bluuebunny/crossref_metadata_2025_split huggingface dataset:
Versatile Duplex Electrochemical Sensor for the Detection of CO2 and Relative Humidity Using Room Temperature Ionic Liquid
Authors: Bhide Ashlesha , Jagannath Badrinath , Graef Edward , Prasad Shalini 
Published: February 2020

In this work, we present a versatile and a robust electrochemical duplex sensor for detection of CO2 and humidity using a novel sensing material – Room temperature ionic liquid (RTIL). Rising environmental concerns have led to the development of sensors to monitor environmental conditions such as CO2, VOC's, particulate matter, temperature, and relative humidity. Requirement of sensor performance metrics such as low power, high stability, increased sensitivity has led to the investigation of RTIL as a suitable candidate for the CO2 and humidity sensing for usability in a broad range of applications from air quality monitoring in HVAC systems, weather prediction, and monitoring the environment in green houses. RTIL's are essentially solvent free electrolytes consisting of an organic cations and inorganic anions with tunable chemical and physical properties for sensing. The innovation of this study is to interface RTIL's with a metal electrode sensing platform which results in the formation of multi stack electrochemical double layer (EDL). CO2 or water molecules settle within the interstitial spaces formed between the RTIL moieties on the application of a bias potential. AC perturbation of the system causes charge redistribution in the EDL as a result of CO2 or water adsorption which is studied through an AC based technique- Electrochemical impedance spectroscopy (EIS). The frequency response of the EDL provides an insight of the impedance changes of the EDL as the environment changes around them.
We investigated the effects of ambient and elevated CO2 concentrations across a temperature range of 25- 65°C at 45% humidity on two fluorinated RTIL’s- EMIM[TF2N] and EMIM[FAP]. Performance comparison was based on the impedance response and dynamic behavior of the system based on the changes in the anionic symmetry. Both, EMIM[TF2N] and EMIM[FAP] behave similarly but EMIM[TF2N] shows a higher sensitivity to CO2 across temperatures. We also report the effect of varying humidity from 25% to 65% across temperature range of 25- 65°C on the performance of a non-fluorinated RTIL- MMIM[MeSO4]. MMIM[MeSO4] shows a larger change in impedance response with increasing humidity percentages at elevated temperatures. RTIL’s have the potential to be integrated with semiconductor technology for the sensitive detection of CO2 concentrations and humidity ranges across varying temperatures. Our work demonstrates the potential of a new strategy for achieving low power environmental sensors.
Electrodeposition of Nickel Nanostructures from Deep Eutectic Solvent / Water Mixtures
Authors: Mernissi Cherigui El Amine , Sentosun Kadir , Bals Sara , Terryn Herman , Ustarroz Jon 
Published: February 2020

Supported nickel nanoparticles (NPs) are widely used as catalysts for fuel cells and electrosynthesis, as well as for biosensors and supercapacitors. These nanomaterials can be fabricated by multiple methods. However, electrodeposition offers several advantages since it permits the growth of the NPs directly on the support of interest and allows obtaining highly electroactive nanostructures [1]. In order to produce highly electroactive nanostructures, the electrochemical processes on the nanoscale need to be understood. In this context, Deep Eutectic Solvents (DESs) have generated great enthusiasm as a new generation of non-aqueous electrolytes. They offer plenty of advantages compared to traditional aqueous electrolytes or to highly expensive ionic liquids [2]. Moreover, by adding water to the DESs, the electrolyte behavior could be remarkably different. The ability of understanding the effect (and controlling the amount) of water in DES has been proven essential to tune the chemical nature of the electrodeposited Ni nanostructures, thereby obtaining highly electroactive NPs for a wide range of applications [3-4].
The electrodeposition of nickel nanostructures on glassy carbon was investigated in 1:2 choline chloride – urea (1:2 ChCl-U) DES containing different amounts of added water. By combining electrochemical techniques, with ex-situ FE-SEM, XPS, HAADF-STEM and EDX, the electrochemical processes occurring during nickel deposition and the effect of added water were better understood. At highly negative potentials, Ni growth is halted due to water splitting and the formation of a mixed layer of Ni/Ni(OH)2(ads) [3]. Moreover, under certain conditions, the choline cations can also be (electro)chemically reduced at the electrode surface, blocking further 3D growth of the Ni NPs. Hence, a 2D crystalline Ni network can be formed in the inter-particle region, as depicted in the figure [5].
These novel nickel nanostructures can be of great interest for their electrocatalytic activity for different processes, such as the oxygen evolution reaction (OER).
References:

G-R. Li, H. Xu, X-F. Lu, J-X. Feng, Y-X. Tong, C-Y. Su. Nanoscale, 5 (2013) 4056-4069.

