bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Stable Active Materials for Nonaqueous Redox Flow Batteries
Authors: Dumitrascu Adina , Guarr Thomas F.
Published: February 2020

The commercialization of truly practical nonaqueous redox flow batteries (RFBs) requires the development of compounds that are extremely stable in at least two oxidation states. Moreover, ideal RFB catholyte materials should possess high oxidation potentials (>4 V vs. Li/Li+), while their anolyte counterparts should possess relatively low reduction potentials. A series of promising RFB anolytes based on p-phenylene-bridged bis(pyridinium) compounds has been prepared and characterized. These compounds are highly soluble in polar organic solvents and undergo a chemically reversible net two-electron reduction. Because the para orientation allows the formation of a quinoidal neutral species upon 2e- reduction, the reduction product is expected to display good stability.

The synthesis, characterization, and electrochemical properties of several RFB catholytes based on phenothiazine-5,5-dioxide will also be described. These compounds exhibit chemically and electrochemically reversible one-electron oxidation at very high potentials (4.2-4.3 V vs. Li/Li+) in polar organic solvents. By attaching suitable ether functional groups, solubilities exceeding 2 M in propylene carbonate electrolytes can be achieved. Optical spectroscopy reveals that the radical cations produced by bulk electrolysis are extremely stable, undergoing minimal loss even after 1500 hours.
Fast-Charge Aluminum Battery Module Applied to Electric Bike
Authors: Lin Cong You , Huang Jau Chyn , Tseng Feng-Shun , Kuo Shu Wei , Chiang Chien Chih , Yang Chang Chung
Published: February 2020

The main goal of this work is to prolong the endurance and reduce charging time of electric bike (e-bike) with aluminum battery. The comparisons of aluminum battery from Industrial Technology Research Institute (ITRI) and commercial 48V1Ah lead-acid battery for e-bikes were investigated in this study. When lead-acid battery was charged at 1C, the charge capacity was 0.5Ah and the endurance performance of e-bike was 2km. As charging rate of lead-acid battery got higher to 5C, capacity decreased to 0.3Ah and the endurance performance of e-bike was 1km. From the result, it shows that the capacity of the lead-acid battery is decreased obviously with the charging rate increasing. Aluminum battery is a good candidate for e-bike with long vehicle range. At a current 100 mA/g, the capacity of 48V Al battery pack is 1Ah. When the charging rate is up to 5C, the capacity is 0.85AH (e.g., 85% capacity retention as compared to its 1C charge) and the endurance performance of e-bike achieves 3.4km. According to previous studies, Al battery shows the good performance at high C-rate application to offer the better endurance performance of electric bikes in the same charging time.

Keywords：Aluminum battery, Battery management system, Vehicle
Modification of the Electron Density in Prussian Blue Iron Sites to Improve the Charge Extraction at High Voltages in Sodium Ion Batteries
Authors: Oliver-Tolentino Miguel Angel , Bautista-Ramírez Marycruz , Encinas-Reyes Mar Bella , Ramos-Sánchez Guadalupe , González I.
Published: February 2020

An interesting material for the cathode of Na-Ion battery is the metal-organic open framework called Prussian Blue AFe[Fe(CN)]6 (A= alkali metals), in which alkali ions occupy half of the empty cubic cavities created by a cubic network of alternating high spin Fe and low spin Fe in the vertices and -C≡N- ligands on the edges. These materials exhibit interesting properties such as low cost, easiness of synthesis and good stability. During the charge process this material exhibit two redox processes, the first associated to high spin Fe (coordinated to nitrogen) and the second to low spin Fe (coordinated to carbon); however, the extracted charge is mainly obtained during the discharge process at lower potentials (lower energy). Thus, in this work, in order to enhance the energy density, the high spin Fe in Prussian blue is partially replaced by Mn2+ and Co2+, i.e. samples NaxMnFe[Fe(CN)]6 and NaxCoFe[Fe(CN)]6. All materials were synthetized by precipitation method, the XRD revealed that materials crystallized in cubic cell, whereas the IR and Raman spectroscopy suggested that high spin Fe is in oxidation state 3+ and iron low spin is found in 2+. Mössbauer spectroscopy was used to confirm the oxidation state of the samples; moreover, the characterization indicates that the electronic density of the iron center is modified by the presence of Mn or Co in the structure. The electrochemical performance indicated that the charge extracted during the discharge process is similar in NaxCoFe[Fe(CN)]6 and NaxFe[Fe(CN)6] whereas in the NaxMnFe[Fe(CN)]6 the higher amount of extracted charge occurs in the second process at higher voltage. Thus, the incorporation of a second metal in the structure of the Prussian Blue cathode is capable to modify the electronic structure of the sites and lead to the possibility to control the extraction of charge at high voltages.
The Interdependent Deposit-Steel Interaction during Underdeposit Corrosion (UDC)
Authors: Shamso Ahmed Nabil , Abdullah Aboubakr Moustafa , Laycock Nick , Ryan Mary P
Published: February 2020

