bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Application of High Hydrostatic Pressure and Nanofilms to the Fabrication of Enzyme Biosensors
Authors: Reyes De Corcuera Jose I , Yang Daoyuan , Jackson Janeal
Published: February 2020

Fabrication of enzyme biosensors has evolved since they were first conceived in the late 1950s. Increased sensitivity and reproducibility have been perhaps the two main driving forces for the development of such sensors. Increased sensitivity enables miniaturization and the development of implantable sensors for in-vivo applications. Because most oxidoreductases used in the fabrication of enzyme biosensors quickly lose their activity over time, most enzyme biosensors either are one-use disposable strips or require periodic change of membrane and frequent calibration, which makes them impractical for industrial applications. With the nanotechnology boom, several research reports have focused on increased sensitivity by creating porous nanostructures. There are also several reports on the effects of immobilization, cross-linking, and additions of solutes to stabilize enzymes and extend the operational life of enzyme biosensors. Here we summarize our research for the last 10 years on the effects of platinization conditions, including the use of high hydrostatic pressure (HHP) up to 500 MPa on the fabrication of microporous platinum black structures that maximize electrode sensitivity. In our early research we reported a 60-fold increase in sensitivity of glucose biosensors. We also report the effect of enzyme entrapment in poly-o-phenylenediamine (PoPD) nanofilms and their impact on electrode sensitivity and stability on glucose oxidase, alcohol oxidase, and galactose oxidase. High pressure and immobilization in PoPD resulted in two orders of magnitude increase in glucose oxidase biosensors. In contrast, while HHP increased the stability of AOx by a factor of ~15, immobilization only increased its stability by a factor of ~5 stability and combined HHP and immobilization only increased the stability by a factor of 6.4 relative to the enzyme in solution.
Conducting Polymer-Based and Electrically Controlled Skin Mapping for Dermatological Diagnostics and Wound Healing Treatment
Authors: Fu Xiaoxu , Ahamed Ashiq , Cheong Yi Heng , Lisak Grzegorz
Published: February 2020

Novel approach of skin mapping technology was developed and optimized through controlled electrodeposition of conducting polymers (CPs). The CP has excellent flexibility, adequate conductivity and results in a high-resolution pattern of the skin surface. The formed CP pattern entity has distinct 3D structure, which is mirror reflection of target skin surface topology. Ex-situ (off-body) and in-situ (on-body) skin mapping methods were applied (Figure 1) [1], which were done via electropolymerization on a previously sampled skin stamp pattern or directly on the skin surface, respectively. Various 3D entity models of skin patterns, including scars, joint wrinkles, fingerprints and palm of a hand, were successfully developed for the intention to be used in dermatological applications, such as diagnosis, electrostimulation and controlled release of drugs to the pathological skin areas, such as wounds and scars.

This skin mapping approach was proved to have high universality. Skin leaves, in form of sebum, an insulating mark on substrate surface that it is in contact with. Furthermore, if that substrate is electrically conducting, the localized electropolymerization of the CPs in the presence of the insulating pattern (bare conducting metal and insulating mark deposition) resulted in the clear visualization of the skin surface outline (increased contrast between dark CP and unoccupied deposited insulating mark). Pt and Au coated polyethylene terephthalate (PET) films were used as conducting substrate, which provide excellent flexibility, conductivity and smooth surface.

To summarize, this novel conducting polymer-based and electrically controlled skin mapping approach is able to remodel various skin surface patterns and reflect micron-scale 3D structure, which is highly valuable for dermatological diagnostics (Figure 2). The capability of doping and controlled-releasing ions make it even more promising targeted materials for wound care applications.

References

[1] X. Fu, W. Zeng, A.C. Ramírez-Pérez, G. Lisak, 3-D and electrically conducting functional skin mapping for biomedical applications, Chem Commun 54(8) (2018) 980-983.

Figure 1
3D-Printed Hydrogel Capsule for Transporting Particles in Flow Channel
Authors: Nezu Kyosuke , Makino Masato , Takamatsu Kyuichiro , Kawakami Masaru , Furukawa Hidemitsu
Published: February 2020

Droplet based microfluidics is used for cell culturing, protein crystallization, drug delivery and mixture chemical reagent. It enables quick and accurate analysis with a small amount of reagent. Usually, droplets containing particles are made by T-junction using organic phase and water phase. Sometimes researchers want to replace medium, recovery and reseal particles in droplets. However it is difficult due to surface tension and difficulty to process hydrogel. It has been a problem for many years. In addition, there is a need for a capsule having a function of carrying and releasing drugs and cells to an arbitrary position. We propose 3D-printed hydrogel capsule to solve these problems. We made 3D-printed hydrogel capsule with particles entrance. The entrance is closed by bubble. N-isopropylacrylamide (NIPA) gel was selected. It was prepared for 3D-printing. NIPA gel is famous for phase transition. It swells below 32.6℃ and shrinks above that. With this principle, we can transport particle to remove rid bubble at any place. The 3D-printer we used was ACCULAS BA-30H (DMEC). Evaluate systems were made up of microscopic, syringe pump and flow channel. Flow channel was made of Polydimethylsiloxane (PDMS) using 3D-printed mold.
Electrochemical Sensor of Gas Phase Iodine
Authors: Perez Carlos R. , Klavetter Kyle Christopher , Coleman Jonathan Joseph , Siegal Michael P.
Published: February 2020

