bluuebunny/crossref_metadata_2025 huggingface dataset:
Using in Situ X-Ray Diffraction and Coulometry to Understand the Intercalation of Hydrogen into Palladium Thin Films
Authors: Landers Alan Taylor , Koshy David , Lee Soo Hong , Feaster Jeremy T. , Brown Kris , Lin John Christopher , Lee Daniel , Beeman Jeffrey , Bajdich Michael , Higgins Drew , Yano Junko , Drisdell Walter , Davis Ryan , Hahn Christopher , Mehta Apurva , Jaramillo Thomas F.
Published: February 2020

Because of its ability to readily intercalate hydrogen, palladium-based materials are widely studied as hydrogen-selective membranes, hydrogen-storage materials, and catalysts for various hydrogenation reactions. Because the intercalation is reversible, in situ characterization is necessary to understand the physical and chemical properties of palladium hydride. However, most previous studies of palladium hydride focus on a relatively narrow potential range, and the behavior of palladium hydride at more negative potentials relevant to reactions such as CO2 reduction or N2 reduction remains relatively unexplored. Here, we use the combination of synchrotron X-ray diffraction and coulometry measurements to study the absorption of hydrogen into palladium at significantly more negative potentials. X-ray diffraction measurements indicate three phases: palladium, α-PdHx with the lattice expanded by less than one percent, and β-PdHx with the lattice expanded by more than four percent. Concurrent coulometry experiments allow for a quantitative measure of how much hydrogen is stored in palladium in each of these phases. While these two measurements agree quite well near the transition from α-PdHx to β-PdHx, at the most negative potentials we studied, we observe a contraction in the lattice of the film by X-ray diffraction without a corresponding change in the coulometry measurements. This result highlights the need to employ multimodal characterization techniques when studying dynamic phenomena in electrodes, as a single technique may be insufficient to fully elucidate the electrodes’ behavior. Finally, we combine X-ray diffraction with cyclic voltammetry to explore the behavior of palladium hydride with greater time resolution. This measurement reveals clear hysteresis between hydrogen absorption and desorption, emphasizing how the history of the sample affects the degree of hydrogen intercalation. These results provide insight into hydrogen intercalation in palladium electrodes which could lead to improvements in palladium-based materials as electrocatalysts and hydrogen-storage media. Furthermore, this technique can also be applied to study other systems under in situ conditions, such as electrocatalysts for renewable energy transformations.
(Invited) PEFC Electrode Layer Development Via Complementary in Situ Diagnostics and Ex Situ Characterization
Authors: Van Cleve Timothy , Khandavalli Sunil , More Karren L. , Osmieri Luigi , Wang Guanxiong , Star Andrew G. , Kabir Sadia , Cetinbas Firat , Kariuki Nancy N. , Park Jaehyung , Ulsh Michael , Medina Samantha , Mauger Scott A , Pylypenko Svitlana , Myers Deborah J. , Neyerlin K.C.
Published: February 2020

Ink formulation and electrode design optimization is often an iterative process, in which conclusions from in situ performance/ diagnostics as well as ex situ characterization (e.g. microscopy and tomography) are relayed to a model. The model then identifies fundamental limiting phenomena which are to be improved in the next iterative cycle. This process often takes several iterations to ensure an optimal combination of ionic and gas phase accessibility to the active site.

The proper integration of materials to enable high performing low temperature fuel cell operation has never been more crucial to realizing the isolated (e.g. half-cell or ex-situ) improvements of advanced electrocatalysts, supports and ionomers. Variables such as ink formulation (i.e. solvents and solvent ratios), processing method, ionomer chemistry, carbon morphology/porosity and even the presence or absence of Pt, can impact the ink level interactions of the materials set and subsequently alter the final electrode morphology. The resulting electrode structure can in turn influence active site accessibility and ORR activity as well as oxygen transport resistance and electrode proton conductivity.1–5

Here, the development and utilization of in situ diagnostics designed to probe specific phenomena (e.g. catalyst/ionomer interactions, molecular and Knudsen diffusion, electrochemical active site accessibility and catalyst layer proton resistance) will be utilized to contrast the ink, processing and fabrication methods necessary to achieve high performance PGM (e.g. Pt/C and Pt alloy/C) and PGM-free (e.g. FeNx/C) electrocatalysts based electrodes.

References

A. Orfanidi, P. J. Rheinländer, N. Schulte, and H. A. Gasteiger, J. Electrochem. Soc., 165, F1254–F1263 (2018).

S. Khandavalli et al., ACS Appl. Mater. Interfaces, 10, 43610–43622 (2018).

D. Myers, https://www.hydrogen.energy.gov/pdfs/review15/fc106_myers_2015_o.pdf.

F. Xu et al., Langmuir, 26, 19199–19208 (2010).

D. A. Cullen et al., J. Electrochem. Soc., 161, F1111–F1117 (2014).
(Invited) Hard X-Ray Operando transmission X-Ray Microscopy of Electrochemical Systems
Authors: Weker Johanna Nelson
Published: February 2020

Hard X-ray transmission X-ray microscopy (TXM) is an ideal tool for in situ and operando studies of electrochemical systems. The high energy X-rays provides relatively relaxed restrictions on in situ environments enabling high resolution 2D microscopy and tomography (3D microscopy)1 across a large range of pressures and temperatures and in varying gas or liquid environments. The full field geometry of TXM allows imaging at the sub-second time scale, allowing relevant morphological and chemical dynamics to be captured during; for example, battery cycling,2,3 catalysis reactions,4 electrochemical synthesis,5 and corrosion.6,7

This talk will present recent X-ray microscopy results on electrochemical systems studied in situ or operando with a focus on Li-ion and beyond Li-ion battery technologies. In the search for better battery materials, high resolution X-ray microscopy during battery operation is vital in understand and overcoming the failure mechanisms of these materials. Often failures originate as nanometer or sub-nanometer heterogeneities which create a cascade that leads to system failure. TXM can probe the morphological and chemical dynamics of these heterogeneities to understand how and when failure occurs.