Underdeposit Corrosion (UDC) is a major problem that faces the integrity of pipelines in the oil and gas industry, especially in sour environments (H2S- rich). Among the deposits, typically, present in sour environments, iron sulfides (FexSy) require particular attention due to their complex nature as well as their physical and chemical interaction with the bare steel, which affects the corrosion rate significantly. In this study, we investigate the changes in the surface morphology, chemical composition and electrochemical behavior of iron that is underneath sand and iron sulfides deposits. These changes are monitored after (i) potentiostatic growth of artificial pits (pencil electrode configuration), (ii) potentiostatic corrosion of an iron sheet, and (iii) a ZRA coupling of a steel-deposit pair. A scanning electron microscope coupled with an energy dispersive X-ray spectrometer (SEM/EDX), and Raman spectrometer are used to reveal the changes in the physical and chemical properties of the metal and deposits. Data are presented in terms of the deposit-metal interdependent physical and chemical changes as a function of the used deposit and the electrochemical tests.
(Invited) Low Temperature Thermal ALD TiNx and TaNx Films from Anhydrous N2H4
Authors: Wolf Steven , Breeden Michael , Kavrik Mahmut , Park Jun Hong , Alvarez Daniel , Holmes Russell , Spiegelman Jeff , Kummel Andrew C
Published: February 2020

Titanium nitride (TiN) has been extensively studied in semiconductor devices because of its ideal thermal, mechanical, and electrical properties, along with its ability to act as a diffusion barrier to WF6 during W metal fill. Similarly, tantalum nitride (TaN) is being utilized as a diffusion barrier on SiOCH to Cu, as Cu can readily diffuse, causing device reliability issues. Metal halide precursors are typically preferred over organometallic grown films when there is no concern about substrate etching; however, organometallic-grown films usually contain higher levels of carbon and oxygen contamination, which has been correlated with an increase in film resistivity. Plasma enhanced-ALD TiN has been shown to achieve optimal growth rates with lower contamination at temperatures below 350°C, but the film and underlying substrate can suffer from plasma-induced damage. In this study, low temperature thermal ALD TiNx from anhydrous N2H4 and TiCl4 was performed on SiO2, and the deposited films were studied using x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). TaNx films were grown utilizing N2H4 and tris(diethylamido)(tertbutylimido) tantalum(V) (TBTDET) and characterized similarly. In situ XPS was employed to demonstrate pulse saturation during ALD for TiCl4 + N2H4 à TiNx. AFM showed that 40 cycles of TiCl4 + N2H4 at 300°C produces pinhole-free, conformal films. Additionally, the effect of air exposure on TiNx films was studied; O attacked the TiNx film, evidenced by observing a 1.5 eV BE shift of the Ti 2p 3/2 peak. A comparison was made of the TiNx films grown at 300ºC and 400ºC with NH3 vs. N2H4; even at 400ºC there was approximately 2x more O and C and 50% more Cl in NH3 grown films. Furthermore, N2H4 films showed lower resistivities, attributed to lower contamination and likely better nucleation density, especially at 300oC. In situ XPS was also used to study TaNx films grown using TBTDET and N2H4. To study the nucleation on SiO2, an initial TBTDET exposure was performed; the Ta 4d peak position confirmed the nucleation and formation of Si-O-Ta bonds. After subsequent cycles, the Ta 4d peak shifts ~2eV toward lower binding energy upon forming Ta-N bonds. While the films were of extremely high purity with stoichiometry resembling Ta3N5, the N2H4 was unable to reduce the Ta oxidation state from films grown between 100oC and 300oC showing the need for some metals for the use of low oxidation state precursors or a stronger, highly energetic reducing agent. These studies with anhydrous N2H4 show the potential to form high purity barrier layers using low temperature thermal ALD as long as highly energetic reactants are used.
Near Surface Structures and the Electronic States of Polar InN
Authors: Yamashita Yoshiyuki , Yang Anli , Kobayashi Keisuke
Published: February 2020

InN has received great research attention because of the small band-gap (~ 0.7 eV) and superior electrical transport properties. As a wurtzite crystal lacks inversion symmetry along c-axis direction, In-polar and N-polar InN exhibit different properties. Therefore, investigation of near-surface structure and electronic states of polar InN films are important to fully realize their potential. Due to the element and chemical state specificity and the larger probing depth, hard X-ray photoelectron diffraction (HXPD) was used to investigate the near-surface structures of polar InN films [1].

The HXPD system consists of a monochromatic Cr Kα source (5414.7 eV), a high energy version of the VG SCIENTA R4000 10 kV analyzer with wide acceptance objective lens.The angle acceptance of the combined objective lens and the analyzer is ±35° with an angular resolution of 0.5°. The total energy resolution was 1 eV. In this study, the polar angle θ is defined to be zero for the photoemission direction normal to a sample surface. The θ-dependent sensitivity of the analyzer, was calibrated using an amorphous GeSbTe sample.

Figure 1 shows the HXPD patterns from In 3d5/2 and N 1s core levels of In-polar and N-polar InN. The patterns were different from each other and then they were compared with the simulation results using a multiple-scattering cluster model[2], which is shown in Fig.1. It was found that the near-surface structure of the In-polar InN film was close to the ideal wurtzite structure. On the other hand, on the N-polar InN film, defects-rich surface was formed. In addition, the existence of the In-polar domains was observed in the HXPD patterns.

References:

[1] A. Yang, Y. Yamashita, et al., Appl. Phys. Lett. 102, 031914 (2013).

[2] T. Matsushita, et a., J. Electron Spectrosc. Relat. Phenom. 178, 195 (2010).

