bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Aqueous-Based BiVO4 Precursor for Controlled and Enhanced Properties Towards Water Splitting
Authors: Cardenas-Martinez Jessica , Holm Thomas , Diaz-Real Jesus Adrian 
Published: July 2022

Electrochemical deposition of Bi is often obtained from non-aqueous solutions due to its natural instability in water-based solutions. In this work, we report an easy and highly reproducible method for Bi deposition on optical conductive supports as a precursor for BiVO4 synthesis. After obtaining BiVO4 from the Bi layers through hydrothermal reaction with a vanadyl precursor, the material is further modified via potentiodynamic polarization as previously demonstrated for TiO2-based materials [1]. Such a modification was used to prepare the BiVO4 electrodes for further Ni-based (NiOOH) electrocatalyst decorations [2]. The formed interfaces are studied using (photo)electrochemical and physicochemical methods to evaluate its activity towards oxygen evolution reaction. The results suggest, after tailored layer control, a comparable efficiency for the BiVO4 based on electrochemical deposition from aqueous solutions and methods based on organic solvents. Finally, electrochemical modification seemed to have a positive effect on the BiVO4 performance towards oxygen evolution. Thus, this work demonstrates a cheaper and simpler synthesis route for BiVO4 precursors and a simple method for activity modification without adding extra synthesis steps resulting in highly efficient BiVO4 photocatalysts.
Figure 1. (upper left) Electrochemical setup for Bi deposition. (lower left) Cyclic voltammograms for Bi deposition. (Right) Photographs of several BiVO4 synthesis stages.

Figure 1
(Digital Presentation) Highly Sensitive Detection of Cell Endogenous Hydrogen Sulfide Based on in-Situ Dynamic Reaction of Ag NPs
Authors: Zhou Haifeng 
Published: July 2022

The performance of nanoscale sensors can often provide insights into the extremely subtle differences between biomolecules. Meanwhile, several innovative signal transduction pathways of biosensing systems have attracted a lot of attention, but most of these are always driven by a single mechanism[1]. Herein, we demonstrate a biosensor for in situ quantification of active sulfide in the cell that utilizes the electrochemical solid-state phase transformation mechanism of the self-assembled silver nanoparticles[2], which is immobilized on the surface of the gold microelectrode through Raman signal molecules (4-aminothiophenol, 4-ATP). Taking the detection of cell endogenous hydrogen sulfide (H2S) as an example, Ag NPs could first slowly react with local H2S. Under the occurrence of the electrochemical oxidation reaction, a large number of silver ions (Ag+) are released to quickly react with H2S. Subsequently, the execution of the reduction reaction brings the complex complexes to the electrode surface. The electrochemical solid-phase transfer mechanism has a fast reaction rate, and the shift of the redox peak of Ag NPs and the strength of the Raman spectrum of 4-ATP can quickly and accurately quantitatively analyze the cell endogenous H2S with two channels, and the detection limit can reach nanomolar level. Going beyond conventional biosensing, the elaborate dynamic coupling of multiple mechanisms in a micro/nanoscale interface may open a new approach for future highly sensitive biosensing.

References

[1] H Zhou, G Ran, JF Masson, C Wang, Y Zhao, Q Song, Analytical Chemistry
2018, 90(5), 3374-3381
[2] H Zhou, R Yu, G Ran, S Moussa, Q Song, J Mauzeroll, JF Masson, Sensors and Actuators B: Chemical
2020, 319, 128315
(Digital Presentation) Investigation of the Hexylamine Adsorption on Platinum By Potentiostatic and Potentiodynamic Methods
Authors: Ostapenko Gennady I. , Kalashnikova Nina A. 
Published: July 2022