N. Weker, N. Liu, S. Misra, J. C. Andrews, Y. Cui and M. F. Toney, Energy Environ. Sci.
2014, 7, 2771-2777.

Nelson Weker, Y. Li, R. Shanmugam, W. Lai and W. C. Chueh, ChemElectroChem
2015, 2, 1576-1581.

Nelson Weker, A. M. Wise, K. Lim, B. Shyam and M. F. Toney, Electrochim. Acta
2017, 247, 977-982.

D. Gonzalez-Jimenez, K. Cats, T. Davidian, M. Ruitenbeek, F. Meirer, Y. Liu, J. Nelson, J. C. Andrews, P. Pianetta, F. M. F. de Groot and B. M. Weckhuysen, Angew. Chem. Int. Ed.
2012, 51, 11986-11990.

E. R. Tay, A. E. Goode, J. Nelson Weker, A. A. Cruickshank, S. Heutz, A. E. Porter, M. P. Ryan and M. F. Toney, Nanoscale
2016, 8, 1849-1853.

A. Koronfel, A. E. Goode, J. Nelson Weker, S. E. R. Tay, C. A. Stitt, T. A. Simoes, J. F. W. Mosselmans, P. Quinn, R. Brydson, A. Hart, Michael F. Toney, A. E. Porter and M. P. Ryan,
npj Mater. Degrad.
2018, 2, 8.

A. Koronfel, A. E. Goode, M. A. Gomez-Gonzalez, J. Nelson Weker, T. A. Simoes, R. Brydson, P. Quinn, Michael F. Toney, A. Hart, A. E. Porter and M. P. Ryan, accepted to
J. Phys. Chem. C.
2019.
Quantifying Concentration Distribution in an Organic Redox Flow Battery Using in-Plane Neutron Radiography
Authors: Forner-Cuenca Antoni , Greco Katharine Virginia , Kowalski Jeffrey A , Boillat Pierre , Brushett Fikile R.
Published: February 2020

Redox flow batteries (RFBs) are promising rechargeable electrochemical devices for grid-scale energy storage, but further cost reductions are needed for ubiquitous adoption of this technology [1]. While recent research trends have focused on molecular discovery [2], advances in the science and engineering of electrochemical reactors can lead to cost reductions via increased power density and/or decreased component cost. Key to such efforts is deconvolution of coupled transport and kinetic processes within operating device and, to this end, imaging diagnostics, such as X-ray tomographic microscopy [3], infrared thermography [4], and electrochemiluminescence imaging [5], have been employed to visualize relevant properties (e.g., fluid distribution, temperature) in RFBs. However, obtaining quantitative property descriptions at high resolution and under representative operation conditions remains a challenge.

In this presentation, we introduce neutron radiography as an operando characterization method for RFBs which is particularly sensitivity to organic materials with high hydrogen content. To demonstrate the potential of this diagnostic tool, we characterize active species concentration distribution within a redox flow cell in a single electrolyte configuration with a nonaqueous electrolyte containing TEMPO/TEMPO+. We use subtractive neutron imaging [6] in combination with isotropic labelling to deconvolute the concentration of different electrolyte materials (i.e. supporting salts, active species). To resolve the concentration profiles across the different layers, we employ the in-plane imaging configuration [7] and correlate these profiles to cell performance via polarization and electrochemical impedance spectroscopy.

References

Darling et al., Energy & Environmental
Science, 7, 3459 (2014).

A. Kowalski et al., Current Opinion in Chemical Engineering, 13, 45 (2016).

Tariq et al., Sustainable Energy & Fuels, 2, 2068 (2018).

Tanaka et al., Journal of Energy Storage, 19, 67 (2018).

Rubio-Garcia et al., Electrochemistry Communications, 93, 128 (2018).

Boillat et al., Journal of The Electrochemical Society, 162(6), F531 (2015).

Boillat et al., Electrochemistry Communications, 10(4), 546 (2008).

Acknowledgments

We gratefully acknowledge the financial support of the Swiss National Science Foundation (P2EZP2_172183) and the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the United States Department of Energy.
Electrochemistry Education for an Undergraduate Audience
Authors: Suroviec Alice H.
Published: February 2020

In this presentation a discussion of current topics related to teaching electrochemistry to undergraduates will be presented. Methods used to teach electrochemical topics to at the sophomore and junior level with differing academic backgrounds will be covered. In addition teaching labs that introduce cyclic voltammetry and reductive desorption will be described. Another lab that has a lot of student interest is how to build a basic biosensor for the detection of common analyses. Teaching electrochemistry is vital at the undergraduate level to get students excited about a seemingly vague area of chemistry. This presentation will hopefully provide new ideas of how to get students engaged in this area of study.
What Your Students Ought to Know about Electrochemistry (But Ask Us Instead)
Authors: Spinner Neil , Paschkewitz Timothy , Peroff Alex , Sun Li
Published: February 2020

“Have you made sure your reference electrode is connected to your potentiostat? Are you even using a reference electrode?”