Figure 1
(Keynote) Versatile Quinones for Long Cycle Life Aqueous Batteries and All-Solid-State Batteries
Authors: Yao Yan
Published: February 2020

Aqueous rechargeable batteries use water-based electrolytes and offer safety, robustness, and environmental friendliness over lithium-ion batteries that feature flammable organic electrolytes. However their adoption is plagued by the poor cycle life due to the structural and chemical instability of the anode materials. We will report several quinones (oxidized derivatives of aromatic compounds) as anodes for high-performance aqueous batteries. These quinones are shown to operate with long cycle life under various chemical and thermal environments. Another application of quinones is in all-solid-state batteries. One main challenge is the intrinsic mismatch between low anodic decomposition potential of sulfide electrolytes and high operating potentials of cathodes which leads to a volatile cathode–electrolyte interface and undesirable cell performance. We will report how we tailor quinones as a high-capacity cathode material in all-solid-state batteries that is chemically and electrochemically compatible with sulfide electrolyte.
(Keynote) Block Copolymer Electrolytes
Authors: Bouchet Renaud , Phan Trang , Gigmes Didier , Frenck Louise , Balsara Nitash P , Pavlenko Ekaterina , Lassagne Adrien , Ferrand Adele
Published: February 2020

Today the environment is a major society concern and the polluting fossil energy consumption, more and more expensive, is a drag on our economy, thereby the development of alternative transportation such as electric or hybrid vehicles, has become a key need for a sustainable long term development[1]. The increase of energy density necessary to promote this future revolution imposes to develop “new” chemistries for both the active electrode materials and electrolyte[2],[3]. However, for high scale applications a safety issue comes from the liquid electrolytes as they embedded organic solvents that can likely leak or generate flammable reactions. The use of a solid polymer electrolyte (SPE) could solve most of the safety issues encounter with liquid electrolyte. However, the development of SPE has been hampered by two hurdles i/ the inability to design a SPE that has both a high ionic conductivity and good mechanical properties3 and ii/ the motions of lithium ions carry only a small fraction of the overall ionic current which leads during battery operation to the formation of strong concentration gradient with highly noxious effects like favored dendritic growth[4] and limited energy density, especially when power increases. In this context, we are developing nanostructured multifunctional block copolymer electrolytes (BCE), B-A-B comprising a central A block based on poly(ethylene oxide) (PEO) that brings ionic conductivity and a B block that brings other functionalities like mechanical properties, electrochemical stability, increase of transport number etc. We will present our approach in improving the performances of BCEs starting from neutral BCEs like PS-POE-PS[5],[6] laden with a lithium salt to the single-ion BCEs (SIEL) comprising grafted lithium trifluoromethanesulfonylimide (TFSILi)[7] on the B block. Especially, we analyse the impact of the BCEs architecture (composition (ie proportion of PEO), chemistries of the A (linear vs comb PEO) and B (nature of the anions and of the main chain) blocks) on the physical properties such as the morphology, the thermodynamic transitions, the mechanic stability and the ion transport. At last, the impact of transport properties (binary vs single-ion) and mechanical properties on the lithium dendritic growth is also analysed thanks to X-ray micro-tomography. At last, for a complete analysis, the results obtained with several prototypes of batteries will also be presented.

[1] J. Tollefson, Nature, 456, 2008, 436-440

[2] F. Cheng, J. Liang, Z. Tao, J. Chen, Advanced Materials, 23, 2011, 1695-1715

[3] M. Armand, J-M Tarascon, Nature, 451, 2008, 652-657

[4] J-N Chazalviel, Physical Review A, 42, 1990, 7355-7367

[5] E. Beaudoin, T. N. T. Phan, M. Robinet et al., Langmuir 2013, 29, 10874−10880

[6] R. Bouchet, T. N. T. Phan, E. Beaudoin et al., Macromolecules 2014, 47, PP2659-2665

[7] R. Bouchet, A. Aboulaich, S. Maria et al. Nature Materials, 12, 2013, 452–457.
(Invited) High Energy Cell Design: Challenges and Quantitative Characterization of the Role of Lean Electrolyte
Authors: Wood Sean M. , Nagpure Shrikant C. , Dufek Eric J. , Xiao Jie , Liaw Boryann , Niu Chaojiang , Fang Chengcheng , Meng Ying Shirley , Dickerson Charles C
Published: February 2020

Rechargeable lithium metal batteries have significant possibility to increase specific energy above current state-of-the-art Li-ion batteries. Achieving this promise is a significant undertaking that requires precise optimization of a broad set of cell components including both active material loading and the use of lean electrolytes.

While necessary to achieve high specific energy, there is limited background and quantification of how the failure modes evolve in high energy cells which have lean electrolyte. As part of multiple on-going studies it has been found that not only does the use of lean electrolyte impact the overall cycle life of cells, but also that the quantity of electrolyte has a strong impact on mechanistic failure modes.

The quantitative assessment of losses and changes within the cell over cycling presents the possibility to more rationally design cells and understand the path forward for future research activities. This presentation will highlight how this refined level of analysis can distinctly link full cell performance with the advancement of fundamental R&D.
Design of Magnetoelectrocatalysts for the Hydrogen Evolution Reaction
Authors: Parr Daniel , DeBie Sidney J. , Leddy Johna
Published: February 2020

Recent evidence highlights a magnetic effect on electron transfer processes for the hydrogen evolution reaction (HER) [1]. To further evaluate these observations from Trasatti’s data, studies of various diamagnetic electrodes under magnetic modification were undertaken. Here, results for magnetically modified carbon black electrodes are presented. Electrodes are modified by drop casting a suspension of Nafion and carbon black onto a glassy carbon electrode. Electrodes are magnetically modified on inclusion of magnetized microparticles. HER is undertaken voltammetrically at these electrodes and evaluated for impacts on the HER rates under magnetic modification. Magnetically enhanced electron transfer rates has broad impacts on electron transfer theory and electrocatalyst design. Here, implications for design of magnetoelectrocatalysts are presented.

