bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Catalysts Used in Redox Flow Batteries
Authors: Li Bin , Nie Zimin , Kizewski James , Duan Wentao , Wang Wei , Reed David , Sprenkle Vincent 
Published: February 2020

Redox flow batteries (RFBs), as one of the most promising electrical energy storage systems, provide an alternative solution to the problems of balancing power generation and consumption. RFBs are designed to convert and store electrical energy into chemical energy and release it in a controlled fashion when required. In particular, aqueous RFBs are attracting more attentions because of their good safety, low cost and high power density comparing with non-aqueous RFBs. Therefore, aqueous RFB chemistries with appropriate redox potential, high soluble and low-cost active species are critically required.[1]
During the past few years, PNNL invented several aqueous RFB systems, including mixed acid vanadium flow battery (VRB)[2]and zinc-polyiodide redox flow battery (ZIB)[3]. It is well known that high charge/discharge rate (charge/discharge current density) is prone to generate high power density, but the energy efficiency (EE) would be significantly declined. The low EE means that more active species are required for identical energy output, which eventually results in increased cost. In order to increase EE especially at higher current density, much attention has been paid on the improvement of electrodes. Commonly, carbon-based materials are used as electrodes in both VRBs and ZIBs because they are readily available, highly stable, corrosion resistant, economical and conductive. However, they were proved to show poor kinetic reversibility. Although noble metal catalysts such as Pt, Au, Ir, and Pd were coated or dispersed onto the carbon surfaces so as to improve the electrochemical activity of active species, the high cost still restricts their commercial application. Here, we will present our development at PNNL on low-cost and highly active catalysts, such as metal (Bi)[4], metal oxide (Nb2O5)[5], carbon oxygen functional groups[6] as well as metal-organic frameworks[7], used in VRBs and ZIBs, greatly enhancing the electrode performances. The corresponding mechanisms will be discussed in detail.
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References:

Li, B et al. L. National Science Review (2017): in press

Li, L et al. Advanced Energy Materials 1.3 (2011): 394-400.

Li, B et al., Nature communications, 2015

Li, B et al. Nano letters 13.3 (2013): 1330-1335.

Li, B et al. Nano letters 14.1 (2013): 158-165.

Li, B et al. ChemSusChem 9.12 (2016):1445-1461

Li, B et al., Nano Letters, 16. 7 (2016): 4335-4340
Dissection of the Voltage Losses of an Acidic Quinone Redox Flow Battery
Authors: Aziz Michael J. , Chen Qing , Gerhardt Michael R. 
Published: February 2020

We measure the polarization characteristics of a quinone-bromide redox flow battery with interdigitated flow fields, using electrochemical impedance spectroscopy and voltammetry of a full cell and of a half cell against a reference electrode. We find linear polarization behavior at 50% state of charge all the way to the short-circuit current density of 2.5 A/cm2. We uniquely identify the polarization area-specific resistance (ASR) of each electrode, the membrane ASR to ionic current, and the electronic contact ASR. We use voltage probes to deduce the electronic current density through each sheet of carbon paper in the quinone-bearing electrode. By interpreting the results using the Newman 1-D porous electrode model, we deduce the volumetric exchange current density of the porous electrode. We uniquely evaluate the power dissipation and identify a correspondence to the contributions to the electrode ASR from the Faradaic, electronic, and ionic transport processes. We find that, within the electrode, more power is dissipated in the Faradaic process than in the electronic and ionic conduction processes combined, despite the observed linear polarization behavior. We examine the sensitivity of the ASR to the values of the model parameters. The greatest performance improvement is anticipated from increasing the volumetric exchange current density.

