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Drennan, Dina M., Raji E. Koshy, David B. Gent et Charles E. Schaefer. « Electrochemical treatment for greywater reuse : effects of cell configuration on COD reduction and disinfection byproduct formation and removal ». Water Supply 19, no 3 (27 juillet 2018) : 891–98. http://dx.doi.org/10.2166/ws.2018.138.
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Abstract Electrochemical (EC) treatment presents a low-energy, water-reuse strategy with potential application to decentralized greywater treatment. This study focused on evaluating the impacts of cell configuration, current density, and cathode material on chemical oxygen demand (COD) removal and disinfection byproduct (DBP) formation in greywater. The formation and/or cathodic removal of active chlorine, perchlorate, haloacetic acids, and trihalomethanes were assessed during EC treatment. DBP formation was proportional to current density in undivided EC cells. Sequential anodic-cathodic treatment in divided EC cells resulted in COD removal in the catholyte and anolyte. The anodic COD removal rate (using a mixed metal-oxide anode) was greater than the cathodic removal rate employing boron-doped diamond (BDD) or graphite cathodes, but anodic and cathodic COD removal was similar when a stainless-steel cathode was used. The overall energy demand required for 50% COD removal was 24% less in the divided cells using the graphite or BDD cathodes (13 W-h L−1) compared to undivided cells (20 W-h L−1). Perchlorate formation was observed in undivided experiments (>50 μg/L), but not detected in divided experiments. While haloacetic acids (HAAs) and trihalomethanes (THMs) were generated anodically; they were removed on the cathode surface in the divided cell. These results suggest that divided configurations provide potential to mitigate DBPs in water reuse applications.
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Kolesnikov, A. V., et E. I. Ageenko. « Comparative studies of the discharge of hydronium ions on zinc, copper and aluminum cathodes ». Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy) 28, no 6 (7 décembre 2022) : 22–31. http://dx.doi.org/10.17073/0021-3438-2022-6-22-31.
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Electrochemical reduction of hydrogen (hydronium ion) was carried out on zinc, aluminum and copper cathodes from acidic aqueous solutions containing sulfuric acid (0.09, 0.18 and 0.36 mol/l) to study the effect of electrolyte acidity, the type of cathodes used and potential values on electrolysis indicators. The studies were carried out on the potentiostat using a three-electrode cell under conditions of intensive electrolyte stirring with a magnetic stirrer. At the initial stage, electrolysis was performed in the following modes: potentiodynamic measurements at a sweep rate of 1 mV/s in the potential range Е = –(700÷850) mV on a copper and aluminum electrode and Е = –(1000÷1150) mV on a zinc electrode. In the indicated potential range, hydronium discharge parameters at each cathode were calculated: Tafel slope, apparent transfer coefficients and exchange currents. Dependences of these parameters on electrolyte acidity were considered. Average values of steady state potentials were obtained, which, similar to the apparent exchange current, significantly depended on the cathode material: –923.1 mV (zinc cathode); +36.1 mV (copper cathode), and –603.7 mV (aluminum cathode) (AgCl/Ag). The effect of surfactants on all the kinetic parameters considered was shown. The order of the reaction with and without surfactant additives was determined. At the next stage, the electrochemical parameters of hydronium discharge on the copper electrode only were compared. It was shown that the electrochemical parameters significantly depend on the cathodic potential range where they are determined, and on the methods used for their calculation. It was noted that the process proceeds in the region of mixed kinetics. As the electrode polarization decreases, the hydrogen discharge mechanism changes, while the proportion of electrochemical kinetics will increase in the region of mixed kinetics. We suppose that the data obtained can also be of practical importance for the zinc electrolysis technology. The data obtained in this research on the electrochemical parameters of hydrogen discharge in a wide range of potentials on cathodes made of different metals as well as on the effect of electrolyte acidity on the behavior of surfactants during electrolysis will expand knowledge about the zinc electrolysis technology.
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Pratama, Affiano Akbar Nur, Ahmad Jihad, Salsabila Ainun Nisa, Ike Puji Lestari, Cornelius Satria Yudha et Agus Purwanto. « Manganese Sulphate Fertilizer Potential as Raw Material of LMR-NMC Lithium-Ion Batteries : A Review ». Materials Science Forum 1044 (27 août 2021) : 59–72. http://dx.doi.org/10.4028/www.scientific.net/msf.1044.59.
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Lithium-ion battery (Li-ion) is an energy storage device widely used in various types of electronic devices. The cathode is one of its main components, which was developed because it accelerates the transfer of electrons and battery cycle stability. Therefore, the LiNixMnyCozO2 (LNMC) cathode material, which has a discharge capacity of less than 200 mAh g−1, was further developed. Li-Mn-rich oxide cathode material (LMR-NMC) has also received considerable attention because it produces batteries with a specific capacity of more than 250 mAh g−1 at high voltages. The structure, synthesis method, and sintering temperature in the fabrication of LMR-NMC cathode materials affect battery performance. Furthermore, manganese sulphate fertilizer replaces manganese sulphate as raw material for LMR-NMC cathode due to its lower price. The method used in this study was implemented by reviewing previous literature related to Li-ion batteries, Li-ion battery cathodes, synthesis of LMR-NMC cathode materials, and the potential of manganese fertilizers. This review aims to find out the effect of structure, synthesis method, and sintering temperature on LMR-NMC cathodes made from manganese sulphate fertilizer to obtain a Li-ion battery with a high specific capacity, more environmentally friendly, has good cycle stability, and a high level of safety and lower production costs.
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Katerina Rutkovska, Hennadii Tulskyi, Valerii Homozov et Alexandr Rusinov. « SUBSTANTIATION OF TECHNOLOGICAL INDICATORS OF APPLICATION OF A GAS-DIFFUSION CATHODE IN ELECTROCHEMICAL SYNTHESIS OF HYPOCHLORITE SOLUTIONS ». Bulletin of the National Technical University "KhPI". Series : Chemistry, Chemical Technology and Ecology, no 2 (4) (28 juillet 2022) : 11–17. http://dx.doi.org/10.20998/2079-0821.2020.02.02.
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A gas diffusion electrode was used to implement depolarization of the cathodic process with atmospheric oxygen to improve the production of sodium hypochlorite by electrolysis of an aqueous solution of sodium chloride. As materials for the implementation of depolarization of the cathode process on a porous cathode from the grid, we selected: manganese oxides, cobalt oxides, ruthenium oxides. These oxides are characterized by low overvoltage of the oxygen reaction. Oxides of selected metals were applied to a mesh current lead by thermal decomposition of coating solutionsю. The gas diffusion electrode consisted of a lined titanium current lead, a dispersant of gas made of porous graphite, and an external mesh working element, on which cathodic reactions occurred. The preparation of a catalytically active layer of oxide-metal coatings was carried out by thermal decomposition of coating solutions. This method fully complies with the requirements for oxide-metal electrodes for the electrolysis of aqueous solutions of sodium chloride: the ability to control the composition of the composite coating in a wide range of component concentrations. On the current-voltage cyclic dependences of the cathodic process, for all the materials studied, certain areas of oxygen reduction and combined oxygen reduction and hydrogen evolution are observed. The first section of oxygen reduction is observed to the equilibrium potentials of the hydrogen reaction (approximately –0.42 V). The oxygen reduction rate is small and amounts to 3...5 mA/cm2. There is no difference in the current-voltage dependence due to the high potential sweep speed, which does not lead to oxygen depletion in the case of cathode operation without air supply. In the second section (at potentials, more negative equilibrium potentials of the hydrogen reaction), a significant increase in the rate of the cathodic reaction due to hydrogen evolution is observed. Oxygen, in this case, is reduced at the limiting current density. In the third section (more than –1.5 V), the speed of the cathodic process is almost completely determined by the rate of hydrogen evolution. The effect of air supply to the gas diffusion cathode is observed when comparing the reverse stroke of cyclic current–voltage dependences. On the surface of the steel mesh, an increase in the reverse current is observed in the potential range –1.0 to 0 V. Which indicates an increase in adsorbed particles involved in the cathodic process. As shown earlier, this range of potentials corresponds to the 1st and 2nd sections of the obtained dependences in which the predominant oxygen reduction occurs. Therefore, an increase in the reverse current, with potentials more positive than 1.0 V, can be explained by the effect of oxygen adsorption on the surface of gas-permeable mesh steel cathodes when air is supplied. The addition of hypochlorite ion has practically no effect on the current density in the first and second sections of the current – voltage dependences. A decrease in the cathodic current density is observed at potentials more negative from the equilibrium potential of the hydrogen reaction. This indicates a certain inhibition of the process of hydrogen evolution. In the third section, the current density also decreases. This indicates that 0.08 mol∙dm3 hypochlorite ions do not participate in cathodic reduction. Recommended current density for the studied design of the gas diffusion cathode is 15 mA/cm2 at a temperature of 291...293 K. The cathodic recovery of hypochlorite ions, under these conditions, is reduced by 55...60 %.
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Xie, Lin, et Donald Kirk. « Stability of a Fe-Rich Cathode Catalyst in an Anion Exchange Membrane Fuel Cell ». Catalysis Research 01, no 03 (9 juin 2021) : 1. http://dx.doi.org/10.21926/cr.2103003.
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Fe-rich alloys have been widely studied as catalyst materials for the cathodic oxygen reduction reaction (ORR) in hydrogen fuel cells, and many have shown high activities. The stability of Fe-rich catalysts has also been researched, and some studies have shown promising results using an accelerated stress test (AST), which uses a potential cycling method. However, for commercial fuel cell applications, such as standby power systems, the catalyst has to tolerate a high potential for a long period, which can not be represented by the AST test. In this paper, the cathode stability of a Fe-rich catalyst was studied using a standby cell potential of 0.9V, a potential shown to be challenging for the competing Pt catalysts. After 1500 hrs of testing, significant morphology changes of both the tested cathode and anode were found due to a Fe leaching process. Other alloy materials, including Ni, Cr, and Mn, were also found leached out along with the Fe species from the catalyst framework. The results are a cautionary note for using Fe based catalysts for AEMFC cathodes.
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Tremblay, Pier-Luc, Neda Faraghiparapari et Tian Zhang. « Accelerated H2 Evolution during Microbial Electrosynthesis with Sporomusa ovata ». Catalysts 9, no 2 (8 février 2019) : 166. http://dx.doi.org/10.3390/catal9020166.