References

[1] Trasatti, S. Work Function, Electronegativity, and Electrochemical Behavior of Metals. III. Electrolytic Hydrogen Evolution in Acid Solution. Electroanalytical Chemistry and Interfacial Electrochemistry 39, 163-184 (1972).
Electroless Deposition of Pb Monolayer - Surface Selective, Surface Controlled, Self-Terminating Process
Authors: Wu Dongjun , Yang Wenli , Joi Aniruddha , Dordi Yezdi , Brankovic Stanko
Published: February 2020

The presented experimental results including insitu scanning tunnelling microscopy (STM), electrochemical quartz microbalance (ECQCM) and open circuit potential (OCP) transient as well as our modelling and data analysis demonstrate the new phenomenon of the electroless (e-less) deposition of Pb monolayer (ML) on Pt(111), Ru(0001), Au(111) and Cu(111) substrates. The e-less Pb ML morphology and properties resemble its underpotentially deposited counterpart. The e-less Pb ML deposition, in its nature, represents the surface selective, surface, controlled self-terminating process, Figure 1. These attributes are consequence of the synergy between particular properties of the redox processes and substrates involved in the e-less Pb ML deposition. The e-less Pb ML deposition is enabling phenomenon for the two-step e-less atomic layer deposition (ALD) cycle where the e-less Pb ML serves as a reducing agent in the surface limiting redox replacement (SLRR)[1] reaction with noble metal ions, i.e. noble metal deposition. The full e-less ALD cycle results in an overall deposition of the controlled amount of noble metal which is the function of the areal density of deposited Pb ML and the stoichiometry of the SLRR reaction. The e-less ALD is highly selective to the metal substrates at which Pb forms an e-less ML providing an advantage when certain manufacturing and integration requirements are considered.

Figure 1. Insitu STM results demonstrating e-less Pb ML deposition on Au(111). (A) starting Au(111), (B) Au surface during nucleation and growth of e-less Pb ML, moment of addition of reducing agent is indicated, (C) Full e-less Pb ML formation on Au(111). All images recorded at OCP.

References

[1] S.R. Brankovic, J.X. Wang and R. R. Adzic, Surf. Sci., 2001, 474, L173 (2001)

Figure 1
Hydrogen Generation from Sodium Borohydride Solution Catalyzed By Cobalt-Boron-Manganese Coated on Ni Foam Substrate
Authors: Norkus Eugenijus , Ramaška Donatas , Balčiūnaitė Aldona , Vaičiūnienė Jūratė , Tamašauskaitė-Tamašiūnaitė Loreta
Published: February 2020

In this study the cobalt-boron-manganese (CoBMn) films were deposited on the nickel foam (Nifoam) substrate and used as catalysts for hydrogen generation from an alkaline sodium borohydride solution. Thin CoBMn films were deposited on the Ni foam using morpholine borane as a reducing agent. The morphology and composition of the prepared catalysts were examined using Field Emission Scanning Electron Microscopy and Inductively Coupled Plasma Optical Emission Spectroscopy. Catalytic activity of the CoBMn/Ni foam catalyst was determined by measuring the amount of hydrogen generated directly from aqueous alkaline solutions of sodium borohydride (NaBH4) at different solution temperatures from 40 to 70 °C and compared with that of CoB/Ni foam.

It was found that the rate of catalytic hydrolysis of NaBH4 in an alkaline solution catalyzed by the CoB/Ni foam and CoBMn/Ni foam increases exponentially with increase in reaction temperature. The activation energy was determined from the kinetic data. Significantly greater hydrogen generation rate is obtained at the CoBMn/Ni foam as compared with that at CoB/Ni foam.

Acknowledgment

This research was funded by a grant (No. M-ERA.NET-1/2016) from the Research Council of Lithuania.
Properties and Structure of Electroless Deposited Rhenium-Rich Re-Co Thin Films
Authors: Inberg Alexandra
Published: February 2020

Unique combination of rhenium (Re) mechanical and physical properties makes it very attractive material for variety of applications. Pure Re does not have a ductile-to-brittle transition temperature. Compared to other refractory metals, Re has the greatest tensile strength and excellent creep resistance over a wide range of temperatures (up to ~2000 °C). Moreover, Re does not form stable carbides. Thus, it is potentially attractive coating on different carbon materials. Re-based alloy coatings have been produced so far mainly by chemical vapor deposition (CVD) and electroplating. Electroless deposition is relatively simple and low cost method for thin metallic and metal alloy films preparation on conductive and nonconductive surfaces. The ability of electroless plating to coat the inside of holes and recesses without using external current source or vacuum technology equipment makes it an ideal coating technology for many uses. In this study, high Re content (more than 65 at.%) Re-Co coatings were prepared by electroless deposition on a functionalized SiO2 substrate and their morphology, composition, structure and properties were studied. The obtained films were characterized by HRSEM, AFM, XPS, XRD and EBSD methods. It was shown that as deposited films are amorphous with average microhardness of 620 HV that is higher than known in literature for binary Co-Re alloys. Crystalline hcp structure of Re-Co coating was detected only after annealing at 550 oC for 1 h in vacuum. Thin coatings (250-500 nm) have demonstrated good corrosion protection of copper in salt medium reducing corrosion current at list by one order of magnitude. The annealed deposits have shown improved mechanical and electrical properties. Such films exhibit ferromagnetism and could be applied in mobile magnetic components where soft-magnetic response combined with mechanical stability is required (MEMS devices).
Competition Between Electrons and OH Radicals in Plasma Electrolysis
Authors: Delgado Hernan Eugenio , Martin Daniel Cullen , Rumbach Paul , Bartels David , Go David B.
Published: February 2020

