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Development of free standing anodes of high aspect ratio carbon materials for rechargeable Li-ion batteries
No full textCarbon materials of various types have been extensively used as negative electrode materials for rechargeable
Li-ion batteries because of their consistent performance and potentialities. High aspect ratio (>1000)
carbons such as carbon fibers and multiwalled carbon nanotubes (MWCNTs) of different dimensions have
been employed to fabricate free standing anode materials. Various characterization techniques such as
SEM, TEM, TGA, XRD, Raman spectroscopy, mercury intrusion porosimetry has been carried out to evaluate
the structure of the anode that was further correlated to its performance in Li-ion cell. MWCNTs
prepared under specified conditions not only exhibits high purity and crystallinity in structure but also
shows exceptional electrochemical behavior of increasing capacity with successive cycling. This is probably
due to the formation of a very constructive SEI with negligible charge transfer resistance as shown
by the Nyquist plots
Trialkylsulfonium and tetraalkylammonium cations-based ionicliquid electrolytes for quasi-solid-state dye-sensitized solar cells
No full textSeven ionic liquids (ILs) based on asymmetric trialkyl sulfonium and tetraalkylammonium cations withbis(trifluoromethanesulfonyl)imide anion were prepared and characterized. Physico-chemical and elec-trochemical properties of these ionic liquids including density, decomposition temperature, viscosity andconductivity were determined. The photovoltaic parameters of dye-sensitized solar cells (DSSCs) con-taining these sulfonium and ammonium ion-based ILs were compared. Among these two groups of ILs,the DSSCs with sulfonium cation-based ILs show higher cell efficiencies than that of ammonium coun-terpart due to lower charge transfer resistance exhibited by the former when compared to the latter,as confirmed by electrochemical impedance spectroscopy (EIS). The best cell efficiency achieved in thiswork was 4.61%. Moreover, long-term durability of the quasi-solid-state DSSCs at 50◦C was investigated
Catalytic activity of Pt anchored onto graphite nanofiber-poly(3,4-ethylenedioxythiophene) composite toward oxygen reductionreaction in polymer electrolyte fuel cells
No full textThe potential of graphite nanofiber (GNF)–Poly(3,4-ethylenedioxythiophene) (PEDOT) composite isexplored as a catalyst support for polymer electrolyte fuel cells (PEFCs). Due to electron accepting natureof GNF and electron donating nature of PEDOT, the monomer EDOT adsorbs on the surface of GNF dueto strong electrostatic �–� interaction. Pt nanoparticles are impregnated on GNF–PEDOT composite byethylene glycol reduction method and their effects on electro catalytic activity for oxygen reductionreaction (ORR) are systemically studied. Pt particles supported on GNF–PEDOT with catalyst loading of0.2 mg cm−2exhibit a peak power density of 537 mW cm−2at a load current density of 1120 mA cm−2,while it was only 338 mW cm−2at a load current density of 720 mA cm−2in case of Pt particles supportedon pristine GNF. The superior behavior of GNF–PEDOT supported Pt catalyst could be exclusively cred-ited to the high graphitic nature of GNF and their mild functionalization with PEDOT increasing uniformdispersion of Pt. Indeed, the non-destructive functionalization of GNF with conducting polymer, such asPEDOT, makes them promising catalyst-supports for PEFCs
Lead-acid battery with high specific energy
No full textAn electrochemical method of manufacturing a corrosion resistant grid structure used in a lead-acid battery, said method comprising coating of substrate material such as herein described, with a metal layer of copper or nickel and a subsequent layer of lead/lead alloy followed by the electrodeposition of an organic material such as polyaniline and similar other organic material, over the above said lead/lead alloy layer by using an electrolyte such as oxalic acid to obtain a corrosion resistant grid structure used in a lead-acid battery
Alternate Zinc - Nickel alloy coating for hazardous Cadmium
No full textResearch on zinc – nickel alloy deposit from alkaline zincate cyanide free electrolyte was dealt to eliminate the use of potentially hazardous cadmium. To compare with cadmium separate deposition of cadmium from cadmium sulphate electrolyte was processed. Hull cell tests performed to determine the current density ranges with and without addition agents. SEM & EDAX, AFM, XRD observations indicated the deposit’s surface morphology and percentage of zinc & nickel present in the alloy, surface topography and crystallographic orientation. Surface characterisation studies were evaluated for cadmium also. Weight loss methods, Potentiodynamic polarization, and electrochemical impedance spectroscopy correlations show zinc – nickel alloy coatings have a better corrosion resistance and are considered to be eco friendly replacement for cadmium coatings in corrosion resistant application
Zn-Ni Alloy Deposit for Cadmium Replacement Applications
No full textZinc - nickel alloy was deposited from alkaline bath at a PH of 13-14 with the nickel percentage of 5-9%
in our prior research. Present study dealt with the research on 10-12% of Nickel at a PH of 12-13 from Zinc –
nickel alloy electrolyte and the remaining percentage of Zinc, required for corrosion resistant applications to be used for reliable alternative of cadmium. Hull cell studies was carried out to optimize current density, temperature,
agitation etc., for getting a deposition of 10-12% of Ni & 88-90 % of Zn. SEM, EDAX, XRD measurements
characterize the deposit properties and structure. Corrosion resistance measurements such as polarisation, corrosion
impedance spectra of zinc-nickel alloy were evaluated
Modified Sulfonated Poly(ether ether ketone) Based MixedMatrixMembranes for DirectMethanol Fuel Cells
No full textMixed matrix membranes based on zeolite 4A-methane sulfonic
acid (MSA)-sulfonated poly(ether ether ketone)
(SPEEK) are evaluated as a potential polymer electrolyte
membrane (PEM) for direct methanol fuel cells (DMFCs).
