bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Stable Completely Non-Vacuum Process Multi-Porous-Electrodes-Layered Perovskite Solar Cell
Authors: Tsuji Ryuki , Bogachuk Dmitry , Luo Bin , Martineau David , Kobayashi Eiji , Funayama Ryoto , Mastroianni Simone , Hinsch Andreas , Itou Seigo
Published: December 2020

Perovskite solar cells (PSCs) have achieved a photoelectric conversion efficiency of 25 % and can be manufactured only by printing and coating processes, so it expected to be commercialized. However, the organic materials used for PSCs are very unstable to water and oxygen, so long-term durability needs to be improved. Therefore, we focused on a PSCs having a three-layer structure of an electron transport layer (mesoporous TiO2), a spacer layer (mesoporous ZrO2), and a hole transport layer/electrode (Graphite). The scaffold layer of this carbon-based PCSs is manufactured by only printing, and the perovskite precursor solution is drop-cast from graphite layer and infiltration into the scaffold layer to complete the device. This PCSs can perform all of the fabrication processes under non-vacuum conditions. In addition, the thick graphite layer protects the power generation layer from the surrounding air and moisture, and has high long-term stability. In this study, in order to further improve durability and performance, PCSs were fabricated using a perovskite precursor solution using only inorganic materials under completely non-vacuum.

The conductive layer of the FTO glass was removed by etching and separated, and a compact TiO2 blocking layer was formed by spray pyrolysis deposition on the FTO glass. Then, TiO2 paste and ZrO2 paste were deposited by screen printing and sintering at 500 °C. Similarly, graphite paste was printed and sintering at 400 °C. Finally, a perovskite solution was instilled from the graphite layer, the solvent was removed by drying, and the perovskite was crystallized to complete the device. The PSCs was optimized by changing the composition of the paste used for each layer, the layer thickness, and the infiltration method of the perovskite precursor solution. Various material analyzes and solar cell performance evaluations were performed.

The thickness of each layer was controlled by changing the composition of the paste used for each layer and the ratio of the material to the solvent. It was found that the photoelectric conversion efficiency was highest when the TiO2 layer was around 500 nm and the ZrO2 layer was 1.5~2 μm. Also, by improving the infiltration of the precursor solution, the photoelectric conversion efficiency was greatly increased. The graphite paste used to form the graphite layer was made using several types of graphite, and we found the most suitable one for this solar cell.

Figure 1
Seebeck Properties of Sr8Ti7S21
Authors: Kamimizutaru Koki , Nagaoka Akira , Yoshino Kenji
Published: December 2020

Depletion of natural resources and increasing global warming urge the researchers to develop new methods for energy harvesting. The global demand of alternative clean energy is becoming more and more drastic. The conversion of heat into useful electrical energy is an environmentally friendly and straight forward approach to solve the power problems. Thermoelectric materials have been considered to relieve the energy crisis based on the reversible heat and electricity conversion.

We have focused on a new chalcogenide thermoelectric material Sr8Ti7S21 which low lattice thermal conductivity is expected because of a large unit cell (a = 11.5 Å, c = 47.7 Å). However, there are few reports on fundamental and thermoelectric properties. Here, we report growth of Sr8Ti7S21 crystal by solid-state reaction and characterization of its thermoelectric properties. Sr8Ti7S21 polycrystalline sample can be obtained from growth temperature of 900 ºC. The conduction type shows n-type, and Seebeck coefficient of 234 μV/K at 323 K. These results make Sr8Ti7S21 a promising new thermoelectric candidate.
Study on ITO Fresnel Pattern Liquid Crystal Lens
Authors: Woo Jae Geun , Kang In Hye , Kim Seo Gwon , Kang Seok Jun , Bae Byung Seong
Published: December 2020

Everyone is getting old and the presbyopia arise. Conventional presbyopia correction lenses include convex lenses and progressive lenses, each of which has advantages and disadvantages. The convex lens is a short focal length lens, which has the advantage of being able to see immediately when looking at the close, but has the disadvantage that the lens is thick, heavy, and the glasses have to be removed when looking at the distance. Progressive Lens is a multifocal lens that can focus from near to far. It is relatively thin compared to convex lenses, but requires an adaptation period of about 1 to 2 months. To solve this problem, we developed light, thin, and variable refractive index ITO Fresnel pattern lenses using liquid crystals.[1] ITO Fresnel patterns were formed by photo lithography, and the voltages were applied differently for each pattern to drive the liquid crystals, and the focal length was changed as the applied voltage changed. The diopter (D) of the lens has changed over 9V, and showed the maximum diopter of 1 at 13V.

[1] Li, Guoqiang, et al. "Switchable electro-optic diffractive lens with high efficiency for ophthalmic applications." Proceedings of the National Academy of Sciences 103 (16), pp.6100-6104 (2006)
Development of Fast Moving Ball Actuator Mode for Displays
Authors: Lee JongMo , Han Seungoh , Bae Byung Seong , Yoon HoWon , Hong MunPyo
Published: December 2020

Fast moving ball is a moving ball which control the reflected light according to the applied voltages. A tiny ball moves under the applied bias and controlled by designed electrodes. We clarified underlying physics and thereby developed threshold voltage model of a fast-moving ball actuator (FMBA) for reflective electronic display. The proposed threshold voltage model starts from considering all the related forces of Coulomb force, dielectrophoretic (DEP) force, frictional force, and adhesion caused by Van der Waals force, where frictional force consists of vertical Coulomb and DEP forces, buoyancy, and gravity. However, there are many problems for successful commercialization and it is still under research. To put a metal ball in each pixel is difficult and takes long time. To solve them, we used the electroplating conjunction with sacrificial layer. During the formation of the electrodes, the moving ball was formed by electroplating and analyzed the moving of the ball.

