bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Situ Spectrospecopy Investigation of the Surface-Interface Charge-Transfer Process over Tailored Nano-Structured Based PEC Fuel Cells for Solar Energy Harvesting and Conversions
Authors: Li Xinyong 
Published: February 2020

Solar energy induced catalytic reactions allow solar energy to be used directly in sunlight-to-chemical energy conversions. Many scientific progress have been made in solar energy utilization and conversions, whereas, scientists from all over the world claimed that there are still many problems need to be further addressed including how to further enhance the solar energy utilization & conversion efficiency etc. The detail micro-interface process, redox mechanism, charge-carrier transfer behavior and active species actions need to be further studied. Following all of these concerns, series of multifunctional complex oxides with hetero-junctions have been well designed in our group towards solar energy utilization and conversion process via photo-induced chemical process, and different transient physical techniques including in situ EPR, in situ SPV and transient laser flash photolysis etc. have also been used to elucidate the interfacial photo-induced redox process and charge-carrier behaviors.
We found that hierarchical nanostructured assemblies can be engineered to tailor the properties of external fields modulated and/or light harvesting assemblies. The crystal-, micro- and surface-interface structure could be tailored by utilizing various synthesis strategies, which would incur the nanomaterials with novel PEC/PC properties. Furthermore, combined in
-
situ spectroscopic characterization could provide more detail structural information and redox process over micro-interface, which would be beneficial for design efficient solar and energy conversion based materials at molecular utilization and/or atomic level. The tailored hierarchical nanomaterials may find novel applications in multidisciplinary fields.
Recent Advances with Terpyridine-Based Monolayer Electrochromic Materials
Authors: Easton E. Bradley , Poisson Jade , Laschuk Nadio O , Geoffrey Heather L , Allan Jesse T.S. , Ebralidze Iraklii , Quaranta Simone , Zenkina Olena V , Gaspari Franco 
Published: February 2020

Electrochromic (EC) materials are a class of “smart” materials that change their optical properties in response to an applied potential. This optical change can be the development, loss, or variation in the color of the material. EC materials have recently become a research focus because of their high commercial applicability in “smart” windows, antiglare mirrors, and low-power displays. Most current EC materials are based on thick layers of EC molecules or EC molecules/ conductive polymer blends on the electrodes. The device properties depends strongly on the overall composition and distribution of the EC species in the polymer structure.
We have developed an EC systems that contain as little as a monolayer of the EC molecules deposited onto a surface-enhanced conductive support [1]. The process involves the covalent attachment of various terpyridine-based ligand to the surface of a nanostructured conductive indium − tin oxide (ITO) screen-printed support by a simple submerging of the support into an aqueous solution of L. Subsequent reaction of with metal ions (e.g. Fe, Ru) leads to the formation the monolayer of the redox-active metal complex covalently bound to the ITO support. In addition, isolated and well-defined terpyridine- based metal complexes (Fe, Os,Co) were simply deposited on ITO screen-printed surface via conventional chlorobenzylsiloxane-based template.
Our fabrication approach utilizes the inter-particle porosity of the support and requires as low as a monolayer of EC active molecule, giving significant molecular economy when compared with traditional polymer-based EC devices.
This presentation will feature an overview of our synthetic methods, including how we can alter the color of the films by changing either the metal center of the ligand itself [2]. Spectro-electrochemical studies enabled us to correlation optical density with redox site density. Furthermore, detailed electrochemical studies enabled the determination of the kinetic rate constants for electron transfer for these films [3], which were considerably higher than other approaches in the literature. These novel light-reflective EC materials demonstrate a high color difference, significant durability, fast switching speed, excellent stability and high EC reversibility.

References

[1] J.T.S. Allan, S. Quaranta, Ebralidze, II, J.G. Egan, J. Poisson, N.O. Laschuk, F. Gaspari, E.B. Easton, O.V. Zenkina, ACS Appl Mater Interfaces, 9 (2017) 40438-40445.
[2] N.O. Laschuk, Ebralidze, II, J. Poisson, J.G. Egan, S. Quaranta, J.T.S. Allan, H. Cusden, F. Gaspari, F.Y. Naumkin, E.B. Easton, O.V. Zenkina, ACS Appl Mater Interfaces, 10 (2018) 35334-35343.
[3] J. Poisson, H.L. Geoffrey, I.I. Ebralidze, N.O. Laschuk, J.T.S. Allan, A. Deckert, E.B. Easton, O.V. Zenkina, The Journal of Physical Chemistry C, 122 (2018) 3419-3427.