Electrochemistry equipment manufacturers frequently find themselves in the position where they are providing guidance and troubleshooting advice to graduate students and industry technicians. In addition to these expected services, the role we find ourselves often playing is auxiliary academic advisor. Over the years, our electrochemists have collected numerous anecdotes about a variety of apparent research catastrophes, and graduate advisors may be personally surprised to learn the kinds of stories we have heard. While there are certainly instances when reported problems are valid and require in-depth technical assistance with the instrument, it is not uncommon for the problem to be traced to a gap in fundamental or practical electrochemical knowledge.

When an issue is encountered in an electrochemical experiment, the underlying problem is either the fault of the chemistry or the instrument. This creates tension between the student or technician and the electrochemical equipment manufacturer, and we find that blame is often reflexively passed onto us during a phone call or email exchange. However, the simplicity, and sometimes unintentional comedy, of many of these issues may suggest the heart of the problem is fear of asking one’s advisor, or of damaging equipment from improper use.

In this presentation, we will share some of the recurring problems we encounter from bewildered students and technicians across the world, and use these stories to alert lab directors about some common deficiencies we have observed. While we are sympathetic to the varying methods, busy schedules, and tight deadlines of the average academic advisor (or industry supervisor), our experience of repeatedly filling in basic knowledge gaps suggests there may some simple, practical steps that can be taken with those who are beginning electrochemical research to build a strong foundation for future success.
Electrochemical Tutorials on Diffusion: Models and Demonstrations with Physical Therapy Putty
Authors: Parr Daniel Lee , Leddy Johna
Published: February 2020

Although diffusion is a pervasive concept in chemistry, minimal discussion in chemical education literature provides intuitive explanation of diffusion and mass transport. Explanation of diffusion is often given as a dichotomy: (1) a drunken sailor described by a discrete binomial distribution and (2) a continuous solution of the diffusion (heat) equation. As the dichotomy suggests, there is a persistent dislocation between the drunken sailor and error functions as the two explanations do not align to provide a unified and intuitive explanation of this important and fundamental concept.

Here, we present an introduction to diffusion through models and demonstrations to bridge the intuition gap of diffusion in the classroom. Discrete diffusion is explained initially with the classic drunken sailor narrative and also by the Galton board (Figure 1). The Galton board provides a much improved and intuitive explanation of discrete diffusion via hands-on demonstration of the binomial probabilities.

Transition into continuous diffusion evolves from an explanation of flux (Figure 2.) and concentration gradients, the drivers of diffusion. Finally, we provide a demonstration suitable for any classroom with diffusion of physical therapy putty. The broadening of a physical therapy putty disk with time is modeled with the diffusion equation. Time dependence of the putty radius is observed and compared with the standard diffusion length metric.

Figure 1
(Invited) On Teaching Electrochemical Impedance Spectroscopy
Authors: Orazem Mark E , Tribollet Bernard
Published: February 2020

Impedance spectroscopy is a popular electrochemical measurement technique, but successful implementation requires specialized training that is not easily available. At the 2013 ISE annual meeting in Querétaro, we described our philosophy for teaching electrochemical impedance spectroscopy, embodied in our textbook on the subject, published in 2008 [1]. At the 2017 ISE annual meeting in Providence, we updated our discussion, with emphasis on the second edition of our book [2]. The object of this presentation is to describe our current approach to the subject, reflected in our textbooks on the subject and in our new project, to which we have assigned the working title of The EIS Companion: A Compendium of Solved Problems and Resources.

This communication will describe an approach towards teaching impedance spectroscopy in which students are encouraged to modify experimental parameters in accordance with the experimental system, to use a variety of graphical representations to develop preliminary estimates for physical properties, to develop models from proposed chemical, electrochemical, and physical mechanisms, and to perform regression analyses which account for the error structure of the measurement. As impedance spectroscopy is not a “stand-alone” technique, students are encouraged to seek independent observations that can be used to support or disprove the models developed.

This approach will be illustrated by a step-by-step analysis of a sample data set, including preliminary graphical inspection of the data, evaluation of consistency with the Kramers-Kronig relations, development of an interpretation or process model, regression of the model to the Kramers-Kronig-consistent portion of the spectrum, and evaluation of the physical meaning of the parameters extracted.

M.E. Orazem, B. Tribollet, Electrochemical Impedance Spectroscopy, John Wiley & Sons, Hoboken, New Jersey, 2008.

