bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Self-Powered Glucose Biosensors for Fish Stress Monitoring
Authors: WU Haiyun , Shen Lihang , Ohnuki Hitoshi , Endo Hideaki 
Published: December 2020

Some biosensor systems which can make real-time monitoring of fish stress (glucose levels as the stress indicator) were developed in our laboratory. However, since these systems use a button battery as the power source, it requires regular battery replacement, which leaves some problems such as unnecessary handling stress on the fish and hindrance to continuous measurement due to interruption of measurement. In this study, we tried to develop a novel biosensor system that integrated the sensor (glucose biosensor) and power source (biofuel cell) to achieve a “Barrier-free Measurement” without battery replacement.
This sensor is powered by a biofuel cell that uses glucose as a substrate. On the other hand, the principle of the detection of glucose is based on quantifying glucose from the fluctuations in the current value obtained from the enzyme reaction. First, a self-powered glucose biosensor (Sensor 1) with a carbon rod as an electrode and neutral red as a mediator was developed, and the power generation characteristics and quantitative characteristics of the sensor were evaluated. The power generation characteristics were evaluated by the operating voltage calculated from the linear sweep voltammetry curve using an electrochemical analyzer. The quantitative characteristics were evaluated by gradually increasing the glucose concentration in the plasma sample of Nile tilapia (Oreochromis niloticus) and analyzing the relationship between the glucose concentration and the output current value of the sensor using a potentiostat. Furthermore, to improve the performance of the sensor, we manufactured another type of sensor (Sensor 2) that introducing a new carbon electrode material and carbon nanotubes (CNT). Then, the characteristics of the sensor during power generation and quantification were also evaluated.
The power generation characteristics of Sensor 1 showed an operating voltage of 295 µV cm-2 at a glucose concentration of 100 mg dL-1, which as a virtual critical point of fish stress. Besides, it was confirmed that the output current value of the sensor increased as the concentration increased in the glucose concentration range of 46.3 to 150 mg dL-1 in the plasma sample. On the other hand, Sensor 2 showed an operating voltage of 90 mV cm-2 at a glucose concentration of 100 mg dL-1, which was about 300 times the value compared with the former sensor. Furthermore, during glucose quantification, the measurable range in fish plasma samples expanded to 200 mg dL-1, which is a relatively acceptable measurement range for fish stress monitoring. Also, the S/N ratio of the Sensor 2 was also improved by 2.5 times compared with Sensor 1. These findings are suggested that our proposed sensor system, especially Sensor 2, could be applied to fish in the future after miniaturization and intensification.
New Procedure for Detecting Pesticides By Activating SERS Properties of Screen-Printed Electrodes
Authors: Fanjul Pablo , Ibáñez David , Caldevilla-Collado Paula , González-García María Begoña , Hernández-Santos David 
Published: December 2020

The lack of sensitivity traditionally associated with Raman spectroscopy has limited the development of new analytical applications. However, enhancement of Raman intensity due to the electrochemical surface-enhanced Raman scattering (EC-SERS) effect is an interesting alternative to overcome this limitation. Although different analytical methods have been used in the detection of pesticides, the complicated instrumentation and the long procedures employed lead to the development of new and easy methodologies for quick detection.
EC-SERS methodology proposed in this work for the detection of different pesticides uses metal SPEs as SERS substrates but also includes a preconcentration step as essential stage. After that, SPEs are electrochemically activated by cyclic voltammetry. Sensitivity of the methodology proposed in this work provides interesting results that allows us the detection of different pesticides. Particularly interesting are the results obtained in the detailed analysis of Raman bands of thiram and imidacloprid. Their characteristic bands allow the detection of 2.4 ppb thiram and 25 ppb imidacloprid.
Figure 1. Raman spectra of thiram, imidacloprid, malathion and chlorpyrifos obtained by EC-SERS procedure using metal SPE.