We report on a nanoelectrode array sensor for the detection of gaseous iodine at levels below 20 ppb within short exposure times. The sensor is constructed on a free-standing anodic aluminum oxide wafer with 120 nm diameter, 50 um length nanopores. On each wafer surface, continuous metal films are deposited: on one surface, a gold film is deposited such that it covers the nanopores, and, on the opposite surface, a platinum film is deposited such that the nanopores remain open and their volumes in contact with the environment. The gold film serves as the working electrode and the platinum film serves as the auxiliary and pseudo-reference electrode. The nanopores are filled with a pH 9 buffer aqueous solution to create an array of billions/cm2 electrochemical cells in parallel. Ionic conductivity is maintained for environments with relative humidity levels greater than ~30%. Here we report on sensor performance improvements that allow using this sensor in more arid environments, as well as in the presence of other relevant interferent analytes (e.g. Cl2).

The detection mechanism is the electrochemical oxidation of anionic species formed by the dissolution and subsequent hydrolysis of gas phase I2 in pH 9 buffer electrolyte. Gas phase I2 dissolves in the buffer following Henry's Law and then is hydrolyzed to several species, including the anionic species iodide and tri-iodide. The hydrolysis mechanism of I2 in the pH 9 buffer enables it to function as a concentrator for the anionic species. When the sensor is exposed to a gas stream containing iodine, continuous accumulation of the electrochemically detectable anionic species is possible, enabling preconcentration of the incoming flow-stream by several orders of magnitude.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Universal Brain-Machine Interfaces Enabled By Flexible Scalp Electronics and Deep Convolutional Neural Networks
Authors: Mahmood Musa Syed , Kim Yun-Soung , Herbert Robert , Yeo Woon-Hong
Published: February 2020

Electroencephalography (EEG) allows non-invasive monitoring of brain electrical activity at a fine temporal resolution. However, it is difficult to consistently capture high-quality biopotential signals due to natural variations in scalp and skin conditions. Conventional EEG systems suffer from inconsistent signal quality extensive preparation time, and uncomfortable and bulky electrode setups from long, inflexible wires and rigid electrodes. Improvements in analysis and machine learning techniques have allowed researchers to extract more information from EEG with fewer electrodes on the scalp with certain EEG paradigms. However, further hardware improvements would be required before these systems could be comfortably used daily. Here, we introduce skin-like hybrid electronics (SKINTRONICS), a fully portable, wireless, flexible biomonitoring electronics platform incorporating a soft elastomeric membrane for maximum conformability and wearability on the skin. This concept allows for a comfortable and ergonomic wearable BMI concept that can be used long-term without discomfort and is optimized for use in a rehabilitation setting for patients with brainstem injury or other motor impairment. Analytical and computational studies establish the fundamental design criteria of the SKINTRONICS, enabling seamless portable EEG recording with significantly enhanced signal quality over commercial systems. Analysis in the time domain and frequency domain are completed, with deep convolutional neural networks providing appreciable improvements over conventional techniques such as SVM. The real-time time-domain analysis with deep convolutional neural networks allows for highly accurate classification and fine machine control with high information transfer rates from only two channels. With six human subjects this wireless interface achieves a high accuracy (94.54% ± 0.90%) for a corresponding information transfer rate of 122.1 ± 3.53 bits per minute, demonstrated using a wireless wheelchair, motorized vehicle, and keyboard-less presentation using a two-channel EEG. This demonstrates great potential for this platform, which can accommodate a wide range of assistive technologies as well as different EEG paradigms like motor imagery (MI).
Electrochemical Signature of Peroxynitrite on Modified Boron-Doped Diamond Electrodes
Authors: Maher Shaimaa , Kalil Haitham , Bayachou Mekki
Published: February 2020

Endogenous and exogenous reactive oxygen and nitrogen species such as peroxynitrite have serious damaging effects on cell components and cell function. Peroxynitrite has emerged as a reactive species that is linked with oxidation and/or nitration of biomolecules. In biological context, peroxynitrite is the product of the combination between superoxide and nitric oxide radicals through a diffusion-limited reaction. The short lifespan and fast reactivity of peroxynitrite are adding more challenges to measure its concentration under physiologic conditions.

Although several methods have been established for peroxynitrite detection in aqueous solutions, they are still facing the problem of real-time quantification. In this paper, the electrochemical behavior of peroxynitrite has been studied boron-doped diamond electrodes (BDD). Recently, BDD have been successfully worked as platforms for electrochemical detection of various analytes in biological and environmental systems. BDD electrodes provide a wide potential window and a low background current that creates an excellent platform to fine-tune the surface for optimized detection of peroxynitrite.