M.E. Orazem, B. Tribollet, Electrochemical Impedance Spectroscopy, 2nd Edition, John Wiley & Sons, Hoboken, New Jersey, 2017.
Graduate Education in Electrochemistry and Corrosion Science at the University of Virginia
Authors: Kelly Robert G. , Scully John R. , Opila Elizabeth J. , Zangari Giovanni , Koenig Gary , Burns James T.
Published: February 2020

The goals and methodology of graduate education in corrosion science and engineering at the Center for Electrochemical Science and Engineering at The University of Virginia are reviewed. These include establishment of both core competencies and advanced understanding(s) in materials science, electrochemistry applied to corrosive degradation in aqueous solutions, surface science and engineering, solution chemistry and/or fracture mechanics through a plan of study typically involving 13 graduate classes in Engineering, Chemistry and/or Physics. In addition a key aspect of our educational goal, beyond the classroom, is a significant and in-depth Master of Science and Doctor of Philosophy research experience culminating in a written thesis or dissertation and oral defense. This research experience is designed to provide an excellent training ground for development of individuals capable of not only performing multi-disciplinary research in the corrosion field, but also with the capability of surveying the literature, identifying research gaps and opportunities and developing strategies for addressing such needs. Corrosion science and engineering students perform focused research in the areas of aqueous corrosion, high temperature corrosion, environmentally assisted cracking. Interactions with other faculty and students providing education and performing research in other electrochemical technical areas (e.g., electrodeposition, photoelectrochemistry, batteries) provide critical enhancements to the students’ experience. At the end of this experience, students are capable of either performing as competent corrosion engineers or as scientist making both technological and scientific contributions to our field with good written and oral communication skills. The course curricula, research philosophies and the assessments used to achieve these goals are presented.
Stress and Mental Health in Chemistry Graduate Education
Authors: Anderson Evan L , Mousavi Maral PS , Lust Katherine , Buhlmann Philippe
Published: February 2020

A key challenge for any graduate program is to address stress and mental health without lowering the bar for the degree. In our department, we have focused on eliminating unnecessary sources of stress. We, that means not just the departmental leadership, but graduate students, the director of graduate studies, mental health advocates, and professionals from the university health services. Only professionals can provide therapy, but the whole community can contribute to help prevent problems before they arise and to recognize and direct students in distress to appropriate resources. In particular, the student group Community of Chemistry Graduate Students (CCGS) is taking a key role in organizing regular events on physical and mental health and stress management. For example, their videos on the topics of mental health in graduate school, academic success, and the transition into a job after graduate school have attracted much attention. A very important tool to help us in our efforts is a biannual survey specifically designed together with the university health services to assess the sources of stress. This talk will address some of the new insights we have gained from analyzing the results of these surveys.

(1) Stress and mental health in graduate school: How student empowerment creates lasting change, Mousavi, M. P. S.; Sohrabpour, Z.; Anderson, E. L.; Stemig-Vindedahl, A.; Golden, D.; Christenson, G.; Lust, K.; Bühlmann, P. J. Chem. Ed.
2018
, 95, 1939–1946.

(2) http://ccgs.chem.umn.edu/surviving-and-thriving-higher-education
Rethinking Electrochemical Science and Engineering Education
Authors: Garzon Fernando H , Tsui Lok-kun , Svihla Vanessa , Datye Abhaya
Published: February 2020

Electrochemical Science and Engineering is a particularly challenging subject to teach at the undergraduate/graduate level. The students need a substantial background in the physics of electrostatics, fields, potentials, and electrical circuits, solution chemistry, thermodynamics, mass transport and kinetics. They must also be versed in the underlying mathematics of differential and integral calculus. A lack of knowledge or retention of any of the aforementioned prerequisite subject areas can pose significant barriers to advanced learning. A minority of the students at The University of New Mexico have had some prior training in electrochemical research from internships at UNM, and National and Defense laboratories. The performance of the student interns was largely superior to the students with no direct laboratory experience. These students were generally much more engaged at achieving a better understanding of the underlying science behind their laboratory work. A major goal of the School of Engineering at UNM is to improve the comprehension and retention of key fundamental concepts and skills in the aforementioned areas for all students in the chemical engineering field and provide more opportunities for “hands on” learning and skills development.

The Department of Chemical and Biological Engineering (CBE) at the University of New Mexico is engaged in a program to revolutionize engineering education by launching FACETS: Formation of Accomplished Chemical Engineers for Transforming Society. FACETS will revolutionize CBE by: (1) introducing "CIRE" design challenges in the core curriculum that are Community-, Industry-, Research-, and/or Entrepreneurship-based; (2) conducting professional development institutes that will train and mentor faculty and graduate students; workshops will be led by experts from industry and national laboratories, from the learning sciences, from engineering education and multicultural studies, for example the directors of UNM Native American Studies and Chicano/a Studies, and (3) create a digital badging system that will help students take ownership of their competencies and develop engineering identities and enable faculty to monitor and assess student outcomes and to engage in research on their teaching. We believe that this comprehensive approach towards modular learning and digital validation will improve our teaching of Electrochemistry and Electrochemical Engineering and heighten our student’s understanding of the subject material. We have prepared core concept modules with supporting experimentation in the subject areas of: Types of Electrochemical Cells, Solution Theory, Electrostatics, Electrolytes, Ionic Transport, Charged Interfaces, Electrochemical Thermodynamics, Batteries, Fuel Cells, Electrolysis, Electrodeposition, Electroanalysis and Environmental Electrochemistry.
Integrating Hands-on Battery Design into a Chemical Engineering Unit Operations Laboratory
Authors: Mustain William E.
Published: February 2020

Though electrochemistry and electrochemical engineering play significant roles in the behavior of many engineered systems – either through their fundamental operation (i.e. batteries) or secondary effects (i.e. corrosion) – engineering undergraduates typically do not graduate with appreciable fundamental knowledge in these area. It is important for our community to reach out to these students and develop coursework modules that build both fundamental and applied knowledge related to electrochemical systems. In this talk, integration of electrochemical science and engineering principles into a Junior Laboratory course will be discussed. The battery module in this course was offered for over a two-year period.

