bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutrons for Battery Research (in-situ and operando studies): An Overview
Authors: Gilles Ralph , Gasteiger Hubert A. , Gernhäuser Roman , Hattendorff Johannes , Jossen Andreas , Märkisch Bastian , Révay Zsolt , Seidlmayer Stefan , Trunk Markus , Werner Lukas , Weydanz Wolfgang 
Published: December 2020

The further development of battery materials and cells must go hand in hand with improved in-situ and operando characterization methods. Such techniques provide a better and deeper understanding of the mechanisms to determine even minor changes in cell components and their impact on the overall performance of cells and their capacity or battery life.
The last ten years there has been a great deal of interest in scattering techniques for examining battery components and in particular complete cells [1]. Neutrons as a probe or techniques derived from neutrons play a special role in this development because their unique properties and possibilities are very well suited for battery research. On the one hand, neutrons can penetrate deep into materials and on the other hand, they are very sensitive to light elements as Li, H or N. In addition, neutron methods are non-destructive, which makes it possible to measure the inner part of a cell as well as to perform operando measurements. Improvements of neutron instrumentation including coatings of neutron guides, higher counting rates of detector systems and dedicated sample environments. Further the higher neutron flux of modern neutron large scale facilities accelerate the development of neutrons for battery research. In-situ and operando studies while changing external parameters such as charging/discharging or temperature change etc. are carried out to examine cells under real working conditions.
Neutron diffraction, small-angle neutron scattering, neutron imaging and neutron depth profiling are considered among the most suitable methods for battery research. This contribution presents typical applications of these different neutron methods, which are used on different length scales. Neutron diffraction and small-angle neutron scattering are suitable to investigate changes from the atomic scale up to the mesoscopic scale (~ 300 nm). Processes such as Li intercalation in graphite anodes during battery charging can be described in detail [2,3]. Neutron imaging is suitable to follow in-situ the electrolyte filling process in hard case cells [4]. The neutron depth profiling technique is applied for studies of the Lithium mobility at the different electrode interfaces to determine the Li concentration profile in approximately the first 50 mm [5], e.g. the SEI layer [6].

Reference
s
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[1] R. Gilles, Journal of Surface and Investigations: X-ray, Synchrotron and Neutron Techniques (2020), in print.
[2] V. Zinth et al., Journal of Power Sources 361 (2017) 54-60.
[3] J. Hattendorff et al., J. Appl. Cryst. (2020), 53, 210-221.
[4] W. J. Weydanz et al., Journal of Power Sources 380 (2018) 126-134.
[5] M. Trunk et al., Materials Characterization (2018), 146, 127-134.
[6] S. Whitney et al., Journal of the Electrochemistry Society (2009), 156(11) A886.
Quantitative Concentration Mapping with AFM-SECM
Authors: Mirabal Alex , Calabrese Barton Scott 
Published: December 2020

Efficient transport of reaction intermediates between active sites can improve the efficiency of multi-site reactions.1–3 Experimental detection of these nanometer length scale transport mechanisms is enabled by Scanning Electrochemical Microscopy (SECM). Electrochemical measurements can allow for concentration profile mapping to elucidate the transport processes in experimental systems. SECM can correlate position dependent responses to properties of the system. There is a significant impact on the response profile due to the SECM tip’s presence at the nanoscale. Finite Element Analysis (FEA) has been used to understand and remove these in situ tip effects.
The calculated concentration, using current-flux relations, can be complex near sites generating flux through reactions and/or transport. Additionally, uncertainties such as tip positioning in relation to the interface site can further complicate the response. Quantitative concentration fields can more readily be interpreted through FEA, by matching the experimental tip response.
Electrodeposited platinum nanoparticles were imaged topographically and electrochemically with a Bruker AFM-SECM (Figure 1). The positive response over the nanoparticles vs. the planar HOPG sites allows for kinetic response imaging. The model is parameterized through approach curves and verified though SECM mapping correlation.
We have previously applied FEA to correlate experimental in situ results to in operando conditions through a non-linear regression of approach curve responses. Here, we use this approach to generate corrected concentration profiles. We use Pt nanoparticle catalysts deposited on HOPG, to develop surface property correlations. In this way, a comparison can be drawn between in situ and in operando approaches.

References

(1) Schuhmann, W. Amperometric Enzyme Biosensors Based on Optimised Electron-Transfer Pathways and Non-Manual Immobilisation Procedures. Rev. Mol. Biotechnol. 2002, 82 (4), 425–441.
(2) Wheeldon, I.; Minteer, S. D.; Banta, S.; Barton, S. C.; Atanassov, P.; Sigman, M. Substrate Channelling as an Approach to Cascade Reactions. Nat. Chem. 2016, 8 (4), 299–309.
(3) Liu, Y.; Hickey, D. P.; Guo, J. Y.; Earl, E.; Abdellaoui, S.; Milton, R. D.; Sigman, M. S.; Minteer, S. D.; Calabrese Barton, S. Substrate Channeling in an Artificial Metabolon: A Molecular Dynamics Blueprint for an Experimental Peptide Bridge. ACS Catal. 2017, 7 (4), 2486–2493.