Plasma electrochemistry consists of an electrolytic cell where the cathode or the anode is replaced by a direct current (DC) plasma. Unlike conventional electrolysis, highly reactive species such as the solvated electron (e-
aq), and the hydroxyl (OH) radical dominate the surface reactions, instead of the properties of the solid electrode. Using this configuration, plasmas have been used to process chemicals, create long-lived chemical species, and synthesize nanoparticles in electrolytic cells. However, which chemical species are introduced to the electrolyte, in what amounts, and how their respective reactions compete, are lingering questions in the field. Here, a non-thermal, atmospheric argon DC plasma was used as a cathode coupled with a platinum anode and aqueous sodium perchlorate (NaClO4) or sodium chloride (NaCl) solutions as background electrolytes. Two chemical compounds, ferricyanide (Fe(CN)6
3-) or methylene blue (MB), were used as chemical indicators to study the competitive reactions driven by e-
aq and OH, and various scavengers were used to help identify plausible reaction pathways. A simple kinetic model was used to analyze and interpret the data, revealing that the Faradaic efficiency in these systems is severely limited by the ubiquitous presence of OH.
Novel Materials and System Architecture for Membrane Based Water Treatment Technology
Authors: Mubeen Syed
Published: February 2020

Surging population and climate change will push society, ever more urgently, to harvest lower quality or impaired water supplies (e.g., sea water or brackish groundwater) for drinking water. For example, desalination of sea water has become a promising technique for providing additional sources of fresh water along coastal communities. However, the widespread adoption of desalination technologies (Reverse Osmosis and Electrodialysis) is currently limited due to its energy intensive nature and/or limited membrane lifetime and performance, especially during high operation rates.

This work focuses on developing a novel, cost-effective, electrodialysis (ED) unit. Specifically, we have replaced planar electrodes in traditional electrodialysis units with 3-D electrodes. We hypothesize that the 3-D electrode bed configuration provides large surface area per unit volume, thereby allowing high currents to be drawn at current densities short of the diffusion-limited regime. Further, iR losses due to mass transfer limitation will be minimal.
Electrocoagulation (EC) for the Removal of Silica from Mining ARD Water Treatment
Authors: Xie Zhong , Dy Eben , Qu Wei
Published: February 2020

During the nanofiltration (NF) and reverse osmosis (RO) process, ions in the reject stream becomes increasingly concentrated. NF/RO concentrates from the treatment of mining acid rock drainage (ARD) water contain high levels various impurities—depending on the geochemistry of the waste rock and the treatment processes applied. Presence of cross-linked fine colloidal particles, especially silica, at certain levels in NF/RO concentrate streams can cause membrane fouling creating significant operational and water management challenges.

Electrocoagulation (EC) is a mature technology for many types of industrial waste water treatments. The technology can remove metal ions, colloidal suspensions, fine particles, and soluble inorganic pollutants from aqueous solution by introducing highly charged polymeric metal hydroxide species. In this paper, EC is explored as a treatment option for concentrated ARD water with focus in silica removal. Fe metal plates were employed as sacrificial electrodes. The experiments systematically investigate the influence of pH, dissolved oxygen (DO), current density (CD), and duration on the formation of green rusts (GRs) and silica removal. Batch tests have proved the concept that EC is a viable approach for silica removal from 80% RO reject water. Silica can be reduced from ~14 ppm down to ~3.0 ppm under 25mA/cm2 current density for 60 minute or 12.5 mA/cm2 for 120mins. Such level of silica removal can alleviate membrane fouling during subsequent NF/RO treatment. The DO level in solution has an important influence on pH and water chemistry, governs ferrous or ferric or ferrous/ferric mixed GR generation, and impacts the removal of silica in RO rejects from ARD water. EC with ferrous green rust formation under lowest DO level is best for silica removal.
Electrosynthesis of Hypochlorous Acid in a Filter-Press-Type Reactor Equipped with Ir-Sn-Sb Oxide Anode
Authors: Murrieta Maria Fernanda , Nava José Luis
Published: February 2020

A wide range of advanced oxidation technologies have been used for water treatment, especially those contaminated by organic pollutants. Electro-Fenton-based process have been used to remove these pollutants due to the production of hydroxyl radicals (•OH). A new electrochemical Fenton-type process between electrogenerated hypochlorous acid and Fe2+ have been reported to produce hydroxyl radicals [1]. Recent study has shown the capacity of this Fenton-like process to remove a textile dye [2]. In this context, this research deals with the characterization of the electrosynthesis of hypochlorous acid from the oxidation of Cl- to be use in the future in a Fenton-like process. Microelectrolysis studies were performed to determine the anode potential range (1.6 < E < 1.9 V vs SHE) to avoid side reactions like oxygen evolution reaction, using 0.05 dm3 solution with 25 mM Na2SO4 + 35 mM NaCl at pH 3. The characterization of the electrosynthesis of active chlorine (mixture of hypochlorous acid, chlorine, and hypochlorite) was carried out in an undivided cell equipped with Ir-Sn-Sb oxide anode and stainless-steel cathode. The production of active chlorine by bulk electrolysis was formed at three anodic potentials (1.6, 1.7 and 1.9 V vs SHE) using 6 dm3 of electrolyte in recycle batch mode of operation at volumetric flow rate of 3.2 dm3 min-1 obtaining a chlorine concentration of 0.32 mM HClO, as shown in Figure 1. The influence of current density and volumetric flow rate on the conversion of active chlorine was carried out at 5 ≤ j ≤ 20 mA cm-2 and 0.8 ≤ Q ≤ 3.2 dm3 min-1, respectively. The best electrolysis was obtained at 15 mA cm-2 and 3.2 dm3 min-1, giving values of 20 % of current efficiency with energy consumption of 4 KW h m-3 for a production of 1.9 mM HClO. To elucidate if the active chlorine was reduced at the cathode, electrolysis trials were performed using the same electrolyser, which included a cationic membrane between electrodes.

