chemical and electrochemical composites (ver-sus AgAgCl

(sat)) is attributed to the lack of electrochemicalactivation of the electrodes when they were submitted torepeated cycling

The composite electrodes were tested as electrodes inType I supercapacitors (same material with same dopingtype) using the galvanostatic chronoamperometry method


t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)

Charge of the electrochemical PPyCNT at 1mA cmminus2

Discharge of the electrochemical PPyCNT at 1mA cmminus2

Charge of the chemical PPyCNT at 01mA cmminus2

Discharge of the chemical PPyCNT at 01mA cmminus2

(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09

1mA cmminus2Electrochemical PPyCNT atChemical PPyCNT at 01mA cmminus2

E(V

)

(b)

Figure 12 Charge and discharge curves of electrochemical and chemical PPyCNT composites in ECDMC (50 vv) containing1mol Lminus1 LiClO

4

The current densities of the composites and their constituent materials were 10mA cmminus2 for the electrochemicallysynthesized PPyCNT composite and 01mA cmminus2 for the chemically synthesized PPyCNT composite

(Figure 12) The charge and discharge curves of the electro-chemical and chemical PPyCNT composites were observedto be perfectly linear with a low ohmic resistance which indi-cates prominent capacitive behavior in the cell (Figure 12(a))The charge as well as discharge time for the cell was main-tained constant throughout the cycling which demonstratesthat the electrochemical and chemical PPyCNT compositeelectrodes have high electrochemical stability (Figure 12(b))

In the charge and discharge curves of the electrochemicalcomposite and of the constituent materials a decrease in theohmic resistance could be seen owing to the large aspect ratioand surface area of theCNTs whichmay serve as ldquoconductingbridgesrdquo connecting conducting PPy domains and increasingthe electronic conductivity of these materials (Figure 13)

The specific discharge and charge capacities of the com-posites and constituent materials values were obtained by (1)in which 119862 is specific capacitance 119895 is the current density Δ119905is the time range Δ119864 is the potential range and119898 is the massof the electroactive material

119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)

The chemical PPyCNT composite exhibited a specificdischarge capacitance of 270 F gminus1 and power density of6 kWkgminus1 with a coulombic efficiency of 93 after 1000cycles The electrochemical PPyCNT composite deviceobtained an anodic charge of 119876

+

= 1138mC and aspecific discharge capacity of 528 F gminus1 and power densityof 29 kWkgminus1 with a coulombic efficiency of 998 after1000 charge and discharge cycles (Table 2)The power densityvalues of the chemical and electrochemical composites andtheir constituent materials were obtained by (2) in which 119875is power density 119894 is the current density applied to the chargeand discharge tests and an area of 1 cm2 Δ119864 is the potential

PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015

CNT at 05mA cmminus2

Electrochemical PPy at 05mA cmminus2

Electrochemical PPyCNT at 1mA cmminus2

E(V

)

Figure 13 Charge and discharge curves of electrochemical andchemical PPyCNT composites in ECDMC (50 vv) containing1mol Lminus1 LiClO

4

range and 119898 is the mass of the electroactive material Thesevalues are shown in Table 2

119875 =

119894 sdot Δ119864

119898

(2)

This specific discharge capacity value of the electro-chemical composite was higher than the values obtained forthe constituent materials 105 F gminus1 for CNTs and 200 F gminus1for PPy after 50 charge and discharge cycles indicatinggood electroactivity of this composite during the charge anddischarge process (Figure 14)


Table 2 Power density values of the electrochemical and chemical PPyCNT composites and their constituent materials

Materials Specific discharge capacitanceF gminus1 Cycle number Power densitykWkgminus1 Coulombic efficiencyElectrochemical PPyCNT 528 1000 29 9980Chemical PPyCNT 270 1000 6 9300PPy 200 50 12 9250CNT 105 50 7 9810

