@article { ISI:000321203900073, title = {1-Dimensional confinement of porous polyethylenedioxythiophene using carbon nanofibers as a solid template: an efficient charge storage material with improved capacitance retention and cycle stability}, journal = {RSC Advances}, volume = {3}, number = {29}, year = {2013}, month = {APR}, pages = {11877-11887}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Here, we report a highly conducting porous 1-dimensionally (1-D) confined nano hybrid of polyethylenedioxythiophene (PEDOT) using a cup-stacked hollow carbon nanofiber (CNF) as a solid template for potential charge storage applications. The unique features of the nano confinement involve significantly high porosity and conductivity with the establishment of the 1-D architecture. Since the tubular morphology of the CNF with its open tips provides facile routes for the electrolyte, the overall utilization of the active surface and conductivity increases the charge storage properties of PEDOT in the hybrid. The approach helped in achieving a high specific capacitance of 177 F g(-1) for 40\% PEDOT-CNF at a scan rate of 50 mV s(-1) and in retaining 130 F g(-1) even at 3000 mV s(-1) compared to 76 and 30 F g(-1) respectively given by pure PEDOT in 0.5 M H2SO4. The hybrid CP-40 shows a very high power density of 51 kW kg(-1) with an energy density of 4.7 Wh kg(-1). High capacitance retention is supported by the low charge transfer resistance and very low time constant (less than 0.5 s) values for the hybrid using impedance analysis. Phase angle calculations from a Bode plot also show an ideal capacitive nature with -90 degrees phase difference at 0.1 Hz for the hybrids. Apart from all these, the solid CNF backbone helps the hybrid material to display excellent cycle stability with \>98\% retention in capacitance over 4500 charge-discharge cycles compared to pristine PEDOT at a current density of 2 A g(-1).

}, issn = {2046-2069}, doi = {10.1039/c3ra40853a}, author = {Anothumakkool, Bihag and Bhange, Siddheshwar N. and Unni, SreeKuttan M. and Kurungot, Sreekumar} } @article { ISI:000329137400081, title = {Design of a high performance thin all-solid-state supercapacitor mimicking the active interface of its liquid-state counterpart}, journal = {ACS Applied Materials \& Interfaces}, volume = {5}, number = {24}, year = {2013}, month = {DEC}, pages = {13397-13404}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Here we report an all-solid-state supercapacitor (ASSP) which closely mimics the electrode-electrolyte interface of its liquid-state counterpart by impregnating polyaniline (PANO-coated carbon paper with polyvinyl alcohol-H2SO4 (PVA-H2SO4) gel/plasticized polymer electrolyte. The well penetrated PVA-H2SO4 network along the porous carbon matrix essentially enhanced the electrode-electrolyte interface of the resulting device with a very low equivalent series resistance (ESR) of 1 Omega/cm(2) and established an interfacial structure very similar to a liquid electrolyte. The designed interface of the device was confirmed by cross-sectional elemental mapping and scanning electron microscopy (SEM) images. The PANI in the device displayed a specific capacitance of 647 F/g with an areal capacitance of 1 F/cm(2) at 0.5 A/g and a capacitance retention of 62\% at 20 A/g. The above values are the highest among those reported for any solid-state-supercapacitor. The whole device, including the electrolyte, shows a capacitance of 12 F/g with a significantly low leakage current of 16 mu A(2). Apart from this, the device showed excellent stability for 10000 cycles with a coulombic efficiency of 100\%. Energy density of the PANI in the device is 14.3 Wh/kg.