In this research study, the direct electrochemical oxidation of peroxynitrite on modified BDD electrodes was recorded and investigated. A wide range of physicochemical characterizations were conducted to study the catalytic oxidation of peroxynitrite on modified BDD electrodes. The same modified BBD platform is used to develop a selective peroxynitrite sensor that can further be developed into a tool that can be used for both electrical stimulation and monitoring of peroxynitrite levels under physiologic conditions.
Electrochemical Detection and Determination of Various Bisphenol Compounds
Authors: Tom Robinson , Nelwood Michael , Soundappan Thiagarajan , Varman Arul Mozhy
Published: February 2020

Bisphenol compounds are well known compounds which are used to strengthen various plastic based materials. BP based plastic materials consumption (or) usage will result in type-II diabetes in the human being. This is because BP compounds are known as endocrine disruptors which will directly affect human metabolism. So far, all the BP contamination will be analyzed through standard analytical/chromatographic techniques like LC-MS etc. At the same time electrochemical detection of BP using appropriate electrochemical techniques is also comparable with the standard analytical techniques. Herein, we report the electrochemical detection of BP compounds based on modified/pretreated electrodes at the lab scale. We have detected and determined the various BP compounds in the physiological pH conditions using these electrodes. Further the sensitivity, selectivity, and linear range of these electrodes fall within the range to fabricate the sensors to detect BP contamination in the consumer applications, respectively.

Acknowledgment:

The research work presented herein is financially supported by USDA-NIFA

*Email:
tsoundappan@navajotech.edu
Polyimide-Based Electrodes for Electrochemical Water Splitting and N2 Reduction
Authors: Lin Yun-Xiao , Li Xin-Hao , Chen Jie-Sheng
Published: February 2020

Polyimide, a commercial organic polymer widely used as electronics coating, is found to have excellent electrochemical catalytic performance in water splitting and N2 fixation recently. Our exciting results are introduced as following two parts:

1.The exploitation of metal-free organic polymers as electrodes for water splitting reactions is limited by their presumably low activity and poor stability, especially for the oxygen evolution reaction (OER) under more critical conditions. Now, the thickness of a cheap and robust polymer, poly(p-phenylene pyromellitimide) (PPPI) was rationally engineered by an in situ polymerization method to make the metal-free polymer available for the first time as flexible, tailorable, efficient, and ultra-stable electrodes for water oxidation over a wide pH range. The PPPI electrode with an optimized thickness of about 200 nm provided a current density of 32.8 mA cm-2 at an overpotential of 510 mV in 0.1 mol L-1 KOH, which is even higher than that (31.5 mA cm-2) of commercial IrO2 OER catalyst. The PPPI electrodes are scalable and stable, maintaining 92% of its activity after a 48-h chronoamperometric stability test.

2.Production of ammonia is currently realized by the high pressure-high temperature Haber–Bosch process, while electrochemical N2 fixation under ambient conditions is recognized as a promising green substitution in the near future. Lack of efficient electrocatalysts for selective fixation and reduction of dinitrogen remains the primary hurdle for the initiation of potential electrocatalytic synthesis of ammonia. For cheaper metals, such as copper, limited progress has been made to date, as the process is theoretically considered not to be energetically feasible. In this work, we boost the N2 reduction reaction (NRR) catalytic activity of Cu nanoparticles, which originally exhibited negligible NRR activity, via a local electron depletion effect. The electron-deficient Cu nanoparticles are brought in a Schottky rectifying contact with a polyimide (PI) support which retards the hydrogen evolution reaction (HER) process in basic electrolytes and facilitates the N2 fixation to aﬀord the electrochemical NRR process under ambient aqueous conditions. This strategy of inducing electron deficiency provides new insight into the rational design of inexpensive NRR catalysts with high selectivity and activity.
Measurement of Macmullin Number for Different Electrochemical Fuel Cell Gas-Diffusion Media Using a Conductivity Cell Apparatus
Authors: Sepe Mitchell , Brizes Michael , Lopata Joseph Steven , Shimpalee Sirivatch , Weidner John W.
Published: February 2020

The objective of this study is to calculate the MacMullin Number (NM) of various Gas Diffusion Media to improve understanding of the transport through the Gas Diffusion Layer (GDL) for the Electrochemical Fuel Cell Model. In this model, GDL’s are used in the electrolyzer and the fuel cell itself. The outcome of this work will allow for different GDL’s to be compared to each other in a way that the best fit for the Fuel Cell Model can be determined. Experimental data obtained through the Conductivity Cell will allows for the NM to be calculated. The GDL materials used are activated carbon, nickel foam, and nickel mesh. Some samples have the addition of a microporous layer (MPL) to improve transport. A NM calculation allows for the samples with and with out the MPL to be compared. Once an average NM was found for each sample, the data was plotted and a trendline was fit. The trendline was used to compare NM calculation data to previous experimental data. The primary focus of the experiment is the comparison the porosity of the GDL samples verse the calculated MacMullin Number for each sample.