200 400 600 800 1000

150

300

450

600

Cycle number0

Cc electrochemical PPyCNTCd electrochemical PPyCNTCc chemical PPyCNTCd chemical PPyCNT

Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600

Cc electrochemical PPyCNT

Cc CNT

Cc PPy

Cd electrochemical PPyCNT

Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)

Figure 14 Charge and discharge plots of the specific capacitance values as a function of the cycle number for (a) electrochemical andchemical PPyCNT composites after 1000 cycles and (b) the electrochemical PPyCNT composite and its constituent materials after 50 cyclesThe current densities of the composites and their constituent material were 10mA cmminus2 for the electrochemically synthesized PPyCNTcomposite 01mA cmminus2 for the chemically synthesized PPyCNT composite 05mA cmminus2 for PPy and 01mA cmminus2 for theCNTs in ECDMC(50 vv) containing 1mol Lminus1 LiClO

4

Researchers workingwith conducting polymer electrodesin supercapacitors have obtained a specific discharge capacityof 176 F gminus1 for the electrochemically synthesized PPyCNTcomposite in aqueous solution [32 33] which is lowerthan that obtained for the electrochemically synthesizedcomposite in this work

4 Conclusions

From the FT-IR results of the physical and chemical com-posites similar bands to PPy were observed indicating thatthe conducting polymer was synthesized on the CNTs Inaddition a band at 1130 cmminus1 was observed for the PPyCNTcomposite indicating a high degree of oxidation in PPyand a possible interaction of the surface of the CNTs withthe conjugated structure of the conducting polymer Butcomparing the chemically synthesized composite with thephysical mixture showed displacement and the intensifica-tion of the band at 1197 cmminus1 indicated a higher degree ofoxidation in PPy

The XRD pattern of the composite exhibited two diffrac-tion peaks and the relative intensities of these reflectionswere sensitive to the ring-tilt angle and could be attributedto the ClndashN distance which is related to the doping level ofthe PPy

The SEM images show a spherical profile of the PPy and adiameter increase of the CNT indicating the possible growthof the polymer into of the CNTs showing that the compositewas successfully synthesized

The cyclic voltammograms of the electrodes of thePPyCNT composite showed a predominantly capacitive pro-file with current density values higher than those obtainedfor their constituent materials The electrochemical stabilitytests of the device comprising the electrochemical PPyCNTcomposite (in both electrodes) exhibited a predominantlycapacitive profile according to CV with current densityvalues higher than those obtained for the device madefrom the chemical PPyCNT composite In the charge anddischarge tests the current density for the electrochemicalcomposite was higher than that obtained for the chemicalcomposite Thus the electrochemical composite presented


the highest specific discharge capacitance (528 F gminus1 after1000 cycles) power density (29 kWkgminus1) and 998 coulom-bic efficiency The electrochemical PPyCNT compositeshowed the best electrochemical properties compared to thechemically synthesized composite owing to the synergisticeffect between constituent materials The electrochemicallysynthesized composite showed the lowest impedance valuesand consequently charge-transfer resistance compared tothe chemically synthesized and their constituent materialsindicating that electron transfer in the electrochemicallysynthesized composite was favored by an association betweenthe constituent materials Thus from the characterizationresults using several technics it is possible to state thatthe electrochemically synthesized composite is a promisingmaterial for use as electrodes in Type I supercapacitors

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

Thisworkwas supported by FAPEMIG (GrantsAPQ2279 andEX027-2013)

References

[1] M G Kanatzidis ldquoConductive polymersrdquo Chemical and Engi-neering News vol 68 no 49 pp 36ndash54 1990

[2] D JMaiaM-ADe Paoli O L Alves A J G Zarbin and SDasNeves ldquoSıntese de polımeros condutores em matrizes solidashospedeirasrdquo Quımica Nova vol 23 no 2 pp 204ndash215 2000

[3] E Desimoni B Brunetti P Ugo and R Cazzaniga ldquoA polypyr-roleFe(CN)3minus4minus