Figure 1
Poly(ethylene oxide)-Based Electrolyte for Solid-State-Lithium-Batteries with High Voltage Electrodes: Re-Evaluation of Common Beliefs
Authors: Kasnatscheew Johannes , Homann Gerrit , Stolz Lukas , Winter Martin 
Published: December 2020

Poly(ethylene oxide) (=PEO)-based solid polymer electrolytes (SPEs) are believed to be oxidatively instable, thus suitable only with “low potential” electrodes. Indeed, they reveal a sudden failure in Li metal cells when high potential positive electrodes, e.g. LiNi0.6Mn0.2Co0.2O2 (NMC622) are used. This is electrochemically detectable in an arbitrary, time – and voltage independent, “voltage noise” during charge.
A relation with the believed SPE oxidation was evaluated, for validity reasons on different electrodes including different active materials in both, potentiodynamic and galvanostatic experiments. The results indicate an exponential current increase and a potential plateau at 4.6 V vs. Li|Li+, respectively, demonstrating that the oxidation onset of the SPE is above the used working potential of NMC622, which is only charged up to 4.3 V vs. Li|Li+.
Surprisingly, a simple increase in SPE membrane thickness or a simple exchange of Li metal negative electrode with graphite electrode revealed an operation free of “voltage noise”. These experiments indicate that the Li | SPE interface, and in particular, Li dendrite formation and penetration through the SPE membrane is the significant source and counterintuitively not the literature believed SPE│NMC622 interface.(1) The concluded oxidative stability of the cheap and abundant PEO and the precisely diagnosed failure source led to modified and more systematic improvement strategies for a successful high voltage application of solid-state Li batteries, even at 40 °C.(2)

G. Homann, L. Stolz, J. Nair, I. C. Laskovic, M. Winter and J. Kasnatscheew, Sci Rep, 10, 4390 (2020).

G. Homann, L. Stolz, M. Winter and J. Kasnatscheew, iScience, [accepted] (2020).

Figure 1
Fast Determination of the Limiting Ionic Diffusion Coefficient in Lithium Metal Polymer Batteries
Authors: Devaux Didier , Leduc Hugo , Dumaz Philippe , Lecuyer Margaud , Deschamps Marc , Bouchet Renaud 
Published: December 2020

The energy conversion and its storage is a tremendous challenge for our society. Despite the great progress of the Lithium (Li)-ion technology based on flammable liquid electrolyte, their intrinsic instability is a strong safety issue for large-scale applications. The use of solid polymer electrolytes (SPEs) is an adequate solution in terms of safety and energy density thanks to their stability towards Li metal.[1] Moreover, as for conventional liquid electrolyte, the cationic transference number of poly(ethylene oxide) based SPE is typically below 0.2 which limits their power performance due to the formation of concentration gradient throughout the electrodes.[2] In such Li metal battery, the SPE acts as both separator and functionalized cathode binder ensuring ionic transport all over the battery. To increase the battery energy density a simple way is to use thicker cathode. Indeed, for a given electrode formulation, the energy density is directly linked to the active material loading.[3]
The goal of this study is to propose a quick and efficient methodology to optimize the thickness of the SPE and of the cathode based on charge transport parameters, which allows to determine the effective limiting Li+ diffusion coefficient. Revisiting a protocol by Doyle et al.[4] the battery power performance is rapidly established, at least 8 time faster than conventional cycling (charge-discharge steps) with a similar accuracy as depicted in Figure 1.[5] Then, by using an approach based on the Sand equation a limiting current density is determined. A unique mother curve of the capacity as a function of the limiting current density is obtained whatever the electrode and electrolyte thicknesses. Finally, the effective limiting diffusion coefficient is estimated which in turn allows to design the best electrode depending on electrolyte thickness.

References

[1] J.-M. Tarascon, M. Armand, Nature, 414 (2001) 359.
[2] M. Doyle, T. F. Fuller, J. Newman, Electrochim.
Acta., 39 (1994) 2073.
[3] Z. Du, Z., D. L. Wood III, C. Daniel, S. Kalnaus, J. Li, J. Appl.
Electrochem., 47 (2017) 405.
[4] M. Doyle, J. Newman, J. Reimers, J. Power Sources, 52 (1994) 211.
[5] D. Devaux, H. Leduc, P. Dumaz, M. Lecuyer, M. Deschamp, R. Bouchet, Front. Energy Res., 7 (2020) 168.

