A New Porous Polymer for Highly Efficient Capacitive Energy Storage

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A New Porous Polymer for Highly Efficient Capacitive Energy Storage Piyali Bhanja, Sabuj Kanti Das, Kousik Bhunia, Debabrata Pradhan, Taku Hayashi, Yuh Hijikata, Stephan Irle, and Asim Bhaumik ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.7b02234 • Publication Date (Web): 26 Nov 2017 Downloaded from http://pubs.acs.org on November 27, 2017

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ACS Sustainable Chemistry & Engineering

A New Porous Polymer for Highly Efficient Capacitive Energy Storage Piyali Bhanja,a† Sabuj K. Das,a† Kousik Bhunia,b Debabrata Pradhan,b Taku Hayashi,c Yuh Hijikata,c,d Stephan Irlec,d and Asim Bhaumik*,a a

Department of Materials Science, Indian Association for the Cultivation of Science, 2A & B,

Raja S. C. Mullick Road, Jadavpur 700 032, India. E-mail: [email protected] b

Materials Science Centre, Indian Institute of Technology Kharagpur, Kharagpur−721302,

India c

Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-

ku, Nagoya 464-8602, Japan d

Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-

ku, Nagoya 464-8602, Japan †

These authors contributed equally.

ABSTRACT: A new porous polymer TPDA-1 has been synthesized via solvothermal Schiff base

condensation

reaction

between

two

organic

monomers,

i.e.

2,4,6-

trihydroxyisophthalaldehyde and 1,3,5-tris-(4-aminophenyl)triazine. The TPDA-1 material showed very high specific capacitance of 469.4 F g−1, at 2 mV s−1 scan rate together with high specific surface area of 545 m2 g−1. It also exhibited excellent cyclic stability with 95% retention of its initial specific capacitance after 1000 cycles at 5 A g−1, suggesting its potential as a high performance supercapacitor. Extended π-conjugation and ion conduction inside the micropores throughout the whole polymeric matrix and high BET surface area could be responsible for this high supercapacitor performance in energy storage device. TPDA-1 has been characterized thoroughly by various electrochemical techniques such as cyclic voltammetry, galvanic charge-

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discharge and electrochemical impedance spectroscopy. Our experimental results suggested high potential of this porous polymer in energy storage devices for future generation. KEYWORDS: Covalent organic polymer, electrochemical study, supercapacitor, Schiff base condensation. INTRODUCTION Due to the rapid industrialization, urbanization and population explosion over last few decades, it is highly desirable to develop recyclable and safe sources of energy, as well as advanced and eco-friendly use of conventional energy through energy storage devices. The ease of gaining electricity and sustainability from these intermittent renewable energy storage sources has given them a significant role in energy-applications in recent years.1-3 To obtain a device with high energy density and power, significant interest has been paid for the innovation of redox-active materials for electrochemical supercapacitors.4,5 In the advancement of related technologies, electrochemical capacitors (supercapacitors) are widely applied in electrical vehicles, modern electronic devices, and military devices, comprising of two closely spaced layers with opposing charges.6,7 Electrochemical supercapacitors have the ability to overcome the drawbacks of batteries which possess high energy densities but slow charging performance, and are superior over traditional capacitors, which charge faster but have lower energy density.8,9 Two different processes have been demonstrated to explain the mechanism of electrochemical supercapacitor, one that occurs in the electrochemical double layer (EDLC) and is specified as a non-faradaic process, and the another one, a faradaic process that emerges from electrode bound reversible redox processes in so-called pseudocapacitors.10-12 Recently, carbon based materials ranging from activated carbon to reduced graphene oxide materials are most widely used to for energy


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storage application. In EDLCs, the charge was stored electrostatically using reversible adsorption of ions onto active material surface that are electrochemically stable and have high accessible surface area. As a result, the EDLC offer very high stability during the charge-discharge cycles. However, limited energy density at the electrode surface has been restricted its ultimate practical application. Thus attempts have been paid to exploit carbon-based electrode materials for supercapacitor applications by incorporating redox active materials such as transition metal oxides and conductive polymers.

Subsequently, carbon based transition metal oxide

nanocomposite such as NiO/rGO,13 rGO/carbon,14 Ni(OH)2/MWCNT,15 MnO2/carbon,16 MnO2/rGO,17 Co3O4/rGO,18 Co3O4/MWCNT19 has been synthesized for energy storage applications.20,21 In recent years, porous polymers like covalent organic polymers (COPs) or related ordered covalent organic frameworks (COFs) have attracted immense attention due to their high surface area, consistent nanopores and possibility of designing the network structure using a wide range of functional building blocks.22-25 Quasi-ordered state in the polymer network could be responsible for high charge carrier mobilities.26 These porous polymers found widescale applications in various fields such as catalysis,27 gas storage and separation,28 drug delivery,29 sensing,30 optoelectronics,31 energy storage,32 and so on. COPs/COFs are conventionally prepared using different synthetic routes such as vapor-assisted conversion,33 microwave assisted solvothermal34 and ultrahigh vacuum surface assisted synthesis.35 In this present work, we have synthesized a new porous polymer TPDA-1, through solvothermal poly-condensation reaction by incorporating 2,4,6-trihydroxyisophthalaldehyde moieties into a porous network bearing β-ketoenamines (Scheme 1) and it has been thoroughly characterized. High surface area, tunable porosity and extended π-conjugation of the 2D TPDA-1 polymer is responsible for this three-dimensional porous network material as supercapacitor



