bluuebunny/crossref_metadata_2025 huggingface dataset:
Revealing the Impact of Anions in Lithium Oxygen Batteries
Authors: Iliksu Merve , Yang Shuo , Sauer Dirk Uwe
Published: February 2020

Despite their high theoretical capacity, lithium oxygen cells cannot be fully discharged to the limit of their theoretical energy density. The main reason for that is the insoluble and insulating character of the discharge product Li2O2, when it is formed as a thin film form on the cathode, creating the passivation layers, and causing a stop of the charge transport. Furthermore, the discharge/side products can block the cathode’s pores, therefore limiting capacity too. Capacity is also limited by oxygen transport especially at higher current rates. The solubility of oxygen in the electrolyte and the diffusion is important in that case, and can be increased with the right choice of salt.

A big challenge in building lithium oxygen batteries is choosing proper electrolyte for the system, which should be stable against species such as LiO2
-, LiO2, O2-, O2
2-. New combinations are necessary to improve issues such as minimizing electrolyte breakdown and/or enhancing the stability of the battery.

In this work the electrochemical performances are investigated using constant current measurements and cyclic voltammetry of the lithium nitrate and bis(trifluoromethane) sulfonamide lithium salt mixtures in tetragylme. Furthermore, post mortem analysis in the form of Raman Spectroscopy, Scanning Electron Microcopy, and Energy – dispersive X ray Spectroscopy is performed. The contribution of this work is an analysis of the effect of various lithium salts, by maintaining the activity of Li+ but changing the anion. This yields insights into the extent of ion pairing and its effects on the Li-O2 battery system. Higher capacity results are coming from the increased stability and solubility of ion pair species that are formed in the electrolyte between the initial oxygen reduction reaction product (superoxide), O2
- and solvated the Li+.

Figure 1. Constant current first discharge performances of LiNO3 and LiTFSI salt mixture concentrations and Scanning Electron Micrographs (scale 10µm) of their air cathode.

Figure 1
Performance Enhancement in Redox Flow Batteries Using Bismuth Based Catalyst
Authors: Kwon Yongchai , Suharto Yustian , Yang Seungwon , Kim Ki Jae
Published: February 2020

Slow reaction rates of vanadium (V), iron (Fe), chrome (Cr) redox couples are a bottleneck to address for enhancing performance of vanadium and Fe-Cr redox flow battery (VRFB and Fe-Cr RFB) system. For promoting their reaction rates, new catalytic materials based on Bismuth (Bi) are suggested in this study. Reaction reversibility as well as catalytic activity of the catalysts is investigated using cyclic voltammogram (CV) and the results are compared with those of other catalysts. Performances and long term stabilities of VRFB and Fe-Cr RFB using Bi-based catalysts are evaluated by repetitive and cyclic measurements of charge-discharge step. Especially, energy efficiency (EE) and capacity loss rate are mainly inspected to determine superiority of the VRFB and Fe-Cr RFB. Their crystal structure, specific surface area and catalyst morphology are measured by chemical characterizations. The new Bi-based catalysts show high peak current ratio, small peak potential difference and high electron transfer rate constant, confirming that in both catalytic activity and reaction reversibility facets, the Bi-based catalysts play an important role. In terms of charge-discharge curves, VRFB and Fe-Cr RFB including new catalysts indicate high EE, low overpotential and low internal resistance. The results are attributed to role of Bi that activates Fe2+/Fe3
+, Cr2+/Cr3
+ and V4+/V5
+  redox reactions. Indeed, adoption of the Bi-based catalysts lead to improvement in performances and long term stabilities of VRFB and Fe-Cr RFB.
Single Wall Carbon Nanotube Modified with Nano Size Metal Oxides for High-Performance Cathode in Li-O2 Rechargeable Batteries
Authors: Jang Il-Chan , Ishihara Tatsumi
Published: February 2020

Li-O2 batteries have a big potential for the application of future electrochemical power sources because of their much larger energy density than that of conventional Li ion battery. However, rechargeable Li-O2 batteries are still facing many challenges including large overpotential, low round trip efficiency, low power capability, and poor cycle stability. All these poor electrochemical performances are related with poor reversibility of air electrode, which can be improved by employing sophisticated and active cathode [1]. As confirmed in our early study [2], a mesoporous oxide can virtually reduce the overpotential and enhance the cycle efficiency with abundant active sites. In addition, as a carbon substrate, a CNT has high chemical and thermal stability, high tensile strength and excellent electrical conductivity resulting from their unique structures. Discharge capacity of 1200 mAh/g was achieved on Li-O2 battery using CNT for cathode, however, because of high charge potential, cycle performance was poor. In this study, therefore, we introduce combination of single wall carbon nanotubes (SWCNT) and mesoporous metal oxides as a cathode for Li-O2 batteries. It was found that discharge capacity was decreased by loading mesoporous MnO2, cycle stability was much increased, in particular, co-loading of Co3O4 and Cr2O3 shows much superior cycle stability and discharge capacity was sustained up to 100 cycles. Characterization techniques ranging from, electron microscopy, surface analysis have been applied for metal oxides. Large porosity formed in SWCNT electrode seems to be one reason for large discharge capacity and cycle stability.

References

[1] Z. Ma, X. Yuan, L. Li, Z.F. Ma, D. P. Wilkinson, L .Zhang, J. Zhang, Energy & Environmental Science, 8, 2044 (2015).