Adsorption is one of the electrochemical process stages often. The adsorption of polar organic molecules (surfactants) on metal electrodes is of significant interest. In particular, the surfactant adsorption affects the exchange current value and determines the metal corrosion rate. Therefore, the explanation of the adsorption mechanism is the most important problem in the investigation of the electrochemical kinetics.
The kinetics of the Fe2+ and Fe3+ oxidation-reduction reaction on a platinum electrode in 1 M HClO4 was investigated by potentiodynamic and chronoamperometric methods in the presence of hexylamine as a surfactant. The main kinetic characteristics of the reaction (exchange current density, transfer coefficient, diffusion coefficients of iron ions) have been determined.
The dependence of the exchange current density on the hexylamine concentration is analyzed. The surface coverage with a surfactant was estimated at various hexylamine concentrations. It was shown that the hexylamine adsorption on platinum is described by the Dhar-Flory-Huggins adsorption isotherm. The values of the adsorption constant and the adsorption free energy are obtained. These values are close to the corresponding values for the hexylamine adsorption on mild steel in hydrochloric acid. Consequently, the objective laws for the hexylamine adsorption depend low on the acid type and the electrode nature. This indicates the physical adsorption of the surfactant.
It is possible that adsorption occurs due to the hydrophobic interaction of the surfactant molecules with polar water molecules. Then, the displacement of surfactant molecules to the interface takes place regardless of the nature of the acid and the metal contacting with the solution. The latter assumption requires further investigations of the surfactant adsorption on various metals.
Transforming Silicon Slag into High-Capacity Anode Material for Lithium-Ion Batteries
Authors: Heitz Alexandre , Vanpeene Victor , Herkendaal Natalie , Soucy Patrick , Douillard Thierry , Roué Lionel 
Published: July 2022

Silicon is mainly produced by carbothermic reduction of silica. This process generates a by-product called silicon slag, which consists mainly of a mixture of Si, SiC and C. This silicon slag represents considerable energy and material losses. On the other hand, the production of cheaper and more environmentally friendly electrode materials is essential for Li-ion battery manufacturers.
In this study, it is demonstrated that this waste containing 65 wt% Si, 31 wt% SiC and 4 wt% C can be valorized as low-cost high-capacity LiB anode material. After 20 h of high-energy ball-milling, C is fully converted to SiC and a micrometric powder is obtained in which submicrometric SiC inclusions are embedded in a nanocrystalline/amorphous Si matrix (Fig. 1a). This material displays a specific discharge capacity ≥1100 mAh g-1 at a current density ≤ 0.9 A g-1 (Fig. 1b) and an areal capacity ≥3.5 mAh cm-2 for at least 100 cycles (Fig. 1c). Moreover, calendering has no negative impact on the electrode performance (Fig 1d). The dQ/dV curves (Fig. 1e) do not shown intense-sharp anodic peak at about 0.45V characteristic of the delithiation of the c-Li15Si4 phase, suggesting that its formation is here prevented. This may be beneficial for the electrode cycle life as the formation of c-Li15Si4 phase is well-known to accentuate the particle cracking. However, a progressive and irreversible increase of the electrode mass and thickness is observed over cycling (reaching 125% and 60% after 200 cycles, respectively) (Fig. 1f), which is mainly attributed to the accumulation of solid electrolyte interphase (SEI) products in the electrode.

Figure 1
(Digital Presentation) Long Cycle Life Li-Ion Batteries Using Solidified Gel Electrolyte Prepared Via in-Situ Crosslinking
Authors: Cluzeau Benoît , Dedryvere Remi , Dumont Erwan , Gillot Stephane , Jordy Christian , Pavlenko Ekaterina 
Published: July 2022

Solid Polymer Electrolytes (SPEs) are promising candidates for all-solid-state lithium batteries. Light, flexible and non-flammable, they could overtake many limits of classical Li-ion batteries. Moreover, polymer electrolytes allow for the use of Li metal as negative electrode without safety issues of dendrites formation. But the current state-of-the-art on SPEs generally reports low ionic conductivity at room temperature (RT), poor lithium transport properties, and large interfacial resistance. All these limitations explain the difficulties of SPEs to be used in practical applications at RT.
Gel Polymer Electrolytes (GPEs), composed of a polymer matrix swelled by a liquid electrolyte, are a first step to approach solid state electrolytes. Preliminary results confirm that GPEs exhibit high ionic conductivity and good interfacial contact. In addition, preparation via in-situ polymerization is compatible with the conventional Li-ion fabrication equipment simplifying the battery assembly process.
A GPE based on poly(ethylene glycol diacrylate) (PEGDA) as polymer matrix was synthetized using in-situ thermal cross-linking. Coupled with a non-flammable liquid phase, this GPE shows good performance in terms of ionic conductivity, electrochemical stability and safety. The mechanical properties can be tuned by changing the polymer-to-liquid weight ratio. As a proof of its suitability for Li-ion batteries, NMC and graphite electrodes with high loading were used to prepare 100 mAh pouch cells. After studying polymer distribution in the electrode, electrochemical testing revealed a very good capacity retention (>80% after 350 cycles).

