bluuebunny/crossref_metadata_2025_split huggingface dataset:
Graphene Chemical Modification
Authors: Hernandez Sandra Catalina , Junkermeier Chad , Dev Pratibha , Lee Woo , Robinson Jeremy , Sheehan Paul , Reinecke Thomas , Walton Scott 
Published: February 2020

Graphene has been a research focus due to its numerous unique properties which have motivated vast interdisciplinary research in the search of materials for next-generation technologies. With its unique atomically thin nature, graphene has enabled a closer look at material surface interactions and highlighted the importance of surface interfaces, defects and adsorbates. Purposeful and native defects have demonstrated to have advantageous or adverse influences on the chemical, electrical, optical, mechanical and even magnetic properties of graphene. On the other hand, control of the localization of defects and their arrangement onto ordered and extended structures has enabled new graphene-based materials with novel properties.
It is clear that fundamental understanding of the modification of graphene relies on the understanding of the chemical functionalization dynamics, kinetic barriers, chemical transitions, and diffusion energies experienced by the added adsorbates with the graphene surface as well as the influence of the substrate on each.
Plasmas provide both ease and versatility by enabling a single tool process on a wide range of background gases. In particular, electron-beam generated plasmas can introduce different functional groups over a large coverage range with atomic layer precision, allowing for global or local surface chemistry modulation with a large range of functional group types. Here in we demonstrate the effect of functional group type and quantity on chemical and structural changes. In particular, the degree of graphene lattice distortion as they originate for -oxygen, -fluorine, -hydrogen and -nitrogen functionalities with increasing surface coverage, demonstrating chemical and structural dependence on functional group types (F, O, H, N) and substrate interactions.
Hierarchical Porous Carbon Scaffolds As a Materials Scaffold for the Attachment of Silicon in Lithium Ion Battery Anodes
Authors: Estevez Luis , Jeong Sookyung , Cao Ruiguo , Zheng Jianming , Li Xiaolin , Xu Wu , Zhang Ji-Guang 
Published: February 2020

Carbon and carbon-based composite materials have long been an important component in electrodes utilized for energy storage applications. Their widespread use can be attributed to their combination of good electrical conductivity, relative chemical inertness and low bulk material density (~2 g/cm3). For lithium ion battery (LIB) anodes, graphite is typically employed, but silicon has been heralded an excellent replacement candidate due to its very high theoretical capacity (~ 4200 mAh/g—a capacity over ten times greater than that of graphite). A principal obstacle for the practical application of a Si anode is the extreme volume changes (> 300%) during the lithiation process which eventually leads to a pulverization of the Si material. This is particularly true for larger Si particles (> 200 nm), which severely compromises the commercialization of Si based LIB anodes.
Herein, we present our recent work utilizing various carbon-silicon composite materials systems as LIB anodes. We will show that by using a hierarchical porous carbon scaffold with tailorable textural properties such as pore size, surface area and pore volume, we are able to provide silicon nanoparticles with an excellent scaffold for attachment. Furthermore, we will reveal how this tailorable carbon structure can be further modified via functionalization pathways for both the carbon and silicon materials. We will demonstrate how these strategies improved various performance parameters for these LIB anodes; specifically in terms of cyclic performance—a characteristic weak point for silicon-based LIB anodes.
Carbon Nanocomposite for Photo-Energy Conversion
Authors: Shen Yanfei 
Published: February 2020

Manipulating molecular interaction and assembly for developing various functional nanostructures with controlled dimensionality, morphology and tailored properties are currently a research focus in molecular science and materials chemistry. Particularly, the self-organization of fullerenes (i.e. C60) to form various functional assemblies has received intense interest since it can provide excellent optoelectronic properties for photo-energy conversion-induced applications such as solar cells and field effect transistors (FET).
A nanocarbon hybrid of SWCNT and alkylated-C60 derivative was constructed as a donor-acceptor pair for photovoltaics and nanodevice investigations. The appropriate affinity of the long aliphatic chains of alkylated-C60 with the SWCNT surface allows solubilization of SWCNT in organic solvents without disturbing their intrinsic electronic structures. Moreover, the supramolecular assembly of alkylated-C60 and SWCNT is expected to show emergent properties such as photo-induced energy/electron transfer between the two components, and water-repellency at surface. Viaa wet process, the nanocarbon assembly-modified transparent electrodes and single-SWCNT-device were fabricated and performed well for photovoltaic studies. In addition, a superhydrophobic surface was facilely fabricated from the same nanocarbon hybrid. The additional surface feature in the assembly provides an extra benefit for their photovoltaic application, i.e., towards the fabrication of water-proof devices.
In addition, the self-organized microparticles of SWCNT and alkylated-C60 can be used as a temperature indicator for the photo-thermal conversion of SWCNT upon near-infrared (NIR) irradiation, where the fullerene microparticles act as a matrix, and SWCNT as an additive. Upon NIR irradiation, the temperature rise can be confirmed via the melt-induced morphological changes of the nanocarbon co-assembly. Since local heating of SWCNT is widely used in biology such as cancer photo-therapies, our results serve as a reminder that NIR irradiation of SWCNT can induce an extreme temperature rise, e.g., 220 ˚C.