[2] A. K. Thapa, Y. Hidaka, H. Hagiwara, S. Ida, T. Ishihara, J. Electrochem. Soc., 158, A1483(2011)
Synthesis of Graphitic Ordered Mesoporous Carbon for High-Performance of Lithium-Sulfur Battery
Authors: Kim Min-Seop , Kim Woong , Cho Won Il
Published: February 2020

Recently, the lithium-sulfur (Li-S) battery system has been estimated as the most promising candidate for next-generation battery system due to its high theoretical capacity, relatively low cost of sulfur, and environmental-friendly. However, Li-S battery system has some chronic issues for further development and commercialization. First major problem is an insulating property of elemental sulfur as an active material. Second is so-called “Shuttle phenomenon” caused by polysulfides dissolution in electrolyte during the cycling. To cope with these problems, we present here the strategy of employing highly graphitic ordered mesoporous carbon (GOMC) for cathode material. This GOMC enhances the rate capability with its graphitic structure and also increases the Coulombic efficiency by prohibiting the dissolution of polysulfide species.
the Role of Ceramic Filler in Microporous Gel Electrolytes for Sodium Ion Batteries
Authors: Kim Seokwoo , Nguyen Ngoc Anh , Kim Kyuman , Ryou Myung-Hyun , Lee YongMin
Published: February 2020

Abstract

Due to the abundance in nature and the low price of sodium ions, sodium ion batteries have been considered as the promising candidate for the next generation high-capacity rechargeable battery system.

Herein, we investigate the effect of ceramic filler, alumina (Al2O3), in gel polymer electrolytes based on poly(vinylidenefluoride-co-hexafluoropropylene) porous membrane prepared through a simple phase separation process. Ceramic fillers improved not only the mechanical properties but also the electrochemical stability, resulting better cycle performance during electrochemical tests. We believe these results are attributable to the enlarged surface area and the improved wetting property of gel polymer electrolyte to liquid electrolyte, resulting larger amount of liquid electrolyte uptake. The surface and cross section structure images of composite membranes were investigated by field-emission scanning electron microscope (SEM) as a function of Al2O3 contents. Ionic conductivity of composite gel polymer electrolytes was measured using an impedance analyzer (VSP). The uptake amount of liquid electrolyte was determined by measuring the weight changes of composite gel polymer electrolytes. The unit cells employing the composite gel polymer electrolytes achieved significant improvements in rate capability.

 

Acknowledgements

This work was supported by the Human Resource Training Program for Regional Innovation and Creativity through the Ministry of Education and National Research Foundation of Korea (NRF-2014H1C1A1066977)

Refernces

Y.Q. Yang et al. / Solid State Ionics 269 (2015) 1 7 Y.Q. Yang et al. / Solid State Ionics 269 (2015) 1 7

Bella Federico et al. / ChemsusChem 8.21 (2015): 3668-3676.

Gao Hongcai et al. / Advanced Energy Materials 5.9 (2015).
A Simple Approach of Electrolyte Development for Magnesium Ion Battery
Authors: Sa Niya , Wang Hao , Key Baris , Brombosz Scott M , Burrell Anthony , Vaughey John T.
Published: February 2020

Abundance of the magnesium element in the earth's crust and the safety features of Mg metal have attracted extensive attention for the development of rechargeable Mg battery. However, major roadblock for magnesium ion battery development is the availability of an electrolyte that can deposit Mg reversibly. Before the successful invention of a prototype Mg ion battery, optimization of the Mg electrolyte performance is necessary. Work presented here includes a new, non-halogen contained Mg electrolyte that can plate and strip Mg reversibly. Specifically, electrochemical evaluation of this new non-aqueous Mg electrolyte will be discussed.

Figure 1
Hierarchical Ru and RuO2 Foams with Superior Performance for Rechargeable Lithium Oxygen Battery Cathodes
Authors: Suk Jungdon , Kwak Kyoung Hwan , Kang Yongku
Published: February 2020

Synthesis and structure design of cathode materials with superior catalytic activity is still major challenge for rechargeable lithium-oxygen batteries. Among many cathode materials, carbons are often used because they help achieve high discharge capacities and good ORR performance. However, most lithium-oxygen batteries containing carbon electrodes suffer from a low round-trip efficiency, low rate capability, a poor cycle life, and electrolyte instability. In this poster, we report a binder- and carbon-free, 3D porous Ru- and RuO2-foam cathode for lithium-oxygen batteries. The cathode was simply fabricated by three-step process; co-electrodeposition, electrochemical dealloying and heat treatment process. Both 3D porous Ru- and RuO2-foams have lots of cavity and pits which provide a large surface area for catalytic sites and buffer spaces for the volume stress by the formation/decomposition of Li2O2 during the cycling process. Moreover, cathodes made of Ru- and RuO2- foam can provide high catalytic activities, short ion diffusion length and channels for rapid transport of oxygen and electrolyte. The hierarchically dendritic cathodes without carbon and binder present low charge/discharge overpotential, remarkable cyclability, good oxygen efficient and reduced irreversible formation form electrolyte decomposition. We systematically investigated the reversibility and cyclability of a lithium-oxygen battery using the 3D porous Ru- and RuO2-foam cathode using scanning electron microscopy (SEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), in-situ Differential Electrochemical Mass Spectrometry (DEMS) and FT-IR spectroscopy. The results using the 3D porous nanostructured electrodes in our study represent a promising approach for high-performance electrodes which are compatible with scaled-up manufacturing process for next-generation lithium- air batteries due to their simple and rapid fabrication process.