}, keywords = {all-solid-state, cyclic voltametry, impedance analysis, polyaniline, polyvinyl alcohol, supercapacitor}, issn = {1944-8244}, doi = {10.1021/am404320e}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Bhange, Siddheshwar N. and Unni, SreeKuttan M. and Badiger, Manohar V. and Kurungot, Sreekumar} } @article { ISI:000325548600016, title = {Redox-mediated synthesis of functionalised graphene: a strategy towards 2D multifunctional electrocatalysts for energy conversion applications}, journal = {ChemPlusChem}, volume = {78}, number = {10}, year = {2013}, month = {OCT}, pages = {1296-1303}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A simple, one-step synthetic route for developing a two-dimensional multifunctional electrocatalyst is reported, by the functionalisation of graphene using oxidised ethylenedioxythiophene (O-EDOT). The mutually assisted redox reaction between graphene oxide (GO) and EDOT facilitates the reduction of GO to graphene with a concomitant deposition of O-EDOT on the surface of the graphene. The oxidised surface of GO catalyses the reaction without using an added reducing agent, so a controlled and uniform deposition of O-EDOT is ensured on the surface of graphene, which essentially prevents the restacking of the layers. UV/Visible, IR, Raman and X-ray photoelectron spectroscopy give valid evidence for the reduction and functionalisation of graphene sheets. The functional groups present on the surface of graphene are found to tune the physical and chemical properties of graphene. Consequently, the functionalised material displays enhanced electrocatalytic activity for the reduction of oxygen to water and I3- to I- relative to pristine graphene. These distinct property characteristics make the material a versatile cathode electrocatalyst for both alkaline anion-exchange membrane fuel cells and dye-sensitised solar cells.

}, keywords = {electrocatalysts, fuel cells, graphene, redox chemistry, solar cells}, issn = {2192-6506}, doi = {10.1002/cplu.201300153}, author = {Unni, SreeKuttan M. and Bhange, Siddheshwar N. and Anothumakkool, Bihag and Kurungot, Sreekumar} } @article {43040, title = {All-solid-state-supercapacitor and a process for the fabrication thereof}, number = {PCT/IN2014/000233}, year = {2014}, month = {OCT}, abstract = {

The present invention discloses. all-solid-state supercapacitor (ASSP) with enhanced electrode-electrolyte interface which gives highest very high specific capacitance, areal capacitance and shows very low internal resistance (ESR). The invention particularly discloses the fabrication of all-solid-state supercapacitor by intercalation of solid state polymer electrolyte inside the conducting porous substrate coated with a charge storage electrode material to achieve the desired effect.

}, author = {Kurungot, Sreekumar and Badiger, Manohar V. and Anothumakkool, Bihag and Torris, Arun} } @article { ISI:000337134500027, title = {Electrochemically grown nanoporous MnO2 nanowalls on a porous carbon substrate with enhanced capacitance through faster ionic and electrical mobility}, journal = {Chemical Communications}, volume = {50}, number = {54}, year = {2014}, month = {APR}, pages = {7188-7190}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report the deposition of uniform porous MnO2 nanowalls on a conducting carbon fiber substrate using a simple electrochemical method, which produces ordered nano-channels demarcated by the MnO2 walls for easy ion transport and a continuous electron path created by the carbon backbone. The system achieves a specific capacitance of 1149 F g(-1) and retains 565 F g(-1) even at dragging conditions as high as 100 A g(-1).

}, issn = {1359-7345}, doi = {10.1039/c4cc00927d}, author = {Anothumakkool, Bihag and Kurungot, Sreekumar} } @article { ISI:000336883000054, title = {Electrodeposited polyethylenedioxythiophene with infiltrated gel electrolyte interface: a close contest of an all-solid-state supercapacitor with its liquid-state counterpart}, journal = {Nanoscale}, volume = {6}, number = {11}, year = {2014}, month = {JUN}, pages = {5944-5952}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

We report the design of an all-solid-state supercapacitor, which has charge storage characteristics closely matching that of its liquid-state counterpart even under extreme temperature and humidity conditions. The prototype is made by electro-depositing polyethylenedioxythiophene (PEDOT) onto the individual carbon fibers of a porous carbon substrate followed by intercalating the matrix with polyvinyl alcohol-sulphuric acid (PVA-H2SO4) gel electrolyte. The electrodeposited layer of PEDOT maintained a flower-like growth pattern along the threads of each carbon fiber. This morphology and the alignment of PEDOT led to an enhanced surface area and electrical conductivity, and the pores in the system enabled effective intercalation of the polymer-gel electrolyte. Thus, the established electrode-electrolyte interface nearly mimics that of its counterpart based on the liquid electrolyte. Consequently, the solid device attained very low internal resistance (1.1 Omega cm(-2)) and a high specific capacitance (181 F g(-1)) for PEDOT at a discharge current density of 0.5 A g(-1). Even with a high areal capacitance of 836 mF cm(-2) and volumetric capacitance of 28 F cm(-3), the solid device retained a mass-specific capacitance of 111 F g(-1) for PEDOT. This is in close agreement with the value displayed by the corresponding liquid-state system (112 F g(-1)), which was fabricated by replacing the gel electrolyte with 0.5 M H2SO4. The device also showed excellent charge-discharge stability for 12 000 cycles at 5 A g(-1). The performance of the device was consistent even under wide-ranging humidity (30-80\%) and temperature (-10 to 80 degrees C) conditions. Finally, a device fabricated by increasing the electrode area four times was used to light an LED, which validated the scalability of the process.