Figure 1
Hydrogen Evolution Reaction on Transition Metals: Promoting Water Dissociation By Tuning the Surface Oxophilicity.
Authors: Farinazzo Bergamo Dias Martins Pedro , Strmcnik Dusan , Lopes Pietro Papa , Connell Justin G. , Ticianelli Edson A. , Stamenkovic Vojislav R. , Markovic Nenad M. 
Published: February 2020

Hydrogen evolution reaction (HER) has been at the core of the development of fundamentals of electrochemistry and electrocatalysis. In acidic electrolytes, it has been generally accepted that the differences in reaction rates/activity are closely related to the differences in hydrogen adsorption free energy on different materials. In recent years, the fundamental investigation of the HER has been enjoying a renewed vigor, but this time in alkaline electrolytes, where there is much less consensus on the underlying activity descriptors. While some groups insist on the single descriptor of hydrogen binding energy, our group has continuously pointed out to the bifunctional nature of the HER in alkaline environments, i.e. a good catalyst needs both a beneficial OHad energetics and beneficial Had energetics. In most cases, the OHad-metal energetics is by far the more unfavorable of the two and OHad adsorption therefore represents the rate determining step. In some cases (e.g. polycrystalline iridium), the OHad-metal energetics no longer represents a significant obstacle in the HER process; hence the catalyst's rate determining step becomes Had adsorption and the catalyst starts behaving as it would in acid – as a pseudo mono-functional catalyst. For most materials, however, the HER rates in alkaline environments are significantly lower than in acid. One such example is copper (Cu), where reported values for HER activity in alkaline are indeed lower but are interestingly scattered over a wide range of values. In a manuscript recently published [1], we were interested in the underlying cause of these discrepancies. We explore how the different history the polycrystalline copper surfaces experienced changes their electrochemical properties (e.g. the HER activity). By using detailed spectroscopic surface analysis, we were able to find different extents of oxidation on various copper surfaces and link them to different hydrophilicity of the surfaces. With the established trends we propose that the formation of Cu(I)-OHad‐‐‐OH2 activated complex is essential in lowering the energy barrier for water dissociation, which leads to higher activity for the HER in alkali environments.
[1] Farinazzo Bergamo Dias Martins, P. et al. Hydrogen evolution reaction on copper: Promoting water dissociation by tuning the surface oxophilicity. Electrochem. commun.
100, 30-33 (2019).
Modeling the Mesoscopic Influence of SEI Mechanical Response to Electrode Swelling
Authors: Hooper Justin B. 
Published: February 2020

This work focuses on investigating the role that mesoscopic configuration plays in dictating the solid-electrolyte interface (SEI) mechanical durability on lithiation in silicon (Si) anodes. Due to the large expansion of Si upon lithiation, SEI formation and cohesion at the electrolyte interface of Si based anodes is a principle concern in performance of the overall cell, and enabling a more durable SEI would lead to the ability to employ higher Si percentages in anodes, increasing capacity. However, we are still building fundamental understanding of SEI formation and the resultant meso- and microscopic structure evolved due to this formation. This work seeks not to understand the formation itself, but instead to establish intuition about what type of resultant structure we should target as we learn to control the SEI formation process, by investigating the effect that non-homogenous SEI configurations have upon the overall SEI response when subjected to large strain due to the swelling of the underlying Si anode.
Utilizing the material point method (MPM), a continuum mechanics approach akin to the finite element method, but particularly well suited for investigation of materials subjected to large deformation, we model the intrinsic swelling of Silicon under lithiation when coupled to a model SEI. This model SEI, in turn, is constructed of multiple different phases with mesoscopic variability and realistic material response parameterized from atomistic simulation of the mesoscopic phases including both crystalline and glassy inner SEI compounds and ordered/disordered outer SEI compounds derived from liquid carbonate decomposition products. Model mesostructures are constructed and fed into the MPM framework, from which an overall SEI mechanical response may be extracted via numerical simulation. By varying the mesostructures, sensitivity of the mechanical response to the mesostructural features is quantified, providing guidance to possible experimental approaches at improving the SEI capability of protecting the anode during multiple charge/discharge cycles.
Synchrotron-Based Characterization of Perfluorinated Sulfonic-Acid Ionomers
Authors: Dudenas Peter J , Weber Adam Z. , Kusoglu Ahmet 
Published: February 2020