Figure 1 shows the Porosity of various GDL’s plotted against the calculated MacMullin Number. In this figure, GDL’s with an MPL and without an MPL were plotted and the trendline through the data was compared to the Bruggeman equation and the Toray equation. GDL’s containing a MPL tended to have higher NM then the other samples. This happens because the addition of the MPL increases the resistance of the sample. Figure 1 allows for the prediction of different GDL samples NM by using the calculated porosity.

References:

Martinez, Michael J., et al. Measurement of MacMullin Numbers for PEMFC Gas-Diffusion Media. Journal of The Electrochemical Society, 2008, Measurement of MacMullin Numbers for PEMFC Gas-Diffusion Media.

Shimpalee, Sirivatch, et al. Experimental Investigation and Numerical Determination of Custom Gas Diffusion Layers on PEMFC Performance. Elsevier B.V., 2016, Experimental Investigation and Numerical Determination of Custom Gas Diffusion Layers on PEMFC Performance

Martinez, Michael J., et al. Effect of Microporous Layer on MacMullin Number of Carbon Paper Gas Diffusion Layer. Elsevier B.V., 2012, Effect of Microporous Layer on MacMullin Number of Carbon Paper Gas Diffusion Layer.

Figure 1
Analyzing the Bandgap of 3D Perovskite Oxides: Machine Learning Approach
Authors: Kuramshin Robert , Allam Omar Adel , Jang Seung Soon
Published: February 2020

In this study we have developed a machine learning approach to analyze and predict the bandgaps of 1146 ABO3 perovskites, computed using density functional theory. Since DFT-computed bandgaps with high accuracy are normally also highly resource demanding, we developed a machine learning model to predict the perovskite bandgaps by utilizing readily available atomic and crystal descriptors. These descriptors include atomic electrochemical properties such as electron affinity and ionization energy of the A/B-site atoms, as well as Goldschmidt tolerance factor of the crystal structure. As we arrive at our results, we conduct a comparative study of two machine learning algorithms: namely kernel ridge regression and gradient boosting regression. Along the way, we employ recursive feature elimination and correlation based feature selection methods to remove the weakest inputs from our dataset, and reduce the 35 starting features down to 28 most essential features, resulting in a final model mean square error of 0.2 eV. Lastly, we performed a relative contribution analysis of the inputs with regards to their influence on the bandgap of the perovskites. In essence, we attempt to use machine learning as an analytical technique for evaluating the structure-bandgap relationship of perovskite.
Designing a Supramolecular Process for Post-STI CMP Cleaning
Authors: Graverson Carolyn F. , Zubi Tala B. , Keleher Jason J.
Published: February 2020

Chemical mechanical planarization (CMP) is a critical process step used in the fabrication of integrated circuits (ICs) and has ultimately led to the extension of Moore’s Law. Through a synergistic balance of a colloidal dispersion and mechanical downforce, excess topography is removed to achieve angstrom-level uniformity. Upon the completion of the CMP process, removal of unwanted particle residue/organic contaminants is achieved using oxidation/reduction reactions, etching, or encapsulation chemistry coupled with ultrasonic methods or polyvinyl alcohol (PVA) brush cleaning. The nature of the current cleaning techniques has been known to provide insufficient cleaning capacity for next generation devices. This work focuses on employing supramolecular chemistries as a means to improve overall post-STI CMP cleaning efficiency under low mechanical stress conditions, ultimately reducing defectivity. More specifically, the development of a supramolecular brush comprised of biomimetic polymers, such as β-cyclodextrin, was synthesized with excellent pore size tunability, which in turn is correlated to swellability, durability, and efficiency of particle removal.
Role of Molecular Structure on Controlling the Dynamic Equilibrium of the Ecosystem Present in Shallow Trench Isolation (STI) Chemical Mechanical Planarization (CMP) Slurry Formulations
Authors: Wortman-Otto Katherine M. , Graverson Carolyn F. , Saucedo Cynthia , Keleher Jason J.
Published: February 2020

Chemical Mechanical Planarization (CMP) has emerged as a critical process step for achieving angstrom-level uniformity in advanced integrated circuit manufacturing and has ultimately lead to the extension of Moore’s Law. This work specifically looks at Shallow Trench Isolation (STI) CMP, which is used in the electrical isolation of the active components in an integrated circuit by actively removing oxide overburden and stopping on Si3N4 to achieve global planarity and limit defectivity. This planarity is achieved through the synergistic balance of an applied mechanical force and the incorporation of a colloidal dispersion (slurry) containing ceria (CeO2) nanoparticles, rheology modifiers, and stability additives. In addition to the aforementioned additives, a main initiative of STI slurry formulation development has been centered around oxide rate control and selectivity enhancement. Current research has emphasized the addition of compounds that contain carboxylic acid, amine, and amino acid functionality. While the mechanism behind these additives is still of great debate, results have shown the importance of additive surface adsorption and nanoparticle surface redox properties. More specifically, in order to achieve optimal performance, the slurry additive must not impede the presence of surface oxygen vacancies on the nanoparticle, which are known to facilitate high oxide material removal rate (MRR). Slurry additives with redox activity as well as antioxidant properties show the highest MRR due to an increase in the surface oxygen vacancies and a decrease in the non-productive surface interactions. A suite of dynamic, analytical techniques such as atomic force microscopy (AFM), contact angle measurements, pre/post characterization of particle properties (size and zeta potential), coefficient of friction (COF), and UV-Vis spectroscopy, were employed. Results indicate a strong correlation between additive structure, slurry macro-environment, and overall CMP performance.
Characterization of Gas Diffusion Layers through Computational Fluid Dynamics Modeling and BET Theory
Authors: Brizes Michael , Sepe Mitchell , Satjaritanun Pongsarun , Shimpalee Sirivatch , Weidner John W.
Published: February 2020