Figure 1
Scanning Electrochemical Cell Microscopy; Measurement Process Optimization to the Electrochemical Response Based on Experimental Parameters
Authors: Cho Sang-Joon , Kim Seong‐Oh , Goo Kyo-Suk , Kang Jihoon 
Published: December 2020

As the development of scanning probe microscopy (SPM) continues, the spatial resolution and sensitivity for various material properties steadily improve. Therefore, SPM images morphological features as well as electrical, mechanical, magnetic, and chemical properties with a nanoscale resolution. Among the various SPM techniques, pipette-based SPM offers new possibilities and insights into the sample’s electrochemical properties. Since the invention of scanning electrochemical microscopy (SECM), the first-generation pipette-based SPM for electrochemical measurement, it has been extensively used in many research fields, e.g. for visualizing chemical reactions at surfaces and interfaces. However, the difficult distance control between the pipette probe and the sample surface limits the application of SECM.
Here, we introduce scanning electrochemical cell microscopy (SECCM): a latest pipette-based SPM method, which investigates electrochemical responses on target materials in a point-by-point approach using the ionic current for distance control. We present experimental and theoretical data on contributing factors to the electrochemical response, including pipette configuration, redox species, scan rate and choice of substrate. A variety of pipette inner diameters (range from ~150 nm to ~ 1 μm), buffer concentrations, and voltammetric sweep rates are reviewed using well-defined conductive substrates and electrodes. Based on our results, we propose optimized experimental parameters for various measurement conditions. We believe that SECCM has great potential in providing new insights to electrochemical properties of surfaces and interfaces required for research on chemical energy storage, among others.

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(Keynote) Mechanistic Studies of the Electrochemical CO2 Reduction on Single Site, Metallic and Hybrid Electrocatalysts
Authors: Strasser Peter 
Published: December 2020

The science and technology of the direct electrochemical CO2 reduction reaction on both model-type solid catalytic surfaces and Gas Diffusion Electrodes (GDEs) inside electrolyzers offer as many formidable challenges as intriguing opportunities. Controlling the selectivity (faradaic efficiency), while maximizing the energy efficiency by lowering the kinetic overpotentials remains key to turn this complex reaction into a practical process embedded in a process chain. To achieve this, deeper mechanistic understanding of surface catalytic reaction pathways by means of time-resolved kinetic characterization of the production rates of major and minor reaction products is needed.
In this talk, I will highlight some of our recent advances in the understanding of the chemical mechanism of the direct electrochemical reduction of CO2 and of related mixed feeds into value-added fuels and chemicals on metallic surfaces, on non-metallic, single metal-site electrocatalysts, and on metallic/non-metallic tandem catalyst schemes. Apart from in situ X-ray analytical techniques, focus was placed on new insights using time-resolved Differential Electrochemical Mass Spectrometry (DEMS) conducted in capillary inlet flow cells. These studies enable milli-second resolved analysis of reaction products under stationary and transient conditions, and thus provide access to accurate onset potentials of reaction products. Computational mechanistic predictions are tested by experiments and plausible reaction pathways and intermediates and their binding is discussed. Metallic catalysts comprise Cu and Cu-based alloys, while non-metallic single site catalysts include high surface-area solid carbons with atomically dispersed, nitrogen-coordinated metal atom moieties.
(Invited) Hybrid Mixed-Metal-Oxide-Based Catalytic Systems for Efficient Electroreduction of Carbon Dioxide
Authors: Rutkowska Iwona , Kulesza Pawel 
Published: December 2020

