bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Modification of Surfaces By the Diazonium Chemistry
Authors: Bélanger Daniel 
Published: February 2020

Modification of surfaces is currently a very active field of research. Modification by using organic molecules as precursor is attractive due to the large variety of available compounds. Although the electrochemistry of diazonium salts has been studied for more than 50 years, it was not until the early 1990s, that the formation of a film resulting from the electrochemical reduction of such salts have been demonstrated. Since then, many fundamental studies have led to a better understanding of the various processes involved in the grafting reaction. In the presentation, a brief summary of some important findings on the subject made by our group will be made. Also the presentation will show the new approaches currently developed in our laboratory for the chemical and electrochemical modification of surfaces.
Molecular Au25(SR)18 Nanoclusters: Lifetime of Electrogenerated Species and Dielectric Properties of the Protecting Monolayer
Authors: Antonello Sabrina , Dainese Tiziano , Maran Flavio 
Published: February 2020

We used a series of molecular Au25(SCnH2n+1)18 clusters (n = 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18) to study the effect of n and the presence of electrolytes on their redox potentials. We found that the average dielectric constant of the monolayer, ε
m, depends on n and is the result of contributions from ligands, solvent and electrolyte. When n increases, ε
m decreases until a virtually constant value is attained for sufficiently long ligands. The electrochemically calculated HOMO-LUMO energy gap, on the other hand, does not depend on n and, therefore, ε
m.1 We also studied the effect of n on the lifetime of electrogenerated species. Whereas on the voltammetric timescale the -1, 0, and +1 charge state of Au25 clusters are stable, formation of the -2 and +2 states causes fragmentation of the cluster. Voltammetric analysis indicates that the former entails reactions involving ligands in the Au12(SCnH2n+1)18 protecting shell, whereas the latter is accompanied by a slower but also more substantial fragmentation affecting the integrity of the central Au13 core. 2

References
1. Antonello, S.; Dainese, T.; De Nardi, M.; Perotti, L.; Maran, F. Insights into the Interface Between Electrolytic Solution and Gold Core in Molecular Au25(SR)18 Clusters. ChemElectroChem.
2016, 3, 1237–1244.

2. Antonello, S.; Dainese, T.; Maran, F. Exploring Collective Substituent Effects: Dependence of the Lifetime of Charged States of Au25(SCnH2n+1)18 Nanoclusters on the Length of the Thiolate Ligands. Electroanalysis
2016, 28, 2771-2776.
Developing New Synthetic Methods for the Construction of Complex Molecules and Complex Molecular Surfaces
Authors: Moeller Kevin D 
Published: February 2020

Electrochemical methods enable the generation, study, and utilization of reactive intermediates that are derived by reversing the polarity of known functional groups. In this way, they provide a unique method for exploring new reactions that would not otherwise be possible. In the talk to be presented, two such methods will be discussed.
In the first, we have been examining both radical cation and radical intermediates that are generated under net oxidative conditions. The reactions can be used to generate a wide variety of new bonds and ring systems. Recently, we have been focusing on two aspects of the reactions. First, how the reactions can be best incorporated into a synthetic sequence so that either radical cation or radical pathways can be utilized. The key is the development of a rapid means to generate either enol ether or endiol substrates for the electrolysis and then a study of the subsequent reactions (Scheme 1). Second, we have been examining how mechanistic insight into the nature of the reactive intermediates generated can be used to overcome synthetic barriers that have in the past limited use of the reactions.
In the second method to be discussed, electrochemistry and the ability it offers to generate and control new umpolung reactions is being used to conduct the total synthesis of complex molecular surfaces. The reactions range from transformations that convert synthetically optimized surfaces for use on microelectrode arrays into surfaces optimized for subsequence signaling studies (Scheme 2) to methods for the diversification of molecular scaffolds on an array. All of the reactions utilize electrochemical methods to shape the way synthetic challenges are addressed.
In the talk to be given, selected examples from both methods will be used to illustrate how a basic understanding of electrochemical reactions can be used to solve a diverse array of synthetic challenges.

Figure 1
Iron Phosphide Nanoparticles As an Efficient Electrocatalyst for the Oxygen Evolution Reaction in Alkaline Solution
Authors: Umapathi Siddesh , Masud Jahangir , Ashokan Nikitaa , Nath Manashi 
Published: February 2020

