MWCNT Nanocomposite as High Performance

Subscriber access provided by The University of Texas at El Paso (UTEP)

C: Energy Conversion and Storage; Energy and Charge Transport

CuO@NiO/Polyaniline/MWCNT Nanocomposite as High Performance Electrode for Supercapacitor Ishita K Chakraborty, Nilanjan Chakrabarty, Asim Senapati, and Amit K. Chakraborty J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.8b08091 • Publication Date (Web): 01 Nov 2018 Downloaded from http://pubs.acs.org on November 2, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

CuO@NiO/Polyaniline/MWCNT Nanocomposite as High Performance Electrode for Supercapacitor Ishita Chakraborty, Nilanjan Chakrabarty, Asim Senapati, Amit K. Chakraborty* Carbon Nanotechnology Group, Department of Physics, and Centre of Excellence in Advanced Materials, National Institute of Technology, Durgapur-713209, India *Corresponding author Tel.: +91 343 275 4780 Email: [email protected] (Amit K. Chakraborty)

Abstract This work reports facile and well-controlled synthesis of a number of binary, ternary and quaternary nanocomposites using combinations of metal oxides (CuO, NiO), multiwalled carbon nanotubes (MWCNT) and conducting polymer polyaniline (PANI)) for application as electrode in supercapacitor. X-ray diffraction and electron microscopic analyses confirmed the formation of different

composites

NiO@PANI/MWCNT

made and

of

binary

quaternary

CuO@NiO,

ternary

CuO@NiO/PANI/MWCNT

CuO@PANI/MWCNT, nanocomposites.

Such

combination of materials have not been reported previously and with specific capacitance of 1372 Fg-1 and good cyclic stability (83% capacity retention after 1500 cycles) the quaternary nanohybrid electrode shows the best performance compared to all other binary and ternary electrodes tested and promises to be a very good electrode material for supercapacitor application. The improved performance of the quaternary nanocomposite is attributed to the well-designed structural advantages and the synergistic effects of the components that lead to significant reduction in the charge transfer resistance as revealed by electrochemical impedance spectroscopy (EIS). Thus, we show a simple method to control the charge storage capacity of CuO and/or NiO based electrodes by suitable selection of their surface morphology and combining with MWCNT and PANI. The results may have large potential in development of novel electrode materials for supercapacitor using CuO and/or NiO and may be further extended to other transition metal oxide based electrodes.

1 ACS Paragon Plus Environment

The Journal of Physical Chemistry 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 24

1. Introduction In response to the changing global scenario, energy harvesting and storage have become primary focus of the major world powers and scientific community. Great interests have been generated over the past few decades in developing more efficient energy storage devices. One such device, the supercapacitor, has evolved as a strong contender in this context as it promises to bridge the gap between rechargeable batteries and conventional capacitors due to high specific power, moderate energy density, excellent reversibility and long cycle life as compared to batteries1-3. One of the basic

components determining the electrochemical performance of supercapacitors is the electrode which are made with one or more of the three main groups of materials i.e., transition metal oxides/hydroxides, carbonaceous materials, and conducting polymers4-8. Carbon-based materials work as electrical double layer capacitor (EDLC) and offer excellent cyclic stability and long service lifetime due to excellent thermal, mechanical and chemical stability9-12. However, their charge storage capacity is rather limited by the active electrode surface area and pore size distribution due to absence of any chemical reaction. Conducting polymers, although poor in thermal and chemical stability, improves the binding of the metal oxides with carbon materials due to its plastic properties. Conducting polymers also offer benefits as these can be p-doped with (counter) anions when oxidized and n-doped with (counter) cations when reduced13 leading to high charge density. Metal oxides/sulphides/hydroxides are among the most sought after electrode materials as they exhibit high charge storage since the energy is stored in the bulk of the material14-16. Their main limitation is the poor electrical conductivity which leads to slow charge transfer kinetics. As a consequence, carbon materials such as carbon nanotubes, graphene, reduced graphene oxide, carbon black, etc. have been combined with one or more of the other two groups of materials to form hybrid electrodes exhibiting improved specific capacitance and power density17-25. However, of these, only few fabricated the electrode by combining all the three groups of materials21-25. Among various metal oxides, CuO is a good candidate for supercapacitor application as its theoretical pseudocapacitance is very high (about 1800 Fg-1)26 and can be produced with controlled size and shape using simple methods. Previous researchers have shown that the specific capacitance of an electrode strongly depends on the size and shape of the CuO nanostructures used. For example, CuO nanowires showed 118 Fg-1 at 1 Ag-1

27,

nanobelts showed 150 Fg-1 at 1 Ag-1

28,

CuO

nanoflowers showed 130 Fg-1 at 1 Ag-1 29, nanoribbons showed 122 Fg-1 at 1 Ag-1,29 etc. These values are well below the theoretical pseudocapacitance of CuO which suggest the scope for further improvement.


Page 3 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Among carbon materials, CNT is an excellent candidate for supercapacitor electrode owing to its many interesting properties such as high electrical conductivity, large surface area, excellent chemical and mechanical stability and good surface properties9-10,30-32. Thus, many researchers have produced composites MWCNT with CuO or NiO nanostructures for electrode application20,33-35 but often these show poor stability due to poor adhesion with MWCNT. Addition of a polymer which has good conductivity can be very helpful to improve the binding and in turn the stability of the composite.21-25,36 In view of this, we have combined multiwalled carbon nanotubes (MWCNT) as the carbon material, with copper oxide (CuO) as an earth abundant transition metal oxide, and polyaniline (PANI) as a conducting polymer to make electrodes for supercapacitor application. CuO also offers several advantages thanks to its low cost, good chemical stability, non-toxicity and ease of synthesis in various shapes of nanoscale dimensions. PANI has attracted great attention with its unique properties such as tunable electrical conductivity, large surface area, good biocompatibility, ease of preparation, and environmental stability.21,24,25,36-39 It has also been reported to improve the performance of electrode materials for supercapacitor application when combined with porous carbon.40 To improve the specific capacitance of the electrode, some recent studies have reported the use of combination of metal oxides such as Co3O4@MnO241, ZnO@NiO/MoO242, and hence we propose to use mixed CuO/NiO instead of only CuO as NiO has quite high theoretical specific capacitance.43-45 Nanoarchitecture of these oxides (CuO and NiO) when supported with a robust electrical conductor like MWCNT should not only provide large contact area, but also allow fast cations transport between the electrolyte and the electrode. Presence of PANI will further improve the stability of the composite without compromising its conductivity due to the synergistic effects between the various components. Here

we

report

simple

CuO/PANI/MWCNT,

and

cost-effective

NiO/PANI/MWCNT

chemical and

methods

quaternary

to

synthesize

ternary

CuO@NiO/PANI/MWCNT

nanocomposites for application as electrode material in supercapacitor. To the best of our knowledge, this is the first and only instance where CuO, NiO, PANI and MWCNT have been combined to produce composite electrode for supercapacitor. The success of the synthesis of the composites was confirmed using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and energy dispersive x-ray analysis (EDX) which also revealed the structural, morphological and elemental information. Electrochemical studies using cyclic voltammetry (CV) revealed a systematic improvement in the specific capacitance for the ternary and quaternary composite electrodes when compared with those of the individual/binary components 3 ACS Paragon Plus Environment


Page 4 of 24

thus showing the synergistic influence of the components. Electrochemical impedance spectroscopy (EIS) studies showed that the CuO@NiO/PANI/MWCNT quaternary electrode has the lowest charge transfer resistance compared to all other electrodes enabling faster charge transport resulting in the highest specific capacitance.