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Microbial electrosynthesis (MES) is a process where bacteria acquire electrons from a cathode to convert CO2 into multicarbon compounds or methane. In MES with Sporomusa ovata as the microbial catalyst, cathode potential has often been used as a benchmark to determine whether electron uptake is hydrogen-dependent. In this study, H2 was detected by a microsensor in proximity to the cathode. With a sterile fresh medium, H2 was produced at a potential of −700 mV versus Ag/AgCl, whereas H2 was detected at −500 mV versus Ag/AgCl with cell-free spent medium from a S. ovata culture. Furthermore, H2 evolution rates were increased with potentials lower than −500 mV in the presence of cell-free spent medium in the cathode chamber. Nickel and cobalt were detected at the cathode surface after exposure to the spent medium, suggesting a possible participation of these catalytic metals in the observed faster hydrogen evolution. The results presented here show that S. ovata-induced alterations of the cathodic electrolytes of a MES reactor reduced the electrical energy required for hydrogen evolution. These observations also indicated that, even at higher cathode potentials, at least a part of the electrons coming from the electrode are transferred to S. ovata via H2 during MES.
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Payman, Adele R., et Dan M. Goebel. « Development of a 50-A heaterless hollow cathode for electric thrusters ». Review of Scientific Instruments 93, no 11 (1 novembre 2022) : 113543. http://dx.doi.org/10.1063/5.0124694.
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Hollow cathodes in electric thrusters normally use an external heater to raise the thermionic electron emitter to emission temperatures. These heaters are a potential single-point failure in the thruster and add a separate power supply to the power processing unit. Heaterless hollow cathodes are attractive for their compact size and potential higher reliability but have only been reliably demonstrated to date in small hollow cathodes capable of discharge currents below around 5 A. A new heaterless LaB6 hollow cathode has been developed that is capable of discharge currents from 5 to 50 A. The cathode configuration extends the gas feed tube at cathode potential part way into the emitting insert region of the cathode. A high-voltage Paschen discharge is struck from the tube to the keeper that heats the tube tip, which then efficiently heats the insert by radiation. This configuration eliminates the arcing observed in prior large heaterless designs that coupled the high-voltage Paschen discharge to the orifice plate or the insert itself. Discharge current–voltage characteristics show that the presence of the tube does not significantly perturb the insert-region plasma. Startup uses a simple 3 min ignition procedure, and voltage traces of the keeper discharge reveal that much of the present tube-radiator’s 100-to-150 W heating power comes from an intermediate thermionic discharge sustained by the tube during the transition between the Paschen discharge and LaB6 insert thermionic regime. This novel heating mechanism enables an unprecedented class of higher-current heaterless hollow cathodes for the next generation of high-power electric propulsion systems.
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Matos, Luís, et José Martins. « Analysis of an Educational Cathodic Protection System with a Single Drainage Point : Modeling and Experimental Validation in Aqueous Medium ». Materials 11, no 11 (25 octobre 2018) : 2099. http://dx.doi.org/10.3390/ma11112099.
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Cathodic protection, often taught in curricular units, such as corrosion and materials science, is an important subject in the study of chemical engineering. The implementation of lab setups and experimental activities in this field, are core to promoting understanding of the underlying concepts and to developing “hands-on” skills fundamental to the success of future process engineers. This paper reports the influence of different variables on the electrical potential and current behaviors of an educational cathodic protection system operated with a single drainage point. The system comprised a steel bar cathode connected to a zinc sacrificial anode, both placed in aqueous medium. The study variables were the anode area, the cathode diameter, the NaCl electrolyte concentration and the anode placement. Each variable showed a specific influence on the attenuation curves, allowing us to conclude that: (1) increasing the sacrificial anode area, or decreasing the resistivity of the medium, promotes more electronegative potentials on the structure and higher currents; (2) increasing the cathode diameter decreases the protection capacity; (3) positioning the anode in the middle of the cathode lengthwise gives rise to a more balanced potential distribution; and (4), the attenuation curves, both for potential and current, can be successfully predicted using equations based on Morgan and Uhlig’s work. High correlations were obtained between the experimental and modeling data for all the studied variables.
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Mitsushima, Shigenori, Ashraf Abdel Haleem, Kensaku Nagasawa, Yoshiyuki Kuroda, Akihiro Kato, Zaenal Awaludin, Yoshinori Nishiki et Takuto Araki. « (Invited) Leak Current Analysis of Stop Operation and Its Modeling for the Development of Bipolar Alkaline Water Electrolyzer Electrodes ». ECS Meeting Abstracts MA2022-01, no 33 (7 juillet 2022) : 1344. http://dx.doi.org/10.1149/ma2022-01331344mtgabs.
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Introduction Water electrolysis is expected a key device to introduce large-scale renewable electricity under management of power grid and electrification of non-electric sector. While alkaline water electrolysis (AWE) systems are well-developed large system, degradation under fluctuated operation with start and stop operation is significant issue to combine photovoltaic and/or wind turbine generation is significant issue. In this study, we have been investigated reverse current, which is leak current through manifold of bipolar alkaline water electrolyzers, and electrode potential behavior of stop operation, and proposed accelerated durability test (ADT) protocol for start and stop operation. Experimental and modeling Figure 1 shows configuration of 4-cells bipolar alkaline water electrolyzer that was consisted with end plates of EP(-) and EP(+), bipolar plates of BP1 to BP3, anodes, separators, and cathodes with principle of reverse current. The end and bipolar plates were made of nickel. Anodes and cathodes were commercially available oxygen and hydrogen electrocatalyst coated nickel mesh electrodes (De Nora Permelec Ltd) with 27.8 cm2 of projected area. Zirfon Perl UTP500 (Agfa) was used for separators. Manifolds were made of Teflon tubes and 15 mL/min of 7 M (= mol/dm3) was circulated for each anolyte and catholyte chambers during measurements. An anode and a cathode set on a bipolar plate. During operation anodes and cathodes are oxidized and reduces, respectively. After stop, the anode and the cathode on a bipolar plate connects both electronically and ionically, so oxidized anode and reduced cathode surface discharges to same potential. In this study, we measured electrode potential and reverse current after 1 h water electrolysis of 80oC at 0.6 A/cm2. The reverse current was measured ionic current through communicating tube with D. C. clamp meter (KEW2510, Kyoritsu). Reverse current behavior was analyzed with COMSOL Multiphysics version 5.5 based 2-dimensional model of stack and height direction using experimentally anode and cathode potentials as functions of discharge for anode and cathodes. Results and discussion Figure 2 shows cell performances in the stacks and a picture of the lab-scale zero-gap configuration electrolyzer. All cells in a stack showed almost the same performance. The cell voltage was 2 V at 400 mA/cm2 at 30oC and was 1.8 V at 500 mA/cm2 at 80oC. Therefore, we think all cells and parts work well. Figure 3 shows reverse currents and electrode potentials as a function of time after 1 h electrolysis under 600 mA/cm2 at 30 or 80 oC. Here, the dashed lines in Fig. 3-a) were simulated value and were almost same after 20 s. The measured reverse current increased around 20 s. At this moment, outlet manifolds filled with electrolyte to increase ionic conduction among the chambers, which was not considered in the simulation. After degassed of manifolds, the reverse current decreased with time with the largest reverse current for the BP2. The reverse current at 80oC was significantly larger than that at 30oC. This difference could be explained the dependence of ionic resistance of manifold on temperature. At same moment, anode and cathode potentials on the end plates were almost constant. The anode cathode potentials on the bipolar plates decreased and increased with time, respectively. Both anode and cathode showed significantly potential change region. The final potentials of all electrodes were around 0.9 V vs. RHE. The potential change regions of the electrodes on the BP2 were earlier than others. Here, the anode and cathode potentials as functions of discharge were almost same for the electrode on all bipolar plates. Therefore, the average discharge functions for anode and cathode were treated as characteristics of electrodes of this study. Using this function, reverse current as a function of time could be expressed accurately using the developed model. From this model, reverse current, and electrode potentials as a function of time would be expected with discharge function of each electrode and ionic resistance of manifold. Figure 4 shows that a start & stop operation simulated ADT protocol based on bipolar electrolyzer measurements. We propose the combination of constant current electrolysis, potential sweep, and chronoamperometry as the inset of illustration in Fig. 4, because constant current measurement is easier to get reproductivity in high current that need accurate iR correction for constant potential measurement and current control measurement never simulate stop operation. Acknowledgements This study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project (P14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO). Figure 1
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Honda, Hisashi, et Katsuhide Misono. « the Cathode fall potential of cold cathode fluorescent lamps ». JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN 73, Appendix (1989) : 8. http://dx.doi.org/10.2150/jieij1980.73.appendix_8.
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Pisciotta, John M., Zehra Zaybak, Douglas F. Call, Joo-Youn Nam et Bruce E. Logan. « Enrichment of Microbial Electrolysis Cell Biocathodes from Sediment Microbial Fuel Cell Bioanodes ». Applied and Environmental Microbiology 78, no 15 (18 mai 2012) : 5212–19. http://dx.doi.org/10.1128/aem.00480-12.
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ABSTRACTElectron-accepting (electrotrophic) biocathodes were produced by first enriching graphite fiber brush electrodes as the anodes in sediment-type microbial fuel cells (sMFCs) using two different marine sediments and then electrically inverting the anodes to function as cathodes in two-chamber bioelectrochemical systems (BESs). Electron consumption occurred at set potentials of −439 mV and −539 mV (versus the potential of a standard hydrogen electrode) but not at −339 mV in minimal media lacking organic sources of energy. Results at these different potentials were consistent with separate linear sweep voltammetry (LSV) scans that indicated enhanced activity (current consumption) below only ca. −400 mV. MFC bioanodes not originally acclimated at a set potential produced electron-accepting (electrotrophic) biocathodes, but bioanodes operated at a set potential (+11 mV) did not. CO2was removed from cathode headspace, indicating that the electrotrophic biocathodes were autotrophic. Hydrogen gas generation, followed by loss of hydrogen gas and methane production in one sample, suggested hydrogenotrophic methanogenesis. There was abundant microbial growth in the biocathode chamber, as evidenced by an increase in turbidity and the presence of microorganisms on the cathode surface. Clone library analysis of 16S rRNA genes indicated prominent sequences most similar to those ofEubacterium limosum(Butyribacterium methylotrophicum),Desulfovibriosp. A2,Rhodococcus opacus, andGemmata obscuriglobus. Transfer of the suspension to sterile cathodes made of graphite plates, carbon rods, or carbon brushes in new BESs resulted in enhanced current after 4 days, demonstrating growth by these microbial communities on a variety of cathode substrates. This report provides a simple and effective method for enriching autotrophic electrotrophs by the use of sMFCs without the need for set potentials, followed by the use of potentials more negative than −400 mV.