Figure 1
Enhanced Photocatalytic H2 Evolution over P-Doped g-C3N4 with Aromatic Rings Composites
Authors: Kobayashi Yuya , Katsumata Hideyuki , Tateishi Ikki , Furukawa Mai , Kaneco Satoshi
Published: December 2020

Introduction

Photocatalytic water splitting is a promising strategy to convert solar energy into chemical energy [1]. In recent years, graphitic carbon nitride (g-CN) has attracted attention due to its desirable properties, including nontoxicity, low cost, thermal stability and visible-light activity [2]. However, the photocatalytic activity of g-CN is limited by the high recombination rate of photoinduced electron-hole pairs [3,4]. In this study, phosphorus doped g-CN with aromatic rings (A/P-CN) composites were prepared. Those composites were evaluated by the photocatalytic hydrogen production under visible light (λ ≥ 420 nm) and characterized by some instrumental analysis.

Results and Discussion

In summary, A/P-CN composite photocatalysts with enhanced photocatalytic H2 evolution performance were successfully synthesized by the calcination of the mixture of urea, 1,3,5-hydroxy benzene and Cl6N3P3. The sample with optimal loading amounts of aromatic rings and phosphorus showed the highest H2 production rate of 550 μmol h-1 g-1, which was about 4.5 times higher than that of pristine g-CN (120 μmol h-1 g-1) (Figure 1). Thus, aromatic rings and phosphorus doped composites push the g-C3N4-based materials forward as the promising visible-light-active photocatalysts with high efficiency in the energy applications.

References

[1] S. Chen, T. Takata, K. Domen, Nat. Rev. Mater.
2017, 2, 17050.

[2] Y. Wang, X. Wang and M. Antonietti, Angew. Chem., Int. Ed.
2012, 51, 68.

[3] G. Liu, P. Niu, C. Sun, S. C. Smith, Z. Chen, G. Lu and H. Cheng, J. Am. Chem. Soc.
2010, 132, 11642.

[4] L. S. Dake, J. Vac. Sci. Technol. A
1989, 7, 1634.

Figure 1
Electrochemical Decolorizaton of Dye in Solution with Modified Ti/α-PbO2/β-PbO2 Mesh Electrode
Authors: Yanagi Genta , Furukawa Mai , Tateishi Ikki , Katsumata Hideyuki , Kaneco Satoshi
Published: December 2020

The synthetic dyes with high stable aromatic structures severely impair watery environments, due to their low biodegradability and deep color-staining. Furthermore, dye pollution would inhibit aquatic plants’ photosynthsis process, decrease the concentration of dissolved oxygen, and contain substances that are toxic to the human body.

The electrochemical oxidation is an attractive advanced wastewater oxidation process, which has been applied in toxic or refractory wastewater treatment, owing to its simplicity, easy operation, environmental compatibility, mild condition and high efficiency. Their degradation performance depends strongly on the selected anode materials. Thus, it is necessary to develop excellent anode materials with high stability and electrocatalytic activity.

Recently, various anode materials have been fabricated and studied. PbO2 electrodes could be regarded as important metal oxide anodes for pollutant remediation, because of their high chemical stability, easy preparation, high oxygen evolution overpotential, good conductivity, high catalytic activity, cheap and available. However, PbO2 film can peel off easily for its relatively large internal stress. The phenomena cause the leakage of Pb ions and releasing into the solution. Therefore, the improvements of stability and electrocatalytic performance for PbO2 electrodes are significant for the application. Recently, many studies have been investigated for the enhancement of electrode performance, such as the modification of substrate, the introduction of interlayers and the doping of metal ions or particles [1-3].

In the previous study, the electrochemical decolorizaton of Methylene blue in solution with Ti/α-PbO2/β-PbO2 Sheet electrode has been investigate. In the present work, Ti/α-PbO2/β-PbO2 Mesh electrode was modifeid by the doping of metal, and have been applied into the electrochemical remediation of Methylene blue in the solution.

References

[1] Y. Yao, B. Ren, Y. Yang, C. Huang, M. Li., J. Hazard. Mater. 2019, 361, 141.

[2] Y. Xia, Q. Dai., J. Hazard. Mater. 2018, 205, 215.

[3] X. Wang, Q. Wu, H. Ma, C. Ma, Z. Yu, Y. Fu, X. Dong. J. Sol. Energy Mater. Sol. Cells, 2019, 191, 381.

