bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Organized Ferrocene-Functionalized Nanoporous Silica Films with an Extremely Fast Electron-Transfer Rate for an Intrinsically Nonconducting Oxide-Modified Electrode
Authors: Audebert Pierre , Vila Neus , Allain Clémence , Walcarius Alain , Hapiot Philippe
Published: February 2020

Modified electrodes from functionalized nanoporous xerogel coatings, prepared by using the electrochemically assisted self-assembly (EASA) method, containing ferrocene moieties grafted onto vertically oriented pores perpendicular to an indium-tin oxide (ITO) electrode, have been prepared and studied. The electrochemical behavior of these new materials exhibits the fastest charge transfer ever observed in oxide-modified electrodes. The cyclic voltammetry curves allow us, however, to discriminate two types of ferrocene species inside the coatings and to determine the rate constants for the electron exchange between the ITO electrode and the coatings, with the help of simulations and an advanced software package1.

Fig. 1: Scheme depicting the electrode building.

While it is not clear why the charge transfer is so fast, some hypotheses will be presented along.

1 P. Audebert, N. Vila, C. Allain, F. Maisonneuve, A. Walcarius, and P. Hapiot ChemElectroChem 2015, 2,1695.

Figure 1
(Keynote) Sunlight-Driven Ionic Power Production Using Ion-Conducting Polymers
Authors: White William , Sanborn Christopher D. , Reiter Ronald S. , Cardon Joseph M. , Ardo Shane
Published: February 2020

Ion-conducting polymers are passive. They respond to electric biases that are applied across them by transporting ions via migration. However, there is no reason these materials cannot be made active, such that upon absorption of light, ions are driven in directions pre-defined by built-in potential distributions in the materials and collected via selective contacts to generate power. This is exactly how traditional solid-state solar cells work and the physics that dictates this behavior only requires that the mobile carriers be charged, like ions, and not that they specifically be electrons and/or holes.

My research group studies solar energy conversion technologies that generate power from sunlight absorption through ion transport. In my presentation I will report on my research group’s recent demonstration of ion transport against concentration gradients that was driven by solar illumination of dye-sensitized ion-conducting materials. Mechanistically, visible light was used to drive endergonic excited-state proton transfer from a covalent photoacid-modified cation-conductive membrane. Photoacid molecules convert the energy in light into a change in the chemical potential of a proton via weakening of a protic functional group on the photoacid, i.e. a decrease in its pK
a. A cation-conductive membrane served as the selective contact for protons such that absorption of light resulted in photovoltaic action, i.e. a photocurrent and a photovoltage. Bipolar membranes are another class of ion-conductive polymers that were used to demonstrate similar photo-activity. They consist of a monopolar cation-conductive polymer that is in intimate contact with a monopolar anion-conductive polymer. The physics that describes the ion-equilibration processes within bipolar membranes resembles that which occurs during equilibration of semiconductor pn-junctions.

As a model system for ion-channels in phase-segregated ion-conducting polymers, dye-sensitized conical nanopores in poly(ethylene terephthalate) (1 – 108 pores/cm2) were investigated. Remarkably, in a region occupied by ~20 zeptoliters (~2 x 10-20 L) of aqueous electrolyte, electrochemistry and fluorescence microscopy were used to determine the photoacidity of the surface-bound dye molecules, which changed from the values found in bulk solution, likely as a result of surface charges in the confined nanopores.

This body of work represents an underappreciated solar energy conversion process that is being pioneered by my research group to operate via a mechanism similar to that of semiconductor pn-junctions. The applicability and practicality of these materials as standalone devices for desalination of salt water will also be presented.
(Invited) Durability of Electrochromic Films: Ageing Kinetics and Rejuvenation
Authors: Niklasson Gunnar A. , Wen Rui-Tao , Qu Huiying , Arvizu Miguel A , Granqvist Claes-Goran
Published: February 2020

A major challenge for energy-efficient smart window technology is to ensure the durability of electrochromic (EC) devices over a service life of more than 20 years. Hence, their degradation under operating conditions must be better understood and preferably avoided. In this paper we review our recent results from a fundamental study of the ageing kinetics of EC tungsten oxide and nickel oxide thin films, as well as electrochemical rejuvenation mechanisms that are able to restore the films to their initial state. The ageing of tungsten oxide films upon cycling in the range 2-4 V vs. Li/Li+ displays a power-law decrease of the charge capacity as a function of cycle number. In the case of severe ageing at potentials below 2.0 V there is evidence for a superposition of two processes. In the case of nickel oxide the ageing process seems to be more complex and it can be described by either a power-law or a stretched exponential function. The ageing of nickel oxide was also observed to decrease and even stop after a few thousand cycles just prior to final breakdown of the film. The decay of charge capacity can be understood in terms of models built on so-called dispersive chemical kinetics.

The term “rejuvenation” describes electrochemical processes that may restore aged films to full EC functionality. During severe ageing of tungsten oxide coatings, Li ions are trapped in the film, and subsequently these ions can be released by application of a high electrochemical potential for a few hours. The trapping/detrapping of Li has been verified by Elastic Recoil Detection Analysis (ERDA) measurements. Very recently we have found that a similar process can be applied to EC nickel oxide films, although using a lower potential than for the case of tungsten oxide. For nickel oxide, the rejuvenation mechanism is not yet clear, but ERDA measurements are in progress and are expected to give detailed information.