E.L. Smith, A.P. Abbott, K.S. Ryder. Chemical Reviews, 114 (2014) 11060–11082.

E.A. Mernissi Cherigui, K. Sentosun, P. Boockenooge, H. Vanrompay, S. Bals, H. Terryn, J. Ustarroz. The Journal of Physical Chemistry C, 121 (2017) 9337-9347.

C. Du, B. Zhao, X-B. Chen, N. Birbilis, H. Yang. Scientific Reports, 6 (2016) 29225.

E.A. Mernissi Cherigui, K. Sentosun, S. Bals, H. Terryn, J. Ustarroz. Manuscript in preparation (2017).

Figure 1
Comparison Study of Different Types of Porous Electrodes in Redox Flow Batteries
Authors: Zhou Xuelong , Wu Qixing , Lv Yunhui , Lin Liyu , Li Xiangyang 
Published: February 2020

Redox flow batteries (RFBs), which combines the attributes of fuel cells and solid-state batteries, have been recognized as one of leading technologies for storing electricity that generated from solar and wind farms due to the striking advantages, including excellent scalability, high efficiency, long lifetime as well as high safety [1]. Despite the attractive merits, the widespread deployment of this type of technology was significantly limited by technical and economical issues, such as low power density, high capacity decay rate, low energy density and high capital cost [2]. To address these issues, electrode and membrane designs are of great importance. For instance, electrode design over porous structure and surface properties is critically important for improving the power density and lowering the capital cost. With regard to the electrode design and selection, several types of carbon-fiber based electrodes, such as graphite/carbon felt, carbon paper and carbon cloth, have been employed as the electrodes of RFBs and associated pretreatment procedures have also been investigated, demonstrating decent performance in different RFB systems [3]. However, comprehensive comparison studies on these porous electrodes in RFBs are scarce. In this presentation, we will offer a comprehensive comparison between the state of art RFB electrodes (carbon felt, carbon paper, carbon cloth) in terms of macro and micro porous structure, surface properties, transport properties (hydraulic permeability, mass transfer coefficients, MacMullin number) as well as electrochemical performance. Besides, the use of some novel electrodes, such as brush structured carbon materials, in RFBs will also be disclosed in the present work. With the present comprehensive comparison study, insights on future electrode design and engineering direction will be discussed at last.
[1] A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, J.Appl.Electrochem. 41 (2011) 1137-1164.
[2] M.L. Perry, A.Z. Weber, J.Electrochem.Soc. 163 (2016) A5064-A5067.
[3] B.R. Chalamala, T. Soundappan, G.R. Fisher, M.R. Anstey, V.V. Viswanathan, M.L. Perry, Proc IEEE. 102 (2014) 976-999.
Strategies to Enhance the Performance of Polybenzimidazole Membrane Based Vanadium Redox Flow Batteries
Authors: Maurya Sandip , Park Eun Joo , Kim Yu Seung , Mukundan Rangachary 
Published: February 2020