Figure 1
In Situ Synchrotron Radiation XRD and XAFS Measurements of Multilayer All-Solid-State Lithium-Ion Batteries Using Li2CoP2O7 as a Positive Electrode Material
Authors: Yamamoto Chihiro , Doi Shuichi , Nakanishi Masanori , Kobayashi Masakazu , Inagaki Masayuki , Goto Yuji , Kato Juji , Yamamoto Keita , Kato Akihiko , Kataoka Yuji 
Published: December 2020

All-solid-state lithium-ion batteries are expected as next-generation batteries due to their safety and high volumetric energy density. We reported Li2CoP2O7 (LCPO) as a positive electrode material with charge/discharge reactions over 5 V. [1–3] In this study, the structural and valence change of LCPO in multilayer all-solid-state lithium-ion batteries during charge/discharge was investigated using in situ synchrotron radiation X-ray diffraction (XRD) and X-ray Absorption Fine Structure (XAFS) measurements.
In multilayer all-solid-state lithium-ion batteries, LCPO was the positive electrode active material, Ti-based oxide was the negative electrode active material, and NASICON-type solid electrolyte was used as the solid electrolyte. Each material for the positive and negative electrodes and the solid electrolyte was made into a paste. They were laminated using a screen printing method and integrally sintered to produce multilayer all-solid-state batteries. Synchrotron radiation XRD and XAFS measurements were performed at the large synchrotron radiation facility SPring-8. In situ XRD was measured in a transmission mode using 30 keV X-rays for a multilayer all-solid-state battery. The X-ray beam had to pass through the center of the multilayer all-solid-state battery during the first charge/discharge reactions. In situ XAFS experiments were measured using a fluorescence method. XAFS scans covering the Co K edge peak were taken during the first charge/discharge reactions.
Figure 1 shows the XRD patterns of the multilayer all-solid-state battery during the first cycle in the charge/discharge process. The main diffraction peaks of LCPO are located at around 13.0°, 14.4°, and 16.7°. The diffraction peak position at 16.7° gradually shifts to the lower degree side from its uncharged state and the peak intensity decreases during the charging process. In addition, the peak shift returns to the same position at the uncharged state during the discharging process. However, that is not completely. The diffraction peak intensity at 14.4° decreases. In the XAFS measurement results, the Co K edge spectrum shifts to the higher energy side compared to the uncharged state during the charging process. The Co K edge spectrum returns to the same energy position in the uncharged state during the discharging process. These results show that the valence of Co changes from 2+ to 3+ upon charging and returns from 3+ to 2+ upon discharging. We observed how the Co of the LCPO operates while the multilayer all-solid-state battery was charging and discharging.
[1] A. Kato, The 395th Committee Of Battery Technology, (2019)
[2] M. Kobayashi, et al., The 60th Battery Symposium, 2F19, (2019)
[3] C. Yamamoto, et al., The 87th ECSJ Spring Meeting, (2020)

Figure 1
Synthesis of Refractory Metal Carbides on Carbon Fibers in Molten Salts and Their Electrochemical and Electrocatalytic Properties
Authors: Miklashov Dmitriy , Luneva Svetlana , Dolmatov Vladimir , Kuznetsov Sergey 
Published: December 2020

