bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Alkyl Chain on a Neutral-Carrier for Use in Selective Membranes Mercury Ions
Authors: Juarez-Gomez Jorge , Ramirez-Silva Maria Teresa , Perez-Garcia Francisco , Palomar-Pardavé Manuel , Romero-Romo Mario , Rojas-Hernández Alberto
Published: February 2020

The recognition element or ionophore of the ISEs, is the main constituent to be considered during their building, which is the reason to synthesize four molecules of the same family, all of them candidates to be the best recognition element for building a novel Hg(II) ions selective electrode with a solid inner contact. The difference between the four structures is the alkyl group bound to one of the sulphur donating groups, the aliphatic chain can be: methyl, ethyl, propyl or butyl. The electrodes were prepared for each of the ionophores synthesized using the composition of the ionophore membrane: o-NPOE:PVC:NaTPB with 5:62:33:1.0mg (%, w/w). The best neutral-carrier for the selective determination of mercury ions proved to be the ionophore containing the methyl in its structure, as demonstrated by its detection limit (9.1 ± 0.8) x 10−10 mol L-
1, linear range (1.0 x 10−9 to 1.0 x 10−1) mol L-
1 and a Nernstian response (29.8 ± 0.4) mV decade-1.
Determination of the Antioxidant Capacity of "Pistache Amargo" Using a Biosensor Based on Laccase Trametes Versicolor
Authors: Juarez-Gomez Jorge , Ramirez-Silva Maria Teresa , Palomar-Pardavé Manuel , Romero-Romo Mario , Salinas-Hernández Pastora , Morales-Anzures Fernando
Published: February 2020

In the Isthmus of Tehuantepec region of Oaxaca, Mexico, it grows a variety of Pistache of the Anacardiaceae family; the fruit comprises about 68 % weight oil and is rich in polyphenolic compounds, which are antioxidant molecules of great interest today for their beneficial implications to human health, as presently there is a strong interest in finding natural sources of antioxidants. Therefore, this work presents the spectrophotometric studies using the DPPH radical method for the determination of the antioxidant capacity equivalent to caffeic acid in different extracts of the residual pulp "Pistache Amargo". The spectrophotometric method is contrasted with an electrochemical method using a biosensor based on the enzyme Laccase Trametes Versicolor immobilized on a polymeric membrane of polyvinyl alcohol.
Simultaneous Recording of Chronoamperometric L-Glutamate Current and Field Excitatory Postsynaptic Potentials in Mouse Hippocampal Slice
Authors: Matsumura Ryosuke , Hirano-Iwata Ayumi , Niwano Michio , Bliss Tim V. P. , Sugawara Masao
Published: February 2020

L-Glutamate is a major excitatory neurotransmitter in the central neuronal systems and plays a vital role in brain development, synaptic plasticity and neuropathology. Simultaneous recording of presynaptically released L-glutamate and postsynaptic events (field excitatory postsynaptic potentials (EPSPs)) is particularly important for investigating the direct relation between presynaptic L-glutamate dynamics and postsynaptic activities. Here we report on combination of field EPSP recordings and time-resolved measurements of stimulus-evoked L-glutamate using the capillary-type enzyme microsensors in mouse hippocampal slices. The capillary-type L-glutamate microsensor was based on glutamate oxidase (GluOx), which was prepared according to ref. (1). It was found that application of electric stimuli to mouse hippocampal slices resulted in generation of a large L-glutamate-insensitive capacitive current both at an L-glutamate microsensor and blank microsensor that lacks GluOx, probably due to an unintentionally formed junction between the circuits of the amperometric and field EPSP measurements. The origin of the capacitive current was investigated using electrical impedance spectroscopy and circuit simulation. Our approach to extract a faradaic signal from the observed current was to sample a current amplitude when the capacitive transient current dropped virtually to zero. After this analysis, a clear response was observed following 2 Hz electric stimulation at the L-glutamate microsensor, while no significant response was observed at the blank microsensor. The reliability of the extracted signal was examined by investigating several treatments that manipulate release probability of L-glutamate.

References

(1). S. Hozumi, K. Ikezawa, A. Shoji, A. Hirano-Iwata, T. Bliss and M. Sugawara, Biosens. Bioelectron. 26, 2975–2980 (2011).
Nano and Bio Sensors for Life Sciences Applications
Authors: Aguilar Zoraida Pascual , Al-Ogaidi Israa , Suri Savan , Gou Honglei , Wu Nianqiang , Xu Hengyi , Wei Hua , Wang Andrew
Published: February 2020

Sensors applications represent one of the most promising commercial products developments. The Global Industry Analysts predicted that in 2017[1], the global market for biosensors in medical diagnostics would reach US$16.5 billion. The increased R&D focused on highly accurate real-time diagnosis using biosensors and the demand for biosensors based equipment drives this market. The emergence of new technologies including nanomaterials based-sensors, microfluidics, and non-invasive sensors also act as other market drivers. Until 2016, diagnostic sensors for point of care will continue to drive the market while biodefense and environmental markets are predicted to have the highest CAGRs at 13%–15%.[2] This paper will focus on the preliminary studies in the development of nano and bio sensors for life sciences applications. Data gathered for detection of disease biomarkers using nanotechnology, electrochemistry, and colorimetric methods will be discussed. Studies on the development of lateral flow strip tests, glass slide-based sensors, and 96-well plate assays using quantum dots fluorescence, absorbance, and electrochemical detection methods will be presented.[3],[4][5]

1 Global Industry Analysts, Inc., accessed on February 3, 2014. http://www.prweb.com/releases/medical_biosensors/environmental_biosensors/prweb9242715.htm