An increased understanding of ageing and rejuvenation will facilitate large-scale practical application of electrochromic materials. Our phenomenological models of ageing may make it possible to predict the service life of EC devices using empirical relationships. An understanding of rejuvenation processes will be of major importance in order to prevent or minimize performance decrease under extended cycling. The next step will be to investigate whether rejuvenation treatments can be applied successfully to full EC devices.
Reflective Electrochromic Device with Gelatin-Nanocomposite Electrolyte
Authors: Sentanin Franciani C , Sabadini Rodrigo César , Cavalheiro Carla C , Kanicki Jerzy , Silva M. M. , Pawlicka Agnieszka
Published: February 2020

Reflective electrochromic device with glass/Cr/PB/electrolyte/CeO2-TiO2/ITO/glass configuration was assembled and characterized. Prussian blue (PB) thin film was electrodeposited galvanostaticaly at -40 µA/cm2 for 180 s from a solution of K3[Fe(CN)6] (0.05 mol/L), FeCl3
.6H2O (0.05 mol/L), and HCl (0.1 mol/L) on chrome coated glass as working electrode. CeO2-TiO2 thin film was obtained from sol-gel method and deposited by dip-coating on ITO conductive glass at 20 cm/min. This coating was heat treated at 450°C for 15 min. As electrolyte, there was used gelatin-nanocomposite membrane prepared by casting from mixture of gelatin, LiClO4, and clay (SCa-3) at concentrations of 10, 15, and 20 wt% solution. The electrolyte was characterized by ionic conductivity properties, and the one with 15 wt% of clay was applied in ECD. This electrolyte displayed the ionic conductivity of 6.46x10-5 and 6.02x10-4 S/cm2 at 25 and 70°C, respectively. The ECD was subjected to reflectance measurements that revealed a change from 8 to 15% at 450 nm for bleached and colored states, respectively. The picture of colored and bleached states is shown in Fig. 1. Moreover, this ECD demonstrated to be completely reversible. Finally, it was shown that reflective ECD with nanocomposite electrolyte based on natural macromolecule and clay have promising performance for display application.

Figure 1
A Miniaturized High-Throughput Flow Injection Analysis System for Electrochemiluminescence Detection
Authors: Fanjul Bolado Pablo , Pereira Silva Neves Marta Maria , González García María Begoña , Hernández Santos David
Published: February 2020

In this work a miniaturized flow injection analysis (FIA) system coupled with optical detection for carrying out electrochemiluminescence (ECL) based assays is presented.

Screen-printed electrodes integrated in one channel flow-cell (TLFCL, Thin layer flow-cell) were used as the electrodic surface. In these electrodes a transparent slide, that usefully allows the detection of air bubbles inside the cell, is attached over the screen-printed electrodes platform delimiting a flow channel (height 400 μm; volume 100μL). The injection is done through an “in-line luer injection port” where sample volume can be easily controlled by operator through a precise syringe. This configuration brings important advantages since it simplifies operability and effectiveness of working in FIA systems. TLFCL working electrodes were modified with different nanomaterials in order to carry-out innovative ECL based proofs-of-concept. By combining the bipotentiostat/galvanostat and the UV-VIS spectrometer of SPELEC device, the ECL signal was simultaneously (electrochemically) generated and captured (with the aid of a reflection probe connected to the spectrometer).

The ECL behaviour of the developed electro-generated luminescent assays was carefully evaluated assessing aspects as sensitivity, limits of detection and reproducibility and the analytical figures of merit were obtained. Moreover, 3D dynamic ECL plots were registered for the acquisition of real-time luminescent spectrum, relating wavelength emission, potential, and ECL signal in a 3D perspective.

Acknowledgements

MB González-García work was supported by Torres Quevedo grant (PTQ-13-05994) of the National Program for the Promotion of Talent and Its Employability of the Spanish Ministry of Economy and Competitiveness.
(Invited) Substance Release Triggered By Biomolecular Signals in Bioelectronic Systems
Authors: Katz Evgeny
Published: February 2020

A new approach to bioelectronic Sense-and-Act systems was developed with the use of modified electrodes performing biosensing and substance-releasing functions. The sensing electrode was activated by biomolecular/biological signals ranging from small biomolecules to proteins and bacterial cells. The activated biosensing electrode generated reductive potential and current, which stimulated dissolution of an Fe3+-cross-linked alginate matrix on the second connected electrode resulting in the release of loaded biochemical species with different functionalities. Drug-mimicking species, antibacterial drugs and enzymes activating a biofuel cell were released and tested for various biomedical and biotechnological applications. The studied systems offer great versatility for future applications in controlled drug release and personalized medicine. Their future applications in implantable devices with autonomous operation are proposed.
Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid By a Novel Electrochemical Sensor Based on N2/ Ar RF Plasma Assisted Graphene Nanosheet/Graphene Nanoribbon
Authors: Jothi Lavanya , S Neogi , Nageswaran Gomathi
Published: February 2020