Figure 1
Impedance-Based, Multi-Physical DC-Performance-Model for a PEMFC Stack
Authors: Goosmann Tobias , Raab Sebastian , Oppek Philipp , Weber Andre , Ivers-Tiffee Ellen 
Published: July 2022

Performance prediction for large-sized polymer electrolyte membrane fuel cell (PEMFC) stacks necessitates consideration of spatially deviating operating conditions on the nonlinear electrochemical behaviour. This interaction between operating conditions and electrochemistry is best described by complex CFD-models. But high computing power excludes stack and system modelling in real time applications.
We address this challenge by a multi-physical stack model, which couples (i) the non-linear electrochemistry within the cell, (ii) the fluid pressure drop along the gas channels and (iii) the thermal behaviour within the stack. The spatial resolution focusses on the most relevant directions and thus limits the computational effort. Simulation runtime is further reduced by modelling the electrochemical behaviour by a physico-chemically meaningful equivalent circuit model (ECM) [1], which relies on a data set of electrochemical impedance spectroscopy (EIS) measurements performed on incremental cells [2]. Individual impedance contributions are identified by the distribution of relaxation times (DRT). ECM model parameters are subsequently quantified by a CNLS-fitting procedure [3,4] and transferred to a nonlinear, zero-dimensional DC-performance-model. The magnitude of the modelled pressure depends on the gas flow within the channel and considers the change of gas composition, whereas the local gradients in current density cause gradients in released heat within the cell itself. This effect along the gas flow, the convection between fluids and solid parts of the stack (bipolar plates and cell) and the internal heat conduction between the solid control volumes are considered in the modelled thermal behaviour.
In this contribution a multi-physical stack model considering gradients in temperature, pressure and gas composition is presented. The interdisciplinary interactions and dependencies within the different physical domains, especially the influence of pressure and temperature on the non-linear electrochemical model, are shown. A concise validation based on measured data and conclusions for the possibilities of further applications as a system model will be discussed.
[1] D. Klotz et. al., ECS Transactions 25, pp. 1331-1340 (2009)
[2] M. Heinzmann et al., J. Power Sources 402, pp. 24-33 (2018).
[3] H. Schichlein et al., J. Appl. Electrochem. 32, pp. 875-882 (2002).
[4] S. Dierickx et al. Electrochimica Acta 355, 136764 (2020)
(Keynote) Selective Transport of Ionic Species in Membranes - Effects of Specific Interactions and Nano-Morphology
Authors: Münchinger Andreas , Kreuer Klaus Dieter 
Published: July 2022

Selective transport of specific ions is not only key to certain chemical and electrochemical applications, it also raises a number of interesting fundamental questions. For example, in a redox-flow battery, a membrane has to efficiently separate the electrochemically active ionic species (e.g. the different vanadium species present in anolyte and catholyte of a VRFB) while conducting other ionic species for mediating the electrochemical reactions. Fundamentally, selective transport is related to issues of ion uptake and ion mobility. There may be preferred uptake of certain ionic species while others may dominate ionic transport; under certain conditions, an anion exchange membrane (AEM) may even turn into a proton conductor.
This presentation provides insight into the effects membrane morphology and chemical interactions have on selective ion transport. Common thermodynamic considerations have been modified by including effects of ion solvation and the influence acid/base properties of the fixed ions have on counter-ion condensation. In addition, insights into the membrane’s nano-morphology allowed to identify sterical effects on ionic transport (ion-sieving).
With these sophistications, transport data are described in a quantitative way and guidelines are provided which may help to select or tailor membranes for particular applications requiring selective ion transport.
Modelling the Electrolyte Flow in the Tanks of Vanadium Redox Flow Batteries: A CFD Perspective
Authors: Prieto-Diaz Pablo Angel , Maurice Ange Anicet , Vera Marcos 
Published: July 2022