In this laboratory, teams of four students are provided with a problem statement: Design a battery pack that can seamlessly REPLACE the AA batteries in a child’s toy. Students are allowed to choose their own platform. They must determine the power requirements for the toy under various operational conditions. Of course, on day 1, undergraduates do not know almost anything about how to design a battery. Therefore, the students systematically step them through a series of tasks and lectures to build their knowledge and competency – covering thermodynamics, polarization (kinetics and mass transfer), cell design, etc. These lectures and iteration of their battery design occurs over the course of an entire semester. The details around these will be discussed in the talk.

The lab culminates with a demonstration day where teams show off their home-made batteries, operating a wide range of toys.
Electrochemical Behavior of Redox Active Organic Molecules in Ethaline Deep Eutectic Solvent
Authors: Squire Henry John , Klein Jeffrey Michael , Gurkan Burcu
Published: February 2020

Deep eutectic solvents (DES) are a relatively new class of electrolytes with potential application in electrochemical systems. DES are mixtures of hydrogen bond acceptors (HBA) and hydrogen bond donors (HBD) that engage in a unique hydrogen-bonding network. Like traditional organic solvents, DES have the advantage of a wide electrochemical window compared to aqueous electrolytes, but with additional advantages over organic solvents such as low volatility and high energy density due to solvation strength towards redox active species. DES have shown promise for application in redox flow battery systems currently limited by lack of nonvolatile, high energy density electrolytes. While DES offer a potential solution to these issues, high viscosity and low conductivity have thus far limited their practical application. Catechol and 1,4-benzoquinone were introduced as redox active species and hydrogen bond disruptors to ethaline DES which is a 1:2 molar mixture of choline chloride and ethylene glycol. These redox active organic molecules are of particular interest due to their high solubility in DES. Furthermore, the reduction mechanism of these molecules does not involve electrodeposition and subsequent electrode morphology changes. This addresses issues often associated with traditional redox active species such as metal halides used in redox flow batteries.

The physical and electrochemical properties of ethaline with catechol and 1,4-benzoquinone were investigated. Effects of the DES hydrogen-bonding network on the redox potentials, electrochemical reversibility, and diffusivity was investigated by voltammetry. Temperature dependent viscosity, conductivity, and density were measured to investigate the impact of hydrogen bond disruptors on macroscopic properties. Finally, attenuated total reflectance infrared spectroscopy was used to investigate the molecular interactions between the redox active species and the hydrogen-bonding network in DES to relate observed macroscopic properties to molecular level features. This work provides insight into the solvation of organic redox active species in DES and its impact on physical and electrochemical properties.
Thin Layer Sonoelectrochemistry: Electrocatalysis in Oxygen Reduction Reaction (ORR) and Methanol Electrolysis
Authors: Duda Chester G , Leddy Johna
Published: February 2020

In electrochemical energy systems such as fuel cells, important reactions include the oxygen reduction reaction (ORR) and methanol oxidation. Even with platinum catalysts, oxygen reduction kinetics in water at acidic pH are slow. In H₂ proton exchange membrane fuel cells (PEM FCs), ORR is the rate determining kinetic process. In direct reformation fuel cells run on methanol with an oxygen or air cathode, methanol oxidation kinetics are rate limiting. Limitations include slow electron transfer processes coupled to generation of oxidation by-products that adsorb to the electrode and lead to passivation.

Sonoelectrochemistry in thin layers of electrolyte enhances electrochemical rates without visible cavitation using low power oscillators [1]. Here, thin layer sonoelectrochemistry coupled with cyclic voltammetry is used to evaluate impacts of sonication in a thin layer on the electrochemical response of oxygen and methanol .

For voltammetry at platinum electrodes for saturated oxygen in acidic aqueous electrolyte, the rate of the ORR is enhanced several orders of magnitude as shown by fit of the cyclic voltammetric data.

For stoichiometric (50:50) methanol in water with acid electrolyte, oxidation and reduction currents at platinum electrodes are increased almost ten fold as shown in cyclic voltammetric responses. Sonication may increase the rates of electron transfer and remove deposited partial oxidation products.

Improved kinetics of oxygen reduction and methanol electrolysis may provide a means to improved electrochemical energy technologies, including hydrogen and direct reformation fuel cells. The energy needed to drive the oscillator represents a low parasitic loss on fuel cell performance.

