Addressing the Stability of Bulk Electrode Materials in the Electrochemical Methanol Oxidation

2019 ◽  
Vol 166 (14) ◽  
pp. F1079-F1087
Author(s):  
Ridha Zerdoumi ◽  
Leonard Rößner ◽  
Marc Armbrüster
Keyword(s):  
Methanol Oxidation ◽  
Electrode Materials ◽  
The Stability ◽  
Bulk Electrode

scholarly journals Chemical Preparation Routes and Lowering the Sintering Temperature of Ceramics

Ceramics ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 312-339
Author(s):  
Philippe Colomban
Keyword(s):  
Electrode Materials ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Sol Gel ◽  
Transient Liquid Phase ◽  
Ceramic Matrix Composites ◽  
Thermomechanical Properties ◽  
Matrix Composites ◽  
Chemical Preparation ◽  
The Stability

Chemically and thermally stable ceramics are required for many applications. Many characteristics (electrochemical stability, high thermomechanical properties, etc.) directly or indirectly imply the use of refractory materials. Many devices require the association of different materials with variable melting/decomposition temperatures, which requires their co-firing at a common temperature, far from being the most efficient for materials prepared by conventional routes (materials having the stability lowest temperature determines the maximal firing temperature). We review here the different strategies that can be implemented to lower the sintering temperature by means of chemical preparation routes of oxides, (oxy)carbides, and (oxy)nitrides: wet chemical and sol–gel process, metal-organic precursors, control of heterogeneity and composition, transient liquid phase at the grain boundaries, microwave sintering, etc. Examples are chosen from fibers and ceramic matrix composites (CMCs), (opto-)ferroelectric, electrolytes and electrode materials for energy storage and production devices (beta alumina, ferrites, zirconia, ceria, zirconates, phosphates, and Na superionic conductor (NASICON)) which have specific requirements due to multivalent composition and non-stoichiometry.

Modified Carbon Papers as Electrode Materials of all-Vanadium Redox Flow Battery

2013 ◽  
Vol 1492 ◽  
pp. 15-23
Author(s):  
Chih-Hsing Leu ◽  
Shu-Yuan Chuang ◽  
Kan-Lin Hsueh ◽  
Jia-Ming Huang ◽  
Chia-Chun Chung ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Binding Energy ◽  
Redox Reaction ◽  
Acid Treatment ◽  
Electrode Materials ◽  
Carbon Materials ◽  
Vanadium Redox Flow Battery ◽  
Hydrolysis Reaction ◽  
Ozone Treatment ◽  
The Stability

ABSTRACTThe electrode materials for VRFB should possess higher electric conductivity, corrosion resistance and hydrophilic properties in sulfuric acid. The characteristics of the electrode materials affect the stability and the energy efficiency of VRFB. Carbon materials are the best suited for VRFB applications. In this study, the calcined treatment, acid treatment and ozone treatment were used to modify the surface of carbon papers. The redox reaction of [VO]2+/[VO2]+ on the modified carbon papers was evaluated by cyclic voltammetry (CV). The surface compositions of carbon materials were analyzed by X-ray photoelectron spectrometry (XPS). The experimental results reveal that three oxidative methods enhance the redox reaction of [VO]2+/[VO2]+. The calcined treatments and acid treatments also enhanced hydrolysis reaction. The mole ratio of O/C apparently increased, but the binding energy of C1s and O1s were not chemically shifted in the acid treatment. The intensity of binding energy of O1s, between 532 eV and 534 eV, apparently increased in the ozone and calcined treatments. The Ox treated samples were more hydrophilic than the Oz treated samples. In the Ox treated samples, the decrease of Rct value indicates that was contributed from the redox reaction of [VO]2+/[VO2]+ and hydrolysis reaction. It does not completely benefit the energy efficiency of VRFB. The 5 x 5 cm2 modified carbon papers were used as electrode materials in the VRFB. The voltage efficiency, coulomb efficiency and energy efficiency reached 93 %, 90 % and 83 %, respectively, at a current density of 12 mA．cm-2 at 0.8-1.8 V.