References.

[1] K. Kishimoto, E. Sugimura, Water Sci. and Technol. 62 (210) 2321.

[2] Z.G. Aguilar, E. Brillas, M. Salazar, J.L. Nava, I. Sirés, Appl. Catal. B: Environ. 206 (2017) 44.

Figure 1
Stabilized Capacitive Deionization Via Voltage-Based Modification
Authors: Gao X. , Omosebi A. , Landon J. , Liu K.
Published: February 2020

Fresh water scarcity is a major threat to sustaining human activities. As noted, approximately 1.1 billion people worldwide lack access to potable water, and a total of 2.7 billion people find water scarce for at least one month of the year.1 Therefore, efficient, cost-effective, and environmentally friendly desalination technologies need to be developed to secure water accessibility. Capacitive deionization (CDI) is an electrochemical water treatment technology possessing low-pressure operation, minimized maintenance costs, environmental friendliness, and possibly higher energy efficiency than contemporary desalination technologies.2

In literature, diminished salt separation of a CDI unit is often reported during repetitive charging and discharging cycles, along with inversion behavior, i.e., desorption peaks at the beginning of charging (or adsorption) steps, which is primarily accounted for by electrochemical oxidation at the carbon anode (or the positive electrode).3 Such concern recently provoked several studies focusing on how to retain salt separation while mitigating anode oxidation. Successful methods can be summarized as follows: reduction of the charging voltage,4 use of ion-exchange materials,5 use of alternating polarization,6 operation under inverted CDI (i-CDI) mode,7 and modification of the carbon surface.8 These efforts have facilitated the development of CDI technology so as to alleviate the threat of water crisis.

In this meeting, we present the use of advanced voltage-based modification to stabilize the capacitive deionization process using predominantly microporous carbon electrodes. The mechanism of the modification on performance improvement will be explained through potential distribution measurements and the modified Donnan (mD) model.

1. https://www.worldwildlife.org/threats/water-scarcity. (Last access: Nov-09-2017)

2. Suss, M. E.; Porada, S.; Sun, X.; Biesheuvel, P. M.; Yoon, J.; Presser, V., Energy Environ. Sci.
2015, 8, 2296-2319

3. Gao, X.; Omosebi, A.; Landon, J.; Liu, K., J. Electrochem. Soc.
2014, 161, E159-E166.

4. Cohen, I.; Avraham, E.; Bouhadana, Y.; Soffer, A.; Aurbach, D., Electrochim. Acta
2013, 106, 91-100.

5. Omosebi, A.; Gao, X.; Landon, J.; Liu, K., ACS Appl. Mater. Interf.
2014, 6, 12640-12649.

6. Gao, X.; Omosebi, A.; Holubowitch, N.; Landon, J.; Liu, K., Electrochim. Acta
2017, 233, 249-255.

7. Gao, X.; Omosebi, A.; Landon, J.; Liu, K., Energy Environ. Sci.
2015, 8, 897-909.

8. Krüner, B.; Srimuk, P.; Fleischmann, S.; Zeiger, M.; Schreiber, A.; Aslan, M.; Quade, A.; Presser, V., Carbon
2017, 117, 46-54
Effect of the Oxygenated Diamond Surface on the Electrochemical Oxidation of DBT and 4,6-DMDBT
Authors: Ornelas-Dávila Omar , Lacalle-Bergeron Leticia , Dávila-Jiménez M. M. , Beltrán-Arandes Joaquim , Roig- Navarro Antoni Frances , Sancho- Llopis Juan Vicente
Published: February 2020

Boron-doped diamond (BDD) has been extensively studied by their ability to oxidize a wide range of contaminants in liquid mixtures. These electrodes have a wide potential window margin for water discharge and stability for extended periods of time (1,2). However their electrochemical activity depends on the surface composition and the degree of crystallinity. On the other hand, electrochemical oxidation techniques have received great importance in the electrochemical desulfurization of organic sulfur compounds (3,4). In the present work electrochemical oxidation of DBT and 4,6-DMDBT was studed using BDD electrode in acetonitrile-water medium (electrolyte). Also was studied the oxidation of above compounds mentioned on the preoxygenated diamond surface by VMC, Chronoamperometry and electrolysis at constant potentials. The results showed that the oxygenated species on the surface of the BDD electrode influence the electrode-analyte interactions, the kinetics and the mechanism of the oxidation process. The analysis of the extracts after the electrochemical oxidation of DBT and 4,6-DMDBT by GC / MS and HPLC-MS / MS showed that the oxidation is selective. At potentials lower than 1.75V, the main product is the formation of sulfoxide, while at potentials greater than 1.75V it is the corresponding sulfone. A mixture of sulfoxide, sulfone and other oxidation products was obtained due to the opening of the aromatic ring for potentials greater than 2.0 V and prolonged electrolysis times.