Perfluorinated sulfonic-acid (PFSA) ion-conducting polymers (ionomers) serve as both a binder and active ion-transport material in electrochemical energy-conversion electrodes including fuel cells, electrolyzers, and redox-flow batteries. Within the catalyst layer of these devices, ionomer shuttles ionic and liquid or gaseous species to/from catalytic sites.1-2 Optimizing the multi-functional role that PFSA ionomers play is crucial to developing next generation devices, and, to do so, the underlying fundamental structure-property relationships of these materials must first be established. Reducing the complex heterogeneous environment of catalyst layers down to representative model systems enables probing these relationships in a systematic and fundamental manner. To accomplish this effort, we spin-cast thin films of Nafion and 3M ionomer chemistries, including multi-acid side chains, across a range of thicknesses and processing conditions. Synchrotron-based x-ray scattering and spectroscopy, and advanced analysis of the collected data, is employed to characterize the phase-separated nano-structure of PFSA thin films. Results show the universality of confinement effects across chemistries, and how processing conditions modify the chemistry-confinement interplay and impact structure-function relationships. X-ray characterization is carried out in both ambient and humidified environment, in-situ, to determine the nanostructural changes in ionomer film in response to environment. These structural investigations are correlated to thermodynamic swelling properties using ellipsometry to identify factors controlling ionomer transport functionality in electrode structure of energy conversion devices.
Acknowledgments
We thank Mike Yandrasits and Andrew Haug of 3M for providing ionomers and helpful discussions. This research used beamline 7.3.3 of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.3 The study was funded under the Fuel Cell Performance and Durability Consortium (FC-PAD) funded by the Energy Efficiency and Renewable Energy, Fuel Cell Technologies Office, of the U.S. Department of Energy under contract number DE-AC02- 05CH11231.
References

Mauritz, K. A.; Moore, R. B., State of understanding of Nafion. Chemical reviews
2004,
104 (10), 4535-4586.

Kusoglu, A.; Weber, A. Z., New Insights into Perfluorinated Sulfonic-Acid Ionomers. Chemical Reviews
2017,
117 (3), 987-1104.

Alexander, H.; Wim, B.; James, G.; Eric, S.; Eliot, G.; Rick, K.; Alastair, M.; Matthew, C.; Bruce, R.; Howard, P., A SAXS/WAXS/GISAXS Beamline with Multilayer Monochromator. Journal of Physics: Conference Series
2010,
247 (1), 012007.
(Invited) Successes and Challenges of Teaching and Conducting Electrochemistry-Based Research at an Undergraduate Institution
Authors: Kariuki James 
Published: February 2020

Undergraduate research, which is considered a high-impact practice in higher education, has been shown to provide an enriching educational experience to students. Undergraduate research provides students with an opportunity to engage in hands-on activities and allows them to develop potential solutions to real-world problems. It has been demonstrated that students who participate in undergraduate research significantly improve their critical thinking and communication skills and are more satisfied with their overall educational experience.
My presentation will focus on recruitment strategies for undergraduate researchers, different categories of research projects, and the successes and challenges associated with undergraduate research. Specifically, my talk will focus on the teaching of electrochemistry and discuss the scope of possible electrochemistry-based research at a primarily undergraduate institution.
Deconvoluting Li-Ion Battery Electrode Crosstalk with Electrochemical Generator-Collector Measurements
Authors: Harris Oliver Clyde , Tang Maureen H 
Published: February 2020