1. Fujun Li, Tao Zhang, Haoshen Zhou, Energy Environ. Sci. 6, 1125-1141 (2013) 2. Fujun Li, Dai-Ming Tang, Yong Chen, Dmitri Golberg, Hirokazu Kitaura, Tao Zhang, Atsuo Yamada, and Haoshen Zhou, Nano letter, 13, 4702-4707 (2013) 3. Fujun Li, Dai-Ming Tang, Zelang Jian, Dequan Liu, Dmitri Golberg, Atsuo Yamada, Haoshen Zhou, Adv. Mater., 26, 4659-4664 (2014) 4. Myung-Gi Jeong, Kai Zhuo, Serhiy Cherevko, Woo-Jae Kim, Chan-Hwa Chung, J. of Power Sources, 244, 806-811 (2013)
A Renewable Anthraquinone Derivative As Organic Anode Materials for Sodium-Ion Batteries
Authors: Wu Dabei , Huang Yunhui , Hu Xianluo
Published: February 2020

Most renewable energy, like wind energy and solar energy, is dispersive and discontinuous because of energy distribution and geographic factors. Therefore, we need energy storage devices to collect and store them. Na-ion batteries are suitable for large-scale energy storage considering abundant natural resources.1 Here, we report a renewable anthraquinone derivative as organic anode materials for sodium-ion batteries. The alizarin is extracted from the roots of madder. Results show that the first discharge capacity is as high as ~700 mAh/g and the capacity keeps at ~150 mAh/g after continuous discharge/charge cycles, as shown in Figure 1. The different status of the fully and partially discharged/charged electrodes was investigated, and the related Li-cycling mechanism was also explored.

References:

1. Slater, M. D.; Kim, D.; Lee, E.; Johnson, C. S., Sodium-Ion Batteries. Advanced Functional Materials 2013, 23 (8), 947-958.

Figure 1
Spinel NiCo2O4-Deposited CNT Bucky Paper As a Cathode for Rechargeable Li-O2 Battery
Authors: Jung Kyu-Nam , Lee Jong-Won
Published: February 2020

There has been a great interest in the development of rechargeable batteries with high energy storage capability due to an increasing demand for electric vehicles (EVs) with driving ranges comparable to those of gasoline-powered vehicles. Among various types of batteries under development, a Li–oxygen(O2) battery delivers the highest theoretical energy density, thus, it is considered a promising energy storage technology for EV applications [1]. Cathode (oxygen electrode) is the key component of Li–O2 battery, since the major battery reactions i.e., oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) occur at its surface. However, low round-trip efficiency, poor reversibility and poor power capability are the major challenges faced by the cathodes of the Li–O2 battery [2].

Although the carbon has been generally considered as a good cathode material in Li-O2 batteries because of its advantages such as good chemical stability, high conductivity and versatile porosity, however, it may suffer from the corrosion/oxidation at high potentials in the charging process and promote the electrolyte decomposition accompanying various side reactions during cycling. Therefore, it is strongly required to find out the alternative cathodes to circumvent side reactions involving carbon based materials. To resolve this problem, one possible solution is to suppress the direct exposure of carbon surface to the aprotic electrolyte by uniform coating of non-carbon material on the carbon surface.

In the present work, we report spinel NiCo2O4-deposited CNT (carbon nanotube) bucky paper as a cathode for Li-O2 batteries. To passivate the surface of CNT buckypaper to be attacked by Li2O2 and super radicals, the CNT bucky paper cathode was uniformly coated by metal-oxide (NiCo2O4) layer using simple hydrothermal method. The structural properties of the oxide-deposited CNT cathode are characterized and the electrochemical performances of Li-O2 battery constructed with that cathode are evaluated. The oxide-deposited CNT cathode shows high specific capacities and remarkably reduced charge potentials (in comparison with a carbon-only cathode) as well as excellent cyclability, which suggests that the deposited oxide layer on the surface of CNT effectively reduces the amount of carbonates generated on the surface of carbon.

Reference

[1] A. C. Luntz, B. D. McCloskey, Chem. Rev., 114 (2014) 11721.

[2] I. Landa-Medrano, R. Pinedo, N. Ortiz-Vitoriano, I. R. Larramendi, T. Rojo, ChemSusChem, 8 (2015) 3932.
Towards p-Type Conductivity in SnO2 Nanocrystals through Li Doping and Its Applications in Porous Diodes for Room Temperature Chlorine Gas Detection
Authors: Chaparadza Allen , Rananavare Shankar
Published: February 2020

This work examined electrical transport properties and Li doping in SnO2 synthesized by the sol–gel method. Solid-state 7Li-NMR line shapes revealed that Li ions occupy two distinct sites with differing dynamic mobilities. The chemical exchange rate between the two sites is, however, too slow for detection on the NMR timescale. Compressed nanoparticulate films of this doped semiconductor exhibited a positive Seebeck coefficient implying a p-type conductivity. A variable-temperature direct current conductivity, over a 25–350 °C temperature range, followed an Efros–Shklovskii variable range hopping (ES-VRH) conduction mechanism (ln(ρ) versus T
−1/2) at temperatures below 100 °C with a crossover to 2D Mott variable range hopping (M-VRH) (ln(ρ) versus T
−1/3) conduction at temperatures above 250 °C. In a transition region between these two limiting behaviors, direct current resistivity exhibited an anomalous temperature-independent plateau. We suggest that its origin may lie in a carrier inversion phenomenon wherein the majority carriers switch from holes to electrons due to Li ion expulsion from the crystalline core and creation of oxygen vacancies generated by loss of oxygen at elevated temperatures. Using a compression technique, porous diodes consisting of n-type (antimony doped SnO2) and the p-type (lithium-doped) nano-particulate films were prepared. Typical current-voltage curves of such devices resembled the behavior of a typical diode but for one key difference; owing to the porosity of the film, areas near the p-n interface and the p- and n-regions are accessible to gaseous analytes. This access is not possible in conventional diodes fabricated through contemporary planar technology. The gas sensing properties of the diodes were investigated by using Cl2, Br2, HCl, NO, NO2, CHCl3, NH3 and H2. Of all the gases tested, the sensor had very good sensitivity to Cl2 and had a response of 80 at 400 ppb of Cl2. The response time of the sensor was ~30 s at room temperature but the recovery time was temperature dependent. At room temperature the recovery time was 80s after 400 ppb chlorine exposure. The sensors were also found to recover quickly (~ 30 s) when the junctions were biased. Reverse biasing the diode provides a controllable band-bending at a p-n junction that could influence the electron-transfer rates from the adsorbates which create intra-band localized states. As a result reverse biasing can provide a means of desorbing the analyzed species. This approach eliminates the requirement to remove adsorbates by elevating the sensor temperature and hence improves on the energy efficiency of these types of sensors.
(Invited) Rapid Formation of Single-Cell Pairs for Hybrid Cells
Authors: Yasukawa Tomoyuki , Mizutani Fumio
Published: February 2020