}, issn = {2040-3364}, doi = {10.1039/c4nr00659c}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Bhange, Siddheshwar N. and Badiger, Manohar V. and Kurungot, Sreekumar} } @article { ISI:000340520500055, title = {Enhanced catalytic activity of polyethylenedioxythiophene towards tri-iodide reduction in DSSCs via 1-dimensional alignment using hollow carbon nanofibers}, journal = {Nanoscale}, volume = {6}, number = {17}, year = {2014}, month = {JUL}, pages = {10332-10339}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Here, we report a highly conducting 1-dimensionally (1-D) aligned polyethylenedioxythiophene (PEDOT) along the inner and outer surfaces of a hollow carbon nanofiber (CNF) and its application as a counter electrode in a dye sensitized solar cell (DSSC). The hybrid material (CP-25) displays a conversion efficiency of 7.16\% compared to 7.30\% for the standard Pt counter electrode, 4.48\% for bulk PEDOT and 5.56\% for CNF. The enhanced conversion efficiency of CP-25 is attributed to the accomplishment of high conductivity and surface area of PEDOT through the 1-D alignment compared to its bulk counterpart. Reduced charge transfer resistance and high conductivity of CP-25 could be proven by cyclic voltammetry, impedance analysis and Tafel experiments. Further, through a long-term stability test involving efficiency profiling for 20 days, it is observed that CP-25 possesses excellent durability compared to the bulk PEDOT.

}, issn = {2040-3364}, doi = {10.1039/c4nr00717d}, author = {Anothumakkool, Bihag and Game, Onkar S. and Bhange, Siddheshwar N. and Kumari, Tanya and Ogale, Satishchandra B. and Kurungot, Sreekumar} } @article {46360, title = {From waste paper basket to solid state and Li-HEC ultracapacitor electrodes: a value added journey for shredded office paper}, journal = {Small}, volume = {10}, year = {2014}, month = {NOV}, pages = {4395-4402}, type = {Article}, abstract = {

Hydrothermal processing followed by controlled pyrolysis of used white office paper (a globally collectable shredded paper waste) are performed to obtain high surface area carbon with hierarchical pore size distribution. The BET specific surface area of such carbon is 2341 m 2 g(-1). The interconnected macroporous structure along with the concurrent presence of mesopores and micropores makes the material ideal for ultracapacitor application. Such waste paper derived carbon (WPC) shows remarkable performance in all solid-state supercapacitor fabricated with ionic liquid-polymer gel electrolyte. At room temperature, the material exhibits a power density of 19 000 W kg(-1) with an energy capability of 31 Wh kg(-1). The Li-ion electrochemical capacitor constructed using WPC as cathode also shows an excellent energy storage capacity of 61 Wh kg(-1)