Bibliography

F. Zhi, H.B. Wang, T. Nakashima, Tata N. Rao, A. Fujishima. J. Phys. Chem. B (2003) 107, 13389-13395

P. Chaplina, D. K. Hubler, J. Farrell. Electrochimica Acta 86 (2013) 122-131

Méndez-Albores, M. A. González-Fuentes, M. M. Dávila-Jiménez, F. J. González. Journal of Electroanalytical Chemistry 751 (2015) 7–14

Lam, G. Li, C. Song, J. Chen, C. Fairbridge, R. Hui, J. Zhang. Fuel Processing Technology 98 (2012) 30-38
Influence of Electrode Distance on the Electrochemical Reduction of CO2 in Aqueous Solution
Authors: Liu Junyu , Zhou Yue , Peng Luwei , Qiao Jinli , Jung Joey
Published: February 2020

At present, the research on the electrochemical reduction of CO2 (ECR-CO2) mainly focuses on the electrode material and the catalyst. However few studies involved the reactor and reaction conditions. In this study, the commerical available nano-Sn catalyst was coated on a gas diffusion electrode to form a working electrode (Sn/GDE), the influeces of distance between the aonde and the cathode were systematically investigated in a reactor for ECR-CO2. The experiments show that for the electrode distance chnaged from 1.5 cm to 5.7 cm, both current density and Faradaic efficiency were decreased sharply from 34.6 to 10.4 mA cm-2 and 80% to 60%, respectively. However, the distance of 3.3 cm seems to be a critical point, at which the current density was no longer changed.
(Invited) Electrochemical Capacitors: Deconvolution into Capacitive and Pseudocapacitive Contributions By in-Situ Time-Resolved Optical Methods
Authors: Scherson Daniel
Published: February 2020

Despite years of research questions still remain regarding the underlying physicochemical bases of charge storage in electrochemical capacitors. Much of the controversy centers around the nature of the processes responsible for this phenomenon. Work in our laboratories has focused on dynamic aspects of charge injection into IrOx(hyd) in strongly acid aqueous media, as monitored simultaneously by chronocoulometric and time-resolved differential reflectance techniques. We have taken full advantage of the electrochromic properties of these films which makes it possible to monitor changes in the oxidation state of the Ir sites in the films and thus resolve the electrochemical response in terms of its purely capacitive and pseudocapacitive components.

Shown in the figure below are plots of ΔR/R vs time (left ordinate) and the integrated charge, Q, based on the integration of the current (right ordinate), following potential steps between (Eini → Efin) (left panels) and (Efin → Eini) (right panels) for Eini = 0.20 V and Efin = 0.67 (upper panels) and Efin = 0.60 V (lower panels). The ordinates in the two curves in each panel were adjusted so as to match the initial and final values of ΔR/R and Q. It is important to stress is that the measured time constants for both the charge and optical measurements are on the order of a few tenths of seconds, and thus much longer than the RC time constant estimated based on the electrode dimensions and conductivity of the electrolyte (see above), which would yield values on the order a fraction of a ms.

Careful inspection of these curves (as well as those involving all other values of Efin examined, revealed two important features:

the oxidation process is faster than the subsequent reduction, and, most importantly,

the rate at which total charge injection and release occurs, as judged by the electrochemical data, appears faster than that at which the Ir sites undergo redox transitions, as evidenced from the optical data. This phenomenon strongly suggests that charge can be stored in the film involving both non-redox (fast) and redox (slow) sites.

Figure 1
(Invited) Redox Mechanistic Effects on Pseudo-Capacitive Electrode Behaviour
Authors: Donne Scott W
Published: February 2020

Much ado has been made about the contributions that redox processes made to pseudo-capacitive electrode performance. Many apparently similar materials such as RuO2, MnO2 and NiOOH contribute charge through redox processes at the electrode surface; however, their performance can be quite different depending on the electrode properties and environment. The typical response for an electrochemical capacitor electrode is a box-like voltammogram; however, materials such as these have a basis of such behaviour, but may also include distinct redox peaks within the voltammogram.

Here we will examine the role that the redox mechanism for these psuedo-capacitive materials has on electrode performance, as well as investigate its impact on electrode properties, in particular crystal size. Outcomes will allow further differentiation of materials used in electrochemical capacitors.
Mn3O4-Anchored Carbon-Nanotube Based Asymmetric Supercapacitor
Authors: Kumar Ankit , Sarkar Debasish , Mukherjee Soham , Patil Satish , Shukla Ashok Kumar
Published: February 2020

A facile route to anchor pseudocapacitive materials on multi-walled Carbon Nanotubes (CNTs) to realize high-performance electrode materials for Asymmetric Supercapacitors (ASCs) is achieved. The anchoring process is achieved after direct decomposition of metal-hexacyanoferrate complexes on the CNT surface. Transmission electron microscopy (TEM) analysis reveals that the nanoparticles (NPs) are discretely attached over CNT surface without forming a uniform layer, thus making almost entire NP surface available for electrochemical reactions. Accordingly, CNT-Mn3O4 nanocomposite cathode shows significantly improved capacitive performance as compared to bare CNT electrode, validating the efficacy of designing the composite electrode. With CNT-Fe3O4 nanocomposite as paired anode, the hybrid ASC delivers a specific capacitance of 135.2 F/g at a scan rate of 10 mV/s within a potential window of 0-1.8V in the aqueous electrolyte and retains almost 100% of its initial capacitance even after 15000 cycles.
Spray Dried Cerium Oxide/Graphene/Polyaniline Composite for Supercapacitor Applications
Authors: Jeyaranjan Aadithya , Seal Sudipta
Published: February 2020

Supercapacitor materials can be broadly classified into three types: carbon based, metal oxide based and conductive polymers. Though, each of these materials has their own advantages, they also have unique drawbacks, like poor cycle life for conductive polymers, inherently low conductivity for most metal oxides and low energy density for carbon based material. In the study, a composite of these three materials is synthesized through an easily scalable process to yield a supercapacitor material with high specific capacitance, excellent rate capability and cycle life.