A highly selective electrochemical method was developed for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) using a glassy carbon electrode modified by radio frequency nitrogen/ argon plasma (N2/Ar) mediated graphene sheets / graphene ribbons (GS/GR).The performance of the electrode towards was investigated by cyclic voltammetry, different pulse voltammetry (DPV) and chronoamperometry. The excellent electrocatalytic activity toward the oxidation of AA, DA and UA was demonstrated with a well-separated voltammetric peaks between AA/DA, DA/UA and AA/UA are 220,150 and 372 mV (vs. Ag/AgCl) in DPV, respectively. The detection limits (S/N = 3) of 0.00053 µM, 0.00025 µM, 0.00057µM were obtained for AA, DA and UA in PBS, respectively. Due to the synergistic effect between the high conductivity of graphene hybrid and the catalytic activity of N2, the as-prepared composite showed excellent performance. Additionally, the N2/Ar/GS/GR/GCE electrode presented well anti-interference ability, stability and reproducibility.
Low-Overhead Thin-Film Approaches and Platforms for Spectroscopic Fingerprinting and Electronic Single-Molecule Sensing
Authors: Karawdeniya Buddini Iroshika , Bandara Y. M. Nuwan D. Y. , Whelan Julie C. , Nichols Jonathan W. , Dwyer Jason R.
Published: February 2020

Nanopores are nanochannels formed through thin insulating membranes such as silicon nitride, and are powerful, yet conceptually and structurally simple, single-molecule sensor elements. When immersed in an electrolyte and with a cross-membrane applied voltage, the presence of a target species is indicated, in a resistive-pulse-sensing mode, by a perturbation of the ionic current through the pore whose frequency is correlated to the analyte concentration, and whose characteristics relate to the analyte, solution, and nanopore properties. It is important to be able to tune the nanopore size and surface properties; we present low-overhead routes based on electroless plating to fabricated customized nanopores. Those fabrication strategies can augment the performance capabilities of channel-through-membrane devices, but are also useful in combination with other structures and applications. In particular, we have used the same core electroless plating approach to turn a wide variety of materials into substrates for surface-enhanced Raman spectroscopy (SERS). These materials span from conventional micro- and nanofabrication-compatible materials, whether native or highly structured, to consumer-scale materials such as paper. These materials can, by their properties and construction, offer chemical analysis capabilities that complement the added SERS performance. In the case of paper-based SERS, an added benefit is the natural compatibility with the demands of low-cost diagnostics, including ease of disposability. Details of nanofabrication strategies will provide context for discussion of prospects of, and concrete biosensing applications using, tailored nanopore single-molecule sensors and multifunctional SERS substrates. Practical issues affecting device ease of use and sensing performance will be outlined, extending to disposable devices.
High Volume Zero Power Low Cost PPB Level Printed Nano-Sensors for Iot
Authors: Stetter Joseph R , Carter Michael T
Published: February 2020

The sensing capabilities of Carbon nanotubes [CNTs] are often reported in the literature [1,2] but we describe here a commercial sensor based on an amperometric detection method using CNT electrodes. The commercial availability means that it has been thoroughly vetted not only for sensitivity, but also for practical response time, selectivity, and stability in T, P, RH and time dimensions. The CNT-composite electrodes are robust, and while not as inert as the sp4 diamond, they exhibit chemical stability >sp3 carbons. The significant advantage is the extremely high surface area with virtually every atom a surface atom and therefore high catalytic activity at low loadings. These characteristics are important in high volume sensors so that small size and low cost are enabled along with the inherent low power of electrochemical sensors. This combination of characteristics along with the practical manufacturing by using printed electronics approaches is our key to bridge the cost-performance gap and penetrate into high volume consumer and environmental markets with these sensors. The first two environmental gases that use the nano-catalyst electrodes are NO2 and O3 in air at ppb levels. 

In order to address global problems with sensors, we know that we will need millions to billions of sensors. This implies a low cost and a sensor design amenable to high volume production. The solution to the World Health Organization’s recognized air quality crisis is accelerated by a global air quality network and this network will need Ozone and nitrogen dioxide sensors as these are lung irritants produced by anthropogenic activity. Business models for the practicality of trillions of connected devices and sensors are emerging in the IoT. Our manufacturing process for the nano-catalyst electrodes involves screen printing for low cost and high volume and it combines the best practices of the semiconductor microfabrication industry with the speed and low cost of the Printed Electronics revolution. This approach can meet the needs for new high volume low cost sensors and accelerate our fight against climate change. Many more sensor products and applications are expected as crowd-sourced pollution measurements are enabled and IoT connected devices allow instant communication of vital information.

1] J. R. Stetter and G. J, Maclay, “Carbon Nanotubes and Sensors: A Review,” in Advanced Micro and Nano Systems, Volume I, Chapter 10, Baltes et al., eds. Wiley-VCH Verlag-GmbH and Co., Weinheim, Germany, pp357-382, 2004 ISBN 3-527 30746-X, [Invited].

2] A. Star, T-R.Han, V. Joshi, and J.R. Stetter, “Sensing with Coated Carbon Nanotube Field Effect Transistors,” Electroanalysis 2004, 16 (1-2), 108-112.
Surface Plasmon Immunoarrays for Non-Glucose Diabetes Biomarkers
Authors: Krishnan Sadagopan , Singh Vini , Patel Manoj Kumar , Niroula Jinesh
Published: February 2020

Diabetes is a very complex, chronic immune disorder that requires extensive medical care with multifactorial risk-reduction strategies beyond glycemic control. In recent years, the prevalence of diabetes, in particular, type 1 diabetes (T1D), has significantly increased from 5% to 10%, and this has in turn has impacted the incidence of associated lethal complications in children and adults. Personalized glucometers allow diabetes management by easy monitoring of the high millimolar blood-glucose concentration levels. However, the importance of non-glucose based diabetes biomarkers has recently gained considerable attention for early prediction and providing insights about the diabetes metabolic pathways and understanding diabetic disorders. Nevertheless, non-glucose markers of diabetes are present at much lower concentrations (picomolar to femtomolar) than the glucose levels in blood. High abundances of interfering components such as cell lysates and serum proteins (matrix effect) in clinical matrices affect reliable detection and sensitivity. Hence, detection of biomarker levels in complex clinical matrices compared to simple buffer solutions poses a considerable challenge in assay development and validation. Herein we present results from our surface plasmon resonance immunoarrays for measurements of ultra-low levels of non-glucose based diabetes markers present in serum and whole blood.