Accelerated capacity fade in high-voltage Li-ion batteries is attributed to crosstalk between the positive and negative electrodes. During low potential operation of the negative electrode and high potential operation of the positive electrode, the nonaqueous electrolyte is reduced and oxidized, respectively, forming soluble, insoluble, and gaseous byproducts. Additionally, during electrolyte oxidation transition metals dissolve from active material of the cathode. After cycling, soluble species from the positive electrode are detectable at the negative electrode and are suspected to play an important role in disrupting the formation, growth, and performance of the solid-electrolyte interphase (SEI), leading to unmitigated capacity fade. In full-cell studies the effects of electrolyte decomposition and metal dissolution on battery lifetime and coulombic efficiency are well-documented, however the precise nature of crosstalk species and the mechanism of capacity fade remain to be understood.
Here we present two applications of our generator-collector approach to understanding battery crosstalk. First, we employ rotating-ring disk electrode (RRDE) voltammetry to study the effects of metal dissolution from LNMO (LiNi0.5Mn1.5O4) on SEI performance. By cycling an LNMO-coated glassy carbon disk to high operating potentials, we stimulate metal dissolution and collect these soluble species on the downstream glassy carbon ring electrode, which is cycling to low potentials to form and grow an SEI. The effects of metal contamination on SEI passivation are characterized via a redox mediator method and quantified using finite element simulations. We find that metal dissolution has a more profound impact on electronic than morphological SEI properties. Interpreting these results with physics-based models of SEI passivation imply that the inorganic layer is critical to passivation, while organic layers are inert at best.
In the second application, we demonstrate an improved method for performing generator-collector measurements on composite electrodes via the development of a microfluidic electrochemical cell. Our design incorporates commercial high-voltage positive electrodes, a graphite negative electrode, and commercial Li-ion battery electrolyte. Forced convection from electrolyte flow isolates the upstream electrode from crosstalk species generated at the downstream electrode, and deconvolutes the role of electrolyte oxidation and reduction on capacity fade. We study the effects of flow rate and flow direction on charge/discharge behavior for each electrode, and correlate coulombic efficiencies to the extent of crosstalk. These electrochemical generator-collector studies provide a greater understanding of the mechanism behind transition metal travel from the positive to negative electrode in a full-cell, as well as the importance of electrolyte decomposition in this transport mechanism.
Development of Novel Binders for Silicon Anodes for Lithium Ion Batteries
Authors: Lucht Brett , Chandrasiri Kaveendi 
Published: February 2020

High capacity electrode material has been studied over the years due to the constant demand for high energy density applications in li ion batteries. Among others, silicon has been considered a more promising candidate for its high theoretical capacity of ~ 3600 mAh/g, abundant resources, low cost and low toxicity. However, silicon-based electrodes face rapid degradation due to the extensive volume variation (~300%) in the charge discharge process. Binders used in the electrode fabrication plays a crucial role in these high-performance electrodes since it can reduce the mechanical fracture in the cycling process.
Utilization of polymeric material as binders to hold the active material has been the most common approach used in the li ion battery electrode preparation. Recent studies have shown the use of small molecular carboxylic acids as binders which showed an improvement in the cell performance for silicon electrodes. We will review various non-polymeric binder for silicon electrodes. Many of these alternative binders afford electrode preparation in water which reduces the introduction of toxic organic solvents such as NMP to the environment. The novel non-polymeric binders have better performance compared to PVDF. Surface morphology and Solid electrolyte interface was analyzed using electron microscopy techniques and spectroscopic methods and the results will be discussed.
Rational Design of Bian Based Anode Binder/Additive for High Performance Li Ion Secondary Batteries
Authors: Matsumi Noriyoshi , Patnaik Sai Gourang , Vedarajan Raman 
Published: February 2020

