bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) New Lithium-Conducting Ionic Liquids and Their Polymer Electrolytes
Authors: Sanchez Jean-Yves , Eiamlamai Priew , Iojoiu Cristina , Cointeaux Laure , Martinez-Cisneros Cynthia
Published: February 2020

In PEM Fuel Cells, Ionic liquids i.e. Proton-conducting Ionic Liquids, PILs, behave as proton-conducting materials to increase PEMFC operating temperature. Based on primary, secondary or tertiary ammoniums, they are ‘self-sufficient’ i.e. they don´t require any additional acids to perform the electrochemical reactions. Thus macroporous membranes have been successfully filled by PILs. Alternatively, PILs can be too associated to proton-conducting ionomers e.g. Nafion® or high performance based ionomers beforehand turned into their ammonium form in order to avoid molecular acid release. In the first case, high mechanical strength can be obtained while the swelling of PFSA ionomers by PILs increase markedly the proton-conductivity at the anhydrous state but strongly decrease the membrane mechanical strength. While PILs are self-sufficient in electrochemical conversion (FC), usual Li-ion battery ILs based on quaternary ammonium require conversely adding a lithium salt. The well-known advantages of ILs vs liquid solvents e.g. high Fp and high sub-ambient conductivities are partly compensated by the compulsory addition of the salt, which increases the viscosity and also
the electrolyte cost. Oligoethers i.e. oligo(oxyethylene) or oligo-PEO) end-capped by 1, 2 or 3 salt moieties doesn’t match the performances of classical ionic liquids, in terms of sub-ambient conductivities but they both provide the lithium salt function and a solvating ability. This presentation will focus on new lithium-conducting oligomeric ionic liquids consisting of several oligoether chain lengths end-capped by organic perfluorinated anions. Their intrinsic ionic conductivities and those of related POE blends will be reported as well as their cationic transference numbers. Both classical ILs and oligomeric lithium-conducting ionic liquids degrading the electrolyte mechanical performances, they don´t allow thinning the polymer electrolyte films. A special attention will be paid to the reinforcement of ILs based polymer electrolytes.
Flowers-like Fe3O4/ Rgo Hybrid Nanocomposites Facile Synthesis for Rapid Detection of Riboflavin
Authors: Piraman Shakkthivel , Madhuvilakku Rajesh , Alagar Srinivasan , Mariappan Ramalakshmi
Published: February 2020

Sensors are playing a key role in deciding the long healthy life of mankind and the materials decides the economy. Hence, the present study focused on the development of a novel one-pot green biosurfactant nanoarchitecturing of flower like Fe3O4 anchored reduced graphene oxide (Fe3O4/rGO) sheets concurrently with improved physico-chemical properties for sensor applications. The flower-like Fe3O4/rGO hybrid nanocomposites are composed of Fe3O4 nanopetals with an average size of 33.2 nm connected at the center and anchored in rGO nanosheets. XPS results of Fe3O4 show the presence of mixed FeO and Fe2O3 forms corroborated with XRD analysis. The Fe3O4/rGO provides good micro-environment for convenient conjugation of biomolecules and exhibited improved riboflavin (RF) detection with 89 nM detection limit with excellent anti-interference ability, good reproducibility and stability. These excellent electrocatalytic performances are can be correlated to the increased electrode surface area, diffusion controlled electron transfer kinetic and highly stable matrix of Fe3O4/rGO with unique flower-like structure. Thus, the facile green synthesized Fe3O4/rGO nanocomposite is a promising potential electrode material for sensor applications.
(Invited) High-Resolution Scanning Electrochemical Microscopy of Biological and Artificial Nanopores
Authors: Amemiya Shigeru
Published: February 2020

In this presentation, we discuss applications of scanning electrochemical microscopy (SECM) to high-resolution imaging of biological and artificial nanopores. SECM imaging enables us to obtain unprecedented information about the kinetics, pathways, and mechanism of molecular transport through single nanopores. We characterize nanopipet electrodes as nanoscale SECM probes by transmission electron microscopy to verify their small diameters of ~30 nm. The resultant high spatial resolution of our SECM instrument is quantitatively demonstrated by imaging ion transport through the single nanopores of a thin solid silicon membrane. The nanoscale SECM approach thus established is applied to image a biological nanopore, the nuclear pore complex (NPC), in aqueous solution, which eliminates artifacts that are caused when the NPC is imaged by electron microscopy in vacuum and atomic force microscopy in air. Our SECM study of single NPCs is significant, because it will led to a greater mechanistic understanding of molecular transport through the NPC, which plays crucial roles in the gene expression regulation and gene delivery and is linked to many human diseases and therapeutics of genetic disorders.
CD62L Protein As a Potential Biomarker for Bladder Cancer
Authors: Phadke Gayatri S , Satterwhite Jennifer E , Choudhary Dharamainder , Taylor John A , Rusling James F
Published: February 2020

Early detection of bladder cancer is crucial for improved patient outcomes, as patients see a sharp decline in 5-year survival rate from 80% to < 35%, at early or late stage diagnosis of the disease respectively. Gene expression studies indicated L-selectin (CD62L) as a potential protein biomarker indicative of metastatic bladder cancer. Here, a quantitative bead-based microfluidic immunoarray for CD62L expression in human serum is described. Sandwich immunoassay is established by surface binding of primary antibody on an 8-electrode carbon array and magnetic beads decorated with multiple detection antibodies and horseradish peroxidase enzyme-labels. Electrochemical detection is conducted by injecting a hydroquinone/hydrogen peroxide activator/mediator mixture for amperometric signal detection. Our analysis of 40 patient samples shows an overall increase in CD62L concentration with progression of disease stage. A drop-off in soluble CD62L is seen for late stage, high-grade metastatic tumors. In-depth statistical analysis is conducted to examine the comparative performance of traditional immunoassay and our modified immunoarray for CD62L.
A Highly Sensitive Scanning Electrochemical Microscope Based Method for Studying Enzymatic Proton-Coupled Electron Transfer
Authors: Penhallurick Ryan , Chen Dejun , Tong YuYe
Published: February 2020

