bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering on Ni-Co-S Bifunctional Electrocatalyst for Water-Splitting
Authors: Wu Jing 
Published: February 2020

Efficient evolution of hydrogen and oxygen simultaneously with earth-abundant, highly active, and robust bifunctional electrocatalysts has been a significant concern for water splitting. Herein, non-noble metal based Ni-Co-S bifunctional catalysts with tunable stoichiometry and morphology were realized. The electronic structure engineering and subsequent morphological design synergistically contributed to significantly elevated electrocatalytical performance. Overpotentials η10 of 243 mV (vs.RHE) for OER and 80 mV for HER in 1M KOH solution, as well as Tafel slopes of 54.9 mV/dec for OER and 58.5mV/dec for HER were demonstrated together with prominent stability. In addition, DFT calculation was conducted to indicate the optimal electronic structure via visually mapped electron density difference of catalysts, and representatively verify that the enhanced OER activity of NiCo2S4 nanosheets is concerned with the Co top site on (110) surface. Moreover, the tandem bifunctional NiCo2S4 anode and cathode exhibited a required voltage down to 1.58V (J=10 mA/cm2) for simultaneous OER and HER, and no obvious performance decayed after 72 h. When integrated with a GaAs solar cell, such photo-assisted water splitting electrolyzer acquired a certificated solar-to-hydrogen efficiency up to 18.01%, further demonstrating the feasible engineering protocols as well as the promising potential of bifunctional NiCo2S4 for large-scale overall water splitting.[1, 2]

References

[1] H. Kim, K. Kang, et.al.,
Nat. Commun.
2015, 6, 8253.
[2] H. Wang, Y. Cui, et.al., Nat. Commun. 2015, 6, 7261.
Understanding the Active Sites and Reaction Mechanism for Water Oxidation on Ruthenium Dioxide
Authors: Rao Reshma R , Shao-Horn Yang 
Published: February 2020

Rutile Ruthenium Dioxide (RuO2) is a gold standard catalyst for water splitting in acidic solutions1-3. It can also undergo fast surface redox reactions in the electrochemically stable potential window of water, making it an ideal material for electrochemical capacitors that can charge and discharge in a much shorter time scale than batteries. However, there is a lack of fundamental understanding of the active sites and atomic scale processes occurring at the oxide-electrolyte interface upon interaction with water as previous work has been confined to the ultra high vacuum environment, and to the thermodynamically stable (110) surface4.
In this work, we use three different facets of RuO2, (110), (100) and (101) to demonstrate how changing the local environment of surface Ru and O atoms can enable tuning the electronic structure of the active site and alter its intrinsic oxygen evolution reaction (OER) activity. Using synchrotron based ambient pressure X-ray photoelectron spectroscopy and in situ surface diffraction on single crystal surfaces coupled with density functional theory calculations, we show that at 1.0 VRHE, water adsorbs molecularly or dissociatively on the coordinatively unsaturated site (CUS), depending on the surface orientation. This is followed by successive deprotonation occuring at potentials greater than 1.0 VRHE . At oxygen evolution potentials (1.5 VRHE), surface diffraction measurements reveal the presence of an –OO species on the CUS site for the (110) and (100) surface. Computation results show that this –OO group is stabilized by a neighboring –OH group suggesting that the final deprotonation step is rate-limiting. On the other hand, for the (101) surface that binds oxygen more weakly, a completely oxidized surface has been detected, implying a change in the rate-limiting step to the dissociation and deprotonation of the second water molecule on the oxidized surface. The mechanistic insight gained from in situ methods will be used to discuss the difference in OER activity and Tafel slope observed on the different RuO2 facets. Finally, the results obtained using single crystals will be extended to understanding the distinct redox peaks of RuO2 nanoparticles in the electrochemically stable potential window of water as well as the nature of intermediates prior to the evolution of oxygen. Thus, by using different experimental and theoretical techniques on model surfaces, this study identifies the active sites for oxygen electrocatalysis and demonstrates how catalyst surface structure can be altered to improve OER kinetics.