2 Dr. Rajender Thusu, Frost and Sullivan Sensors: Strong Growth Predicted for Biosensors Market, http://www.sensorsmag.com/specialty-markets/medical/strong-growth-predicted-biosensors-market-7640

3 Israa Al-Ogaidi, Zoraida P. Aguilar, Savan Suri, Honglei Gou, and Nianqiang Wu, Dual Detection of Cancer Biomarker CA125 Using Absorbance and Electrochemical Methods, Analyst, 2013, DOI: 10.1039/c3an00668a

4H. Xu, Z.P. Aguilar, H. Wei, A. Wang, “Development of semiconductor nanomaterial whole cell imaging sensor on glass slides,” Special Issue: Nano and Bio Sensors, Frontiers in Bioscience, 2011, E3: 1013-1024.

5 X. Huang, Z. P Aguilar, H. Li, W. Lai, H. Wei, H, Xu, Y. Xiong, Fluorescent Ru(phen)3
2+ doped silica nanoparticles-based ICTS sensor for quantitative detection of enrofloxacin residues in chicken meat, Anal Chem, 2013, 85, 5120-5128.
Autonomous Magnetoelastic Biosentinels for the Detection and Capture of Invasive Pathogens
Authors: Horikawa Shin , Chai Yating , Wikle Howard Clyde , Chin Bryan A.
Published: February 2020

This paper investigates the use of self-propelled magnetoelastic (ME) biosentinels to seek out and capture pathogenic bacteria in a stagnant liquid. These ME biosentinels are composed of an asymmetric-shaped ME resonator coated with a filamentous landscape phage that specifically binds with the pathogen of interest. When a time-varying magnetic pulse is applied, the ME biosentinels can be placed into mechanical resonance by magnetostriction. The resultant asymmetric vibration then generates a net force on the surroundings and hence generates autonomous motion in the liquid. As soon as the biosentinels find and bind with the target pathogen through the phage-based biomolecular recognition, a change in the biosentinel’s resonant frequency occurs, and thereby the presence of the target pathogen can be detected. In order to actuate the ME biosentinels into mechanical resonance of a desired mode, modal analysis using the three-dimensional finite element method was first performed, followed by determination of the resonant frequency. In addition, the net force due to the asymmetric vibration was calculated, and the resultant motion of the biosentinels was simulated. Both dynamic simulation and experimental results showed that the ME biosentinels can move autonomously through the liquid and actively bind with the target pathogen.
Carbon-MEMS (CMEMS) and Carbon-NEMS (CNEMS): Multi-Length Scale Manufacturing in Carbon
Authors: Madou Marc J
Published: February 2020

Carbon micro- and nanofabrication techniques (C-MEMS and C-NEMS) are based on the pyrolysis of patterned polymers at different temperatures and in different ambient atmospheres [1,2]. The resulting carbon material is typically found to be glassy carbon-like in composition and in electrical and electrochemical behavior [3,4]. Carbon, because it is brittle and hard, is a difficult material to machine, polymers on the other hand can be machined easily in a wide variety of machine tools and as a consequence shapes and sizes that are difficult to achieve directly in carbon can easily be made by patterning a polymer first and then converting it to carbon.

In this contribution we emphasize embodiments of C-MEMS and C-NEMS that allows us to fabricate the very smallest carbon features (nanometer and micrometer range): a photoresist is either patterned by lithography and is subsequently pyrolyzed at high-temperature in an oxygen-free environment or photoresist nanofibers are deposited by electrospinning and then pyrolized [5]. The C-MEMS and C-NEMS applications we are highlighting in this paper are ultrasensitive carbon interdigitated electrode arrays (IDEAs) for nanoelectrochemistry [6] and suspended carbon nano-wires for sensor application in the liquid and gas phase [7].

REFERENCES

[1] C. Wang, G Jia, L.H. Taherabadi. M.J. Madou, J. Microelectromech S 14 (2005) 348-358.

[2] C. Wang, M. Madou, Biosens. Bioelectron. 20 (2005) 2181-2187.

[3] N.E. Hebert, B. Snyder, R.L. McCreery, W.G. Kuhr, S.A. Brazill, Anal. Chem. 75 (2003) 4265-4271.

[4] S. Ranganathan, R.L. McCreery, S.M. Majji, M. Madou, J. Electrochem. Soc. 147 (2000) 277-282.

[5] C.S.Sharma, A.Sharma and M.Madou, Langmuir 26(4), 2218–2222 (2010)

[6] J. I. Heo, D. S. Shim, G. Turon Teixidor, S. Oh, H. Shin, M. J. Madoub, Carbon Interdigitated Array Nanoelectrodes for Electrochemical Applications, Submitted to the Journal of Electrochemical Society

[7] C.S.Sharma, A.Sharma and M.Madou, submitted to Carbon
Advances in Dielectrophoresis As a Biotechnology Tool
Authors: Pethig Ronald
Published: February 2020

Dielectrophoresis (DEP) has been widely studied for its potential as a biomarker-free method of sorting cells based on their intrinsic dielectric properties. Under appropriate experimental conditions the DEP frequency spectrum typically exhibited by a viable mammalian cell in suspension is characterised by two frequencies, f
xo1 and f
xo2. At these two characteristic frequencies the effective conductance and capacitance values of the cell exactly match those of the fluid it has displaced, and are commonly known as the DEP cross-over frequencies. At low frequencies (< 10 kHz) viable cells typically exhibit negative DEP and move away from electrodes, with the transition to positive DEP occurring at f
xo1 - where the cells move towards high field regions at the electrodes. A transition back to negative DEP occurs at f
xo2 (~150 MHz). The dielectric properties of the cell membrane and cell interior can be evaluated from knowledge of the dielectric properties of the suspending fluid, and changes of the physico-chemical properties of the suspending fluid can be used to control the frequencies f
xo1 and f
xo2.