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Kheawhom, Soorathep, et Sira Suren. « Printed air cathode for flexible and high energy density zinc-air battery ». MRS Advances 1, no 53 (2016) : 3585–91. http://dx.doi.org/10.1557/adv.2016.443.
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ABSTRACTFlexible zinc-air batteries were fabricated using an inexpensive screen-printing technique. The anode and cathode current collectors were printed using commercial nano-silver conductive ink on a polyethylene terephthalate (PET) substrate and a polypropylene (PP) membrane, respectively. Air cathodes made of blended carbon black with inexpensive metal oxides including manganese oxide (MnO2) and cerium oxide (CeO2), were studied. The presence of the metal oxides in the air cathodes enhanced the oxygen reduction reaction which is the most important cathodic reaction in zinc-air batteries. The battery with 20 %wt CeO2showed the highest performance and provided an open-circuit voltage of 1.6 V and 5 – 240 mA.cm-2ohmic loss zone. The discharge potential of this battery at the current density of 5 mA.cm-2was nearly 0.25 V higher than that of the battery without metal oxides. Finally, the battery was tested for its flexibility by bending it so that its length decreased from 2.5 to 1 cm. The results showed that the bending did not affect characteristics on potential voltage and discharging time of the batteries fabricated.
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Włodarczyk, Barbara, et Paweł P. Włodarczyk. « Electricity Production from Yeast Wastewater in Membrane-Less Microbial Fuel Cell with Cu-Ag Cathode ». Energies 16, no 6 (15 mars 2023) : 2734. http://dx.doi.org/10.3390/en16062734.
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Wastewater has high potential as an energy source. Therefore, it is important to recover even the smallest part of this energy, e.g., in microbial fuel cells (MFCs). The obtained electricity production depends on the process rate of the electrodes. In MFC, the microorganisms are the catalyst, and the cathode is usually made of carbon material (e.g., with the addition of Pt). To increase the MFC efficiency (and reduce costs by reducing use of the noble metals), it is necessary to search the new cathode materials. In this work, the electricity production from yeast wastewater in membrane-less microbial fuel cells with Cu-Ag cathode was analyzed. In the first place, the measurements of the stationary potential of the electrodes (with Cu-Ag catalyst obtained by the electrochemical deposition technique) were performed. Because the cathode is constantly oxidized during the operation of ML-MFC, it was necessary to pre-oxidize the cathodes. Without pre-oxidation, there is a risk of changing the catalytic properties of the electrodes (along with the level of oxidation of the cathodes’ surface) throughout their operation in the ML-MFC. These measurements allowed to assess the oxidation activity of the Cu-Ag cathodes. Additionally, the influence of anodic charge on the catalytic activity of the Cu-Ag cathodes was measured. Next, the analysis of the electric energy production during the operation of the membrane-less microbial fuel cell (ML-MFC) fed by process yeast wastewater was performed. The highest parameters (the power of 6.38 mW and the cell voltage of 1.09 V) were obtained for a Cu-Ag catalyst with 5% of Ag, which was oxidized over 6 h, and after 3 anodic charges. This research proved that it is feasible to obtain the bio-electricity in the ML-MFC with Cu-Ag cathode (fed by yeast wastewater).
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Brzezinka, Tomasz L., Jeff Rao, Jose M. Paiva, Ibon Azkona, Joern Kohlscheen, German S. Fox Rabinovich, Stephen C. Veldhuis et Jose L. Endrino. « Facilitating TiB2 for Filtered Vacuum Cathodic Arc Evaporation ». Coatings 10, no 3 (6 mars 2020) : 244. http://dx.doi.org/10.3390/coatings10030244.
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TiB2 is well established as a superhard coating with a high melting point and a low coefficient of friction. The brittle nature of borides means they cannot be utilised with arc evaporation, which is commonly used for the synthesis of hard coatings as it provides a high deposition rate, fully ionised plasma and good adhesion. In this work, TiB2 conical cathodes with non-standard sintering additives (carbon and TiSi2) were produced, and the properties of the base material, such as grain structure, hardness, electrical resistivity and composition, were compared to those of monolithic TiB2. The dependence of the produced cathodes’ electrical resistivity on temperature was evaluated in a furnace with an argon atmosphere. Their arc–evaporation suitability was assessed in terms of arc mobility and stability by visual inspection and by measurements of plasma electrical potential. In addition, shaping the cathode into a cone allowed investigation of the influence of an axial magnetic field on the arc spot. The produced cathodes have a bulk hardness of 23–24 GPa. It has been found that adding 1 wt% of C ensured exceptional arc-spot stability and mobility, and requires lower arc current compared to monolithic TiB2. However, poor cathode utilization has been achieved due to the steady generation of cathode flakes. The TiB2 cathode containing 5 wt% of TiSi2 provided the best balance between arc-spot behaviour and cathode utilisation. Preventing cathode overheating has been identified as a main factor to allow high deposition rate (±1.2 µm/h) from TiB2-C and TiB2-TiSi2 cathodes.
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Horiguchi, Genki, Hihidero Kamiya et Yohei Okada. « (Digital Presentation) Development of Linear Paired Electrolysis for the Oxidation of Benzyl Alcohol ». ECS Meeting Abstracts MA2022-01, no 42 (7 juillet 2022) : 1835. http://dx.doi.org/10.1149/ma2022-01421835mtgabs.
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Electrochemical processes are always coupled reactions, with anodic oxidation and cathodic reduction. Paired electrolysis system can produce valuable products at both anode and cathode, and maximizes the efficient use of applied energy. Especially, the conversion of a single raw material to a single valuable product by paired electrolysis referred to as linear paired electrolysis. Since the electron transfers at both electrodes can produce a single valuable product in the linear paired electrolysis system, a single compound is generated with a current efficiency of 200%, theoretically. The linear paired electrolysis is appearing electrochemical process, however, it remains a challenging topic in organic electrochemical synthesis because it is complicated system. Herein, we develop the synthesis process of benzaldehyde by oxidation of benzyl alcohol using linear paired electrolysis. Electrochemical synthesis of carbonyl compounds by oxidation of alcohol is a challenging topic due to the selectivity and efficiency. We use aqueous media as the electrolyte and oxygen as the terminal oxidant to increase the selectivity and efficiency in the electrochemical transformation. Electrochemical oxidation of benzyl alcohol was performed by following method. A 4.0 mmol of tetraethylammonium perchlorate (Et4NClO4) was dissolved in 20 mL of acetonitrile (CH3CN) and 20 mL of H2O (Milli-Q water). The resultant mixture was used as an electrolyte in this study. The electrolyte was purged with O2 or Ar for 30 min, and then a 0.5 mmol of benzyl alcohol was dissolved in the electrolyte. A 20 mL of cyclohexane was added to the electrolyte to prevent overoxidation of the product. Electrolysis was conducted at room temperature with three electrodes method: a 2 cm2 of carbon felt (CF) anode, a 2 cm2 of various cathode materials, and a Ag/AgCl reference electrode. In the present study, transformation of 4-tert-butyl-benzyl alcohol (peak potential of oxidation: +1.76 V vs. Ag/AgCl) to 4-tert-butyl-benzaldehyde was used as a model reaction for optimization of reaction condition. First, we carried out constant potential electrolysis at +1.8 V vs. Ag/AgCl. Electrolysis using O2-saturated electrolyte resulted in a higher yield of the benzaldehyde (71%) than that using an Ar-saturated electrolyte (45%) when the coulomb amount was 2 F. This result suggested that O2 promoted the desired conversion. Cyclic voltammograms of the electrolyte suggested that reduction of O2 could proceed at cathode. Cathodic reduction of O2 could produce reactive oxygen species (ROS) which have strong oxidizing power. As a result, cathode in our electrochemical cell could have high oxidation potential. Therefore, it was indicated that desired oxidation progressed using ROS in our electrochemical system. In next step, we conducted electrochemical reactions under constant potential electrolysis at −0.7 V vs. Ag/AgCl which was suitable for the reduction of O2. In this condition, benzaldehyde was obtained in 86% yield when the coulomb amount was 2 F, and no byproduct was observed. From this result, we proposed the indirect oxidation pass using ROS generated at cathode. Interestingly, when the cathode (working electrode) was set to −0.7 V vs. Ag/AgCl, the measured potential of the anode (counter electrode) was +1.5 to +1.8 V vs. Ag/AgCl. Therefore, when the reduction of O2 proceeded at cathode, potential of anode reached sufficient value to oxidize the benzyl alcohol. It meant both direct oxidation and indirect oxidation progressed in a single electrochemical cell. It was linear paired electrolysis system of oxidation of benzyl alcohol. We considered the reaction on cathode was important to progress desired oxidation, and the effect of different cathode materials was also investigated. In this investigation, carbon felt, glassy carbon, Pt, and Ni could be used as cathodes in the linear paired electrolysis system. In contrast, a sharp decrease in current was observed immediately after the start of electrolysis using Al as the cathode. Observation and analysis of the used Al electrodes suggested that surface of Al cathodes was passivated. It was indicated that electrochemically generated ROS with high oxidizing power might promote the passivation of the cathode materials. The observed passivation also supported the generation of ROS at cathode in our electrochemical cells. Finally, we demonstrated the versatility of developed linear paired electrolysis with various benzyl alcohols. Especially, 4-Methoxybenzaldehyde was not only obtained in high yields (94%) but also with maximum current efficiencies of 146%. The exceeding 100% current efficiency also supported the linear paired electrolysis system. In summary, we successfully developed a process for oxidation of benzyl alcohols via linear paired electrolysis with high selectivity and efficiency. Since desired reaction progressed both electrodes and aqueous media and O2 were used, this system offered green and sustainable chemical synthesis process. Figure 1
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Sui, Dong, Meijia Chang, Zexin Peng, Changle Li, Xiaotong He, Yanliang Yang, Yong Liu et Yanhong Lu. « Graphene-Based Cathode Materials for Lithium-Ion Capacitors : A Review ». Nanomaterials 11, no 10 (19 octobre 2021) : 2771. http://dx.doi.org/10.3390/nano11102771.
