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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Electrochemical behavior of β-MnO{sub 2} and MnOOH nanorods in different electrolytes

A manganese dioxide (β-MnO{sub 2}) and MnOOH nanoparticles has been synthesized by hydrothermal method. As prepared samples are analyzed by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). FESEM showed rod morphology within the diameter of 50–200 and length of few nanometers. These nanorods are immobilized on a Glassy Carbon Electrode (GCE) by drop cast method. The comparative electrochemical behavior of β-MnO{sub 2} and MnOOH rod modified GCE electrodes are analyzed by cyclic Voltammetry (CV) method in different electrolytes of 0.1M KCl, 0.1M Na{sub 2}SO{sub 4}, 0.1M NaOH, 0.1M PBS, 0.1M H{sub 2}SO{sub 4}. From the cyclic Voltammetry analysis found that in all the electrolytes both β-MnO{sub 2} and MnOOH modified GCE electrodes exhibit electrochemical behavior and KCl shows well redox properties as compared with others. There is also an observable difference in reduction potential value of both crystalline nanostructurers and concluded that β-MnO{sub 2} has high catalytic ability as compared with MnOOH rods.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Study on synthesis and electrochemical properties of hematite nanotubes for energy storage in supercapacitor

Hematite nanotubes (α-Fe{sub 2}O{sub 3} NTs) are synthesized via a cost-effective and environmental-friendly hydrothermal technique. Field emission scanning electron microscopy and X-ray powder diffraction analyses reveal the formation of α-Fe{sub 2}O{sub 3} NTs with high crystallinity and purity. Optical behavior of α-Fe{sub 2}O{sub 3} NTs is studied employing UV-visible spectroscopy. Electrochemical properties of the as-prepared electrode material are investigated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in a three electrode cell. The synthesized α-Fe{sub 2}O{sub 3} NTs present enhanced pseudocapacitive performance with high specific capacity of 230 Fg{sup −1} at current density of 1 Ag{sup −1}. The prepared α-Fe{sub 2}O{sub 3} NTs can be utilized as a potential electrode material for electrochemical capacitor applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Electrodeposited nanostructured MnO{sub 2} for non-enzymatic hydrogen peroxide sensing

Electrodeposited MnO{sub 2} nanostructure was synthesized on indium tin oxide coated glass electrode by cyclic voltammetry. The as obtained samples were subsequently characterized by atomic force microscopy and their electro-catalytic response towards hydrogen peroxide in alkaline medium of 0.1M NaOH was studied using cyclic voltammetry and amperometry.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

3D dendritic α-Fe{sub 2}O{sub 3} nano-architectures: Synthesis and its application on electrochemical non-enzymatic H{sub 2}O{sub 2} sensing

In this manuscript we have successfully synthesized a large scale 3D dendritic α-Fe{sub 2}O{sub 3} hierarchical structure via a hydrothermal reaction. The crystallinity, composition, purity, morphology of the synthesized α-Fe{sub 2}O{sub 3} are characterized by powder X-ray diffraction (PXRD), field emission scanning electron microscopic (FESEM), energy dispersive X-ray spectroscopic (EDS). FESEM image reveals that the individual α-Fe{sub 2}O{sub 3} dendrite consists of a long central trunk with secondary and tertiary branches. For electrochemical H{sub 2}O{sub 2} sensing we have carried out cyclic voltammetry (CV), amperometric i-t measurement. It has been found that the current density vs. H{sub 2}O{sub 2} concentration calibration curve is linear in nature. The present study reveals that the dendritic α-Fe{sub 2}O{sub 3} hierarchical structure exhibits very sensitive electrochemical sensing capability towards H{sub 2}O{sub 2} reduction.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Microwave synthesis and electrochemical characterization of Mn/Ni mixed oxide for supercapacitor application

Nanostructured Mn/Ni mixed metal oxide was synthesized at ambient temperature by facile microwave irradiation technique. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. X-ray diffraction analysis confirmed the formation of Mn/Ni mixed oxide in rhombohedral phase and the grain size calculated was found to be 87 nm. The irregular spherical morphology of the prepared sample was exhibited by the SEM images. The characteristic peaks of FTIR at about 630 cm{sup −1} and 749 cm{sup −1} were attributed to the Mn-O and Ni-O stretching vibrations respectively. The presence of both Mn and Ni in the prepared sample was validated by the EDS spectra which in turn confirmed the formation of mixed oxide. Cyclic voltammetry and galvanostatic chargedischarge measurements were employed to investigate the electrochemical performance of the mixed oxide. The cyclic voltammetry curves demonstrated good capacitive performance of the sample in the potential window −0.2V to 0.9V. The charge discharge study revealed the suitability of the prepared mixed oxide for the fabrication of supercapacitor electrode.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Nanofiber of Mn{sub 3}O{sub 4}: Fabrication and application as supercapacitor electrode