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electrode material. The structural and physiochemical properties of as-synthesized TPDA-1 material has been systematically investigated by powder X-ray diffraction, FT-IR, N2 sorption, UV-visible, 13C MAS NMR spectroscopy, HR-TEM, FE-SEM, TG/DTA and CHN analysis. The electrochemical measurements showed that the energy storage ability of TPDA-1 is mainly contributed by the EDLC behavior, which offer excellent electrochemical stability as tested for 1000 charge-discharge cycles. EXPERIMENTAL SECTION Chemicals. Phloroglucinol (M = 126.11 g/mol), phosphoryl chloride (M = 153.33 g/mol) and hexamine (M = 140.18 g/mol) were purchased from Sigma Adrich, India. Further, 4aminobenzonitrile (M = 118.14) and tri-fluoromethanesulfonic acid were also obtained from Sigma Aldrich, India. Organic solvents such as 1,4-dioxane and mesitylene were used as received from Spectrochem, India without further purification. Instrumentation. The X-ray diffraction pattern of the porous polymer was obtained from a Bruker AXS D-8 Advanced SWAX diffractometer using Cu Kα (0.15406 nm) radiation. The Quantachrome Autosorb 1-C was used to obtain N2 sorption isotherms of the TPDA-1 at 77 K and the bulk sample was activated for 12 h at 120 °C under high vacuum conditions to remove any adsorbed solvent molecules. The NLDFT pore-size distribution of TPDA-1 was estimated by employing N2 at 77 K using a slit pore model in the Autosorb-1 software from the resultant N2 adsorption isotherm. To record the FTIR spectra of the porous polymer and the monomers, a Perkin Elmer spectrum 100 spectrophotometer was used. UV-Visible diffuse reflectance spectra were recorded by using a Shimadzu UV 2401PC spectrometer with an integrating sphere attachment where BaSO4 was used as background standard sample. The liquid state 1H and 13C NMR

spectra

of

the

1,3,5-tris-(4-aminophenyl)triazine

(TAPT-1)

and

2,4,64

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trihydroxyisophthalaldehyde (PDA) were recorded in a Bruker Advance 500 MHz NMR spectrometer. The solid state

13

C cross polarization magic angle spinning NMR spectroscopic

(13C CP MAS NMR) measurement was conducted on a Bruker Advance 500 MHz NMR spectrometer using a 4 nm MAS probe at a spinning rate of 5000 Hz, having side band suppression. To observe the structural morphology as well as particle size, FE-SEM analysis was conducted by using a JEOL JEM 6700. The HR-TEM images of the material were recorded using a JEOL 2010 TEM, operated at 200 kV, where the sample was prepared by dropping a sonicated absolute ethanolic suspension over a carbon-coated surface of a copper grid. The TG/DTA analysis was performed employing a temperature ramp of 10 ºC/min with a thermal analyzer TA-SDT Q-600 under air flow. Perkin Elmer 2400 Series II CHN analyzer was used for the elemental analysis. The electrochemical performances of the as-synthesized sample were conducted on a biologic SP-150 electrochemical workstation using three electrode configurations. The electrical conductivity of the sample was measured by 4-probe van der Pauw method using a Nanomagnetic Instruments (ezHEMS, UK). Synthesis of 2,4,6-trihydroxyisophthalaldehyde. Following a literature36 we have prepared the Vilsmeier reagent, where 3.67 g (0.024 mol) of phosphorous oxychloride (POCl3) was added drop-wise to anhydrous DMF (1.75 g, 0.024 mol) with continuous stirring at room temperature (298 K) under inert N2 atmosphere for about 30 minutes. Then the reagent was slowly added to a solution mixture of previously prepared anhydrous 1.0 g (0.008 mol) phloroglucinol in dioxane under a N2 atmosphere (10 mL) maintaining the reaction temperature at ca. 315-320 K. This solution mixture was allowed to stir for 12 h to get a yellow amorphous solid and cooled to 0 °C. Then, this solid mixture was poured to an ice-water slurry (~ 40 mL), allowed to reach room temperature, and stirring was continued for a further 4 h. During this procedure, a cream



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coloured precipitate appeared. Then, the precipitate was filtered off and washed with sufficiently large quantities of distilled water several times. Then, the solid product was dissolved in a very small amount of distilled water, and extracted with ethyl acetate two times. After washing with a brine solution, the obtained organic layer was dried using magnesium sulphate, and the ethyl acetate was removed in a rotary evaporator. The resultant solid was dried under vacuum at 360 K for 16 h to obtain constant weight (1.27 g, 7.0 mmol, 88%); 1H NMR (400 MHz, DMSO-d6) δ ppm 5.87 (s, 1 H, Ar-H), 9.98 (s, 2 H, CHO), 12.48 (br. S., 2 H, OH), 13.48 (br. S., 1 H, OH); 13

C NMR (101 MHz, DMSO-d6) δ ppm 94.1 (C-5), 103.7 (C-1, C-3), 169.0 (C-2), 169.5 (C-4, C-

6), 191.4 (2×CHO); IR (KBr, cm-1) 3083 (br. M), 2975 (br. M), 2890 (br. M), 1639 (s), 1620 (s), 1603 (s), 1440 (s), 1394 (s), 1259 (s), 1193 (s), 804 (s), 611 (s). Synthesis of 1,3,5-Tris-(4-aminophenyl)triazine (TAPT-1). TAPT-1 was synthesized by trimerization of 4-aminobenzonitrile using superacid as a catalyst. Following a standard synthetic procedures,37 1.544 g (13.076 mmol) 4-aminobenzonitrile was placed in a round bottom flask on an ice bath at first. Then, 4 mL (44.4 mmol) of trifluoromethanesulfonic acid was added dropwise very slowly to maintain a temperature of 0 ºC. After 1 h, the resultant slurry was stirred for 24 h at room temperature in an inert N2 atmosphere. After completion of the reaction, 20 mL distilled water was poured to the mixture, followed by neutralization after adding 2 M NaOH solution until a final pH of ~7 was obtained. The pH level was monitored experimentally using litmus paper. The resultant yellow solid product was filtered off using simple filtration techniques and washed with distilled water for 5 times to remove additional NaOH. The purified product has been characterized thoroughly by using FTIR, 1H and

13

C NMR spectroscopy. The

yield was 93.37 mol %.