Proton-coupled electron transfer (PCET) reactions, such as those used in the electron transport chain in mitochondria for adenosine triphosphate production, photosynthesis or nucleic acid repair, are often important to proper cellular functioning and survival. Despite this, many of the mechanisms and energetics that govern PCET in proteins are not fully understood and call for further examination. One of the limitations to understanding enzymatic PCET reactions includes the limited availability of sensitive bioelectroanalytical techniques for studying this class of biological redox chemistry. In this presentation, we report a new, highly sensitive approach to probe PCET in biochemical systems through the use of a scanning electrochemical microscope (SECM) based chronoamperometric method.

The proof-of-concept and feasibility measurements were carried out on surface-immobilized cytochrome c oxidase (CcO) and coenzyme Q10 / cytochrome c reductase (bc
1). The proteins were embedded into unilamellar liposomes and then immobilized onto the surface of a gold-coated silicon wafer electrode through integration of the membrane with various gold-bonded tethers or supported lipid membranes, such as long-chain alkanethiol or thiolated-PEG-cholesterol, while in HEPES-Na buffer (at various pH). Upon contact with the surface of the lipid membrane, the platinum ultramicroelectrode SECM tip (~600 nm) was held at a potential (–0.8 V vs. Ag/AgCl) so that diffusion-controlled hydrogen evolution can take place. This reaction current is proportional to the near-tip proton concentration. Upon application of a potential via the gold-coated silicon wafer, or injection of the protein’s native electron donor, such as reduced cytochrome c, a change in the localized proton concentration was measured (shown in Figure 1). The density of immobilized protein on the surface of the electrode was analyzed by AFM in order to normalize current responses. The technique proved to be successful in detecting sub-picoampere current changes in response to proton-pumping of the transmembrane proteins towards the platinum ultramicroelectrode, which could be used for further investigations in the kinetics of other proton-coupled electron transfer proteins.

Figure 1
(Invited) Structure-Activity Relationships for CO and CO2 Electroreduction to C2 Species on Copper
Authors: Calle-Vallejo Federico
Published: February 2020

The electrochemical reduction of CO2 and CO has been extensively studied in the past few years, as it can convert such harmful oxides into useful compounds such as CH4, C2H4 and CH3CH2OH, using copper-based catalysts (1, 2). However, large overpotentials and low selectivities currently make CO2 electrolyzers commercially inviable, in spite of the low price and relatively high abundance of copper.

Therefore, it is vital to determine the structure-activity relationships that control the product selectivity as well as the reasons for the high overpotentials, so that enhanced catalysts can be rationally designed. In this talk, I will show a reaction mechanism obtained with DFT calculations for CO electroreduction to C2H4, CH3CHO, and CH3CH2OH on Cu(100) electrodes (3, 4). The mechanism proceeds via a (hydrogenated) CO dimer intermediate which can be observed experimentally (5). Based on the structure-activity relationships for Cu catalysts, I will explain the conspicuous preference of (100) terraces towards the production of C2 species such as C2H4 and CH3CH2OH. Importantly, such preference stems from the breaking of adsorption-energy scaling relations on Cu(100) (6).

Furthermore, the proposed mechanism predicts that the late stages of the electroreduction of CO to CH3CH2OH correspond to CH3CHO reduction (3, 4). Evaluating experimentally and theoretically the structure-activity relationships of CH3CHO reduction on various single-crystal Cu electrodes suggests that the selectivity of Cu catalysts towards CH3CH2OH or C2H4 can be tweaked by introducing certain undercoordinated sites (7).

References

1. M. Gattrell, N. Gupta and A. Co, Journal of Electroanalytical Chemistry, 594, 1 (2006).

2. R. Kortlever, J. Shen, K. J. P. Schouten, F. Calle-Vallejo and M. T. M. Koper, The Journal of Physical Chemistry Letters, 6, 4073 (2015).

3. F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie International Edition, 52, 7282 (2013).

4. K. J. P. Schouten, F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie International Edition, 53, 10858 (2014).

5. E. Pérez-Gallent, M. C. Figueiredo, F. Calle-Vallejo and M. T. M. Koper, Angewandte Chemie, 129, 3675 (2017).

6. H. Li, Y. Li, M. T. M. Koper and F. Calle-Vallejo, Journal of the American Chemical Society, 136, 15694 (2014).

7. I. Ledezma-Yanez, E. P. Gallent, M. T. M. Koper and F. Calle-Vallejo, Catalysis Today, 262, 90 (2016).
Photoelectrochemical Reduction of Carbon Dioxide at Copper(I) Oxide Modified with Ultra-Thin Polymer Layers
Authors: Szaniawska Ewelina , Bienkowski Krzysztof , Solarska Renata , Rutkowska Iwona Agnieszka , Rajeshwar Krishnan , Kulesza Pawel J
Published: February 2020

There has been growing recent interest in the development of electrochemical and photoelectrochemical approaches toward effective fixation (reduction) of carbon dioxide. Having in mind a fact that the linear O=C=O molecule is very stable, the CO2 electroreduction requires large overpotentials. In other words, utilization of renewable energy to convert carbon dioxide and water into fuels would require selective CO2-reduction catalysts or efficient and robust semiconductors. There is a need to design unique nano-architectures consisting of the CO2 photocatalyst/semiconductor stabilized with the outer protective layer.