}, issn = {1613-6810}, doi = {10.1002/smll.201401041}, author = {Puthusseri, Dhanya and Aravindan, Vanchiappan and Anothumakkool, Bihag and Kurungot, Sreekumar and Madhavi, Srinivasan and Ogale, Satishchandra} } @article {46395, title = {Post-synthetically modified porous covalent framework (PCF) for high proton conduction}, journal = {Acta Crystallographica A-Foundation and Advances}, volume = {70}, year = {2014}, month = {MAY}, pages = {C1156}, type = {Meeting Abstract}, keywords = {Porous Covalent Framework, Post-synthetic Modification, proton conduction}, issn = {2053-2733}, author = {Samanta, Partha and Desai, Aamod and Anothumakkool, Bihag and Shirolkar, Mandar and Karmakar, Avishek and Kurungot, Sreekumar and Ghosh, Sujit} } @article { ISI:000353177000029, title = {3D polyaniline porous layer anchored pillared graphene sheets: enhanced interface joined with high conductivity for better charge storage applications}, journal = {ACS Applied Materials \& Interfaces}, volume = {7}, number = {14}, year = {2015}, month = {APR}, pages = {7661-7669}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Here, we report synthesis of a 3-dimensional (3D) porous polyaniline (PANI) anchored on pillared graphene (G-PANI-PA) as an efficient charge storage material for supercapacitor applications. Benzoic acid (BA) anchored graphene, having spatially separated graphene layers (G-Bz-COOH), was used as a structure controlling support whereas 3D PANI growth has been achieved by a simple chemical oxidation of aniline in the presence of phytic acid (PA). The BA groups on G-Bz-COOH play a critical role in preventing the restacking of graphene to achieve a high surface area of 472 m(2)/g compared to reduced graphene oxide (RGO, 290 m(2)/g). The carboxylic acid (-COOH) group controls the rate of polymerization to achieve a compact polymer structure with micropores whereas the chelating nature of PA plays a crucial role to achieve the 3D growth pattern of PANI. This type of controlled interplay helps G-PANI-PA to achieve a high conductivity of 3.74 S/cm all the while maintaining a high surface area of 330 m(2)/g compared to PANI-PA (0.4 S/cm and 60 m(2)/g). G-PANI-PA thus conceives the characteristics required for facile charge mobility during fast charge-discharge cycles, which results in a high specific capacitance of 652 F/g for the composite. Owing to the high surface area along with high conductivity, G-PANI-PA displays a stable specific capacitance of 547 F/g even with a high mass loading of 3 mg/cm(2), an enhanced areal capacitance of 1.52 F/cm(2), and a volumetric capacitance of 122 F/cm(3). The reduced charge-transfer resistance (RCT) of 0.67 O displayed by G-PANI-PA compared to pure PANI (0.79 O) stands out as valid evidence of the improved charge mobility achieved by the system by growing the 3D PANI layer along the spatially separated layers of the graphene sheets. The low RCT helps the system to display capacitance retention as high as 65\% even under a high current dragging condition of 10 A/g. High charge/discharge rates and good cycling stability are the other highlights of the supercapacitor system derived from this composite material.

}, keywords = {durability, ionic accessibility, phytic acid, pillaring, polyaniline, restacking}, issn = {1944-8244}, doi = {10.1021/acsami.5b00504}, author = {Sekar, Pandiaraj and Anothumakkool, Bihag and Kurungot, Sreekumar} } @article { ISI:000362291300048, title = {Architecturally designed Pt-MoS2 and Pt-graphene composites for electrocatalytic methanol oxidation}, journal = {Physical Chemistry Chemical Physics}, volume = {17}, number = {39}, year = {2015}, month = {SEP}, pages = {26101-26110}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Thin films consisting of platinum nanoparticles (Pt NPs) with uniform size and distribution have been successfully prepared at a liquid-liquid interface. Apart from the usual substrates like glass, Si etc. the films were also deposited on the surfaces of MoS2 thin films and graphene nanosheets (GNS) respectively, by using a layer-by-layer (LbL) deposition technique to form Pt-MoS2 and Pt-GNS composites. The loading concentration of Pt NPs on MoS2 and GNS can be adjusted by selecting the number and sequence of the component layers during LbL deposition. The Pt thin films, Pt-MoS2 and Pt-GNS nanocomposite thin films are characterized using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). TEM results of the composites show that Pt NPs with sizes in the range of 1 to 3 nm are uniformly dispersed on the MoS2/GNS surface. The catalytic activities of Pt and Pt-composites for the reaction of methanol oxidation are studied using cyclic voltammetry and chronoamperometry. Electrochemical studies reveal that both the Pt-MoS2 and Pt-GNS nanocomposites show excellent electrocatalytic activity towards methanol oxidation. Pt-MoS2 and Pt-GNS nanocomposite electrodes show excellent stability for reuse of the catalyst. A probable mechanism of catalysis has been discussed. We propose that the similar architecture reported here would be promising for the synthesis of high performance catalysts for fuel cells, gas phase reactions, and other applications such as sensors.