Dielectrophoresis (DEP) has been used as a manipulation tool for a separation, sorting and patterning of particles and cells. We have used negative-DEP (n-DEP) which directs particles and cells to form line patterns with particles and cells rapidly toward the localized positions with relative weak electric fields. In this presentation, a microwell array electrode was used to produce vertical pairs with two different types of cells by positive-DEP (p-DEP).

A microwell array (250,000 wells, 500 × 500) was fabricated on a substrate with indium tin oxide (ITO) layer by coventional photolithography. Microwells were designed in 16 μm width and 25 μm depth. Another ITO substrate was mounted on the microwell array via 30 μm thick polyester film to form a fluidic channel.

Mouse myeloma cells (4.0 × 107cells/mL, 12 μm diameter) stained in blue with Hoechst 33342 were introduced into the fluidic channel. AC voltage (1.0 MHz, 10 Vpp) was immediately applied between the upper ITO and lower ITO with microwell array to guide cells in individual microwells by p-DEP. On applying the AC voltage, the dispersed cells immediately, i.e., within 1 s, stayed at positions with microwells. In the microwells trapped with two cells, cells in the top component were removed by the fluidic flow, but cells in the bottom component were retained in the microwells because the fluidic flow could not remove cells from microwells with a depth of 25 μm, i.e., twice the cell diameter or more. These results clearly indicate that the cell array could be formed on the microwell array electrode easily and rapidly by p-DEP.

K562 cells (15 μm diameter) stained in green with 5-(and-6)-carboxyfluoresein diacetate succinimidyl ester (CFDA SE) were also guided into microwells occupied with myeloma cells in blue by p-DEP. Myeloma cells in blue and K562 cells in green were successively trapped into microwells by p-DEP. The presence of two cells is not particularly clear in the optical image. In contrast, both blue and green signals which are indicated the presence of myeloma cells and K562 cells are clearly observed from the individual microwells. These results strongly indicated that two different types of cells are vertically aligned in microwells to form single-cell pairs. We can obtain pairs of different cells within 1 min with the pairing efficiency of approximately 68 %. The vertical alignment of cell pairs would be a distinct advantage for producing couplets by cell fusion using electric pulse fields generated between the upper electrode and the lower microwell array electrode, which were used for the cell pairing by p-DEP. The array of two different types of cells can be easily and rapidly formed using the simple device with a p-DEP process.

Figure 1
Performance of Whole-Cell Electrochemical Biosensor Using Integrated Microbes/Si Nano-Forest Structure
Authors: Mintz Hemed Nofar , Yoetz-Kopelman Tal , Convertino Annalisa , Shacham-Diamand Yosi
Published: February 2020

Integrating microbial cells on Si nano-forest is a new structure combines whole cell biosensors with a functional nanostructured electrode. Such structure produces a unique electrochemical impedance spectrum in response to charged immobilized microbes. That signal, which is observed by both Nyquist diagram and the Bode plot was investigate in the current research.   

Microbial biosensors are widely used for toxicity measurements, food monitoring e.g. sensing of alcohol, glucose, or fatty acids, environmental monitoring, monitoring of microbial growth rate, and biocide measurements. Microbial cells can generate a widespread selective responses to chemical and biological reactions. Utilization of this advantage can yield specific sensors and allay one of the major challenges of chemical and biological sensor design. Moreover, the use of lives cells allows for label-less, non-destructive real-time monitoring of the biological reactions as they develop, with no require for preparatory and analytical steps such as staining or hybridization. 

Bacterial cells were genetically engineered to display ZZ protein on the surface of their cell (a kind gift from Prof. Benhar lab). Z domain is a small engineered protein of 58 amino acids, analog of Protein A B domain, originally developed as an affinity-purification ligand. ZZ fragments exhibit high affinity (~10-8M) to Fc region of human IgGs, higher than the affinity of a single Z domain. Each Z domain interact with two distinct sites of the Fc region. Expression and display of Z domain in E.coli was demonstrated before. 

The combination of nanostructures, such as Si nanowires (SiNWs), with bacterial cells offers new and unique opportunities to develop novel biosensors. Usually in biosensors, microbial cell immobilized to a planar electrode, consequently part of the displayed charge on the surface of the cell is screened by the electrode itself. This screening effect is decreasing while using SiNWs structure to bind the microbial cells.  