References:

[1] Trasatti S. Electrochimica Acta. 1984;29(11):1503-1512.
[2] Lee Y, Suntivich J, May KJ, Perry EE, Shao-Horn Y. The Journal of Physical Chemistry Letters. 2012;3(3):399-404.
[3] Stoerzinger KA, Qiao L, Biegalski MD, Shao-Horn Y. The Journal of Physical Chemistry Letters. 2014;5:1636-1641.
[4] Over H. Chemical Reviews. 2012;112(6):3356-3426.
Real-Time Characterization of Electrochemical Reaction Products
Authors: Khanipour Peyman , Löffler Mario , Reichert Andreas M. , Kloth Ricarda , Mangoufis-Giasin Iosif , Mayrhofer Karl J. J. , Katsounaros Ioannis 
Published: February 2020

The classical way to characterize the selectivity of electrochemical reactions involves potentiostatic or galvanostatic electrolysis and intermittent product determination, for example with chromatography methods, nuclear magnetic resonance etc.1-3 The advantage of this approach is that quantitation is possible in terms of (partial) reaction rates, yields, selectivities or faradaic efficiencies. However, the offered temporal resolution is in the order of several minutes, so transient, dynamic processes that occur
within seconds cannot be captured. Differential electrochemical mass spectrometry was previously developed to address this point and was applied successfully to a wide range of reactions that form highly volatile or gaseous products.4

A newly developed, internationally unique methodology will be presented that allows for the detection of electrochemical reaction products in real time, independent of their vapor pressure and the presence of salts.5 Some examples of applying the electrochemical real-time mass spectrometry (EC-RTMS) in multi-product electrochemical reactions such as the CO2 reduction, the oxidation of alcohols or conversions of furanic compounds will be shown.

Acknowledgments

This work was funded by the German Federal Ministry for Education and Research (BMBF) under the project grants 033RC004C (eEthylen) and 03SFK2Z0 (Power-to-X), and by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - Excellenzcluster 2186 “The Fuel Science Center”.

References

[1] K.P. Kuhl, E.R. Cave, D.N. Abram, T.F. Jaramillo; Energy Environ. Sci.
2012, 5, 7050-7059.
[2] C.W. Li, J. Ciston, M.W. Kanan; Nature
2014, 508, 504-507.
[3] R.S. Sherbo, R.S. Delima, V.A. Chiykowski, B.P. MacLeod, C.P. Berlinguette, Nat. Catal.
2018, 1, 501-507.
[4] H. Baltruschat, J. Am. Chem. Soc. Mass Spec.
2004, 15, 1693-1706.
[5] P. Khanipour, M. Löffler, A.M. Reichert, F.T. Haase, K.J.J. Mayrhofer, I. Katsounaros; Angew. Chem. Int. Ed. accepted, DOI: 10.1002/anie.201901923
Microelectrode Based Devices for Diagnosis of Electron Transport and Electrochemical Behavior of Redox-Conducting Materials
Authors: Kulesza Pawel J. , Rutkowska Iwona Agnieszka , Miecznikowski Krzysztof 
Published: February 2020

We are going to address practical issues related to the principles and analytical aspects of electrochemical studies (typically done at room temperature) of solid, rigid or semi-rigid (nonfluid) systems in the absence of a liquid solution phase. Representative examples include redox and conducting organic polymers, melts and solid solutions of redox centers in solid ionic conductors, mixed-valence polynuclear inorganic materials, transition metal salts, oxides, and zeolites. The emphasis is on the elements of dynamics for the efficient delivery of charge and on reactivity of the ‘redox conducting’ materials. The effective (apparent) diffusional mechanism is critical to the success of most analytical measurements in solid-state.
Historically, electrochemistry in the absence of a bulk liquid phase has focused on the problems of energy storage and production. Recently, it has become possible to apply conventional electrochemical methods to characterize solid-state type redox electrolytes with respect to analytical characterization of materials, measurement of electron transfer rates, and determination of analytes using amperometric sensing. The characterization of materials by solid-state voltammetry primarily has focused on mixed-valence, ionically conducting compounds and on diverse organic ionomers hosting identifiable molecular (redox) sites.
Potential materials for solid-state electrochemical measurements are expected to contain three-dimensionally distributed highly concentrated redox centers between which fast electron self-exchange (hopping) is feasible. Among inorganic systems, single crystals of heteropolyacids of molybdenum and tungsten, as well thin films of Prussian Blue type metal hexacyanoferrates will be considered. These redox centers are fixed and, although they may have short range mobility about an equilibrium position, they classically are macroscopically immobile. The applicable materials also must host mobile counter-ions that are capable of providing charge balance during electron transfers, thereby serving the same purpose as the supporting electrolytes in conventional electrochemistry. The population of these ions must be sufficient to support diffusive mass transport of electrons and to minimize ohmic effects.
We will describe typical electrochemical cells and experimental tactics to overcome the relatively slow dynamics of transport in solid (non-fluid) systems. Application of microdimensional electrodes leads to an improvement in the quality of solid-state electrochemical data and provides new diagnostic and analytical possibilities. Basic concepts of mechanistic studies, which are relevant to the development of novel analytical methods, together with trends towards possible future applications will also be addressed.
Teaching Engineers in Thin Film Deposition: A Project Based Approach with Applications in Photonics and Laser Technologies
Authors: Steglich Patrick 
Published: February 2020

