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Bhagavatula Y.S.,Center for Fuel Cell Technology of India | Bhagavatula M.T.,Aurora College | Dhathathreyan K.S.,Center for Fuel Cell Technology of India
International Journal of Energy Research | Year: 2012

Investigations on using artificial neural networks to predict the performance of single proton exchange membrane fuel cell has been carried out. Two sets of polarization data obtained at different temperatures and flow rates are used to create and simulate the network. Cell temperature, humidification temperatures, H 2/air flow rates and current density have been used as inputs, and voltage is used as observed (output) value to train and simulate the network. This nonlinear data are batch trained, and artificial neural network has been constructed using feed forward backpropagation algorithm. Performance of the training has been improved by increasing the number of neurons to reduce the error. Simulation results are in agreement with experimental data, and the corresponding networks are used to predict the polarization behavior for unknown inputs. © 2011 John Wiley & Sons, Ltd.


Hamid N.A.,University of Duisburg - Essen | Wennig S.,Center for Fuel Cell Technology of India | Hardt S.,University of Duisburg - Essen | Heinzel A.,Center for Fuel Cell Technology of India | And 4 more authors.
Journal of Power Sources | Year: 2012

Olivine, LiFePO 4 is a promising cathode material for lithium-ion batteries due to its low cost, environmental acceptability and high stability. Its low electric conductivity prevented it for a long time from being used in large-scale applications. Decreasing its particle size along with carbon coating significantly improves electronic conductivity and lithium diffusion. With respect to the controlled formation of very small particles with large specific surface, gas-phase synthesis opens an economic and flexible route towards high-quality battery materials. Amorphous FePO 4 was synthesized as precursor material for LiFePO 4 by flame spray pyrolysis of a solution of iron acetylacetonate and tributyl phosphate in toluene. The pristine FePO 4 with a specific surface from 126-218 m 2 g -1 was post-processed to LiFePO 4/C composite material via a solid-state reaction using Li 2CO 3 and glucose. The final olivine LiFePO 4/C particles still showed a large specific surface of 24 m 2 g -1 and were characterized using X-ray diffraction (XRD), electron microscopy, X-ray photoelectron spectrocopy (XPS) and elemental analysis. Electrochemical investigations of the final LiFePO 4/C composites show reversible capacities of more than 145 mAh g -1 (about 115 mAh g -1 with respect to the total coating mass). The material supports high drain rates at 16 C while delivering 40 mAh g -1 and causes excellent cycle stability. © 2012 Elsevier B.V.


Samrot A.V.,Sathyabama University | Senthilkumar P.,Sathyabama University | Pavankumar K.,Sathyabama University | Akilandeswari G.C.,Sathyabama University | And 2 more authors.
International Journal of Hydrogen Energy | Year: 2010

We have investigated a Enterobacter cloacae SU-1, bacteria for mediator less microbial fuel cell with different carbon sources and is found to be more effective as the microorganism is able to transfer electrons directly (exo-electrogenic organism) via the cytochromes or the ubiquinone. These carriers of electrons are in form of stable reversible redox couples, not biologically degraded and not toxic to cell. The major advantage of mediator less microbial fuel cells emphasize that additives in the anolyte is not compatible with the purpose of water purification. The anode chamber with the bacteria is maintained under anaerobic conditions so that the bacteria will undergo anaerobic biochemical pathways like Glycolysis, TCA cycle, Electron Transport Chain (ETC) where electrons and protons are released. Here protons are released in TCA cycle and whereas electrons are released from ETC. The mediator less microbial fuel cell delivered an open circuit potential (OCP) of 0.93 V and power of 3 mW/sq cm. During power generation from the microbes, there was a drop in coulombic efficiency in terms of fluctuations during drawing power, as the carbon source is being utilized for the cell growth. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.