Mn{sub 3}O{sub 4}–nanofiber with high aspect ratio is prepared by a simple electrospinning process. The thermal, structural and morphological characterizations are carried out by TGA, XRD and FESEM, respectively. To assess the property of nanofiber for the use in supercapacitors, cyclic voltammetry (CV) and galvanostatic charging-discharging (GCD) are performed in 2M KOH electrolyte with the potential window ranging from +0.42V to −0.45V. Effect of polymer concentration and electric field intensity on the diameter of as-spun nanofiber was studied. Further, appropriate heating rate was used for sintering to obtain aligned nanofiber. High specific capacitance of 150(±5) F g{sup −1} is obtained by Mn{sub 3}O{sub 4} nanofibers. The rate performance is also found to be good. This improved performance in terms of high specific capacitance and rate capability is ascribed to the nanofabric morphology which provides more active sites and easy access path for ions/electrons.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Performance of electrical double layer capacitors fabricated with gel polymer electrolytes containing Li{sup +} and K{sup +}-salts: A comparison

The comparative performance of the solid-state electrical double layer capacitors (EDLCs) based on the multiwalled carbon nanotube (MWCNT) electrodes and poly (vinaylidinefluoride-co-hexafluoropropyline) (PVdF-HFP) based gel polymer electrolytes (GPEs) containing potassium and lithium salts have been studied. The room temperature ionic conductivity of the GPEs have been found to be ∼3.8×10{sup −3} and 5.9×10{sup −3} S cm{sup −1} for lithium and potassium based systems. The performance of EDLC cells studied by impedance spectroscopy, cyclic voltammetry and constant current charge-discharge techniques, indicate that the EDLC with potassium salt containing GPE shows excellent performance almost equivalent to the EDLC with Li-salt-based GPE.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Rapid synthesis of monodispersed highly porous spinel nickel cobaltite (NiCo{sub 2}O{sub 4}) electrode material for supercapacitors

Monodispersed highly porous spinel nickel cobaltite electrode material was successfully synthesized in a short time using combustion technique. Single phase cubic nature of the spinel nickel cobaltite with average crystallite size of 24 nm was determined from X-ray diffraction study. Functional groups present in the compound were determined from FTIR study and it further confirms the spinel formation. FESEM images reveal the porous nature of the prepared material and uniform size distribution of the particles. Electrochemical evaluation was performed using Cyclic Voltammetry (CV) technique, Chronopotentiometry (CP) and Electrochemical Impedance Spectroscopy (EIS). Results reveal the typical pseudocapacitive behaviour of the material. Maximum capacitance of 754 F/g was calculated at the scan rate of 5 mV/s, high capacitance was due to the unique porous morphology of the electrode. Nyquist plot depicts the low resistance and good electrical conductivity of nickel cobaltite. It has been found that nickel cobaltite prepared by this typical method will be a potential electrode material for supercapcitor application.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Pseudo capacitive performance of copper oxide thin films grown by RF sputtering

Thin films of Copper Oxide were prepared by radio frequency magnetron sputtering on steel substrates maintained at 250°C under different RF powers ranging from 150W to 250W by keeping the sputtering pressure at 5.7×10{sup −3} mbar and O{sub 2}:Ar ratio of 1:7. The influence of RF power on the pseudo capacitive performance of thin films was studied. The X-ray diffraction studies and Raman studies indicates that all the thin films exhibits CuO phase. The electrochemical studies was done by using three electrode configuration with platinum as reference electrode. From the cyclic voltammetry studies a high rate pseudocapacitance of 227 mFcm{sup −2} at 0.5 mVs{sup −1} and 77% of capacity retention after 1000 cycles was obtained for the CuO thin films prepared at an RF power of 220W.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Novel synthesis of Ni-ferrite (NiFe{sub 2}O{sub 4}) electrode material for supercapacitor applications