We present a study of highly dense, disordered, and randomly oriented ensemble, i.e. Si nano-forest. This Si nanostructured was deposited using relatively low cost and scalable techniques, such as Plasma Enhanced Chemical Vapor Deposition (PECVD), at low temperature (below 350°C); this enables deposition on various substrates including flexible polymeric substrates. Si nano-forest were functionalized using rabbit anti mouse IgG as binding receptor for ZZ protein. EIS measurements were performed, at the range of 0.1 Hz to 200 kHz, in phosphate buffer saline (PBS) solution using potentiostat/galvanostat (VSP®, BioLogic science instruments Ltd.). Modeling was preformed using EC-LAB software. Our results confirm that Si nano-forest electrodes can serve as a sensitive and specific whole cell biosensor.
Development of Evaluation System of β-secretase Activity by Using Orientated Immobilizing Recombinant β-secretase
Authors: Iida Yasuhiro , Adachi Minoru , Shiraishi Yuki , Yamaguchi Jyunichi
Published: February 2020

Alzheimer's disease (AD) is one of the type of dementia and the numbers of the patients has been increasing in the world. However, there are no effective reagents for the disease because the cause of AD is not well-known. The neuropathological diagnosis of AD is decided upon the detection of amyloid plaques which made by insoluble amyloid. It is known that the amyloid is produced by β-secretase and γ-secretase which catalyze the amyloid precursor peptide. The β-Secretase is known as a one of a key enzyme for development of therapeutic agent to AD because the enzyme activity is specifically high in AD patients. All the conventional β-secretase inhibitors are substrate analogs, it means that those inhibitors are competitive and reversible inhibitor. Therefore, a non competitive enzyme inhibitor of β-secretase will be able to be a novel reagent as an anti-AD. In the previous study, we already developed the system to evaluate properties of the inhibitors whether its effect is reversible or irreversible. In this study, we developed evaluation system for activity of β-secretase by using immobilized recombinant β-secretase in combination with a FIA (Flow Injection Analysis) system. On the other hand, conventional method for enzyme immobilization cannot control enzyme orientation. Hence we investigated orientation of immobilized enzyme by using specific binding of biotin and streptavidin. And we tried to miniaturize the system to reduce assay time and increase the sensitivity. Furthermore, we applied the system to evaluate the property of conventional inhibitor.
Amyloid β Detection with Integrative Chip for Alzheimer Desease
Authors: Lee Jeong Hoon , Yoo Yong Kyoung , Hwang Kyo Seon
Published: February 2020

To enhance sensitivity and detection limit, may research have been reported both with new materials and hybridization of two different devices/functions. Recently, due to high preconcentrator factor and simple method, the interest of ion concentration polarization (ICP) for sensor has been increasingly recognized. Here, we report ion concentration polarization based preconcentrator integrated with electrical biosensor to overcome low affinity of low concentration. We achieve approximately 25-fold concentrated sample on IMEs sensor with ICP preconcentrator. Utilizing ICP preconcentrator integrated IMEs sensor, we are able to detect below 22.15 fM Aβ with 3.2-fold higher sensitivity of impedance change. Moreover, detection limit of Aβ has also improved under concentration of 2.215 fM with ICP preconcentrator integrated IMEs sensor. From these results show our newly proposed ICP preconcentrator integrated IMEs sensor was better than conventional method for detection and quantification of low Aβ level and affinity. Also, a unifying technique between preconcentration and sensor platform is provide new opportunities with analytical sensitivity and detection limit within a few minutes.
Highly Swellable Hydrogel Electrolyte for Metal Air Battery
Authors: Yamada Naoya , Ahmed Kumkum , Wada Masato , Khosla Ajit , Furukawa Hidemitsu
Published: February 2020

Gels have three-dimensional cross-linked polymer network, which can extensively swell in water or hydrophilic solvents depending on their structure. High swelling property of the hydrogels can be very beneficial to use them as electrolyte material for battery application. Among the energy storage devices like lithium-ion, nickel-cadmium, and lead-acid batteries, metal-air batteries have the advantages of higher capacity and energy density. In this work, our aim is to use highly swellable hydrogel as electrolyte, Aluminium as metal anode and Carbon-Manganese composite material as cathode. Gel polymer electrolyte is a well-studied and most widespread field for Li-ion batteries and electrochemical devices as they offer many advantages such as no internal shorting, leakage of electrolytes and non-combustible reaction products at the electrode surface existing in the liquid electrolytes. But high cost, low life and capacity, poor ionic conductivity and difficult processing are the common drawbacks of gel polymer electrolytes. To overcome these problems we approached in a very fundamental way of using common electrolyte solutions like NaCl, KCl, NaOH, KOH etc., which will be absorbed by the neutral monomeric N, N, Dimethylacrylamide (DMAAm) hydrogel which can be very low cost and easy to re-swell whenever electrolyte goes down. DMAAm hydrogel was synthesized by single step photopolymerization method in presence of initiator Benzophenon (BzPh) and crosslinker N,N'-Methylenebisacrylamide (MBAA). Prepared gels were swelled in different concentration of aqueous electrolyte solutions to study their swelling, mechanical and electrochemical behavior. As battery performance depends on both the electrolyte and electrode, so we also investigated the morphology of the electrode we used. Finally the battery performance and critical issues are taken into account to make the current method practically functional. This work can make real contribution to the field of metal air battery and develop new viewpoints in the field of gel electrolyte materials.
Optimization of GaN-Based HEMTs for Chemical Sensing: A Simulation Study
Authors: Sciullo Madeline , Choudhury Mohua , Patrick Erin , Law Mark E
Published: February 2020

Gallium Nitride (GaN)-based High Electron Mobility Transistors (HEMT)s have been shown to be a viable solution for a myriad of chemical and biological sensing applications (e.g., pH sensing, prostate cancer, and breast cancer detection). Modulation of the conducting channel in response to charge adsorbed on the un-metalized gate contact provides a sensitive mechanism for detection of chemical species. Despite numerous experimental studies on these devices, general design considerations such as the role of bias conditions or length-scales on the device operation have not been fully explored. This work makes use of TCAD simulation to identify key parameters for sensor optimization.