Research on renewable energy sources such as solar and wind has dramatically dropped the cost of electricity generated from these sources. Renewables such as solar photovoltaics, wind turbines and geothermal are producing more and more electricity than ever before.1 Yet, being intermittent in nature prevents the use of such renewables as the main source for grid-scale electricity unless combined with an appropriate electrochemical energy storage (EES). Vanadium flow batteries (VFBs) are preferred choice as EES due to their elongated life cycle, quick response, ability to go for deep discharge, low cost, and independent energy-power outputs.2 However, most VFBs operate at low power densities, which increase the stack size significantly. In addition, costly Nafion® membrane is a key component regarding the high stack cost3; therefore, low power densities significantly increase the cost per kWh capacity. There are reports with improved power densities by modifying cell architecture4; still there is scope for cost reduction by replacing Nafion® completely with low-cost polybenzimidazole (PBI) membranes. PBI membrane has enticed attention thanks to its amphoteric properties, which repel vanadium ions in acid solutions.2 However, due to its high resistance, morphology and chemical structure of the membrane need to be tuned to achieve high power densities.
We report the strategies to tune the PBI membrane properties including acid treatment and thickness reduction. The objectives of these treatments are to improve the proton – sulfate ion transport while keeping permeability of vanadium ions low. Our preliminary results indicate that PBI membranes are capable of operating at higher power densities, if the transport properties and morphology are fine-tuned. Indeed, acid treated PBI membrane showed >550 mWcm-2 of peak power density, which is comparable to that of Nafion® membranes. Furthermore, the capacity decay and long term cycling performance of these PBI membranes in VFBs will be presented at the conference. To the best knowledge of the authors, this is the first instance to report the high peak power densities for PBI membranes in VFBs.

Acknowledgement

This work is supported by Laboratory Directed Research & Development, Los Alamos National Laboratory.

References:

(1) EIA - Electricity Data https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_01_a (accessed Nov 16, 2017).
(2) Maurya, S.; Shin, S.-H.; Lee, J.-Y.; Kim, Y.; Moon, S.-H. RSC Adv.
2016, 6 (7), 5198–5204.
(3) Minke, C.; Turek, T. J. Power Sources
2015, 286 (Supplement C), 247–257.
(4) Aaron, D. S.; Liu, Q.; Tang, Z.; Grim, G. M.; Papandrew, A. B.; Turhan, A.; Zawodzinski, T. A.; Mench, M. M. J. Power Sources
2012, 206, 450–453.
Advanced Bi-Additive Vanadium Electrolyte
Authors: Nie Zimin , Wang Wei , Murugesan Vijayakumar , Wei Xiaoliang , Li Bin , Liu Jun , Sprenkle Vincent 
Published: February 2020

New all vanadium with bi-additive electrolyte has 30% higher energy density and 80% wider temperature window which will be a promising energy storage option for the future grid. The solubility of the vanadium ions was improved to 2.0M, in a much wider temperature range from -5 to 50⁰C.
Our new bi-additive system containing (NH4)2HPO4 increases the V5+ intermolecular distance from ~5 angstrom to ~8 angstrom which has greatly improved the V5+ electrolyte stability and solubility. Based on the computer simulation results, two V5+ molecular will form complex with one HPO4 which will significantly increase the distance between the two V5+ molecular.
. With the new vanadium electrolyte, we demonstrated both on-line charge/discharge cycling and off-line static electrolyte stability study of at 2.0M vanadium concentration at -5 and 50⁰C. The new additive-assisted vanadium electrolyte provides a revolutionary solution to boost the VRB’s performance, stability, and cost to a whole new level.
Electrochemical Stability and Reversibility upon Cycling of Aqueous Polysulfide Electrodes Beyond the Solubility Limit
Authors: Pan Menghsuan Sam , Su Liang , Jing Linda Wei , Eiler Stephanie L. , Chiang Yet-Ming 
Published: February 2020

The low cost, high solubility, and high specific capacity of aqueous polysulfide electrodes are attractive in battery applications. Our group recently developed a redox flow battery system that used an air (oxygen) cathode and an aqueous polysulfide anode, aiming at low-cost large scale grid storage[1]. Surprisingly, for low cost electrochemically active materials such as aqueous polysulfide, the cost of auxiliary components including the supporting electrolytes and the tanks is ~2 times that of the active materials themselves. Accordingly, to further decrease the energy cost, it is imperative to increase the volumetric capacity (Ah/L) of aqueous polysulfide electrolytes.
One natural way to increase the capacity of the redox active solution is to increase the “effective” concentration of the active species, which is bounded by the solubility of the active species. However, the solubility of aqueous polysulfides in the reduced form (Na2S2) at room temperature is ~2.5M (5M total sulfur), equivalent to 67 Ah/L when utilizing capacity range between Na2S2 and Na2S4. One strategy to overcome this limitation is to leverage the redox activity of the precipitated polysulfide hydrate (Na2S2 xH2O) during the reduction reaction, which subsequently can be oxidized to the fully soluble higher-order polysulfide (Na2S4). Using this approach, we doubled the capacity to 134 Ah/L by using 10M total sulfur in the reversible cycling between Na2S2 and Na2S4. Long-term stability of this “precipitation-solution” conversion is studied using galvanostatic cycling for more than 1600 hours. In addition, XPS and SEM are utilized to measure the overall oxidation state of the precipitates and to understand the fast dissolution of the polysulfide hydrate. The overall oxidation state of the precipitates is particularly important in inferring the stability of the polysulfide species remained in the solution as the overall nominal solution composition needs to remain between Na2S2 to Na2S4 to avoid capacity fading associated with chemical decays. Furthermore, aqueous polysulfide using carbon suspension electrodes is demonstrated to alleviate large overpotential associated with insulating precipitate formation.