Novel nanocrystalline NiFe{sub 2}O{sub 4} has been synthesized through combustion route using citric acid as a fuel. Phase of the synthesized material was analyzed using powder X-ray diffraction. The XRD study revealed the formation of spinel phase cubic NiFe{sub 2}O{sub 4} with high crystallinity. The average crystallite size of NiFe{sub 2}O{sub 4} nanomaterial was calculated from scherrer equation. The electrochemical properties were realized by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The electrode material shows a maximum specific capacitance of 454 F/g with pseudocapacitive behavior. High capacitance retention of electrode material over 1000 continuous charging-discharging cycles suggests its excellent electrochemical stability. The results revealed that the nickel ferrite electrode is a potential candidate for energy storage applications in supercapacitor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

A new bimetallic plasmonic photocatalyst consisting of gold(core)-copper(shell) nanoparticle and titanium(IV) oxide support

Ultrathin Cu layers (∼2 atomic layers) have been selectively formed on the Au surfaces of Au nanoparticle-loaded rutile TiO{sub 2} (Au@Cu/TiO{sub 2}) by a deposition precipitation-photodeposition technique. Cyclic voltammetry and photochronopotentiometry measurements indicate that the reaction proceeds via the underpotential deposition. The ultrathin Cu shell drastically increases the activity of Au/TiO{sub 2} for the selective oxidation of amines to the corresponding aldehydes under visible-light irradiation (λ > 430 nm). Photochronoamperometry measurements strongly suggest that the striking Cu shell effect stems from the enhancement of the charge separation in the localized surface plasmon resonance-excited Au/TiO{sub 2}.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Structural, electrical and electrochemical properties of Li{sub 4}Zr{sub x}Si{sub 1-x}O{sub 4} (0.02 ≤ x ≤ 0.06) ceramic electrolytes

The aim of this work was to investigate the structural, electrical and electrochemical properties of Li{sub 4}Zr{sub x}Si{sub 1-x}O{sub 4} (0.02 ≤ x ≤ 0.06) compounds prepared via sol gel method. The X-ray Diffraction results showed that all compounds can be indexed to monoclinic structure in space group P2{sub 1/m}. The Li{sub 4}Zr{sub 0.06}Si{sub 0.94}O{sub 4} compound showed highest bulk, grain boundary and total conductivity values of 1.19 × 10{sup −4} S cm{sup −1}, 4.75 × 10{sup −5} S cm{sup −1} and 3.41 × 10{sup −5} S cm{sup −1} respectively. The insertion of Zr{sup 4+} is found to enhance conductivity of the parent sample Li{sub 4}SiO{sub 4}. Linear sweep voltammetry results showed that Li{sub 4}Zr{sub 0.06}Si{sub 0.94}O{sub 4} ceramic electrolytes was electrochemically stable up to 5.07 V versus a Li{sup +}/Li{sup +} reference electrode.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Analytical solutions of the planar cyclic voltammetry process for two soluble species with equal diffusivities and fast electron transfer using the method of eigenfunction expansions

Cyclic voltammetry is a powerful tool that is used for characterizing electrochemical processes. Models of cyclic voltammetry take into account the mass transport of species and the kinetics at the electrode surface. Analytical solutions of these models are not well-known due to the complexity of the boundary conditions. In this study we present closed form analytical solutions of the planar voltammetry model for two soluble species with fast electron transfer and equal diffusivities using the eigenfunction expansion method. Our solution methodology does not incorporate Laplace transforms and yields good agreement with the numerical solution. This solution method can be extended to cases that are more general and may be useful for benchmarking purposes.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Structure and spectroscopic properties of ruthenium(II) bipyridyl N-benzoyl-N'-(1,10-phenanthrolin-5-Yl)-thiourea