References

[1] T. Nakanishi, Chem. Commun., 46, 3425-3436 (2010)
[2] T. Nakanishi, et al., Adv. Mater. 20, 443-446 (2008)
[3] Y. Shen, et al., Chem. Eur. J., 15, 2715-2767 (2009)
[4] Y. Shen, et al., Chem. Sci., 2, 2243-2250 (2011)
[5] Y.Shen, et al., Adv. Optical Mater., 3, 925-930 (2015)
[6] Y. Shen, et al., J. Am. Chem. Soc.
132, 8566-8568 (2010)

Figure 1
Effects of Deposition Temperature on Synthesis of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films on Cemented Carbide Substrate By Coaxial Arc Plasma Deposition
Authors: Egiza Mohamed , Naragino Hiroshi , Tominaga Aki , Murasawa Kouki , Gonda Hidenobu , Sakurai Masatoshi , Yoshitake Tsuyoshi 
Published: February 2020

Synthesis of hard carbon coatings on cutting tools is indispensable for machining the nonferrous materials and carbon fiber composites. Diamond, an allotrope of carbon, is classified at the top of carbon coatings for its unique characteristics, it has the highest known hardness and thus provides superior wear resistance. A diamond crystal consists of carbon atoms tetrahedrally bonded with sp3 hybrid bonds. On the basis of its crystal size, polycrystalline diamond is categorized to microcrystalline, nanocrystalline, and ultrananocrystalline diamond. Ultrananocrystalline diamond/amorphous carbon composite (UNCD/a-C) films, wherein a large number of diamond grains with diameters of less than 10 nm are embedded in an amorphous carbon matrix. A high hardness of UNCD/a-C films is attributed to the refinement of grains in nanoscale and its resultant high content of sp3-bonded carbon.
To provide highly energetic carbon atoms and thus sp3-rich amorphous carbon films, cathodic arc discharge has ever been employed. In addition to the merits of cathodic arc discharge, coaxial arc plasma deposition technique (CAPD) has the following distinctive feature: a coaxial arc plasma gun is equipped with an anodic cylinder that can bunch ions ejected from a cathodic graphite rod located inside the cylinder. Owing to this structure, a supersaturated condition with highly energetic ions can be realized, which is desired for the growth of UNCD crystallites
In this work, the influences of deposition temperature on growth and mechanical properties of the UNCD/a-C films were studied. The films were deposited at different temperatures on cemented carbide (WC-6wt.% Co) plate substrates by using CAPD. The hardness and elastic modulus were investigated by nanoindentation. Structural characterizations of the films have been examined by X-ray diffraction, scanning electron microscopy, hard X-ray photoelectron spectroscopy, and energy-dispersive X-ray. The revealed mechanical and structural properties will be presented.
Simultaneous Interferometry and Microscopy Reveal Unexpected Nickel Corrosion Dynamics in Confined Geometry
Authors: Merola Claudia , Cheng Hsiu-Wei , Kristiansen Kai , Chen Ying-Ju , Israelachvili Jacob , Valtiner Markus 
Published: February 2020