Redox flow batteries are a promising technology for large-scale energy storage. The flow of the electrolyte in the tanks is a relevant factor for battery optimization that has been largely overlooked to date, with departures from perfect mixing associated with an effective capacity loss of the system. The flow in the tanks is driven by the competing effects of inertia and buoyancy, the former associated with the momentum flux of the discharging jet and the latter with the density changes suffered by the electrolyte as it passes through the cell because of the slight changes in temperature and state of charge (SoC). Three different flow regimes may be found in the system, each dominated by one effect or the other, or by both when they are comparable. All these phenomena are governed by the current intensity applied (I), the volumetric flow (q) and the properties of the vanadium electrolyte.
In particular, it is seen that an accurate description of the effect of the temperature and state of charge on the density and specific heat of the electrolytes is essential to compute the buoyancy induced flow and heat transfer taking place in the tanks. A parametric sweep is presented to show the impact of these dependences on the mixing process, which calls for the need of accurate experimental measurements of the variation of the physical properties of the electrolytes with their temperature and state of charge.
Our numerical simulations show that the electrolytes are never perfectly mixed, and that the homogeneity of the species concentration is strongly dependent on the operation conditions and on the tank design, with details of the inlet and outlet ducts being particularly relevant. Results on the charging and discharging operations, heating process and the rising of the state of charge in the cell are presented and discussed.
Acknowledgments
This work has been partially funded by the Agencia Estatal de Investigación (PID2019-106740RB-I00 and RTC-2017-5955-3/AEI/10.13039/501100011033), and by Grant IND2019/AMB-17273 of the Comunidad de Madrid.

Figure 1
Fundamental Aspects of the Electron Transfer Processes in Non-Aqueous Redox Flow Batteries
Authors: Stracensky Thomas , Maurya Sandip , Mukundan Rangachary , Mukerjee Sanjeev 
Published: July 2022

Redox flow batteries (RFBs) have garnered increasing attention for energy storage applications with non-aqueous RFBs offering several advantages such as larger voltage windows and the prospect of high energy densities. To increase the efficacy of non-aqueous RFBs, much effort has gone into the design of redox moieties that are highly soluble, cheaper, and robust, with desired electrochemical properties. To evaluate the capability of these redox moieties for RFB applications, the kinetics and thermodynamics of electron transfer events need to be understood. These insights could help towards rational design of redox moieties and to predict RFB performance. Techniques such as cyclic voltammetry and rotating disk electrode are commonly used to study the fundamental parameters of electron transfer process and thermodynamic properties of the redox moieties in both the neutral and charged states.
In this work, we investigate the effects of supporting electrolytes on the thermodynamics and kinetics of the redox moieties. Vanadium (III) acetylacetonate and iron complexes are the bipolar model redox moieties used as both negative and positive electrolyte in non-aqueous RFB applications.1 While many redox moieties are stable in the neutral state, it is during cycling that degradation of the complexes typically occurs. As shown previously, the supporting electrolyte composition plays a key role in the performance and stability of the redox species in RFBs.2 We found that ion pairing between the charged redox moieties and the supporting electrolyte resulted in lower diffusion coefficients, it also has a negative impact on the kinetics of charge transfer process. We propose that the observed ion pairing can explain the stabilizing effects of supporting electrolytes on redox moieties. The magnitude of this effect can be explained by hard soft acid base theory (HSAB) which can be further used to predict the extent of ionic interactions of the charged species in the RFB electrolytes.

Acknowledgements:

Los Alamos National Laboratory is operated by Triad, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218NCA000001). Authors would like to thank Dr. Imre Gyuk and financial support from the U.S. Department of Energy’s Office of Electricity for the publication of this work is gratefully acknowledged.

Sharma, G.A. Andrade, S. Maurya, I.A. Popov, E.R. Batista, B.L. Davis, R. Mukundan, N.C. Smythe, A.M. Tondreau, P. Yang, J.C. Gordon, Iron-iminopyridine complexes as charge carriers for non-aqueous redox flow battery applications, Energy Storage Mater., 37 (2021), pp. 576-586

Wei X, Xu W, Huang J, Zhang L, Walter E, Lawrence C, Vijayakumar M, Henderson WA, Liu T, Cosimbescu L, Li B, Sprenkle V, Wang W. “Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All-Organic Redox Flow Battery” Angew Chem Int Ed Engl.
2015, 54 (30): 8684-7.
Investigating the Role of Temperature on the Performance of Vanadium Redox Flow Batteries Using a Steady Validated Unit-Cell Model
Authors: Muñoz Perales Vanesa , Berling Sabrina , Ibanez Santiago Enrique , Garcia - Quismondo Enrique , Palma Jesus , Vera Marcos 
Published: July 2022