Jha N.,Nano Functional Materials Technology Center | Jafri R.I.,Nano Functional Materials Technology Center | Rajalakshmi N.,Center for Fuel Cell Technology of India | Ramaprabhu S.,Nano Functional Materials Technology Center
International Journal of Hydrogen Energy | Year: 2011

Nanostructured PtRu and Pt dispersed functionalized graphene-functionalized multi walled carbon nanotubes (PtRu/(f-G-f-MWNT)), (Pt/(f-G-f-MWNT)) nanocomposites have been prepared. Electrochemical studies have been performed for the methanol oxidation using cyclic voltammetry (CV) and chronoamperometry technique. Full cell measurements have been performed using PtRu nanoparticles dispersed on the mixture of functionalized graphene (f-G) and functionalized multi walled carbon nanotubes (f-MWNT) in different ratios as anode electrocatalyst for methanol oxidation and Pt/f-MWNT as cathode catalyst for oxygen reduction reaction in direct methanol fuel cell (DMFC). In addition, full cell measurements have been performed with PtRu/(50 wt% f-MWNT + 50 wt% f-G) and Pt/(50 wt% f-MWNT + 50 wt% f-G) as anode and cathode electrocatalyst respectively. With PtRu/(50 wt% f-MWNT + 50 wt% f-G) as anode electrocatalyst, a high power density of about 40 mW/cm2 has been obtained, in accordance with cyclic voltammetry studies. Further enhancement in the power density of about 68 mW/cm2 has been observed with PtRu/(50 wt% f-MWNT + 50 wt% f-G) and Pt/(50 wt% f-MWNT + 50 wt% f-G) as electrocatalyst at anode and cathode respectively. These results have been discussed based on the change in the morphology of the f-G sheets due to the addition of f-MWNT. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Sarada B.Y.,Center for Fuel Cell Technology of India | Dhathathreyan K.S.,Center for Fuel Cell Technology of India | Rama Krishna M.,International Advanced Research Center for Powder Metallurgy And New Materials
International Journal of Hydrogen Energy | Year: 2011

Oxygen Reduction Reaction (ORR) kinetics is known to be one of the major bottle necks in PEM Fuel Cell performance. Several attempts are being made to enhance the ORR. Inspite of several attempts Pt in the vicinity of high surface area oxide catalysts seems to be the best choice although some alloy catalyst have shown good performance in half cell studies and single cell studies. We are investigating methods to improve the performance of PEM fuel cell especially in low air flow conditions which is the condition that will arise in surge power requirements. We have found that oxygen reduction reaction (ORR) performance of Pt/C can be increased in the presence of cerium-zirconium oxides especially Ce0.8Zr0.2O2 (CZO) in the cathode catalyst layer. Ce0.8Zr0.2O2 was prepared by co-precipitation method and the formation is confirmed by the XRD results. An XPS study of Ce 3d emission spectra dominated by atomic multiplet effects in core level spectroscopy of Ce0.8Zr0.2O2-Pt/C are studied from which the possible oxidation states of Ce on Ce 0.8Zr0.2O2-Pt/C surface are examined. The ORR improvement in the CZO added electrodes have been studied using chronoammperometry and fuel cell testing. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Jafri R.I.,Center for Fuel Cell Technology of India | Rajalakshmi N.,Center for Fuel Cell Technology of India | Dhathathreyan K.S.,Center for Fuel Cell Technology of India | Ramaprabhu S.,Indian Institute of Technology Madras
International Journal of Hydrogen Energy | Year: 2015

Nitrogen doped graphene has been synthesized using hydrothermal method and thermal solid state method with ammonia and melamine as nitrogen sources respectively. Platinum nanoparticles have been dispersed over these support materials using polyol method and these Pt loaded nitrogen doped graphene samples have been studied as electrocatalyst for oxygen reduction reaction (ORR) in a proton exchange membrane fuel cell and for methanol oxidation reaction (MOR). Also, the role of multiwalled carbon nanotubes as a spacer which avoids face to face agglomeration of graphene sheets has also been studied for both the samples. The morphology and structure of the graphene based powder samples have been studied using X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Half cell and full cell measurements have been performed on the samples for ORR and MOR. With the use of functionalized multiwalled carbon nanotubes, a maximum power density of 704 mW cm-2 and 650 mW cm-2 has been obtained with Pt dispersed nitrogen doped graphenes prepared by hydrothermal and thermal solid state methods respectively. The results have been compared with commercial Pt/C catalyst. © 2015 Hydrogen Energy Publications, LLC.