6

-coated piezoelectric sensor for Cr(VI)rdquo Syn-thetic Metals vol 130 no 2 pp 135ndash137 2002

[4] Y Kudoh S Tsuchiya T Kojima M Fukuyama and SYoshimura ldquoAn aluminum solid electrolytic capacitor with anelectroconducting-polymer electrolyterdquo Synthetic Metals vol41 no 3 pp 1133ndash1136 1991

[5] C G J Koopal M C Feiters R J M Nolte B de Ruiterand R B M Schasfoort ldquoThird-generation amperometricbiosensor for glucose Polypyrrole deposited within a matrixof uniform latex particles as mediatorrdquo Bioelectrochemistry andBioenergetics vol 29 no 2 pp 159ndash175 1992

[6] B Deore Z D Chen and T Nagaoka ldquoPotential-induced enan-tioselective uptake of amino acid into molecularly imprintedoveroxidized polypyrrolerdquo Analytical Chemistry vol 72 no 17pp 3989ndash3994 2000

[7] E Smela O Inganas and I Lundstrom ldquoControlled foldingof micrometer-sized structuresrdquo Science vol 268 no 5218 pp1735ndash1738 1995

[8] S Iijima ldquoHelicalmicrotubules of graphitic carbonrdquoNature vol354 no 6348 pp 56ndash58 1991

[9] M H Herbst M I F Macedo and A M Rocco ldquoTechnologyof carbon nanotubes trends and perspectives of a multidisci-plinary areardquo Quımica Nova vol 27 no 6 pp 986ndash992 2004

[10] J G V Romero C A Luengo J G Huber and J M RosolenldquoSynthesis of single-wall nanotubes by pyrolysis of graphite in

Helium atmosphererdquo Quımica Nova vol 25 no 1 pp 59ndash612002

[11] E T Thostenson Z Ren and T-W Chou ldquoAdvances in thescience and technology of carbon nanotubes and their compos-ites a reviewrdquoComposites Science and Technology vol 61 no 13pp 1899ndash1912 2001

[12] J Wang Y Xu X Chen and X Sun ldquoCapacitance propertiesof single wall carbon nanotubepolypyrrole composite filmsrdquoComposites Science and Technology vol 67 no 14 pp 2981ndash2985 2007

[13] J Zhao H Park J Han and J P Lu ldquoElectronic propertiesof carbon nanotubes with covalent sidewall functionalizationrdquoJournal of Physical Chemistry B vol 108 no 14 pp 4227ndash42302004

[14] T Ramanathan F T Fisher R S Ruoff and L C BrinsonldquoAmino-fimctionalized carbon nanotubes for binding to poly-mers and biological systemsrdquo Chemistry of Materials vol 17 no6 pp 1290ndash1295 2005

[15] P Li Y Yang E Shi et al ldquoCore-double-shell carbonnanotubepolypyrroleMnO

2

sponge as freestanding com-pressible supercapacitor electroderdquo ACS Applied Materials andInterfaces vol 6 no 7 pp 5228ndash5234 2014

[16] S Dhibar and C K Das ldquoSilver nanoparticles decoratedpolyanilinemultiwalled carbon nanotubes nanocomposite forhigh-performance supercapacitor electroderdquo Industrial andEngineering Chemistry Research vol 53 no 9 pp 3495ndash35082014

[17] X-T Huo P Zhu G-Y Han and J-J Xiong ldquoPreparation andperformance of carbonpolypyrrole membranes as an electrodein supercapacitorsrdquo New Carbon Materials vol 28 no 6 pp414ndash420 2013

[18] YHu Y Zhao Y Li H Li H Shao and LQu ldquoDefective super-long carbon nanotubes and polypyrrole composite for high-performance supercapacitor electrodesrdquo Electrochimica Actavol 66 pp 279ndash286 2012

[19] S C Canobre D A L Almeida C Polo Fonseca and S NevesldquoSynthesis and characterization of hybrid composites based oncarbon nanotubesrdquo Electrochimica Acta vol 54 no 26 pp6383ndash6388 2009