Acknowledgements: This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.
Glycated Albumin Detection Using Electrochemical Aptasensor for Screening and Monitoring of Diabetes Mellitus
Authors: Bunyarataphan Sasinee , Maruset Lalita , Paiboonsukwong Kittiphong , Fucharoen Suthat , Dharakul Tararaj , Japrung Deanpen
Published: February 2020

A simple electrochemical aptasensor was developed for the detection of glycated albumin (GHSA) using ssDNA aptamer that selectively binds to GHSA as a recognition element. The biotinylated ssDNA aptamer was immobilized on a streptavidin-modified screen-printed carbon electrode (SPCE). The changes of interfacial features of the electrode surface, which were based on the aptamer-GHSA interaction, were probed in the presence of the redox Fe(CN)6
3- using square wave voltammetry (SWV) measurements (Fig 1). The results showed that limit of detection of our sensor was 3 µg/ml, with a calibration curve to the range of 16 mg/ml. The aptasensor showed high selectivity for GHSA over other molecules that is usually available in the blood. Our aptasensor was successfully applied to detect GHSA in serum samples, which demonstrated the higher levels of GHSA concentrations in diabetes than normal persons. These indicate that our electrochemical aptasensor has a potential for diagnosis and monitoring of diabetes mellitus.

Figure 1
In Operando Measurement of Lithium Polysulfides in Lithium-Sulfur Batteries Using Attenuated Total Reflection Spectroscopy
Authors: Saqib Najmus , Ohlhausen Gretchen M , Porter Jason Morgan
Published: February 2020

Li-S cells promise a theoretical capacity much greater than existing Li-ion technology, but the problem of polysulfide shuttling, which leads to self-discharge and loss of active material, remains one of the largest barriers to commercial adoption. We report a spectro-electrochemical cell designed for in operando measurements of the order and concentration of lithium polysulfides (Li2Sn, where n is the order). The design is a major improvement on existing cells, which typically require significant modifications from commercial cell geometries and require low charge/discharge rates during operation. The optically accessible Li-S cell resembles a CR2032 battery, and is constructed on a metallic disc with a diamond crystal at its center.

Attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy is used for in-operando measurements of soluble polysulfides, which are present in the electrolyte-saturated pores of the sulfur electrode. The diagnostic was calibrated using ATR spectra of lithium polysulfide standards, prepared from direct reaction of lithium sulfide and sulfur. The order and concentration of lithium polysulfides in a sample are determined from the position and area of a characteristic IR absorption band. The diagnostic routine can measure polysulfide order and concentration to within 5% and 0.1 M, respectively. Polysulfides smaller than Li2S4 are insoluble and are not present in ATR spectra.

Li-S cells were discharged at C rates up to 2 with simultaneous measurement of lithium polysulfide order and concentration. The obtained voltage profiles are consistent with those reported in literature. During discharge, polysulfide order steadily decreases while polysulfide concentration initially increases followed by a steady decrease. The initial increase in concentration is attributed to: i) reduction from elemental sulfur to Li2S8, and ii) reduction of Li2S8 to smaller polysulfides. The subsequent decrease in concentration is attributed to formation of insoluble polysulfides, which are not measured by the diagnostic. Charging the cell follows the opposite trend, except that elemental sulfur is not recovered.
Carbon Structure Originated Chirality in Carbon Nanotubes
Authors: Harutyunyan Avetik R , Pierce Neal , Chen Gugang
Published: February 2020

The origin of single wall carbon nanotube chirality includes fundamental understanding on formation mechanism of tubular carbon topology and its interrelations with catalyst features. Elucidation of this mechanism is key for realizing untapped potentials of nanotubes, because nanotube chirality governs its physical properties. For more than two decades studies have revealed the essential contributions of a catalyst features (diameter, morphology, composition and structure) in chirality abundance of grown nanotubes. Thus, chirality origination by catalyst structure via an epitaxial relationship emerges as a dominant mechanism. However, it is easy to overlook the hypothesis that was speculated in early stages of nanotube discovery in which chirality originates from hemispherical fullerene end-cap. To address this long standing dispute, our strategy was to decouple grown carbon structure properties from the impact of catalyst features. To this end, we grew carbon nanotubes on liquid catalyst with isotropic surface and thereby eliminated the entire complex catalyst feature’s contributions mentioned above. We found that the tubes with chirality (11,1)/χ=4.31o grown on isotropic surface of catalyst, can be up to eightfold preferable than tubes with larger helix angle (9,4)/χ=17.48o, although having exactly same diameter d=9.156Å. Abundances of tubes grown on solid polyhedral catalysts with certain structure and shape follow completely different patterns. This finding suggests chirality origination in carbon nanotubes as an intrinsic property of carbon structure. It distinguishes between the chirality origination by carbon structure and amendment by catalyst and could lead to the comprehensive theory of chirality formation. The role and energetics of carbon flux density and the type of elementary carbon building blocks (dimers, trimers, chains, clusters …) that form the precursor for carbon nanotube cap, and thereby originate the chirality will be discussed.
Photopotential and Polarization Characteristics of Ruthenizer Complex Sensitized TiO2 Electrode for Marine Microbial Fuel Cell
Authors: Nay Wunn Htoo , Motoda Shinichi , Morita Motoaki
Published: February 2020