2. Experimental 2.1.

Materials

Copper sulfate pentahydrate (98%), nickel nitrate hexahydrate (≥98%), ethylene glycol (≥99%), sodium hydroxide pellets (≥97%), urea (99.5%),

sodium dodecyl sulfate (SDS, >90%), and

ammonium persulfate (APS, ≥98%) were purchased from Merck Specialties Pvt. Ltd., aniline hydrochloride (99%) was bought from Loba Chemie Pvt. Ltd. while n-butylamine (98%) was bought from Spectrochem Pvt. Ltd. MWCNTs were procured from Nanostructured & Amorphous Materials, Inc., USA, whose detailed characteristics are available elsewhere.46 2.2.

Synthesis of CuO and NiO

In this procedure, 0.75 g of copper sulfate was first dissolved in 66 mL mixture (6:16 volume ratio) of deionized water and ethylene glycol under stirring to form a homogenous solution. Subsequently, 6 mL of n-butylamine was added under continuous stirring for 60 min. Then, the mixture was transferred into a teflon-lined steel autoclave (100 mL), sealed and heated at 140⁰C for 12h after which it was naturally cooled to room temperature. The product collected from the autoclave was then centrifuged and washed with deionized water and ethanol several times before drying in air at 60⁰C for 12h to get CuO powders. Here, n-butylamine was used both as capping agent to control the growth direction of the initial building blocks of the CuO nanostructure as well as an alkaline reagent. Use of organic compounds (hexamethylene tetramine, Sodium dodecyl benzene sulfonate, etc.) and polymers (polyvinylpyrrolidone, poly(acrylic acid, oleic acid, etc.) is common in the literature for controlling the size and morphology of the synthesized nanostructure.47-51 To synthesize NiO, at first 1.45 gm of nickel nitrate was dissolved in 50 mL of deionized water and stirred for 30 min. Then 30 mL of NaOH(1M) solution was added dropwise under constant stirring to form a homogenous solution and transferred to a teflon-lined autoclave (100 mL) followed by heating at 120C for 12h. After the autoclave cooled down to room temperature, the solution was centrifuged and washed with deionized water and ethanol several times. Finally, the precipitate was calcined in air at 400C for 2h in a muffle furnace to get NiO powders. 2.3.

Synthesis of CuO@NiO nanohybrid

At first, 50 mL aqueous solution of nickel nitrate (4 mM) and urea (0.6 mM) was prepared. 30 mg of as prepared CuO nanoflower was then dispersed into this solution under constant stirring for 60 min 4 ACS Paragon Plus Environment

Page 5 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


at room temperature. Then the solution was transferred into a teflon-lined steel autoclave (100 mL) to heat at 120C for 6h after which it was allowed to cool naturally. Next, the solution was centrifuged and washed with deionized water and ethanol several times. Finally, the material was calcined in air at 350C for 2 h in a muffle furnace. 2.4.

Synthesis of CuO/PANI/MWCNT, NiO/PANI/MWCNT & CuO@NiO/PANI/MWCNT nanocomposites

In the first step, MWCNTs were dispersed using in water using SDS. For this, 40 mg of MWCNTs were sonicated in 40 mL aqueous solution of SDS (0.2 M) in a bath sonicator for 1h. In another two beakers, 320 mg of aniline hydrochloride was dissolved in 20 mL of deionized water and 0.96 gm of APS was dissolved in 20 mL of deionized water separately after which it was cooled to 5⁰C and kept for 2h using an ice bath. Then the aniline hydrochloride solution was added to the MWCNT suspension under constant stirring and further sonicated for 30 min to prevent aggregation of MWCNTs. 40 mg of the as-prepared CuO nanoflower was then added to this solution under constant stirring. Next, 20 ml of APS solution was added dropwise to the above mixture (at 5-10⁰C) for the complete polymerization of aniline. Then the whole suspension was stirred continuously for 6h and the solution was kept in the refrigerator at 0–5⁰C for 36h, filtered and washed successively with deionized water and ethanol to remove the unreacted products. The residue was dried in air at 50⁰C overnight to get the final composite CuO/PANI/MWCNT. To prepare NiO/PANI/MWCNT nanocomposite, we followed the same process as that of CuO/PANI/MWCNT except that instead of CuO, here we added 40 mg of as-prepared NiO. To prepare CuO@NiO/PANI/MWCNT nanocomposite, we followed the same process as that of CuO/PANI/MWCNT except that instead of CuO, here we added 40 mg of as-prepared CuO@NiO. 2.5.

Material Characterizations

XRD data were recorded using a Rigaku-Dmax 2500 diffractometer with Cu Kα radiation (λ= 0.1518 nm). FESEM images were recorded with a Carl Zeiss Sigma scanning electron microscope equipped with a field emission gun and operated at 5 kV. HRTEM images were recorded using a JEOL-JEM 2100 transmission microscope operated at an accelerating voltage of 200 kV coupled with EDX spectrometer. FTIR spectra of the composites were recorded using a Shimadzu IR Prestige-21 spectrometer. The specific surface areas of the samples were measured by BrunauerEmmett-Teller (BET) adsorption/desorption isotherms (N2) using a BET surface analyzer (Nova 1000e) supplied by Quantachrome Instruments, USA.



2.6.

Page 6 of 24

Electrochemical measurements

For electrochemical studies, at first, the working electrodes were prepared by mixing 80 wt% of the active material (the as prepared sample) with 20 wt% of nafion and dispersed in 2-propanol (to obtain a well-mixed slurry) and then drop-casting it on a glassy carbon electrode (3mm dia, CH Instruments) before drying at room temperature for 1h. All the electrochemical measurements were performed on an electrochemical workstation (CH 660E, CH Instruments, USA) at room temperature in a three-electrode cell containing NaOH (3M) aqueous electrolyte in which the as-prepared electrode, platinum wire and Ag/AgCl were used as the working, counter and reference electrodes, respectively. CV tests were performed between 0V and 0.6 V potential at different scan rates. The EIS measurements were carried out in the frequency range from 100 kHz to 0.1 Hz. The specific capacitance of the electrode was calculated from the CV curves according to the following equation: C = (∫I dV) / (mν∆V)

(1)

where, I is the response current density, ∆V is the potential window, ν is the scan rate, and m is the mass of the electroactive material in the electrode (about 8 g) and the active electrode area was 7.07×10-6 m2.

3. Results and discussion Figure 1(a) depicts the XRD plots of CuO, NiO, and CuO@NiO nanostructures in which all the peaks of CuO (black curve) were matched with JCPDS card no. 5-0661 whereas the peaks for NiO (red curve) were matched with JCPDS card no. 47–1049. Absence of additional peaks indicate formation of high purity CuO and NiO phases. For the CuO@NiO sample (blue curve), peaks corresponding to both NiO and CuO can be seen confirming the presence of both these oxides. Figure 1(b) plots the diffraction patterns of PANI, and the ternary and quaternary composites along with that of the binary CuO@NiO nanostructure to help better comparison of the peaks. It is evident that PANI being amorphous in nature gives a broad peak in the region (2θ) 20⁰–30⁰ in accordance with previous literature.24 Diffraction patterns of CuO/PANI/MWCNT, NiO/PANI/MWCNT and CuO@NiO/PANI/MWCNT nanohybrids show presence of peaks corresponding to NiO, CuO and both, respectively. For example, all the sharp peaks observed for 2θ values between 30⁰ and 70⁰ in CuO/PANI/MWCNT sample are due to CuO nanoparticles. Similarly, all the distinct peaks observed for NiO/PANI/MWCNT sample correspond to diffractions from various plane of NiO. For CuO@NiO/PANI/MWCNT sample, the diffraction peaks at 2θ values of 36.6⁰, 42.6⁰, 62.1⁰, 74.8⁰,78.7⁰ are due to (111), (200), (220), (311), (222) planes of NiO, respectively, while the rest of the diffraction peaks originate from the planes of CuO nanocrystals. Absence of characteristic 6 ACS Paragon Plus Environment