Our study utilizes copper(I) oxide either stabilized with nanostructured titania or ultra-thin films of certain, conducting or redox, polymers (e.g. polyaniline, polypyrrole, PEDOT, poly(4-vinylpyridine)). While in a case of the mixed oxide semiconductor, we have explored formation the p-n heterojunction favoring increase of density of the electron population within the conduction band following deposition of TiO2 over the electrodeposited large crystals of Cu2O, in the latter case we tailor light absorption properties and affect the system’s stability. Upon illumination (from the copper(I) oxide side), charge transport to the reaction sites should be enhanced and the overall electric conductivity (at the catalytic interface) increases. Having in mind both hydrophilic and hydrophobic properties of Nafion over-coating, the outer-most ultra-thin film of Nafion, having properties of both robust (protective) layer and wetting (favoring proton mobility) medium, has been applied. Moreover, the outer-most over-layer of Nafion is expected to facilitate attraction of CO2 (dissolved in the sodium sulfate electrolyte) at the photoelectrochemically active mixed-metal-oxides interfaceSpecial attention has been paid to synthesis, characterization and optimization of the hybrid photocathode, namely the Nafion-protected mixed-oxides (Cu2O-TiO2) and polymer modified copper(I) oxide systems (deposited on fluorine-doped tin oxide covered glass, FTO) toward photoelectrochemical reduction of carbon dioxide.
(Invited) Role of Heterojunctions in Activation of CO2 Molecule
Authors: Solarska Renata , Bienkowski Krzysztof
Published: February 2020

Photo-electro-reduction of CO2 is continuously gaining a considerable interest in view of possible production of carbon-based energy carriers. Given the periodic availability of solar light, of primary importance is to orient the CO2 conversion versus formation of easily storable fuels such as, e.g. methanol or ethanol. Thus, it is important to diversify the CO2 reduction products not only by the applied potential but by careful optimisation of the working system. A default approach, consists in using p-type semiconductors as a main component of the CO2-reduction cathodes. However, the intrinsic drawback of p-type semiconductor photo-cathodes lies in low electron density in the CB and, as generally observed, the lack of catalytic properties towards CO2 reduction. Thus, in an attempt to increase the conduction band electron population, we will present herein a build-up hybrid photo-electrodes including p-type - n-type semiconductors junctions. An additional advantage of creating such p-type – n-type semiconductor heterojunction is protection of the p-type component against photocorrosion induced by largely negative potentials that offers, at the same time, the possibility to enlarge the choice of employed p-type semiconductors to relatively unstable ones. The requirements for the n-type semiconductors are fulfilled by several metal oxides such as TiO2 or SrTiO3, or KTaO3. Apart the role of heterojunction in CO2 activation, we will also point out a particular aspect of using a model system involving Au NPs of different sizes deposited on a TiO2/Ti substrate by examining the electro-reduction of carbon monoxide. This reaction appears as being the crucial, kinetically difficult, step in the electro-reduction of CO2 to alcohols and hydrocarbons. Recognition and understanding of an individual process might already give a picture of a whole system.
Theoretical Investigations of Electrochemical CO2 Reduction
Authors: Chan Karen
Published: February 2020

The electrochemical reduction of CO2 has the potential to store energy from intermittent renewable sources and to produce carbon-neutral fuels and chemicals[1]. In recent years, theoretical studies of CO2 reduction have usually applied the computational hydrogen electrode model, which allows for the determination of the energies of reaction intermediates without explicitly treating the potential and the ions in solution[2]. This thermochemical approach has been shown to correlate well with experimental onset potentials [3, 4] and applied to computational screening of new catalysts [5, 6]. However, an understanding of charge transfer barriers, kinetics, selectivity, and pH effects all require explicit consideration of solvent and charge. In this talk, I will discuss new developments in the explicit treatment of the electrochemical interface, which is based on a simple capacitor model that uses the interfacial charge to obtain barriers at constant potential [7, 8]. I will then discuss the application of such a scheme to CO2reduction: the determination of reaction pathways on transition metals field and solvation effects[9, 10], the resultant kinetics, and the implications for catalyst design.

1. Whipple, D.T. and P.J.A. Kenis, Prospects of CO2 Utilization via Direct Heterogeneous Electrochemical Reduction. The Journal of Physical Chemistry Letters, 2010. 1(24): p. 3451-3458.

2. Nørskov, J.K., et al., Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode. J. Phys. Chem. B, 2004. 108(46): p. 17886--17892.

3. Shi, C., et al., Chan, K., Yoo, J., Nørskov, J.K. Trends in electrochemical CO2 reduction activity for open and close-packed metal surfaces. Physical Chemistry Chemical Physics, 2014. 16(10): p. 4720-4727.

4. Kuhl, K.P., et al., Electrocatalytic Conversion of Carbon Dioxide to Methane and Methanol on Transition Metal Surfaces.Journal of the American Chemical Society, 2014.

5. Chan, K., et al., Molybdenum Sulfides and Selenides as Possible Electrocatalysts for CO2 Reduction. ChemCatChem, 2014. 6(7): p. 1899-1905.

6. Asadi, M., et al., Robust carbon dioxide reduction on molybdenum disulphide edges. Nature communications, 2014. 5.

7. Chan, K. and J.K. Nørskov, Electrochemical Barriers Made Simple.J. Phys. Chem. Lett., 2015: p. 2663--2668.

8. Chan, K. and J.K. Nørskov, Potential Dependence of Electrochemical Barriers from ab Initio Calculations.The Journal of Physical Chemistry Letters, 2016: p. 1686-1690.