Redox Flow Batteries (RFBs) are an evolved electrochemical energy storage technology crucial for the transition into a renewable energy future. Mainstream adoption of RFBs is subject to reduction of the capital and operation costs. In that sense, of particular importance is the optimization of the electrochemical stack, which affects the overall efficiency of the battery. Several studies have investigated the importance of thermal effects on the performance of vanadium redox flow batteries through transient non-isothermal models [1-2]. However, due to the simplified assumptions made by these authors some important temperature-dependent features are not included. Therefore, reliable and validated continuum models are also crucial to study the impact of the system temperature on all the fundamental physics in the electrochemical cells as well as to find the key aspects to optimize the stack.
In this work, we present a 2D stationary model of a vanadium redox flow battery cell with a comprehensive and updated multiphysics description. The model was validated at a constant temperature of 25 ºC by polarization, conductivity, and open circuit voltage measurements. In a second step, the temperature was also included as a key operating variable in the model. Electrolyte properties, electrochemical rate constants, and H2SO4 dissociation equilibrium were described as a function of temperature as well as the state of charge (SoC) and the total vanadium concentration. The model is currently being validated through a second experimental campaign (see Fig. 1) conducted inside a climatic chamber imitating different environmental scenarios. The model can be used to explore the relevance of each phenomenon or element in the electrochemical stack and the influence of the operating conditions on them, e.g. temperature, state of charge and volumetric flow rate. By using the proposed model, we can elucidate the best temperature strategy to increase the performance of vanadium redox flow batteries in diverse operating scenarios.
Figure 1. Open circuit voltage – SoC relation at different operating temperatures.

References

Al-Fetlawi, A.A. Shah, F.C. Walsh, Electrochimica Acta, 55, 78-89 (2009).

Tang, S. Ting, J. Bao, M. Skyllas-Kazacos, Journal of Power Sources, 203, 165-176 (2012).

Acknowledgments

This work has been partially funded by the Agencia Estatal de Investigación (PID2019-106740RB-I00 and RTC-2017-5955-3/AEI/10.13039/501100011033).

Figure 1
(Keynote, Digital Presentation) An Electrochemical Potential Perspective on Exchange Current Density and Work Function for Hydrogen Evolution Reaction (HER)
Authors: Parr Daniel , Dadallagei Kasun Saweendra Rathnatunga , Debie Sidney , Coduto Joshua Richard , Haas Christian D , Leddy Johna 
Published: July 2022

In 1972, Trasatti compiled the exchange current densities j0
and work functions 𝚽 for the hydrogen evolution reaction (HER) on 31 polycrystalline metals at pH 0. Exchange current density measures the HER rate and the work function measures the energy required to remove an electron from the surface of the metal to a point outside the metal. Trasatti showed a plot of log j0
vs 𝚽 linear for the so called d metals and for the sp metals. The slopes are statistically the same for the d and sp metals (6.44 and 6.6 excludes Hg) but the intercepts differ (-35.4 and -38).
Here, a thermodynamic specification for the slope of log j0
versus 𝚽 is suggested as 𝛂F/RT, where 𝛂 is the transfer coefficient for heterogeneous electron transfer.
Electrochemical potentials for species i in phase j have been used to derive the rates of heterogeneous electron transfer within a transition state context for Butler Volmer kinetics (Bard and Faulkner).
The standard chemical potential, activity, and ion charge for species i are 𝝁i
0,j, ai
j, and zi is the electrical potential is 𝝓j.
Extrapolation of the electrochemical potential to include 𝚽 and derive a rate expression for j0
yield:

The electrode potential and the work function group into a common term.

The slope of log j0
versus 𝚽 as 𝛂F/RT.

An explanation of how Pt with the highest energetic cost to remove an electron 𝚽 yields the highest log j0
is presented.

At 25 oC, F/RT = (0.05916 V)-1. Within the electrochemical potential model for log j0
versus 𝚽, the slopes of 6.44 and 6.6 for the d and sp metals at room temperature yield 𝛂 of 0.381 and 0.39. Across 30 metals, 𝛂 is estimated the same. The value of 0.4 is common in measurements of 𝛂 found for the potential dependent term in Butler Volmer kinetics.

References

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).
A.J. Bard and L. R. Faulkner, Electrochemical Methods, 1980, wiley and Sons, Chapter 2.

Acknowledgments

This work was supported by the National Science Foundation and the Army Research Office. The University of Iowa Obermann Center for Advanced Studies is acknowledged.