A lecture model for a practical lecture is proposed, which is intended for a seminar in the master program photonics of the TH Wildau. As part of the seminar, it is important that students have the opportunity to plan the day-to-day tasks of a researcher. The project can be carried out both at the university or/and in companies.
We report on our experience with project-based teaching and provide a novel lecture model which allows students to develop an own research project within one semester.
The envisaged research project is investigated by each student itself and the topic is either defined by the lecturer or by the student himself. The work load of such a research and development (R&D) project is similar to one work package of a real research project. However, to motivate students it is reasonable to divide the R&D project into work packages. This task has to be done within the first two weeks and needs to be instructed by the lecturer.
After the topic and work packages are defined, the student starts to work on its own R&D project. According to our experience, it is worth to provide frequently consultations, e.g. every two weeks. Besides that, a handout with instructions about correct scientific writing is strongly recommended.
Finally, the students will present their results as a written report, a scientific poster and an oral presentation. Some outstanding results are may be published in a scientific journal or conference. This should be motivated by the instructor. In this case, the students have a great starting point for their future career.
We present as an example a R&D project in the field of optical sensors and biosensors.
Electrolytic Zinc Composite Coatings: Ultrasound Assisted Deposition for Morphological and Composition Modification
Authors: Baissac Lucas , Buron Cedric C. , Hihn Jean-Yves , Chantegrel Ludovic 
Published: February 2020

Protection of steel by sacrificial coatings is of primary importance in the industry, to extend the lifetime of steel structure parts. This is frequently obtained by zinc coatings, after galvanization or electrodeposition, but pure zinc is sometimes not resistant enough when high protective properties are required. Indeed, zinc corrosion rate is quite important, even if corrosion products play an important role in protection. Therefore, Zn alloys deposition is a privileged process. However, the metallic alloy elements used for codeposition are frequently composed of harmful substances, which use is more and more regulated. In a global strategy of employees and environment protection, and to anticipate more drastic restriction, the European plating shop leader Electropoli proposed a partnership to the research institute UTINAM. The project Zincadher intended to propose an alternative to zinc alloys plating by a zinc matrix, reinforced by silica and PMMA particles which main function is to increase corrosion resistance and adhesion. To overcome the lack of availability of PMMA (poly (methyl methacrylate)) nanoparticles at a reasonable price, an original synthesis of the PMMA particles was first developed [1]. It involves the use of a custom-made ultrasonic system, were MMA (methyl methacrylate) and water mixtures are exposed to different ultrasonic systems and successive sonication steps as follows: 20 kHz → 580 kHz → 858 kHz → 1138 kHz. Then, polymerization of the droplets is conducted, in order to obtain the largest possible concentration of PMMA particles of sub micrometer size range of different electrokinetic properties [2].
In a second part of the study, electrochemical study of acid zinc electrolyte with PMMA and/or silica particle have been carried out. As ultrasound is known to improve greatly mass transfer and coating characteristics as well as particles dispersion [3], a calibration of acoustic streaming at the surface of the working electrode is conducted, to be able to compare with classical mechanical stirring with the concept of equivalent velocity. Then, after particles dispersion in an acid zinc bath, composite coatings are elaborated. The plating parameters (current density, particles nature, hydrodynamic source…) on the morphology and composition of the coatings are evaluated by SEM/EDS and XRD characterization.
Acknowledgement: The authors would like to thank Electropoli Group for funding this project and the ANRT for the CIFRE convention.
[1] K. Nakabayashi, T. Fuchigami, M. Atobe, Electrochimica Acta. 110 593–598 (2013)
[2] L Baissac, CC Buron, L Hallez, P Berçot, JY Hihn, L Chantegrel, G Gosse Ultrasonics sonochemistry 40, 183-192 (2018)
[3] JY Hihn, F Touyeras, ML Doche, C Costa, BG Pollet in Power Ultrasound in Electrochemistry: From Versatile Laboratory Tool to Engineering Solution, John Wiley & Sons, Ltd, 169-214 (2012)