Corrosion of nickel and its alloys in confined areas remains a serious concern for the safety of structural materials. We uniquely combined white light interferometry and microscopy with high spatial and time resolution for a real-time study of the corrosion mechanism of confined nickel surfaces in alkali metal chloride (e.g., NaCl) electrolytes (c = 1 – 100 mM) at pH = 7. A mica surface is used as crevice former in the electrochemical surface forces apparatus to establish 600-1000 µm2 confined dry areas on extended nickel surfaces. NaCl is the wetting medium of the confined zones and the electrolyte layer spreads out along all the surface. The nickel surfaces form interfacial oxides films at the beginning when no electrochemical potential is applied. Subsequent application of an electrochemical potential ramp from -400 mV to +800 mV initiates severe corrosion of the formed crevices. Surprisingly, the corrosion inside the crevices proceeds as preferential and self-catalyzed “pitting” corrosion (inhomogeneous localized dissolution with the formation of pits) within in the confined zone. Moreover, different behavior of the Nickel corrosion is observed depending on the concentration: inside the confined zone at low concentration (<10mM) and outside the crevice at higher chloride concentrations (>10mM). Our data reveal a surprising and detailed view into the initial corrosion mechanism of nickel surfaces in confined zones, and may contribute to a deeper understanding and, ultimately, prevention of localized corrosion of other metallic surfaces. A double-layer theory coupled with diffusion-limited effects provides a plausible explanation for the observed phenomena.
Corrosion Fatigue Behavior of Low-Carbon Structural Steel in NaCl Solution
Authors: Otsuka Misaki , Tada Eiji , Nishikata Atsushi 
Published: February 2020

Corrosion fatigue is one of the environmental degradations of metallic materials and it has become a great concern as the cause of failure of infrastructures such as bridges and offshore structures. Although it is well-known that corrosion can enhance the degradation of fatigue life, the detailed mechanism of corrosion fatigue is still unclear. Therefore, it is needed to clarify the effects of corrosion on corrosion fatigue life and on the behavior of crack initiation and propagation under cyclic deformation. In this study, corrosion fatigue behavior of low-carbon structural steel is investigated by 4-point bending tests in aqueous NaCl.
The material used in this study was low-carbon structral steel (JIS SM490). The chemical composition of the steel is listed in Table 1. The material was heat-treated at 845 OC for 45 min and then quenched in an oil bath. Furthermore, the material was tempered at 550 OC for 60 min and then cooled in a water bath. The mechanical properties of the heat-treated material were evaluated to be 442 MPa of yield stress and 614 MPa of tensile stress. The heat-treated material was machined into a V-notched 4-point bending specimens in the size of 8 mm wide, 100 mm long, and 4 mm thick. The V-shaped notch of 1 mm in depth was introduced at the center of the specimens. The 4-point bending tests were performed in 1 M and 0.1 M NaCl solutions. The applied stress waveform was triangular at the stress ratio of 0.18 and the frequency of 0.167 Hz. The maximum stress applied to the specimens was changed in the range from 500 MPa to 600 MPa.
In this study, fatigue life of the steel was investigated as a function of applied maximum stresses. It was found from the results that fatigue life of the steel was reduced in aqueous NaCl compared with that in air. In addition, the fatigue life in aqueous NaCl was improved by applying a cathodic potential to the steel. These results indicate that anodic dissolution of iron can enhance corrosion fatigue damage of the steel in NaCl environment. In addition, although corrosion fatigue life evaluated in 1 M NaCl was almost the same as that in 0.1 M NaCl, crack initiation was accelerated in 1 M NaCl compared with that in 0.1 M NaCl. This suggests that crack propagation is retarded due to the blunting of crack tips in the higher concentration of NaCl.

Figure 1
Investigation of Electrochemical Properties Between Titanium Scraps and Recycled Titanium
Authors: Jin Yun Ho , Yang Jae-Kyo 
Published: February 2020

Titanium has been widely used in various commercial fields. It has high strength, light weight, superior mechanical property at high temperature than any other metals. It also has good bio-compatibility and resistance corrosion property. However, titanium’s high material costs are limited to fields because of It plays a minor role in various applications due to high cost. Usually, thin oxide film were formed on titanium surfaces. The thickness of oxidized films were known as a few angstrom to nanometers.
Here in, titanium and its alloy (Ti-6Al-4V) scraps were collected by manufacturing process to recycle through acid-treatment routes. The acid-treatment process were consists of nitric acid and hydrofluoric acid. For comparison, we oxidized titanium and its scraps in high temperature in furnace and anodized to formed thick oxide films on titanium surfaces.
We analyzed its electrochemical properties by potentiodynamic polarization with potentiostat between scraps and recycled titanium. Ringer’s solution (9 NaCl, 0.24 CaCl, 0.43 KCl and 0.2 NaHCO3 in g/L) were used as electrolyte solution. The saturated calomel electrode (SCE) and graphite rode served as the reference and auxiliary electrodes, respectively. Potentiodynamic polarization tests were carried out at a scan rate of 500 mV/min from -250 ~ 3000 mV vs SCE with corresponds to open circuit potential (OCP).