Theoretical and experimental evaluations of f
xo1 have been extensive and exploited in practical applications of DEP [1-5]. The current status of this, both in research and commercial exploitation, will be reviewed in this presentation. The factors that control the high frequency DEP cross-over at f
xo2 are now under investigation. The status of the ‘exploration of this 2nd frontier of DEP research’ will be described.

1. Pethig, R. Review Article - Dielectrophoresis: Status of the theory, technology, and applications. Biomicrofluidics
4, 022811 (2010).

2. Pethig, R.; Menachery, A.; Pells, S.; de Sousa, P. Dielectrophoresis: A review of applications for stem cell research. J. Biomed. Biotechnol., e182581 (2010).

3. Gagnon, Z.R. Cellular dielectrophoresis: Applications to the characterization, manipulation, separation and patterning of cells. Electrophoresis
32: 2466-2487 (2011).

4. Pethig, R. Dielectrophoresis: An assessment of its potential to aid the research and practice of drug discovery and delivery. Adv. Drug Deliv. Rev.
65: 1589-1599 (2013).

5. Gascoyne, P.R.C. and Shim, S. Isolation of circulating tumor cells by dielectro-phoresis, Cancers
6: 545-579 (2014).
Fabrication, Characterization, and Modeling of Field-Effect-Transistor Nanoribbon Biosensors
Authors: Vogel Eric M
Published: February 2020

For over 30 years, field effect transistors (FETs) have been used as sensors. In the past, Ion-Sensitive-FETs (ISFET) were based on bulk Metal-Oxide-Semiconductor (MOS) FET designs and the device was gated by biasing the electrolyte through the reference electrode. Recently, functionalized silicon nanowires and silicon-on-insulator (SOI) devices have been introduced for their greater sensitivity in detecting proteins, DNA and even single viruses.

This work reviews a variety of issues that impact the properties of SOI FET nanoribbon sensors.1-7 The ability to stabilize and control the attachment of cells on the sensor surface is critical. Therefore, the reliability and reproducibility of self-assembled-monolayers such as aminosilanes will be presented. Biological solutions consist of protein or DNA in an electrolytic solution containing salt ions. Some of these ions, such as Na, have long been known to cause instabilities in MOS devices. The effect of mobile ions on SOI-based sensors will be presented. The SOI-based sensor structure results in the electrolyte voltage being capacitively coupled to the back gate voltage. The impact of this coupling on sensor response will be described. Physically realistic SPICE models were developed and illustrate the response of both pH and biosensors with a multi-gate model. The model demonstrates good agreement to experimental data including the impact of Debye screening and site binding charge. The benefits and use of novel 2D semiconductors for biosensing will also be described.

ACKNOWLEDGMENTS

The author would like to acknowledge the previous and current researchers who contributed to this work including: P. G. Fernandes, K. D. Cantley, G. A. Mahmud, A. Tarasov, M. Y. Tsai, O. Seitz, R. Tian, N. Karnik, H. Stiegler, R. A. Chapman, and Y. J. Chabal. The author would also like to acknowledge the support of NSF CBET Award #1264705, the SRC Texas Analog Center of Excellence, and Texas Instruments.

REFERENCES

P. G. Fernandes, R. A. Chapman, O. Seitz, H. J. Stiegler, H. C. Wen, Y. J. Chabal, and E. M. Vogel, IEEE Electron Device Letters
33, 447-449 (2012).

P. G. Fernandes, H. J. Stiegler, B. Obradovic, R. A. Chapman, H.-C. Wen and E. M. Vogel, Sensors and Actuators B
161, 163-170 (2012).

K. D. Cantley, P. G. Fernandes, M. Y. Zhao, H. J. Stiegler, R. A. Chapman, in Midwest Symposium on Circuits and Systems Conference Proceedings, 370-373 (2012).

O. Seitz, P. G. Fernandes, G. Mahmud, H. –C. Wen, H. J. Stiegler, R. A. Chapman, E. M. Vogel, Y. J. Chabal, Langmiur
27, 7337-7340 (2011).

R. A. Chapman, Fellow, P. G. Fernandes, O. Seitz, H. J. Stiegler, H.-C. Wen, Y. J. Chabal, and E. M. Vogel, IEEE Transactions on Electron Devices
58, 1752-1660 (2011).

O. Seitz, P. G. Fernandes, R. Tian, N. Karnik, H.-C. Wen, H. Stiegler, R. A. Chapman, E. M. Vogel and Y. J. Chabal, Journal of Materials Chemistry
21, 4384-4392 (2011).