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Synthesis of porous polymer TPDA-1. The TPDA-1 material was synthesized by using a Schiff-base condensation polymerization method. The reaction was carried out using PDA (0.055 g; 0.3 mmol) and TAPT-1 (0.071 g; 0.2 mmol) in 2 mL of mesitylene and 2 mL of dioxane solvent mixture in the presence of 0.3 mL 3 M acetic acid as catalyst. The reactants were first dispersed in a Pyrex tube by sonication for 10 min to form a completely homogeneous mixture. The reaction mixture was degassed in three subsequent freeze-pump-thaw cycles using liquid nitrogen. After that the tube was flame sealed and kept at 120 °C in an oven for 72 h. Finally, the obtained deep red coloured material was filtered and repeatedly washed with dioxane, water, and acetone, and dried under vacuum at 120 °C for 12 h to obtain TPDA-1. The presence of elements like carbon, hydrogen and nitrogen are revealed by CHN analysis, where C = 69.23 %, H = 4.52 % and N = 13.84 %. This compares favorably with theoretical values for the carbon, hydrogen and nitrogen contents of the TPDA-1 polymer matrix, which are C = 63.12 %, H = 4.30 % and N = 13.39 %. RESULTS AND DISCUSSION Nanostructure analysis. To investigate the crystalline nature of porous polymeric material, powder X-ray diffraction analysis has been has been carried out and this is shown in Figure 1. A broad peak is observed at 2θ value of 5.5° which indicates very low crystalline nature of the material. Another major broad peak was observed from 23o to 28o with maxima at 26.7o which indicating amorphous nature of the TPDA-1. This low crystalline nature of the polymer could be attributed due to the presence of angle strain between two monomers. TAPT-1 is a C3 symmetric triamine and PDA is a dialdehyde which is not linear but bent. So extended hexagonal network formation is geometrically unfavorable. Thus, we observed broad diffraction peaks



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corresponding to the quasi-ordered state for this porous polymer material in contrast to the related crystalline COFs reported in the literature.38 Surface area and porosity analysis. The N2 sorption analysis was employed to measure the specific surface area with architectural rigidity and permanent porosity of the TPDA-1. Figure 2 represents the N2 sorption isotherms of TPDA-1 which was classified as type I isotherm without any hysteresis loop according to IUPAC nomenclature.39 The sharp increase in the N2 uptake at low pressure (0.0 to 0.10 P/P0) indicates the presence of microporosity throughout the material. The Brunauer-Emmett-Teller (BET) surface area and pore volume of the TPDA-1 were estimated to be 545 m2 g-1 and 0.2546 cc g-1, respectively. Also, the pore size distribution plot has been drawn by employing NLDFT (non-local density functional theory) method as shown in the inset of Figure 2. Two sharp peaks appear at 1.4 and 1.6 nm, and one broad peak at 4.1 nm, which are attributed to the existence of micropores and inter-particle mesopores throughout the entire polymer matrix. Moreover, to analyze the microporosity and mesoporosity contribution, De Boer statistical thickness (t-plot) analysis has been performed and reveals surface areas of 513 and 32 m2 g-1, respectively. Solid state 13C MAS NMR analysis. To investigate the chemical environment of various types of carbon atoms in this porous polymer network, solid state have been carried out. The solid state

13

C CP MAS NMR measurements

13

C MAS NMR spectrum of TPDA-1 is displayed in

Figure 3. The more down fielded resonance signals appeared at 185 ppm and 174 ppm due to the presence of carbonyl carbon and the sp2 hybridized carbon atoms adjacent to the triazine ring.40 The sharp signals observed at 170 ppm and 149 ppm are attributed to the hydroxyl groups bearing carbon atoms and sp2 hybridized benzene ring containing carbon atoms adjacent to the – NH groups, respectively. The strong resonance peak at 141 ppm appears due to the existence of 8 ACS Paragon Plus Environment

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enamine carbon atoms. The other sharp signals at 131, 121 and 114 ppm designate the TAPT-1 containing different aromatic carbon atoms. The remaining two sp2 carbon atoms of the phloroglucinol moiety give signals at 108 and 101 ppm. As apparent from Figure 3, there is no characteristic peak observed at ~192 ppm which would indicate the existence of aldehydes group, suggesting the full consumption of the PDA molecule during the Schiff base condensation reaction. Spectroscopic analysis (FTIR and UV-Vis). The FTIR spectral bands of TPDA-1 and starting monomers have been recorded from 4000 cm−1 to 400 cm−1 to characterize the different organic functional groups. In Figure 4a, the broad peak at 3394 cm−1 and sharp signal at 1510 cm−1 corroborate the –N–H stretching and –N–H bending vibration in polymer matrix. The strong adsorption band at 1578 cm−1 could be assigned to the existence of C=C stretching band for ketoenol tautomerization process.41 However, no characteristic stretching band for imine (C=N) group is observed, suggesting the polymeric framework is not composed from the enol form. The absorption peak observed at 1619 cm−1 could be attributed to the formation of α,β-unsaturated ketone in the polymer moiety. For newly formed –C-N groups, the characteristic stretching frequency is observed at 1280 cm−1. The weak signal at 1450 cm−1 appeared due to the presence of C=C stretching vibration of the aromatic benzene rings. The two peaks at 1574 and 1372 cm−1 indicate the presence of the triazine ring in both Figures 4a and 4b. The two separated peaks at 3455 cm−1 and 3323 cm−1 originate from stretching vibrations of primary amine (NH2) groups in as-synthesized TAPT-1. As seen from Figure 4c, the strong adsorption peak at 1644 cm−1 confirms

the

presence

of

carbonyl

(C=O)

stretching

vibration

of

the

2,4,6-

trihydroxyisophthalaldehyde compound containing aldehyde (CH=O) groups. The remaining hydroxyl (-OH) groups of the 2,4,6-trihydroxyisophthalaldehyde moiety are noticeable by 3433