We have been studied the performance of TiO2 electrode which is assembled in Marine Microbial Fuel Cell (MMFC). To increase the performance of TiO2 electrode and to improve conversion efficiency from solar energy, dye sensitizing was introduced to TiO2 electrode. The dye used for this experiment is a Ruthenizer complex, Di-tetrabutylammonium cis- bis (isothiocyanato) bis (2, 2-bipyridyl-4, 4’-dicarboxylato) ruthenium (II), well known as N719 dye, which shows high reproducibility and stability performance in dye-sensitized solar cells (DSSC). We also tried forming of Hydroxyapatite (HAp) layer on TiO2 surface before dye sensitizing for the purpose of anchorage effect of dye on TiO2 surface. The measurement of photopotential and polarization property were carried out in the artificial seawater as an electrolyte which does not include the redox couple as a mediator.

Photopotential and polarization was measured with a standard calomel electrode (SCE) as a reference electrode under the irradiation of a 150 W Xenon Lamp, and a platinum electrode was used as a counter electrode for polarization curve. In the measurement of photopotential, the potential dropped to active direction when the light was turned on. Once it reached to the most active potential value, it went back to noble direction slightly for 5 to 15 minutes after the light was on. The change in photopotential after that duration became small and it tended to be stable for 2 hours. This behaviour of photopotential was similar in all measurement of test electrodes.

The amount of Ruthenizer after 2-hour measurement of photopotential became relatively smaller compared to that before measuring. This is because dye recombination with TiO2 electrons took place with artificial seawater electrolyte in the absence of a redox couple for dye regeneration. But, the photopotential of dye-sensitized TiO2 electrode with HAp layer showed more active than that without HAp. This showed good compatibility of HAp since it did not disturb the performance of photo-catalytic reaction of TiO2 and it may show the ion or electron selectivity between Ruthenizer and TiO2 phases. The polarization measurement showed no distinct effectiveness of Ruthenizer sensitizing on TiO2 surface other than suppressing the TiO2 photo-catalytic reaction.

As the results, Ruthenizer sensitizing on TiO2 electrode showed lower photo-catalytic effect by the recombination of oxidized Ruthenizer electron due to absence of a redox mediator. On the other hand, using HAp on TiO2 electrode for Ruthenizer sensitizing showed improvement in photopotential characteristics of TiO2 electrode.
Advanced Characterization of Molten Salts
Authors: Merwin Augustus , Benmore Chris , Williamson Mark A.
Published: February 2020

Standard methods of analysis are frequently incapable of characterizing molten salts due to the high temperatures and chemically reactive nature of these systems. As a result, fundamental properties of molten salt solutions, and material interactions with them, remain unknown despite their industrial significance. The molten LiCl, LiCl-Li2O, and LiCl-Li2O-Li systems are of specific interest to the electrolytic reduction process used to treat oxide nuclear fuels prior to pyrochemical reprocessing. In this study, we employ two advanced techniques, impedance sensitive electrochemistry and synchrotron based high energy X-ray diffraction (HEXRD), to characterize molten LiCl and to demonstrate the benefits of these methods of analysis.

Impedance dependent electroanalytical chemistry was used to study the electrochemical behavior of molten LiCl-Li2O, and to investigate the processes associated with Li+ reduction from the melt. During this study, a unique behavior of the AC signal was observed to coincide with Li+ reduction. This effect has been investigated in terms of the electrochemical reversibility of the Li|Li+ redox couple, and has yielded information that could not be obtained using standard DC voltammetry techniques. The advantages of employing impendence sensitive methods of electroanalysis for the study of molten salts over typical DC voltammetry methods will be discussed.

The nature of elemental Li suspended in molten LiCl has been the subject of research for more than 50 years without yielding conclusive results. The study of molten solutions containing Li is exceptionally challenging due to the reactivity of molten Li, and as a result requires advanced methods of analysis. In attempt to circumvent these challenges, a system has been developed for containing molten salts and liquid metals during synchrotron characterization at the Advanced Photon Source (APS). By employing the APS, the system is capable of in situ characterization of molten LiCl while electrochemically forming Li in the melt. Standard methods of synchrotron analysis are incapable of characterizing molten LiCl due to the low energy state of the electrons of interest (55 eV in the case of Li). HEXRD offers a distinct advantage in this regard, as it is capable of yielding the structure factor and the corresponding pair distribution function of low energy electron states using high energy X-rays. In the current experiment, 100 KeV X-rays were propagated through an atmospheric chamber, the melt containing crucible, and a molten LiCl electrochemical cell, in order to characterize the molten solution during electrochemical analysis. This apparatus enables the study of the physical chemistry of the melt, as well as in situ characterization of material interactions with the high temperature fluid. The ability of this technique to characterize molten LiCl-Li2O-Li at 650°C will be presented along with an analysis of the chemistry of the melt itself.
Implications of Measurement Uncertainty in Battery Performance Analysis
Authors: Nagpure Shrikant C , Dufek Eric J. , Dickerson Charles C , Bewley Randy L , Walker Lee K. , Wood Sean M , Liaw Bor Yann , Tanim Tanvir
Published: February 2020