Figure 1
Monitoring of Parkinson’s Disease Based on Electrochemical α-Synuclein Sensors and Its Application to Point-of-Care Devices
Authors: Kim Soochan , Cho Misuk , Lee Youngkwan
Published: December 2020

α-Synuclein (α-Syn) is considered to be reliable biomarkers for the diagnosis of Parkinson's disease (PD). We demonstrate a facile and ultra-sensitive electrochemical biosensor for the selective detection of α-Syn oligomer (αSO) using an electrically conductive poly(pyrrole-2-carboxylic acid) (PPy-COOH) and aptamer receptor, without additional agents. The developed biosensor exhibits extremely low detection limit of 10−3 fM with high sensitivity which is desirable for the early diagnosis of PD. Furthermore, the proposed sensor is advanced to a point-of-care (PoC) platforms based on portable smartphone device and the sensing performance of αSO via the developed PoC platform displays remarkable performance like as plug-in potentiostat based sensor.
(Invited) Printed Built-in Power Sources with Dimensional Conformability
Authors: Lee Sang-Young
Published: December 2020

The ongoing surge in demand for flexible/wearable electronics, self-powered systems, soft robotics, and Internet of Things (IoT) has inspired the relentless pursuit of form factor-free, high-performance power sources that can be monolithically and seamlessly integrated with various electronics. To reach this challenging goal, a new class of advanced power sources with various form factors that are different from existing commercial ones are needed. From the viewpoint of power source design and architecture, traditional cell materials and fabrication have resulted in power sources that feature a lack of variety in form factors and flexibility. In specific, most of the current power sources are manufactured by winding or stacking of slurry-casted electrode sheets and separator membranes, followed by the injection of liquid electrolytes inside a fixed form of canisters or pouch packaging substances; these methods impose stringent restrictions on the unitization of power sources with electronic devices. Printed power sources have recently garnered considerable attention as a fresh and game-changing approach due to their design diversity, shape/performance compatibility with electronic devices, and scalable/low-cost processability. Printed power sources based on high-fidelity printing techniques and rationally designed material chemistry are fabricated directly on complex-shaped objects, thereby enabling monolithic integration and electrochemical coupling with target devices that lie far beyond those achievable with conventional power source technologies.

Here, this talk introduces form factor-free, printed built-in power sources, with particular attention to their dimensional conformability and performance compatibility with newly emerging complex-structured electronic devices. A key-enabling technology for the printed power sources is the design of battery inks (specifically, electrode and electrolyte inks), with a focus on their rheology and electrochemistry. Our research interests are directed to discussing effects of the battery inks on printing processability, microstructure (focusing on bicontinuous ion/electron transport channels) and electrochemical performance of the resultant printed power sources. We envision that the printed power sources open a new avenue towards form factor-free/monolithic integrated power sources with object-tailored design versatility and dimensional conformability.

References

[1] Kwon-Hyoung Lee, David B. Ahn, Jung-Hui Kim, Ju-Won Lee, Sang-Young Lee*,
Matter
, 2020, 345.

[2] Kwon-Hyoung Lee, Seong-Sun Lee, David B. Ahn, Jaehyun Lee, Doyouong Byun, Sang-Young Lee*,
Sci. Adv.
, 2020, eaaz1692.

[3] Jihun Park, David B. Ahn, Joohee Kim, Eunkyung Cha, Byeong-Soo Bae, Sang-Young Lee*, Jang-Ung Park*,
Sci. Adv.
, 2019, eaay0764.

[4] Keun-Ho Choi, David B. Ahn and Sang-Young Lee*,
ACS Energy Lett.

2018, 3, 220.

[5] Keun-Ho Choi, JongTae Yoo, Chang Kee Lee and Sang-Young Lee*,
Energy & Environ. Sci.

2016, 9, 2812.

Figure 1
(Invited) Photoluminescent ZnO Thin Films By Photochemical Gel Conversion Under VUV Irradiation
Authors: Sun Lina , Uda Kyota , Yoshida Tsukasa , Suzuri Yoshiyuki
Published: December 2020

Zinc oxide (ZnO), as a wide band gap (3.37 eV) semiconductor, are useful materials for wide range of applications in thin-film transistor (TFT), photovoltaics, photocatalysts, sensors, and so on. Large exciton binding energy (60 meV) at room temperature (RT) makes ZnO a promising luminescent material especially in optoelectronic devices such as UV lasers and light emitting diodes (LED). Among them, ZnO nanocrystals (quantum dots) has attracted increasing attention because their optical properties can be tuned by varying the crystal size. However, its nanoscale crystallites tend to aggregate to undergo Ostwald ripening due to their high surface energy. To stabilize them, surface modification are usually necessary. At the same time, the whole processes for nanocrystal synthesis and film fabrication become complicated.

Here, we report a simple novel photochemical gel conversion approach for one-step preparation of ZnO thin films with an average nanocrystals in about 2-3 nm size (inset in Fig. 1a), by employing vacuum ultraviolet (VUV) light irradiation in dry N2. Systematic characterization is performed to understand the surface chemistry and the optical properties of ZnO nanocrystals. Thus obtained ZnO films show unique absorption peak at 294 nm (4.2 eV) (Fig. 1a) and strong tunable photoluminescence in the range of 386-496 nm when expose to UV light, from violet, blue to bluish-green upon increasing time of VUV irradiation (Fig. 1b). Clearly blue-shifted absorption peaks of the VUV treated samples are indicative of quantum-confinement effect, as contrasted to the broad character of the annealed film, which originates from band structure of bulky ZnO. The extension of VUV time only results in increase of absorbance, with no change of the peak wavelength, indicating population increase but no crystal growth by Ostwald ripening during the VUV irradiation. Therefore, the color change of the emitted light should be associated with the change of defect state distribution, rather than the size effect. However, such photoluminescence from defects was fairly strong to be clearly recognized by naked eyes, so that the university logo could be patterned by photomasking VUV to be seen under black light was demonstrated (inset in Fig. 1b).