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cm−1 stretching vibrations in both Figures 4a and 4c. Moreover, the absence of a distinctive absorption signal at 2235 cm−1 for –C≡N group suggests the successful synthesis of the TAPT-1 molecule. The UV-visible reflectance spectrum of TPDA-1 in Figure S1 of the electronic supporting information (ESI) showed the broad peak at 550 nm due to n→π* transition of polymer containing heteroatom.42 Further, another broad absorption peak from 300 to 400 nm could be attributed to the π→π* transition of conjugated system adjacent to different heteroatoms.43 Furthermore, the band gap has been estimated as 1.6 eV by employing the UVvisible spectrum and this is shown in the inset of Figure S1. Microscopic analysis. To investigate the structural morphology of TAPT-1, field emission scanning electron microscopy (FE-SEM) technique has been employed. Figures 5a and 5b represent the FE-SEM images of TPDA-1 at two different magnifications. As seen from Figure 5a, sphere-like particles are self-assembled to form large agglomerated particles. Further, high resolution transmission electron microscopy (HR-TEM) was used to analyze the nanoscale porosity in the polymer matrix. The HR-TEM images of the TPDA-1 polymer are shown in Figures 6a and 6b, where presence of micropores are seen throughout the material together with hollow sphere like particle morphology. Thermal stability and elemental analysis. In order to investigate the thermal stability of TPDA-1, TG/DTA has been performed using a temperature ramp of 10 ºC per minute under air flow in the temperature range of 25-800 ºC. Figure S2 represents the TG/DTA profile diagram of TPDA-1, where the first weight loss at 98 ºC could be attributed to the evaporation of surface adsorbed moisture, and the second weight loss up to 400 ºC is attributed to the decomposition of organic functional groups. The third weight loss from 400-800 ºC temperature indicates


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combustion of the residual parts of the sample. Thus, TG/DTA analysis results indicate that TPDA-1 possesses a good thermal stability. Electrochemical study. Electrochemical energy storage performance of the as-synthesized TPDA-1 was measured on a BioLogic SP-150 electrochemical workstation using three electrode configuration, where a TPDA-1 coated graphite sheet was used as working electrode, Pt wire was used as counter electrode, and a saturated calomel electrode (SCE) was used as reference electrode. The graphite sheet (thickness 0.25 mm) was procured from Nickunj Eximp Entp P Ltd, India. The working electrode was prepared by drop casting aliquot electrode materials over 1 cm2 graphite sheet. Aliquot was prepared by dispersing 4 mg of material in 1 mL ethanol with 20 µL of 5% Nafion solution. The TPDA-1 was tested as electrode material for the energy storage application by standard cyclic voltammetry (CV), galvanic charge discharge (GCD), and electrochemical impedance study (EIS). The CV was conducted in 1M H2SO4 as electrolyte with a potential window of 0 to 1 V. Corresponding CV curve is presented in Figure 7. The shape of the CV curve indicates EDLC type charge storage behavior of the TPDA-1. In order to measure the performance of the TPDA-1 in terms of charge storage capability, CV was performed at different scan rates between 2 mV/s ─ 100 mV s−1. From the CV curves, the specific capacitance of TPDA-1 was estimated using the following equation and this is shown in Figure 8. Csp= (∫I×dV)/νmV where, I is the response current, V is the potential window, ν is the potential scan rate, and m is the mass of the active material. The highest capacitance value obtained at 2 mV s−1 scan rate was 469.4 F g−1, which was found to be decreased with increasing the scan rate (Figure 8). This is because of fewer number of electrolyte ions undergoes diffusion and adsorption on the electrode surface at a higher scan rate.44,45 The high specific capacitance of TPDA-1 could be attributed to 11 ACS Paragon Plus Environment


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the presence of π-conjugated system in it, which facilitates electrical conductivity and ion adsorption.46,47 The electrical conductivity of the as-synthesized TPDA-1 was 0.05 ± 0.002 ohm-1 m-1 at room temperature. Details of the energy storage ability of TPDA-1 were further studied from GCD measurements. The GCD behavior over different load current density is presented in Figure 9A. The charge-discharge curve exhibit an equilateral triangle shapes, suggesting EDLC behavior and a good rate reversibility of the electrode material during the charge-discharge process. The specific capacitance (Csp) from the GCD plots was estimated from the discharge slope using the following equation. Csp = (I×∆t)/(∆V×m) where I is the load current density, ∆t is the discharge time, ∆V is the potential window and m is the mass of the active materials. In Figure 9B, the estimated specific capacitance of TPDA-1 electrode was plotted as a function applied current densities. At a specific current density of 0.5 A g−1, the estimated specific capacitance was found to be 348 F g−1. The TPDA-1 obviously was able to store charge via electrostatic attachment/adsorption at the electrode surface. The obtained specific capacitance was found to be comparable with nitrogen doped graphitic carbon (255 F g−1@2 A g−1),48 porous carbon derived from MOF (233 F g-1 @2 A g−1),49 amorphous terephthalonitrile derived nitrogen rich network (298 F g−[email protected] A g−1),50 benzimidazole grafted graphene (410 F g−[email protected] A g−1),51 and nitrogen enriched porous carbon sphere (388 F g−1@1 A g−1).52 The present result is also comparable with the state-of-the-art nanostructures material MnO2/rGO (242 F g−1@1 A g−1),53 TiO2/rGO (255 F g−[email protected] A g−1),54 Fe3O4 nanosheet on one dimensional carbon nanofibers (135 F g−[email protected] A g−1),55 and Fe3O4 nanoparticles (207 F g−[email protected] A g−1).56 Moreover, compared to benzimidazole-based COP material TpDAB (specific


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capacitance of 335 F g−1 at 2 mV s−1 scan rate)57 this TPDA-1 displayed a considerable enhancement in supercapacitor performance (specific capacitance to 469.4 F g−1 at 2 mV s−1 scan rate). It is known that the pore size, surface functional groups, and the surface electrolyte accessibility play important roles for the electrical double layer performance. The well-organized pore distribution in stacked 2D layers of COP creates huge interstitial space for free transport of electrolyte ions and provides more number of surface active sites on TPDA-1 to accommodate charges. Hence EDLC behavior is predominantly the charge storage mechanism for TDPA-1. The cycle stability of the TPDA-1 was tested with up to 1000 charge-discharge cycle GCD at a fixed current density of 5 A g−1 as presented in Figure 10. TPDA-1 retains 95% of the capacitance after 1000 cycle, revealing good stability. The interfacial electrochemical properties of TPDA-1 were studied using EIS. The EIS was carried out at a frequency range of 100 kHz to 100 mHz as presented in Figure 11. The typical Nyquist plot consists of two distinct regions: (1) a small semicircle in the high to medium frequency region, indicating the charge transport resistance, where the starting cross point indicate the contact resistance and (2) the straight line at the low frequency region corresponding to the ion diffusion/transport at the electrode electrolyte interface The vertical lines with small semicircle indicate the charge transport with good capacitive behavior without any diffusion limitation.52,58,59 CONCLUSION Our experimental results suggested that a new highly stable porous polymer can be synthesized through the solvothermal Schiff base condensation reaction between two organic monomers, i.e. 2,4,6-trihydroxyisophthalaldehyde and 1,3,5-tris-(4-aminophenyl)triazine. This porous polymer material exhibited excellent energy storage capacity with a maximum specific capacitance of 13 ACS Paragon Plus Environment