}, issn = {1463-9076}, doi = {10.1039/c5cp04141d}, author = {Patit, Sagar H. and Anothumakkool, Bihag and Sathaye, Shivaram D. and Patil, Kashinath R.} } @article { ISI:000355638100042, title = {Coherent fusion of water array and protonated amine in a metal-sulfate-based coordination polymer for proton conduction}, journal = {Inorganic Chemistry}, volume = {54}, number = {11}, year = {2015}, month = {JUN}, pages = {5366-5371}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A new function of metal-sulfate-based co-ordination polymer (CP) for proton,conduction Was investigated through rational integration of a continuous water array and protonated amine in the coordination space of the CP. The H-bonded arrays of watet molecules along with nitrogen-rich aromatic cation (protonated melamine) facilitate proton conduction in the compound under humid conditions. Although several reports of metal-oxalate/phosphate-based CPs showing proton conduction are known, this is the first designed synthesis of a metal sulfate-based CP bearing-Water arrays functioning as a solid-state proton conductor:

}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.5b00416}, author = {Manna, Biplab and Anothumakkool, Bihag and Desai, Aamod V. and Samanta, Partha and Kurungot, Sreekumar and Ghosh, Sujit K.} } @article { ISI:000348366500030, title = {Tuning of multiple luminescence outputs and white-light emission from a single gelator molecule through an ESIPT coupled AIEE process}, journal = {Chemical Communications}, volume = {51}, number = {11}, year = {2015}, month = {DEC}, pages = {2130-2133}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A unique example of an ESIPT coupled AIEE process, associated with a single molecule (1), is utilized for generating multiple luminescent colors (blue-green-white-yellow). The J-aggregated state of 1 forms a luminescent gel in THF and this luminescent property is retained even in the solid state.

}, issn = {1359-7345}, doi = {10.1039/c4cc09211b}, author = {Maity, Arunava and Ali, Firoj and Agarwalla, Hridesh and Anothumakkool, Bihag and Das, Amitava} } @article {45650, title = {1D alignment of PEDOT in a buckypaper for high-performance solid supercapacitors}, journal = {Chemelectrochem}, volume = {3}, year = {2016}, month = {SEP}, pages = {1329-1336}, type = {Article}, abstract = {

A flexible solid-state supercapacitor is prepared from carbon nanotube (CNT)-based buckypaper after forming a thin layer of polyethylenedioxythiophene (PEDOT) on the surface of the CNTs in the paper. A highly conducting PEDOT phase is obtained by interfacial polymerization, in which polymerization is confined at the interface of two immiscible liquids. The hydrophilic interaction between the functionalized CNTs and the oxidizing agent (iron perchlorate, Fe(ClO4)(3)), which is located in the aqueous phase, and the restricted interaction of the oxidizing agent with the EDOT monomer in the organic layer at the immiscible interface play a vital role in establishing a uniform and aggregate-free growth pattern of PEDOT on CNT. By carefully optimizing the amount of polymer in the paper, an electrode with a sheet resistance of 3.4(-1) and equivalent series resistance of 0.95 can be prepared. A thin and flexible solid-state supercapacitor device with an overall thickness of 210m is made by using this paper as the electrodes and poly(vinyl alcohol)/lithium chloride as the gel electrolyte. The power density and energy density of the electrode are 9.94Wcm(-3) and 8.85mWhcm(-3), respectively. The device also delivers a high volumetric capacitance of 18Fcm(-3) and areal capacitance of 354mFcm(-2). The demonstrated strategy is scalable and hence the process can be conveniently applied to prepare large-area PEDOT-modified buckypapers in a short time.

}, keywords = {Carbon, Energy storage, nanotubes, polymerization, Supercapacitors}, issn = {2196-0216}, doi = {10.1002/celc.201600229}, author = {Soni, Roby and Anothumakkool, Bihag and Kurungot, Sreekumar} } @article { ISI:000378715600028, title = {High hydroxide conductivity in a chemically stable crystalline metal-organic framework containing a water-hydroxide supramolecular chain}, journal = {Chemical Communications}, volume = {52}, number = {54}, year = {2016}, month = {JUN}, pages = {8459-8462}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A chemically stable cationic MOF encapsulating an in situ formed water-hydroxide supramolecular anionic chain is realized for high hydroxide (OH-) ion conductivity in the solid-state (Type A). High OH- ion conductivity and low activation energy of the MOF demonstrate the advantage of the in situ incorporation of OH- ions to achieve efficient OH- ion conduction in the solid-state.