Splitting water to hydrogen and oxygen through hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is basis to feed the fuel cell. OER is a thermodynamically uphill process as it requires higher potential to form O2 molecule. The best known catalysts to split water with low overpotential are the oxides of Ir and Ru. As these catalysts are precious metals there has been intensive research to substitute them with earth-abundant resources. The new catalyst should fulfill the following: (i) the catalyst to split water has to use minimal energy (measured as applied voltage and referred to as overpotential); (ii) should comprise of earth abundant elements; (iii) should be stable; (iv) should be scalable.1 Transition metal oxides have been recently identified as high-efficiency catalysts for oxygen and/or hydrogen evolution reaction. Apart from the oxides there has been reports of sulfide, selenide and nitride based catalysts.2 Although transition metal phosphides has recently gathered attention as HER catalysts,3 very less metal phosphides have been reported as OER electrocatalyst. In this presentation, ultra-small iron phosphide nanoparticles as well nanoparticle composite with reduced graphene oxide (FeP-rGO) has been reported as efficient electrocatalysts for OER under alkaline conditions. FeP nanoparticles require an overpotential of 290 mV @ 10 mAcm-2. It is well known that rGO is a good conductor and a support material for the catalysts. Hence, mixing of FeP nanoparticles with rGO has improved the catalytic efficiency further by reducing the overpotential to 260 mV to achieve 10 mAcm-2 current density4. The FeP nanoparticles and FeP-rGO composite showed the lowest overpotential at 10 mA/cm2 that has observed among the pnictide making these the most-efficient phosphide based OER catalyst till date. The hybrid catalyst showed a low Tafel slope of 50.8 mV/dec. The stability of the catalyst was excellent with 4h of continuous oxygen evolution and the catalytic activity was retained with a similar overpotential @ 10 mAcm-2. The synthesis of hybrid catalysts, detailed characterization, and electrochemical studies including liner scan voltammetry (LSV), choronoamperometry will be discussed in detail.
References:

Bard, A. J.; Fox, M. A. Artificial photosynthesis solar splitting of water to hydrogen and oxygen. Acc. Chem. Res.
1995, 28, 141-145

Swesi, A. T.; Masud, J.; M. Nath. Nickel selenide as a high-efficiency catalyst for oxygen evolution reaction. Energy Environ. Sci.
2016, 9, 1771-1782.

Popczun, E, J.; Read, C, G.; Roske, C, W.; Lewis, N, S.; Schaak, R, E. Highly Active Electrocatalysis of the Hydrogen Evolution Reaction by Cobalt Phosphide Nanoparticles. Angew. Chem. Int. Ed. 2014, 53, 5427 –5430.

Masud, J.; Umapathi, S.; Ashokaan, N.; Nath, M. Iron phosphide nanoparticles as an efficient electrocatalyst for the OER in alkaline solution. J. Mater. Chem. A, 2016,4, 9750-9754.

Figure 1
(Keynote) Investigation the Effect of CO2 Absorption in Anion Exchange Membrane By Electrical Conductivity and NMR
Authors: Peng Jing , Roy Asa Logan , Elgammal Ramez Ahmed , Zawodzinski Thomas A. 
Published: February 2020

The anion exchange membrane (AEM) has attracted considerable attention in the application of fuel cell technology. Compared with proton exchange membrane fuel cells, AEM fuel cells (AEMFCs) have advantages in cost, catalyst stability, efficiency and system size1. However, one challenge in the application of AEMFCs is the absorption of CO2 from the cathode air supply, which forms carbonate and bicarbonate species and reduces the ionic conductivity of membrane.
In this study, to better understand the effect induced by CO2 on AEM performance, the ion transport mechanism was investigated by using electrical conductivity and Nuclear Magnetic Resonance (NMR) techniques. A typical commercial anion exchange membrane Tokuyama A201 has been used for all experiments. OH- form membranes are prepared by soaking in low concentration (10-4 M) KOH solution. CO3
2- and HCO3
- form membranes are used after soaking in 1M K2CO3 or KHCO3 solution. Both electrical conductivity and NMR experiments have been performed on a series of OH- form, CO3
2- and HCO3
- form samples with different water contents from 20 °C to 80 °C. Figure 1 shows the electrical conductivity of HCO3
- form A201 at different relative humility as a function of temperature, which displays an increasing trend as the relative humility and temperature increase. Also note the low values of conductivity relative to that expected from a hydroxyl ion conductor. This is in accord with previous reports that indicate a significant decrease in conductivity upon uptake of CO2 into hydroxide-form membranes. 1H and 13C pulse-field-gradient NMR are used to characterize the speciation and diffusion coefficient D(NMR)
of water, CO3
2- and HCO3
- respectively. Difference in ionic conductivity and diffusion coefficient of each species in the membrane between three different forms can be observed. The estimated diffusion coefficient D(σ) from ionic conductivity obtained by using Nernst-Einstein equation is sometimes different from that measured by NMR. The comparison between D(NMR)
and D(σ) provides valuable information on ionic transport mechanism 2. Obtaining dynamic information on the behavior of CO2– derived species in the membrane will allow modeling to the distribution of such species in the membrane.
Acknowledgement.
We gretefully acknowledge the support of this work by the Office of Naval Research. We also appreciate the assistance of Tokuyama Soda in providing A201 membrane samples.
Reference:
1. X. M. Ren, S. C. Price, A. C. Jackson, N. Pomerantz and F. L. Beyer, Acs Appl Mater Inter, 6, 13330 (2014).
2. S. Ochi, O. Kamishima, J. Mizusaki and J. Kawamura, Solid State Ionics, 180, 580 (2009).