Simulation of the general case of one reacting species adsorbing to the open-gate area of an AlGaN/GaN HEMT is performed. Our simulation framework –the Florida Object Oriented Device Simulator (FLOODS)– is specifically suited for III-V device simulation and is capable of self-consistent, fully-coupled simulation of reaction-dependent physics at the electrolyte/semiconductor interface. Simulation results in Figure 1.a show a linear trend of increasing sensitivity with gate length over a range of 0.1 to 1.5 μm. This result predicts an obvious increase in sensitivity with an increase in active sensing area. It is also shown in Figure 1.b, for the first time, how the linearity of the device sensitivity is highly dependent on gate length, or active surface area. This work delves in to the physical mechanisms that play a role in sensor parameters such as linearity and identifies optimum bias conditions for single-ion chemical sensors, in general.

Figure 1. Simulation results for a bias condition of Vds=4V and unbiased gate. (a). Peak sensitivity as a function of gate length. (b). Sensitivity as a function of ion concentration. The linearity of device is dependent on gate length.

Figure 1
Preparation of Li4Ti5O12 Nanosheets/Carbon Nanotube Composites and Application of Anode Materials for Lithium-Ion Batteries
Authors: Diao Guowang , Zhang Pengfei , Chen Ming
Published: February 2020

ABSTRACT:

Li4Ti5O12
nanosheets (LTO NSs)/carbon nanotubes (CNTs) composites are synthesized using a facile, reproducible, and scalable strategy. In the hydrothermal process, the introduction of CNTs significantly improves the rate performance of LTO NSs. The incorporation of CNTs into the LTO NSs forms a delicate conductive network for rapid electron and lithium ions transport, resulting in excellent rate performance and superior cycling performance. LTO NSs/7.5%-CNTs composites show the highest reversible capacity and high-rate capability (a reversible capability of 157, 145, 132, 118, and 105 mA h g-1 at 1, 2, 3, 4, 5 A g-1, respectively) with good cycling performance (approximate 6.9% capacity loss after 1000 cycles at 2 A g-1 with a capacity retention of 135 mA h g-1), which is apparently larger than pristine LTO NSs. The significantly improved rate capability and cycling performance of the LTO NSs/CNTs composites are mainly attributed to their the lower polarization of potential difference, the larger diffusion coefficient of lithium ion and smaller charge-transfer resistance than pure LTO NSs.

Keywords: Lithium titanate nanosheets; Carbon nanotubes; Rate performance; Lithium ion diffusion; Lithium ion batteries

References

[1] Y.-Q. Wang, L. Gu, Y.-G. Guo, H. Li, X.-Q. He, S. Tsukimoto, Y. Ikuhara, L.-J. Wan, Rutile-TiO2 Nanocoating for a High-Rate Li4Ti5O12 Anode of a Lithium-Ion Battery, J. Am. Chem. Soc. 134 (2012) 7874-7879.

[2] G. Xu, W. Li, L. Yang, X. Wei, J. Ding, J. Zhong, P. Chu, Highly-crystalline ultrathin Li4Ti5O12 nanosheets decorated with silver nanocrystals as a high-performance anode material for lithium ion batteries, J. Power Sources 276 (2015) 247-254.

[3] B. Li, C. Han, Y.-B. He, C. Yang, H. Du, Q.-H. Yang, F. Kang, Facile synthesis of Li4Ti5O12/C composite with super rate performance, Energy Environ. Sci. 5 (2012) 9595-9602.

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21273195, 21511140282), a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions. The work was also sponsored by Qing Lan Project of Higher Learning Institutions in Jiangsu Province, the support of high-end talent plan of Yangzhou university, and Jiangsu Key Laboratory of Environmental Material and Environmental Engineering (K11032). The authors also acknowledge the Testing Center of Yangzhou University for SEM, TEM, XRD, and Raman experiments.
Nano-Biosensors: An Advanced and Essential Tool in Monitoring Microcystins in Water
Authors: Vogiazi Vasileia , Zhang Lu , Zhao Daoli , Alvarez Noe , Chae Soryong , Sagle Laura , Heineman William R. , Shanov Vesselin N. , Papautsky Ian , Dionysiou Dionysios D.
Published: February 2020

Freshwater contamination during extensive algae blooms with their cyanotoxins represents a significant global concern for public health. In 2014, algae blooms have significantly affected drinking water supply in the Toledo (OH, USA). Due to similar threatening incidents, the U.S. Environmental Protection Agency (USEPA) was urged to release a ten-day drinking water health advisory for cyanotoxins. In June 2015, USEPA advised very low concentrations for children consumption that may reach the 0.3 μg/L for microcystin-LR. In the fall 2015, Ohio River contamination exceeded the 650 miles along the river. These incidents along with the strictness of advisories and regulations urge the development of a portable, simple and highly selective monitoring tool to measure the lowest possible microcystins’ concentration in various water sources. Our team utilize attractive InterDigitaded array (IDA) gold and graphene-based electrodes to demonstrate their capabilities in detecting microcystins in drinking water. In this study, electrochemical nano-biosensors based on three dimensional (3D) graphene were made, functionalized and characterized. The novel 3D graphene paper exhibits high electrical conductivity, and large specific area, which ensures high charge-transfer rate and good sensitivity for microcystin detection. Cyclic voltammetry and impedance spectroscopy were used to explore the interfacial phenomena of gold IDA and the 3D graphene biosensors.
Fabrication of Symmetrical La0.7Ca0.3Cr0.8Mn0.2O3-
d Electrode Scaffold-Type Micro Tubular Solid Oxide Fuel Cells By Electrophoretic Deposition
Authors: Lee Sang-Hun , Park Yoon-Tae , Park Jae-Woo , Lee Ki-Tae
Published: February 2020

Solid oxide fuel cells (SOFCs) have the highest energy conversion efficiency among various fuel cell types. SOFCs can be divided into two categories according to their cell design: planner and tubular type. Tubular SOFCs have many advantages in terms of good mechanical strength, easy sealing, and simple stacking process.