[20] N G Sahoo Y C Jung H H So and J W Cho ldquoPolypyr-role coated carbon nanotubes synthesis characterization andenhanced electrical propertiesrdquo Synthetic Metals vol 157 no 8-9 pp 374ndash379 2007

[21] R A Davoglio S R Biaggio R C Rocha-Filho and N BocchildquoBilayered nanofilm of polypyrrole and poly(DMcT) for high-performance battery cathodesrdquo Journal of Power Sources vol195 no 9 pp 2924ndash2927 2010

[22] D R S Jeykumari S Ramaprabhu and S S Narayanan ldquoAthionine functionalizedmultiwalled carbon nanotubemodifiedelectrode for the determination of hydrogen peroxiderdquo Carbonvol 45 no 6 pp 1340ndash1353 2007

[23] R Rajagopalan and J O Iroh ldquoA one-step electrochemicalsynthesis of polyaniline-polypyrrole composite coatings oncarbon fibersrdquo Electrochimica Acta vol 47 no 12 pp 1847ndash18552002

[24] K S Ryu BWMoon J Joo and SHChang ldquoCharacterizationof highly conducting lithium salt doped polyaniline filmsprepared from polymer solutionrdquo Polymer vol 42 no 23 pp9355ndash9360 2001

[25] J FanMWan D Zhu B Chang Z Pan and S Xie ldquoSynthesischaracterizations and physical properties of carbon nanotubes


coated by conducting polypyrrolerdquo Journal of Applied PolymerScience vol 74 no 11 pp 2605ndash2610 1999

[26] J P Pouget M E Jozefowicz A J Epstein X Tang and A GMacDiarmid ldquoX-ray structure of polyanilinerdquoMacromoleculesvol 24 no 3 pp 779ndash789 1991

[27] W-C Chen and T-C Wen ldquoElectrochemical and capacitiveproperties of polyaniline-implanted porous carbon electrodefor supercapacitorsrdquo Journal of Power Sources vol 117 no 1-2pp 273ndash282 2003

[28] Z Huseyin Z Wensheng J Jianyong et al ldquoCarbon nanotubesdoped polyanilinerdquo Advanced Materials vol 14 no 20 pp1480ndash1483 2000


[30] B Deore Z Chen and T Nagaoka ldquoPotential-induced enan-tioselective uptake of amino acid into molecularly imprintedoveroxidized polypyrrolerdquo Analytical Chemistry vol 72 no 17pp 3989ndash3994 2000

[31] W Sun and X Chen ldquoPreparation and characterization ofpolypyrrole films for three-dimensional micro supercapacitorrdquoJournal of Power Sources vol 193 no 2 pp 924ndash929 2009

[32] M Nagaraja H M Mahesh J Manjanna K Rajanna M ZKurian and S V Lokesh ldquoEffect of multiwall carbon nanotubeson electrical and structural properties of polyanilinerdquo Journal ofElectronic Materials vol 41 no 7 pp 1882ndash1885 2012

[33] R Rajagopalan and J O Iroh ldquoCharacterization of polyaniline-polypyrrole composite coatings on low carbon steel a XPS andinfrared spectroscopy studyrdquo Applied Surface Science vol 218no 1ndash4 pp 58ndash69 2003

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


the composites and the CNTs mechanically and thermallyreinforce these materials [11]

Wang et al (2007) studied PPySWCNT compositesfor applications as electrodes in symmetric supercapacitorsSpecific discharge capacity values were obtained using cyclicvoltammetry (CV) in 1mol Lminus1 KCl solution at 10mV sminus1The values were 223 and 202 F gminus1 for functionalized andnonfunctionalized SWCNTs respectively During function-alization carboxylic groups can be incorporated into thenanotubes making them hydrophilic [12ndash14] Li et al (2014)demonstrated a three-component CNTPPyMnO