Bisiminoacenaphthene (BIAN) has been an important ligand structure for a variety of metal complex and widely employed as a ligand for olefin polymerization catalysts. However, in spite of their unique electrochemistry, it has not been widely utilized for energy devices. In the present work, firstly BIAN based novel conjugated polymer was prepared by Sonogashira-coupling polymerization and the obtained polymer (P-BIAN) was employed as anode binder in Li/EC:DEC/C type anodic half cells. Second, novel additive material bearing BIAN structure (BIANODA) was synthesized, which was used as additive to improve the characteristics of MNC cathode material (LiMn1/3Ni1/3Co1/3O2).
Electrochemistry of these materials along with characteristics of fabricated Li ion battery cells under these design protocol will be presented in detail.
The BIAN based polymer, P-BIAN shows lower LUMO level in comparison with ethylene carbonate (EC). This means reductive doping of P-BIAN takes place prior to reductive decomposition of EC at anode surface, which will restrict thick SEI formation at anode. When cyclic voltammetry measurements were carried out for coin cell with P-BIAN, peak due to reductive decomposition of EC was not observed, unlike the case of PVDF. Further, after charge-discharge cycles, coin cell with P-BIAN exhibited much smaller internal resistance when compared with PVDF. This indicates that reductive doping of P-BIAN and restriction of SEI decomposition had synergistically decreased internal resistance of battery cells. As a result, coin cell with P-BIAN showed 1.5 times higher discharging capacity in comparison with coin cell with PVDF.
On the other hand, BIANODA has higher HOMO level than that of EC, which enables oxidative polymerization of BIANODA prior to oxidative decomposition of EC. This will restrict thick SEI formation at MNC cathode surface. Use of Schiff base can trap HF generated during the cycling, and strong binding property of BIAN can stabilize MNC cathode for long term use. Consequently, BIANODA additive had enhanced the discharging performance of MNC/EC:DC/Li cathodic half cells.
Both P-BIAN as anodic binder material and BIANODA as MNC cathode additive were found to be remarkably effective to improve the performance of Li ion battery cells.
Reduced Surface Area Cathode Particles By Mechanofusion Processing
Authors: Zheng Lituo , Obrovac M. N. 
Published: February 2020

Polycrystalline layered-type cathode materials are usually in the form of spherical secondary particles consisting of an aggregate of primary particles. The surface of polycrystalline cathode particles contains features in the form of pits and valleys, leading to a high surface area. As the parasitic reactions with electrolyte occur at cathode surfaces, it is important to reduce the surface area in order to obtain long cycle life. Here, we present a study of using a mechanofusion method to reduce the surface area and improve the cycling performance of LiNi0.6Mn0.2Co0.2O2 (NMC622).
Figure 1(a) shows an SEM image of a pristine NMC622 particle. Primary particles can be seen clearly on the surface of a pristine NMC622 particle, resulting in a rough surface. Figure 1(b) shows an SEM image of an NMC622 particle processed with the mechanofusion method. After the mechanofusion process, the secondary particle size does not change. However, it is apparent that the surface has been smoothed compared to pristine NMC622. Figure 1(c) shows the voltage curve of materials processed using the mechanofusion method for varying times. Figure 1(d) shows the capacity retention rate of all the materials. NMC622 processed with mechanofusion method has better capacity retention than pristine NMC622, which is ascribed to its reduced surface area, resulting in reduced parasitic reactions with electrolyte.

Figure 1
Highly Safe and High Energy Density Lithium-Ion Battery Using Less Volatile Electrolyte
Authors: Unemoto Atsushi , Konishi Hiroaki , Nishimura Katsunori , Seki Eiji , Kawaji Jun , Okumura Takefumi 
Published: February 2020

Lithium-ion batteries (LIBs) are now used in the variety of fields including vehicles, and industrial and portable uses. Since the current LIBs use volatile and flammable electrolyte liquid, they have a risk on safety, e.g. explosion owing to an unexpected short. For ensuring the LIB safety, the cooling and safety mechanisms need to be installed in battery packs used for large scale applications, i.e. electric vehicles (EVs), and they compromise battery energy density and cost competitiveness.
To overcome the issue related to the LIB safety, we recently developed a novel electrolyte having the lower vapor pressure than the conventional organic liquid electrolyte, and incorporated it into LIB. High energy density of over 300 Wh/kg and high output power of over 1,600 W/kg were successfully demonstrated.
In the presention, the concept of our less volatile electrolyte, and evaluated results on performance of our highly safe, high energy density and high power LIB will be reported.
This work was supported by Innovative Science and Technology Initiative for Security, ATLA, Japan.