Figure 1
Effect of Green Corrosion Inhibitors on the Corrosion Behaviour of Nanocrystalline W-42Cr-5Ni Alloy in 0.5 M NaCl Solution
Authors: Subedi Dhruba Babu 
Published: February 2020

A corrosion inhibitor is a chemical substance, which when added in a small concentration to a corrosive environment, effectively decreases the corrosion rate of a metallic substance that exposed to the environment (1). The corrosion control method of metals and alloys using the inhibitors is a fundamental academic and industrial concern that has received a considerable attention nowadays (2). Effects of three eco-friendly green corrosion inhibitors of sodium salts of nitrite, molybdate and tungstate in different concentrations (i.e., 200-2400 ppm) on the corrosion behaviour of the sputter-deposited ternary nanocrystalline W-42Cr-5Ni alloy were studied using corrosion tests and electrochemical measurements in 0.5 M NaCl solution open to air at 25ºC. The use of these corrosion inhibitors enhanced to increase the corrosion resistance properties of the alloys as a result the corrosion rate of the W-42Cr-5Ni alloy was decreased with increasing the concentrations of sodium nitrite from 200 to 2400 ppm as shown in Fig. 1(a). The inhibition action of the tested inhibitors was found to obey the Langmuir isotherm model and the inhibition efficiency was found to increase with increasing the inhibitors concentration. Based on the open circuit potential measurements, the most efficient corrosion inhibitor was found to be sodium nitrite than other sodium molybdate and sodium tungstate in 0.5 M NaCl solution open to air at 25ºC.

Uhlig, R. W. Revie, Corrosion and Corrosion Control; an Introduction to Corrosion Science and Engineering, 4rd edition, John Wiley and Sons, New York, 2008.

J. Bhattarai, Frontiers of Corrosion Science, 1st edition, Kshitiz Publ., Kathmandu, 2010.
The Adsorption and Corrosion Inhibition of Some Nonionic Surfactants on Carbon Steel and Brass in Aggressive Media
Authors: Branzoi Florina , Pacuretu Catalina , Branzoi Roxana 
Published: February 2020

The corrosion inhibition properties of some nonionic surfactants: Triton X100 and Triton A20, for two carbon steels (OL 37 and OLC 45) and brass in 1M H2so4 and 1M HCl was analyzed by weight loss method, potentiostatic and potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and metallurgical microscopy techniques.
The addition of the organic inhibitors led in all the cases to inhibition of the corrosion process in acidic solution at different temperatures. Under the critical micelle concentration (CMC), the inhibition of these three surfactants is negligible and at a concentrations higher than the CMC, the inhibiting action of these inhibitors increases rapidly.
The inhibition activity analysis of these organic inhibitors was made by assuming that the mechanism of inhibition by organic molecules is chemisorptions and physisorptions. We presume that, these organic compounds inhibit corrosion of carbon steels and brass by a protective mechanism, forming insoluble iron complexes, copper complexes and repairing the porous oxide layers. Polarization curves indicate that they are mixed type of inhibitors. The corrosion parameters obtained from polarization curves and from EIS spectra are in good concordance and point out the inhibitory action of cationic surfactants. The inhibition efficiency was high in all the studied cases. The adsorptions of the organic compounds on the carbon steels surface obeyed Langmuir’s isotherm. The thermodynamic parameters of adsorption enthalpy (ΔH0), adsorption free energy (ΔG0) and adsorption entropy (ΔS0) were calculated. The characterization using Fourier transform infrared spectroscopy (FT-IR) demonstrates the adsorption of organic inhibitors and the formation of corrosion products on the carbon steels and brass surfaces. The inhibition process was attributed to the formation of the adsorbed film on the metal surface and blocking the active sites that protects the metal against corrosive agents. The EIS measurements have confirmed this protection and pointed out the formation of adsorption layers on the electrode surface.
Nonlinear Cycling Aging of a Commercial 18650 Lithium Ion Cell
Authors: Wu She-huang , Lee Po-Han 
Published: February 2020