Figure 1
Incorporation of Conductive Internal Additives within Electrocuring Adhesives
Authors: Steele Terry WJ 
Published: February 2020

Low-voltage activated adhesives have recently been invented, aka ‘voltaglue’, leading to electrochemically mediated adhesive curing (electrocuring)[1]. Consisting of new and established adhesive crosslinking groups, formulations incorporate dendrimers that have a preference of intermolecular crosslinking while allowing flexible incorporation of functional groups. Upon voltage activation, specific functional groups are activated and covalently bond to a variety of surfaces, but this is highly dependent on bulk conductivity.
To tailor the adhesive properties and adhesion strength, internal additives have been explored towards increasing conductivity and ultimately the ‘voltaglue’ crosslinking efficiency. Flexible electrocuring is sought to achieve a range of material properties, from viscous gels to hard set matrices. Ferrocene, a well-known redox active compound with reversible one-electron redox behaviour[2], is often incorporated in polymers/dendrimers due to its reversible nature and conductive aspects [3]. By integrating the ferrocene internal additive into dendrimer formulations combined with the electrically activated crosslinking additives we are able to mediate the electrocuring properties to a limited degree.
In this work we present the synthesis of PAMAM-g-ferrocene-g-diazirine, an electrocuring adhesive that is able to adhere to a range of substrates, with adhesive strengths at the kPa scale. Real time electrorheology measurements chemistry evaluate the range of material properties available and demonstrate the synergistic performance ferrocene internal additives impart on the ‘voltaglue’ adhesives.

References

[1] J. Ping, F. Gao, J.L. Chen, R.D. Webster, T.W.J. Steele, Adhesive curing through low-voltage activation, Nature Communications 6 (2015).
[2] M.E. N.P.R.A. Silva, A.J.L. Pombeiro, J.J.R. Fraústo da Silva, R. Herrmann, N. Deus, R. E.Bozak, Redox potential and substituent effects in ferrocene derivatives: II, Journal of Organometallic Chemistry 480 (1994).
[3] R. Gracia, D. Mecerreyes, Polymers with redox properties: materials for batteries, biosensors and more, Polymer Chemistry 4 (2013).
[4] C.M. Elson, M.T.H. Liu, C. Mailer, Electron-spin-resonance studies of diazirine anion radicals, Journal of the Chemical Society, Chemical Communications 7 (1986).
Synthesis of Co-Ni-Mo As Non-Noble Electrocatalysts for Ethanol Oxidation
Authors: Chaitree Wasu , Kalu Egwu Eric 
Published: February 2020

The high activity associated with platinum electrocatalyst for ethanol oxidation is tempered with its easy deactivation by CO species and its expensive nature as a noble metal. This work investigates the synthesis of highly active non-noble metal elctrocatalyst based on Cobalt (Co), Nickel (Ni), and Molybdenum (Mo) for ethanol oxidation. As-deposited Co-Ni-Mo electrocatalyst on carbon support was evaluated for ethanol oxidation. The electrocatalyst was prepared by electroless deposition method on carbon substrate support (CCS) made active for electroless deposition with Pd-ink. The effects of electroless deposition time, and reaction temperature (30-60°C) were studied. The result showed that CoNiMo/CCS was highly active in alkaline ethanol solution (0.5M NaOH+1 M EtOH) for ethanol oxidation. The temperature effect on the performance of the catalysts prepared at different times will be discussed. Although minor amount of Pd (< 50 μg/cm2) was used to make the carbon substrate active for electroless deposition, the results obtained showed that the Pd, was not utilized in ethanol oxidation. Therefore, the catalytic activity observed for the reaction is attributed to Co, Ni, and Mo, in the catalyst and not from Pd. Tafel analysis showed that the exchange current density for the catalyst prepared at 30 minutes deposition time was an order of magnitude higher than that reported for Pt (0.001´10-5A/cm2, [1]), and Pt/C (0.033´10-5A/cm2, [1]). This suggests that the catalyst has a better ability at handling CO deactivating species than Pt. Furthermore, the linearity of the peak potential with the logarithm of scanning rates confirms the irreversibility of ethanol electrooxidation . Overall, this study provides a promising novel and effective non-noble electrocatalyst with an onset potential of 0.05 V (Ag/AgCl).
[1]. Xu C, Shen PK, Ji X, Zeng R, Liu Y. Enhanced activity for ethanol electrooxidation on Pt–MgO/C catalysts. Electrochem Commun. 2005;7:1305–8.