Of particular interest to the preparation of advanced catalytic materials is efficient utilization of nanosized materials with well-defined composition, structure and thickness that exhibit desirable electrocatalytic properties. There has been growing interest in the electrochemical conversion of carbon dioxide (a potent greenhouse gas and a contributor to global climate change) to useful carbon-based fuels or chemicals. Given the fact that the CO2 molecule is very stable, its electroreduction processes are characterized by large over-potentials. It is often postulated that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate. In this respect, the proton availability and its mobility at the electrochemical interface has to be addressed. On the other hand, competition between such parallel processes as hydrogen evolution and carbon dioxide reduction has also to be considered.
We explore here the ability of polynuclear inorganic metal oxo systems to stabilize and derivatize metal and carbon nanostructures. Here certain nanostructured metal oxides of zirconium, titanium, molybdenum or tungsten have been demonstrated to influence supported metal centers in ways other than simple dispersion over electrode area. Evidence is presented that the support can modify activity (presumably electronic nature) of catalytic metal nanoparticles (e.g. Cu, Ru), thus affecting their chemisorptive and catalytic properties. Metal oxide (WO3, MoO3, TiO2) nanospecies can generate –OH groups at electrocatalytic interface.
Our electrocatalytic results with copper-substituted polytungstates (or polyoxometallate-network-stabilized copper oxo assemblies)and with copper nanostructures over-coated with WO3 or MoO3 nanostructures imply improved selectivity toward CO2-reduction relative to the competitive hydrogen evolution as well as lower tendency of copper sites to undergo poisoning. We believe that the partially reduced WO3 or MoO3 are capable of sorption of hydrogen, or shifting the proton discharge toward more negative potentials, rather than inducing hydrogen evolution.
(Keynote) Electrodeposited Catalysts for High Efficiency CO2 Electrolyzers
Authors: Chen Xinyi S. , Gewirth Andrew A. 
Published: December 2020

This talk addresses the reactivity associated with CO2 reduction. Electrodeposition of metals from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor yields highly porous materials exhibiting enhanced activity for electrochemical reactions. Electrodeposition of CuAg or CuSn alloy films from such plating baths yields high surface area catalysts for the active and selective electroreduction of CO2 to multi-carbon hydrocarbons and oxygenates. Alloy films containing Sn exhibit greater efficiency for CO production relative to either Cu along or CuAg at low overpotentials. In-situ Raman and electroanalysis studies suggest the origin of the high selectivity towards C2 products to be a combined effect of the enhanced stabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag or Sn incorporated in the alloy. Sn-containing films exhibit less Cu2O relative to either the Ag-containing or neat Cu films, likely due to the increased oxophilicity of the admixed Sn.
In order to further control surface oxygen content we developed a copper-polyamine hybrid catalyst that significantly increases the selectivity for ethylene production. The Faradaic efficiency for ethylene production is 87% ± 3% at -0.47 V versus reversible hydrogen electrode, with a full-cell energetic efficiency reaching 50% ± 2%. Raman measurements indicate that the polyamine entrained on the Cu electrode results in higher surface pH, higher CO content, and more stabilized intermediates relative to entrainment of additives containing little or no amine functionality. This work shows that polymer incorporation can install functional groups onto an electrode surface, alter surface reactivity, and lead to enhanced product selectivity.
Electrochemical Pumping Behavior of an Anion Exchange Membrane CO2 Separation Device
Authors: Muroyama Alexander Paul , Patru Alexandra , Pribyl Bernhard , Gubler Lorenz 
Published: December 2020

Anion exchange membranes (AEM) are well studied in the context of fuel cells and water electrolyzers, as they permit the use of non-noble catalysts. However, such alkaline systems have a notable drawback of carbonation when they are operated using atmospheric air, which is known to reduce the anion conductivity of the membrane. The (bi)-carbonate ions are removed from the membrane through the migration of hydroxide ions, also known as the self-purging mechanism. This carbonation effect of AEMs can be utilized to selectively remove CO2 from a dilute gas mixture (e.g., flue gas or air) and transport it across the membrane, as shown in Figure 1.
Effective CO2 transport across the membrane can be enabled using hydrogen evolution and oxidation reactions in the presence of CO2 and alkaline media. This methodology differentiates itself from other membrane-based separation techniques, as it allows for low concentrations (<1%) of CO2 to be removed at a high fraction (>90%) from a gas stream. Significant developments are required to optimize such a system, reduce material costs and cell overpotentials, and allow for long-term operation.
We performed preliminary experiments proving the concept of an electrochemical CO2 separation device utilising AEMs. Steady-state galvanostatic experiments with on-line non-dispersive infrared gas analysis have demonstrated the clear relationship between current density, cell potential, and CO2 pumped across the membrane for a wide range of inlet CO2 concentrations. Faradaic efficiencies for CO2 transport are strongly dependent on the inlet CO2 concentration and current density. Considerations for further development are discussed.
Figure Caption: Schematic of AEM CO2 separator

Figure 1
Development of Carbon Fiber-Based Ni(OH)2 Electrode for Application in Urea Wastewater Treatment/Hydrogen Production
Authors: Hung Chi-Han , Liu Yi-Hung 
Published: December 2020

Introduction

Urea-containing wastewater is discharged every day from factories, agricultural fertilizers, and human/animal urine, etc. If we do not properly teat it in time, it will cause environmental pollution, health hazards and other problems. Conversely, treating urea-containing wastewater can produce H2 energy source through an electrolysis process [1], which is considered attractive due to its lower electrolysis voltage than that for water splitting. In the past, nickel hydroxide (Ni(OH)2) has been used as a catalyst material for urea oxidation reaction (UOR), because it has several advantages such as cheap and good catalytic effect on urea. However, UOR performance is still not satisfied due to poor material design for electrodes, and thus needs to be improved. In light of this, our research is committed to developing a composite electrode integrating Ni(OH)2, carbon nanotubes (CNTs), and carbon fibers (CFs). The electrode allows to enhance UOR performance, which can simultaneously benefit urea degradation and H2 production.