2

spongeelectrode with a controlled thickness and a shell sequencethat was uniformly coated throughout the CNT spongemaintaining the original CNTnetwork and interconnectionsA synergistic effect from the respective components (PPyMnO2

) and the porous conductive CNT network offers thehybrid sponge a superior electrochemical performance The3D CNT network significantly reduces the internal resis-tance of the electrode and maintains its structure stabilityPorous CNTPPyMnO

2

sponges can serve as freestandingcompressible electrodes for supercapacitors as well as otherenergy devices [15]

Dhibar and Das (2014) synthesized a silverminuspolyanilineMWCNT [(AgndashPANI)MWCNT] nanocomposite for high-performance supercapacitor electrodesThe possible interac-tions between Ag and PANI were characterized by Fourier-transform infrared (FT-IR) and UVVisible spectroscopiesMorphological studies confirmed the formation of Agnanoparticles in the PANI surface and the MWCNTs wereuniformly coated by PANI with the presence of Ag nanopar-ticles The nanocomposite showed an improved electricalconductivity of 424 S cmminus1 at room temperature and attainednonlinear current-voltage characteristicsThehighest specificcapacitance obtained for the nanocomposite was 528 F gminus1The nanocomposite also showed better energy and powerdensities AgndashPANICNT-based supercapacitors with out-standing energy and power densities are a potentially promis-ing candidate for future energy-storage systems [16]

Huo et al (2013) synthesized three membrane elec-trodes for supercapacitors in microelectromechanical sys-tems (MEMS) which were made of PPy CNTPPy andgraphenePPy (GRPPy) electrodeposited on Pt current col-lectors Results indicate that there are strong adhesive forcesbetween the electrode materials and the current collectorsThe electrode resistances decrease in the order of PPygtCNTPPygtGRPPy The specific capacitances are 70 80 and83mF cmminus2 at a discharge current of 1mAand their retentionrates after 5000 chargedischarge cycles are 729 850 and892 for PPy CNTPPy and GRPPy respectively [17]

Hu et al (2012) demonstrated that CV scanning couldbe applied to effectively tailor the surface chemistry ofCNTs and to introduce physical defects into the CNTwalls which drastically enhances the electrochemical capac-itance performance of CNTs and their composites withPPy conducting polymer As a consequence the highestcapacitance of 587 F gminus1 was achieved among all of thetested samples which is ten times higher than that of thedefect-free counterparts Electrochemical CV pretreatment

provides an effective approach to activate the CNT surfacesfor enhancing their electrochemical performance meetingdiverse demands and offering new pathways for designingand fabricating high-performance capacitance devices [18]In previous work we synthesized MWCNTs coated withprotonated PANI in situ during the chemical polymerizationof aniline Uniform coating of CNTs with PANI was observedby scanning electron microscopy An improvement in thecovering of the CNT composites was found by the asso-ciation of poly(25-dimercapto-134-thiadiazole) (PDMcT)A maximum conductivity of 968 S cmminus1 has been foundfor a PANIPDMcTCNT composite A high capacitancevalue (2894 F gminus1) was also determined for this compositeindicating that all materials PANI PDMcT andCNT remainactive during chargedischarge cycling The reduction in thecapacitance after 100 cycleswas found to be less than 25 [19]

Thus the objectives of this work were the synthesis of thePPyCNT composites by both chemical and electrochemicalmethods as well as their electrochemical structural and elec-trical characterization The electrochemical performances ofthese electrochemical and chemical composites were testedfor applications as electrodes in Type I supercapacitors usingboth composites as electrodes with the same p-type doping

2 Experimental

21 Functionalization of the MWCNTs MWCNTs (Aldrichdiameter 110ndash170 nm length 5ndash9120583m) were treated with 4mLof a mixture of concentrated HNO