The capacity and power loss are usually observed when lithium ion batteries were cycled or stored, however, the degradation mechanisms and their correlation with cell performance fade are not only dependent on the cell chemistry but also on the cell design and manufacture technique. The capacity loss diagnosis and the lifetime prediction for LIBs are still critical issues for large format applications. Commercial 18650 lithium ion cells containing a composite cathode of LiNi0.5Mn0.3Co0.2 (NMC) and LiMn2O4 (LMO) and graphite anode with a nominal capacity of 2.15 Ah were used in this study. Although the aging behavior of the battery comprised with LiNi1/3Mn1/3Co1/3O2/LiMn2O4 composite cathode and graphite anode cycled between 4.2 and 2.8V had been studied with an incremental capacity technique and suggested that there are two stages of capacity fade with first stage mainly caused by the loss of inventory (LLI) and further suffered from loss of active material (LAM) in positive electrode in the second stage [1, 2]. The results of capacity retention study within the voltag
e range between 4.2 and 2.75V by following the manufacturer’s suggestion and charging the cells with CC-CV mode with 0.5C rate (cut-off at 0.04C) and discharging at 0.5, 1.0, and 2.0C rates, respectively, shown in Fig.1 (a), manifest that the cells cycled at higher discharge rate exhibit longer cycle life than that cycled at 0.5C. It is contrary to the generally accepted notion that high C-rate will accelerate cell aging. However, the expected tendency can be observed when cells were cycled between 4.2 and 3.0V (Fig. 1 (b)). From the results incremental capacity analysis (ICA) for the charge/discharge curves of the cells discharged at 1.0C rate with lower cut-off voltage of 2.75 and 3.0V, respectively, the redox peaks at around 3.53V, those relates with the amount of active graphite, decreases abruptly after 300th cycle where the accelerated capacity fade occurs for cell cycled between 4.2 and 2.75V.That suggests the accelerated capacity loss can be caused by loss of anode material instead of cathode material in additional to the continued loss of lithium inventory that can be observed from the shifting of the peak at around 3.53V to higher voltage and lowering of the peak at about 3.69V (Fig. 2). In order to understand the non-linear capacity fade when cells were cycled between 4.2 and 2.75V, post-mortem studies with XRD, SEM, ICP, and capacity retention for the electrodes obtained from fresh, 200 cycled, and aged cells will be performed for comparison with those of the cells cycled within 4.2 and 3.0V to support the results obtained from ICA.

Reference

[1] M. Dubarry, C. Truchot, M. Cugnet, B.Y. Liaw, K. Gering, S. Sazhin, D. Jamison, C. Michelbacher, Journal of Power Sources, 196 (2011) 10328-10335.
[2] M. Dubarry, C. Truchot, B.Y. Liaw, K. Gering, S. Sazhin, D. Jamison, C. Michelbacher, Journal of Power Sources, 196 (2011) 10336-10343.

Figure 1
Enhancement of High-Voltage Cyclability and Rate Capability in LiNi0.5Mn1.5O4cathodes
Authors: Teshima Katsuya , Satoshi Kida , Kim Dae-wook , Zettsu Nobuyuki 
Published: February 2020

Lithium ion secondary batteries are one of the most important energy storage systems because of their higher energy density and power density. In particular, many different types of cathode materials are studied for increasing capacity and cell potential. Spinel-type LiNi0.5Mn1.5O4 have been attracting significant attention due to higher redox potential, lower cost and low environmental load. The LNMO is possibly sorted into two type of spinel structure with different space group, ordered and disordered phase, which is typically identified due to formation of oxygen deficient, which cause reduction of Mn4+ to Mn3+ based on charge valance.
Disordered spinel structures could also lead to improved rate capability due to higher electronic conductivity and Li-ion diffusive of Mn3+ ion, However, too much concentration of Mn3+ lead to structural distortion and disproportionation, and which can be reduce cyclability. Thus, suitable Mn cation adjustment as well as surface stabilization with thin layer for insulating the direct contact with liquid electrolyte is one of important factor for advanced LiNi0.5Mn1.5O4 electrode.
In this work, we performed two ways for the enhancement of high-voltage cyclability and rate capability in LiNi0.5Mn1.5O4crystals through the substitution of F anion within oxygen deficient LiNi0.5Mn1.5O4-

d
.crystals as well as surface modification with self-assembled monolayer of fluorocabon containing organosilane compound. We further calculational studies on the effect of fluorine substitution on their LIBs characteristics, including rate capability and cyclability by using first-principle calculation.