Keywords: Cobalt, Nickel, Molybdenum, Electroless, Ethanol Oxidation, Tafel.
Tonic Dopamine Concentration Measurement Using Tailored Fscv
Authors: Cho Hyun-U , Oh Yoonbae , Shin Hojin , Park Cheonho , Kang Yumin , DeWaele Mark , Bennet Kevin E , Lee Kendall H , Jang Dong Pyo 
Published: February 2020

Fast-scan cyclic voltammetry along with its background subtraction method has been widely used for detecting neurotransmitters in the brain. The most common application of FSCV is measuring phasic changes of dopamine (DA) in the brain evoked by an external stimulus. The background subtraction method has greatly improved FSCV’s application to the neuroscience field. However, tonic dopamine concentration, which is as vital as phasic change, cannot be measured even though the background is subtracted. In this study, we developed a tailoring FSCV technique which can manipulate the background current by modifying a waveform’s voltage points. By using the technique, the last background current generated by multiple waveform application is tailored to the front background current. As a result, background current is cancelled out by subtracting the tailored (last) voltammagram from the front voltammagram. Therefore, only the DA oxidation/reduction pattern still remained between front and last voltammogram, so that, tailoring FSCV can detect tonic DA concentration without background subtraction method.
The tailoring technique is evaluated by comparing it with commercialized enzyme-linked immunosorbent assay (ELISA) kits. By measuring endogenously released DA from DAergic cells, the tailoring method showed a significant correlation with ELISA results.
Amorphous Transition Metal Polysulfides As Electrode Materials for Li-Ion Batteries
Authors: Doan-Nguyen Vicky V. T. , Subrahmanyam Kota S. , Butala Megan M. , Gerbec Jeffrey A. , Islam Saiful M. , Kanipe Katherine N. , Wilson Catrina E. , Balasubramanian Mahalingam , Wiaderek Kamila M , Borkiewicz Olaf J , Chapman Karena W , Chupas Peter J , Moskovits Martin , Dunn Bruce S. , Kanatzidis Mercouri G. , Seshadri Ram 
Published: February 2020

Sulfur cathodes in conversion reaction batteries operate by a different mechanism than that of intercalation materials, and they possess larger theoretical capacities. However, sulfur-based electrode materials suffer from parasitic polysulfide shuttling, which contribute to decreased capacity retention and cyclability. We demonstrate that porous transition metal polysulfide chalcogels achieve high gravimetric capacity as electrode materials for lithium-ion batteries. Transition metal polysulfide chalcogels are amorphous, and comprise polysulfide chains connected by inorganic linkers. The linkers appear to act as a “glue" in the electrode to prevent polysulfide shuttling. In particular, we examined 3d and 4d transition metal polysulfide chalcogels (M’M”Sx in which M is a transition metal) and their role in maintaining structural stability in the electrode. In the MoS3.4 case study, the Mo polysulfide chalcogels function as electrodes in carbonate– as well as ether–based electrolytes and achieve an initial gravimetric capacity of 600 mAh/g. We employ X-ray absorption spectroscopy and operando pair distribution function techniques to elucidate the structural evolution of the electrode. Raman and X-ray photoelectron spectroscopy track the chemical moieties that arise during the anion-redox-driven processes. We find the redox state of Mo remains unchanged across the electrochemical cycling even to 1 V and correspondingly, the redox is anion–driven. Porous chalcogels offer a new class of electrode materials for achieving high-capacity Li-ion batteries.
Data Science Tools for Incorporating Physics-Based Models into Analysis of Impedance Spectra
Authors: Murbach Matthew D. , Schwartz Daniel T. 
Published: February 2020