Method of currentless transfer in molten salts was used for synthesis of tantalum and niobium carbides coatings and crystals of molybdenum carbide on carbon fibers. Temperature of process was varied from 800 up to 900 °C, and time of process from 0.5 up to 24 hours.
Figure 1. Micrographs of carbon fiber with TaC and NbC coatings and Mo2C crystals (from left to right), obtained in molten salts melts by currentless transfer.
The splicing of fibers with each other was not observed; coatings were uniform in a cross section as well as along the fiber. Thickness of TaC and NbC coatings on carbon fiber was 50 – 250 nm. Size of crystals of Mo2C was approximately several micrometers.
Investigation of refractory metal (Ta, Nb, Mo) carbides on carbon fiber of the Carbopon-B-22 brand was carried out by impedance spectroscopy method. The values of the standard rate constants of charge transfer and capacities of the double electric layer were determined for synthesized materials in water solution with hydrogen peroxide.
Coatings and crystals of refractory metal carbides on carbon fibers can be used as catalysts and electrocatalysts. The kinetics of the electrocatalytic decomposition of hydrogen peroxide on the surface of TaC/C, NbC/C and Mo2C/C composite materials was studied. This reaction was investigated on measuring the volume of released oxygen. The initial carbon fiber of the Carbopon-B-22 brand was used as the cathode. The composite materials made of carbon fiber coated with tantalum carbide TaC (NbC) or modified by molybdenum carbide Mo2C served as the anode. The reaction order was established, the rate constants and activation energies of the hydrogen peroxide decomposition were calculated. The composition with the highest electrocatalytic activity was determined.

Figure 1
Electrochemical Reduction of ZrO2 in Molten Electrolytes
Authors: Omel'chuk Anatolii A , Gritsai Larisa V. , Bosenko Olga V , Skryptun Igor N 
Published: December 2020

The results of the electrochemical reduction of zirconium dioxide in molten electrolytes based on calcium or magnesium chloride on a liquid gallium cathode, bypassing the stage of granulation and sintering with carbohydrates, are presented. The liquid gallium cathode provides not only reliable contact with zirconium dioxide, but also favourable conditions for its reduction. The contact area of the gallium cathode with fine oxide powder is much larger than the contact area of the granulated and sintered zirconium dioxide with a solid conductor. This ensures a more uniform cathode polarization. Due to the lower specific mass, zirconium dioxide is located on the surface of gallium cathode, the convective movement of which provides more intense mass transfer at the interface of the phases and removal of recovery products from the zone of electrode reaction. Products of electrolysis under such conditions do not block neither the surface of zirconium dioxide nor the surface of the cathode. Zirconium, which is formed during the renewal, due to a larger specific mass, precipitates to the bottom of the electrolyser, and the layer of gallium protects it from interaction with the components of the molten electrolyte. In addition, due to the formation of alloys, the reduction of metal cations on liquid cathodes proceeds at more positive potentials than on solid indifferent cathodes, which reduces the specific energy consumption by electrolysis. The results of voltammetric studies confirm this conclusion.
The reduction product is fine-grained zirconium powder with an average particle size of 1—3 microns, and purity of 99.9 %. As the density of the current increases, the value of the specific surface of the powder, the specific volume of the micropore and their average radius decrease. The degree of extraction depends on the composition of the electrolyte mixture and naturally decreases when replacing cations in the melts both on the basis of calcium chloride and on the basis of magnesium chloride in the following sequence Na+ > K+ > Li+. The melt based on compounds of calcium and sodium chloride provides the best performance. The removal degree of zirconium from such melt reaches 77 %.
Ionic Liquid Membraneless Redox Flow Battery
Authors: Chaabene Nesrine , Ngo Kieu , Turmine Mireille , Vivier Vincent 
Published: December 2020