}, issn = {1359-7345}, doi = {10.1039/c6cc04436k}, author = {Nagarkar, Sanjog S. and Anothumakkool, Bihag and Desai, Aamod V. and Shirolkar, Mandar M. and Kurungot, Sreekumar and Ghosh, Sujit K.} } @article { ISI:000368651100021, title = {High-Performance flexible solid-state supercapacitor with an extended nanoregime interface through in situ polymer electrolyte generation}, journal = {ACS Applied Materials \& Interfaces}, volume = {8}, number = {2}, year = {2016}, month = {JAN}, pages = {1233-1241}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{Here, we report an efficient strategy by which a significantly enhanced electrodeelectrolyte interface in an electrode for supercapacitor application could be accomplished by allowing in situ polymer gel electrolyte generation inside the nanopores of the electrodes. This unique and highly efficient strategy could be conceived by judiciously maintaining ultraviolet-triggered polymerization of a monomer mixture in the presence of a high-surface-area porous carbon. The method is very simple and scalable, and a prototype, flexible solid-state supercapacitor could even be demonstrated in an encapsulation-free condition by using the commercial-grade electrodes (thickness = 150 mu m

}, keywords = {cyclic voltametry, impedance analysis, in situ polymer generation, interface, polymer electrolyte, supercapacitor}, issn = {1944-8244}, doi = {10.1021/acsami.5b09677}, author = {Anothumakkool, Bihag and Torris, Arun A. T. and Veeliyath, Sajna and Vijayakumar, Vidyanand and Badiger, Manohar V. and Kurungot, Sreekumar} } @article {45652, title = {Hydrogen-bonded organic frameworks (HOFs): a new class of porous crystalline proton-conducting materials}, journal = {Angewandte Chemie-International Edition}, volume = {55}, year = {2016}, month = {AUG }, pages = {10667-10671}, type = {Article}, abstract = {

Two porous hydrogen-bonded organic frameworks (HOFs) based on arene sulfonates and guanidinium ions are reported. As a result of the presence of ionic backbones appended with protonic source, the compounds exhibit ultra-high proton conduction values (sigma) 0.75x 10(-2)Scm(-1) and 1.8x10(-2)Scm(-1) under humidified conditions. Also, they have very low activation energy values and the highest proton conductivity at ambient conditions (low humidity and at moderate temperature) among porous crystalline materials, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs). These values are not only comparable to the conventionally used proton exchange membranes, such as Nafion used in fuel cell technologies, but is also the highest value reported in organic-based porous architectures. Notably, this report inaugurates the usage of crystalline hydrogen-bonded porous organic frameworks as solid-state proton conducting materials.

}, keywords = {guanidinium, hydrogen-bonded organic frameworks, porous crystalline frameworks, proton conduction, sulfonates}, issn = {1433-7851}, doi = {10.1002/anie.201604534}, author = {Karmakar, Avishek and Illathvalappil, Rajith and Anothumakkool, Bihag and Sen, Arunabha and Samanta, Partha and Desai, Aamod V. and Kurungot, Sreekumar and Ghosh, Sujit K.} } @article { ISI:000368563000067, title = {Pt- and TCO-free flexible cathode for DSSC from highly conducting and flexible PEDOT paper prepared via in situ interfacial polymerization}, journal = {ACS Applied Materials \& Interfaces}, volume = {8}, number = {1}, year = {2016}, month = {JAN}, pages = {553-562}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Here, we report the preparation of a flexible, free-standing, Pt- and TCO-free counter electrode in dye-sensitized solar cell (DSSC)-derived from polyethylenedioxythiophene (PEDOT)-impregnated cellulose paper. The synthetic strategy of making the thin flexible PEDOT paper is simple and scalable, which can be achieved via in situ polymerization all through a roll coating technique. The very low sheet resistance (4 Omega/square) obtained from a film of 40 mu m thick PEDOT paper (PEDOT-p-5) is found to be superior to the conventional fluorine-doped tin oxide (FTO) substrate. The high conductivity (357 S/cm) displayed by PEDOT-p-5 is observed to be stable under ambient conditions as well as flexible and bending conditions. With all of these features in place, we could develop an efficient Pt- and TCO-free flexible counter electrode from PEDOT-p-5 for DSSC applications. The catalytic activity toward the tri-iodide reduction of the flexible electrode is analyzed by adopting various electrochemical methodologies. PEDOT-p-5 is found to display higher exchange current density (7.12 mA/cm(2)) and low charge transfer resistance (4.6 Omega) compared to the benchmark Pt-coated FTO glass (2.40 mA/cm(2) and 9.4 Omega, respectively). Further, a DSSC fabricated using PEDOT-p-5 as the counter electrode displays a comparable efficiency of 6.1\% relative to 6.9\% delivered by a system based on Pt/FTO as the counter electrode.