Page 7 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


graphitic peak of MWCNT in the ternary and quaternary nanohybrid samples can be understood by noting that the sharpness of this peak is lost due to its coincidence with the broad hump of PANI at 2θ=26⁰. The XRD peaks in Figure 1(b) show small shifts in position upon incorporation of MWCNT/PANI in the sample but not upon formation of the CuO@NiO from their individual oxides (Figure 1(a)). To understand the origin of this shift, we note that observation of small shifts in the XRD peak position of metal oxides upon incorporation of MWCNT have been previously reported by other researchers52-55 which they attributed to good attachment of the metal oxide nanoparticles on the surface of the MWCNTs which could induce strains in the metal oxide lattice.

Figure 1. XRD plots of (a) CuO, NiO, and CuO@NiO nanostructures; (b) CuO@NiO, PANI, NiO/PANI/ MWCNT, CuO/PANI/MWCNT and CuO@NiO/PANI/MWCNT nanohybrid.

The FTIR spectra of the CuO/PANI/MWCNT, NiO/PANI/MWCNT and CuO@NiO/PANI/MWCNT nanocomposites are shown in Fig. 2. The appearance of bands at around 3228–3433 cm-1 and 2851– 2921 cm-1 represents the –NH stretching mode of aromatic amines and asymmetric/symmetric methylene stretching bands, respectively, which originate from the PANI, thus confirming the presence PANI in the sample.56 The characteristic bands at 1562 cm-1 and 1487 cm-1 are attributed to C=C stretching modes of quinoid and benzenoid units of PANI, respectively.56 Similarly, the peaks around 1304 cm-1 and 1242 cm-1 revealed the C=N stretching mode of secondary aromatic amines. Also, the observation of a sharp peak around 1145 cm-1 is a characteristic band of the protonated form of conducting PANI and band at 804 cm-1 originates from the out of plane C–H bending vibration.56 Two dominant peaks at 3432 and 1620 cm-1 which are associated with –OH functional group, shows the presence of MWCNT.24 The sharp feature at 474 cm-1 is due to the presence of Ni– 7 ACS Paragon Plus Environment


O

stretching

which

is

absent

in

the

CuO/PANI/MWCNT

Page 8 of 24

sample

but

present

in

CuO@NiO/PANI/MWCNT clearly confirming the presence of NiO in the later.57 The band at 525 cm-1 is attributable to the stretching vibrations of Cu–O58, indicates the presence of CuO nanoparticles in the CuO/PANI/MWCNT and CuO@NiO/PANI/MWCNT nanocomposites.

Fig.2. FTIR spectra of CuO/PANI/MWCNT, and CuO@NiO/PANI/MWCNT nanocomposites. Fig. 3a shows the FESEM image of the as-synthesized CuO with flower like morphology. The welldefined nanoflowers with diameters of 1–1.5 μm show puffy 3D network structures assembled with many thin nanosheets. Fig. 3b shows the FESEM image of NiO in which thin flake like morphology can be seen. The image in Fig 3c shows the hierarchical CuO@NiO nanohybrid in which it is hard to distinguish the NiO particles from the CuO nanoflowers as NiO flakes seem to sit on the surface of the CuO nanoflowers without causing any visible damage to their flower-like morphology. Fig. 3d shows the FESEM image of the CuO/PANI/MWCNT nanocomposite in which one can clearly see the successful coating of CuO nanoparticles with PANI as well as the presence of well distributed MWCNT network. Fig 3e shows a typical FESEM image of the NiO/PANI/MWCNT sample. Fig. 3e shows a FESEM image of the CuO@NiO/PANI/MWCNT nanocomposite in which one can see the presence of CuO@NiO nanoflower containing well distributed MWCNT network embedded in PANI matrix.


Page 9 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Fig.3. FESEM images of (a) CuO, (b) NiO, (c) CuO@NiO, (d) CuO/PANI/MWCNT, (e) NiO/PANI/MWCNT and (f) CuO@NiO/PANI/MWCNT.

Fig. 4(a) shows the EDX spectrum of the as prepared CuO@NiO nanohybrid which shows presence of Cu, Ni, and O with 27.2, 23.2 and 49.6 atomic percentages, respectively. Fig. 4(b) depicts the EDX spectrum of CuO/PANI/MWCNT which shows presence of Cu, O, C and N in accordance with presence of CuO (Cu & O atoms), PANI (N & C atoms) and MWCNT (C atoms). Fig. 4(c) shows 9 ACS Paragon Plus Environment


Page 10 of 24

the EDX spectrum of NiO in which sharp peaks of O, C, N and Ni confirming presence of NiO. Fig. 4(d) shows the EDX spectrum of the CuO@NiO/PANI/MWCNT nanocomposite in which one can see the presence of Ni in addition to all that observed in Fig. 3(b) confirming the presence of NiO apart from CuO, PANI and MWCNT. The HRTEM image in Fig 4(e) shows presence of metal oxide nanoparticles (dark spots) well attached to the uniformly distributed MWCNT network. CuO@NiO nanoparticles are well bonded to the MWCNT by PANI marix.

Fig.4. EDX spectra of (a) CuO@NiO, (b) CuO/PANI/MWCNT, (c) NiO/PANI/MWCNT, (d) CuO@NiO/PANI/MWCNT and (e) HRTEM image of CuO@NiO/PANI/MWCNT The EDX elemental composition analyses data (Table 1) reveal presence of almost equal (~25%) atomic proportions of Cu and Ni and double amount of O atoms in the CuO@NiO sample in good agreement with expectation. For both CuO/PANI/MWCNT and NiO/PANI/MWCNT samples, one can see that Cu, Ni and O are nearly 24% each while the rest signal came from C and N originating from PANI and MWCNT. The CuO@NiO/PANI/MWCNT sample shows that Cu and Ni are nearly equal in atomic proportion (about 15 wt% each). Table 1: Relative atomic concentrations of various elements present in each of the samples.


Page 11 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Sample CuO@NiO

CuO/PANI/

NiO/PANI/ CuO@NiO/

MWCNT

MWCNT

PANI/MWCNT

Atomic %

Atomic %

Atomic %

Atomic %

Cu

26.20

24.17

Ni

24.15

O

49.65

Elements

15.49 22.78

13.86

23.76

24.37

27.63

N

21.95

23.96

18.83

C

30.12

28.89

24.19

Figure 5(a) shows the CV curves of all the prepared electrode materials within the potential window of 0.0 to 0.6 V at a fixed scan rate of 5mV/s. The CV curves for CuO and CuO@NiO electrodes display pseudocapacitive characteristics, which can be clearly distinguished from the existence of a pair of oxidation and reduction peaks which are absent for the MWCNT sample (which has an ideal rectangular curve, characteristic of EDLC). The CV curves of CuO/PANI/MWCNT and CuO@NiO/PANI/MWCNT show a strong influence of the introduction of MWCNT as the redox peaks diminish in their intensity suggesting that the capacitance comes from both pseudo and EDL capacitance due to the presence of both types of materials. Notably, the integral area of the CV curves increase from CuO electrode to CuO/PANI/MWCNT, and CuO@NiO/PANI/MWCNT electrodes, resulting in a significantly enhanced specific capacitance of the hybrid electrodes. The possible mechanism for the redox reactions of the CuO/Cu(OH)2 and NiO electrode are proposed as follows59,60: 2CuO + H₂O + 2e₋ Cu₂O + 2OH-