Figure 1
(Invited) Texture Control of 3D Printing: Effect of Internal Structure of 3D Printed Foods on their Fracture Process in Compression
Authors: Suzuki Shunsuke , Ogawa Jun , Watanabe Yosuke , Shiblee MD Nahin Islam , Khosla Ajit , Kawakami Masaru , Nango Jun , Furukawa Hidemitsu
Published: December 2020

3D food printing is a method of making a novel three-dimensional processed food based on digital data by applying additive manufacturing technology to food materials mixed with bean jam, dough, and gelling agent. The use of 3D food printer is a device that can make a food with complicated shape and internal structure that is difficult to cook by hand. Since internal structures of food are correlated to their texture, the 3D food printing has recently attracted attention as a method to produce food with a shape and texture suited to individual preferences and needs. The goal of this study is to develop food materials that is printable by a 3D food printer and to find food products that use these materials, as well as to clarify how food texture is changed by its internal structure. For verifying the correlation between the internal structure of food and texture, our food printing uses a screw-based 3D stacking system. With this method, it is easy to add food materials during modeling. It is possible to create a three-dimensional food product with an improved texture reproduction rate of the target model by avoiding dripping from the nozzle in principle. This study evaluates the correlation with texture by modeling baked confectionery with a geometrical internal structure and quantitatively measuring the compression fracture process.

Figure 1
(Invited) Soft-Matter Robot That Communicates Humans By Contacting
Authors: Kameyama Takaaki , Ogawa Jun , Watanabe Yosuke , Shiblee MD Nahin Islam , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu
Published: December 2020

The research of soft robots composed of soft materials, named "Soft-matter Robotics", has been drawn attention because it is useful as a technology with high interpersonal affinity. The soft-matter robots have a potential advantage in non-destructive behaviors such as picking up an egg without breaking it. On the other hand, IoT / AI technologies such as smart speakers have become popular in the past several years from the viewpoint of software functions of robots. Robots equipped with communication functions based on IoT technology are also gradually permeating our lives.

In the situation where the robot directly touches the human, the soft-matter robot fused with the IoT technology will have the flexibility of the body and the IoT sensor module, so that it is possible to achieve the advanced interaction without damaging the human. However, the softness of the soft-matter robot depends on its material characteristics. It is necessary for realizing the advanced communication to clarify the property of the sensing data of physical contact with human that the installed IoT module can acquire from the material.

This study verifies whether the touching method such as poking, stroking and so on of a three-dimensional object of additive type silicone rubber can be classified through a vibration sensor. Then, we develope a robot that communicates with humans by feeding back the sensed data with light and vibration.

Figure 1
(Invited) Formation of Liposomes Containing Pre-Gel Solution and 3D-Printing Applications by Droplet-Shooting Method
Authors: Adachi Kanako , Yoshida Kazunari , Makino Masato , Morita Masamune , Watanabe Yosuke , Shiblee MD Nahin Islam , Ogawa Jun , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu
Published: December 2020

A liposome is a spherical particle formed by a surfactant bilayer. This particle uses in drug delivery systems, in cosmetics as a model of cell membranes and it often studies in biology and medical science. Furthermore, new materials including polymer-reinforced liposomes have the potential to be applied as mechanical materials for soft equipment in soft robots from the viewpoint of texture expression. On the other hand, there is a problem that the liposome is not suitable as a mechanical material because the liposome is soft and fragile.This study uses liposomes with gel materials such as gelatin and shape memory gel (SMG) to enhance their resistance to mechanical stress. We show the encapsulation procedure gelatin and pre-gel solutions for SMG in liposomes by using the Droplet-Shooting method. This procedure allows the encapsulation of liposomes by gel. Some droplets are shot from the tip of capillary, through the oil-water interface and become liposomes. First, we incorporate gelatin into liposomes, however the gelatin solution has higher viscosity than water. Therefore, this process should be confirmed the effect of the viscosity of gelatin on liposomes generated by the Droplet-Shooting Method. In the case of SMG, we can observe the effect of the UV irradiation on the liposome containing the pre-gel solutions because the irradiation of UV makes the lipid membrane unstable and then breaks liposomes. This study discuss stable formation of polymer-reinforced liposome. We believe that our procedure will contribute to the making novelty materials.

Figure 1
(Invited) A Novel Self-Localization Method for USV Based on GPS and Visual-Map
Authors: Zou Xiong , Xiao Changshi , Zhan Wenqiang , Chen Qianqian
Published: December 2020

With the vigorous development of computer technology, information technology and intelligent transportation, their combination in the maritime field is becoming more and more extensive. At present, unmanned surface vehicle (USV) has been widely applied in the water transportation environment, especially for dangerous and time-consuming tasks. However, the intellectualization of USV is still far from actually being “unmanned”. Among them, USV uses its own sensors to perceive the surrounding environment and obtain high-precision position estimation is a prerequisite for its intelligence. In response to the demand, a novel two-step approach for USV self-localization is proposed in this paper. In the first step, the coarse-to-fine strategy is used to obtain the nearest node. Firstly, coarse image node is got by matching the current GPS information and the DGPS information of the visual-map. Then, the fine image node is obtained by the multi-vector fusion algorithm. In the second step, the pose of the current image is gained with respect to the nearest node by the epipolar geometry constraint, so as to achieve high-precision self-localization for USV. This method only needs an ordinary camera and GPS module in positioning, which can reduce the cost of high-precision positioning to the greatest extent. Pool experiments show that this method can achieve centimeter-level positioning accuracy.
Photoinduced Energy and Electron Transfer in Nanocarbon-Based Donor-Acceptor Systems
Authors: Imahori Hiroshi
Published: December 2020

Nanocarbons have attracted tremendous attention, as their extended π-conjugation offers intriguing characteristics in optical and electronic properties. These properties suggest their potential utility as basic components in various electronic devices including light-emitting diodes, solar cells, and field-effect transistors.