Reference

[1] Johna Leddy, Chester G. Duda, Jacob Lyon, and William J. Leddy III, "Thin Layer Sonoelectrochemistry and Sonoelectrochemistry Devices and Methods," published 28 May 2015 as US Patent Application 20150147594 A1.
Pulsed Electrodeposition of Trivalent Chromium Under Ultrasonic Conditions
Authors: Hall Timothy D. , Radhakrishnan Rajeswaran , Rauch Jeanne-Marie , Lallemand Severine , Gigandet Marie-Pierre , Rolet Jason , Merlet Johann , Hihn Jean-Yves , Tardelli Joffrey , Inman Maria , Taylor E. J.
Published: February 2020

In part of a joint collaboration effort between Faraday Technology Inc., the UTINAM Institut (Besançon France), and the IRT M2P consortium in France we have been evaluating the potential of sono-electrochemical system within a state of the art REACH compliant trivalent hard chromium electrolyte. The need for a trivalent hard chromium electrolyte is based on the requirement of the industry to identify a suitable carcinogen free alternative to hard hexavalent chromium electroplating. Through our collaborative activity we have demonstrated the potential of this electrolyte to produce coatings with equivalent or superior: 1) plating rate, 2) Knoop hardness, 3) current efficiency, 4) adhesion, 5) corrosion resistance, 6) thickness, 7) Taber Abrasion, Ball on Flat Reciprocating and Dithering wear resistance, and with no hexavalent chromium formation in the bath. Moreover, ultrasound have proven to be an efficient process in improving penetrating capacity of the Cr coating into complex shapes. Furthermore, we have identified a potential process enhancement by utilizing sono in conjunction with pulse electrodeposition to improve wear index and achieve through into the recesses of type 1A1 embrittlement bars.

Acknowledgements: This study is supported by the US Army (W911NF-11-2-0014) and private sources, and by HCTC project
(Invited) From Intercalation/Insertion to Conversion Mechanism; Efforts for Increasing Energy
Authors: Sakaebe Hikari
Published: February 2020

Development of high energy batteries has been aspired all over the world to expand the usage in vehicles. Performance of Li-ion batteries (LIB) has been continuously improved since launched on the market. Quite recently a high energy battery pack over 300 Wh/kg was reported. A history from Li secondary battery to LIB tells us the merit of electrode materials with intercalation/insertion mechanism for sufficient life of the battery.

We may have to discuss about how much energy is actually required, but higher the energy density, more variety of the balance between each performance could be realized. Design of the systems would be easier if we could withdraw the theoretical restriction of LIB. Now conversion type electrodes attract much attention.

　Author’s group has developed the technique to increase energy of positive electrode for LIB, by surface modification and analogue of Li-excess layered materials. The latter seems closely related to the conversion mechanism. Then we focus on metal polysulfides such as TiS4 and Li5FeS8 with specific capacity of more than 700 mAh/g by an intermediate mechanism between insertion and conversion [1, 2]. FeF3 related positive electrodes show maximum energy density as closed system, and are operated by full conversion reaction to 3LiF + Fe for this purpose. This is more challenging and several technical barriers should be cleared. We hope to understand how to balance the energy density and other important properties through the materials we developed.

References

[1] A. Sakuda, H. Sakaebe, T. Takeuchi, et al., J. Am. Chem. Soc., 139, 8796 (2017) .

[2] T. Takeuchi, H, Sakaebe, et al., Solid State Ionics, 320, 378 (2018).

Acknowledgement

This work was supported by the New Energy and Industrial Technology Development Organization (NEDO) under the “Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2)”
Extending Cycle Life and Safety of Si Based High Energy Li Ion Batteries Using Localized High Concentration Electrolytes
Authors: Zhang Ji-Guang , Jia Haiping , Li Xiaolin , Cao Xia , Yi Ran , Li Qiuyan , Xu Wu
Published: February 2020

Si is one of the most promising anode materials for the next generation of lithium (Li) ion batteries (LIBs). Although various forms of nano Si and Si/C composite have been designed to minimize pulverization of Si, the stability of Si/C based anode is still limited by many other factors, especially the selection of electrolytes. Recently, we have developed localized high concentration electrolytes (LHCE) for Si based anode. It is found that the optimization of electrolytes for Si/C composite anode not only depends on the stability of electrolyte against Si, but also depends on the stability of electrolyte against binder and graphite used in the Si/C composite. Electrolyte additives also play an important role in the long-term stability of the Si based anode. In addition, electrolyte also need to be stable at high voltage conditions to enable high energy LIBs. This work will discuss various factors that affect the stability and safety of Si based LIBs and demonstrate highly stable electrolytes that lead to long term stability of silicon based high energy LIBs using commercial Si nano powder and graphite. The future directions on Si based LIBs will also be discussed.
Simulated Crystal Growth of Intermediate Phases Formed during Li and O Extraction of Nano-Li2MnO3 Cathode Material
Authors: Malibe Tshidi , Ledwaba Raesibe Sylvia , Matshaba Malili G , Ngoepe Phuti E
Published: February 2020

Li2MnO3 is considered as a potential candidate for high capacity (theoretical capacity of 458 mAh/g) lithium ion batteries applicable in electric vehicles owing to its larger number of exploitable Li ions. However, it is vulnerable to degradation originating from complex phenomena such as the oxygen release, phase transformation and Li+ /H+ exchange reaction, but the detailed mechanisms governing these degradation behaviors have not been fully understood yet. In the current work, spontaneous crystal growth of the nano-Li2MnO3 structures via the amorphisation and crystallisation technique is carried out with systematic removal of oxygen and lithium contents in a quest to explore the formation of different intermediate structures/phases. The simulated nano-architectures crystallised into multi-grained (except for Li1.75MnO2.75) and highly defective structures. To study the formation possible phases, the XRD patterns were measured for all intermediate structures and reveal emergence of new Mn3O4 peak at 2Ө~ 29⁰ and strong cubic spinel LiMn2O4 at 2Ө~ 37⁰. Microstructural analysis revealed the formation of layered and spinel-type structures for low lithium and oxygen content nanostructures. These findings shed light towards mechanisms that take place during the cycling of nanostructured high capacity oxide electrodes during lithium and oxygen extraction that will help guide the optimisation of new Li-rich materials for rechargeable lithium batteries.
Thermodynamic Origin of Reaction Inhomogeneity in Thick Battery Electrodes
Authors: Wang Fan , Tang Ming
Published: February 2020