(1)

Cu(OH)2 + e₋ Cu(OH) + OH-

(2)

NiO + zOH- zNiOOH + (1z)NiO +ze-

(3)

Figure 5(b) shows the CV curves at different scan rates (5 mV/s ─300 mV/s) within the potential range of 0.0 to 0.6 V for CuO@NiO/PANI/MWCNT electrode only. The peak current increases remarkably with increasing scan rates but the ratio of the anodic to cathodic peak currents (Ia/Ic) remains nearly constant at 0.96 (close to ideal value of unity) for all scan rates which indicates that the redox reaction is quasi-reversible. Figure 5(c) plots the values of log (│Ip│) against log (v) for scan rates of 5 mV/s to 300 mV/s for both cathodic and anodic peaks (Ip is the peak current value for a given scan rate) for the CuO@NiO/PANI/MWCNT sample. To further understand the mechanism of charge storage in the 11 ACS Paragon Plus Environment


Page 12 of 24

CuO@NiO/PANI/MWCNT sample, we note that the electrochemical energy storage is mainly dominated by two processes: capacitive and semi-infinite diffusion and that the peak current density (as estimated from CV curves) obeys a power law with scan rate61 which is given by, 𝑖 = 𝑎𝑣𝑏

(4)

where i and v represent the anodic/cathodic current and scan rate, respectively while a and b are arbitrary constants. Here, if the value of b is 0.5 the charge storage mechanism is said to be governed by diffusion from the outer to inner surface whereas if the value of b is 1, the charge storage is dominated at the surface of the electrode (capacitive process).38 Interestingly, the value of b for anodic and cathodic currents for our CuO@NiO/PANI/MWCNT sample were found to be 0.50 and 0.53, respectively which confirms that the charge storage is diffusion controlled giving clear indication of intercalation of ions during redox reaction. Both the anodic and cathodic peak currents (Ia and Ic, respectively) show a linear dependence on the square root of the scan rates which are depicted in Figure 5 (d). Such behavior generally occurs in case of diffusion of an ionic species in the vicinity of the electrode surface, which defines the rate of the electrochemical reaction.62 The diffusion coefficients have been calculated for all the samples using modified Randle-Sevcick’s equation17,63 for quasi-reversible systems as below: 5

= 2.65 × 10 𝐴𝐶𝑛3/2𝐷1/2𝑣1/2 𝐼𝑞𝑢𝑎𝑠𝑖 𝑝

(5)

where Ipquasi is the peak current for quasi reversible system, A is the electrode area in cm2, C is the concentration of the electrolyte in mol/cm3, n is the number of electrons taking part in the redox reaction (here n=1), D is the diffusion coefficient in cm2/s and ν is the scan rate in V/s. Equation (5) gives the value of diffusion coefficient at scan rate 5 mV/s, D=2.87x10-17 cm2/s for the CuO@NiO/PANI/MWCNT electrode whereas D= 2.92 x10-19 cm2/s and 2.29 x10-18 cm2/s were estimated for bare CuO and NiO nanostructures, respectively. This improvement in the mobility of electrolyte ions into the electrode material can be attributed to introduction of PANI and MWCNT in the composite as compared to the bare CuO and NiO nanostructures. Fig.5e. shows the histogram of the specific capacitance of all the prepared electrode materials. The plot shows that at 5 mV scan rate the highest specific capacitance of 1372 Fg-1 is obtained for the CuO@NiO/PANI/MWCNT electrode and is much higher than that for MWCNT (79 Fg-1), CuO (237 Fg-1), NiO (409 Fg-1), PANI (332 Fg-1), CuO/PANI/MWCNT (682 Fg-1) and NiO/PANII/MWCNT (745 Fg-1). Incorporation of either CuO or NiO in MWCNT/PANI composite results in a significant increase in the specific capacitance of the ternary composite electrodes as PANI acts not only as a pseudocapacitive material but also as a good conductor and as a binder to bind all the components together giving mechanical integrity to the electrode material whereas MWCNTs through the


Page 13 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


formation of a good conducting network ensure a fast charge transfer kinetics, facilitating rapid diffusion and transport of ions.

Figure 5. (a) CV curves (at scan rate 5mV/s), (e) calculated specific capacitance and (f) cycle stability data obtained from various samples. (b) CV curves at different scan rates, (c) log│Ip│ vs log(ν) plot and (d) Ip vs ν1/2 plot for CuO@NiO/PANI/MWCNT electrode.



Page 14 of 24

However, the highest value of specific capacitance is obtained for the quaternary composite CuO@NiO/PANI/MWCNT containing CuO@NiO hybrid nanostructures possibly because the nanoarchitecture of the mixed oxides facilitates larger active catalytic sites and better electrical conductivity due to defects than those of single oxide based ternary composite electrodes. A close look at the CV curves also show that the shapes of the curve for the CuO@NiO/PANI/MWCNT composite is maintained even at a high scan rate of 300 mV/sec indicating good capacitive behavior, rapid diffusion of electrolyte ions from the solution into the pores of the nano-architectured electrode. Although one requires more in-depth investigations to understand the exact nature of interactions between the various components in the multicomponent nanohybrid samples, it is reasonable to speculate that the interactions are largely physical in nature since CuO, NiO and MWCNT are chemically very inert. Since, PANI is also known as a relatively stable conducting polymer, it is likely to act as a binder to all other components thus providing a stronger physical interaction between them in addition to taking part in redox reaction. Presence of MWCNTs provides sites for good attachment of the metal oxide nanostructures through its defects (which are plenty in number as evident from the Raman spectrum available on the supplier’s official webpage46). The long-term stability of the various electrodes was tested by recording the CV curves for upto 1500 cycles at scan rate of 5mV/sec (Fig. 5f). The data shows that upto 83% charge is retained even after 1500 cycles for the CuO@NiO/PANI/MWCNT electrode which confirms good stability and suitability for application as supercapacitor electrode where large number of cycling is required. It is interesting to note that the charge retention is found to be less than 83% after 1500 cycles for all other samples suggesting superior stability of CuO@NiO/PANI/MWCNT sample.

Figure 6. (a) N2 adsorption isotherms for different samples recorded by BET method, (b) specific surface area and average pore sizes of various samples as estimated from the isotherms in (a).