Laboratory testing of coin cells, batteries, battery packs and modules is essential in development of durable, reliable and safe battery systems. Battery testing hardware and software have improved significantly over the past decade, but the effectiveness of the laboratory test results from advanced battery testing equipment depends on its accuracy and precision. Battery testing hardware is capable of measuring only primary parameters such as current, voltage and time during testing. Hence any uncertainty or error in measuring these primary parameters will result in loss of accuracy and precision in subsequent analyses and erroneous prediction of battery performance [1, 2].

Analysis of battery systems goes beyond the scope of the primary parameters, however, and depends largely on the derived critical secondary performance parameters such as capacity, energy, power, and Coulombic efficiency. Moreover, for advanced failure mode analysis diagnostic and prognostic tools such as differential capacity and state of charge estimation are used. The battery degradation mechanisms and failure modes can be quantified from differential capacity analysis by evaluating loss of active material, loss of lithium inventory, and change in reaction kinetics [3]. State of charge (SOC) is another critical parameter that defines the performance state of the battery. Uncertainty in SOC estimation limits battery usage during operation [4]. Combined SOC and differential capacity analyses depend on the calculation of parameters such as capacity which in turn depend on accurate and precise primary parameter measurements.

This work addresses an approach to estimate uncertainty in primary measured parameters. Equations to identify uncertainty in derived complex parameters will be discussed. A quantitative analysis of uncertainty in critical analysis and performance parameters will be presented. The results show how errors propagate from the primary measurements to the more advanced diagnostic and prognostic methods as well as the subsequent effects on performance analysis of battery systems.

References:

[1] John L. Morrison, Gary L. Hunt, Donna J. Marts, and Chester G. Motloch, “Uncertainty Study INEEL EST Laboratory Battery Testing Systems, Vol 2: Applications of Results to INEEL Testers,” INEL/EXT-01-00505, Idaho National Laboratory (2003)

[2] Barry N. Taylor and Chris E. Kuyatt, “Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results,” NIST Technical Note, 1297 (1994)

[3] Matthieu Dubarry, Arnaud Devie, and Bor Yann Liaw, “
The Value of Battery Diagnostics and Prognostics,”J. Energy Power Sources, 1, 242 (2014).

Zhe Li, Jun Huang, Bor Yann Liaw and Jianbo Zhang, “On State-of-Charge Determination for Lithium-ion Batteries,” J Power Sources, 348, 281, (2017)
(Invited) Measurement Methods to Quantify the Physico-Chemical Parameters Required for Lithium Ion Battery Performance Models
Authors: Landesfeind Johannes , Ehrl Andreas , Morasch Robert , Wall Wolfgang A. , Gasteiger Hubert A.
Published: February 2020

Numerical simulations based on the porous electrode theory [1] are commonly used to describe and predict the rate performance of lithium ion batteries. This, however, requires that the relevant properties of the electrolyte and the porous electrode are available for a given electrolyte as a function of electrolyte composition (solvents, salt concentration) and temperature.

Unfortunately, very few of these parameter sets for typically used binary electrolytes can be found in the literature (e.g., Reference [2]), with the exception of the electrolyte conductivity, which can be determined quite easily. Therefore, over the past years, we have focused on developing methods to quantify the following parameters needed for numerical models: i) the thermodynamic factor (1+dln(f

±
)/dln(c)) [3], which is derived from the mean molar activity coefficient f

±
; ii) the effective ionic conductivity of porous electrodes by means of AC impedance spectroscopy [4]; iii) the binary diffusion coefficient, D

±
; and, iv) the lithium ion transference number, t+
[6].

In this contribution we will present the various measurement methods, compare the resulting parameters with the literature, and also present the temperature dependence of the thermodynamic and transport parameters.

 

References

[1] J. Newman, K. E. Thomas-Alyea, Electrochemical Systems, 3rded. (2004), Wiley-Interscience, Hoboken.

[2] L.O. Valøen, J. N. Reimers, J. Electrochem. Soc. 152(2005) A882.

[3] J. Landesfeind, A. Ehrl, M. Graf, W. A. Wall, H. A. Gasteiger, J. Electrochem. Soc. 163(2016) A1254.

[4] J. Landesfeind, J. Hattendorff, A. Ehrl, W. A. Wall, H. A. Gasteiger, J. Electrochem. Soc. 163(2016) A1373.

[5] A. Ehrl, J. Landesfeind, W. A. Wall, H. A. Gasteiger, J. Electrochem. Soc. 164(2017) A826.

[6] A. Ehrl, J. Landesfeind, W. A. Wall, H. A. Gasteiger, submitted.