9. Montoya, J.H., et al., Theoretical Insights into a CO Dimerization Mechanism in CO2 Electroreduction. The journal of physical chemistry letters, 2015. 6(11): p. 2032--2037.

10. Chen, L.D., Urushihara, M., Chan, K., Nørskov, J.K. Electric Field Effects in Electrochemical CO2 Reduction.ACS Catalysis, 2016.

11. Liu, X., Xiao, J., Peng, H., Hong, X., Chan, K., Nørskov, J.K. Understanding trends in CO2 reduction on transition metals. Nature Communications, 2017.
Atomistic Simulations of Lithium Ion Mobility in Battery Electrolytes
Authors: Sanders Jeffrey M , Kwak Shaun H , Krauter Caroline M , Gavartin Jacob , Pandiyan Sudharsan , Morisato Tsuguo , Browning Andrea R , Halls Mathew D
Published: February 2020

Li-ion battery electrolytes are complex solutions composed of solvents, functional additives, and lithium salts. Lithium ion mobility is a central property affecting battery performance. The chemical and physical factors impacting charge transport in complex solutions are not fully understood. Molecular dynamics (MD) simulation is a powerful technique that can provide insight into the critical details impacting ion transport in complex electrolyte solutions. Although several studies have been reported in the literature examining lithium diffusion using MD, limited computational power has restricted simulation time scales to only tens of nanoseconds. Additionally, the simulation results have been hampered due to lack of accurate force-field parameters. In this work, the enhanced predictive reliability for battery electrolytes provided by GPU-accelerated MD using the highly efficient Desmond MD engine [1], along with the quantitative OPLS3 force-field [2] is demonstrated. Using GPU-Desmond/OPLS3, hundreds of simulations can be performed in a production environment with simulation duration in excess of 1 µs. We discuss the impact that simulation duration and force-field has on the accuracy of Li-ion electrolyte simulations.

[1] K.J. Bowers, E. Chow, H. Xu, R.O. Dror, M.P. Eastwood, B.A. Gregersen, J.L. Klepeis, I. Kolossvary, M.A. Moraes, F.D. Sacerdoti, J.K.Salmon, Y. Shan and D.E. Shaw, Proceedings of ACM/IEEE Conference on Supercomputing (SC06), Tampa, Florida November 11-17, 2006.

[2] E. Harder, W. Damm, J. Maple, C. Wu, M. Reboul, J.Y. Xiang, L. Wang, D. Lupyan, M.K. Dahlgren, J.L. Knight, J.W. Kaus, D.S. Cerutti, G. Krilov, W.L. Jorgensen, R. Abel, R.A. Friesner, J. Chem. Theory Comput., 2016, 12 (1), pp 281; DOI: 10.1021/acs.jctc.5b00864
(Invited) Toward Design Principles for Anion Exchange Membranes with High Hydroxide Conductivity
Authors: Tuckerman Mark E. , Zelovich Tamar E. , Long Zhuoran E.
Published: February 2020

It is clear that in the identification and development of clean energy sources, a range of technologies will need to be leveraged. Electrochemical devices are an important part of this mix of technologies, and among these, fuel cells constitute some of the cleanest and most sustainable. However, several key hurdles to harnessing the potential of fuel cells (as well as various other electrochemical technologies) remain to be surmounted. We have mounted a Materials Genome Initiative project that aims to address these challenges by designing, synthesizing, and testing new materials for use in alkaline fuel cells and to discover a set of rules for best practices in the development of future materials for fuel cell applications. The team of investigators has chosen to focus on anion exchange membrane fuel cells, which have advantages over other types of fuel cells in not requiring precious metals and being operable with a variety of fuels at low temperature. The project will employ a cohesive strategy involving mathematical and computer modeling of specific materials components, which will, in turn, guide the synthesis of new materials, characterization and testing of these in actual fuel cells, and the determination of optimized key design principles that will govern future materials engineering for electrochemical applications. In this talk, I will outline the strategy of the proposed research and present preliminary results from work done to date.
The Impedance Analyzer: An Open-Source, Web-Based Tool for Sophisticated Interrogation of Experimental EIS Spectra
Authors: Murbach Matthew D. , Hu Victor Waiman , Schwartz Daniel T.
Published: February 2020

Electrochemical impedance spectroscopy (EIS) is a powerful technique for partitioning a system’s performance into contributions from individual physicochemical processes via their characteristic frequencies.1 Typically, analysis of experimental EIS spectra aims to extract meaningful information by fitting an equivalent circuit analog composed of ideal circuit elements representing different physicochemical phenomena within the cell. While fitting an equivalent circuit to experimental data is easily accomplished using nonlinear least squares regression, the lumped nature and lack of direct physical interpretation of the resulting parameters can limit the information content of the analysis.2

An alternative approach for extracting meaningful parameters from the data is to directly fit physics-based mathematical models of the electrochemical systems. In fact, many decades of electrochemical modeling research have laid the groundwork for the physics-based modeling of impedance in a wide variety of fields including corrosion,3 hydrodynamic systems,4
fuel cells,5
and lithium ion batteries.6However, despite the important role and wide acceptance of these physics-based models, their impact in experimental impedance analysis has been limited by their complexity – these models often contain many coupled partial differential equations representing the different physicochemical processes.

Here we present an open-source, web-based tool for the in-depth analysis of experimental EIS spectra. We show that building a large database of simulated spectra across a wide range of parameters enables deeper insight into the electrochemical system under study. As a demonstration, we present an analysis of experimental lithium ion battery data using the widely utilized pseudo 2-dimensional (P2D) battery model.