In this talk, I will give an overview of our recent works focusing on photoinduced electron and energy transfer in nanocarbon-based systems. For instance, excitation of a porphyrin–hexabenzocoronene linked system resulted in selective energy transfer (EnT) from the first singlet excited state (S1) of the hexabenzocoronene to the porphyrin. In contrast, reverse exclusive EnT took place from the first and second singlet excited states (S1 and S2) of the porphyrin to the π-extended hexabenzocoronene in the porphyrin–π-extended hexabenzocoronene linked system. Specifically, ultrafast efficient EnTs from both the S2 and S1 states of the porphyrin to the π-extended hexabenzocoronene are similar to the corresponding ultrafast EnTs from the S2 and S1 states of carotenoids to chlorophylls in natural photosynthesis. Such characteristic photophysical properties will be informative for the elaborated design of nanocarbon-based materials for optoelectronics and solar energy conversion.

[1] T. Umeyama, T. Hanaoka, H. Yamada, Y. Namura, S. Mizuno, T. Ohara, J. Baek, J. Park, Y. Takano, K. Stranius, N. V. Tkachenko, H. Imahori, Chem. Sci., 10, 6642 (2019).

[2] X. Liu, M. Kozlowska,T. Okkali, D. Wagner,T. Higashino, G. Brenner-Weiß, S. Marschner, Z. Fu, Q. Zhang, H. Imahori, S. Bräse, W. Wenzel,C. Wöll, L. Heinke, Angew. Chem. Int. Ed., 58, 9590 (2019).

[3] T. Umeyama, K. Igarashi, D. Sasada, Y. Tamai, K. Ishida, T. Koganezawa, S. Ohtani, K. Tanaka, H. Ohkita, H. Imahori, Chem. Sci., in press.
Contribution of Different Exfoliation Mechanisms in the Bipolar Electrochemical Fabrication of Graphene
Authors: Khakpour Iman , Rabiei Baboukani Amin , Allagui Anis , Wang Chunlei
Published: December 2020

Since the discovery of graphene, two-dimensional (2D) materials have attracted increasing interest due to their extraordinary properties such as high thermal conductivity, high specific surface area, and broad electrochemical window. In general, different techniques have been employed to fabricate these materials, including chemical vapor deposition, mechanical, chemical, and electrochemical exfoliation. Bipolar electrochemistry (BPE) is one of the newest methods which has been used for the fabrication of 2D materials. In our previous study, a modified BPE concept was developed for simultaneous exfoliating and deposition of both reduced graphene oxide (rGO) and graphene oxide (GO) layers on conductive objects. Although the characteristics of the produced materials have been studied and reported, there are still remaining questions that need more investigations to be answered. The main focus of this study is investigating the active exfoliation mechanisms in the BPE process and finding out the dominant exfoliation reactions (either cathodic or anodic exfoliation).

For this purpose, a novel and unique modified bipolar system has been developed, which could retard either anodic or cathodic exfoliation of graphite by replacing the relevant sites of the bipolar electrode with a platinum wire. This helped to have a better understanding of the source of produced rGO and GO. The morphology and functional groups of deposited materials on both negative and positive feeding electrodes were investigated when the graphite was polarized to either positive or negative potentials. The results proved that both anodic and cathodic exfoliation mechanisms are active at the same time when using graphite as the bipolar electrode. However, the morphology, functional groups, level of oxidation, the bipolar current, and deposition rate vary according to the exfoliation mechanism. The developed modified BPE technique and materials characterizations will be discussed in detail at the conference.

Keywords: Electrochemical exfoliation, bipolar electrochemistry, 2D materials, graphene fabrication
Spacers to Improve Performance and Porosity of Graphene Based Polymer Electrolyte Fuel Cells
Authors: Suter Theo , Clancy Adam , Rubio Carrero Noelia , Heitzmann Marie , Guetaz Laure , Shaffer Milo , Howard Christopher A. , McMillan Paul F. , Brett Dan
Published: December 2020

Fuel Cell are energy generation alternatives to the traditional fossil fuel dependant transport and energy sectors. A typical polymer electrolyte membrane fuel cell (PEMFC) generates power from the electrochemical reaction between hydrogen and oxygen which forms water. While PEMFC have become increasingly commercialised in the last decade there needs to be a significant cost reduction before the technology sees a much wider uptake. One of the key methods to reduce costs of PEMFCs is to reduce the platinum loading. Significant research has investigated non-platinum groups metals or ultra-low Pt loadings, however these have other technological barriers that need to be surpassed before they are widely commercialised. Increasing the lifetimes of fuel cell stacks is one other method to make costs competitive with traditional power generation. Carbon support corrosion is one of the key decomposition pathways of a fuel cell, this entails degradation and loss of the carbon support with use leading to loss of Pt catalyst, ionomer and reduction of proton and electron conduction.