As battery electrodes continue to be made thicker to improve energy density at the cell level, reaction non-uniformity within the electrodes during charge/discharge becomes increasingly severe, which degrades rate performance and increases the risk of overcharge / overdischarge. A thorough understanding of the origins of such phenomenon is important for developing its mitigation strategies. Prediction of reaction inhomogeneity in battery cells traditionally relies on numerical simulations based on the Newman-type model. Here we present an alternative approach using “reduced-order” theoretical models, which allow for faster and yet reliable predictions and also provide a more transparent understanding on the dependence of reaction non-uniformity on material properties, cell geometry and (dis)charge conditions. An analytical mass transport model is developed to predict reaction distribution and discharge performance in thick electrode systems that are kinetically limited by electrolytic transport. A circuit model is further proposed to analyze the interplay between surface reaction, electronic conduction and electrolytic transport in controlling the degree of reaction non-uniformity. One significant insight from this study is that inhomogeneous reaction is not only kinetically induced but also influenced by the intrinsic thermodynamic properties of the electrode materials, specifically their SOC dependence of the equilibrium potential. Electrodes that undergo first-order phase transitions upon cycling and exhibit a flat voltage curve against SOC, such as LiFePO4 and Li4Ti5O12, produce “move-zone” reaction behavior with strongly non-uniform Li intercalation flux. In contrast, battery compounds with sloped voltage curves such as layered transition metal oxides inherently favor uniform reaction within electrodes. Counter-intuitively, our theoretical model and numerical simulation suggest reducing the electronic conductivity and surface reaction kinetics as an effective strategy to improve the reaction uniformity in thick electrodes.
A Deposition Comparison of Gold Particles Modified Boron Doped Diamond Electrodes for Nitrite Sensing
Authors: Cai Xiaosheng , Foord John S.
Published: February 2020

This work compares pulse and cyclic voltammetry deposition of Au particles on boron doped diamond electrodes for determination of nitrite. Gold particles of different sizes from nanometer to submicron with different morphologies from sphere to star shape are obtained using different deposit parameters for optimization of nitrite detection. The nitrite sensing experiments via the amperometry method show that a better limit of detection for gold particles decorated by the pulse deposition, thus demonstrating a benefit of using this method for electroanalysis.
Electrochemical Behavior of Citrate Cu-Zn Electrolytes for Copper Alloys Electrodeposition
Authors: Dridi Amina , Dhouibi Leila , Hihn Jean-Yves , Bercot Patrice , Rezrazi El-Mustafa , Sassi Wafa
Published: February 2020

Brass coating is ordinary produced by a successive deposition of zinc and copper, followed by a thermal diffusion step, despite its high energy consumption[1]. Direct alloy electroplating is difficult, because of the difference in reduction potentials of zinc and copper which is over than 1 V, making commercial non-cyanide baths not available. To allows a simultaneous deposition of those two cations on the cathode surface, the difference between their reduction potentials must be decreased to a value lower than 200 mV [2], by the addition of complexing agents. An experimental and theoretical study of the influence of complexing agent on the electroplating process of brass was conducted. To this end, a simulation of the chelates distribution as a function of pH and ligand concentration was done using Scilabâ software. Then, optimal speciation conditions in regards of bath stability were chosen, and the obtained aqueous citrate electrolytes were characterized by UV–VIS spectrophotometry, copper in and studies of current polarization curves for copper–zinc deposition. It appears that a 1:10 copper to citrate ratio is the most promising electrolyte. Linear sweep voltammetry presents peaks reduction for copper and zinc as well as for codeposition conditions. From this curves, various deposition potential have been chosen, and a same charge quantity was used to elaborate corresponding deposits. The latter will be quantify by anodic dissolution, giving the reaction Faradic yield.Finally, the technical feasibility of plating was made, and the possibility to control the alloy element content was checked using Hull Cell plating test. It appears that current density as well as zinc concentration are the main parameters to govern the alloy composition and properties.

[1] Q. WANG, W. DU, L. LI, X. LÜ, S. ZHANG, The effect of ionic liquid additives on the electroplating brass from non-cyanide bath, Chinese Sci. Bull. (Chinese Version). 60 (2015) 2553. doi:10.1360/N972015-00317.

[2] C. Meudre, L. Ricq, J.-Y. Hihn, V. Moutarlier, A. Monnin, O. Heintz, Adsorption of gelatin during electrodeposition of copper and tin–copper alloys from acid sulfate electrolyte, Surf. Coatings Technol. 252 (2014) 93–101. doi:10.1016/J.SURFCOAT.2014.04.050.