 Meanwhile, electrophoretic deposition (EPD) is very useful technique to deposit thin or thick layers due to easy layer thickness control by voltage and time. When a dc electric field is applied to the carbon rod in the slurry, the charging agent carries the particles to a substrate. One of major advantages of EPD is to fabricate multi-layer structure at the same time.

 In this study, symmetrical La0.7Ca0.3Cr0.8Mn0.2O3-
δ(LCCM) electrode scaffold-type micro tubular SOFCs with the configuration of LCCM-YSZ anode // YSZ electrolyte // LCCM-YSZ cathode have been fabricated by EPD process. LCCM is considered as promising symmetrical electrode because it is very stable in both oxidizing and reducing atmosphere. The microstructure of the symmetrical electrode was controlled by the amount of pore former (PMMA). LCCM-YSZ electrode slurry for highly porous microstructure with uniform pore distribution was obtained with 40 vol.% PMMA, 2.5 wt.% polyvinyl butyral (PVB), 100 ml anhydrous ethanol, and 3 wt.% charging agent (polyethyleneimine). YSZ electrolyte slurry with highly dense microstructure was prepared with polyvinyl butyral (PVB), 100 ml anhydrous ethanol, and 5 wt.% charging agent (phosphate ester). After weighing of each slurry, ball-milling process was performed for 24 hour to obtain well-dispersed and uniform slurry. Carbon rod was deposited by LCCM-YSZ anode slurry, YSZ electrolyte slurry, and LCCM-YSZ cathode slurry in order. Deposition condition affected the microstructure and on thickness of each layers. LCCM-YSZ anode had thick layer for supporting the single cell with the deposition condition of the applied voltage of 20 V for 100 second. YSZ electrolyte was deposited on anode with the deposition condition of the applied voltage of 20 V for 20 second. At last, LCCM-YSZ electrode was deposited on electrolyte with the deposition condition of the applied voltage of 20 V for 20 second. After deposition of all layers by EPD, the single cell was co-filed at 1400 °C for 5 hour.

 Various processing conditions such as amount of charging agent, applied voltage, deposition time and sintering temperature were investigated. Stoichiometry amount of co-catalysts such as Pd or Co-Ni-Mo for better performance were impregnated into both sides of the LCCM scaffold by a glycine mediated solution impregnation method. Finally, the single cell performances of the fabricated LCCM symmetrical scaffold-type micro tubular SOFCs were evaluated in the temperature range of 600-800°C. Additionally thermal shock and redox cycling tests have been carried out.
Facile Synthesis and Electrochemical Investigation of Na0.67Mn0.65Fe0.20Ni0.15O2: A Positive Electrode Material for Na-Ion Batteries
Authors: Kishore Brij , Viswanatha R , Venkatesh G , Munichandraiah N
Published: February 2020

Research activities on Na-ion batteries have become intensive in recent years, as they are considered as economical alternatives to Li-ion batteries.1,2 Although, the use of small size Li-ion batteries is now wide spread, their range of applications is expected to increase in larger sizes for applications such as electric vehicles in future. One of the major concerns for expansion of Li-ion batteries in large sizes is the limited and unevenly distributed global resources of Li and hence its high cost. As the sources of Na are distributed over the globe in plentiful and being significantly cheaper than Li, research and development activities are now diverted towards Na-ion batteries.

Among several cathode materials investigated for rechargeable Na-ion batteries, Na0.67Mn0.65Fe0.20Ni0.15O2 is reported to be a promising material.3 Convenient method of synthesis is one of the key issues in deciding potential use of an electrode material in general. In the present study, a low temperature self-combustion method is employed to prepare Na0.67Mn0.65Fe0.20Ni0.15O2. An aqueous solution consisting of stoichiometric quantities of NaNO3, Mn(NO3)2.4H2O, Fe(NO3)2.9H2O and Ni(NO3)2.6H2O is prepared and sucrose is dissolved as the fuel. The mixed solution is slowly heated to 130 °C, where the fuel ignites and produces a black residue within a few minutes. The residue is heated at 800 °C for 6 h to produce well crystalline phase of Na0.67Mn0.65Fe0.20Ni0.15O2. The material is characterized by physicochemical techniques. For the electrochemical studies, CR2032 coin cells are assembled using Na foil as the counter cum reference electrode in an electrolyte of 1 M NaPF6 dissolved in ethylene carbonate and propylene carbonate (1:1 by volume).

When the cells are cycled at a current density of 35 mA g-1, a specific discharge capacity of 178 mAh g-1 is obtained with coulombic efficiency close to 100 %, initially. The capacity decreases to 127 mAh g-1 after 50 cycles which indicates capacity retention of 72% over 50 cycling. The decay in the capacity is studied with the help of electrochemical impedance spectroscopy. Cyclic voltammogram and rate capability experiments are also carried out for detailed study of the material. These results will be presented.