This work was supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

[1] Li et al., Joule
1, 306-327 (2017).
Pressure Influence on Acoustic Cavitation Phenomenonin Ionic Liquids: Electrochemical Study
Authors: Naidji Bouzid , Hallez Loic , Et Taouil Abdeslam , Rebetez Michel , Hihn Jean-Yves 
Published: February 2020

The propagation of an acoustic wave into a solution can lead to the break of liquid cohesion strengths. This results in the nucleation, growth and collapse of cavitation bubbles feed by solvent vapors and dissolved gases. This collapse may be beneficial as in the case of cleaning processing, but is clearly detrimental in some application as in the case of therapeutic treatments such as tumor ablation, or for the ultrasonic power transmission in coupling fluids. For the electrochemical processes assisted by ultrasound, its control is mandatory. Then, this phenomenon must be reduced by the application of over-pressures into the reactors [1].
To be able to determine the respective contributions of dissolved gases and of vapors into the cavitation bubble collapse, the present work will seek the effect of a limitation in dissolved gases into a sonoreactor by controlling the pressure in a low vapor pressure media: ionic liquids. Those solvents are constituted of a dissymmetric anion and cation, are liquid at room temperature, and show excellent properties for our tests such as a great conductivity. As their vapor pressure is exceptionally low, only the dissolved gases will contribute to the cavitation: as the content in dissolved gas is driven by the pressure, its reduction will result in a reduction of the cavitation activity.
In order to quantify this level, the diffusion study of electrochemical species was used as mass transfer sensor [2]. An electroactive species (Ferrocene) forming a rapid and reversible system is present in the solution at low concentration, and in presence of ultrasound, two contribution to the current in steady state conditions can be observed: one depending of the time and the other independent. Both are respectively proportional to the flow generated by the acoustic convection and to the bubble collapse at the electrode interface. The results show an important decrease of the cavitation phenomenon for argon pressure lower than 0.6 bar. A mathematical treatment of the curves allows the extrapolation up to the absolute cavitation quenching, at which the single contribution comes from convection.
[1] Parag R. Gogate, Aniruddha B. Pandit. 2005, Ultrasonic Sonochemistry , 12 , 21_27.
[2] Pollet B.G.,Hihn J-Y.,Doche M.L., Mandroyan A., Lorimer J-P., Mason T.J. 2007 , Journal of Electrochemistry Society, 154 , 131-138.

Figure 1
The Analytical Transport Network Model for Diffusive-Reactive Flow in 3-D Microstructural Networks: A Computationally Economical Model for Potential Use in Multi-Scale Modeling Efforts
Authors: Cocco Alex P. , Nakajo Arata , Grew Kyle N. , Chiu Wilson K. S. 
Published: February 2020