Subramaniam C.K.,Vellore Institute of Technology | Subramaniam C.K.,Center for Fuel Cell Technology of India
ECS Transactions | Year: 2010

Various carbon-carbon EDLCs were assembled with ionic polymers of perfluorosulphonic acid polymer in the H+, Na+ and K + forms, composites of polytetrafluoro ethylene (PTFE) and perfluorosulphonic acid, PVA-KOH, sulphonated PEEK and PVdF. The surface area of the carbon used in these EDLCs is 260 m2/gm. CV, EIS and discharge profiles were used for characterization. The working voltage of these EDLCs was 2V. The specific capacitance was found to be 20 F/g, 40 F/g and 55 F/g for the perflurosulphonic acid electrolyte in H+, Na+ and K +, respectively. A specific capacitance of 16 F/g was obtained for the EDLC with the composite of PTFE/perluorosulphonic acid and 7.5 F/g and 1.0 F/g for PVA-KOH and sulphonated PEEK electrolyte, respectively. Modules of 5F (2.0V) were developed using carbon electrodes and composites of PTFE/perflurosulphonic as electrolyte. The maximum energy stored in these modules, was of the order of 7.5 Watth/kg. ©The Electrochemical Society.


Puthusseri D.,Indian Institute of Technology Madras | Baby T.T.,Indian Institute of Technology Madras | Bhagavathi Parambhath V.,Indian Institute of Technology Madras | Natarajan R.,Center for Fuel Cell Technology of India | Sundara R.,Indian Institute of Technology Madras
International Journal of Hydrogen Energy | Year: 2013

A novel carbon nanostructure grown by catalytic chemical vapour deposition technique has been applied as an electrocatalyst support for oxygen reduction reaction in proton exchange membrane fuel cell. The growth of carbon nanostructure (CNS) is carried over a low cost bi-metal oxide catalyst (Fe-Sn-O) synthesized by sol-gel technique. Platinum nanoparticle decoration on Fe-Sn-O incorporated CNS (CNS-FSO) is performed by ethylene glycol reduction method. The structural as well as morphological analysis confirms the formation of CNS-FSO and platinum decoration on CNS-FSO. The electrochemically active surface area (ECSA) of platinum decorated CNS-FSO (Pt/CNS-FSO) is 68 m2 g -1, as revealed from cyclic voltammetry. Polarization studies are carried out at different temperatures (40 °C, 50 °C and 60 °C) to exploit the oxygen reduction reaction activity of Pt/CNS-FSO. A maximum power density of 449 mW cm-2 (without back pressure) at 60 °C shows the potential of this novel CNS-FSO as an electrocatalyst support in proton exchange membrane fuel cell. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Seetharaman S.,Center for Fuel Cell Technology of India | Ramya K.,Center for Fuel Cell Technology of India | Dhathathreyan K.S.,Center for Fuel Cell Technology of India
AIP Conference Proceedings | Year: 2013

A simple and effective method for the preparation of sulfonated polyether ether ketone (SPEEK) based composites with electrochemical reduced graphene oxide (EGO) as inorganic fillers has been described. The resulting dispersions are homogeneous and the cast membranes show significant improvement on tensile strength and thermal properties. It has high ionic conductivity and is cost effective making it a promising alternative membrane for electrochemical applications. © 2013 AIP Publishing LLC.


Ramya C.S.,Center for Fuel Cell Technology of India | Subramaniam C.K.,Center for Fuel Cell Technology of India | Dhathathreyan K.S.,Center for Fuel Cell Technology of India
Journal of the Electrochemical Society | Year: 2010

A solid-state electrochemical double-layer capacitor (EDLC) was assembled with perfluorosulfonic acid based electrolyte in the HK+, Na +, and K+ forms and with carbon as electrodes (surface area: 260 m2 /g). The performance of these EDLCs was studied using cyclic voltammetry, impedance spectroscopy, and charge-discharge profiles. The assembled cells behaved as EDLCs with a maximum operating voltage of 2.0 V. The specific capacitance was 20 F/g for the electrolyte in HK+ form, 40 F/g for the Na+ form, and 55 F/g for the K+ form. The increase in the specific capacitance may be attributed to the increase in the charge carrying capacity as we move from the proton form (HK+) to the K+ form. There is an increase in the charge density from 1.0 C/ cm2 for the electrolyte in the HK+ form to 6.0 C/ cm 2 for the electrolyte in the K+ form. © 2010 The Electrochemical Society.

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