References:

1. M. E. Orazem and B. Tribollet, Electrochemical impedance spectroscopy, p. 523, Wiley, Hoboken, N.J, (2008).

2. S. Fletcher, J. Electrochem. Soc., 141, 1823–1826 (1994).

3. D. D. Macdonald, S. Real, S. I. Smedley, and M. Urquidi‐Macdonald, J. Electrochem. Soc., 135, 2410–2414 (1988).

4. D. T. Schwartz, P. Stroeve, and B. G. Higgins, J. Electrochem. Soc., 136, 1755–1764 (1989).

5. J. R. Wilson, D. T. Schwartz, and S. B. Adler, Electrochimica Acta, 51, 1389–1402 (2006).

6. M. Doyle, J. P. Meyers, and J. Newman, J. Electrochem. Soc., 147, 99–110 (2000).

Figure 1
Use of Kissa Software for Accurate Simulation of Electrochemical Problems of Any Compexity
Authors: Svir Irina , Klymenko Oleksiy , Oleinick Alexander , Amatore Christian Andre
Published: February 2020

KISSA-software (for 1D and 2D electrode geometry) developed in our group, provides a general framework to treat electrochemical problems (by providing mechanism, rate constant, diffusion coefficients etc.) of any complexity in a user-friendly environment and returns the simulations results without any intervention into numerical part from the user side [1]. The accuracy of the numerical solution is guaranteed in KISSA by employment of a non-uniform and adaptive grid. The latter is constructed on the basis of a kinetic criterion (rather than on a gradient-based one as in other programs) and provides a high dynamic resolution at the acute reaction fronts which are automatically detected and followed by the program [2-5]. The efficiency of this strategy was proved by addressing such sophisticated problems as i) simulation of reaction mechanisms leading to the emission of electrochemiluminescence (ECL) and ii) including the reactive dynamic adsorption.

In this context considered ECL systems [6,7] are representative example of systems possessing extremely sharp reaction fronts since some reaction constants are close to the diffusion limit (either cation/anion radicals annihilation reactions or luminophor/co-reactant reaction). More precisely, for the ECL co-reactant system, such as alkyl amines / transition metal(II) complexes, it was shown via simulations with KISSA that changes in ECL intensities emitted by these systems are much more dependent on the relative diffusivities of the two co-reactants than on the range of thermodynamic and kinetic rate constants that are possible to explore and vary.

Second example is the competitive reactive adsorption is also involved as an important class of problems covered by KISSA [8-10].

A couple examples of real data imported to KISSA for comparison to simulations for elucidation of mechanism and determination of the parameters are presented. References:

 KISSA-group: http://kissagroup.com/

C. Amatore, O. Klymenko, I. Svir, Electrochem. Commun., 12, 1170-1173 (2010).

C. Amatore, O. Klymenko, I. Svir, Electrochem. Commun., 12, 1165-1169 (2010).

O. V. Klymenko, I. Svir, A. I. Oleinick, C. Amatore, ChemPhysChem, 13, 845-859 (2012).

C. Amatore, O. Klymenko, I. Svir, Anal. Chem., 84, 2792-2798 (2012).

O.V. Klymenko, I. Svir, C. Amatore, ChemPhysChem, 14, 2237-2250 (2013).

I. Svir, A. Oleinick, O.V. Klymenko, C. Amatore, ChemElectroChem, 2, 811-818 (2015).

O. V. Klymenko, I. Svir, C. Amatore, J. Electroanal. Chem., 688, 320-327 (2013).

O.V. Klymenko, O. Buriez, E. Labbé, D. Zhan, S. Rondinini, Z. Tian, I. Svir, C. Amatore, ChemElectroChem, 1, 227-240 (2014).

O. Klymenko, I. Svir, C. Amatore, Mol. Phys., 112, 1273-1283 (2014).
(Invited) Visualizing Electrochemical Reactions at the Nanoscale By in-Situ TEM
Authors: Xin Huolin L. , Ge Mingyuan , Chu Yong S
Published: February 2020

Over the past five years, we have witnessed a rapid growth in liquid and gas flow holders for TEM and X-ray microscopes. These holders have enabled direct imaging of material transformations in liquid and gaseous environments with submicron-scale to atomic-scale spatial resolution. In particular, research regarding electrode materials in lithium ion batteries and nanocatalysts in heterogeneous catalysis has greatly benefited from the emergence of these capabilities. Despite their initial success in in-situ battery studies, similar class of problems in electrocatalysis has been rarely addressed using existing liquid electrochemical holders. In this talk, I will showcase the capability of direct nanoscale visualization of electrochemical formation and degradation of electrocatalysts utilizing an operando TEM liquid holder and I will also discuss existing challenges that the in-situ EM field need to address.

Acknowledgement

The research used resources of the National Synchrotron Light Source II and the Center for Functional Nanomaterials, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. The electron microscopy experiment was performed at the Center for Functional Nanomaterials. This research is also partially supported by Laboratory Directed Research and Development (LDRD15-037) program at the Brookhaven National Laboratory.
Nanoscale Electrochemistry Via Lithium Focused Ion Beam
Authors: McGehee William R. , Strelcov Evgheni , Gardner Jamie , Takeuchi Saya , Kirillov Oleg A. , Oleshko Vladimir P. , Gundlach David J. , Soles Christopher L. , Zhitenev Nikolai , McClelland Jabez J.
Published: February 2020

The increasing demand for smaller, lighter, cheaper, and more stable power sources for portable electronics, vehicles and aircrafts spurs intensive research of the lithium ion batteries. Rational battery engineering, including design of smart electrode materials, is impossible without in-depth understanding of the chemical and physical processes in galvanic cells at the microscopic, nanoscopic, and eventually, molecular levels. Reaction mechanisms, cathode expansion, formation of cracks and SEI layer, electrolyte decomposition etc., are being extensively studied with a variety of ex and in situ microscopic, spectroscopic and electrochemical techniques. However, a significant drawback of the existing methodologies is their inability to deliver Li+ ions and control their concentration at the nanoscale level. In addition, the classic electrochemical techniques imply existence of liquid-solid interfaces and inevitable formation of SEI layer. This is a significant impediment for studying lithium diffusion and associated morphological changes in cathode materials.