References:

 S. W. Kim, D. H. Seo, X. Ma, G. Ceder, and K. Kang, Adv. Energy Mater., 2, 710 (2012).

 V. Palomares, P. Serras, I. Villaluenga, K. B. Hueso, J. C. Gonzalez, and T. Rojo Energy Environ. Sci., 5, 5884 (2012).

 D. Yuan, X. Hu, J, Qian, F. Pei, F. Wu, R. Mao, X. Ai, H. Yang and Y. Cao, Electrochimica Acta, 116, 300 (2014).

Figure 1
500 Hour Investigation of Electroless Ni-Plated AISI 441 Steel for Solid Oxide Fuel Cell Interconnect Applications Under Operating Conditions
Authors: Ryter John , Amendola Roberta , McCleary Madisen , Gannon Paul , Shong Wei-Ja , Piccardo Paolo , Spotorno Roberto
Published: February 2020

Solid Oxide Fuel Cells (SOFCs) are high-temperature (600-800°C) electrochemical devices that produce heat and electricity by oxidizing hydrogen or short chain hydrocarbon fuels. Due to their high efficiency, fuel flexibility, and low emissions, SOFCs have gained popularity as a method of both large- and small-scale power production. In planar SOFC technology, individual cells are stacked in electrical series using ferritic stainless steel interconnects (ICs), which separate the fuel (anode) and oxidant (cathode) chambers, facilitate gas distribution, and provide mechanical support. The ICs are simultaneously exposed to the fuel (H2) on one side and the oxidant (air) on the other, known as a “dual atmosphere exposure.” Recent advances in SOFC technology have allowed ferritic stainless steels (FSSs) to replace the cost-prohibitive ceramic IC components that were previously used. However, FSSs experience accelerated and/or anomalous corrosion in dual atmosphere environments (relative to single atmosphere exposure – e.g., air only) that leads to SOFC performance degradation. In this study, electroless Ni-plated FSS AISI 441 was evaluated under standard operating conditions, namely 700°C dual atmosphere with and without a current flow of 0.5 A for 500 hours. Morphology of the surfaces and cross sections of each sample were analyzed using a Field Emission Scanning Electron Microscope (FE-SEM) and the composition was assessed using Energy Dispersive X-Ray Spectroscopy (EDX). Anomalous and accelerated oxidation were observed with and without current flow involving massive outward iron diffusion phenomena, as well as inward diffusion of nickel plating. A layered oxide structure was found with and without current flow; however, substantial differences in elemental distribution throughout these layers were observed. These findings, along with mechanism hypotheses, will be presented and discussed in the context of developing durable interconnects for long-term high-performance SOFC systems.

Figure 1: EDX linescan of the anode side (exposed to hydrogen) of Electroless Ni-plated AISI 441 cross sections after 500 hours of exposure at 700°C with current flow of 0.5 A (A) and without current flow (B)

Figure 1
Multi-Scale Modeling of Lithium-Ion Batteries
Authors: Gwak Geonhui , Ju Hyunchul
Published: February 2020

In this study, we present a three-dimensional (3-D), multi-scale, multi-physics lithium-ion battery (LIB) model wherein a mesoscale spherical particle model is applied to an electrode particle domain and a comprehensive 3-D continuum model to a single cell domain consisting of current collectors, porous electrodes, and separator. The model is first validated against the experimental voltage evolution data measured at various charge and discharge current densities. In general, the model predictions compare well with the experimental data and further highlight key electrochemical and transport phenomena occurring in LIBs. Besides solid electrode/electrolyte potential profiles, multidimensional contours of species concentration, temperature, and current density are analyzed under several different cell configurations in order to provide valuable insight into charge and discharge characteristics of LIBs. The present multiscale LIB model can be applied to a realistic LIB geometry to search for the optimal design and operating conditions.
Best-Match Electrocatalysts from Homologous NixMy (M=O, S, P) Nanobelt Arrays in Overall Water Splitting
Authors: Zhou Wei , Zheng Jinlong , Guo Lin , Lv Yuzhen
Published: February 2020

Homologous NiO, Ni3S2, and Ni2P nanobelt arrays grown on Ni foam were obtained by thermolysis, sulfuration and phosphorization of the same Ni(SO4)0.3OH1.4 belt-like precursors, respectively. Due to their 2D belt morphology and enhanced charge transport capability, they were used as efficient and stable non-noble metal electrocatalysts for water splitting. The influences of lengths and components of the catalysts on the catalytic performance were investigated. The NiO@Ni foam with reaction time of 6 hrs (NiO@NF-6) sample exhibits the overpotential of 0.42 V at 10 mA cm-2 in 1 mol L-1 KOH aqueous solution for oxygen evolution reaction (OER), lower than that of other prepared samples. The Ni2P@Ni foam with reaction time of 6 hrs (Ni2P@NF-6) sample displays the smallest overpotential of -99 mV at 10 mA cm-2 in 1 mol L-1 KOH aqueous solution for hydrogen evolution reaction (HER) of all the prepared samples. When the prepared arrays were deposited on the anode and cathode in a two-electrode setup for overall water splitting, the couple of NiO@NF-6/Ni2P@NF-6 needed only 1.67 V to afford the water splitting current of 10 mA cm-2 and the current density could maintain 95 % for 30 hrs in the long-term test carried out at 1.70 V in 1 mol L-1 KOH aqueous solution. It could be ascribed to the efficient charge transport between the belts and the conducting substrates, the accelerated surface reaction as their considerable specific surface area, and the promoted releasing of gas bubbles from the belt surfaces.