Figure 1
Controlled Ion Flow through Polymeric Anion Exchange Membranes
Authors: Pantelis Demetra M , Experton Juliette , Martin Charles R 
Published: February 2020

Ion-selective polymeric membranes are integrated in electrodes for measuring concentrations of specific ions. The Nernst equation (Eq. 1) allows the ion activity of an unknown sample, a
out, to be calculated from activity of a known internal reference solution, a
in, and the potential across the membrane, E
m­.
(Equation 1)

R, T, z and F are the gas constant, temperature, charge of the analyte ion and Faraday’s constant, respectively.
While this logarithmic form of the Nernst equation has practical applications in analytical chemistry, the equation can also be written in the exponential form (Eq. 2).
(Equation 2)
This suggests an alternative application where a potential E
app drives ions across the membrane until the ratio of activities satisfies Equation 2. In drug delivery, for example, this provides a method to quantitatively transport a specific drug through a membrane. The delivery rate scales with the current applied across the membrane and dissipates when an equilibrium state is reached. At this point, the activity ratio provides a membrane potential, E
m, equal and opposite to the applied potential, E
app.
We have developed a device to monitor ion flow through a quaternary ammonium gel polystyrene membrane. Applying a potential across this anion exchange membrane resulted in the quantitative delivery of nitrate ions until the activities verified Equation 2. This suggests that dosage-controlled and selective drug delivery can be obtained using this membrane.

Figure 1
Partial Battery Abuse Tests to Determine Battery Stability with Advanced Diagnostics
Authors: Torres-Castro Loraine , Lamb Joshua , Steele Leigh Anna M , Dufek Eric J. , Walker Lee K. , Orendorff Christopher J. 
Published: February 2020

Traditional monitoring of electrochemical cells and batteries has been limited to observation of voltage and temperature of the cell or cells. While this monitoring can be very robust, there are limits to how predictive voltage and temperature behavior can be prior to a thermal runaway event. Ultimately, voltage and temperature changes are often lagging indicators or symptoms of battery failure, and by the time a noticeable change is detected it is too late to arrest cell failure with intervention or maintenance. Further, instantaneous voltage and temperature monitoring are often inadequate to determine the state of a battery at rest, particularly if the battery has been previously subjected to an abusive condition. Knowledge of the level of stability of a damaged battery would allow for both safer and more efficient handling of the abused battery.
This work examines the application of Electrochemical Impedance Spectroscopy (EIS) and Differential Capacity calculations (dQ/dV) as a tool for determining the state of stability (SOS) of an electrochemical cell or battery. The cells for this study were subjected to thermal and electrical abuse coupled with EIS monitoring at differing levels of battery abuse. This aims to not only provide a deeper understanding of how abused cells and batteries fail, but also form the technical basis of a tool that could ultimately be used to interrogate cells of an unknown stability and even monitor active cells for early signs of damage or failure. Fast impedance monitoring hardware previously developed at Idaho National Laboratory is used to provide not only monitoring after an abusive battery test but also look for changes in the cell while abusive conditions are applied. Differential capacity calculations are explored both after tests and during moderate levels of overcharge to explore any observable changes that may be monitored during charge and discharge operations. These markers could then be potentially applied to cross-examine batteries of an unknown stability as well as provide the basis for an active diagnostic method as part of a battery management system.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Modeling Thermochemical Sources for a Broader Range of Materials and Conditions
Authors: Shurtz Randy C. , Hewson John 
Published: February 2020

The past two decades have seen the development and implementation of models from calorimetry data that are useful for predicting the onset of thermal runaway in a single Li-Ion cell. This work looks toward further capabilities that can be extracted from calorimetry measurements. These include enabling heat release predictions that allow cell-to-cell propagation of thermal runaway; this requires more comprehensive models that include the effects of additional processes that occur after the onset of thermal runaway. Some of these additional processes are identified from calorimetry data and incorporated into models. The updated models are used to show how all of the identified high-temperature processes contribute to the total heat and gas generated during thermal runaway of Li-Ion cells. The implications for propagation scenarios are discussed.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
SAND NO. 2016-12692 C
Addressing Lithium-Ion Battery Reliability: A Survey of Electrochemical Behavior
Authors: Barkholtz Heather Marie , Fresquez Armando , Chalamala Babu , Ferreira Summer 
Published: February 2020