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469.4 F g −1 at 2 mV s−1 scan rate. It also provides very good cyclic stability with 95% retention of its initial specific capacitance after 1000 cycles, recommending the future potential of this porous polymer in designing a sustainable energy storage device. ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: 1

H and

13

C NMR of PDA and TAPT, UV-visible spectrum, TG/DTA profile, electrochemical

data over TPDA-1 (PDF). AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. †These authors contributed equally. ACKNOWLEDGMENT PB thanks to CSIR, New Delhi for a senior research fellowship. SKD thanks to UGC, New Delhi for a senior research fellowship. AB wishes to thank DST, New Delhi for instrumental facilities through DST Unit on Nanoscience.


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REFERENCES (1)

Dunn, B.; Kamath, H.; Tarascon, J. –M. Electrical Energy Storage for the Grid: A Battery of Choices. Science 2011, 334, 928-935. DOI: 10.1126/science.1212741

(2)

Arico, A. S.; Bruce, P.; Scrosati, B.; Tarascon, J. –M.; Schalkwijk, W. V. Nanostructured Materials For Advanced Energy Conversion and Storage Devices. Nat. Mater. 2005, 4, 366-377. DOI: 10.1038/nmat1368

(3)

Liu, X. B.; Wen, N.; Wang, X. L.; Zheng, Y. Y. A High-Performance Hierarchical Graphene@Polyaniline@Graphene Sandwich Containing Hollow Structures for Supercapacitor Electrodes. ACS Sustainable Chem. Eng. 2015, 3, 475-482. DOI: 10.1021/sc5006999

(4)

Wang, C.; Xi, Y.; Wang, M.; Zhang, C.; Wang, X.; Yang, Q.; Li, W.; Hu, C.; Zhang, D. Carbon-Modified Na2Ti3O7·2H2O Nanobelts as Redox Active Materials for HighPerformance

Supercapacitor.

Nano

Energy

2016,

28,

115-123.

DOI:

10.1016/j.nanoen.2016.08.021 (5)

Mulzer, C. R.; Shen, L.; Bisbey, R. P.; McKone, J. R.; Zhang, N.; Abruña, H. D.; Dichtel, W. R. Superior Charge Storage and Power Density of a Conducting PolymerModified Covalent Organic Framework. ACS Cent. Sci. 2016, 2, 667-673. DOI: 10.1021/acscentsci.6b00220

(6)

Zhang, L. L.; Zhao, X. S. Carbon-Based Materials as Supercapacitor Electrodes. Chem. Soc. Rev. 2009, 38, 2520-2531. DOI: 10.1039/B813846J

(7)

Simon, P.; Gogotsi, Y. Materials for Electrochemical Capacitors. Nat. Mater. 2008, 7, 845-854. DOI: 10.1038/nmat2297

(8)

Makino, S.; Yamauchi, Y.; Sugimoto, W. Synthesis of Electro-Deposited Ordered



Page 16 of 36

Mesoporous Ruox Using Lyotropic Liquid Crystal and Application Toward MicroSupercapacitors.

J.

Power

Sources

2013,

227,

153-160.

DOI:

10.1016/j.jpowsour.2012.11.032 (9)

Hu, C. C.; Chen, W. C.; Chang, K. H. How to Achieve Maximum Utilization of Hydrous Ruthenium Oxide for Supercapacitors. J. Electrochem. Soc. 2004, 151, A281A290. DOI: 10.1149/1.1639020

(10)

Khattak, A. M.; Yin, H.; Ghazi, Z. A.; Liang, B.; Iqbal, A.; Khan, N. A.; Gao, Y.; Li, L.; Tang, Z. Three Dimensional Iron Oxide/Graphene Aerogel Hybrids as All-SolidState Flexible Supercapacitor Electrodes. RSC Adv. 2016, 6, 58994-59000. DOI: 10.1039/C6RA11106H

(11)

Paraknowitsch, J. P.; Thomas, A. Doping Carbons Beyond Nitrogen: An Overview of Advanced Heteroatom Doped Carbons with Boron, Sulphur and Phosphorus for Energy Applications. Energy Environ. Sci. 2013, 6, 2839-2855. DOI: 10.1039/C3EE41444B

(12)

Merlet, C.; Rotenberg, B.; Madden, A. P.; Taberna, L. P.; Simon, P.; Gogotsi, Y.; Salanne, M. On the Molecular Origin of Supercapacitance in Nanoporous Carbon Electrodes. Nat. Mater. 2012, 11, 306-310. DOI: 10.1038/nmat3260

(13)

Luan, F.; Wang, G.; Ling, Y.; Lu, X.; Wang, H.; Tong, Y.; Liu, X. –X.; Li, Y. High Energy Density Asymmetric Supercapacitors with a Nickel Oxide Nanoflake Cathode and a 3D Reduced Graphene Oxide Anode. Nanoscale 2013, 5, 7984-7990. DOI: 10.1039/C3NR02710D

(14)

Cheng, J. H.; Chen, Y. H.; Yeh, Y. S.; Hy, S.; Kuo, L. Y.; Hwang, B. J. Enhancement of Electrochemical Properties by Freeze-dried Graphene Oxide via Glucose-assisted Reduction.

Electrochemica

Acta

2016,

197,

146-151.