P. G. Fernandes, O. Seitz, R. A. Chapman, H. J. Stiegler, H.-C. Wen, Y. J. Chabal, and E. M. Vogel, Applied Physics Letters
97, 034103 (2010).
Microfabricated Si Chips Containing Human Ether-a-Go-Go-Related Gene Channels As a Platform for Drug Safety Screenings
Authors: Hirano-Iwata Ayumi , Ishinari Yutaka , Kimura Yasuo , Niwano Michio
Published: February 2020

Reconstitution of ion channel proteins in artificial bilayer lipid membranes (BLMs) provides an excellent system for drug screenings. However, the mechanical fragility of BLMs prevents them from being widely used. Recently, we have succeeded in the formation of mechanically stable BLMs by preparing membranes in microapertures fabricated in silicon (Si) chips (1). The key feature for BLM stabilization is probably the tapered shape of the aperture edge, which allows reducing the stress on the bilayer at the aperture edge. In this presentation, we report on an application of this stable BLM device to measure ion currents of human ether-a-go-go-related gene (hERG) channels (2), which have been found to be related to serious arrhythmic side effects following drug treatment. Microapertures (diameter: 20-60 micrometer) were fabricated in a silicon nitride (Si3N4) layer on a Si chip. The surface of the Si chip was coated with thermal oxide and Teflon-AF. After the chip was treated with a silane-coupling reagent, artificial BLMs were prepared in the microapertures by folding up two phospholipid monolayers in the apertures. Owing to the use of SiO2/Teflon dielectric layer, the current noise level of the BLM was reduced, and clear single-channel events with conductance of 11 ± 1.2 pS were observed for hERG channels. This conductance value is similar to a reported one (12 pS) by the patch-clamp method. The channel current was completely blocked by E-4031, a specific blocker for hERG, and astemizole, an antihistamine that has been withdrawn due to its side effect on hERG channels. Thus the sensitivity of the hERG channels to typical drugs was retained in the Si chips. The BLM with incorporated hERG channels was stable for 65 h and tolerant to repetitive solution exchanges. The next step is to extend this stable BLM device to a multisite array format. The realization of an ion channel array will open a variety of applications, including high-throughput drug screening procedures that can be a complement to the patch-clamp method.

References

A. Hirano-Iwata, K. Aoto, A. Oshima, T. Taira, R. Yamaguchi, Y. Kimura, M. Niwano, Langmuir, 26, 1949–1952 (2010).

A. Oshima, A. Hirano-Iwata, H. Mozumi, Y. Ishinari, Y. Kimura, and M. Niwano, Anal. Chem., 85, 4363-4369 (2013).
Shape Anisotropy in Magneto-Impedance NiFe-Based Microsensors
Authors: Cortés Meritxell , Peng Tao , Woytasik Marion , Moulin Johan
Published: February 2020

MI sensors are based on the impedance variations due to changes of the skin depth when applying an external magnetic field. They present high sensitivity but relative spatial resolution. Thin film technology is an interesting way to reduce size and realize arrays of microsensors.

The present work reports the fabrication and characterization of microsensors based in the MI effect. The sensors consisted in a multilayered structure of two ferromagnetic layers with a copper layer in between. Permalloy has been chosen as magnetic material due to both its magnetic properties and the possibility of obtaining thick layers of this material by means of electrodeposition. Silicon substrates and UV thick photolithography have been used to perform the micromolding of the sensors. Electrodeposition conditions have been optimized in previous works [1]. A post annealing process under magnetic field has been applied in order to study its influence on the sensibility of the sensors. The size of the obtained sensors was from 1 mm x 100 µm to 5 mm x 250 µm. The thickness of the copper and NiFe layers was ranging from 2 to 10 µm.

The optimal excitation frequency leads to a matching between the film thickness and the skin depth, what has been experimentally validated: from 0.8 MHz for 5 µm thick NiFe films to 3 MHz for 2.5 µm thick NiFe films. The sensors have been characterized at these frequencies as a function of the magnetic field and the best results have been obtained for sensors annealed at 300°C under transverse magnetic field. Both the magneto-impedance maximum and the anisotropy field depend on the aspect ratio of the structure what highlights the influence of the shape anisotropy. The narrower structures give the highest maximum of the magneto-impedance (170% of variation of impedance) and to the higher anisotropy field (4200 A/m).
Aqueous Lithium-Iodine Battery
Authors: Byon Hye Ryung , Zhao Yu
Published: February 2020

Higher energy density and cycling efficiency are required for the next generation of batteries. Iodine is an attractive material towards the high energy density battery thanks to its high theoretical energy density of ~0.74 kWh kg–1 and 3.7 kWh L–1. However, due to the nature of low ionic conductivity of solid lithium iodide, the primary lithium-iodine (Li–I2) batteries can only support for extremely low current rate applications such as a pacemaker. To improve rechargeability and rate capability, we have proposed aqueous cathode with a triiodide/iodide (I3
–/I–) redox couple to construct a low-cost, non-flammable, and environmentally friendly Li–I2 battery.[1-4] The aqueous cathode can contain high concentration of I3
–/I– redox couple using I2 and I– ion, which are transformed to I3
– in an aqueous medium (I2(s) + I– ↔ I3
–, K (equilibrium constant) = 723). The electrochemical reaction of this I3
–/I– redox couple in the aqueous cathode leads the total cell reaction of Li–I2 battery: 2Li + I3
– ↔ 2Li+ + 3I–. This aqueous Li–I2 battery demonstrates high storage capacity (~98% of the theoretical capacity), Coulombic efficiency (>99.5%) and cycling performance (>99.5% capacity retention for 100 cycles), which are thus far one of the highest performance among current Li–I2 batteries, aqueous cathode batteries, and lithium-ion batteries using aqueous electrolyte. In addition, high solubility of the I3
–/I– redox couple and appropriate operating potential (~3.5 V vs. Li+/Li and ~0.5 V vs. SHE) but avoiding the electrolysis of water offer a high energy density of ~0.33 kWh kg–1. This energy density can be further improved when equipped with a flow device and aqueous electrolyte reservoir, which allows the aqueous Li–I2 battery to be grid-scale flow battery applications.