Over the last three decades, lithium-ion batteries (LIBs) have emerged as premier electrochemical energy storage devices. Their widespread application includes cell phones, laptop computers, hybrid electric vehicles, etc. Today, this technology is applied to grid-level energy storage, supporting renewable energy integration into existing power grid infrastructure. To support increasing demand for long-term, large-scale LIB systems; a deeper understanding of commercial LIB safety and reliability is required. Despite thousands of published articles detailing development of LIB components, comparative studies of electrochemical performance as a function of application environments and conditions are scarce. Specifically, parameters such as: cycle stability, capacity, rate capability, cost, and safety implications must be defined as a function of reasonable operating temperatures. Herein, a survey of the electrochemical performance of several commercially available lithium-ion 18650 cells is reported. These studies describe the electrochemical response to temperatures and discharge currents within manufacturer specifications. Electrochemical impedance spectroscopy was used in conjunction with charge/discharge testing to help identify the mode of capacity fade under specific conditions. Several common phenomena occur within these systems, which are reviewed and discussed with a focus on their advantages and disadvantages.
Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. SAND2016-12467 A
(Invited) Alternative Battery Failure Initiation Methods
Authors: Lamb Joshua , Steele Leigh Anna M , Orendorff Christopher J. 
Published: February 2020

Propagating battery failure, where the energetic failure of a single cell leads to a cascading thermal runaway of other cells within a battery system, is of increasing concern as battery systems become larger and include greater numbers of cells. However, testing cell to cell propagation requires a method for initiating or simulating single cell runaway while adding a minimum of excess energy into the system. Traditionally single cell failure is initiated with standard battery abuse tests, such as overcharge, thermal ramp and nail penetration tests. However, nail penetration tests can be difficult to perform in fully developed battery systems while overcharge and thermal ramp add a significant amount of excess energy into the battery system. Recent work at Sandia has looked at non-traditional thermal runaway triggers that can be applied to off-the-shelf cells. Heat generation from a single cell was determined through accelerating rate calorimetry (ARC) and used to determine the total flux needed from high power quartz lamps to simulate the thermal runaway of a nearby cell. This was then used to initiate single cells with radiative heating. Single cells were also initiated using a fiber coupled laser to create a localized failure on a cell. This was evaluated for multiple laser energy levels and cell orientations, and coupled with CT evaluation of the point of failure.
Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
Modeling Thermal Runaway in Li-Ion Packs As a Function of Scale and Heat Source
Authors: Shurtz Randy C. , Hewson John 
Published: February 2020

As deployment of large-scale Li-Ion battery modules is contemplated, there is a need to understand the propensity for thermal runaway in individual cells and the large-scale thermal failure at the module level. Sources of thermal energy that can lead to runaway include short circuits (internal or external), exothermic processes from overcharge of imbalanced cells, the external environment, and other factors. With battery modules consisting of hundreds or even thousands of cells, it will be necessary to design tolerance to local heat release, regardless of the source. This work presents a chemistry-independent framework for analyzing and modeling thermal runaway that will be demonstrated by applying it to multiple lithium-ion cell chemistries to also demonstrate the sensitivity to the cell chemistry. The combined effects of module scale and the thermal environment surrounding the battery are considered in detail.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.
SAND NO. 2016-12691 C
Numerical Investigation of Thermal Runaway Propagation Induced By Internal Short Circuits in Li-Ion Cells
Authors: Li Qibo , Yang Chuanbo , Smith Kandler , Keyser Matthew , Pesaran Ahmad 
Published: February 2020

It is known that potential safety risks of Li-ion battery limit their applications. Thermal abuse, which is induced by internal short circuit, is the most dangerous scenario among various safety risks. Numerous studies of internal short circuit have been done by experimental approach. However, experimental methods cannot provide sufficient information to show the mechanism of thermal runaway propagation during internal shorting. Recently, a comprehensive three-dimensional safety model for Li-ion cell, which is based on a multiscale multi-dimensional (MSMD) battery modeling methodology, has been developed by energy storage group in NREL. This safety model, which includes three sub-models, provides a unique capability to investigate the effects of internal short circuit on thermal runaway propagation in a Li-ion battery. In term of sub-models, electrochemical model is used to simulate electrochemical reaction of Li-ion battery; internal short circuit model and thermal abuse model are used to predict the behavior of thermal runaway. In this study, three-dimensional simulations with internal short circuit have been done by applying the safety model. The numerical approach was validated by an experiment utilizing an internal short circuit device, and the results were analyzed in time domain and frequency domain. The mechanism of thermal runaway propagation was discussed, and the dominant parameters to lead thermal runaway were identified. The simulation results reveal the behavior of thermal runaway is affected by initial short volume and short resistance as well as electrical resistance of the electrodes.