Page 15 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


As surface area of the nanostructures and the pore size play critical role in facilitating the number of active catalytic sites which in turn controls the overall pseudocapacitance of the electrode, in Figure 6(a) we have plotted the N2 adsorption isotherms (by BET method) recorded against CuO, NiO, CuO@NiO and CuO@NiO/PANI/MWCNT. The specific surface areas and average pore sizes as measured from the adsorption isotherms in 6(a) are shown in Figure 6(b). It is evident that both double oxide sample (CuO@NiO) and the quaternary sample showed significantly larger specific surface areas (71 and 67 m2g1, respectively) compared to individual oxides CuO (7 m2g1) and NiO (12 m2g1). Average pore size also showed similar trend as the largest pore sizes were obtained for the CuO@NiO and CuO@NiO/PANI/MWCNT samples (6.16 and 7.07 nm, respectively) as compared to only 4.95 and 3.95 nm for CuO and NiO samples. CuO@NiO being the main constituent of the quaternary sample, and as MWCNT/PANI are common ingredients for both ternary and quaternary samples, it can be safely concluded that the improved surface area of CuO@NiO nanostructure strongly contributes to the improved surface area of the quaternary composite. Together with the presence of conducting MWCNT and PANI, makes the charge transport faster and easier thus exhibiting the best overall electrochemical performance of this sample compared to all others. This is also in good agreement with previous literature in which researchers have shown to increase the electrical conductivity as well as electrochemical performance of various composites by incorporation of PANI and MWCNT.55,64-72

Fig.7. EIS curves for all the samples (expanded to highlight the low frequency region)



Page 16 of 24

In order to further understand what causes of the improved electrochemical performance of the CuO@NiO/PANI/MWCNT electrode, EIS measurements were carried out using each of the electrodes and the corresponding Nyquist plots are compared in Fig. 7 in which one can see that for all samples, there is a semicircle at higher frequency region (low Z) and a rising straight line in the lower frequency region (high Z). The first point of intercept of the semicircles with X-axis in higher frequency region indicates the bulk resistance (Rs) of the electrochemical system comprising of the resistances of the working electrode, electrolyte and electrode/electrolyte interface which is more or less same for all samples except CuO. However, the diameter of the semicircle which is associated with the charge transfer resistance (Rct) shows large variation from sample to sample with CuO@NiO/PANI/MWCNT electrode showing the lowest value of 8 Ω cm-2. Table 2: List of Rct values for different electrode materials as obtained from EIS plot. Electrode materials

Rct (Ω cm-2)

CuO NiO CuO/PANI/MWCNT NiO/PANI/MWCNT CuO@NiO/PANI/MWCNT

59 51 34 19 8

For better comparison, the Rct values of all the samples as calculated from Figure 7 are listed in Table 2 where it is evident that it decreases in a sequential order from CuO and NiO to their ternary composites with its minimum value of 8 Ωcm-2 occurring for CuO@NiO/PANI/MWCNT sample. This indicates that the observed highest specific capacitance of CuO@NiO/PANI/MWCNT electrode is due to the lowest charge transfer resistance caused by the presence of highly conducting MWCNT combined with improved surface morphology of the CuO@NiO nano-architechture and the good stability appears due to good binding of the composite due to the presence of the conducting polymer (PANI). Thus, we have shown a systematic method for controlling the specific capacitance of CuO and/or NiO based electrodes for application in supercapacitor by combining them with carefully selected material with appropriate morphology. To understand the significance of this work with respect to previous reports on similar material combinations, we have compared the results of this work with previously published works in table 3. It is evident that the special nano-architectured composite synthesized in this work compares well with previous works and performs better than many of them showing its suitability as a good material for supercapacitor electrode.


Page 17 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 3: Comparison of the specific capacitance of the electrode prepared in this work with that of similar electrodes reported by other researchers. Electrode material CuO NiO CuO@NiO CuO@NiO CuO/CNT NiO/CNT NiO/PANI CuO/PANI CuO/PANI/rGO NiO/PANI/CNT CuO@NiO/PANI/CNT

Specific Capacitance (F/g) 130 F/g at 1 A/g for nanoflowers 142 F/g at 1 A/g for nanoribbons 480 F/g at 0.5 A/g 370 F/g at 2 mA/cm2 280 F/g at 1 A/g 150 F/g at 1 A/g 630 F/g at 10 mV/s and 650 F/g @ 0.1 A/g 192 F/g at 0.5 A/g 185 F/g at 5 mV/s 634 F/g at 1 A/g 356 F/g at 5 mV/s 1372 F/g at 5 mV/s

Reference 28 44 73 74 27 20 75 76 77 24 This work

4. CONCLUSION In summary, we have reported simple cost-effective chemical methods to synthesize CuO nanoflowers, NiO nanoflakes, and their composites with MWCNT in PANI matrix to give CuO/PANI/MWCNT,

NiO/PANI/MWCNT

and

CuO@NiO/PANI/MWCNT

samples

for

investigation as electrode material in supercapacitor. The structural, morphological and compositional analyses using XRD, FESEM, HRTEM, EDX, and FTIR spectroscopy have confirmed the successful synthesis of the above composites. The highest value of specific capacitance has been observed for CuO@NiO/PANI/MWCNT quaternary nanocomposite (1372 Fg-1 at 5 mV/s scan rate) compared to all other electrodes prepared in this work. BET analysis has shown that the CuO@NiO nanostructure has much larger specific surface area and average pore size compared to those of single CuO and NiO nanostructures. This results in a significant increase in the surface area and pore size of the quaternary CuO@NiO/PANI/MWCNT sample compared to the ternary composites with single oxides. The presence of conductive MWCNT and PANI further improves the electrical conductivity of the quaternary sample for which the EIS analysis provides further support as the charge transfer resistance of the CuO@NiO/PANI/MWCNT electrode is found to be much smaller than all other electrodes. Thus it can be concluded that the improved surface area and reduced charge transfer resistances are the reasons for the improved specific capacitance of the CuO@NiO/PANI/MWCNT electrode. Further, the CuO@NiO/PANI/MWCNT electrode showed upto 83% capacitance retention (highest among others) after 1500 charge–discharge cycles showing good cyclic stability, thus making it a promising electrode material for supercapacitor application. The lowest charge transfer resistance of the CuO@NiO/PANI/MWCNT electrode is the result of a



Page 18 of 24

synergetic influence of the CuO nanoflowers providing large surface area to grow NiO nanoflakes in large quantities, MWCNT facilitating a highly conductive network for rapid charge diffusion and PANI acting as active pseudocapacitive material as well as a good binder to provide stability to the electrode. The results have large potential in development of novel electrode materials for supercapacitor using CuO and/or NiO and may be further extended to other transition metal oxides based electrodes. ACKNOWLEDGMENT The authors acknowledge the MHRD, Govt. of India for the “Centre of Excellence in Advanced Materials” grant of April 2013 under the Technical Education Quality Improvement Programme (TEQIP) phase II for funding this research. .

References (1) (2) (3)

(4)

(5) (6)

(7)

(8)

(9)

Simon, P.; Gogotsi, Y.; Dunn, B. Where Do Batteries End and Supercapacitors Begin? Science 2014, 343 (6176), 1210 LP-1211. Yu, Z.; Tetard, L.; Zhai, L.; Thomas, J. Supercapacitor Electrode Materials: Nanostructures from 0 to 3 Dimensions. Energy Environ. Sci. 2015, 8 (3), 702–730. Zhang, G. Q.; Wu, H. Bin; Hoster, H. E.; Chan-Park, M. B.; Lou, X. W. (David). SingleCrystalline NiCo2O4 Nanoneedle Arrays Grown on Conductive Substrates as Binder-Free Electrodes for High-Performance Supercapacitors. Energy Environ. Sci. 2012, 5 (11), 9453– 9456. Li, Z.; Wang, J.; Wang, Z.; Ran, H.; Li, Y.; Han, X.; Yang, S. Synthesis of a Porous Birnessite Manganese Dioxide Hierarchical Structure Using Thermally Reduced Graphene Oxide Paper as a Sacrificing Template for Supercapacitor Application. New J. Chem. 2012, 36 (7), 1490–1495. Zhang, Y.; Sun, C.; Lu, P.; Li, K.; Song, S.; Xue, D. Crystallization Design of MnO2 towards Better Supercapacitance. CrystEngComm 2012, 14 (18), 5892–5897. Ji, J.; Zhang, L. L.; Ji, H.; Li, Y.; Zhao, X.; Bai, X.; Fan, X.; Zhang, F.; Ruoff, R. S. Nanoporous Ni(OH)2 Thin Film on 3D Ultrathin-Graphite Foam for Asymmetric Supercapacitor. ACS Nano 2013, 7 (7), 6237–6243. Cai, T.; Zhou, M.; Han, G.; Guan, S. Phenol–Formaldehyde Carbon with Ordered/Disordered Bimodal Mesoporous Structure as High-Performance Electrode Materials for Supercapacitors. J. Power Sources 2013, 241, 6–11. Stenger-Smith, J. D.; Lai, W. W.; Irvin, D. J.; Yandek, G. R.; Irvin, J. A. Electroactive Polymer-Based Electrochemical Capacitors Using Poly(Benzimidazo-Benzophenanthroline) and Its Pyridine Derivative Poly(4-Aza-Benzimidazo-Benzophenanthroline) as Cathode Materials with Ionic Liquid Electrolyte. J. Power Sources 2012, 220, 236–242. Frackowiak, E. Carbon Materials for Supercapacitor Application. Phys. Chem. Chem. Phys. 2007, 9 (15), 1774–1785. 18 ACS Paragon Plus Environment