References

[1] Zhao, Y; Wang, L.; Byon, H. R. Nature Communications
2013, 4,1896.

[2] Zhao, Y; Byon, H. R. Adv. Energy Mater.
2013, 3, 1630-1635.

[3] Zhao, Y.; Hong, M.; Mercier, N. B.; Yu, G.; Choi, H. C.; Byon, H. R. Nano Lett.
2014, 14, 1085-1092.

[4] Zhao, Y.; Mercier, N. B.; Byon, H. R. ChemPlusChem
2014, in press.
Free-Standing Type Mixed Oxide Oxygen Electrode for Rechargeable Li–O2 Batteries
Authors: Kalubarme Ramchandra S. , Park Ga-Eun , Park Chan-Jin
Published: February 2020

The essential prerequisite for the successful operation of a rechargeable Li–O2 battery is the formation of Li2O2 as reaction products during discharging and the decomposion of Li2O2 to Li and O2 during charging. However, one of the critical problems which limit the practical use of the non-aqueous Li-O2 batteries employing carbon based oxygen electrode is the huge polarization during the discharge/charge process. The high cell polarization may be due to the high activation energy required to produce Li2O2 during discharge and to decompose the Li2O2 during charge. It have been reported that the discharge/charge efficiencies can be improved by the addition of catalytic materials to the carbon supported oxygen electrodes. The cathode catalysts can affect the discharge/charge potentials and determine the rechargeability of the cells. Therefore, it is vital to develop an effectively catalyzed oxygen electrode for the oxygen reduction and oxygen evolution reactions in Li–O2 batteries.

In this study, for the first time we introduce a free-standing type oxygen electrode design, where additional carbon and binders are no longer necessary in the oxygen electrode of Li–O2 battery. A simple and cost effective solvo-thermal techniques was used to fabricate free standing carbon-free electrodes. The highly porous structure of the electrode allows electrolyte and oxygen to diffuse effectively into the catalytic active sites and hence improve the performance. The discharge products would precipitate and decompose on the pores of the free-standing catalyst nanorods. In this study, Mn-based composite oxide was selected as the catalyst candidate and directly deposited on the metallic nickel foam which was applied as the current collector. The electrochemical examination demonstrates that the free-standing electrode without carbon support gives almost the highest cell potential during discharge (2.85 V), the lowest cell potential during charge (3.54 V), almost the highest specific capacity (when considering all active mass in the cathode) and the minimum capacity fading among the rechargeable Li–O2 batteries reported to date. The Li-O2 battery demonstrated cyclability for more than 100 cycles while maintaining a moderate specific capacity of 1000 mAh g-1. Further, the synergistic effect of the fast kinetics of electron transport provided by the free standing structure and the high electro-catalytic activity of the composite oxide enabled the excellent performance of the oxygen electrode for Li-O2 batteries.
Dual-Ion Batteries – Chances for Stationary Energy Storages By Electrode Structuring
Authors: Froböse Linus , Bockholt Henrike , Haselrieder Wolfgang , Kwade Arno
Published: February 2020

In recent years, energy usage has changed and renewable energy sources are getting more and more important. These green sources (e.g. wind or solar energy) are generated locally but are strongly dependent on current weather conditions. Thus the demand on decentralized large-scale energy storages grows continuously.

In order to fit this market dual-ion batteries offer a high promising technology for stationary energy storage. This system has several benefits compared to the classical lithium-ion battery technology: low cost metal-free active materials, safe and non-toxic electrolytes and an extremely high cycling stability or life time, respectively. Furthermore the opportunity to use water soluble binders and thus cheaper aqueous suspensions in electrode production with a distinct reduction of energy during drying should be noticed.

This work focuses on process engineering aspects and challenges of the electrode production in order to transfer this new battery technology towards technical scale and continuous production processes.

Since particularly ion transport limitations due to large intercalating anions during charge are challenging, specific attention is paid to dual-ion battery electrode structures. Process engineering approaches to compensate these hindrances by optimizing the processing route and the electrode structure will be presented. These improvements result in up to 10 % higher capacities compared to available studies and capacity retentions from over 80 % after 5000 cycles (see figure 1).

The electrode structure is the key factor to support the ion transport for a reliable electrochemical performance. The total diffusion coefficient correlates with the ion mass transport within the electrolyte filled pore structure taking the porosity as well as the tortuosity into account. The presented work includes the determination of these structural parameters via mercury intrusion measurements and points out their contribution to understand transport limitation of large anions and its influence on electrochemical performance.
First Principles Study of Lithium and Oxygen Adsorption on the β-MnO2 (110) Surface
Authors: Ngoepe Phuti Esrom , Maenetja Khomotso P , Mellan Thomas , Catlow C Richard A , Woodley Scott M , Grau-Crespo Ricardo
Published: February 2020

The Li-air system is a novel battery technology which promises higher specific energy than Li-ion batteries. In this battery the cathode reaction is not the formation of an intercalation compound but the reduction of oxygen gas in the presence of Li+ ions forming lithium peroxide Li2O2 (or LiOH in the aqueous version).1-5 Manganese oxides may also play an important role in this battery: it has been shown that nanostructured MnO2 in different polymorphic states are able to catalyse the formation and decomposition of Li2O2 in the cathode. Understanding the behaviour of the cathode catalysts is the key for improving the function of Li-air batteries.6