Texte intégralRésumé :
Lithium-ion capacitors (LICs) are attracting increasing attention because of their potential to bridge the electrochemical performance gap between batteries and supercapacitors. However, the commercial application of current LICs is still impeded by their inferior energy density, which is mainly due to the low capacity of the cathode. Therefore, tremendous efforts have been made in developing novel cathode materials with high capacity and excellent rate capability. Graphene-based nanomaterials have been recognized as one of the most promising cathodes for LICs due to their unique properties, and exciting progress has been achieved. Herein, in this review, the recent advances of graphene-based cathode materials for LICs are systematically summarized. Especially, the synthesis method, structure characterization and electrochemical performance of various graphene-based cathodes are comprehensively discussed and compared. Furthermore, their merits and limitations are also emphasized. Finally, a summary and outlook are presented to highlight some challenges of graphene-based cathode materials in the future applications of LICs.
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Hayashi, Hideki, Shien-Fong Lin, Boyoung Joung, Hrayr S. Karagueuzian, James N. Weiss et Peng-Sheng Chen. « Virtual electrodes and the induction of fibrillation in Langendorff-perfused rabbit ventricles : the role of intracellular calcium ». American Journal of Physiology-Heart and Circulatory Physiology 295, no 4 (octobre 2008) : H1422—H1428. http://dx.doi.org/10.1152/ajpheart.00001.2008.
Texte intégralRésumé :
A strong premature electrical stimulus (S2) induces both virtual anodes and virtual cathodes. The effects of virtual electrodes on intracellular Ca2+ concentration ([Ca2+]i) transients and ventricular fibrillation thresholds (VFTs) are unclear. We studied 16 isolated, Langendorff-perfused rabbit hearts with simultaneous voltage and [Ca2+]i optical mapping and for vulnerable window determination. After baseline pacing (S1), a monophasic (10 ms anodal or cathodal) or biphasic (5 ms-5 ms) S2 was applied to the left ventricular epicardium. Virtual electrode polarizations and [Ca2+]i varied depending on the S2 polarity. Relative to the level of [Ca2+]i during the S1 beat, the [Ca2+]i level 40 ms after the onset of monophasic S2 increased by 36 ± 8% at virtual anodes and 20 ± 5% at virtual cathodes ( P < 0.01), compared with 25 ± 5% at both virtual cathode-anode and anode-cathode sites for biphasic S2. The VFT was significantly higher and the vulnerable window significantly narrower for biphasic S2 than for either anodal or cathodal S2 ( n = 7, P < 0.01). Treatment with thapsigargin and ryanodine ( n = 6) significantly prolonged the action potential duration compared with control (255 ± 22 vs. 189 ± 6 ms, P < 0.05) and eliminated the difference in VFT between monophasic and biphasic S2, although VFT was lower for both cases. We conclude that virtual anodes caused a greater increase in [Ca2+]i than virtual cathodes. Monophasic S2 is associated with lower VFT than biphasic S2, but this difference was eliminated by the inhibition of the sarcoplasmic reticulum function and the prolongation of the action potential duration. However, the inhibition of the sarcoplasmic reticulum function also reduced VFT, indicating that the [Ca2+]i dynamics modulate, but are not essential, to ventricular vulnerability.
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Li, Rui Feng, Shou Cheng He et Lu Cun Guo. « Effect of Ce0.8Sm0.2O1.9 Interlayer on the Electrochemical Performance of LaBaCo2O5+δ Cathode for IT-SOFCs ». Applied Mechanics and Materials 423-426 (septembre 2013) : 532–36. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.532.
Texte intégralRésumé :
The Ce0.8Sm0.2O1.9(SDC) interlayer was prepared by screen-printing method between LaBaCo2O5+δ(LBCO) cathode and 8YSZ electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The effect of SDC interlayer on the electrochemical performance of LBCO cathode was investigated. Experimental results showed that the LBCO cathode with SDC interlayer showed much lower area-specific resistance (ASR) and polarization overpotential than that of LBCO cathode without SDC interlayer at the same test condition, exhibiting the better electrochemical performance. For LBCO cathode with SDC interlayer, the ASR was 0.457 Ωcm2at 800 °C in air, about 36.2 % lower than that of the LBCO cathode without SDC interlayer, and the cathodic overpotential was reduced by 38.0 % at a current density of 0.02 Acm-2at 700 °C in air. The application of a thin-layer SDC interlayer between cathode and dense 8YSZ electrolyte showed great potential in improving the cathode performance for IT-SOFCs.
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Peters, Jens, Alexandra Peña Cruz et Marcel Weil. « Exploring the Economic Potential of Sodium-Ion Batteries ». Batteries 5, no 1 (16 janvier 2019) : 10. http://dx.doi.org/10.3390/batteries5010010.
Texte intégralRésumé :
Sodium-ion batteries (SIBs) are a recent development being promoted repeatedly as an economically promising alternative to lithium-ion batteries (LIBs). However, only one detailed study about material costs has yet been published for this battery type. This paper presents the first detailed economic assessment of 18,650-type SIB cells with a layered oxide cathode and a hard carbon anode, based on existing datasheets for pre-commercial battery cells. The results are compared with those of competing LIB cells, that is, with lithium-nickel-manganese-cobalt-oxide cathodes (NMC) and with lithium-iron-phosphate cathodes (LFP). A sensitivity analysis further evaluates the influence of varying raw material prices on the results. For the SIB, a cell price of 223 €/kWh is obtained, compared to 229 €/kWh for the LFP and 168 €/kWh for the NMC batteries. The main contributor to the price of the SIB cells are the material costs, above all the cathode and anode active materials. For this reason, the amount of cathode active material (e.g., coating thickness) in addition to potential fluctuations in the raw material prices have a considerable effect on the price per kWh of storage capacity. Regarding the anode, the precursor material costs have a significant influence on the hard carbon cost, and thus on the final price of the SIB cell. Organic wastes and fossil coke precursor materials have the potential of yielding hard carbon at very competitive costs. In addition, cost reductions in comparison with LIBs are achieved for the current collectors, since SIBs also allow the use of aluminum instead of copper on the anode side. For the electrolyte, the substitution of lithium with sodium leads to only a marginal cost decrease from 16.1 to 15.8 €/L, hardly noticeable in the final cell price. On the other hand, the achievable energy density is fundamental. While it seems difficult to achieve the same price per kWh as high energy density NMC LIBs, the SIB could be a promising substitute for LFP cells in stationary applications, if it also becomes competitive with LFP cells in terms of safety and cycle life.
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Subardi, A., et Y. P. Fu. « Structural, particle size distribution, and electrochemical behavior of double perovskite oxide doped Ce0.8Sm0.2O1.9 for intermediate temperature solid oxide fuel cells ». IOP Conference Series : Earth and Environmental Science 1151, no 1 (1 mars 2023) : 012051. http://dx.doi.org/10.1088/1755-1315/1151/1/012051.
Texte intégralRésumé :
Abstract Double perovskite SmBa0.5Sr0.5Co2O5+δ(70%)+Ce0.8Sm0.2O1.9(30%) as SBSC70+SDC30 cathode was fabricated using solid-state reaction technique and investigated as cathode material for solid oxide fuel cells operating at intermediate temperature (IT-SOFC). This work aims to determine the effect of SDC electrolyte doping into double perovskite cathodes on SOFC performance. LS-POP carried out particle size distribution analysis, and the equipment operates on a light source (HE-Ne laser) basis. XRD was used to determine the structure of the cathode powder, and SEM was used to analyze the microstructure morphology. Symmetrical cells were tested using a potentiostat Voltalab PGZ 301. The distribution of particle size for the SBSC70+SDC30 cathode was in the range of 1.41-2.03 µm. The polarization resistance (Rp) value of SBSC70+SDC30 cathode decreases with increasing temperature from 1.22 cm2 at 600°C to 0.21 cm2 at 800°C. The SBSC70+SDC30 activation energy (Ea) for Rp was 117. 3 kJ mol−1. From the overall results, double perovskite SBSC70+SDC30 cathode has potential as a cathode of medium temperature SOFC cells.
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Lukovych, V. V. « On the pipeline polarization in the case of insulation delamination from its surface ». Uspihi materialoznavstva 2020, no 1 (1 décembre 2020) : 40–45. http://dx.doi.org/10.15407/materials2020.01.040.
Texte intégralRésumé :
The cathodic protection parameters for two pipelines with a diameter of 1420 mm were calculated. The protection zone for the first pipeline is 6 km long and for the second one it is 5 km. The cathode station current is 12,9 A for the first pipeline and 4 A for the second one. There are a damage and detachment of pipeline insulation, andconsequently a thin layer of electrolyte is located in the detachment area between the metal surface and the insulation. Almost the entire surface of the pipeline has polarization potential. For the first pipeline, the values of the protection potential at neighboring measurement points change quite dramatically, the difference between them can reach tenths of a volt. The polarization current density at the ends of the protection zone is quite small, and accordingly the polarization potential is close to the corrosion potential. But in the vicinity of the drainage point, these values are much larger. The situation is almost the opposite for the second pipeline, where the cathode station current is 4 A. The current density is almost equally distributed throughout the protection zone, slightly larger at its ends. The polarization potential changes accordingly. Its values are larger than the first case. In the cathodic protection, the potential of the pipeline relative to ground zero is important. Its average value depends on the magnitude of the cathode station current. Its graph intersects the lower part of the protection potential graph in the first case and the middle of the graph in the second. The protection potential is the difference between the potential of the pipeline and the earth surface. In the first case, in the vicinity of the drainage point this difference is much larger inside compared to the ends of the zone. As a conclusion, in the practice of cathodic protection it is important to regulate the value of the cathode station current in order to achieve the optimum protection. Keywords: delamination, protection potential, polarization current density.