Experimental

CFs were used as the electrode substrate, and Ni(OH)2 were deposited on the CFs surface together with carbon nanotubes (CNTs), through a one-step electrophoretic co-deposition method. Afterward, the composite was further experienced a hydrothermal reaction to complete the fabrication of the Ni(OH)2/CNT/CF electrode. SEM, XRD, Raman spectroscopy, and TGA were used to examine the material properties of the composite electrode. A three-electrode electrolytic system composed of the composite electrode, a Pt counter electrode, and a Ag/AgCl reference electrode was set up to treat the urea-containing wastewater. During the treatment, cyclic voltammetry and linear sweep voltammetry were applied to investigate the Ni(II)/Ni(III) redox reaction and UOR. Details about the electrode kinetics were also discussed.

Results and Discussion

The experimental results show that the Ni(OH)2/CNT/CF electrode has more favorable UOR performance compared to the Ni(OH)2/CF and CF ones. In addition, the α-Ni(OH)2-phase catalyst is found to present better electrocatalytic activity than the β-Ni(OH)2-phase catalyst. This could be due to larger d spacing of (001) plane in α-Ni(OH)2, allowing more inserted water molecules than those in β-Ni(OH)2. Accordingly, it expedites ion transport between the Ni(OH)2 sheets and repeated Ni(II)/Ni(III) transformation during continuous UOR [2], corresponding to better electrochemical performance. On the other hand, doping CNTs is found to benefit the increased reaction area and electrical conduction of the composite electrode. As a result, the required overpotential for UOR is reduced and the reversibility of Ni(II)/Ni(III) redox reaction is improved, leading to more efficient UOR.

References

[1] B. K. Boggs, R. L. King and G. G. Botte, Chem. Commun., 32, 4859–4861 (2009).
[2] C. Lin, Z. Gao, F. Zhang, J. Yang, B. Liu and J. Jin, J. Mater. Chem. A, 6, 13867–13873 (2018).
Optical Trapping Raman Spectroscopy As a Sensor / Actuator / Treatment System
Authors: Bertz Morten , Molinnus Denise , Schoening Michael J. , Homma Takayuki 
Published: December 2020

In recent years, Raman spectroscopy has evolved into a broadly used analytical method in chemistry, life sciences, and medicine. Here, we combine Raman spectroscopy with optical trapping and optical microscopy to isolate and investigate individual micron-size biological particles from a sample. In this setup, Raman spectroscopy provides a label-free chemical fingerprint while light microscopy reveals the sample morphology. In addition, elastic light scattering as well as observation of diffusive movement in the optical trap’s potential offer information on particle size and refractive index. Single particles can be captured and manipulated for tens of minutes. During this time, the stably trapped particles can be exposed to a variety of chemical and physical stimuli such as heat, light of different wavelengths, or changes in the chemical composition of the particle environment through microfluidics (Fig. 1A).
In this work, we employ this optical trapping Raman spectroscopy sensor / actuator / treatment system to study the effect of hydrogen peroxide (H2O2) on individual spores of Bacillus atrophaeus, an important model system to assess the efficacy of industrial sterilization processes. Interestingly, we find B. atrophaeus spores to be stable for more than 30 minutes while optically trapped even at elevated temperatures (> 70 °C). Exposure to H2O2 results in spore degradation in a concentration-dependent manner within several minutes and is accelerated by high temperatures. Raman spectroscopy indicates that spore degradation is characterized by the rupture of the spore core resulting in the fast release of dipicolinic acid, a major spore biomarker that is considered key for spore resistance to environmental stress (Fig. 1B). Oxidative degradation of the spore shell starts before core rupture and continues after dipicolinic acid release. Simultaneous observation of spore morphology corroborates this two-phase model. Illumination with shorter (< 550 nm) wavelength light exposes the spores to oxidative stress via the generation of reactive oxygen species in the spore environment by light, thereby mimicking the H2O2 sterilization process. In the presence of small amounts (0.5%) H2O2, spore lifetime is reduced to several seconds.
With the presented system, we address spore activity down to the single cellular level in a multimodal manner: trapping and manipulation of single spores over several tens of minutes (actuator functionality), stimulation of single spores by temperature, illumination, and H2O2 exposure (treatment functionality) as well as on-line monitoring of spore activity (sensor functionality).

Figure 1