The adsorption and co-adsorption of lithium and oxygen at the surface of rutile-like manganese dioxide (β-MnO2), which are important in the context of Li-air batteries, are investigated using density functional theory. In the absence of lithium, the most stable surface of β-MnO2, the (110), adsorbs oxygen in the form of peroxo groups bridging between two manganese cations. Conversely, in the absence of excess oxygen, lithium atoms adsorb on the (110) surface at two different sites, which are both tri-coordinated to surface oxygen anions, and the adsorption always involves the transfer of one electron from the adatom to one of the five-coordinated manganese cations at the surface, creating (formally) Li+ and Mn3+ species. The co-adsorption of lithium and oxygen leads to the formation of a surface oxide, involving the dissociation of the O2 molecule, where the O adatoms saturate the coordination of surface Mn cations and also bind to the Li adatoms. This process is energetically more favourable than the formation of gas-phase lithium peroxide (Li2O2) monomers, but less favourable than the formation of Li2O2 bulk. These results suggest that the presence of β-MnO2 in the cathode of a non-aqueous Li-O2battery lowers the energy for the initial reduction of oxygen during cell discharge.

1. M. Armand and J. M. Tarascon, Nature, 2008, 451, 652-657.

2. P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J.-M. Tarascon, Nature materials, 2011,

11, 19-29.

3. K. Abraham and Z. Jiang, Journal of The Electrochemical Society, 1996, 143, 1-5.

4. R. Black, B. Adams and L. Nazar, Advanced Energy Materials, 2012, 2, 801-815.

5. J. Christensen, P. Albertus, R. S. Sanchez-Carrera, T. Lohmann, B. Kozinsky, R. Liedtke, J.

Ahmed and A. Kojic, Journal of The Electrochemical Society, 2011, 159, R1-R30.

6. Y. Shao, S. Park, J. Xiao, J.-G. Zhang, Y. Wang and J. Liu, ACS Catalysis, 2012, 2, 844-857.
Invited: Recent Developments in Na-Ion Battery Materials
Authors: Obrovac Mark N
Published: February 2020

Significant advances have been made in Na-ion battery cathode, anode and electrolytes over the past few years. The chemistry of Na-ion battery materials has been shown to be significantly different than for Li-ion materials. These differences are now being exploited as new avenues of research for the development of Na-ion alloy anode materials, oxide anode materials and inexpensive cathode materials have been discovered that don't exist for Li-ion battery materials. As a result of this progress, the energy density, thermal stability or coulombic efficiency of some Na-ion battery materials have been shown to be competitive, or even exceed that of conventional Li-ion battery materials. The recent progress in our lab related to Na-ion battery development will be discussed.
Electronic and Morphological Characterization of Nanostructured Ni-Doped (Ce,Gd)O2-δ Anodes for IT-SOFCs
Authors: Fernandez Zuvich Afra , Soldati Analía , Larrondo Susana , Saleta Martín , Lamas Diego German , Baqué Laura Cecilia , Caneiro Alberto , Serquis Adriana
Published: February 2020

It is well known that CeO2-based materials present excellent catalytic properties for the oxidation of H2 and CH4 fuels [1] and with the incorporation of metal oxides (Gd2O3, Sm2O3, Y2O3) in the CeO2 lattice the oxygen storage capacity, the ionic conductivity and the specific surface area can be significantly improved. Furthermore, the addition of metals such as Ni or Cu enhances the electronic conductivity of the material, thus enabling them as efficient IT-SOFC anodes [2, 3].

A previous study on the microstructure influence in the electrochemical properties of commercial Ce0.9Gd0.1O1.95 (GDC) with several grain sizes, impregnated with NiO [3] to form 40:60 (%wt) composites showed that better performances were achieved with nanocrystalline samples supporting the fact that the optimization of microstructure and morphology are crucial for the development of efficient anodes.

A particular approach to optimize the anode microstructure is to tailor its porosity. In this way, the addition of activated carbon in an intermediate step followed by calcination at 1450ºC resulted in an increase of more than 30% in the anode efficiency [4]. Other composite morphologies can be obtained modifying the way that Ni is incorporated into the material. A common procedure is the impregnation method: the GDC material is submerged in a Ni(NO3)2*6H2O solution, dried in an oven at 90ºC and calcinated at 350ºC to generate NiO [4].

In this work, we present a new modified sol-gel method to incorporate Ni into the precursor solution. This route produces a powder with a very homogeneous Ni distribution. Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS) analysis indicated that this modification resulted in smaller particle sizes with a narrower size-distribution than the observed in commercial Ni-GDC cermets.

The study of the oxidation state and coordination of Ce and Ni in these cermets, simulating in-operando conditions, was performed using synchrotron DXAS technique.

Electrochemical impedance spectroscopy (EIS) analyses allowed to establish a correlation between the electrochemical properties with the sample´s characteristics (microstructure, Ni distribution, etc.).

[1] M.G. Zimicz, S.A. Larrondo, R.J. Prado and D.G. Lamas, Int. Journal of Hydrogen Energy 37 (2012) 14881–14886.

[2] W.C. Chueh, Y. Hao, W. Jung and S.M. Haile, Nature Materials 11 (2012) 155-161.

[3] M. G. Zimicz, P. Núñez, J. C. Ruiz-Morales, D. G. Lamas, S. A. Larrondo, Journal of Power Sources, vol. 238 (2013) 87-94

[4] A. Fernandez Zuvich, A. Caneiro, C. Cotaro and A, Serquis. Procedia Materials Science 1 (2012) 628-635.
Effect of Cation Demixing on the Electrochemical Performance of LSCFO Cathodes for SOFCs
Authors: Baqué Laura Cecilia , Soldati Analía , Troiani Horacio , Serquis Adriana
Published: February 2020

Hydrogen along with renewable energy resources are planned to replace fossil fuels in the near future. Solid Oxide Fuel Cells (SOFCs) are an attractive solution for the transition period between both energy sources since they can operate by using not only hydrogen but also fossil fuels. Nevertheless, the commercialization of these devices is still hindered by their cost and long term degradation. Overall cell degradation depends on the degradation of its main components: anode, electrolyte and cathode.