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Kuntyi, Оrest, Galyna Zozulya et Mariana Shepida. « CO2 Electroreduction in Organic Aprotic Solvents : A Mini Review ». Journal of Chemistry 2022 (31 juillet 2022) : 1–12. http://dx.doi.org/10.1155/2022/1306688.
Texte intégralRésumé :
An annual increase of CO2 concentrations in the atmosphere causes global environmental problems, addressed by systematic research to develop effective technologies for capturing and utilizing carbon dioxide. Electrochemical catalytic reduction is one of the effective directions of CO2 conversion into valuable chemicals and fuels. The electrochemical conversion of CO2 at catalytically active electrodes in aqueous solutions is the most studied. However, the problems of low selectivity for target products and hydrogen evolution are unresolved. Literature sources on CO2 reduction at catalytically active cathodes in nonaqueous mediums, particularly in organic aprotic solvents, are analyzed in this article. Two directions of cathodic reduction of CO2 are considered—nonaqueous organic aprotic solvents and organic aprotic solvents containing water. The current interpretation of the cathodic conversion mechanism of carbon (IV) oxide into CO and organic products and the main factors influencing the rate of CO2 reduction, Faradaic efficiency of conversion products, and the ratio of direct cathodic reduction of CO2 are given. The influence of the nature of organic aprotic solvent is analyzed, including the topography of the catalytically active cathode, values of cathode potential, and temperature. Emphasis is placed on the role of water impurities in reducing CO2 electroreduction overpotentials and the formation of new CO2 conversion products, including formate and H2.
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Luo, Shiqiang, Shiwei Liu, Guoshen Yang, Yinghao Xie, Pritesh Hiralal, Zanxiang Nie, Gehan A. J. Amaratunga et Hang Zhou. « A thin flexible zinc battery enabled by simultaneously electro-depositing both electrodes in acetate electrolytes ». Journal of Physics : Conference Series 2552, no 1 (1 juillet 2023) : 012001. http://dx.doi.org/10.1088/1742-6596/2552/1/012001.
Texte intégralRésumé :
Abstract Electrolytic batteries with the anode or cathode formed by electro-deposition from the electrolytes show promising potential for simplifying the fabrication process of flexible and micro-size rechargeable batteries. Thin flexible zinc batteries with both anode and cathode electro-deposited simultaneously are demonstrated and investigated here. We find that the acetate anions (Ac-) show excellent electro-depositing efficiency for manganese oxide cathodes, which enable a capacity of 0.26 mAh/cm2 with only carbon current collectors and electrolytes.
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Park, Nam-Yung, Jae-Min Kim et Yang-Kook Sun. « Advanced Concentration Gradient Cathode Material for Next-Generation Electric Vehicles ». ECS Meeting Abstracts MA2022-02, no 3 (9 octobre 2022) : 324. http://dx.doi.org/10.1149/ma2022-023324mtgabs.
Texte intégralRésumé :
With the prevalence of electric vehicles (EVs), the use of Li-ion batteries (LIBs) in EVs presents a new set of challenges such as cost, charging behavior, driving range per charge, risk of thermal runaway, and battery life. As the performance of LIBs is largely determined by the cathode material, the development of high-performance LIBs for EVs has focused on increasing the capacity of the cathode by using Ni-rich Li[NixCoyAl1−x−y]O2 (NCA) and Li[NixCoyMn1−x−y]O2 (NCM) cathodes.1 Ni-rich core encapsulated by a shell with concentration gradients (CSG) is the only field-proven strategy that is able to tap the potential capacity of Ni-rich cathodes while providing long cycle life.2 Despite the success of CSG cathodes, concentration gradients in the hydroxide precursor are intrinsically unstable and susceptible to flattening through interdiffusion during lithiation process.3 Furthermore, excessive coarsening during lithiation destroys the aligned microstructure, which undermines the mechanical stability of the cathode against microcrack formation.3 Therefore, CSG cathodes require a narrow processing temperature window; however, this increases their manufacturing cost. Herein, it was demonstrated that the doping of a CSG cathode with an average composition of Li[Ni0.9Co0.5Mn0.5]O2 with 0.5 mol% Sb substantially improved its cycling stability while providing manufacturing flexibility. Sb doping allowed precise tailoring of the cathode microstructure through the retardation of cation migration and the inhibition of coarsening by pinning particle boundaries. The Sb-doped CSG cathode retained ~80% of its initial capacity for 2500 cycles, while the pristine CSG90 cathode showed similar capacitive deterioration over only 1500 cycles. The proposed Sb-doped CSG90 cathode for use in electric vehicles represents an ideal high-energy-density cathode with a composition engineered to maximize capacity; its modified microstructure ensures a long battery life and ease of manufacturing, enabling cost reduction. Reference s : [1] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources, 2013, 233, 121. [2] U.-H. Kim, H.-H. Ryu, J.-H. Kim, R. Mucke, P. Kaghazchi, C. S. Yoon, Y.-K. Sun, Adv. Energy Mater. 2019, 9, 1803902. [3] G.-T. Park, H.-H Ryu, T.-C. Noh, G.-C. Kang, Y.-K. Sun, Mater. Today, 2022, 52, 9.
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Bi, Yujing, Jinhui Tao, Yuqin Wu, Linze Li, Yaobin Xu, Enyuan Hu, Bingbin Wu et al. « Reversible planar gliding and microcracking in a single-crystalline Ni-rich cathode ». Science 370, no 6522 (10 décembre 2020) : 1313–17. http://dx.doi.org/10.1126/science.abc3167.
Texte intégralRésumé :
High-energy nickel (Ni)–rich cathode will play a key role in advanced lithium (Li)–ion batteries, but it suffers from moisture sensitivity, side reactions, and gas generation. Single-crystalline Ni-rich cathode has a great potential to address the challenges present in its polycrystalline counterpart by reducing phase boundaries and materials surfaces. However, synthesis of high-performance single-crystalline Ni-rich cathode is very challenging, notwithstanding a fundamental linkage between overpotential, microstructure, and electrochemical behaviors in single-crystalline Ni-rich cathodes. We observe reversible planar gliding and microcracking along the (003) plane in a single-crystalline Ni-rich cathode. The reversible formation of microstructure defects is correlated with the localized stresses induced by a concentration gradient of Li atoms in the lattice, providing clues to mitigate particle fracture from synthesis modifications.
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Chen, Long, Ameet Pinto et Akram N. Alshawabkeh. « Activated Carbon as a Cathode for Water Disinfection through the Electro-Fenton Process ». Catalysts 9, no 7 (12 juillet 2019) : 601. http://dx.doi.org/10.3390/catal9070601.
Texte intégralRésumé :
Unlike many other water disinfection methods, hydroxyl radicals (HO•) produced by the Fenton reaction (Fe2+/H2O2) can inactivate pathogens regardless of taxonomic identity of genetic potential and do not generate halogenated disinfection by-products. Hydrogen peroxide (H2O2) required for the process is typically electrogenerated using various carbonaceous materials as cathodes. However, high costs and necessary modifications to the cathodes still present a challenge to large-scale implementation. In this work, we use granular activated carbon (GAC) as a cathode to generate H2O2 for water disinfection through the electro-Fenton process. GAC is a low-cost amorphous carbon with abundant oxygen- and carbon-containing groups that are favored for oxygen reduction into H2O2. Results indicate that H2O2 production at the GAC cathode is higher with more GAC, lower pH, and smaller reactor volume. Through the addition of iron ions, the electrogenerated H2O2 is transformed into HO• that efficiently inactivated model pathogen (Escherichia coli) under various water chemistry conditions. Chick–Watson modeling results further showed the strong lethality of produced HO• from the electro-Fenton process. This inactivation coupled with high H2O2 yield, excellent reusability, and relatively low cost of GAC proves that GAC is a promising cathodic material for large-scale water disinfection.
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Nguyen, Thang Phan, et Il Tae Kim. « Iron-Vanadium Incorporated Ferrocyanides as Potential Cathode Materials for Application in Sodium-Ion Batteries ». Micromachines 14, no 3 (23 février 2023) : 521. http://dx.doi.org/10.3390/mi14030521.
Texte intégralRésumé :
Sodium-ion batteries (SIBs) are potential replacements for lithium-ion batteries owing to their comparable energy density and the abundance of sodium. However, the low potential and low stability of their cathode materials have prevented their commercialization. Prussian blue analogs are ideal cathode materials for SIBs owing to the numerous diffusion channels in their 3D structure and their high potential vs. Na/Na+. In this study, we fabricated various Fe-V-incorporated hexacyanoferrates, which are Prussian blue analogs, via a one-step synthesis. These compounds changed their colors from blue to green to yellow with increasing amounts of incorporated V ions. The X-ray photoelectron spectroscopy spectrum revealed that V3+ was oxidized to V4+ in the cubic Prussian blue structure, which enhanced the electrochemical stability and increased the voltage platform. The vanadium ferrocyanide Prussian blue (VFPB1) electrode, which contains V4+ and Fe2+ in the Prussian blue structure, showed Na insertion/extraction potential of 3.26/3.65 V vs. Na/Na+. The cycling test revealed a stable capacity of ~70 mAh g–1 at a rate of 50 mA g–1 and a capacity retention of 82.5% after 100 cycles. We believe that this Fe-V-incorporated Prussian green cathode material is a promising candidate for stable and high-voltage cathodes for SIBs.
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Bazzoni, B., S. Lorenzi, P. Marcassoli et T. Pastore. « Current and Potential Distribution Modeling for Cathodic Protection of Tank Bottoms ». Corrosion 67, no 2 (1 février 2011) : 026001–1. http://dx.doi.org/10.5006/1.3553930.
Texte intégralRésumé :
Abstract Aboveground tanks for the storage of liquid hydrocarbon are often erected with a secondary containment membrane installed below the tank bottom to prevent soil contamination in case of leakage. The design of impressed current cathodic protection in the presence of the plastic membrane is based on distributed anodes installed in the space between the tank bottom and the membrane; among available anodes, the most commonly used are the titanium grid or ribbon activated with noble metal oxides. The configuration of the grid or ribbon anode system confined in the closed space between the bottom and membrane creates specific issues concerning the electrochemical reactions occurring at the anode and cathode, the ohmic drops in the anode system, and the potential and current distribution at the cathode. Results of a number of numeric simulations performed to predict the actual distribution of current and potential are given. Design criteria are discussed.