Figure 1
Micro-Bubble Sonic-Electrochemical Preparation of Polyaniline
Authors: Komaba Kyoka , Goto Hiromasa 
Published: February 2020

Polyaniline is one of the most promising conductive polymers because the polymer can prepared in water medium, no requirement of inert gas in the preparation process. Further, aniline monomer is low cost for production. Polyaniline is prepared by oxidative chemical polymerization with an aid of oxidizing agent such as ammonium persulfate or H2O2 in the presence of iron catalyst, or electrochemical polymerization in the water. Chemical polymerization affords to synthesize polyaniline in the bulk state or powder. However, deposition onto the metal electrode for applications is somewhat difficult because infusible and insolubility in common organic solvent. On the other hand, electrochemical polymerization allows producing thin film deposited onto the electrode. The thin polyaniline film on the electrode is valid for applications such as battery, anti-corrosion films, and gas-sensors.
We recently developed electrochemical polymerization of aniline with bubble air. Nano-bubble has been paid attention for various industrial fields [1]. The polyaniline thus prepared by the micro-bubble electrochemical polymerization has micro-pores on the surface. The size of micro-pores can be tuned by amount and size of micro-bubbles during the polymerization process through tuning of application voltage. The micro-bubble consists of H2 gas as a result of electrolysis of water. Polymerization is occurred during discharge of H2 gas from the anode side with producing micro-pores, resulting polyaniline with micro-pores.
We attempt capture of pollens in the air from the plant with the micro-pores on the polyaniline surface for solution of pollen allergy. The form of micro-pores on the conductive polymer has possibilities for cleaning of air by remove of pollens, removal micro-sands, dusts, oil, and poison gas to improve the environment. Combination of good redox character and the micropores form can lead to construction of electro-active clean up system.
Sonoelectrochemistry has opened a new avenue for electrochemical applications [2,3]. In this paper, we introduce preparation method of polyaniline having micro-pores by micro-bubble electrochemical polymerization with sonic vibration. Surface observation of the polymer with a scanning electron microscopy and discussion of the pore size and effect of the surface state with application of high-power sonic are reported.
References
[1]The latest technology on microbubbles and nanobubbles, Hideki Tsuge ed., CMC, Tokyo, 2007.
[2]J. Mason, J.P. Lorimer, D.J.Walton, Sonoelectrochemistry, Ultrasonics, 28, 333-337 (1990).
[3]J. Klima　Application of ultrasound in electrochemistry. An overview of mechanisms and design of experimental arrangement, Ultrasonics, 51, 202-209 (2011).

Figure 1
Heterogeneity of Ionic Conductivity in Lithium-Ion Battery Electrodes
Authors: Nielsen Kayci , Liu Baichuan , Mazzeo Brian , Wheeler Dean 
Published: February 2020