Ruthenium bipyridyl incorporating phenanthroline with thiourea molecules, [Ru(bpy){sub 2}(Phen-BT)](PF{sub 6}){sub 2}], has been synthesized and characterized by spectroscopic and electrochemical techniques. The infrared spectra of the complex shows the characteristics stretching frequencies for N-H at 3646 and 3585 cm{sup −1}, ν(C-N){sub phen} 1426 cm{sup −1}, ν(C=O) 1675 cm{sup −1}, ν(C=S) 1246 cm{sup −1}, ν(C-H){sub aromatic} 3353-3086 cm{sup −1}, ν(C-N){sub aliphatic} 1169-1026 cm{sup −1}, ν(C-H){sub bend} 764 cm{sup −1} and ν(PF{sub 6}{sup −}){sub free} 842 cm{sup −1}. The complex reveals two π→π* absorption bands at 237 (ε=26,302) and 286 nm (ε=36,848), which were assigned to the phenanthroline and bipyridyl moieties, respectively. A slightly broad and low energy band in the UV-vis spectrum at 450 nm (ε=7,209) of the complex was assigned to a MLCT transition. Besides, the complex also exhibits an emission band at 615 nm that arises from an excitation with a 440 nm light energy. The cyclic voltammetry of the complex shows an oxidation potential at +1.305 V vs. SCE that corresponds to the formal oxidation of Ru(II) to Ru(III)

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Electrochemical characterization of aminated acrylic conducting polymer

New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25μm particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

A preliminary study on the potency of nanofluids as the electro-active materials for nanoelectrofuel flow batteries

This study presents a characterization of nanofluids as electroactive materials with dispersing metal oxide nanoparticles into aqueous polyelectrolytes of 20 wt.%, in particular, their electrochemical activites. The fundamental characterizations including X-ray diffraction, transmission electron microscopy, and Fourier ttransform iinfrared measurement were performed to ensure metal oxide component used in this work. Alumina (Al{sub 2}O{sub 3}) and copper oxide (CuO) nanoparticles of 0.5 vol.% in volume fraction were dispersed into Poly(diallyldimethylammonium chloride) solution (PDADMAC) and Poly(sodium 4-styrenesulfonate) (PSS), respectively. Alumina and copper oxide nanoparticles were dispersed into ionic solution with volume fraction of 0.5 vol.% by using two-step method. The general cyclic voltammetry measurement was used to analyze electrochemical behavior within three-electrode cell setup. The results show that PSS-based nanofluids demonstrate redox process. However, unclearly redox phenomenon was depicted PDADMAC-based nanofluids. Dispersing nanoparticles could shift pure ionic solution’s cyclic profile. It is clear that a significant impact on electrochemical behavior can be provided because of the existence metal oxide nanoparticles into polyelectrolyte solution.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Carbon electrode for desalination purpose in capacitive deionization

Carbon electrodes for desalination purpose have been successfully synthesized using activated carbon powder (BET surface area=700 – 1400 m{sup 2}/g), carbon black and polyvinyl alcohol (PVA) binder by cross-linking method with glutaric acid (GA) at 120 °C. The electrochemical properties of the carbon electrodes were analyzed using electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) whilst the physical properties were observed with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX). In order to assess the desalting performance, salt removal experiments were performed by constructing a capacitive deionization unit cell with five pairs of carbon electrodes. For each pair consisted of two parallel carbon electrodes separated by a spacer. Desalination and regeneration processes were also observed in the salt-removal experiments. The salt-removal experiments were carried out in single-pass mode using a solution with 0.1 M NaCl at a flow rate of 10 mL/min. A voltage of 3 V was applied to the cell for 60 minutes for both processes in desalination and regeneration. The result showed that the percentage value of the salt-removal was achieved at 20%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Preparation and characterization of WO{sub 3} nanoparticles, WO{sub 3}/TiO{sub 2} core/shell nanocomposites and PEDOT:PSS/WO{sub 3} composite thin films for photocatalytic and electrochromic applications

In this study, monoclinic WO{sub 3} nanoparticles were obtained by thermal decomposition of (NH{sub 4}){sub x}WO{sub 3} in air at 600 °C. On them by atomic layer deposition (ALD) TiO{sub 2} films were deposited, and thus core/shell WO{sub 3}/TiO{sub 2} nanocomposites were prepared. We prepared composites of WO{sub 3} nanoparticles with conductive polymer as PEDOT:PSS, and deposited thin films of them on glass and ITO substrates by spin coating. The formation, morphology, composition and structure of the as-prepared pure and composite nanoparticles, as well thin films, were studied by TEM, SEM-EDX and XRD. The photocatalytic activity of both the WO{sub 3} and core/shell WO{sub 3}/TiO{sub 2} nanoparticles was studied by decomposing methyl orange in aqueous solution under UV light irradiation. Cyclic voltammetry measurements were performed on the composite PEDOT:PSS/WO{sub 3} thin films, and the coloring and bleaching states were studied.

77 NANOSCIENCE AND NANOTECHNOLOGY↗