The purpose of this work is to use computation fluid dynamics using mesh simulations to model the flow through gas diffusion layers (GDLs), in order to calculate the fundamental properties of the GDL. The study of porosity, tortuosity, liquid and gas permeability, and pore size distribution for GDL’s are the primary focus points in this work. The GDL model geometries seen in this investigation were obtained through three dimensional reconstructed micro-structures from micro X-ray computed tomography (CT). Figure 1 shows the microstructure and streamlines to model the movement of fluid through the GDL. The simulated GDL’s consist of: EP40T, Sigracet 25BA, Sigracet 25BC, GDS3250, and GDS3260.

The tortuosity calculated from simulations is taken at multiple points on the GDL to obtain an averaged value for the sample. The average value is used because the GDL structure is a matrix of random carbon fibers. The liquid and gas phase permeability is important to the calculation of tortuosity because it is a measure of the willingness of a porous media to flow through it. In addition, the simulated results are compared to experimental data through the calculation of the MacMullin number. The MacMullin number is a relationship defined by porosity divided by tortuosity. This number describes the ionic resistance, or resistance to current flow, through the GDL.

References:

Pal, M.K. Joyce, P.D. Fleming, A Simple Method for Calculation of the Permeability Coefficient of Porous Media, Tappi Journal. (2006).

Martínez Michael J., Shimpalee, S., Van Zee, J.W., 2009. Measurement of MacMullin Numbers for PEMFC Gas-Diffusion Media. Journal of The Electrochemical Society 156. doi:10.1149/1.3005564

Liu, S. Shin, S. Um, Comprehensive Statistical Analysis of Heterogeneous Transport Characteristics in Multifunctional Porous Gas Diffusion Layers Using Lattice Boltzmann Method for Fuel Cell Applications, Comprehensive Statistical Analysis of Heterogeneous Transport Characteristics in Multifunctional Porous Gas Diffusion Layers Using Lattice Boltzmann Method for Fuel Cell Applications. (2018).

Figure 1: Model geometry (EP40T) obtained from Micro X-ray CT with streamlines to show the flow.

Figure 1
Effects of Nitrogen-Doped Carbon Support on Oxygen Reduction Reaction Activity of Pt–Ni Nanoframe
Authors: Nakahoshiba Ryota , Li Tianchi , Ogura Kazuya , Kato Masaru , Yagi Ichizo
Published: February 2020

Polymer electrolyte fuel cells (PEFCs) are clean, sustainable devices and can produce electricity without the emission of CO2 gas. The oxygen reduction reaction (ORR) catalysts are required for the cathode in PEFCs because the ORR is sluggish. Pt shows the highest ORR activity in the metals. The ORR activity of Pt has been improved by alloying with 3d transition metals such as Ni,1) and Pt–Ni alloys have been used for the cathode in PEFCs. The ORR activity was also improved by using nitrogen-doped carbon (NC) as supports for PGM nanoparticles.2) This is because platinum–nitrogen interaction finely tunes the electronic structure of catalyst surface.

Herein, we studied Pt–Ni nanoframe3) supported on NC (Pt–Ni NF/NC) or non-doped carbon black (Pt–Ni NF/C) for the ORR.4) In order to clarify support effects on the Pt–Ni NF, we performed in situ Pt L3-edege X-ray absorption fine structure (XAFS) measurements of Pt–Ni NF/NC and Pt–Ni NF/C. The ORR activity of Pt­–Ni NF/NC was higher than that of Pt­–Ni NF/C. In situ Pt L3-edge XAFS spectroscopy of Pt­–Ni NF/NC showed almost no potential dependence of the intensity of the white line region, whereas Pt­–Ni NF/C showed some changes. This result suggests that the formation of Pt surface oxide was suppressed for Pt­–Ni NF/NC under electrochemical conditions, leading to the improvement of the ORR activity.

Acknowledgments　

This work was supported by NEDO.

References

1) V. Stamenkovic et al., Angew. Chem., 118, 2963-2967 (2006)

2) Y. Zhou et al., Energy Environ
Sci., 3, 1437 (2010)

3) C. Chen et al., Science,
343, 1339-1343 (2014).