Electrodes and Barriers for Dram and Feram: Processing, Integration, and Fundamentals

2000 ◽  
Vol 655 ◽  
Author(s):  
K.L. Saenger ◽  
P.C. Andricacos ◽  
S.D. Athavale ◽  
J.D. Baniecki ◽  
C. Cabral ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Random Access ◽  
Random Access Memory ◽  
X Ray Diffraction ◽  
Oxide Electrode ◽  
Access Memory ◽  
X Ray ◽  
Barrier Materials ◽  
The Stability ◽  
Density Dynamic

AbstractMaterials requirements for electrodes and barriers in high density dynamic random access memory (DRAM) and ferroelectric random access memory (FERAM) are reviewed, and some approaches to barrier materials and device geometries are described. Electrode/barrier topics covered in more detail include Pt reactivity with Si-containing barriers and dielectric overlayers, the application of a Bragg-Brentano x-ray diffraction technique to quantitatively probe Pt and Ir electrode morphology and thickness changes during ferroelectric processing, the stability of metal oxide electrode materials in reducing ambients, electrode patterning techniques (including Pt electroplating), and electrical properties of 3-D capacitors in 256k arrays as a function of top electrode annealing treatments.

18O study of the oxidation of reactively sputtered Ti1−xAlxN barrier

2001 ◽  
Vol 16 (9) ◽  
pp. 2591-2599 ◽  
Author(s):  
M. C. Hugon ◽  
F. Varniere ◽  
F. Letendu ◽  
B. Agius ◽  
I. Vickridge ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Nuclear Reaction Analysis ◽  
Oxidation Reactions ◽  
Electrically Conductive ◽  
Al Content ◽  
Perovskite Materials ◽  
Sample Composition ◽  
Before And After ◽  
The Stability ◽  
Concentration Depth Profiles

The preparation of high-permittivity perovskite materials requires high-temperature (550–750 °C) oxidizing environments, providing stringent limitations on the choice of electrode materials. To minimize interdiffusion and oxidation reactions, an electrically conductive diffusion barrier such as Ti1−xAlxN is needed below the electrode material (Pt, IrO2, RuO2…). Ti1−xAlxN films were deposited by multitarget reactive sputtering in a mixture of Ar and N2. The stability of these films has been investigated under typical conditions for crystallization of perovskite dielectrics. Sample composition was characterized using Rutherford backscattering spectroscopy and nuclear reaction analysis. In particular, the concentration depth profiles of both 18O and 27Al were measured before and after RTA treatments via the narrow resonances of 18O(p,α)15N at 151 keV (FWHM = 100 eV) and 27Al(p,γ)28Si at 992 keV (FWHM = 100 eV). The different 18O excitation curves show that the oxidation resistance increases with Al incorporation. The Al excitation curves indicate a uniform Al content for as-deposited TixAl1−xN and reveal Al diffusion to the surface during the oxidation process which indicates the formation of an Al-rich oxide layer at the TixAl1−xN surface, leaving a layer depleted in Al below it.

scholarly journals Physicochemical and Electrical Properties of Praseodymium Oxides

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Sergio Ferro
Keyword(s):  
Catalytic Activity ◽  
Electrical Properties ◽  
Hydrogen Evolution ◽  
Noble Metal ◽  
Hydrogen Evolution Reaction ◽  
Electrode Materials ◽  
Praseodymium Oxide ◽  
Lanthanide Oxides ◽  
New Ideas ◽  
The Stability

The industrial research is continuously looking for novelties that could improve the applied processes, increasing the yields, lowering the costs, or improving the performances. In industrial electrochemistry, one more aspect is the stability of electrode materials, which is generally balanced by the catalytic activity: the higher the latter, the lower the former. A compromise has to be found, and an optimization is often the result of new ideas that completely change the way of thinking. Praseodymium-oxide-based cathodes have been proved to be quite interesting devices: the hydrogen evolution reaction is guaranteed by the presence of a noble metal (platinum and/or rhodium), while the stability and poisoning resistance seem to be strongly improved by the presence of lanthanide oxides.