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Bitenc, Jan, Tjaša Pavčnik, Urban Košir et Klemen Pirnat. « Quinone Based Materials as Renewable High Energy Density Cathode Materials for Rechargeable Magnesium Batteries ». Materials 13, no 3 (21 janvier 2020) : 506. http://dx.doi.org/10.3390/ma13030506.
Texte intégralRésumé :
Organic cathode materials are promising cathode materials for multivalent batteries. Among organic cathodes, anthraquinone (AQ) has already been applied to various metal‒organic systems. In this work, we compare electrochemical performance and redox potential of AQ with 1,4-naphthoquinone (NQ) and 1,4-benzoquinone (BQ), both of which offer significantly higher theoretical energy density than AQ and are tested in two different Mg electrolytes. In Mg(TFSI)2-2MgCl2 electrolyte, NQ and BQ exhibit 0.2 and 0.5 V higher potential than AQ, respectively. Furthermore, an upshift of potential for 200 mV in MgCl2-AlCl3 electrolyte versus Mg(TFSI)2-2MgCl2 was confirmed for all used organic compounds. While lower molecular weights of NQ and BQ increase their specific capacity, they also affect the solubility in used electrolytes. Increased solubility lowers long-term capacity retention, confirming the need for the synthesis of NQ and BQ based polymers. Finally, we examine the electrochemical mechanism through ex situ attenuated total reflectance infrared spectroscopy (ATR-IR) and comparison of ex situ cathode spectra with spectra of individual electrode components. For the first time, magnesium anthracene-9,10-bis(olate), a discharged form of AQ moiety, is synthesized, which allows us to confirm the electrochemical mechanism of AQ cathode in Mg battery system.
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Xia, Yang, Zheng Fang, Chengwei Lu, Zhen Xiao, Xinping He, Yongping Gan, Hui Huang, Guoguang Wang et Wenkui Zhang. « A Facile Pre-Lithiated Strategy towards High-Performance Li2Se-LiTiO2 Composite Cathode for Li-Se Batteries ». Nanomaterials 12, no 5 (28 février 2022) : 815. http://dx.doi.org/10.3390/nano12050815.
Texte intégralRésumé :
Conventional lithium-ion batteries with a limited energy density are unable to assume the responsibility of energy-structure innovation. Lithium-selenium (Li-Se) batteries are considered to be the next generation energy storage devices since Se cathodes have high volumetric energy density. However, the shuttle effect and volume expansion of Se cathodes severely restrict the commercialization of Li-Se batteries. Herein, a facile solid-phase synthesis method is successfully developed to fabricate novel pre-lithiated Li2Se-LiTiO2 composite cathode materials. Impressively, the rationally designed Li2Se-LiTiO2 composites demonstrate significantly enhanced electrochemical performance. On the one hand, the overpotential of Li2Se-LiTiO2 cathode extremely decreases from 2.93 V to 2.15 V. On the other hand, the specific discharge capacity of Li2Se-LiTiO2 cathode is two times higher than that of Li2Se. Such enhancement is mainly accounted to the emergence of oxygen vacancies during the conversion of Ti4+ into Ti3+, as well as the strong chemisorption of LiTiO2 particles for polyselenides. This facile pre-lithiated strategy underscores the potential importance of embedding Li into Se for boosting electrochemical performance of Se cathode, which is highly expected for high-performance Li-Se batteries to cover a wide range of practical applications.
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Alikin, Denis, Boris Slautin et Andrei Kholkin. « Revealing Lithiation Kinetics and Battery Degradation Pathway in LiMn2O4-Based Commercial Cathodes via Electrochemical Strain Microscopy ». Batteries 8, no 11 (5 novembre 2022) : 220. http://dx.doi.org/10.3390/batteries8110220.
Texte intégralRésumé :
The capacity fade during the cycling of lithium batteries is a key factor limiting further progress in the improvement of electric vehicles, wearable electronic devices, alternative energy sources, etc. One of the main reasons for capacity loss is battery cathode degradation, which significantly influences the battery lifetime. Despite in-depth knowledge of battery degradation at the chemical level, the kinetics of the degradation at the resolution of the individual elements of the cathode are not fully understood. Here, we studied lithiation kinetics in commercial cathodes based on lithium manganese spinel using the electrochemical strain microscopy local method. Supported by the experimental finding, the “viscous fingers” model of lithium ions intercalation–deintercalation in individual particles of the cathode was proposed. The non-linear dynamics of the lithiation front were suggested to be stimulated by the non-uniform stress field and gradient of the chemical potential. Irregularity of the lithiation front causes the formation of the residual lithiated pocket in the delithiated particles, which effectively reduces the volume available for chemical reaction. The obtained results shed further light on the degradation of the lithium battery cathodes and can be applicable for other cathode materials.
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Fonna, Syarizal, Syifaul Huzni, Muzaiyin Arika Putra et Rudi Kurniawan. « Simulation the effect of anode-cathode displacement and anode type on reinforced concrete cathodic protection using BEM ». MATEC Web of Conferences 197 (2018) : 12001. http://dx.doi.org/10.1051/matecconf/201819712001.
Texte intégralRésumé :
The aim of the study is to simulate the effect of anode-cathode displacement and anode type on the potential distribution of reinforced concrete (RC) cathodic protection (CP) system using boundary element method (BEM). For the simulation, Laplace equation was used to model the RC domain. The boundary conditions for the anode and cathode (reinforcing steel/rebar) were represented by its polarization curve. By using BEM, the electrical potential values on the whole domain should be calculated. Therefore, the effects of those parameters were studied based on the rebar electrical potential. For the study, the CP system model and geometry were obtained from a previous researcher. The BEM simulation results show that the anode-cathode displacement affects the distribution of electrical potential on the protected reinforcing steel. It was consistent with the previous research result. The results also show, as expected, that the anode type influences the electrical potential value on the rebar. Hence, those parameters should be considered in designing and/or evaluating the RC CP system.
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Liu, Baishan. « Transition Metal Dichalcogenides for High−Performance Aqueous Zinc Ion Batteries ». Batteries 8, no 7 (29 juin 2022) : 62. http://dx.doi.org/10.3390/batteries8070062.
Texte intégralRésumé :
Aqueous zinc ion batteries (ZIBs) with cost—effectiveness, air stability, and remarkable energy density have attracted increasing attention for potential energy storage system applications. The unique electrical properties and competitive layer spacing of transition metal dichalcogenides (TMDs) provide dramatical freedom for facilitating ion diffusion and intercalation, making TMDs suitable for ZIB cathode materials. The recently updated advance of TMDs for high−performance ZIB cathode materials have been summarized in this review. In particular, the key modification strategies of TMDs for realizing the full potential in ZIBs are highlighted. Finally, the insights for further development of TMDs as ZIB cathodes are proposed, to guide the research directions related to the design of aqueous ZIBs while approaching the theoretical performance metrics.
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Aliotta, Chiara, Maria Costa, Leonarda Francesca Liotta, Valeria La Parola, Giuliana Magnacca et Francesca Deganello. « Peculiar Properties of the La0.25Ba0.25Sr0.5Co0.8Fe0.2O3−δ Perovskite as Oxygen Reduction Electrocatalyst ». Molecules 28, no 4 (8 février 2023) : 1621. http://dx.doi.org/10.3390/molecules28041621.
Texte intégralRésumé :
The electrochemical reduction of molecular oxygen is a fundamental process in Solid Oxide Fuel Cells and requires high efficiency cathode materials. Two La0.25Ba0.25Sr0.5Co0.8Fe0.2O3−δ-based perovskite compounds were prepared by solution combustion synthesis, and characterized for their structural, microstructural, surface, redox and electrochemical properties as potential cathodes in comparison with Ba0.5Sr0.5Co0.8Fe0.2O3−δ and La0.5Sr0.5Co0.8Fe0.2O3−δ perovskites. Results highlighted that calcination at 900 °C led to a “bi-perovskite heterostructure”, where two different perovskite structures coexist, whereas at higher calcination temperatures a single-phase perovskite was formed. The results showed the effectiveness of the preparation procedures in co-doping the A-site of perovskites with barium and lanthanum as a strategy to optimize the cathode’s properties. The formation of nanometric heterostructure co-doped in the A-site evidenced an improvement in oxygen vacancies’ availability and in the redox properties, which promoted both processes: oxygen adsorption and oxygen ions drift, through the cathode material, to the electrolyte. A reduction in the total resistance was observed in the case of heterostructured material.
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Wang, Lifan, Qinling Shi, Chun Zhan et Guicheng Liu. « One-Step Solid-State Synthesis of Ni-Rich Cathode Materials for Lithium-Ion Batteries ». Materials 16, no 8 (13 avril 2023) : 3079. http://dx.doi.org/10.3390/ma16083079.
Texte intégralRésumé :
Ni-rich cathodes are expected to serve as critical materials for high-energy lithium-ion batteries. Increasing the Ni content can effectively improve the energy density but usually leads to more complex synthesis conditions, thus limiting its development. In this work, a simple one-step solid-state process for synthesizing Ni-rich ternary cathode materials NCA (LiNi0.9Co0.05Al0.05O2) was presented, and the synthesis conditions were systematically studied. It was found that the synthesis conditions have a substantial impact on electrochemical performance. Furthermore, the cathode materials produced through a one-step solid-state process exhibited excellent cycling stability, maintaining 97.2% of their capacity after 100 cycles at a rate of 1 C. The results show that a one-step solid-state method can successfully synthesize Ni-rich ternary cathode material, which has great potential for application. Optimizing the synthesis conditions also provides valuable ideas for the commercial synthesis of Ni-rich cathode materials.
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Wang, Zhuo, et Guosheng Shao. « High-capacity cathodes for magnesium lithium chlorine tri-ion batteries through chloride intercalation in layered MoS2 : a computational study ». Journal of Materials Chemistry A 6, no 16 (2018) : 6830–39. http://dx.doi.org/10.1039/c8ta01050a.
Texte intégralRésumé :
Rechargeable magnesium ion batteries (MIBs) have great potential as an alternative technology to substitute resource-limited lithium-ion batteries (LIBs), but rather difficult transportation of Mg2+ in cathodes and hence low cathode capacities loom as a major roadblock for their applications.