DOI:


Page 17 of 36 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


10.1016/j.electacta.2015.12.116 (15)

Dubal, D. P.; Gund, G. S.; Lokhande, C. D.; Holze, R. Decoration of Spongelike Ni(OH)2 Nanoparticles onto MWCNTs Using an Easily Manipulated Chemical Protocol for

Supercapacitors.

ACS

Appl.

Mater.

Interfaces

5,

2013,

2446-2454.

DOI: 10.1021/am3026486 (16)

Reddy, A. L. M.; Shaijumon, M. M.; Gowda, S. R.; Ajayan, P. M. Coaxial MnO2/Carbon Nanotube Array Electrodes for High-Performance Lithium Batteries. Nano Lett. 2009, 9, 1002-1006. DOI: 10.1021/nl803081j

(17)

Ye, K. –H.; Liu, Z. –Q.; Xu, C. –W.; Li, N.; Chen, Y. –B.; Su, Y. –Z. MnO2/Reduced Graphene

Oxide

Supercapacitors.

Composite Inorg.

as

Chem.

High-Performance Commun.

Electrode

2013,

30,

for 1-4.

Flexible DOI:

10.1016/j.inoche.2012.12.035 (18)

Guan, Q.; Cheng, J.; Wang, B.; Ni, W.; Gu, G.; Li, X.; Huang, L.; Yang, G.; Nie, F. Needle-like Co3O4 Anchored on the Graphene with Enhanced Electrochemical Performance for Aqueous Supercapacitors. ACS Appl. Mater. Interfaces 2014, 6, 76267632. DOI: 10.1021/am5009369

(19)

Wang, X.; Li, M.; Chang, Z.; Yang, Y.; Wu, Y.; Liu, X. Co3O4@MWCNT Nanocable as Cathode with Superior Electrochemical Performance for Supercapacitors. ACS Appl. Mater. Interfaces 2015, 7, 2280-2285. DOI: 10.1021/am5062272

(20)

Choi, N. S.; Chen, Z.; Freunberger, S. A.; Ji, X.; Sun, Y. K.; Amine, K.; Yushin, G.; Nazar, L. F.; Cho, J.; Bruce, P. G. Challenges Facing Lithium Batteries and Electrical Double-Layer

Capacitors.

Angew.

Chem.,

Int.

Ed.

2012,

51,

9994-10024.

DOI: 10.1002/anie.201201429



(21)

Page 18 of 36

Wang, G.; Zhang, L.; Zhang, J. A Review of Electrode Materials for Electrochemical Supercapacitors. Chem. Soc. Rev. 2012, 41, 797-828. DOI: 10.1039/C1CS15060J

(22)

Wu, D. C.; Xu, F.; Sun, B.; Fu, R. W.; He, H. K.; Matyjaszewski, K. Design and Preparation

of

Porous

Polymers.

Chem.

Rev.

2012,

112,

3959-4015.

DOI: 10.1021/cr200440z (23)

Dawson, R.; cooper, A. I.; Adams, D. J. Nanoporous Organic Polymer Networks. Prog. Poly. Sci. 2012, 37, 530-563. DOI: 10.1016/j.progpolymsci.2011.09.002

(24)

Liu, X. M.; Xu, Y. H.; Jiang, D. L. Conjugated Microporous Polymers as Molecular Sensing Devices: Microporous Architecture Enables Rapid Response and Enhances Sensitivity in Fluorescence-On and Fluorescence-Off Sensing. J. Am. Chem. Soc. 2012, 134, 8738-8741. DOI: 10.1021/ja303448r

(25)

Zhu, Y. L.; Long, H.; Zhang, W. Imine-Linked Porous Polymer Frameworks with High Small Gas (H2, CO2, CH4, C2H2) Uptake and CO2/N2 Selectivity. Chem. Mater. 2013, 25, 1630-1635. DOI: 10.1021/cm400019f

(26)

Cai, S. –L.; Zhang, Y. –B.; Pun, A. B.; He, B.; Yang, J.; Toma, F. M.; Sharp, I. D.; Yaghi, O. M.; Fan, J.; Zheng, S. –R.; Zhang, W. –G.; Liu, Y. Tunable Electrical Conductivity in Oriented Thin Films of Tetrathiafulvalene-Based Covalent Organic Framework. Chem. Sci. 2014, 5, 4693-4700. DOI: 10.1039/C4SC02593H

(27)

Peng, Y.; Hu, Z.; Gao, Y.; Yuan, D.; Kang, Z.; Qian, Y.; Yan, N.; Zhao, D. Synthesis of a Sulfonated Two-Dimensional Covalent Organic Framework as an Efficient Solid Acid Catalyst for Biobased Chemical Conversion. ChemSusChem 2015, 8, 3208-3212. DOI: 10.1002/cssc.201500755

(28)

Li, Z.; Feng, X.; Zou, Y.; Zhang, Y.; Xia, H.; Liu, X.; Mu, Y. A 2D Azine-Linked


Page 19 of 36 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


Covalent Organic Framework for Gas Storage Applications. Chem. Commun. 2014, 50, 13825-13828. DOI: 10.1039/C4CC05665E (29)

Vyas, V. S.; Vishwakarma, M.; Moudrakovski, I.; Haase, F.; Savasci, G.; Ochsenfeld, C.; Spatz, J. P.; Lotsch, B. V. Exploiting Noncovalent Interactions in an Imine-Based Covalent Organic Framework for Quercetin Delivery. Adv. Mater. 2016, 28, 8749-8754. DOI: 10.1002/adma.201603006

(30)

Ding, S. –Y.; Dong, M.; Wang, Y. –W.; Chen, Y. –T.; Wang, H. –Z.; Su, C. –Y.; Wang, W. Thioether-Based Fluorescent Covalent Organic Framework for Selective Detection and Facile Removal of Mercury(II). J. Am. Chem. Soc. 2016, 138, 3031-3037. DOI: 10.1021/jacs.5b10754

(31)

Er, D.; Dong, L.; Shenoy, V. B. Mechanisms for Engineering Highly Anisotropic Conductivity in a Layered Covalent-Organic Framework. J. Phys. Chem. C 2016, 120, 174-178. DOI: 10.1021/acs.jpcc.5b11928

(32)

Ding, H.; Li, Y.; Hu, H.; Sun, Y.; Wang, J.; Wang, C.; Wang, C.; Zhang, G.; Wang, B.; Xu, W.; Zhang, D. A Tetrathiafulvalene-Based Electroactive Covalent Organic Framework. Chem. Eur. J. 2014, 20, 14614-14618. DOI: 10.1002/chem.201405330

(33)

Medina, D. D.; Rotter, J. M.; Hu, Y.; Dogru, M.; Werner, V.; Auras, F.; Markiewicz, J. T.; Knochel, P.; Bein, T.