Lithium-ion battery electrodes are known to have irregularities in their microstructure. When electrodes are not uniform in terms of conductivity, such inhomogeneities can lead to localized variability in current flow, potential, and species concentrations, which are associated with cell degradation [1]. Understanding and quantifying heterogeneity of battery electrodes is therefore an important step in engineering better batteries.
Our research group has previously succeeded in quantifying the variation of electronic conductivity of electrodes using a four-line microprobe [2]. Methods have also previously been developed for measuring the average ionic conductivity of battery electrodes [3], but there was no method for measuring localized ionic conductivity. Our research group recently developed a way to do such a measurement, allowing us to investigate the heterogeneity of effective ionic conductivity across an electrode.
We report the results of local MacMullin Number measurements (proportional to tortuosity or the inverse of conductivity) for various electrodes. We show the heterogeneity of both conventional Li-ion anodes and cathodes and the effect of cycling. In the future, we hope that this technology can be used as a diagnostic tool for improving design and manufacture of electrodes.
Fig. 1. Map of MacMullin Number for a Li-ion cathode
References:
[1] Vogel et al., Electrochimica Acta 297, 820 (2019).
[2] Lanterman et al., Journal of the Electrochemical Society 162, A2145 (2015).
[3] Pouraghajan et al., Journal of the Electrochemical Society 165, A2644 (2018).

Figure 1
Lithium Intercalation Edge Effects and Doping Implications for Graphite Anodes
Authors: Peng Chao , Kramer Denis 
Published: February 2020

The interface between electrolyte and graphite anodes plays an important role for Li intercalation and has significant impact on the charging/discharging performance of lithium ion batteries (LIBs). However, atomistic understanding of interface effects that would allow to rationally tune the interface is largely missed. In this work, we comprehensively study the energetics of Li near the main non-basal surfaces of graphite, namely the armchair and zigzag edges.
Compared with the bulk, both graphite edges provide stronger absorbing Li sites (i.e., sub-surface sites that lithiate at higher voltages). Furthermore, this effect is significantly more pronounced at the zigzag edge compared to the armchair edge due to its unique electronic structure. The “peculiar” topologically stabilized electronic surface state found at zigzag edges strongly interacts with lithium; thereby changing Li diffusion behavior at the surface as well. Finally, boron/nitrogen doping was identified as a promising strategy to tune the Li intercalation behaviors at both edge systems, which might give some guidance for the modification of graphite anodes with a view enhance intercalation kinetics.
Integrated Experiment-Theory Approach to Elucidate Complex Interfacial Chemistry in Solid-State Batteries
Authors: Wan Liwen , Wood Marissa , Wood Brandon C. 
Published: February 2020

All-solid-state batteries offer great promise for safer and higher-energy-density storage compared to conventional liquid-based Li-ion batteries. However, their practical use is hindered by high resistance caused by heterogeneity of structure and chemistry at the solid-state interfaces. To overcome these challenges, atomic-scale visualization of the interfaces and a detailed understanding of the correlation between interfacial structure, chemistry and processing conditions is critical. In this work, we use a combination of first-principles simulation and high-resolution scanning transmission electron microscopy with spatially-resolved electron energy loss spectroscopy to probe complex interfacial structures and chemistry in all-solid-state lithium batteries. We will further address how the processing conditions to prepare the interfaces will affects their structures, local chemistries and Li-ion conductivity through these interfaces.
This work of was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Quenching Cathode Electrolyte Interphase on Ni-Rich Cathode Materials for Preventing Short Circuit Problem in Lithium Ion Battery
Authors: Wang Fu-Ming 
Published: February 2020

In January 2017, Samsung announced the reason why the Note 7 explodes and losses of more than 5 billion US dollar. According to their explanations, it was caused by the internal short circuit problem in the lithium ion battery. Currently, there is no effectively solution for eliminating the internal short circuit problem owing to the sudden accident.
In this research, a new technology has been developed, which can be used to terminate the thermal runaway and promise the safety performance of lithium ion battery. High voltage Li-excess and Ni-rich layer-type cathode material is employed and combined with this safety electrode additive for investigation. In terms of the results, the new technology LIVING@additive significantly enhances the cycle performance at 60oC and high voltage. In addition, the following figures illustrated that the battery containing LIVING@technology is stable and passed the nail penetration test. On the other hand, the battery without LIVING@ cannot be used when the short problem is taking place. The LIVING@contains self-polymerized hyper branch structure in order to insulate the directly contact between anode and cathode. This electrode additive not only provides high thermal stability on electrochemical reaction, but the columbic efficiency of charge-discharge is also enhanced.