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Zhang, Long, et Yongchang Liu. « Aqueous Zinc–Chalcogen Batteries : Emerging Conversion-Type Energy Storage Systems ». Batteries 9, no 1 (16 janvier 2023) : 62. http://dx.doi.org/10.3390/batteries9010062.
Texte intégralRésumé :
Aqueous zinc (Zn) metal batteries are considered competitive candidates for next-generation energy storage, attributed to the abundance, low redox potential, and high theoretical capacity of Zn. However, conventional cathode materials are mainly based on ion-insertion electrochemistry, which can only deliver limited capacity. The conversion-type aqueous zinc–chalcogen batteries (AZCBs) have received widespread attention because they combine the advantages of chalcogen cathodes (S, Se, and Te) and Zn anodes to significantly enhance their capacity. Research on AZCBs has increased continuously; however, it is still in its infancy because the selection and regulation of cathode material systems are not comprehensive and systematic, and the investigation of the mechanisms is not thorough. Herein, we present a detailed overview explaining the recent progress of AZCBs, providing comprehensive guidelines for further research. First, research based on S cathodes, which is the most studied system among AZCBs, is summarized. Second, research based on Se and Te cathodes is described. Research on these different systems is mainly focused on electrolyte modification and cathode optimization. In each section, various strategies are introduced, and the working mechanisms are also discussed. Finally, the challenges and prospects for the development of AZCBs are presented.
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JACOBY, MITCH. « New battery cathode packs higher potential ». Chemical & ; Engineering News 76, no 16 (20 avril 1998) : 12. http://dx.doi.org/10.1021/cen-v076n016.p012.
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Kulentsan, Anton L., Dmitriy A. Shutov et Vladimir V. Rybkin. « IMPACT OF TRANSFER PROCESSES OF LIQIUD CATHODE COMPONENTS ON PHYSICAL-CHEMICAL PARAMETERS OF ATMOSPHERIC PRESSURE DC DISCHARGE ». IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no 6 (19 juillet 2017) : 52. http://dx.doi.org/10.6060/tcct.2017606.5566.
Texte intégralRésumé :
Experimental data on glow discharge parameters of atmospheric pressure in air with cathodes from distilled water and water containing ions of potassium, sodium and copper (II) are obtained. Chlorides of the corresponding salts were used. The current range was 20-60 mA, and the solution concentrations were -0.1-0.4 mol/l. The cathode drops of the potential and the electric fields in the plasma are determined by the mobile anode method. With emission spectroscopy by modeling the unresolved rotational structure of the emission bands of the second positive system of nitrogen molecules, gas temperatures were found. On the basis of these data, the total concentrations of the particles, the reduced electric field strengths, were found. It is found that the increase in the discharge current leads to a decrease in the cathode drops of the potential, the strengths of the electric fields, and the reduced field strengths. At the same time, the temperature of the gas was practically independent on the discharge current and it was 1600 ± 150 K. By numerical solution of the Boltzmann equation for electrons, electron energy distribution functions, mean energies and electron concentrations and rate constants of the processes occurring under the action of electron impact were determined. An estimate is made of the contribution to the formation of charged particles in the plasma of ionization processes of metal atoms that appear in the gas phase as a result of non-equilibrium transfer from the liquid cathode. It is shown that for molar fractions of metal atoms of 10-4 and higher, ionization is completely determined by collisions of electrons with metal atoms, rather than with molecules of the main plasma-forming gas. It is also shown that discharges with cathodes containing salt solutions have smaller values of cathode potential drops.Forcitation:Kuletsan A.L., Shutov D.A., Rybkin V.V. Impact of transfer processes of liqiud cathode components on physical-chemical parameters of atmospheric pressure dc discharge. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 52-58.
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Weret, Misganaw Adigo, Wei-Nien Su et Bing-Joe Hwang. « Organosulfur Cathodes with High Compatibility in Carbonate Ester Electrolytes for Long Cycle Lithium–Sulfur Batteries ». ECS Meeting Abstracts MA2022-02, no 4 (9 octobre 2022) : 536. http://dx.doi.org/10.1149/ma2022-024536mtgabs.
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Lithium-sulfur batteries (LSBs) are potential candidates for high energy storage technologies due to their theoretical gravimetric energy density of ∼2600 Wh kg-1 and lightweight electrodes. In LSBs, ether electrolytes are frequently utilized because sulfur cathodes and the polysulfide redox intermediate species are chemically stable. However, LSBs in ether electrolytes suffer from the dissolution of higher-order polysulfides, and migration of the soluble polysulfides into electrolytes causes the polysulfide shuttle effect. The shuttle polysulfides react with the lithium anode and give rise to the irreversible deposition of lithium sulfides, deteriorate the morphology of the anode, and cause rapid capacity fading. Moreover, ether electrolytes are highly flammable and trigger safety issues. As an alternative, carbonate ester electrolytes are promising choices to substitute ether electrolytes in LSBs. Organic carbonate electrolytes used in LSBs result in irreversible reactions with long-chain polysulfide anions that cause the cell to shut down. Therefore, carbonate ester electrolytes compatible sulfur cathodes design needs special attention. Sulfurized polyacrylonitrile (SPAN) and short-chain sulfur cathodes are compatible with organic carbonate electrolytes. However, the sulfur contents in these cathodes are mostly below 50 wt% which hamper the practical application of the LSBs. Here, we designed an organosulfur cathode with a high chemical bonded sulfur content of ~58 wt% in the cathode composite. The prepared organosulfur cathode showed excellent compatibility with carbonate ester electrolytes. The organosulfur cathode exhibits a high initial discharge capacity of 1301 mAh g-1 and long cycle stability for 400 cycles with nearly 99.99% coulombic efficiency.
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Sanglay, Giancarlo Dominador D., Jayson S. Garcia, Mecaelah S. Palaganas, Maurice Sorolla, Sean See, Lawrence A. Limjuco et Joey D. Ocon. « Borate-Based Compounds as Mixed Polyanion Cathode Materials for Advanced Batteries ». Molecules 27, no 22 (19 novembre 2022) : 8047. http://dx.doi.org/10.3390/molecules27228047.
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Rational design of new and cost-effective advanced batteries for the intended scale of application is concurrent with cathode materials development. Foundational knowledge of cathode materials’ processing–structure–properties–performance relationship is integral. In this review, we provide an overview of borate-based compounds as possible mixed polyanion cathode materials in organic electrolyte metal-ion batteries. A recapitulation of lithium-ion battery (LIB) cathode materials development provides that rationale. The combined method of data mining and high-throughput ab initio computing was briefly discussed to derive how carbonate-based compounds in sidorenkite structure were suggested. Borate-based compounds, albeit just close to stability (viz., <30 meV at−1), offer tunability and versatility and hence, potential effectivity as polyanion cathodes due to (1) diverse structures which can host alkali metal intercalation; (2) the low weight of borate relative to mature polyanion families which can translate to higher theoretical capacity; and a (3) rich chemistry which can alter the inductive effect on earth-abundant transition metals (e.g., Ni and Fe), potentially improving the open-circuit voltage (OCV) of the cell. This review paper provides a reference on the structures, properties, and synthesis routes of known borate-based compounds [viz., borophosphate (BPO), borosilicate (BSiO), and borosulfate (BSO)], as these borate-based compounds are untapped despite their potential for mixed polyanion cathode materials for advanced batteries.
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Li, Ming Yu, Kun Kun Wang, You Wu Su, Lin Song, Gang Cao et Gang Ren. « Study on Photo-Electro-Chemical Catalytic Degradation of Reactive Brilliant Red X-3B ». Advanced Materials Research 213 (février 2011) : 580–85. http://dx.doi.org/10.4028/www.scientific.net/amr.213.580.
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A new type of photo-electro-chemical catalytic reactor was designed. The cathode of the reactor was made of highly pure graphite and the anode was made of titanium dioxide. A saturated calomel electrode (SCE) was so used as the reference electrode that the electric potential of the cathode was determined. Under the condition of ultraviolet radiation and anodic bias-voltage, reactive brilliant red X-3B was degraded in the reactor synchronously by the process of photoelectrocatalysis with titanium dioxide anode and electrogenerated hydrogen peroxide through reducing dissolved oxygen with graphite cathode. With the cooperation of the cathode and the anode, impressive decolorizing efficiency of reactive red X-3B has been achieved. The results showed that, when the concentration of reactive brilliant red X-3B was 25mg••L-1 and the inert supporting electrolyte concentration was 0.005 mol•L-1 (1000mg•L-1) sodium sulfate, initial solution ph=4, and cathodic potential -Ec = 0.60 V, under UV radiation as well as constantly pumping air into the reactor, decolorizing efficiency of 79% has been achieved.
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Abduali, Baeshov, Ivanov Nikolay et Myrzabekov Begzat. « Electrochemical Behavior of Selenium as Part of Composite Electrode in Sulfuric Acid Medium ». JOURNAL OF ADVANCES IN CHEMISTRY 7, no 3 (17 décembre 2011) : 1378–84. http://dx.doi.org/10.24297/jac.v7i3.2373.
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The method of productiion of the composite selenium-graphitic electrodes based on organic polymer binder was proposed. Electrochemical behavior of the elementary selenium as content of composite electrode in sulfuric acid medium was assessed. A formation of hydrogen selenide during the cathode polarization, and formation of selenite and selenate ions was shown. An influence of potential spread velocity, acid concentration, and temperature of electrolyte were evaluated. Effective activation power for cathode process was estimated using the temperature-cathodic method.
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Zhang, Lei Lei, Jin Hua Huang, Zhao Yuan Song, Yi Dan Fu, Mo Liu et Tian Min He. « Evaluation and Optimization of Ba0.2Sr0.8Co0.9Nb0.1O3-δ-Gd0.1Ce0.9O1.95 Composite Cathodes for IT-SOFCs ». Materials Science Forum 787 (avril 2014) : 221–26. http://dx.doi.org/10.4028/www.scientific.net/msf.787.221.