4) M. Kato et al., ACS Omega, 3, 9052‒9059 (2018).
Carbon Nanostructure Supported Ion Exchange Platform for Efficient Electrochemical Removal of Cesium from Aqueous System
Authors: Devnani Harsha , Ingole Pravin Popinand , Sandal Nidhi
Published: February 2020

Recently, electrochemical adsorption through pre-concentration of heavy metals on the modified electrodes has been employed as a potential method for removal of heavy metals from aqueous solutions. With this perspective, a novel electrochemical separation system has been developed based on functionalized carbon nanostructures for removal of heavy metals including radionuclide from wastewater. Various carbon nanostructures were compared for their electrochemical adsorption capacity with respect to heavy metal pollutants encountered in waste water. While multi-walled carbon nanotubes and reduced graphene oxide have been explored immensely for sensing, graphitic carbon nitride is still new in the scenario. It was found to show impressive potential for heavy metal decontamination in the present study. Further, it was functionalized with an ion exchange molecule to explore the synergistic effect. This novel structure is proposed to enhance the conductivity of ion exchange molecule for efficient and speedy heavy metal decontamination with aprreciable reusability. Besides being considerably stable, it also allows electrochemical regeneration of the hybrid for subsequent use. The electrochemical adsorption/desorption system using carbon nanostructure supported ion exchange hybrid is a promising strategy for heavy metal decontamination from waste water.

Figure 1
Nanoindentation of Polyethylene/Polypropylene Tri-Layer Separator Under Dry and Wet Conditions
Authors: Meyer Andrew William
Published: February 2020

Polymer separators play an important role in lithium ion batteries by preventing contact between the positive and negative electrodes while allowing the ions to pass through. It is, therefore, important to study not only the chemical properties, but also mechanical properties of separators. Although mechanical properties of separators have been measured using, for example, tensile tests or dynamic mechanical analysis (DMA), local mechanical properties, especially when the separators are immersed in the electrolyte, are not well known. The local deformation behavior under compression is important since the separator is usually in contact with the porous electrode layer which has micro- and nano-meter length scale surface roughness. To study the mechanical properties in a more realistic environment, a polyethylene/polypropylene tri-layer separator (Celgard 2325) was investigated, under both dry and wet conditions, using a nanoindentation system. The indentation measurements were preformed inside of an argon filled glovebox which allowed for indentation in an organic electrolyte. A piece of separator was first saturated with several drops of electrolyte before several more drops were added to create a thin electrolyte layer in which the indenter tip remained submerged during indentation to avoid the surface tension effect on the measured load vs. displacement curves. By analyzing these curves, the elastic modulus and hardness were obtained. A t-test for two population means was conducted to ascertain whether there is a statistical significance between the dry and wet conditions. Under wet conditions, the separator displayed a larger elastic modulus of 0.884 GPa and hardness of 0.0478 GPa compared to 0.801 GPa and 0.0418 GPa under dry conditions, respectively. The incompressibility of the liquid electrolyte may be responsible for the measured differences. This study provides a more representative set of mechanical properties that should be considered especially for use in computational modeling and design of battery cells.
The Role of Surface Chemistry in Impedimetric Aptasensing
Authors: Ang Wei LI
Published: February 2020

Surface chemistry is a key parameter in the choice of proper materials for electrochemical detection. It has been previously shown that the presence of oxygen containing groups (OCGs) on the surface of graphene oxide (GO) can be both effective and detrimental. This poses a question when GO materials are used as electrochemical platforms for biosensing. In this work, we study how the surface chemistry of graphene oxide nanocolloids (GONCs) affects the impedimetric biosensing of ochratoxin A (OTA), in terms of immobilization of biorecognition element and detection step. OCGs on GONCs were tuned by applying increasing reduction potentials from 0.3 V to 1.2 V, resulting in GONC platforms with decreasing amounts of oxygen functionalities. It was discovered that the sensitivity of biosensing is correlated to the residual amount of OCGs on GO surface. For a more detailed investigation, three representative materials, namely unreduced GONCs, as well as GONCs reduced at potentials of 0.8 V and 1.2 V were chosen. Results were compared in terms of calibration sensitivity, selectivity and reproducibility of the impedimetric response. GONCs reduced at 1.2 V have shown the best electroanalytical response for the impedimetric detection of OTA. These findings are anticipated to contribute to the design of novel biosensors, whereby an optimized platform is employed for the immobilization of the biorecognition element.
Structural Effect of 10um Depth Surface Relief on the Cycling Behavior of Lithium Metal Anode
Authors: Ahn Jinhyeok , Jang Eun Kwang , Park Eun Ji , Yoo Min Jeong , Cho Kuk Young
Published: February 2020

Lithium metal anodes (LMAs) are required to fulfill higher energy density battery system beyond lithium ion batteries (LIBs). However, practical application of LMAs has been hindered from poor cycle life and safety issue caused by lithium (Li) dendrite growth and inhomogeneous Li plating/stripping. Recently, the Li surface patterning technique was developed for the lower surface current density and stable Li plating/stripping for LMB. Nevertheless, the impact of various factors such as the pattern morphology and charge-discharge condition on Li anode was much unexplored. Here, we report the comparison of the cycling behavior of 10 μm depth continuous and discontinuous surface relief on lithium anode under the Li overflow conditon with varying induced current density. Both continuous and discontinuous surface relief efficiently reduced dendritic Li growth and improved Li plating/stripping behavior than the bare Li anode. The most controlled Li plating/stripping was observed along the discontinuous surface relief. This result affects the improved cycle performance and lowered overpotential of surface patterned lithium metal anode. Furthermore, it was revealed that the 10 μm depth surface relief can not only be applied on the thin (20 μm) Li anode but also enhance cycling stability.
Growth of Metal Nanoparticles on Electrostatically-Charged Polymers
Authors: Zhang Jinyang
Published: February 2020