The use of mixed conducting cathodes such as La1-xSrxCo1-yFeyO3 (LSCFO) improves considerably the performance of the cell. However, one of the most common degradation mechanisms of LSCF reported in the literature is the segregation of Sr.

This work aims at studying the effect of Sr segregation on the electrochemical properties of LSCFO cathodes. LSCFO oxide powders were prepared by solid state reaction and deposited on Ce1-xGdxO2 electrolytes by spin coating. Afterwards, these cells were heat treated at conditions that facilitate the formation of Sr segregates. The electrochemical properties of the cathodes were monitored by electrochemical impedance spectroscopy, while the microstructure was characterized by Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive Spectroscopy, and X-Ray Diffraction. The relation between the Sr segregation phenomena and the changes in the electrochemical performance of the cathode is discussed.
Numerical Study of SOFCs with Transport Properties of Gas and Charged Particles in Composite Electrodes
Authors: Yang Tao , Celik Ismail Bektas
Published: February 2020

In this study, the performance of solid oxide fuel cells is numerically analyzed based upon the transport properties of the gas, ions and electrons within the constructed composite electrodes. The electrodes, consisting of active layer and support layer, are constructed with continuous pathways for gas and charged particles. With the porous-media properties obtained from coordination number theory and percolation theory, the effective ionic and electronic conductivities can thus be calculated. For gas species transportation, more realistic tortuosity (hence diffusion coefficient) is calculated through path line integrations of the velocity field from a numerical simulation of flow passing through porous media. These effective diffusivity and conductivity properties together with the porous-media properties are then utilized in the numerical simulations of button cells to investigate the performance of realistic SOFCs. The current model is first applied to a button cell with artificially constructed electrodes for validation purposes. Finally, the polarization curve and impedance behavior of realistic cells with reconstructed microstructures based on experimental observations are investigated for better understanding of SOFCs.
Invited: Coatings for Robust Metal Bipolar Plates
Authors: Wang Conghua , Tao Yong
Published: February 2020

Metal bipolar plates have advantages of lighter weight and smaller volume over graphite based bipolar plates for automobile fuel cell stacks. Stainless steel has been identified as the primary candidate of the substrate. It has reasonable corrosion resistant, high electrical and thermal conductivity, suitable mechanical properties and formability to form the proper flow field by conventional high speed stamping process. The most important, SS foil is widely commercially available and used in various markets, which result in its low cost comparing with other corrosion resistant alloys.

Additional treatment on stainless steel is necessary for three reasons. First is to reduce the surface electrical contact resistance with gas diffusion layer. The second is to further improve the corrosion resistance of stainless steel in PEM fuel cell stack operation conditions, especially under the transient high voltage conditions. The third is to minimize the absorption of leached ions on the electrode catalyst that may poison electrodes.

Two types of coatings have been investigated. One is the coating using precious metal, the other is precious metal free coating technologies. The advantages and progresses of each coating will be reviewed.

TreadStone has been involved in corrosion resistant metal plate development for several years. A unique design of metal plate coating and its low cost fabrication technology have been developed. It has demonstrated stable long term (2,000 hours) operation for automobile fuel cell stacks under dynamic operation conditions. More development activites are on-going to further reduce the cost with the supports from US Department of Energy.
Interlocking Membrane/Catalyst Layer interface for High Mechanical Robustness of Hydrocarbon Membrane Based PEMFC
Authors: Kim Hee-tak , Park Jung-Ki , Choo Min-Ju , Oh Keun-Hwan
Published: February 2020

For decades, the use of hydrocarbon ionomers in PEMFCs has been constantly attempted as a membrane to replace the commonly used perfluorinated ionomers to lower costs, raise fuel efficiency, and enable easier manufacturing of membrane electrode assembly (MEA). Examples include sulfonated poly(arylene ether sulfone)(s-PAES), sulfonated poly(ether ether ketone) (s-PEEK), and sulfonated polyimide (s-PI). However, when a hydrocarbon membrane is assembled with catalyst layers (CLs) based on a perfluorinated ionomer, a problem of interfacial delamination between the membrane and the CL is often encountered. Due to the poor interface between hydrocarbon ionomer based membrane and perfluorinated ionomer based catalyst layer, in many cases, opportunities to be employed in PEMFC have been denied.To address this problem, hydrocarbon ionomers having chemical structures similar to those of the membrane have been introduced as proton conducting polymer electrolytes into CL. However, due to the low oxygen permeability of the hydrocarbon ionomers, the corresponding CL showed a relatively low power performance. Although such tight interfacial bonding for hydrocarbon membranes has been urgently requested, the problem still remains unsolved.