 

Acknowledgements

We gratefully acknowledge the funding by the Bavarian Ministry of Economic Affairs and Media, Energy, and Technology for its financial support under the auspices of the EEBatt project as well as funding by the German Ministry for Education and Research in the framework of the project ExZellTUM II (funding number 03XP0081).
(Invited) NMR Studies of SEI Coatings on Silicon
Authors: Jin Yanting , Kneusels Nis-Juliens , Marbella Lauren , Kim Gunwoo , Castillo-Martínez Elizabeth , Magusin Pieter C.M.M , Grey Clare P.
Published: February 2020

The use of a wide variety of NMR spectroscopy techniques to characterise the SEI that is formed on silicon on cycling will be described. We have synthesized 13C enriched forms of additives such as FEC, which have allowed detailed structural studies to be performed. The results have been compared to the species identified in prior work on products formed on reducing FEC with lithium naphthalenide.1 Dynamic nuclear polarization approaches allow two dimensional experiments to be performed in reasonable timeframes helping to assign the different species observed in the 13C and 1H NMR spectroscopy. Studies of coated silicon samples will be presented.

Michan, A. L.; Parimalam, B. S.; Leskes, M.; Kerber, R. N.; Yoon, T.; Grey, C. P.; Lucht, B. L. “Fluoroethylene Carbonate and Vinylene Carbonate Reduction: Understanding Lithium-Ion Battery Electrolyte Additives and Solid Electrolyte Interphase Formation” Chem. Mater., 2016, 28, 8149.
Characterization of Lithium Inventory in Lithium Metal Anodes during Cycling
Authors: Raj Abhishek , Park Jeung Hun , Steingart Daniel A
Published: February 2020

A rising interest in batteries has resulted from a need for improved energy storage systems for transportation and portable electronics applications. Lithium is of particular interest as an anode due to its low redox potential and high specific capacity. However, these systems have not been practically realized due to the nonuniform plating of lithium. Many studies have modeled this formation of dendritic or mossy structures as a function of parameters such as temperature, electrolyte composition, current density and overpotentials [1]. However, the majority of these efforts have focused on the influence of these parameters on the nucleation and growth of lithium at early stages; the processes for deplating of lithium during discharge and the continued growth of dendritic structures, once formed, are poorly understood.   In this work, we use commercially available primary cells as a basis for understanding the movement of lithium during cycling. Specifically, we discharge both coin and pouch cells at a range of C rates to specified states of charge (SOC). During discharge, acoustic time of flight studies are used to provide insight on how mass is transferred between layers [2]. Once the cell has been discharged to the specified SOC, electrochemical impedance spectroscopy is conducted before dismantling the cell and observing the lithium electrode using scanning electron microscopy. The same characterization methods are subsequently used for cells that have been discharged and charged for a range of cycles. Through these techniques, we track how lithium is transferred between electrodes, as well as how lithium is spatially utilized across the anode.     References   [1] Xu, Wu, Jiulin Wang, Fei Ding, Xilin Chen, Eduard Nasybulin, Yaohui Zhang, and Ji-Guang Zhang. 2014. “Lithium Metal Anodes for Rechargeable Batteries.” Energy & Environmental Science 7 (2). The Royal Society of Chemistry: 513–37. [2] Hsieh, A. G., S. Bhadra, B. J. Hertzberg, P. J. Gjeltema, A. Goy, J. W. Fleischer, and D. A. Steingart. 2015. “Electrochemical-Acoustic Time of Flight: In Operando Correlation of Physical Dynamics with Battery Charge and Health.” Energy & Environmental Science 8 (5): 1569–77.
(Invited) Ion Transport through the Pore Channels of Anodic Nanoporous Alumina Membranes and Graphite Composite Electrodes
Authors: Abe Takeshi , Fukutsuka Tomokazu , Miyazaki Kohei , Miyahara Yuto
Published: February 2020

Present LIBs for EV-use possess large power densities by the sacrifice of energy densities in order to shorten the charging time. In the practical LIBs for portable devices, dense and thick composite electrodes are used. In this case, the ion transport of electrolyte solution through the pores in the composite electrodes becomes a slow process. In order to enhance the energy densities with remaining high power densities, the ion transport rate should be increased for the dense and thick composite electrodes. Unfortunately, to develop dense and thick electrodes with high power densities, fundamental understanding of the ion transport in composite electrodes has not been clear. In this study, ion transportation behavior was investigated with ac impedance spectroscopy.

To focus on the impedance of ion transportation of electrolyte through the pores in composite electrode, we prepared anodic aluminum membranes with homogeneous macro- and meso- pores. In addition, graphite composite electrodes were also used. As a result, we obtained semi-circles, and this semi-circle was assigned to the ion transport process through the graphite composite electrode. The detail analysis will be presented at the meeting.
(Invited) High Lithium Sulfide-Loading Electrode for Practical Li/S Cells
Authors: Cairns Elton J. , Sun Dan
Published: February 2020