}, keywords = {counter electrode, dye-sensitized solar cell, flexible and thin devices, impedance analysis, interfacial polymerization, polyethylenedioxythiophene}, issn = {1944-8244}, doi = {10.1021/acsami.5b09579}, author = {Anothumakkool, Bihag and Agrawal, Ishita and Bhange, Siddheshwar N. and Soni, Roby and Game, Onkar S. and Ogale, Satishchandra B. and Kurungot, Sreekumar} } @article { ISI:000380045400014, title = {Unravelling the mechanism of electrochemical degradation of PANI in supercapacitors: achieving a feasible solution}, journal = {Chemelectrochem}, volume = {3}, number = {6}, year = {2016}, month = {JUN}, pages = {933-942}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Herein, we have investigated the mode of electrochemical degradation of polyaniline (PANI) when it was utilized as electrodes for supercapacitors. The PANI-based electrodes in supercapacitor devices were biased at a constant potential of 0.80 V, and the performance characteristics and property changes were carefully investigated as a function of the difference in the polarity of the electrodes. Subsequent to this, the analysis of the individual electrodes [positive (POS-PANI) and negative (NEG-PANI)] shows that the degradation mainly occurs at POS-PANI in comparison to NEG-PANI. Moreover, NEG-PANI retains a maximum capacitance of 510 Fg(-1), with a low charge-transfer resistance (R-CT) of 1.84 Omega and similar redox behavior in comparison to the fresh PANI (f-PANI). In contrast to this case, POS-PANI shows significant loss in capacitance (250 Fg(-1)) and increase in R-CT (3.5 Omega) with a disappearance of the characteristic redox behavior normally displayed by PANI. Furthermore, the drastic drop in the electrical conductivity for POS-PANI (1.2 Scm(-1)) compared to f-PANI (3.4 Scm(-1) and NEG-PANI (2.4 Scm(-1)) shows that the degradation of PANI occurs mainly at the anode (POS-PANI) and, thus, contributes to reduce the net performance of the cell. Hence, to ensure this potential-induced degradation of PANI in supercapacitors and also to promote the system stability, we made an asymmetric supercapacitor (ASC) by keeping PANI as a negative electrode and using carbon as a positive electrode. The derived system is found to display stable capacitance behavior before and after the potential application, in contrast to the ASC fabricated by using conventional method, that is, by keeping PANI as the positive electrode and carbon as the negative electrode. Furthermore, the durability analysis of the prototype solid-state ASC shows an enhanced durability of 27000 cycles with excellent columbic efficiency. The findings of the present study will be helpful in the development of highly stable supercapacitors and other similar energy systems when a material like PANI should be utilized for the electrode applications.

}, keywords = {asymmetric supercapacitors, cycle stability, electrochemical degradation, polarization, redox chemistry}, issn = {2196-0216}, doi = {10.1002/celc.201500502}, author = {Sekar, Pandiaraj and Anothumakkool, Bihag and Vijayakumar, Vidyanand and Lohgaonkar, Apurva and Kurungot, Sreekumar} } @article {43846, title = {Enhanced proton conduction by post-synthetic covalent modification in a porous covalent framework}, journal = {Journal of Materials Chemistry A}, volume = {5}, year = {2017}, month = {JUL}, pages = {13659-13664}, type = {Article}, abstract = {A highly chemically stable porous covalent framework (PCF-1) based on ether linkages has been synthesized, which exhibits no loss up to similar to 500 degrees C along with retention of integrity under acidic, basic and oxidative reagent conditions. Owing to its thermal and chemical stability, post-synthetic covalent modification was executed for the introduction of pendant sulphonic acid (-SO3H) groups. The covalently modified compound (PCF-1-SO3H) presents a remarkably high conductivity (ca. 0.026 S cm(-1)), with an similar to 130 fold enhancement in proton conductivity over the parent compound. This value is comparable with those of commercially used Nafion-based proton conducting materials and stands as the highest known value in the regime of post-synthetically modified porous organic frameworks. It is noteworthy to mention that PCF-1 is stable in both acidic and alkaline media, which is not commonly observed for most of the porous materials trialed as proton conducting materials, including metal organic frameworks.}, doi = {10.1039/c7ta00964j}, author = {Samanta, Partha and Desai, Aamod V. and Anothumakkool, Bihag and Shirolkar, Mandar M. and Karmakar, Avishek and Kurungot, Sreekumar and Ghosh, Sujit K.} } @article {46898, title = {Nafion lonomer-based single component electrolytes for aqueous Zn/MnO2 batteries with long cycle life}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {8}, year = {2020}, month = {APR }, pages = {5040-5049}, type = {Article}, abstract = {