We report progress in developing Li+ focused ion beams (FIB) as a novel probe for exploring nanoscale electrochemistry in battery-relevant materials. This work focuses on implantation of lithium ions in crystalline silicon to benchmark this technique and builds on recent, qualitative studies of FIB implantation in Sn microspheres [Takeuchi et al. JES 163 (6), A1010-A1012]. FIB implantation opens the possibility of precise spatial control of nanoscale lithium concentration though variation of the beam positioning and current. Experiments are performed in vacuo without the presence of electrolytes or associated solid-electrolyte interface. The Li+ ion beam operates with energies ranging from 0.5 to 5 keV, currents up to 15 pA, and minimum spot size of 27 nm using a magneto-optical trap ion source (MOTIS).

WRM acknowledges support from the National Research Council Research Associateship Program. ES and JG acknowledge support under the Cooperative Research Agreement between the University of Maryland and the National Institute of Standards and Technology Center for Nanoscale Science and Technology, Award 70NANB14H209, through the University of Maryland.
(Invited) A New Class of Fluorinated Alkoxyaluminate Electrolytes for Magnesium-Ion Batteries
Authors: Herb Jake Tompkins , Nist-Lund Carl , Arnold Craig B.
Published: February 2020

One of the major challenges that has limited the success of magnesium-ion based battery chemistries is the development of suitable electrolytes that enable the reversible deposition of magnesium metal with high coulombic efficiency, high conductivity, and practical oxidative stability on non-noble metal surfaces. With few exceptions, the tenacious oxide layer on magnesium metal has limited the scope of research to halide ion-based electrolytes, which help activate the electrode surface but also limit the working voltage window considerably and can cause pitting and corrosion to parts commonly used in coin cells. Here we discuss our efforts at developing new halide-free magnesium ion electrolytes based on fluoroalkoxyaluminate anions synthesized via a facile and scalable method and its incorporation in a full battery cell. Our results show a large voltage window on stainless steel and aluminum (4-5 V vs. Mg), high conductivity (comparable with lithium ion electrolytes), and near unity Coulombic efficiency. We will discuss characterization of the electrolyte, identity of solution species, and promising methods of modifying the electrolyte for improved figures of merit.
An Au-[Fe-S]-NAD-Glucose Dehydrogenase Bioanode for Glucose Detection
Authors: Mahadevan Aishwarya , Fernando Sandun
Published: February 2020

Immobilization of NAD-dependent redox enzymes on electrode surfaces has been widely reported for the construction of enzymatic biosensors for detection of various biomolecules in different industries. Molecular wiring of such redox enzymes facilitate an efficient electron transfer by connecting redox center of the enzyme with the electrode surface. Iron-sulfur complexes are known for being the firstlink between protein and the mediating molecules in the mitochondrial electron transport chain to abstract electrons from NAD+. The application of iron-sulfur molecules as molecular wires to mediate electron transport between NAD-dependent glucose dehydrogenase (NAD-GDH) and gold electrode surface (i.e. a glucose bioanode) was studied. Methodology for fabrication and characterization of iron-sulfur based glucose biosensor at different construction stages were described. The biosensor performance characteritics of the novel Fe-S based glucose biosensor was investigated using amperometric analyses in the presence of glucose.
All Organic Screen Printed Electrodes for Continuous Recording of Electrocardiogram
Authors: Sinha Sneh Kumar , Noh Yeonsik , Treich Gregory Martin , Reljin Natasa , Hajeb-Mohammadalipour Shirin , Chon Ki , Sotzing Gregory Allen
Published: February 2020

Electrocardiography (ECG) is an essential technique for analyzing the proper electrical functioning of heart. Traditionally Ag/AgCl electrodes have been used for monitoring ECG signal from the body. However, Ag/AgCl is known to cause skin irritation on prolonged usage and measurements cannot be done in wet conditions. Conjugated polymers, with their mixed ionic and electronic conduction, offer an alternative to Ag/AgCl. This work provides an easy to fabricate ECG sensor from commercially available PEDOT:PSS using screen printing technique onto a commercially sold T-shirt. ECG signals from screen printed PEDOT:PSS electrodes were recorded during motion at a heart rate of up to 180 bpm. Variation of ECG signal amplitude vs impedance of electrodes was studied. In addition, PEDOT:PSS was also demonstrated to work as an organic wire for copper lead replacement used in recording ECG signals. Reusability of the shirt was demonstrated by recording ECG signal under active exercise even after 3 wash cycles and subsequent drying.

Figure 1
Stress Detection Using Polymer Optical Fiber with FRET Pair Dyes
Authors: Furukawa Rei , Kamimura So
Published: February 2020

Noble fiber-optic strain sensor using dye-doped polymer optical fiber (POF) was proposed, and its ability to sense stress (strain) by simple viewing of the large-core cross section was proposed. Conventional well-known fiber-optic strain sensors such as BOTDR or FBG types require spectral analysis to determine the strain value. Our sensor does not require expensive equipments such as spectral analyzer or well-tuned light source that are required in conventional fiber-optic strain sensors.

A pair of luminescent organic dyes, Coumarin 540A and Rhodamine 6G, that functions as donor and acceptor of excitation energy were doped in core and cladding of the fiber, respectively. By taking this structure, stress applied to the fiber could be detected as an increase in cladding intensity. This happens because emission of core dye leaks to the cladding due to the deformation, and it excites the cladding dye.