Micron sized cerium oxide (CeO2)/graphene/polyaniline (PANI) composites are synthesized using spray-drying and chemical reduction. First, graphene oxide/PANI composites are prepared by an in-situ polymerization technique. A hydrothermally one-step process is used synthesized CeO2 nanoparticles. These raw materials are then thoroughly mixed through ultrasonication and spray dried at 200°C. The use of PANI has two benefits. One, it acts as a binder between the inorganic CeO2 nanoparticles and GO during the spray dried process to yield micron sized spherical particles. Second, PANI also forms a uniform highly conductive layer, which boosts the electronic transmission and thereby the supercapacitance of the composite. The CeO2 improves the poor cycle life of PANI. The random stacking and agglomerating of GO and CeO2 during the spray drying process produces numerous channels which acts as pathways for the electrolytic ions. Thus the individual elements work synergistically to improve the supercapacitor performance.

The synthesized composites have been structurally characterized using XRD, FTIR and SEM. The electrochemical properties have been evaluated in standard three-electrode set-up with 3M KOH electrolyte using cyclic voltammetry, galvanostatic charge discharge curves and impedance analysis. The results from the electrochemical analysis show that the spray dried composite material show high specific capacitance, energy density and long cycle life.
Microwave Assisted Functionalization of Onion Waste-Derived Biocarbon for High-Capacitance Supercapacitors
Authors: Meléndez-González Perla Cecilia , Duarte-Urbina Omar José , Fernández-Luqueño F. , de la Torre Saenz Luis , Rodriguez-Varela F.J. , Alonso-Lemus Ivonne Liliana
Published: February 2020

Electrochemical energy storage devices such as supercapacitors are a promising alternative technology that can deliver high-power and enable high load currents. Supercapacitors are better than batteries for high and low temperature charge-discharge performance. Currently, several biomass resources are being proposed as raw material to obtain carbon electrodes for supercapacitors, mainly due to their abundant availability and low cost. In this context, the production of onion waste has increased world-wide in recent years. Onion waste includes skin, outermost layers, roots and stems. In this work, onion waste-derived biocarbons (OWB) have been obtained from the pyrolysis of skin and outermost layer at 400, 600, and 800 °C (labeled as OWB400, OWB600 and OWB800), followed by chemical activation with ZnCl2, and a novel microwave-assisted functionalization treatment with methanol. The chemical composition of the OWBs is mainly carbon (< 86 wt. %), while their structure is amorphous in nature as expected. Furthermore, high surface specific areas (SSA) up to 1611 m2g-1 have been determined, with mesoporous around 20 nm. The electrochemical characterization indicates that the specific capacitance increases at higher pyrolysis temperature. Therefore, OWB800 shows a higher electrochemical performance (capacitance of 309.32 F g-1) compared to OWB400 and OWB600, which can be ascribed to the pyrolysis temperature and the functionalization with methanol. Thus, the experimental procedure proposed here produces OWB with mesoporous structure and surface functional groups, characteristics that promote a high capacitance performance.
(Invited) Ionogels for Safer Energy Storage: The Determining Effect of the Interface
Authors: Le Bideau Jean , Asbani Bouchra , Douard Camille , Dupré Nicolas , Humbert Bernard , Marie Angélique , Brousse Thierry , Lethien Christophe
Published: February 2020

Ionogels represent a route to biphasic materials, for the use of ionic liquids (ILs) for all-solid devices. Confining ILs within host networks enhances their averaged dynamics, resulting in improved charge transport. Fragility, short relaxation times, low viscosity, and good ionic conductivity, all them appear to be related to the IL / host network interface. The presence of ILs at interface neighborhood leads to the breakdown of aggregated, structured regions that are systematically found in bulk ILs. This “destructuration”,1 as well as segregative interactions at interface,2 coupled with percolation of the bicontinuous solid/liquid interface,3 make these materials very competitive among the existing solid electrolytes. Such approach could provide (i) a route to lower locally the viscosity of ILs, and (ii) an easier pathway for diffusion of charged species. Several types of ionogels demonstrate this effect, taking into account of fully inorganic, hybrid, polymeric or organic-inorganic host networks . This “all-solid” approach can be applied to several electrochemical energy storage sources, including lithium batteries (Fig 1)2,4 and supercapacitors (Fig. 2).5 Strikingly, high performance were shown on these devices, thanks to interfacial effects of confined ILs, with sometimes heightened properties of the chosen ILs as referred to their bulk properties.2,3,6 Such solid electrolytes are particularly well suited for microdevices that we have been or are being developed (Fig. 3).5,6 Herein we will emphasize the results of a systematic study of the effect of size of confinement.

References:

[1] A. Guyomard-Lack et al., Phys. Chem. Chem. Phys., 16 (2014) 23639-23645.

[2] A. Guyomard-Lack et al., New J. Chem., 40 (2016) 4269-4276.

[3] C. V. Cerclier et al., Phys. Chem. Chem. Phys., 17 (2015) 29707—29713

[4] D. Aidoud et al., J. Power Sources, 330 (2016) 92-103

[5] M. Brachet et al., J. Mater. Chem. A, 4 (2016) 11835-11843.

[6] E. Eustache et al., Adv. Energy Mater., 5 (2015) 1500680

Figure 1