Highly graphitised carbon supports have been reported to be have superior carbon corrosion resistance compared to commercial carbon black. This has often been attributed to the sp2 carbon framework being more resilient to oxidation. Graphene and few layer graphite (FLG) are composed of sheets of sp2 carbon, high surface areas graphene has been developed. However when deposited as a catalyst layer the sheets restack during drying, forming a dense, low porosity electrode with low current densities. The potential carbon corrosion benefits of graphene cannot be observed reliably when operated at low current densities, it is therefore imperative to develop methods to control the morphology and layering of graphene based electrodes to mitigate this performance loss. In this work we report a series of method that utilises sacrificial additives and spacers to scalably control the morphology of graphene based electrodes. We show significant increases in current density, porosity and Pt utilisation via this method. In addition we discuss the effect of graphene size, source and treatment on performance of PEMFC cathodes.

Figure 1
Silicon Phthalocyanine Modified Multi-Walled Carbon Nanotubes As a Novel Metal-Free Catalyst for the Oxygen Electroreduction
Authors: Kruusenberg Ivar , Kaare Kaitlin , Tsujimoto Masahiko
Published: December 2020

Finding an alternative catalysts for the oxygen reduction reaction (ORR) has been a key issue in modern electrocatalysis. Traditional platinum-based catalysts are not viable in the long term and thus much effort has been focused on non-precious metal catalysts. Heteroatom doped and metal-heteroatom co-doped carbon materials have emerged as the main candidate for replacing the platinum-based catalysts. Different MN4 macrocycles, such as metal phthalocyanines and porphyrins, have been studied as promising materials to prepare electrocatalysts for ORR in alkaline media [1]. While the development of non-precious metal and non-metal carbon catalysts has gained a lot of attention recently, non-metal phthalocyanines are a less studied topic [2].

In this work a novel catalyst material including multi-walled carbon nanotubes (MWCNT) and silicon phthalocyanine dichloride (SiPcCl2) was synthesised and the electrochemical activity towards the oxygen reduction reaction (ORR) in alkaline media was studied. Different ratios of phthalocyanine-to-nanotubes were pyrolysed at 800 °C. After optimising the ratio of phthalocyanine-to-nanotubes, the pyrolysis process was also carried out at different temperatures, but the results showed that the best temperature for pyrolysis is still 800 °C. ORR activity on SiPc/MWCNT catalyst was studied in 0.1 M KOH by employing rotating disc electrode method. Physical characterisation was carried out with X-ray photoelectron spectroscopy and transmission electron microscopy. The results showed successful incorporation of silicon and nitrogen into the carbon framework. We show that doping MWCNTs with a non-metal phthalocyanine creates a highly active ORR catalyst rivaling the activity of metal-based catalysts in alkaline conditions. This work clearly demonstrates that non-metal macrocyclic compound modified carbons, similar to the the SiPc/MWCNT can be used as alternative cathode catalysts for the metal-air batteries and alkaline membrane fuel cells.

[1] Y. Liu, X. Yue, K. Li, J. Qiao, D.P. Wilkinson, J. Zhang, PEM fuel cell electrocatalysts based on transition metal macrocyclic compounds, Coord Chem Rev. 315 (2016) 153-177.

[2] K.-K. Türk, K. Kaare, I. Kruusenberg, M. Merisalu, U. Joost, L. Matisen, V. Sammelselg, J.H. Zagal, K. Tammeveski, Oxygen electroreduction on zinc and dilithium phthalocyanine modified multiwalled carbon nanotubes in alkaline media, J. Electrochem. Soc. 164 (2017) H338-H344.
Hole Defect-Rich Nitrogen Doped Carbon Nanotubes for Efficient Oxygen Reduction and Evolution Reactions in Rechargeable Zinc-Air Battery
Authors: Choi Eun Yeop , Kim Dong Eun , Kim C. K.
Published: December 2020

Environmental concerns arising from the use of conventional fuel sources have driven the demand and development of eco-friendly vehicles. However, determining the right battery to use in them remains challenging. As an alternative to Li-ion batteries, Zn–air batteries are promising, but limited by their charge-discharge cycling efficiency and safety issues. Hence, in this study, nitrogen-doped holey carbon nanotubes (N-HCNTs) were fabricated for use as a cathode material of Zn–air batteries. Holes were formed in the CNT by reacting it with hydrogen peroxide, following which the oxidized CNT was pyrolyzed with urea to form N-HCNT. Nitrogen-doped CNTs (N-CNTs) were also produced by pyrolyzing acid-treated CNTs with urea to compare their electrocatalytic activities in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with those of N-HCNT. N-HCNT exhibited much better electrocatalytic activity toward the ORR and OER than N-CNT. The charge transfer resistance and density functional theory calculation indicated that the high electrocatalytic activity of the N-HCNT is due to its high electrical conductivity. The electrocatalytic activity of N-HCNT was compared with those of Pt/C and IrO2; N-HCNT exhibited excellent bifunctional electrocatalytic activity in both, the ORR and OER, while Pt/C and IrO2 exhibited excellent electrocatalytic activity only in the ORR and OER, respectively. Further, the maximum power density of a Zn–air rechargeable battery using the N-HCNT electrode was 17.6% higher than that of a battery using a mixture of Pt/C and IrO2 (1:1) as the electrode. Moreover, after 500 cycles, the change in the charge-discharge voltage gap of the battery using the N-HCNT electrode (18.3%) was much smaller than that of the battery using the mixture of Pt/C and IrO2 (118.1%). The excellent electrocatalytic activity and cycle life of the N-HCNT electrode in Zn–air battery demonstrate its promise in the development of future energy devices.
High Temperature Oxidation Modeling
Authors: Wen You-Hai
Published: December 2020