Texte intégralRésumé :
Ba0.2Sr0.8Co0.9Nb0.1O3-δ(BSCN0.2)-xGd0.1Ce0.9O1.95(GDC) (x = 10, 20, 30 and 40 wt.%) composite cathodes were investigated for the potential application in the IT-SOFCs. The results of chemical compatibility measurement show that a small number of Gd and/or Ce ions may melt into the lattice of BSCN0.2 to form BSCN0.2-GDC solid solution. Thermal expansion coefficients effectively reduced by the incorporation of GDC. The electrochemical performance of BSCN0.2-xGDC composite cathodes increased with increasing x from 10 to 30 wt.%. When x = 30 wt.%, the area specific resistances were only 0.040 and 0.017 Ω cm2at 750 and 800oC, respectively. This improved electrochemical performance is attributed to the good thermal expansion match between BSCN0.2-xGDC composite cathode and GDC electrolyte, and the increased oxygen vacancy concentration. With further increasing x, the electrochemical performance of the composite cathode decreased. This result may be due to the ambipolar resistance model of porous composite cathode and the poor electrical conductivity of BSCN-40GDC. The maximum power densities of a BSCN0.2-30GDC/La0.9Sr0.1Ga0.8Mg0.2O3-δ/NiO-Sm0.2Ce0.8O1.9single-cell achieve 537 and 722 mW cm-2at 750oC and 800oC, respectively. These results indicate that the BSCN0.2-30GDC composite cathode is a promising candidate for IT-SOFC.
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Fitriana, Hana Nur, Jiye Lee, Sangmin Lee, Myounghoon Moon, Yu Rim Lee, You-Kwan Oh, Myeonghwa Park, Jin-Suk Lee, Jinju Song et Soo Youn Lee. « Surface Modification of a Graphite Felt Cathode with Amide-Coupling Enhances the Electron Uptake of Rhodobacter sphaeroides ». Applied Sciences 11, no 16 (18 août 2021) : 7585. http://dx.doi.org/10.3390/app11167585.
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Microbial electrosynthesis (MES) is a promising technology platform for the production of chemicals and fuels from CO2 and external conducting materials (i.e., electrodes). In this system, electroactive microorganisms, called electrotrophs, serve as biocatalysts for cathodic reaction. While several CO2-fixing microorganisms can reduce CO2 to a variety of organic compounds by utilizing electricity as reducing energy, direct extracellular electron uptake is indispensable to achieve highly energy-efficient reaction. In the work reported here, Rhodobacter sphaeroides, a CO2-fixing chemoautotroph and a potential electroactive bacterium, was adopted to perform a cathodic CO2 reduction reaction via MES. To promote direct electron uptake, the graphite felt cathode was modified with a combination of chitosan and carbodiimide compound. Robust biofilm formation promoted by amide functionality between R. sphaeroides and a graphite felt cathode showed significantly higher faradaic efficiency (98.0%) for coulomb to biomass and succinic acid production than those of the bare (34%) and chitosan-modified graphite cathode (77.8%), respectively. The results suggest that cathode modification using a chitosan/carbodiimide composite may facilitate electron utilization by improving direct contact between an electrode and R. sphaeroides.
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Brahmanandan, Sayoojyam, Shantikumar Nair et Dhamodaran Santhanagopalan. « High-Performance Zr-Doped P3-Type Na0.67Ni0.33Mn0.67O2 Cathode for Na-Ion Battery Applications ». Crystals 13, no 9 (1 septembre 2023) : 1339. http://dx.doi.org/10.3390/cryst13091339.
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Sodium-ion battery (SIB) technology started to bloom along with lithium-ion batteries (LIBs) as a supportive energy source to alleviate the cost of lithium sources for the development of energy storage devices and electric vehicles. Layered cathode materials are considered potential candidates to produce high-energy-density batteries. Among the layered cathode materials, P3-type cathodes are the least investigated in spite of their capacities, which are comparable to those of P2-type cathodes. P3-type cathodes show high polarization, leading to a poor cycle life, which impedes their extensive use in practical applications. In this work, we report on zirconium doping as an effective strategy to improve cycling stability and reduce voltage fading, another serious issue of layered cathode materials. It is found that an optimum composition of the P3-type cathode with Zr doping at the Mn site, leading to a composition of Na0.67Ni0.33Mn0.64Zr0.033O2, shows good electrochemical performance in terms of retention (89% after 100 cycles) when compared to Na0.67Ni0.33Mn0.60Zr0.067O2 (85% after 100 cycles) and an undoped sample (83% after 100 cycles). Also, remarkable performance is delivered by the Na0.67Ni0.33Mn0.64Zr0.033O2 sample, with a retention rate of 72% after 450 cycles. This result is also supported by an analysis of the amount of polarization for undoped and doped samples, which found that doping helps in improving the diffusion of ions, and the least polarization is obtained for the Na0.67Ni0.33Mn0.64Zr0.033O2 sample.
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Sheng, Kun, Honghua Ge, Xin Huang, Yi Zhang, Yanfang Song, Fang Ge, Yuzeng Zhao et Xinjing Meng. « Formation and Inhibition of Calcium Carbonate Crystals under Cathodic Polarization Conditions ». Crystals 10, no 4 (6 avril 2020) : 275. http://dx.doi.org/10.3390/cryst10040275.
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The formation of CaCO3 crystals on the cathode surface and the scale-inhibition performance of scale inhibitor 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) on the cathode surface were studied by methods of solution analysis, gravimetric analysis, SEM, FTIR, and XRD techniques. They were then compared with the results of the formation and suppression of CaCO3 crystals in aqueous solution. PBTCA had a good solution-scale-inhibition performance and good lattice-distortion effects on CaCO3 crystals in solution, which could change the CaCO3 from calcite to vaterite and aragonite crystals. The solution-scale-inhibition efficiency exceeded 97% when the PBTCA concentration reached 8 mg/L. Under cathodic polarization conditions, the surface-scale-inhibition efficiency of the cathode and solution-scale-inhibition efficiency near the cathode surface both exceed 97% at polarization potential of −1V. The addition of PBTCA significantly reduced the amount of CaCO3 crystals formed on the cathode surface and had good surface and solution-scale-inhibition effect. However, the lattice-distortion effect of PBTCA on CaCO3 crystals disappeared on the cathode surface, and the resulting CaCO3 contained only calcite crystals. The high-scale-inhibition effect of PBTCA under cathodic polarization was mainly due to the inhibition of the formation of calcium carbonate crystals by PBTCA, and not because of the lattice distortion of CaCO3 crystals.
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Saeki, Ryusei, et Takeshi Ohgai. « Determination of Activation Overpotential during the Nucleation of Hcp-Cobalt Nanowires Synthesized by Potentio-Static Electrochemical Reduction ». Materials 11, no 12 (22 novembre 2018) : 2355. http://dx.doi.org/10.3390/ma11122355.
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The crystal growth process and ferromagnetic properties of electrodeposited cobalt nanowires were investigated by controlling the bath temperature and cathodic overpotential. The cathodic overpotential during electrodeposition of cobalt nanowire arrays, ΔEcath, was theoretically estimated by the difference between the cathode potential, Ecath, and the equilibrium potential, Eeq, calculated by the Nernst equation. On the other hand, the activation overpotential, ΔEact, was experimentally determined by the Arrhenius plot on the growth rate of cobalt nanowire arrays, Rg, versus (vs.) reciprocal temperature, 1/T. The ferromagnetic cobalt nanowire arrays with a diameter of circa (ca.) 25 nm had the preferred crystal orientation of (100) and the aspect ratio reached up to ca. 1800. The average crystal grain size, Ds, of (100) peaks was estimated by X-ray diffraction patterns and was increased by decreasing the cathodic overpotential for cobalt electrodeposition by shifting the cathode potential in the noble direction. Axial magnetization performance was observed in the cobalt nanowire arrays. With increasing Ds, coercivity of the film increased and reached up to ca. 1.88 kOe.
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Sun, Shuo, Chen-Zi Zhao, Hong Yuan, Yang Lu, Jiang-Kui Hu, Jia-Qi Huang et Qiang Zhang. « Multiscale understanding of high-energy cathodes in solid-state batteries : from atomic scale to macroscopic scale ». Materials Futures 1, no 1 (18 janvier 2022) : 012101. http://dx.doi.org/10.1088/2752-5724/ac427c.
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Abstract In the crucial area of sustainable energy storage, solid-state batteries (SSBs) with nonflammable solid electrolytes stand out due to their potential benefits of enhanced safety, energy density, and cycle life. However, the complexity within the composite cathode determines that fabricating an ideal electrode needs to link chemistry (atomic scale), materials (microscopic/mesoscopic scale), and electrode system (macroscopic scale). Therefore, understanding solid-state composite cathodes covering multiple scales is of vital importance for the development of practical SSBs. In this review, the challenges and basic knowledge of composite cathodes from the atomic scale to the macroscopic scale in SSBs are outlined with a special focus on the interfacial structure, charge transport, and mechanical degradation. Based on these dilemmas, emerging strategies to design a high-performance composite cathode and advanced characterization techniques are summarized. Moreover, future perspectives toward composite cathodes are discussed, aiming to facilitate the develop energy-dense SSBs.
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Fu, Jie, Haifang Wang, Riya Jin, Pengxiao Liu, Ying Li, Yunyan Wang, Qingwei Wang et Zhumei Sun. « Enhanced Electrodesorption Performance via Cathode Potential Extension during Capacitive Deionization ». Applied Sciences 12, no 6 (10 mars 2022) : 2874. http://dx.doi.org/10.3390/app12062874.
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Complete desorption of contaminants from electrode materials is required for the efficient utilization and long service life of capacitive deionization (CDI) but remains a major challenge. The electrodesorption capacity of CDI in the conventional electrode configuration is limited by the narrow electrochemical stability window of water, which lowers the operating potential to approximately 1.2 V. Here, we report a graphite anode–titanium cathode electrode configuration that extends the cathode potential to −1.7 V and provides an excellent (100%) electrodesorption performance, which is maintained after five cycles. The improvement of the cathode potential depends on the redox property of the electrode. The stronger the oxidizability of the anode and reducibility of the cathode, the wider the cathode potential. The complete desorption potential of SO42− predicted by theoretical electrochemistry was the foundation for optimizing the electrode configuration. The desorption efficiency of Cl− depended on the ionic strength and was negligibly affected by circulating velocities above 112 mL min−1. This work can direct the design optimizations of CDI devices, especially for reactors undergoing chemisorption during the electrosorption process.