Page 19 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(10) (11)

(12) (13) (14)

(15) (16)

(17) (18)

(19)

(20) (21)

(22)

(23)

(24)

(25)


Chen, T.; Dai, L. Carbon Nanomaterials for High-Performance Supercapacitors. Mater. Today 2013, 16 (7), 272–280. Chakraborty, S.; Saha, S.; Dhanak, V. R.; Biswas, K.; Barbezat, M.; Terrasi, G. P.; Chakraborty, A. K. High Yield Synthesis of Amine Functionalized Graphene Oxide and Its Surface Properties. RSC Adv. 2016, 6 (72), 67916–67924. Chakraborty, A. K.; Coleman, K. S. Poly(Ethylene) Glycol/Single-Walled Carbon Nanotube Composites. J. Nanosci. Nanotechnol. 2008, 8, 4013–4016. Mammone, R. J.; MacDiarmid, A. G. The Aqueous Chemistry and Electrochemistry of Polyacetylene, (CH)X. Synth. Met. 1984, 9 (2), 143–154. Jiang, J.; Li, Y.; Liu, J.; Huang, X.; Yuan, C.; Lou, X. W. (David). Recent Advances in Metal Oxide-Based Electrode Architecture Design for Electrochemical Energy Storage. Adv. Mater. 2012, 24 (38), 5166–5180. Rui, X.; Tan, H.; Yan, Q. Nanostructured Metal Sulfides for Energy Storage. Nanoscale 2014, 6 (17), 9889–9924. H. Yi, H. Wang, Y. Jing, T. Peng, Y. Wang, J. Guo, Q. He, Z. Guo and X. Wang, Advanced asymmetric supercapacitors based on CNT@Ni(OH)2 core–shell composites and 3D graphene networks, J. Mater. Chem. A, 2015,3, 19545-19555 Sarkar, A.; Chakraborty, A. K.; Bera, S. NiS/RGO Nanohybrid: An Excellent Counter Electrode for Dye Sensitized Solar Cell. Sol. Energy Mater. Sol. Cells 2018, 182, 314–320. Sarkar, A.; Chakraborty, A. K.; Bera, S.; Krishnamurthy, S. Novel Hydrothermal Synthesis of CoS2/MWCNT Nanohybrid Electrode for Supercapacitor: A Systematic Investigation on the Influence of MWCNT. J. Phys. Chem. C 2018, 122 (32), 18237–18246. Meriga, V.; Valligatla, S.; Sundaresan, S.; Cahill, C.; Dhanak, V. R.; Chakraborty, A. K. Optical, Electrical, and Electrochemical Properties of Graphene Based Water Soluble Polyaniline Composites. J. Appl. Polym. Sci. 2015, 132 (45). Chakrabarty, N.; Sivaprakash, S.; Chakraborty, A. K. Electrochemical Properties of CNT/NiO Composite. AIP Conf. Proc. 2015, 1665 (1), 50072. Wang, G.; Tang, Q.; Bao, H.; Li, X.; Wang, G. Synthesis of Hierarchical Sulfonated Graphene/MnO2/Polyaniline Ternary Composite and Its Improved Electrochemical Performance. J. Power Sources 2013, 241, 231–238. Hou, Y.; Cheng, Y.; Hobson, T.; Liu, J. Design and Synthesis of Hierarchical MnO2 Nanospheres/Carbon Nanotubes/Conducting Polymer Ternary Composite for High Performance Electrochemical Electrodes. Nano Lett. 2010, 10 (7), 2727–2733. Wang, J.-G.; Yang, Y.; Huang, Z.-H.; Kang, F. Rational Synthesis of MnO2/Conducting Polypyrrole@carbon Nanofiber Triaxial Nano-Cables for High-Performance Supercapacitors. J. Mater. Chem. 2012, 22 (33), 16943–16949. Das, D.; Borthakur, L. J.; Nath, B. C.; Saikia, B. J.; Mohan, K. J.; Dolui, S. K. Designing Hierarchical NiO/PANI-MWCNT Core–Shell Nanocomposites for High Performance Super Capacitor Electrodes. RSC Adv. 2016, 6 (50), 44878–44887. Xia, X.; Hao, Q.; Lei, W.; Wang, W.; Sun, D.; Wang, X. Nanostructured Ternary Composites of Graphene/Fe2O3/Polyaniline for High-Performance Supercapacitors. J. Mater. Chem. 2012, 22 (33), 16844–16850.



(26)

(27)

(28)

(29)

(30) (31)

(32) (33)

(34)

(35) (36)

(37)

(38)

(39)