Electrochemical impedance spectroscopy (EIS) is a widely used method for noninvasively characterizing many electrochemical systems – probing the physicochemical response at different timescales to provide insight into a wide range of kinetic, transport, and thermodynamic parameters. By fitting equivalent circuit analogs to experimental impedance spectra, lumped parameters (ohmic and charge transfer resistances, double layer capacitances, Warburg impedances, etc.) which contain information about the physicochemical properties of the system are extracted. While this usage of equivalent circuit models makes fitting the data straightforward, the lumped parameter nature of this process can lead to limitations on the information content and discriminatory power of these measurements.1,2 Moreover, while the extracted parameters are often used as inputs to complex physics-based models, the reverse flow of information – directly incorporating modeling insights into the analysis of experimental impedance spectra – remains challenging for many researchers using EIS.
Here, we present an open-source, web-based tool for easily integrating physics-based modeling into the analysis of experimental impedance data. Using a large dataset of simulated spectra across a well sampled physical range of model parameters, the best fit of an experimental dataset can be used to find parameter estimates for the model. This data driven approach enables a more robust method for finding parameter estimates than optimizing the model directly and visualizations of the resulting best estimates give researchers the tools to more deeply analyze their data. Interactive visualizations of the simulated spectra also make it possible to ask more insightful questions about the model itself. As an example, we present a dataset of impedance simulations from a pseudo 2-dimensional (P2D) lithium ion battery model3,4 and describe insights gained by incorporating this dataset into analysis of experimental battery impedance spectra. Finally, we discuss the tool as an extensible platform for adding additional modeling datasets and features from across the community and the role of open-source tools within electrochemistry.

References:

1. Fletcher, S. Tables of Degenerate Electrical Networks for Use in the Equivalent-Circuit Analysis of Electrochemical Systems. J. Electrochem. Soc.
141, 1823–1826 (1994).
2. Harrington, D. A. & van den Driessche, P. Mechanism and equivalent circuits in electrochemical impedance spectroscopy. Electrochimica Acta
56, 8005–8013 (2011).
3. Doyle, M., Meyers, J. P. & Newman, J. Computer simulations of the impedance response of lithium rechargeable batteries. J. Electrochem. Soc.
147, 99–110 (2000).
4. Meyers, J. P., Doyle, M., Darling, R. M. & Newman, J. The impedance response of a porous electrode composed of intercalation particles. J. Electrochem. Soc.
147, 2930–2940 (2000).
3D Microscopic Simulation of Mediator Supercapacitors
Authors: Wang Yuchen , Zhang Chen , Qiao Xiaoyao , Zhou Xiangyang 
Published: February 2020

Supercapacitors (SCs) can reach a high specific energy (25-50 Wh/kg) by doping mediators in electrolyte contained in porous electrode structure. Mediators in electrolyte can be considered as redox materials to provide pseudocapacitance and to increase the conductivity of electrolyte. However, the charge/discharge behaviors of the mediators with respect to current and voltage are difficult to be resolved because of the complicated structure and charge/discharge kinetics of the electrode materials. In this work, a 3D microscopic model is established to investigate the roles of different components, especially mediators in charge/discharge processes. The microscopic model (Figure 1) is solved using COMSOL Multiphysics. Activated carbon, carbon fibers, mediators and polymer electrolyte are explicitly represented in this model. The simulation describes the process after applying a voltage on the mediator SC. During charging, electric current flows into the mediators at positive electrode and flows out from the mediators at negative electrode. The charge rate at electrical double layers is much faster than the charge rate for the mediator domains due to different charge storage mechanisms. The mediators can only store the charges at the certain potential range. With the increase of the mediator capacitance, the time to reach a stable state increases. The mediators can also affect the stable potential of the electrolyte. As such, the model can be used to design the composition of the mediator SCs and predict the effect of mediators on the performance of the mediator SCs. In addition, the information regarding the stable electrolyte potential vs. mediator capacitance can be used to choose the electrolyte with specific potential windows to avoid electrolyte degradation at electrode/electrolyte interface.

Figure 1
Simulation of the Impact of the Loss of Contact Area in All-Solid-State Battery
Authors: Tian Hong-Kang , Qi Yue 
Published: February 2020