Ion-exchange capacity, sorption of water, and water–methanol
mixture, proton conductivity, and methanol permeability
for the mixed-matrix membranes have been extensively
investigated. The mixed-matrix membranes are also characterized
for their cross-sectional morphology, mechanical,
and thermal properties. DMFCs employing SPEEK-MSA
(20 wt.%) blend, zeolite 4A (4 wt.%)-SPEEK-MSA (20 wt.%)
mixed matrix membranes deliver peak power densities of
130 and 159 mW cm–2, respectively; while a peak power
density of only 95 mW cm–2 is obtained for the DMFC
employing pristine SPEEK membrane at 70 °C. The results
showed that these SPEEK based mixed matrix membranes
exhibit higher DMFC performance and lower methanol permeability
in comparison to Nafion-117 membran
Nucleation of copper on mild steel in copper chloride (CuCl2�2H2O)–1-ethyl-3-methylimidazolium chloride [EMIM]Cl–ethylene glycol (EG) ionic liquid
No full textA dense and adhesive Cu layer was successfully electrodeposited on mild steel in a copper chloride
(CuCl2�2H2O)–1-ethyl-3-methylimidazolium chloride [EMIM]Cl–ethylene glycol [EG] ionic liquid. The mechanism
of copper nucleation is studied using cyclic voltammetry and chronoamperometry. It is observed that
3D-instantaneous nucleation leads to a bright nano-structured deposit. The morphology of the deposit was
characterized SEM and X-ray diffraction techniques. The deposition method was found to take place in an
environmentally friendly green electrolyte without co-ligands such as cyanide and volatile toxic solvent
A new route for the formation of Au nanowires and application of shape-selective Au nanoparticles in SERS studies
No full textA new route for the formation of shape-selective Au nanoparticles (NPs) has been demonstrated. The
reduction of Au(III) ions was done with alkaline 2,7-DHN in CTAB micellar media under 30 min of
continuous UV-irradiation. The reaction results in uniform Au nanospheres and Au nanowires. With the
change in Au(III) ion to CTAB molar ratio, the particles’ size and shape can be tuned. Au nanorods and
nanoprisms are synthesized via seed mediated growth and microwave heating methods and the
particles are characterized by several spectroscopic tools. The shape effects of the four different types of
Au NPs were investigated using surface enhanced Raman scattering (SERS) studies. The results showed
that the SERS intensity increases with the change in NPs’ shape from nanospheres to nanorods to
nanowires to nanoprisms. The highest enhancement observed for the nanoprisms is due to the
presence of a maximum number of sharp edges or surface active rough surfaces compared to the
smooth surfaces of the nanospheres. This high enhancement factor (EF) of these multiple shaped Au
NPs might find potential application in detection of single molecules or in many other fields like
detection of bio-molecules, bioassays, bio-diagnosis or even clinical diagnostics and in medical therap
Current and clamping pressure distribution studies on the scale up issues in direct methanol fuel cells
No full textThe focus of the present study is to obtain the performance on a larger area (45 cm2) equivalent to
that obtained on a smaller area (4 cm2) single cell DMFC overcoming performance losses associated
with scale-up of single cell DMFCs due to uneven clamping pressure distribution on MEA through the
end-plates and non-uniform distribution of reactants to MEA. The current distribution profile along
the cathode flow field channel is measured using a segmented current measurement plate to understand
the influence of uneven clamping pressure distribution on the MEA. Uniform current distribution
in a single cell DMFC with 45 cm2 electrode area is achieved using angular ribbed end-plates. Also,
in the present study performance of conventional DMFC is compared with that of mixed-reactant
(MR), i.e. methanol and air. Performance of DMFC operating on mixed reactant (MeOH + air) at anode
and air at cathode is superior compared with DMFC operating on aqueous methanol at anode and
air at cathode. A power density of 55 mW cm−2 at 0.3 V is obtained for a DMFC single cell with an
effective area of 45 cm2 using angular ribbed end-plates and MR at anode and air at cathode under
ambient conditions. Pressure film test is conducted to obtain the clamping pressure distribution and
cyclic voltammetry is performed to obtain the electrochemical surface area of small and large area
electrode