Using the fabricated POF, change in near field pattern upon different fiber bending diameter was detected. Lasers with three different wavelengths were used; namely, 406 nm, 532 nm, and 635 nm. 406 nm is the optimum wavelength for exciting the Coumarin 540A of the core efficiently. 532 nm excites Rhodamin 6G well, but does not excite Coumarin 540A well. 635 nm excites neither dyes. Pigtail end was coupled to the test fiber with direct contact to the core center of the test fiber in which no cladding excitation was expected. Fibers were stressed in various magnitudes by bending them in different loop diameters, namely, 1.5 cm, 3 cm, and 6 cm. Single loop was created in the middle point of the whole length. Relaxed condition, which the fiber was naturally straightened with no loop, was also investigated. Output beam from the test fiber was analyzed using Near Field Pattern measuring system (Hamamatsu C9664-01G02).

In addition, dye-doped POF with lower numerical aperture had shown enhancement in sensitivity. Therefore, it was suggested that sensitivity of the sensor is controllable by further optimization of the waveguide parameters. Therefore, the proposed results suggests a potential for an enhanced fiber-optic stress detection with simpler and inexpensive accessory components.
Synthesis and Characterization of NiO Nanostructures Formed By Anodization Sonoelectrochemical. Its Application As Non-Enzymatic Glucose Sensor
Authors: Schrebler Ricardo Silvio , Grez Paula , Heyser Cristopher Alejandro
Published: February 2020

The electrochemical determination of glucose concentration through the use of a non-enzymatic system is a priority purposes in recent decades. For this reason, many researchers have focused their studies on the development of sensors of this nature. For this purpose, they have proposed the use of new materials such as metals and metal oxides. In this context, we conducted a study of the synthesis and characterization of the electrical and morphological properties of nickel oxide (II) type - p (p-NiO), all this in order to evaluate it as a possible nonenzymatic sensor glucose molecule. Despite the above, the nickel oxide has a low diffusion rate of charge carriers. Therefore, new synthesis routes leading to a nanostructured oxide is required, so that the photogenerated electrons are accumulated in the vicinity of the surface. This is to facilitate the transfer process of charge per on the recombination. This report shows the results concerning the preparation sonoelectrochemical of NiO nanostructures (NN). Nanostructured NiO layers have been electrochemically grown by ultrasound-assisted anodization of nickel foils (Advent, 99.0%, 0.1 mm) at a potential of 50 V in ethylene glycol (EG; 99.8%, anhydrous), ammonium fluoride (0.5 wt% NH4F) and wt 5.0% DI water. The anodization experiments were carried out using ultrasonic waves (37 kHz, 60 W) and were carried out for 300 s at different temperatures. The above process was carried out using a two-electrode system (flag shaped 1.0 cm2 Ni foil as anode and carbon plate, 22.55 cm2 as cathode; the distance between cathode and anode was kept at 3 cm). Two different nickel substrates have been assayed, i.e.: (i) bare nickel foils, and pre-treated nickel substrates by anodic polarization for 2 hours in a 0.1 M KX (X = F- o Cl-) in aqueous solution at -0.18 V. The resulting NiO nanostructures (NN) will then be named as: NN(w/o) and NN (−0.18 V), respectively. The electrochemical pretreatment process of nickel substrates was carried out using a conventional electrochemical cell with a three-electrode arrangement. As a reference electrode, an Hg/Hg2SO4 (SME, 0.650 V vs. NHE) has been used, and a platinum spiral and a nickel sheet of 1.0 cm2 constituted the counter and working electrode, respectively. The anodized samples are properly washed with distilled water, to remove the occluded ions, and dried in a furnace. Moreover, nanostructured NiO layers obtained were analyzed morphologically by atomic force microscopy (AFM), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). The results obtained for nickel oxide as a non-enzymatic glucose sensor are preliminary and are being analyzed by authors.
A Comparison of Thiospinel Mg Battery Cathode Materials: MgxTi2S4 and MgxZr2S4
Authors: Bonnick Patrick , Sun Xiaoqi , Blanc Lauren , Nazar Linda F
Published: February 2020

The search for batteries with higher volumetric energy densities than conventional Li-ion batteries has led to the pursuit of several new technologies including rechargeable Mg batteries. Mg metal is attractive as a negative electrode material because it has a higher volumetric capacity density (3833 mAh/mL) than Li metal (2062 mAh/mL), is the 8th most abundant element in the earth’s crust, is safe to handle in ambient atmosphere, and can be electrodeposited (charged) without the formation of dendrites.1 The seminal work by Aurbach et al. in 20002 established an electrolyte and a positive electrode material, the Chevrel phase (Mo6S8), that was paired with Mg metal to form the first rechargeable Mg battery.

Mg2+ intercalation in host materials is more difficult than that of Li+ or Na+, displaying lower ion mobility in solid oxide hosts,3 a tendency toward conversion reactions,4 and a possibly higher desolvation energy penalty.5 In fact, the second material to reversibly intercalate Mg2+, without debilitating decomposition over more than 100 cycles, was only demonstrated last year: the thiospinel Ti2S4.6 Unfortunately, our attempts to insert (or remove) Mg2+ into other 1st row transition metal thiospinels were unsuccessful; however, Mg2+ can be reversibly intercalated from thiospinel Zr2S4, a 2nd row transition metal.

Figure 1 shows the 1st discharge and charge of two coin cells using Mg foil anodes, Mg(CB11H12)2 in tetraglyme electrolyte and either a MgxTi2S4 or MgxZr2S4 electrode. We will present a comparison of the Mg intercalation into the Zr2S4 and Ti2S4 thiospinels, including Mg site occupancy, cell parameter variation, and Mg diffusion coefficients. In doing so, we will explore the crucial parameters that allow facile Mg2+ diffusion for consideration when designing new Mg2+ intercalation materials.