Growth of Metal Nanoparticles on Electrostatically-Charged Polymers

Jinyang Zhang and Simone Ciampi*

School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University, Bentley, Western Australia 6102, Australia

Static electrification of insulators is a familiar topic: hair attracted by a party balloon or ink or laser printers transferred to a toner1. Contact electrification develops on the surface of insulators which are brought in and out of. Statically charged surfaces has been known to mediate redox work, but the scope in electrochemistry of charged dielectrics remains poorly understood. In 2008, Liu and Bard demonstrated that metal ions can be reduced to elemental metal on a charged polytetrafluoroethylene surface and they proposed that charge carries are electrons2. However, in 2011, Bartosz A. Grzybowski demonstrated a random “mosaic” of each polymer surface after contact and separated, suggesting that polymer fragments are responsible of the electrification process3. Here we report that the magnitude of electrochemical work on electrostatically-charged polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC) samples is material-dependent. We show that the magnitude of redox work mediated by a charge insulator is governed by a trade-off between its ionization energy (IE) and electron affinity (EA)4. Using XPS, AFM and TEM we have quantified metal deposition on electrostatically-charged PDMS, PTFE and PVC samples. Quantum chemical methods are used to show that anions are the effector of the redox work and polymer, with plastics of the largest negative value of EA (making negative charges unstable) but that at the same time it will ionize into cationic fragments with relative ease, leads to surfaces able to mediate redox work to the largest extent. This work extends our understanding of the molecular nature of static electricity and may find applications in single-electrode electrochemistry and in the study of electrostatic catalysis on chemical reactivity.

References

Childress, C. O.; Kabell, L. J., Electrostatic Printing System. US Patent No. 3,081,698, 163: 1963.

Liu, C.-Y.; Bard, A. J., Electrostatic Electrochemistry at Insulators. Nat. Mater.
2008,
7 (6), 505–509.

Baytekin, H.; Patashinski, A.; Branicki, M.; Baytekin, B.; Soh, S.; Grzybowski, B. A., The Mosaic of Surface Charge in Contact Electrification. Science
2011,
333 (6040), 308–312.

Zhang, J.; Rogers, F.; Darwish, N.; Gonçales, V. R.; Vogel, Y. B.; Wang, F.; Gooding, J. J.; Peiris, M. C.; Jia, G.; Veder, J.-P., Electrochemistry on tribocharged polymers is governed by the stability of surface charges rather than charging magnitude. Journal of the American Chemical Society
2019.

Figure 1
Energy Storage Technology in AIST; The Background of the Diversity
Authors: Sakaebe Hikari
Published: February 2020

Efficient energy network system is required and in Department of Energy and Environment (EE), National Institute of Advanced Industrial Science and Technology (AIST) is responsible for realizing it by R&D of energy technologies. Our mission is implementation of Japanese policy for technology. For this purpose, 5 Research Institutes and 3 Centers concerning energy conservation, environmental management, science for safety and sustainability, energy storage, renewable energy are organized in EE.

One of the most important subjects of AIST, and EE is battery technology. Our Research Institute of Electrochemical Energy (RIECEN) is responsible for this issue and plays a central role in AIST and Japan. For example, Research and Development Initiative for Scientific Innovation of New Generation Batteries 2 (RISING2) is Japanese largest national project for R&D of the batteries, and RIECEN, AIST forms research base with Kyoto University for open innovation of the new battery systems. In this project and previous RISING, author has been engaged as one of the group leaders for 5 years. Educational background might be the basis for the reason for me to be in this position.

EE department includes c.a. 8% female researchers and 4% foreign researchers. RIECEN in EE keeps 12% female researchers and this is more than the average of AIST total (10%). In the battery technology, we need a wide variety of the academic field of the study. This could act in good direction for diversity. We hope this properties could be the source for flexible activities in constructing the energy systems by best-mix.
(Invited) Finding Creativity and Balance in a Technical Career
Authors: Hanson Karrie J.
Published: February 2020

When I was in graduate school in 1979 studying electorochemical engineering at Berkeley, Joan Berkowitz was the ECS President. It never crossed my mind that this was unusual - it seemed about right that a woman was in charge once in awhile. From that starting inspiration 40 years ago, I have enjoyed a long and interesting career (from electrochemistry to software product development), and also raised three daughters (who are themselves scientists and journalists, and still the sparkling joy of my life). In this talk, I will describe some of my professional experiences, my evolution as an inventor, some early volunteer work for the the ECS, some interesting sidetracks. I’ll reflect on how to define a career so it can be balanced with competing passions.
(Invited) Four Decades of Diversification and Progress at ECS
Authors: Calvo Roque
Published: February 2020