Here, we propose an interlocking interface structure for providing a tight interfacial bonding between hydrocarbon membrane and perfluorinated ionomer based CL, turning away from the previous focus on chemical modification and physical roughening. This approach is based on a friction force generated due to a difference in volume expansion between the two polymers in an interlocked architecture. The interlocked interface of sulfonated poly(ether ether ketone) and Nafion based CL were realized and evaluated. A profound improvement in interfacial bonding strength was observed with the interlocked architecture. Also, under accelerated stress conditions, interfacial bonding was better maintained with the interlocked interface. The physical interlocking strategy could provide an oppotunity for a lot of hydrocarbon membrane suffering from poor interfacial adhesion to be used in PEMFC.
Vibrational Spectroscopy and 2D Correlation Analysis as a Probe of Structure in Ionomer Membrane Materials
Authors: Korzeniewski Carol , Byun Chang Kyu
Published: February 2020

Infrared and Raman spectroscopy are being applied to gain insights into ionomer membrane properties and the structure and content of water inside membrane pores and channels. In one area of focus, infrared bands associated with interfacial water molecules are being examined. The high internal surface area of materials, such as Nafion 112, enables water interacting with interfaces inside membrane pores and channels to be detected with the use of simple infrared sampling methods. Water structure is probed through measurements on H2O/D2O mixtures in combination with classical vibrational calculations and electronic structure simulations. Additionally, infrared spectroscopy is being investigated as a simple method for determining membrane water content. A combination band associated with vibrations of -CF groups is used as an internal standard. Efforts in applying the approach to compare differences in water uptake by fluorinated ionomer materials prepared with and without inorganic filler materials will be discussed. A second area is focused on Raman spectroscopy as a probe of ionomer framework structure. The potential for in situ Raman measurements in fuel cell systems and depth profiling within membrane via confocal methods is motivating basic studies of membrane structure through Raman measurements on ionomer materials. Early results that indicate the performance of UV Raman will be presented.
Designing Partially Coated Ultrathin Hydrophobic Silica Layer for Highly Conductive and Durable Carbon Nanofiber as Cathode Carbon Support in Polymer Electrolyte Fuel Cells
Authors: Park Jae-Hyun , Hwang Sun-Mi , Kim Aeran , Lim Seongyop , Guim Hwanuk , Won Jonghan , Bae Hyung bin , Park Gu-Gon , Yoon Young-Gi , Yim Sung-Dae , Kim Tae-Young
Published: February 2020

For the last decade, the polymer electrolyte fuel cells (PEFCs) have been recognized as a strong alternative power source instead of the gasoline-powered internal combustion engine due to their high energy conversion efficiency and environmental benignity. Among a number of composition factors, the development of cathode electrode with affordable durability is arguably the most important consideration for maintaining long-term automotive applications because their performances are typically limited by permanently damaged carbon supports and platinum (Pt) loss during abnormal and transient conditions such as very fast potential transient condition and frequent start-up/shutdown procedures. In the carbon corrosion procedures, it is important to have an appropriate strategy that provides means to significantly reduce the carbon corrosion as follows: i) there are fewer water molecules in the vicinity of carbon supports to decrease the carbon corrosion and Pt oxidation formation according to mechanism of electrochemical carbon corrosion; and ii) the spill-over of ∙OH radical from Pt particles should be minimized by avoiding the direct contact between oxidized Pt and carbon surface. Herein, we reported a new strategy to functionalize the graphitized platelet carbon nanofiber (PCNF) surface, which was developed to make an unevenly-coated ultrathin hydrophobic silica layer on PCNF. Subsequently, Pt nanoparticles would be deposited into an empty space between an unevenly-coated silica layers. According to the experimental observation related to the electrochemical reactions, the initial performance of membrane electrode assembly (MEA) based on PCNF composite with 5 wt% silica layer exhibited similar to that for virgin PCNF due to similar HFR values. To the best of our knowledge, its initial cell performance is one of the best among the PCNF composites with silica layer reported in the literature. In addition, the PCNF composite with silica layer showed superior long-term durability compared to the virgin PCNF due to enhanced durability of carbon support and Pt nanoparticles.
Electrochemical Characterization of Sb-Doped SnO2 as Electrocatalyst Support for Electrochemical Energy Conversion Systems
Authors: Hernández Cortés Ramiro de Jesús , Gurrola Mayra Polett , Rivas Gandara Sandra , Chavez Abraham Ulises , Ledesma-García Janet , Arriaga Luis Gerardo
Published: February 2020

Electrochemical energy conversion systems, mainly Unitized Regenerative Fuel Cells (URFC) and Solid Polymer Electrolyzer (SPE), are considered to have a promising future due to the generation of hydrogen in a clean and sustainable way. However, the design of oxygen electrodes is the main limiting factor for an efficient performance. In this matter, most of the studies have been focused in the development of efficient electrocatalyst for the oxygen reduction and water electrolysis reactions, and the use of electrocatalysts supports different from conventional carbon-based materials, which is susceptible of corrosion at the URFC and SPE operation conditions. Corrosion resistance supports, with improved surface area and conductivity, would reduce the electrocatalyst loading,the membrane electrode assembly degradation rate, and the global construction cost of the systems. The present work deals with the synthesis and electrochemical characterization of a Sb – doped SnO2 (ATO) for their potential use as electrocatalyst support in the oxygen electrode in electrochemical energy conversion systems. The synthesis of the support was performed by the sol –gel technique with a surface area modification with dodecylamine as surfactant followed by a thermal treatment. Electrochemical stability was evaluated by cyclic voltammetry (CV) with 250, 400 and 500 cycles in a wide range (0 – 2.0 V vs ENH), while the chronoamperometry (CA) was evaluated at high anodic potential (1.8 V vs ENH) in a continuous period of time of 5 h and 8 h. The results revealed that the Sb doped SnO2 support, present good electrical properties and electrochemical stability at a higher potential of 1.8 V vs. NHE in the presence of O2, as compared to other carbon-based and commercial sub-stoichiometric titanium oxide (Ebonex ®) supports.