[3] A. Dridi, L. Dhouibi, J.Y. Hihn, P. Berçot, W. Sassi, M. Rezrazi, Study of the influence of complexes stability on the kinetic of CuZn electroplating in a citrate bath, Submitted Electrochim. Acta.

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Improved Performance of Zinc Composite//Secondary Doped Li-PANI Composite Film for Rechargeable Batteries
Authors: Cao Huijun , Si Shihui
Published: February 2020

To improve the conductivity of pure polyaniline (PANI), compact scale-like PANI secondary doped with lithium chloride (Li-PANI) was prepared after the in-situ synthesis of PANI powder using the constant current method and 4,4’-diaminobiphenyl (DABP) as an additive in hydrochloric acid (HCl) solution. The compact morphology of obtained Li-PANI was feasible for improvement the charge transfer in the PANI chains and inter-molecular. The oxidation peak currents of Li-PANI with DABP additive were nearly three times higher than those of the Li-PANI and much higher than those of in-situ doped PANI in only HCl solution. Both the LiCl-PANI/TiO2/C/DABP composite ( Li-PANI composite) and Zn/ZnO/MgO/CMC-Na composite (Zn composite) were prepared by homogeneously coating at controlled thicknesses (0.20 mm and 0.04 mm, respectively). A Zn composite was used as cathode and Li-PANI composite as anode for the fabrication of improved Zn//PANI battery, with an open voltage of approximately 1.5 V in ZnCl2+LiCl electrolyte solution. The battery charge/discharge cycle performance was determined between 0.7 V and 1.7 V. The discharge capacity of the cathode reached 131.4 mAh·g-1 at a current density of 2 mA·cm-2. During 35 charge/discharge cycles, the average decrease in the discharge capacity of each cycle was 0.07%, indicating that the cycle performance and stability of the designed battery revealed the feasible competition potential with traditional batteries.
(Invited) Thiophosphate Based Solid Electrolytes and Cathodes Interfaces
Authors: Nanda Jagjit , Self Ethan Craig , Delnick Frank M.
Published: February 2020

Stable high ion-conducting solid electrolytes are enablers for all solid state batteries. Among many class of materials, Lithium thiophosphate family of solid electrolytes have been investigated for their (a) superionic ion-conductivity (>10-4 S/cm), (b) mechanical softness and higher interfacial wettablity, (c) relatively simple synthesis and processing routes and (d) lower cost and earth abundance. Despite such advantages thiophosphates are known to have a narrow electrochemical stability window with a thermodynamical stability window between 1.7-2.6V (with respect to Li+/Li). Under such scenario, interfacial stability between Lithium thiophosphate/Li-metal and cathodes are primarily dictated by kinetic control by formation of a reaction passivation layer. Interfacial charge transfer depends on the detailed composition of the passivation reaction at the interface. The talk will highlight on the electrochemical performance characterization of the solid electrolyte, Li3PS4 and lithium-ion cathode such as LiFePO4. Detailed interfacial characterization between Li3PS4 and cathode interphases probed by XPS, NMR and electrochemical impedance spectroscopy (EIS) will be presented. In addition, synthesis and characterization of high capacity polysulfidophosphate cathodes based on catenation of sulfur to thiophosphate electrolytes, Li3(PS4)Sn where n = 5,8,6,3,2 will be discussed.
High Efficient Ion Selective Membrane Separator for Room Temperature Sodium Polysulfide Redox Flow Batteries
Authors: Amiri Azadeh , Wang Tongshuai , Bae Chulsung , Kim Sangil
Published: February 2020

Redox flow batteries (RFBs) have attracted extensive attention in recent years due to their low cost, safe operation, and design flexibility for large scale energy storage applications. Among all the RFBs, room temperature sodium (Na) polysulfides (PS) RFBs are the most promising because of the abundance and low cost of Na compared to Li. However, both Na-S battery and Na-PS flow batteries suffer from polysulfide diffusion between their two working electrodes which decreases the batteries’ columbic efficiency and shortens their cycle stabilities. This shuttling issue is more detrimental in the case of Na-PS RFBs which doesn’t have carbon matrix to immobilize the solid-state sulfur. Unfortunately, commercial battery separators (e.g. Celgard) cannot be adopted because those membranes are freely permeable to the polysulfide ions. Alternatively, ion selective membranes (e.g. Nafion), which have been employed in aqueous redox flow batteries, have been explored to prevent the polysulfide, however, they also showed poor performances in organic RFBs because of swellings in organic electrolytes and low lithium ion selectivity over polysulfide ions.

Here we present a biphenyl backbone-based aromatic hydrocarbon membrane with high sodium conductivity as well as sodium selectivity over polysulfides. The conductivity and sodium-polysulfide (Na2S6) diffusivity of sodiated membrane was measured and compared with Nafion membranes. The Na-PS diffusivity of our IEM (3.17×10-11 cm2/sec) is two order magnitudes lower than that of Nafion (1.02×10-9 cm2/sec), while it showed high Na ion conductivity (3.27×10-5 S/cm) comparable to Nafion (3.37×10-5 S/cm). Thus, Na/PS selectivity of the BP-SA is significantly higher than Nafion. We will discuss the high performance of sodium-polysulfide redox flow battery with the BP-SA membrane and compare its efficiencies with the cell with Celgard2325 and Nafion.