One of the most demanding properties for reliable high temperature structural materials is oxidation resistance. The transition from internal to external oxidation is often a basis for alloy design to slow down the oxidation process. While lots of experimental efforts have been devoted to investigating the transition, there is still a significant gap in understanding the relevant mechanisms. This can be partly attributed to a lack of physics-based modeling capabilities due to the difficulty in constructing a coherent and consistent thermodynamic framework for oxidation modeling in multi-component alloy systems and the complexity of the interplay among the various governing factors for oxidation – a rich topic for Integrated Computational Materials Engineering. To bridge this gap, one of the tasks in the on-going XMAT project sponsored by US-DOE that involves 7 National Laboratories is to develop a phase-field modeling capability for an alloy system where the oxidation transition can be simulated. In this presentation, we will describe a phase-field model for a ternary prototype system where competition of a faster-growing oxide and a thermodynamically-more-stable oxide can be considered. The model captures the oxidation reactions at the surface and in the bulk, as well as the interdiffusion of oxygen and other elements. The application of this model to investigate internal to external oxidation transition will be discussed.
Alloy Plating for Improved Molten Salt Reactor Performance
Authors: Hall Timothy , Ahmadi Kamyar , Radhakrishnan Rajeswaran , Snyder Stephen , Raiman Stephen S
Published: December 2020

The use of molten fluoride salts as a primary coolant within next generation nuclear reactors has the potential to improve efficiency and nuclear reactor safety by operating at low pressures and high temperatures without boiling. However, these coolants will require the development of new corrosion resistant material systems that will have to meet or supersede existing standard codes for these systems. Therefore, state of the art reactors require validation and testing of new material systems that can produce robust component structures and enable them to withstand these corrosive environments. Furthermore, any next generation process to apply protective coatings must allow for a conformal, thick, dense, and bonded materials to be formed onto any low cost ASME material (like 316H SS) that comprises the structure of heat exchanger and containment vessel components.

Within this context, Faraday Technology Inc. is working on developing low cost and high value corrosion-resistant alloy coatings for next generation molten salt reactors with the goal of increasing their functional lifetime, while reducing the component cost. The manufacturing process involves electrodeposition of functionally graded NiMo alloys onto ASME certified substrates and subsequent high temperature corrosion evaluation in molten fluoride salt electrolytes. A wide array of electrolytes and processing parameters were evaluated in order to understand these effects on the deposit composition, structure, and corrosion resistance properties towards the goal of developing an ideal alloy coating. Specifically, we demonstrated the potential to apply graded NiMo coating to the 316H SS surface (Figure 1) and found that a coating composition of ~25% Mo has the potential to improve the components lifetime.

Figure 1
(Invited) Benefits of Zr Addition on Hot Corrosion and Isothermal Oxidation Resistance of Single-Phase (Ni,Pt) Al Coatings
Authors: Jiang Chengyang , Bao Zebin , Zhu Shenglong , Wang Fuhui
Published: December 2020

A Zr-doped single-phase (Ni,Pt)Al coating was prepared on a Ni-based single crystal superalloy through electroplating Pt-Zr composite layer and subsequent gaseous aluminisation treatments. Hot corrosion tests of (Ni,Pt)Al and Zr-doped (Ni,Pt)Al coatings in Na2SO4/NaCl (75:25, wt./wt.) were conducted at 850 ºC in static air. The results indicated that the Zr-doped coating showed superior hot corrosion resistance to conventional (Ni,Pt)Al coatings, in which the enhanced performance is mainly attributed to the advantageous effects of Zr that interacts with S and Cl. The mechanism and role of Zr played in the corrosion test are discussed. Moreover, isothermal and cyclic oxidation behavior of the Zr-doped (Ni,Pt)Al coating samples were assessed at 1373 K in static air compared with normal (Ni,Pt)Al coatings. The results indicated that Zr-doped (Ni,Pt)Al coating demonstrated lower oxidation rate constant and reduced tendencies of oxide scale spallation as well as surface rumpling, in which the enhanced oxidation performance was mainly attributed to the favoring effects of Zr preferring to segregate at grain boundaries of oxide scale and improving Young’s Modulus of the coating. Besides, the addition of zirconium effectively delayed the oxide phase transformation from θ-Al2O3 to α-Al2O3 in early oxidation stage and the coating degradation from β-NiAl to γ'-Ni3Al in stable oxidation stage.
Genetic Variability, Heritability, and Clustering Pattern Exploration of Bambara Groundnut (Vigna subterranea L. Verdc) Accessions for the Perfection of Yield and Yield‐Related Traits
Authors: Khan Md Mahmudul Hasan , Rafii Mohd Y. , Ramlee Shairul Izan , Jusoh Mashitah , Mamun Al
Published: December 2020