Maintaining the physical contact between the solid-state electrolyte and the electrodes is important to improve the performance of the Li-ion battery. The initial interface contact depends on the fabrication process of the battery. Typically, the deposited thin-film battery would have better interface contact than the bulk-type (mixed powder) battery. Increasing the compression pressure during the fabrication process could lead to a better initial contact. On the other hand, the contact area would continuously lose due to the volume change of the electrodes during the cycling of the battery.
To illustrate this problem, a 1-D continuum model was developed to simulate the discharging process of an all-solid-state Li-ion battery, which is composed of Li as the anode, LiCOO2 as the cathode, and Li3PO4 as the electrolyte. The parameters were taken from a thin-film battery model that has fitted to experimental data. We incorporated the effect of the imperfect contact into this model by assuming the current and Li concentration will be localized at the contacted area. We correlated the percentage of lost contact area with the discharging capacity and energy. We observed that the capacity and energy decrease with the loss of contact area and discharge rate. For example, when discharging at 1 C-rate, the capacity decreased 20% as the contact area losses 19.8%. At a higher discharging rate of 32 C, the capacity dropped quickly to be less than 20% when the contact area losses 1.52%.
Since Li3PO4 and LiCOO2 are both ceramic materials and their initial contact area is non-perfect after the fabricating process. We applied the Johnson-Kendall-Roberts (JKR) model, which is appropriate for elastic deformation and adhesive contact, to estimate the applied pressure that can recover the loss of contact to the initial condition. We found that it is more effective to apply the pressure when the battery just starts to decay when the battery capacity loss is less than 10%. Therefore, in practical application, this model and method can be used to estimate the extent of the loss of contact area during the operation of the all-solid-state Li-ion battery, and further suggesting how much pressures should be applied to recover the capacity.
Pulse Reverse Electrolytic Stripping of Chrome Plate
Authors: Garich Holly , Snyder Stephen , Hall Timothy D , Taylor E. J. , Inman Maria 
Published: February 2020

A strong desire exists from an environmental, health and safety perspective to eliminate hexavalent chromium during electroplating of protective hard chrome coatings used to enhance component wear resistance. However, toxic hexavalent chromium waste streams are also generated during repair and refurbishment of chrome components as the parts are electrolytically stripped of the existing chrome before being recoated and reinstalled into various systems. Furthermore, the chromate formed during stripping accumulates in the electrolyte, interfering with the process efficiency and damaging the base metal.
Faraday is working to develop an electrolytic stripping process intended as a drop-in replacement for the conventional stripping process. The process seeks to eliminate the formation of hexavalent chromium while maintaining the material properties of the underlying substrate.
Faraday will present work that demonstrates removal of chrome from high strength steel substrates using a weak acid electrolyte that doesn’t produce hexavalent chromium or adversely affect the substrate properties. Furthermore, the effect of pulse and pulse/reverse electric fields on the efficacy of the stripping process will be presented.
(Invited) Structural Evolution of Hafnium Methacrylate Nanoclusters Following Electron-Beam Irradiation from in Situ ir Spectroscopy
Authors: Mattson Eric , Rupich Sara , Cabrera Yasiel , Chabal Yves J 
Published: February 2020

High absorption metal and main group oxide nanoclusters have recently become the subject of intense investigation due to their potential as alternatives to conventional organic chemically amplified photoresists for negative tone patterning in the extreme ultraviolet (EUV) range. It is believed that the low energy secondary electrons generated from photoionization of the nanoclusters are responsible for the chemistry that occurs following irradiation. Despite their potential, little is known about many aspects of their function as resist materials; in particular, the role of high absorption elements in the absorption/photoionization process, the role of electrons of different energies, the formation of radicals and chemically reactive species and the overall structural changes that occur at each stage of processing. Thus, the precise atomic mechanism underlying solubility switching upon irradiation remains unknown. We have investigated one such class of materials: nanoclusters based on a hafnium oxide core decorated with methacrylic acid ligands (HfMAA) , using a combination of in situ infrared (IR) spectroscopy and x-ray photoemission spectroscopy (XPS). Thin films (10-30 nm) of the HfMAA nanoclusters deposited onto SiO2 from solution are characterized by XPS and IR spectroscopy in conjunction with density functional calculations. The mechanisms of solubility switching following EUV exposure are investigated using irradiation with low energy electrons to emulate the photoexcited carriers generated in the EUV absorption process. Using in situ IR spectroscopy, we are able to monitor the structural evolution of the nanoclusters at each stage of processing, beginning from the initial deposition to post application bake (PAB), electron irradiation, post exposure bake (PEB) and development. Monochromatic electron beams with energies ranging from 5 eV up to the typical EUV wavelength of 92 eV enable a correlation between the role of secondary electron energy with chemistry and functional character. In conjunction with XPS analysis, these measurements detail the structural evolution of the films under typical processing conditions, providing insight into the solubility switching mechanism of this emerging class of inorganic photoresists.