Today, ionic liquids are more and more present in many fields and more particularly in electrochemistry. Indeed, their physical and chemical properties are appealing and attractive. They are conductive solvents in which organic and inorganic salts can be dissolved depending on the nature of the anion and cation that make up the ionic liquid. However, only very few studies have reported their use in membraneless redox flow batteries (RFBs) for the storage of renewable energy 1, 2. The concept of membraneless redox-flow batteries was first reported by Ferrigno et al.3 in 2002, with the development of a millimeter-scale redox fuel cell based on the vanadium aqueous electrolyte solutions.
In this work, we have developed an ionic liquid membraneless RFB by using 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C2mimTFSI) as supporting electrolyte and Quinone (Q) and iron chloride (FeCl2) as electroactive species in a microfluidic system. Polarization curve and cyclic voltammetry were used to characterize the electrochemical properties as well as the performance of the microbattery. The proof-of-concept of the system has been shown with an open circuit potential of 0.6 V, obtained with both polarization curve and cyclic voltammetry, and with a current density ranging from 0.3 to 0.65 mA cm-2 for total flow rates of 10 to 20 µL min-1. As shown on fig. 1(b), a maximum of power of 40 µW cm-2 has been obtained. Such a technology is promising and performances can be enhanced by using 3D electrodes and optimizing the choice of the redox mediators (concentration, potential, etc.)

Navalpotro, P.; Palma, J.; Anderson, M.; Marcilla, R., A Membrane-Free Redox Flow Battery with Two Immiscible Redox Electrolytes. Angew. Chem. Int. Ed. Engl.
2017,
56 (41), 12460-12465.

Chen, R.; Bresser, D.; Saraf, M.; Gerlach, P.; Balducci, A.; Kunz, S.; Schroder, D.; Passerini, S.; Chen, J., A Comparative Review of Electrolytes for Organic-Material-Based Energy-Storage Devices Employing Solid Electrodes and Redox Fluids. ChemSusChem
2020,
13 (9), 2205-2219.

Ferrigno, R.; Stroock, A. D.; Clark, T. D.; Mayer, M.; Whitesides, G. M., Membraneless vanadium redox fuel cell using laminar flow. Journal of the American Chemical Society
2002,
124 (44), 12930-12931.

Figure 1
Quantum-Chemical Study of the Electron Transfer in CaTiF6+12CaCl2 Model System
Authors: Stuliov Yuriy V. , Kremenetsky Vyacheslav G. , Kuznetsov Sergey A. 
Published: December 2020

Today, quantum-chemical studies of the mechanism of electron transfer in molten salts based on a direct calculation of the transition state are faced with practically insurmountable computational difficulties. As our experience shows, model systems assigned to investigate the mechanism of charge transfer should include, in addition to the electroactive complex, two more of its coordination spheres. For electrolytes based on alkaline earth metal halides, this can be, for example, MTiF6+12MX2 type systems (M – Mg, Ca, Sr, Ba; X – F, Cl). The search for a transition state by standard methods will require enormous computer time and is almost unrealistic. In this paper, we proposed another approach, which is based on the analysis of frontier molecular orbitals (FMO) under various deformations of the initial structure.
The aim of this work was the using of the method of frontier molecular orbitals to study the mechanism of the electron transfer in the CaTiF6+12CaCl2 model system.
The geometry optimization of structures was performed with the Firefly program package, partially based on the source code of the GAMESS(US) program, by the density functional theory DFT/UHF method with the use of the B3LYP hybrid functional. For the F and Cl atoms quasi-relativistic basis set Stuttgart RLC ECP was used; for Ti and Ca – Stuttgart RSC 1997 ECP basis set.
In this work, we were interested in the state of the complex TiF6
2- near the cathode surface. For this reason, on one side of the model system, a flat boundary layer consisting of 12-15 chlorine and calcium ions was formed. The titanium complex is in contact with one of the calcium cations belonging to the boundary layer, because our previous studies indicate the bridge nature of electron transfer to the TiF6
2- complex. Note that adding of carbon cluster to the main system CaTiF6+12CaCl2 would require a drastic increase of the computation time. However, for qualitative conclusions, it is enough to analyze the CaTiF6+12CaCl2 system.
Based on the experimental data and the quantum-chemical analysis of FMO in the CaTiF6 + 12CaCl2 system, a mechanism for the charge transfer was proposed. The geometric structure of the transition state was shown to be not intermediate between the initial and final states of the system. As a result, it was found that the structure of this state is much less ordered than the initial structures of the boundary layer. The high efficiency of FMO method allows recommending this method as the instrument for testing hypotheses on the mechanism of electron transfer in molten salts.