Bambara groundnut (Vigna subterranea L. Verdc.) is considered an emerging crop for the future and known as a crop for the new millennium. The core intention of this research work was to estimate the variation of landraces of Bambara groundnut considering their 14 qualitative and 27 numerical traits, to discover the best genotype fitted in Malaysia. The findings of the ANOVA observed a highly significant variation (p ≤ 0.01) for all the traits evaluated. There was a substantial variation (7.27 to 41.21%) coefficient value, and 14 out of the 27 numerical traits noted coefficient of variation (CV) ≥ 20%. Yield (kg/ha) disclosed positively strong to perfect high significant correlation (r = 0.75 to 1.00; p ≤ 0.001) with traits like fresh pod weight, dry pod weight, and dry seed weight. The topmost PCV and GCV values were estimated for biomass dry (41.09%) and fresh (40.53%) weight with high heritability (Hb) and genetic advance (GA) Hb = 95.19%, GA = 80.57% and Hb = 98.52%, GA = 82.86%, respectively. The topmost heritability was recorded for fresh pod weight (99.89%) followed by yield (99.75%) with genetic advance 67.95% and 62.03%, respectively. The traits with Hb ≥ 60% and GA ≥ 20% suggested the least influenced by the environment as well as governed by the additive genes and direct selection for improvement of such traits can be beneficial. To estimate the genetic variability among accessions, the valuation of variance components, coefficients of variation, heritability, and genetic advance were calculated. To authenticate the genetic inequality, an unweighted pair group produced with arithmetic mean (UPGMA) and principal component analysis was executed based on their measurable traits that could be a steadfast method for judging the degree of diversity. Based on the UPGMA cluster analysis, constructed five distinct clusters and 44 accessions from clusters II and IV consider an elite type of genotypes that produce more than one ton yield per hectare land with desirable traits. This study exposed an extensive disparity among the landraces and the evidence on genetic relatives will be imperative in using the existing germplasm for Bambara groundnut varietal improvement. Moreover, this finding will be beneficial for breeders to choose the desirable numerical traits of V. subterranea in their future breeding program.
Sulforaphane Attenuates Isoproterenol‐Induced Myocardial Injury in Mice
Authors: Song Lijuan , Srilakshmi Mudduluri , Wu Yi , Saleem T. S. Mohamed
Published: December 2020

The development of isoproterenol‐ (ISO‐) induced oxidative stress in the myocardium results in myocardial necrosis. Sulforaphane (SFN‐0.4% of sulforaphane from standardized broccoli sprout extract) possesses chemoprotective, antidiabetic, and antibacterial activities and is also active against cardiovascular‐related problems due to its antioxidant properties. This study was designed to investigate the cardioprotective effect of SFN against isoproterenol‐induced myocardial injury in mice. Healthy male Swiss albino mice weighing 20–30 g were used in this study. These mice were randomly divided into five groups (n = 6). All the mice in the experimental groups received isoproterenol (5 mg/kg bw, via i.p.) consecutively for 2 days. The mice were treated with SFN (4 mg/kg bw) and α‐tocopherol (TCF) (10 mg/kg bw) by oral gavage for 1‐7 days as pre‐ and posttreatment for the prophylactic and treatment groups, respectively. On day 10, the following parameters were studied: heart weight to body weight ratio, antioxidant parameters, and cardiac markers; and mitochondrial enzymes were estimated for cardioprotection. Administration of isoproterenol in mice showed an increased level of serum cardiac markers and heart mitochondrial ATPase enzymes. An increased level of myocardial thiobarbituric acid‐reactive substance and decreased levels of endogenous antioxidant enzymes indicated that oxidative stress is induced by isoproterenol in the myocardium. The administration of SFN in mice restored the levels of all biochemical parameters to near‐normal levels. Histopathological studies further confirmed the protective effect of sulforaphane. This study concluded that treatment with SFN boosts the endogenous antioxidant activity and prevents isoproterenol‐induced myocardial injury.
An Integrated Health Condition Detection Method for Rotating Machinery Using Refined Composite Multivariate Multiscale Amplitude-Aware Permutation Entropy
Authors: Zhou Fuming , Liu Wuqiang , Feng Ke , Shen Jinxing , Gong Peiping
Published: December 2020

With a view to realizing the fault diagnosis of rotating machinery effectively, an integrated health condition detection approach for rotating machinery based on refined composite multivariate multiscale amplitude-aware permutation entropy (RCmvMAAPE), max-relevance and min-redundancy (mRmR), and whale optimization algorithm-based kernel extreme learning machine (WOA-KELM) is presented in this paper. The approach contains two crucial parts: health detection and fault recognition. In health detection stage, multivariate amplitude-aware permutation entropy (mvAAPE) is proposed to detect whether there is a fault in rotating machinery. Afterward, if it is detected that there is a fault, RCmvMAAPE is employed to extract the initial fault features that represent the fault states from the multivariate vibration signals. Based on the multivariate expansion and multiscale expansion of amplitude-aware permutation entropy, RCmvMAAPE enjoys the ability to effectively extract state information on multiple scales from multichannel series, thereby overcoming the defect of information loss in traditional methods. Then, mRmR is adopted to screen the sensitive features so as to form sensitive feature vectors, which are input into the WOA-KELM classifier for fault classification. Two typical rotating machinery cases are conducted to prove the effectiveness of the raised approach. The experimental results demonstrate that mvAAPE shows excellent performance in fault detection and can effectively detect the fault of rotating machinery. Meanwhile, the feature extraction method based on RCmvMAAPE and mRmR, as well as the classifier based on WOA-KELM, shows superior performance in feature extraction and fault recognition, respectively. Compared with other fault identification methods, the raised method enjoys better performance and the average fault recognition accuracy of the two typical cases in this paper can all reach above 98%.