On the Stability and Reactivity of Redox Shuttles in Their Neutral and Radical Cation Forms

2015 ◽  
Vol 1740 ◽  
Author(s):  
Susan A. Odom ◽  
Matthew Casselman ◽  
Aman Preet Kaur ◽  
Selin Ergun ◽  
Naijao Zhang
Keyword(s):  
Lithium Ion Batteries ◽  
Radical Cation ◽  
Electrode Materials ◽  
Lithium Ion ◽  
Radical Cations ◽  
Top Performers ◽  
Redox Shuttles ◽  
Redox Shuttle ◽  
The Stability ◽  
Overcharge Protection

ABSTRACTThe performance of aromatic compounds as redox shuttles for overcharge protection in lithium-ion batteries is quite variable and is often difficult to predict. Redox shuttles may decompose in battery electrolyte in their neutral and radical cation forms, both of which are present during overcharge protection. While hundreds of compounds have been evaluated as redox shuttle candidates and a few have stood out as top performers, the reasons for increased stability over similar candidates with slightly different structures is often unclear, and the exploration of decomposition of redox shuttles has been severely limited, restricting our ability to design improved versions of redox shuttles that do not suffer from the same reactions in lithium-ion batteries. To better understand the stability and reactivity of redox shuttles (also relevant to the improvement of positive electrode materials in non-aqueous redox flow batteries) our research has focused on measuring the stability of neutral and oxidized forms of redox shuttle candidates as well as using a variety of spectroscopic methods to analyze the byproducts of decomposition, both from radical cations generated in model solvents and electrolytes from postmortem analysis of failed batteries.

scholarly journals Investigating the Cycling Stability of Fe2WO6 Pseudocapacitive Electrode Materials

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1405
Author(s):  
Julio César Espinosa-Angeles ◽  
Nicolas Goubard-Bretesché ◽  
Eric Quarez ◽  
Christophe Payen ◽  
Moulay-Tahar Sougrati ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Negative Electrode ◽  
Cycling Stability ◽  
Transmission Electron ◽  
Surface And Bulk Characterization ◽  
The Stability ◽  
A Minor ◽  
First Time ◽  
Good Cycling Stability ◽  
Negative Electrode Material

The stability upon cycling of Fe2WO6 used as a negative electrode material for electrochemical capacitors was investigated. The material was synthesized using low temperature conditions for the first time (220 °C). The electrochemical study of Fe2WO6 in a 5 M LiNO3 aqueous electrolyte led to a specific and volumetric capacitance of 38 F g−1 and 240 F cm−3 when cycled at 2 mV·s−1, respectively, associated with a minor capacitance loss after 10,000 cycles. In order to investigate this very good cycling stability, both surface and bulk characterization techniques (such as Transmission Electron Microscopy, Mössbauer spectroscopy, and magnetization measurements) were used. Only a slight disordering of the Fe3+ cations was observed in the structure, explaining the good stability of the Fe2WO6 upon cycling. This study adds another pseudocapacitive material to the short list of compounds that exhibit such a behavior up to now.

scholarly journals Synthesis, crystal structure and physical properties of the TbCo4.5SixLi0.5-x solid solution

2021 ◽  
Vol 22 (3) ◽  
pp. 577-584
Author(s):  
I. Stetskiv ◽  
V. Kordan ◽  
I. Tarasiuk ◽  
V. Pavlyuk
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
Electrode Materials ◽  
Rietveld Method ◽  
Structure Type ◽  
Experimental Conditions ◽  
X Ray ◽  
Cell Parameters ◽  
Arc Melting ◽  
The Stability

Alloys from the region of existence of the solid solution TbCo4.5SixLi0.5-x were synthesized by arc melting. Quantitative and qualitative composition of alloys and powders of electrode materials was determined by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The Tb/Co/Si ratio in the samples was confirmed by X-ray fluorescence spectroscopy. The change in cell parameters within the solid solution existence was established by the results of X-ray powder diffraction (TbCo4.5SixLi0.5-x, x = 0.1–0.4: a = 4.9518(5) – 4.9324(3), c = 3.9727(4) – 3.9746(3) Å). The crystal structure of the solid solution was determined by the Rietveld method (CaCu5 structure type, space group P6/mmm). Cobalt atoms are partially replaced by silicon and lithium only in 2c position. The ability of alloys to reversibly absorb hydrogen was studied by the method of electrochemical hydrogenation. Under experimental conditions the amount of deintercalated hydrogen was about 0.19 H/f.u. The change in cell parameters after hydrogenation (volume increases from 83.74(1) to 85.54(6) Å3) and the stability of the electrode in the electrolyte solution was further confirmed by X-ray phase analysis. Measurements of the electrical resistivity of the samples indicated a decrease of resistivity value with a slight increase in the amount of alkali metal in samples.

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