Page 20 of 24

Chen, K.; Xue, D. Room-Temperature Chemical Transformation Route to CuO Nanowires toward High-Performance Electrode Materials. J. Phys. Chem. C 2013, 117 (44), 22576– 22583. Zhang, X.; Shi, W.; Zhu, J.; Kharistal, D. J.; Zhao, W.; Lalia, B. S.; Hng, H. H.; Yan, Q. High-Power and High-Energy-Density Flexible Pseudocapacitor Electrodes Made from Porous CuO Nanobelts and Single-Walled Carbon Nanotubes. ACS Nano 2011, 5 (3), 2013– 2019. Heng, B.; Qing, C.; Sun, D.; Wang, B.; Wang, H.; Tang, Y. Rapid Synthesis of CuO Nanoribbons and Nanoflowers from the Same Reaction System, and a Comparison of Their Supercapacitor Performance. RSC Adv. 2013, 3 (36), 15719–15726. Vidhyadharan, B.; Misnon, I. I.; Aziz, R. A.; Padmasree, K. P.; Yusoff, M. M.; Jose, R. Superior Supercapacitive Performance in Electrospun Copper Oxide Nanowire Electrodes. J. Mater. Chem. A 2014, 2 (18), 6578–6588. Popov, V. N. Carbon Nanotubes: Properties and Application. Mater. Sci. Eng. R Reports 2004, 43 (3), 61–102. Chakraborty, A. K.; Woolley, R. A. J.; Butenko, Y. V.; Dhanak, V. R.; Šiller, L.; Hunt, M. R. C. A Photoelectron Spectroscopy Study of Ion-Irradiation Induced Defects in Single-Wall Carbon Nanotubes. Carbon 2007, 45 (14), 2744–2750. O’Connell, M.J. Carbon Nanotubes: Properties & Applications. 2006, CRC Press, Boca Raton. Roy, A.; Ray, A.; Saha, S.; Ghosh, M.; Das, T.; Satpati, B.; Nandi, M.; Das, S. NiO-CNT Composite for High Performance Supercapacitor Electrode and Oxygen Evolution Reaction. Electrochim. Acta 2018, 283, 327–337. Lin, P.; She, Q.; Hong, B.; Liu, X.; Shi, Y.; Shi, Z.; Zheng, M.; Dong, Q. The Nickel Oxide/CNT Composites with High Capacitance for Supercapacitor. J. Electrochem. Soc. 2010, 157 (7), A818–A823. Kim, D.-W.; Rhee, K.-Y.; Park, S.-J. Synthesis of Activated Carbon Nanotube/Copper Oxide Composites and Their Electrochemical Performance. J. Alloys Compd. 2012, 530, 6–10. Sawangphruk, M.; Suksomboon, M.; Kongsupornsak, K.; Khuntilo, J.; Srimuk, P.; Sanguansak, Y.; Klunbud, P.; Suktha, P.; Chiochan, P. High-Performance Supercapacitors Based on Silver Nanoparticle–polyaniline–graphene Nanocomposites Coated on Flexible Carbon Fiber Paper. J. Mater. Chem. A 2013, 1 (34), 9630–9636. Agrawalla, R. K.; Paul, S.; Sahoo, P. K.; Chakraborty, A. K.; Mitra, A. K. A Facile Synthesis of a Novel Three-Phase Nanocomposite: Single-Wall Carbon Nanotube/Silver Nanohybrid Fibers Embedded in Sulfonated Polyaniline. J. Appl. Polym. Sci. 2014, 132 (12). Agrawalla, R. K.; Paul, R.; Sahoo, P. K.; Chakraborty, A. K.; Mitra, A. K. A Facile Synthesis of a Novel Optoelectric Material: A Nanocomposite of SWCNT/ZnO Nanostructures Embedded in Sulfonated Polyaniline. Int. J. Smart Nano Mater. 2014, 5 (3), 180–193. Agrawalla, R. K.; Meriga, V.; Paul, R.; Chakraborty, A. K.; Mitra, A. K. Solvothermal Synthesis of a Polyaniline Nanocomposite: a Prospective Biosensor Electrode Material. Exp. Polymer Lett. 2016. 10(9), 780–787.


Page 21 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(40)


Wang, X.; Zeng, X.; Cao, D. Biomass-Derived Nitrogen-Doped Porous Carbons (NPC) and NPC/Polyaniline Composites as High Performance Supercapacitor Materials. Eng. Sci. 2018, 1 (1), 55–63.

(41)

(42)

(43)

(44)

(45)

(46) (47) (48)

(49) (50) (51) (52)

(53) (54)

Liu, J.; Jiang, J.; Cheng, C.; Li, H.; Zhang, J.; Gong, H.; Fan, H. J. Co3O4 Nanowire@MnO2 Ultrathin Nanosheet Core/Shell Arrays: A New Class of High-Performance Pseudocapacitive Materials. Adv. Mater. 2011, 23 (18), 2076–2081. Hou, S.; Zhang, G.; Zeng, W.; Zhu, J.; Gong, F.; Li, F.; Duan, H. Hierarchical Core–Shell Structure of ZnO Nanorod@NiO/MoO2 Composite Nanosheet Arrays for High-Performance Supercapacitors. ACS Appl. Mater. Interfaces 2014, 6 (16), 13564–13570. Wang, H.; Yi, H.; Chen, X.; Wang, X. Facile Synthesis of a Nano-Structured Nickel Oxide Electrode with Outstanding Pseudocapacitive Properties. Electrochim. Acta 2013, 105, 353– 361. Kim, S.-I.; Lee, J.-S.; Ahn, H.-J.; Song, H.-K.; Jang, J.-H. Facile Route to an Efficient NiO Supercapacitor with a Three-Dimensional Nanonetwork Morphology. ACS Appl. Mater. Interfaces 2013, 5 (5), 1596–1603. Paravannoor, A.; Ranjusha, R.; Asha, A. M.; Vani, R.; Kalluri, S.; Subramanian, K. R. V; Sivakumar, N.; Kim, T. N.; Nair, S. V; Balakrishnan, A. Chemical and Structural Stability of Porous Thin Film NiO Nanowire Based Electrodes for Supercapacitors. Chem. Eng. J. 2013, 220, 360–366. Homepage of Nanoamor, Inc. https://www.nanoamor.com/cnts/RS_MWNT_1201YJC.gif Accessed on 27th October, 2018. Zhang, L.; Qin, M.; Yu, W.; Zhang, Q.; Xie, H.; Sun, Z.; Shao, Q.; Guo, X.; Hao, L.; Zheng, Y.; Guo,Z. Heterostructured TiO2/WO3 Nanocomposites for Photocatalytic Degradation of Toluene under Visible Light. J. Electrochem. Soc. 2017, 164 (14), H1086–H1090. Sun, Z.; Zhang, L.; Dang, F.; Liu, Y.; Fei, Z.; Shao, Q.; Lin, H.; Guo, J.; Xiang, L.; Yerra, N.; Guo,Z. Experimental and Simulation-Based Understanding of Morphology Controlled Barium Titanate Nanoparticles under Co-Adsorption of Surfactants. CrystEngComm 2017, 19 (24), 3288–3298. Ma, Y.; Lv, L.; Guo, Y.; Fu, Y.; Shao, Q.; Wu, T.; Guo, S.; Sun, K.; Guo, X.; Wujcik, E. K.; Guo,Z. Porous Lignin Based Poly (Acrylic Acid)/Organo-Montmorillonite Nanocomposites: Swelling Behaviors and Rapid Removal of Pb (II) Ions. Polymer (Guildf). 2017, 128, 12–23. Zhang, L.; Yu, W.; Han, C.; Guo, J.; Zhang, Q.; Xie, H.; Shao, Q.; Sun, Z.; Guo, Z. Large Scaled Synthesis of Heterostructured Electrospun TiO2/SnO2 Nanofibers with an Enhanced Photocatalytic Activity. J. Electrochem. Soc. 2017, 164 (9), H651–H656. Zheng, Y.; Zheng, Y.; Wang, Z.; Cao, Y.; Shao, Q.; Guo, Z. Sodium Dodecyl Benzene Sulfonate-Catalyzed Reaction for Aromatic Aldehydes with 1-Phenyl-3-Methyl-5-Pyrazolone in Aqueous Media. Green Chem. Lett. Rev. 2018, 11 (3), 217–223. Das, D.; Borthakur, L. J.; Nath, B. C.; Saikia, B. J.; Mohan, K. J.; Dolui, S. K. Designing Hierarchical NiO/PAni-MWCNT Core–Shell Nanocomposites for High Performance Super Capacitor Electrodes. RSC Adv. 2016, 6 (50), 44878–44887. Ghanbari, K.; Babaei, Z. Fabrication and Characterization of Non-Enzymatic Glucose Sensor Based on Ternary NiO/CuO/Polyaniline Nanocomposite. Anal. Biochem. 2016, 498, 37–46. Muduli, S.; Lee, W.; Dhas, V.; Mujawar, S.; Dubey, M.; Vijayamohanan, K.; Han, S.-H.; Ogale, S. Enhanced Conversion Efficiency in Dye-Sensitized Solar Cells Based on



(55)

(56)

(57) (58)

(59)

(60)

(61)

(62)

(63) (64)

(65)

(66)

(67)

(68)