Room Temperature Synthesis of Covalent-Organic

Framework Films through Vapor-Assisted Conversion. J. Am. Chem. Soc. 2015, 137, 1016-1019. DOI: 10.1021/ja510895m (34)

Wei, H.; Chai, S.; Hu, N.; Yang, Z.; Wei, L.; Wang, L. The Microwave-Assisted Solvothermal Synthesis of a Crystalline Two-Dimensional Covalent Organic Framework with High CO2 Capacity. Chem. Commun. 2015, 51, 12178-12181.



Page 20 of 36

DOI: 10.1039/C5CC04680G (35)

Yang, B.; Björk, J.; Lin, H.; Zhang, X.; Zhang, H.; Li, Y.; Fan, J.; Li, Q.; Chi, L. Synthesis of Surface Covalent Organic Frameworks via Dimerization and Cyclotrimerization of Acetyls. J. Am. Chem. Soc. 2015, 137, 4904-4907. DOI: 10.1021/jacs.5b00774

(36)

Modak, A.; Mondal, J.; Aswal, V. K.; Bhaumik, A. A New Periodic Mesoporous Organosilica Containing Diimine-Phloroglucinol, Pd(II)-Grafting and its Excellent Catalytic Activity and Trans-Selectivity In C-C Coupling Reactions. J. Mater. Chem. 2010, 20, 8099-8106. DOI: 10.1039/C0JM01180K

(37)

Gomes, R.; Bhanja, P.; Bhaumik, A. A Triazine-Based Covalent Organic Polymer for Efficient

CO2

Adsorption.

Chem.

Commun.

2015,

51,

10050-10053.

DOI: 10.1039/C5CC02147B (38)

Pachfule, P.; Kandmabeth, S.; Mallick, A.; Banerjee, R. Hollow Tubular Porous Covalent Organic Framework (COF) Nanostructures. Chem. Commun. 2015, 51, 1171711720. DOI: 10.1039/C5CC04130A

(39)

Kundu, S. K.; Bhaumik, A. Novel Nitrogen and Sulfur Rich Hyper-Cross-Linked Microporous Poly-Triazine-Thiophene Copolymer for Superior CO2 Capture. ACS Sustainable Chem. Eng. 2016, 4, 3697-3703. DOI: 10.1021/acssuschemeng.6b00262

(40)

Bhanja, P.; Bhunia, K.; Das, S. K.; Pradhan, D.; Kimura, R.; Hijikata, Y.; Irle, S.; Bhaumik, A. A New Triazine-Based Covalent Organic Framework for HighPerformance Capacitive Energy Storage. ChemSusChem 2017, 10, 921-929. DOI: 10.1002/cssc.201601571

(41)

Kandambeth, S.; Mallick, A.; Lukose, B.; Mane, M. V.; Heine, T.; Banerjee, R.


Page 21 of 36 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


Construction of Crystalline 2D Covalent Organic Frameworks with Remarkable Chemical (Acid/Base) Stability via a Combined Reversible and Irreversible Route. J. Am. Chem. Soc. 2012, 134, 19524-19527. DOI: 10.1021/ja308278w (42)

Soganci, T.; Kurtay, G.; Ak, M.; Gullu, M. Preparation of an EDOT-Based Polymer: Optoelectronic Properties and Electrochromic Device Application. RSC Adv. 2015, 5, 2630-2639. DOI: 10.1039/C4RA13060J

(43)

Wang, Y.; Masunaga, H.; Hikima, T.; Matsumoto, H.; Mori, T.; Michinobu, T. New Semiconducting Polymers Based on Benzobisthiadiazole Analogues: Tuning of Charge Polarity in Thin Film Transistors via Heteroatom Substitution. Macromolecules 2015, 48, 4012-4023. DOI: 10.1021/acs.macromol.5b00802

(44)

Chee, W. K.; Lim, H. N.; Harrison, I.; Chong, K. F.; Zainal, Z.; Ng, C. H.; Huang, N. M. Performance of Flexible and Binderless Polypyrrole/Graphene Oxide/Zinc Oxide Supercapacitor Electrode in a Symmetrical Two-Electrode Configuration. Electrochim. Acta 2015, 157, 88-94. DOI: 10.1016/j.electacta.2015.01.080

(45)

Li, Z.; Zhou, Z.; Yun, G.; Shi, K.; Lv, X.; Yang, B. High-Performance Solid-State Supercapacitors Based on Graphene-ZnO Hybrid Nanocomposites. Nanoscale Res. Lett. 2013, 8, 473. DOI: 10.1186/1556-276X-8-473

(46)

Biswas, S.; Drzal, L. T. Multi layered Nanoarchitecture of Graphene Nanosheets and Polypyrrole Nanowires for High Performance Supercapacitor Electrodes. Chem. Mater. 2010, 22, 5667-5671. DOI: 10.1021/cm101132g

(47)

Dubal, D. P.; Ayyad, O.; Ruiz, V.; Gomez-Romero, P. Hybrid Energy Storage: The Merging of Battery and Supercapacitor Chemistries. Chem. Soc. Rev. 2015, 44, 17771790. DOI: 10.1039/C4CS00266K



(48)

Page 22 of 36

Puthusseri, D.; Aravindan, V.; Madhavide, S.; Ogale, S. B. 3D Micro-Porous Conducting Carbon Beehive by Single Step Polymer Carbonization for High Performance Supercapacitors: The Magic of in situ Porogen Formation. Energy Environ. Sci. 2014, 7, 728-735. DOI: 10.1039/C3EE42551G

(49)

Tang, J. J.; Salunkhe, R. R.; Liu, J.; Torad, N. L.; Imura, M.; Furukawa, S.; Yamauchi, Y. Thermal Conversion of Core-Shell Metal-Org. Frameworks: A New Method for Selectively Functionalized Nanoporous Hybrid Carbon. J. Am. Chem. Soc. 2015, 137, 1572-1580. DOI: 10.1021/ja511539a

(50)

Hao, L.; Luo, B.; Li, X.; Jin, M.; Fang, Y.; Tang, Z.; Jia, Y.; Liang, M.; Thomas, A.; Yang, J.; Zhi, L. Terephthalonitrile-Derived Nitrogen-Rich Networks for High Performance

Supercapacitors.