3

and H2

SO4

(1 3 vv) at50∘C for 24 h In sequence the functionalized CNTs werefiltered and dried under vacuum [19] For the compositesynthesis 50mg of CNTs was added to 20mL of the synthesissolution of the polymer containing 0025mol Lminus1 sodiumdodecyl sulfate (SDS) The mixture was dispersed ultrason-ically for 3 h [19]

22 Physical Mixing of the CNTs with PPy PPy powders werephysically mixed with CNTs in a CNTPPy ratio of 20 80(wtwt)

23 Chemical Synthesis of the PPyCNT Composite andPPy For the composite synthesis the pyrrole monomer(01mol Lminus1) was added to 20mL of NaCl (3mol Lminus1) andHCl aqueous solution (1mol Lminus1) containing 50mg of dis-persed CNTs A solution of FeCl

3

(00022mol Lminus1) in NaCl(3mol Lminus1)HCl (1mol Lminus1) was added (20mL) to the reac-tionmedium for 2 hmaintaining the temperature at minus10∘C inorder to secure a higher ordering of the polymer backboneThe precipitate was collected by filtration and then washedwith 1 L of 1mol Lminus1HCl obtaining the conducting stateof the PPyCNTs which was then dried under a dynamicvacuum for 48 h The PPy was synthesized under the sameconditions

24 Electrochemical Synthesis of the PPyCNT Composite andPPyPt For all electrochemical syntheses of the compos-ites and PPy conventional electrochemical cells were used














4






4









0

1

2

3

4

t (s)


0 300 600 900 1200 1500

130 plusmn 10mC

j(m

A cm

minus2)

(a)

00

1

2

3

4

5

00

01

02

03

04

20 40 60 80t (s)

j(m

A cm

minus2)

j(m

A cm

minus2)

t (s)0 300 600 900 1200 1500


(b)



4


CNT

PPy

PPyCNT

PPyCNT

NndashH

NndashH

OndashH

3750 3000 2250 1500 750


Tran

smitt

ance

(au

)

chemical

physical

lowastlowast

C=O

lowastC=O

lowastC=O

lowastC=O

CndashCndashO

lowastlowast

lowastlowast

synthesis

mixture

= N+ndashH

= N+ndashH

= N+ndashH







N

H

+

FeCl3

O

O

HO

HO N

H n

N

H

1M HCl3M NaCl N

H


100

002

PPyCNT

PPy

CNT

10 20 30 40 50 60 70

2120579 (deg)

Relat

ive i

nten

sitie

s (au

)











(a) (b)

(c)


O ClCl Cl

C

1 2 3 4










8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials
















4






4









0

1

2

3

4

t (s)


0 300 600 900 1200 1500

130 plusmn 10mC

j(m

A cm

minus2)

(a)

00

1

2

3

4

5

00

01

02

03

04

20 40 60 80t (s)

j(m

A cm

minus2)

j(m

A cm

minus2)

t (s)0 300 600 900 1200 1500


(b)



4


CNT

PPy

PPyCNT

PPyCNT

NndashH

NndashH

OndashH

3750 3000 2250 1500 750


Tran

smitt

ance

(au

)

chemical

physical

lowastlowast

C=O

lowastC=O

lowastC=O

lowastC=O

CndashCndashO

lowastlowast

lowastlowast

synthesis

mixture

= N+ndashH

= N+ndashH

= N+ndashH







N

H

+

FeCl3

O

O

HO

HO N

H n

N

H

1M HCl3M NaCl N

H


100

002

PPyCNT

PPy

CNT

10 20 30 40 50 60 70

2120579 (deg)

Relat

ive i

nten

sitie

s (au

)











(a) (b)

(c)


O ClCl Cl

C

1 2 3 4










8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

1

2

3

4

t (s)


0 300 600 900 1200 1500

130 plusmn 10mC

j(m

A cm

minus2)

(a)

00

1

2

3

4

5

00

01

02

03

04

20 40 60 80t (s)

j(m

A cm

minus2)

j(m

A cm

minus2)

t (s)0 300 600 900 1200 1500


(b)