Page 22 of 24

Hydrothermally Synthesized TiO2−MWCNT Nanocomposites. ACS Appl. Mater. Interfaces 2009, 1 (9), 2030–2035. Lin, C.; Hu, L.; Cheng, C.; Sun, K.; Guo, X.; Shao, Q.; Li, J.; Wang, N.; Guo, Z. NanoTiNb2O7/Carbon Nanotubes Composite Anode for Enhanced Lithium-Ion Storage. Electrochim. Acta 2018, 260, 65–72. Bushra, R.; Arfin, T.; Oves, M.; Raza, W.; Mohammad, F.; Khan, M. A.; Ahmad, A.; Azam, A.; Muneer, M. Development of PANI/MWCNTs Decorated with Cobalt Oxide Nanoparticles towards Multiple Electrochemical, Photocatalytic and Biomedical Application Sites. New J. Chem. 2016, 40 (11), 9448–9459. Bayal, N.; Jeevanandam, P. Synthesis of CuO@NiO Core-Shell Nanoparticles by Homogeneous Precipitation Method. J. Alloys Compd. 2012, 537, 232–241. Hosseini, S. G.; Abazari, R. A Facile One-Step Route for Production of CuO, NiO, and CuO– NiO Nanoparticles and Comparison of Their Catalytic Activity for Ammonium Perchlorate Decomposition. RSC Adv. 2015, 5 (117), 96777–96784. Vidhyadharan, B.; Misnon, I. I.; Aziz, R. A.; Padmasree, K. P.; Yusoff, M. M.; Jose, R. Superior Supercapacitive Performance in Electrospun Copper Oxide Nanowire Electrodes. J. Mater. Chem. A 2014, 2 (18), 6578–6588. Meher, S. K.; Justin, P.; Ranga Rao, G. Nanoscale Morphology Dependent Pseudocapacitance of NiO: Influence of Intercalating Anions during Synthesis. Nanoscale 2011, 3 (2), 683–692. Lindström, H.; Södergren, S.; Solbrand, A.; Rensmo, H.; Hjelm, J.; Hagfeldt, A.; Lindquist, S.-E. Li+ Ion Insertion in TiO2 (Anatase). 2. Voltammetry on Nanoporous Films. J. Phys. Chem. B 1997, 101 (39), 7717–7722. Zhu, M.; Meng, W.; Huang, Y.; Huang, Y.; Zhi, C. Proton-Insertion-Enhanced Pseudocapacitance Based on the Assembly Structure of Tungsten Oxide. ACS Appl. Mater. Interfaces 2014, 6 (21), 18901–18910. Brownson, D. A. C.; Banks, C. E. The Handbook of Graphene Electrochemistry 2014. Springer. Guan, X.; Zheng, G.; Dai, K.; Liu, C.; Yan, X.; Shen, C.; Guo, Z. Carbon NanotubesAdsorbed Electrospun PA66 Nanofiber Bundles with Improved Conductivity and Robust Flexibility. ACS Appl. Mater. Interfaces 2016, 8 (22), 14150–14159. Wang, C.; Murugadoss, V.; Kong, J.; He, Z.; Mai, X.; Shao, Q.; Chen, Y.; Guo, L.; Liu, C.; Angaiah, S.; et al. Overview of Carbon Nanostructures and Nanocomposites for Electromagnetic Wave Shielding. Carbon N. Y. 2018, 140, 696–733. Song, B.; Wang, T.; Sun, H.; Shao, Q.; Zhao, J.; Song, K.; Hao, L.; Wang, L.; Guo, Z. TwoStep Hydrothermally Synthesized Carbon Nanodots/WO3 Photocatalysts with Enhanced Photocatalytic Performance. Dalt. Trans. 2017, 46 (45), 15769–15777. Gong, K.; Hu, Q.; Xiao, Y.; Cheng, X.; Liu, H.; Wang, N.; Qiu, B.; Guo, Z. Triple Layered Core–shell ZVI@carbon@polyaniline Composite Enhanced Electron Utilization in Cr(vi) Reduction. J. Mater. Chem. A 2018, 6 (24), 11119–11128. Zhang, K.; Li, G.-H.; Feng, L.-M.; Wang, N.; Guo, J.; Sun, K.; Yu, K.-X.; Zeng, J.-B.; Li, T.; Guo, Z.; et al. Ultralow Percolation Threshold and Enhanced Electromagnetic Interference


Page 23 of 24 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(69)

(70)

(71)

(72)

(73) (74) (75) (76)

(77)


Shielding in Poly(l-Lactide)/Multi-Walled Carbon Nanotube Nanocomposites with Electrically Conductive Segregated Networks. J. Mater. Chem. C 2017, 5 (36), 9359–9369. Li, Y.; Zhou, B.; Zheng, G.; Liu, X.; Li, T.; Yan, C.; Cheng, C.; Dai, K.; Liu, C.; Shen, C.; et al. Continuously Prepared Highly Conductive and Stretchable SWNT/MWNT Synergistically Composited Electrospun Thermoplastic Polyurethane Yarns for Wearable Sensing. J. Mater. Chem. C 2018, 6 (9), 2258–2269. Gu, H.; Zhang, H.; Lin, J.; Shao, Q.; Young, D. P.; Sun, L.; Shen, T. D.; Guo, Z. Large Negative Giant Magnetoresistance at Room Temperature and Electrical Transport in Cobalt Ferrite-Polyaniline Nanocomposites. Polymer (Guildf). 2018, 143, 324–330. Luo, Q.; Ma, H.; Hou, Q.; Li, Y.; Ren, J.; Dai, X.; Yao, Z.; Zhou, Y.; Xiang, L.; Du, H.; et al. All-Carbon-Electrode-Based Endurable Flexible Perovskite Solar Cells. Adv. Funct. Mater. 2018, 28 (11), 1706777. Hu, C.; Li, Z.; Wang, Y.; Gao, J.; Dai, K.; Zheng, G.; Liu, C.; Shen, C.; Song, H.; Guo, Z. Comparative Assessment of the Strain-Sensing Behaviors of Polylactic Acid Nanocomposites: Reduced Graphene Oxide or Carbon Nanotubes. J. Mater. Chem. C 2017, 5 (9), 2318–2328. Zhang, Y. X.; Kuang, M.; Wang, J. J. Mesoporous CuO–NiO Micropolyhedrons: Facile Synthesis, Morphological Evolution and Pseudocapcitive Performance. CrystEngComm 2014, 16 (3), 492–498. Huang, M.; Li, F.; Zhang, Y. X.; Li, B.; Gao, X. Hierarchical NiO Nanoflake Coated CuO Flower Core–shell Nanostructures for Supercapacitor. Ceram. Int. 2014, 40 (4), 5533–5538. Razali, S. A.; Majid, S. R. Electrochemical Performance of Binder-Free NiO-PANI on Etched Carbon Cloth as Active Electrode Material for Supercapacitor. Mater. Des. 2018, 153, 24–35. Gholivand, M. B.; Heydari, H.; Abdolmaleki, A.; Hosseini, H. Nanostructured CuO/PANI Composite as Supercapacitor Electrode Material. Mater. Sci. Semicond. Process. 2015, 30, 157–161. Zhu, S.; Wu, M.; Ge, M.-H.; Zhang, H.; Li, S.-K.; Li, C.-H. Design and Construction of Three-Dimensional CuO/Polyaniline/RGO Ternary Hierarchical Architectures for High Performance Supercapacitors. J. Power Sources 2016, 306, 593–601.



Page 24 of 24

TOC Graphic


MWCNT Nanocomposite as High Performance

Recommend Documents