Energy

Environ.

Sci.

5,

2012,

9747-9751.

DOI: 10.1039/C2EE22814A (51)

Ai, W.; Zhou, W.; Du, Z.; Du, Y.; Zhang, H.; Xie, L.; Yu, T.; Huang, W. Benzoxazole and

Benzimidazole

Supercapacitor

Heterocycle-Grafted

Electrodes.

J.

Mater.

Graphene Chem.

for

High-Performance

2012, 22,

23439-23446.

DOI: 10.1039/C2JM35234F (52)

Wickramaratne, N. P.; Xu, J.; Wang, M.; Zhu, L.; Dai, L.; Jaroniec, M. Nitrogen Enriched Porous Carbon Spheres: Attractive Materials for Supercapacitor Electrodes and CO2 Adsorption. Chem. Mater. 2014, 26, 2820-2828. DOI: 10.1021/cm5001895

(53)

Wu, S.; Chen, W.; Yan, L. Fabrication of a 3D Mno2/Graphene Hydrogel for HighPerformance Asymmetric Supercapacitors. J. Mater. Chem. A 2014, 2, 2765-2772. DOI: 10.1039/C3TA14387B

(54)

Xiang, C.; Li, M.; Zhi, M.; Manivannanc, A.; Wu, N. Reduced Graphene Oxide


Page 23 of 36 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


/Titanium Dioxide Composites for Supercapacitor Electrodes: Shape and Coupling Effects. J. Mater. Chem. 2012, 22, 19161-19167. DOI: 10.1039/C2JM33177B (55)

Mu, J.; Chen, B.; Guo, Z.; Zhang, M.; Zhang, Z.; Zhang, P.; Shao, C.; Liu, Y. Highly Dispersed Fe3O4 Nanosheets on One-Dimensional Carbon Nanofibers: Synthesis, Formation Mechanism, and Electrochemical Performance as Supercapacitor Electrode Materials. Nanoscale 2011, 3, 5034-5040. DOI: 10.1039/C1NR10972C

(56)

Wang, L.; Ji, H.; Wang, S.; Kong, L.; Jiang, X.; Yang, G. Preparation of Fe3O4 with High Specific Surface Area and Improved Capacitance as a Supercapacitor. Nanoscale 2013, 5, 3793-3799. DOI: 10.1039/C3NR00256J

(57)

Patra, B. C.; Khilari, S.; Satyanarayana, L.; Pradhan, D.; Bhaumik, A. A New Benzimidazole Based Covalent Organic Polymer Having High Energy Storage Capacity. Chem. Commun. 2016, 52, 7592-7595. DOI: 10.1039/C6CC02011A

(58)

Ganganboina, A. B.; Chowdhury, A. Dutta; Doong, R. A. New Avenue for Appendage of Graphene Quantum Dots on Halloysite Nanotubes as Anode Materials for High Performance Supercapacitors. ACS Sustainable Chem. Eng. 2017, 5, 4930-4940. DOI: 10.1021/acssuschemeng.7b00329

(59)

Du, X.; Wang, C.; Chen, M.; Jiao, Y.; Wang, J. Electrochemical Performances of Nanoparticle Fe3O4/Activated Carbon Supercapacitor Using KOH Electrolyte Solution. J. Phys. Chem. C 2009, 113, 2643-2646. DOI: 10.1021/jp8088269.



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FIGURES

Figure 1. Wide angle powder X-ray diffraction pattern of TPDA-1.


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Figure 2. The N2 sorption isotherms of TPDA-1, where filled and open circles indicate the adsorption and desorption isotherms, respectively. NLDFT pore size distribution plot is shown in the inset.



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Figure 3. The solid state 13C CP MAS NMR spectrum of TPDA-1. Polymeric network of TPDA-1 is shown in the inset.


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Figure 4. FTIR spectra of TPDA-1 (a), and TAPT-1 (b) and PDA (c) monomers.



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Figure 5. FE-SEM images of TPDA-1 at different magnifications (a and b).


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Figure 6. The HR-TEM images of TPDA-1 at different magnifications (a and b).



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Figure 7. Cyclic voltammograms of TDPA-1 at different scan rates in 1 M H2SO4 electrolyte.


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Figure 8. Specific capacitances of TPDA-1 at different scan rates in 1 M H2SO4 electrolyte.



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Figure 9. Galvanostatic charge-discharge plots (A) and specific capacitance at different current densities (B) for TPDA-1 electrode measured in 1 M H2SO4 electrolyte.


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Figure 10. Cyclic stability i.e. specific capacitance vs. cycle number (up to 1000 cycles) of TPDA-1 electrode as measured from Galvanostatic charge-discharge measurement at an applied current density of 5 A/g.



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Figure 11. Nyquist plot for TPDA-1 material in the frequency range of 100 KHz to 100 mHz in 1 M H2SO4 electrolyte.


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SCHEMES

Scheme 1. Schematic representation for the synthesis of the porous polymer TPDA-1 and its polymeric network.



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Table of Contents

A new porous polymer has been synthesized via solvothermal Schiff base condensation reaction of 2,4,6-trihydroxyisophthalaldehyde and 1,3,5-tris-(4-aminophenyl) triazine, and it showed excellent specific capacitance of 469.4 Fg-1, at 2 mV/s scan rate.


A New Porous Polymer for Highly Efficient Capacitive Energy Storage

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