References

J. Muldoon, C. B. Bucur, and T. Gregory. Chem. Rev.
114, 11683-11720 (2014).

D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich and E. Levi. Nature
407, 724-727 (2000).

E. Levi, Y. Gofer, and D. Aurbach. Chem. Mater.
22, 860-868 (2010).

P. Canepa, G. Sai Gautam, D.C. Hannah, R. Malik, M. Liu, K.G. Gallagher, K.A. Persson and G. Ceder. Chem. Rev.
117, 4287-4341 (2017).

L. F. Wan, B. R. Perdue, C. A. Apblett and D. Prendergast. Chem. Mater.
27, 5932-5940 (2015).

X. Sun, P. Bonnick, V. Duffort, M. Liu, Z. Rong, K.A. Persson, G. Ceder and L. F. Nazar. Energy Environ. Sci.
1, 297-301 (2016).

Figure 1
Influence of Inversion on Mg Mobility and Electrochemistry in Spinels
Authors: Gautam Gopalakrishnan Sai , Canepa Pieremanuele , Urban Alexander , Bo Shou-Hang , Ceder Gerbrand
Published: February 2020

Spinels are an important class of compounds in energy-dense multivalent batteries with potential cathode (MgMn2O4) and solid electrolyte (MgIn2S4) applications. Both MgMn2O4 and MgIn2S4 are susceptible to inversion, which is the exchange of Mg and metal (Mn/In) sites in the spinel framework. Using first-principles calculations, we evaluate the impact of spinel Inversion, which can directly lead to several distinct local cation environments, on Mg2+ mobility. While activation barriers for various cation decorations determine the active Mg2+ diffusion channels on the atomic scale, the macroscopic migration of Mg2+ is essential for (dis)charge of cathodes or ionic conduction in solid electrolytes. Subsequently, we perform Monte-Carlo simulations to estimate the minimum Mg concentration required to ensure Mg2+ percolation through the spinel structure. Finally, we analyze the influence of inversion on the electrochemical properties of the MgMn2O4 cathode by investigating the phase behavior, average voltages and extractable capacities at various degrees of inversion.
Designing New Magnesium-Based Cathode Materials
Authors: Vaughey John T. , Key Baris , Proffit Danielle L. , Sa Niya , Ingram Brian J. , Lipson Albert L. , Poeppelmeier Kenneth , Incorvati Jared T
Published: February 2020

Lithium-ion batteries have been a mainstay of the consumer electronics industries for nearly 25 years. Unlike many older energy storage systems, lithium-ion does not describe a specific chemistry but a family of chemistries and a mechanism of operation. As a result numerous types of materials are under the umbrella of lithium-ion batteries that can be modified and developed to meet a variety of end-user goals. Looking beyond-lithium ion, the landscape is less understood and explored. One of our research efforts is to look at non-lithium cation based energy storage chemistries, including the MgxV2O5 and MgxV2O5*H2O systems. This talk will focus on recent developments from our lab in Mg-ion and Ca-ion chemistries with highlighting new types of cathodes, electrolytes, and anode materials1-5

References

(1) Lipson, A.L; Han, S.-D; Kim, S. Pan, BF; Sa, N.; Liao; C, Fister, TT; Burrell, AK; Vaughey, JT; Ingram, BJ J. Power Sources
325 646-652 (2016).

(2) Sa, N; Wang, H; Proffit, DL; Lipson, AL; Key, B; Liu, M; Feng, ZX; Fister, TT; Ren, Y; Sun, CJ; Vaughey, JT; Fenter, PA; Persson, KA; Burrell, AK J. Power Sources
323 44-50 (2016).

(3) Sa, N; Kinnibrugh, TL; Wang, H; Gautam, GS; Chapman, KW; Vaughey, JT; Key, B; Fister, TT; Freeland, JW; Proffit, DL; Chupas, PJ; Ceder, G; Bareno, JG; Bloom, ID; Burrell, AK Chemistry of Materials, 28(9) 2962-2969 (2016).

(4) Lipson, AL; Han, SD; Pan, B; See, KA; Gewirth, AA; Liao; Vaughey, J; Ingram, BJ J. Electrochem. Soc.,
163(10) A2253-A2257 (2016).

(5) Mukherjee, A.; Sa, N.; Phillips, P.; Burrell, AK; Vaughey, JT; Klie, R. Chemistry of Materials, 29, 2218−2226 (2017).

Figure 1
Ultrasonically Dispersed Sodium Powders As Electrode Additives for Improved Cycling of Sodium Ion Batteries
Authors: Tang Jialiang , Kye Daniel Kyungbin , Pol Vilas G.
Published: February 2020

Solid electrolyte interphase (SEI) growth on the anode surface remains a major challenge to sodium ion batteries. Excessive SEI buildup in the formation cycles or later cycles would consume electrolyte, deplete available alkaline ions, and increase cell polarization. These issues with SEI growth become more prominent in full cells in which cathodes store limited amount of alkaline ions that are available for electrochemistry. The reduction in the amount of available alkaline ions upon cycling often results in low capacity and poor capacity retention in full cells. To compensate the Na loss from SEI formation, we developed a sodium powder based presodiation technique that could potentially be applied to both anode and cathode materials with minimal modification to conventional battery making process. The synthesis of sodium powders is accomplished via ultrasonic dispersion of molten sodium in mineral oil. When suspended in hexane, the sodium powders can be easily applied onto electrodes as presodiation additives. Reduction in the 1st cycle loss and enhancement in reversible capacity have been observed in this study.