4


CNT

PPy

PPyCNT

PPyCNT

NndashH

NndashH

OndashH

3750 3000 2250 1500 750


Tran

smitt

ance

(au

)

chemical

physical

lowastlowast

C=O

lowastC=O

lowastC=O

lowastC=O

CndashCndashO

lowastlowast

lowastlowast

synthesis

mixture

= N+ndashH

= N+ndashH

= N+ndashH







N

H

+

FeCl3

O

O

HO

HO N

H n

N

H

1M HCl3M NaCl N

H


100

002

PPyCNT

PPy

CNT

10 20 30 40 50 60 70

2120579 (deg)

Relat

ive i

nten

sitie

s (au

)











(a) (b)

(c)


O ClCl Cl

C

1 2 3 4










8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




N

H

+

FeCl3

O

O

HO

HO N

H n

N

H

1M HCl3M NaCl N

H


100

002

PPyCNT

PPy

CNT

10 20 30 40 50 60 70

2120579 (deg)

Relat

ive i

nten

sitie

s (au

)











(a) (b)

(c)


O ClCl Cl

C

1 2 3 4










8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b)

(c)


O ClCl Cl

C

1 2 3 4










8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





8000

8000

6000

6000

4000

4000

2000

2000

0

0

minusZ998400998400

(Ωcm

minus2)


10minus2 Hz

038Hz

(a)


15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)


(b)

1500

1500

3000

3000

4500

4500

6000

6000

0

0



CNT

minusZ998400998400

(Ωcm

minus2)

10minus2 Hz

038Hz

(c)

15

15

20

20

25

25

0

5

10minusZ998400998400

(Ωcm

minus2)



CNT

(d)


4





00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




00 03 06 09

0

4

8

minus4

minus8

minus03

Q+ = 45 mC

j(m

A cm

minus2)




(a)

000

025

050

075

minus050

minus025

00 03 06 09minus03



j(m

A cm

minus2)

Q+ = 25mC


(b)


4

at 100mV sminus1

00 03 06 09minus03


0

4

8

minus4

minus8

j(m

A cm

minus2)


(a)

00

05

10

minus05

minus10

j(m

A cm

minus2)

00 03 06 09minus03



(b)








0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

3

6


00 03 06 09minus03

minus3

minus6

j(m

A cm

minus2)


(a)

000

025

050

075


00 03 06 09minus03

minus025

minus050

j(m

A cm

minus2)


(b)



00

08

16


00 03 06 09minus03

(A) Q+ = 1195mC

(B) Q+ =1138mC

(C) (D)

minus08

minus16

j(m

A cm

minus2)

(B) after(D) after

E (V)

(a)

00

01

02

(C) before

00 03 06 09minus03

minus01

j(m

A cm

minus2)

(D) Q+ = 0805mC

(C) Q+ = 0870mC

(D) afterE (V)

(b)








t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




t (s)0 3 6 9 1512

06

00

12

minus06

minus12

E(V

)





(a)

t (s)0 40 80 120 160

00

03

06

minus03

minus06

minus09


E(V

)

(b)


4





119862 =

119895 sdot Δ119905

Δ119864 sdot 119898

(1)


+


PPyCNT = 0220V

CNT = 0450V

PPy = 0535V00

03

06

minus03

minus06

minus09

t (s)0 105 3530252015




E(V

)


4


119875 =

119894 sdot Δ119864

119898

(2)





200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






200 400 600 800 1000

150

300

450

600

Cycle number0


Csp

(F cm

minus2)

(a)

010 20 30 40 50

Cycle number0

150

300

450

600


Cc CNT

Cc PPy


Cd CNT

Cd PPy

Csp

(F cm

minus2)

(b)


4


4 Conclusions









Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials







Acknowledgment


References




6















2





























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Research Article Performance of the Chemical and...

Documents

Transcript of Research Article Performance of the Chemical and...