Since its founding on April 1902, The Electrochemical Society has supported a diverse community of scientists and engineers who have participated in the meetings, published in the journals and who have been recognized for their achievements through the ECS awards program. ECS is a global community with members, authors and meeting attendees residing in 80 countries. The ECS community is a broad association of researchers with experience ranging from students to world-recognized scientists whose affiliations represent a healthy mix of government, academia and industry research institutions. The ECS community is multidisciplinary with participants from an extensive scope of technical interests connected to the field of electrochemical and solid-state science and technology. Finally, after four decades of progress, the ECS Community is diverse with significant female achievement through participation in the programs and leadership of the organization.

Female diversity in ECS essentially began with the election of the first female Vice President Joan Berkowitz in 1976. After her service as Vice President, she was elected as the first female President and Board Chair leading ECS in that role from 1979-80. Former ECS Executive Director Roque Calvo, began working at ECS when Dr. Berkowitz was finishing her service on the Board. During his 38-year career he had the opportunity to work with the six distinguished female ECS Presidents including: Kathryn Bullock (1995-96), Jan Talbot (2001-02), Robin Susko (2004-05), Esther Takeuchi (2011-12), and Johna Leddy (2017-18). Additionally, he worked with five female leaders who were elected to the Office of ECS Secretary or Treasurer; all of which provided him with the opportunity to collaborate with these dynamic women leaders as they influenced change and progress in ECS.

Based on his experience as an ECS staff member during this era of change, Roque Calvo will reflect on the unique contributions of these female leaders and those of several others like Geraldine Schwartz from the 1st Class of ECS Fellows, who worked behind the scenes to advance the Society’s mission. Their collective influence has led to significant growth and development of ECS programs and further stimulated diversity and inclusion in the organization. From the beginning, it was evident that the ECS community placed great importance on inclusiveness and diversity. These values are reflected in the ECS objectives, activities, governance, staff and culture of the organization and are critical components of the Society’s success and accomplishments. Since Joan Berkowitz’s pioneering role as the first female President, women leaders have had a major impact on the Society’s success in achieving its’ primary mission…to advance electrochemical and solid-state science and technology.
(Invited) Electrochemical Processes for in Situ Resource Utilization
Authors: Hintze Paul
Published: February 2020

In situ resource utilization (ISRU) is the practice of generating resources when humans are away from Earth. The goals of ISRU include the generation of rocket propellants, building materials, and life sustaining commodities from such resources as the Mars atmosphere, lunar regolith, and even trash.

There are many technology options that are currently at different technology readiness levels. This talk will review some of the more mature ISRU technologies and show were electrochemical processes have the potential to be a better option. The generation of oxygen from lunar regolith has been demonstrated using hydrogen and carbothermal reduction processes. Electrolysis of regolith when it is molten or dissolved has the potential for increased yields.

Propellant production on Mars can be achieved through capture of carbon dioxide from the Mars atmosphere and water from the Mars soil. The water is split to oxygen and hydrogen, which is used to reduce carbon dioxide to methane, resulting in production of methane and oxygen. The co-electrolysis of carbon dioxide and water can produce methane and oxygen in a single process vessel, reducing the complexity of the overall system. Recent work has shown that this can be done when carbon dioxide is dissolved in an ionic liquid. The same ionic liquid shows a high capacity for carbon dioxide uptake and can be used to collect carbon dioxide.

Because ISRU systems are extremely mass constrained, there is a need for gas and water cleanup methods that do not use consumables. Some of the ISRU cleanup challenges and potential solutions, such as electro-dialysis to clean water, will be discussed.
3D Printed Hierarchical Porous Carbon Aerogels for Supercapacitors at Ultralow Temperatures
Authors: Yao Bin , Li Yat
Published: February 2020

Supercapacitors (SCs) represents an emerging class of fast-charging and stable energy storage devices and have been extensively studied in recent years. However, most of the previous research are focused on SCs in aqueous and room temperature conditions. Improve the performance of SCs, especially in low-temperature environments, is significantly important for prolonged space exploration. This talk will report our new findings of using 3D printing method to fabricate carbon aerogels for supercapacitors at ultralow temperatures. The 3D printed carbon aerogel electrodes with periodic large pores have shown much improved electrochemical performance than the non-3D printed counterparts at low temperatures. More importantly, hierarchical pore structure with large periodic pores, macropores, mesopores and micropores in the 3D printed carbon aerogels enable the porous electrodes to achieve an excellent capacitance of over 150 F/g even under -70 °C. Kinetic analysis further reveals the favorable ion diffusion property in the 3D printed hierarchical porous electrodes. Moreover, the effects of each type of pore structure on capacitance at low-temperature will also be talked. This talk will for the first time demonstrate the superiority of 3D printed porous electrodes for ultralow temperature energy storage, which might open a new door for the future work on high-performance fast-charging energy storage system for space missions.