Recently, aqueous rechargeable Zn/MnO2 batteries are emerging as promising energy storage aids owing to their improved safety, low cost of fabrication, and high energy density. However, the rapid decay of capacity during extended charge- discharge cycles hinders the prospect of this technology beyond lab-scale. In the conventional Zn/MnO2 cell, additives such as Mn2+ have been used to tackle the stability issue. Here, we demonstrate that cycling performance of the Zn/MnO2 cell can be improved substantially by using Nafion ionomer as the separator in combination with zinc-ion conducting electrolytes. The Nafion ionomer-based Zn/MnO2 cells do not require any Mn{\textquoteright} additive in the electrolyte and hence termed as {\textquoteleft}{\textquoteleft}single component{\textquoteright}{\textquoteright} electrolytes. The postmortem study of the post-cycled electrodes reveals that the structural evolution of both the anode and cathode in various electrolytes (1 M Zn(CF3SO3)(2), 1 M ZnSO4 center dot 7H(2)O, and 3 M ZnSO4 center dot 7H(2)O) during prolonged cycling significantly influences the cycle life of the respective cells. Optimizing the Nafion ionomer membrane with a suitable electrolyte could render the desired combination of high capacity and high cycle life for a Zn/MnO2 cell.

}, keywords = {aqueous Zn-ion batteries, Cycling stability, dendrite suppression, Electrodeposition, MnO2, Nafion ionomer separator, single component electrolyte}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.9b06798}, author = {Ghosh, Meena and Vijayakumar, Vidyanand and Anothumakkool, Bihag and Kurungot, Sreekumar} } @article {47432, title = {In situ polymerization process: an essential design tool for lithium polymer batteries dagger}, journal = {Energy \& Environmental Science}, volume = {14}, year = {2021}, month = {MAY }, pages = {2708-2788}, type = {Review}, abstract = {

Polymer electrolytes (PEs), a type of solid-state electrolytes (SSEs), have been in contention for nearly half a century to replace organic liquid electrolytes (LEs) that are used in state-of-the-art lithium-ion batteries (LIBs). They are envisaged to accelerate the industrial-scale production of safe, energy-dense, flexible, and thin lithium polymer batteries (LPBs). LPBs are expected to be widely employed for electric propulsion and other futuristic applications, such as flexible electronics and the Internet of Things (IoT). Even though several polymer architectures and chemistries have been attempted so far, PEs that can outperform LEs remain a real challenge. Apart from inadequate Li+-ion transport properties, challenges concerning the integration of PEs and the engineering of compatible, robust, and durable interfaces and interphases at both the electrodes of LPBs must be appropriately addressed. Recently, the in situ polymerization process has been widely employed as a robust fabrication tool for surpassing the intricacies related to the integration of PEs in LPBs. Hence, in this review, we focus on the in situ polymerization processes that employ various polymerization methods (e.g., free-radical polymerization, ionic polymerization, electropolymerization, condensation polymerization, etc.), functional monomers and oligomers (e.g., acrylate, methacrylate, allyl and vinyl ethers, epoxides, etc.), and PE integration strategies for the fabrication of lithium (ion and metal) polymer batteries (LIPBs and LMPBs). Additionally, this review also evaluates the approaches that have been developed until now to implement the in situ processing of LPBs from large-sized pouch cells to flexible-/printable-batteries and even microbatteries.

}, issn = {1754-5692}, doi = {10.1039/d0ee03527k, Early Access Date = FEB 2021}, author = {Vijayakumar, Vidyanand and Anothumakkool, Bihag and Kurungot, Sreekumar and Winter, Martin and Nair, Jijeesh Ravi} }