Electrochemical energy materials are those used in electrochemical energy conversion and storage technologies, such as batteries, fuel cells, and electrochemical capacitors. Their development is complicated by the fact that they must simultaneously satisfy a diverse set of design criteria, which in turn depend on multiple, interacting physical processes occurring across multiple length and time scales.
An energy material’s microstructure adds to its complexity: in addition to occurring across multiple length and time scales, the physical processes that determine its performance also occur within a geometrically complex, often 3-D, domain. Then, if one wishes to integrate molecular-scale knowledge (e.g., from molecular dynamics simulations, etc.) into a multi-scale design framework, it would be advantageous to have a robust, computationally inexpensive means of accounting for the geometrical complexity of a typical energy material microstructure.
In this work, we consider energy material microstructures comprised of interwoven, 3-D networks and present a heuristic, fully analytical model – the Analytical Transport Network (ATN) Model – that explicitly relates the morphology and topology of a given network’s channels to its effective transport coefficient and, in an approximate manner, its electrochemical activity.
ATN’s effective transport coefficient estimates obtained for conserved flow within a set of artificially-generated and real energy material microstructures exhibited good agreement with those obtained from electrochemical fin theory and finite element analysis, but were computed 1.5 and 6 orders of magnitude faster, respectively. In addition, the theory explicitly relates a number of morphological and topological parameters directly to the effective transport coefficient, whereby the distributions that characterize the structure are readily available for, e.g., morphological/topological optimization studies or further topological characterization by network science. In considering reacting flow, the ATN model is used to identify morphological and topological features that influence the flow consumed by reactions per the flow entering the network.
In this talk, we will present the ATN model, compare its predictions to those from existing techniques as well as to experimental measurements, and discuss how it can potentially be extended to elucidate the influence of channel morphology and topology on multi-component and transient flow.
Quantum-Continuum Simulations of High Power Density Oxide Electrodes for Pseudocapacitive Energy Storage
Authors: Keilbart Nathan D. , Okada Yasuaki , Higai Shinichi , Dabo Ismaila 
Published: February 2020

Pseudocapacitors are energy-storage devices characterized by fast and reversible redox reactions near the surface of an electrode that allows them to store large amounts of energy at fast rates [1]. Much is unknown about these materials due to the complex electrochemical reaction that occurs at the interface between the electrode and solvent. A theoretical modeling approach is developed focusing on ruthenium dioxide (RuO2), a prototypical pseudocapacitive electrode material, for analyzing the electrochemical response of an electrode under realistic conditions in order to identify the factors that control the performance. Electronic-structure methods are used in combination with a self-consistent continuum solvation model to generate a complete dataset of free energies for varying amounts of proton coverage on the surface. The dataset is used in conjunction with a grand-canonical Monte Carlo sampling technique that computes hydrogen-adsorption isotherms and the charge-voltage response of the system. Close agreement is found with experimental results of the RuO2 (110) surface under optimal surface charging conditions [2]. It is found that the intrinsic double-layer contribution represents a small fraction of the overall electrochemical response of the electrode but controls to a large extent the onset of pseudocapacitive reactions by influencing the change in the surface dipole. At variance with RuO2 (110), the double-layer capacitance of RuO2 (100) is found to vary linearly across a significant portion of the voltage range. This range of variation is also well captured by first-principles calculations of the double-layer capacitance for different coverages. The newly developed model provides a widely applicable computational method to help identify novel pseudocapacitive materials.
[1] V. Augustyn. P. Simon, and B. Dunn, Energy and Environ. Sci.
7, 1597 (2014)
[2] N. Keilbart, Y. Okada, A. Feehan, S. Higai, and I. Dabo, Phys. Rev. B
95, 115423 (2017)
Orthogonal Collocation on Finite Element Method for Lid-Driven Cavity Flow
Authors: Jang Taejin , Pathak Chintan , Subramanian Venkat R. 
Published: February 2020

Among the candidates for the Electrical Energy Storage (EES), Redox Flow Batteries (RFBs) are drawing attention towards a feasible solution. They are advantageous in flexibility and long-term stability of capacity and are therefore expected to play a critical role in the renewable energy and microgrid system. Meanwhile, the performance of the RFBs greatly depends on the motion of the electrolyte. And the problem becomes more complicated when we consider the edge effect in 2-dimensional modeling. Up to date, there is no analytical solution for the fluid dynamics of electrolyte flow in RFBs. To maximize the performance and enable optimum real-time battery management, fast and robust algorithm for the flow model and numerical simulation in multi-dimension is essential.
In this presentation, we introduce Orthogonal Collocation on Finite Element (OCFE) approach in the successive domain for the classical 2-D lid-driven cavity flow problem. The Navier-Stokes equation is mathematically reformulated as Partial Differential Equations (PDE) of stream function and vorticity. To get the vorticity boundary condition, imaginary points, which are located at the outside of the cavity boundary, are introduced. The result shows good agreements with precedential values while using minimum computational time and memory.