The development of the Li-ion battery (LIB) has led to a portable electronics revolution during last couple of decades, however, the traditional LIB seems to be insufficient for practical application in some emerging markets due to the limited specific energy of the cell. For mass market conversion to electric vehicles, high specific energy (> 300 Wh kg-1) rechargeable battery systems of low-cost for energy storage are required. Among all alternatives, the lithium/sulfur cell has been considered most promising due to its low cost, high abundance, ultrahigh theoretical specific energy (2,566 Wh kg-1) and theoretical energy density (4,260 Wh L-1) which far exceed those of conventional lithium-ion cells. Nevertheless, after extensive study of both sulfur cathodes and lithium sulfide cathodes, neither of these technologies has been commercialized due to poor long-term cycle life and low demonstrated specific energy of lithium/sulfur cells. Practical applications require high sulfur loading electrodes together with the lowest “dead weight” possible in the cell while maintaining good performance. This is quite challenging because commercial current collectors have mechanical limitations in electrode loading and sulfur utiliation. Due to the insulating nature of S and Li2S, the addition of a significant amount of a conductive additive into the high loading electrodes is required and introduces more surface area, and thus more electrolyte is needed which further leads to more dead weight. Recently, lithium sulfide was proposed to be a more desirable electrode material because it permits the cell to be assembled in discharged state and avoids problems associated with volume expansion of sulfur during discharge. Disadvantages of lithium sulfide include challenging issues due to its sensitivity toward moisture and solubility in many organic solvents. In order to achieve high specific energy, we have developed a novel Li2S/KB@Cf electrode (Li2S content: 74 %,) using a robust 3-dimensional (3-D) current collector with a high Li2S loading up to 11.29 mg cm-2 (S loading: 7.85 mg cm-2), which can deliver an areal capacity of 7 mAh cm-2 after 50 cycles with an Electrolyte/Sulfur ratio of 5.5 (see Fig. 1). We will present our recent progress in high S loading cells and more detailed information about active material development, electrode composition and modifications of the electrolyte and cell configuration.

Figure 1
(Invited) Pulsed Electrodeposition of Refractory Metals in Ionic Liquids
Authors: Ispas Adriana , Endrikat Anna , Engemann Thomas , Peipmann Ralf , Bund Andreas
Published: February 2020

This paper presents recent results from authors’ lab on the pulsed electrodeposition of refractory metals from ionic liquids (ILs). Special focus will be given to the refractory metals tantalum and niobium (Fig. 1) as they are promising candidates for surface finishings with extremely high corrosion resistance.

We could show that by varying the pulse plating parameters (such as the potential of the on pulse, as well as the frequency and the duty cycle) one can optimize the morphology of the deposits. Thus, experimental conditions have been identified with which uniform and crack-free deposits can be obtained. Due to the high viscosity and low conductivity of the ionic liquids, the useful frequency range for pulse plating is somewhat different from one knows from aqueous electrolytes. Moreover, the effect of the temperature (from 25°C till 170°C) on the properties of the deposits has also been investigated and will be discussed in this paper.

Fig. 1. Nb layer electrodeposited on Ti substrates from 0.5M NbF5 in 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide at RT; Deposition conditions: 1 min @-1V; 1 min @ -2.5V, sequence repeated for 2500x.

Figure 1
(Invited) Low Wear Index Chromium Coatings Electroplated from a Functional Reach-Compliant Trivalent Chromium Chemistry
Authors: Hall Timothy D , Taylor E. J. , Inman Maria , Snyder Stephen , Xu Jing , Radhakrishnan Rajeswaran
Published: February 2020

Faraday Technology Inc. is a research, development and engineering firm developing electrochemical innovations based has pulse/pulse reverse electrolytic principles [1]. One of Faraday’s current activities is directed towards the development of an innovative REACH-compliant plating process for deposition of functional chrome coatings, based on replacement of the conventional hexavalent chromium plating chemistry with a non-toxic trivalent chromium chemistry. Hexavalent chromium plating has been used for many decades to produce hard, durable coatings with excellent wear and corrosion resistance properties. However, hexavalent chromium has come under increasing scrutiny due to the toxic nature of the bath, effects on the environment, and workers’ health. Faraday has demonstrated that the chrome coatings prepared using the FARADAYIC(R) Process in a trivalent chromium chemistry have equivalent functional properties to chrome coatings produced with a hexavalent chromium bath. The data demonstrates equivalent or superior: 1) plating rate, 2) Knoop hardness, 3) current efficiency, 4) hydrogen embrittlement behavior, 5) adhesion, 6) corrosion resistance, 7) porosity, 8) thickness, 9) Taber Abrasion, Ball on Flat Reciprocating and Dithering wear resistance, with no hexavalent chromium formation in the bath.

This paper will discuss the 2013 EPA Green Chemistry Challenge Award winning work on the development of a REACH-compliant plating process for wear resistant, functional coatings from a single, simple-to-control trivalent-based electrolyte. Specifically, this paper will discuss electrochemical deposition approaches to improve (decrease) the wear index of the chrome coating, to meet the performance from conventional chrome coating processes.

Acknowledgements: This study is supported by the US Army (W911NF-11-2-0014) and private sources.

[1] E. J. Taylor “Adventures in Pulse/Pulse Reverse Electrolytic Processes: Explorations and Applications in Surface Finishing” J. Applied Surface Finsihing,
3(4), 178-189 (2008).
A High Performing Zero Gap Alkaline Electrolyzer
Authors: Masel Rich , Liu Zengcai , Yang Hongzhou , Sajjad Syed D. , Gao Yan , Kaczur Jerry J.
Published: February 2020

Water electrolyzers are being developed as a way of storing renewable energy, as a way to produce hydrogen for fuel cell automobiles, and as a route to renewable fuels and chemicals. In this paper, we demonstrate alkaline water electrolyzers at 60 °C with iron/nickel/cobalt catalysts that show 1 A/cm² at a 1.9 V cell potential The performance is stable for 2000 hours, showing only 3-5 µV/hr degradation. Key to the findings is the development of new Sustainion™ alkaline exchange membranes that show high conductivity and stability in 1 M KOH.

The paper will discuss new developments that improve the response of the electrolyzers to process upsets, and to improve the on-off performance of the devices.