bluuebunny/crossref_metadata_2025_split huggingface dataset:
Operando study of Chemical and Structural Evolutions of TiS2 in Li-Ion and Na-Ion Batteries
Authors: Lin Cheng-Hung , Sun Ke , Attenkofer Klaus , Topsakal Mehmet , Bai Jianming , Zhao Chonghang , Lu Deyu , Dooryhee Eric , Stavitski Eli , Northrup Paul , Gan Hong , Chen-Wiegart Yu-chen Karen 
Published: February 2020

Since the first report of the inserting reaction of alkali metals in layered dichalcogenides in 1959, titanium disulfide (TiS2) has been widely studied as a model material of intercalation host compound in energy storage for Li-ion batteries. Due to its high electric conductivity, fast rate capability, good cycling performance and natural abundance, TiS2 electrode also became a promising candidate for the low-cost Na-ion battery system. However, the differences regarding the detailed chemical and structural evolutions and reaction mechanism of TiS2 in Li-ion and Na-ion batteries are not yet well understood. In this work, the chemical and structural evolutions of TiS2 in both Li-ion and Na-ion batteries are investigated via operando synchrotron absorption spectroscopy (XAS) at both the sulfur and titanium K-edges using complementary hard x-rays and tender x-rays at the National Synchrotron Light Source II. By combining X-ray diffraction and operando XAS with the Multivariate Curve Resolution - Alternating Least Squares (MCR-ALS) method, we reveal the chemical speciation during the electrochemical cycling. Our study also sheds light on the reaction mechanism of Na-TiS2, which is compared with that of the Li-TiS2 system.
ACKNOWLEDGMENT
We thank DOE Office of Energy Efficiency and Renewable Energy under the Advanced Battery Materials Research (BMR) program, Contract No. DE-SC0012704; we thank ISS, TES, and XPD beamlines of NSLS-II, supported by DOE Office of Science. This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704. Funding was supported by Stony Brook University and Brookhaven National Laboratory.
Figure: An illustration of the structural and chemical evolutions during sodiaiton observed by operando XAS and ex situ XPD approaches.

Figure 1
Synthesis of Rice Ball Shaped Rare Earth-Carbon Composite Electrode Material for Lithium-Ion Batteries
Authors: Lee Seunghyun , Park Chong-Yun , Son Yongkeun 
Published: February 2020

The CeO2, known as one of the typical rare earth oxides, is seen to have considerable potential for being used as novel anode materials for secondary batteries because it shows excellent electrochemical redox properties. When it is considered as an anode material, the foremost advantages are that its volumetric and morphological changes are hardly observed, so it could provide good stability and longevity of secondary batteries. It is well explained by the fully reversible phase transformation between fluorite structured CeO2 and cubic structured Ce2O3 during the electrochemical reaction.
Nonetheless, it is essential to improve the conductivity problem of the CeO2 which has intrinsically low electron conductivity in order to apply it to secondary batteries. Meanwhile, there used to be a widely used method called carbon composite method to support nonconductive metal oxides.
In this study, we have synthesized the CeO2-Carbon composite sphere in the form of rice balls to improve the conductivity problems of the rare earth oxide during their electrochemical performance. A rice ball structure is expected to provide more advanced electronic conductive networks than a core shell structure does. Indeed, high stability was observed during the charging and discharging process of LIB due to the nanostructures in the form of rice balls.
(Invited) Controlling Energy Transport in Tailored Carbon Nanotubes Networks for Energy Harvesting Applications
Authors: Ferguson Andrew John , Blackburn Jeffrey L. 
Published: February 2020

The ability to selectively extract semiconducting single-walled carbon nanotube (s-SWCNT) species from the raw material with high fidelity is leading to their incorporation as elements in a variety of optical and electronic applications. We have recently employed conjugated polymers based on the fluorene chemical moiety to produce tailored s-SWCNT samples that can be incorporated into photovoltaic, thermoelectric, and transistor architectures.
By controlling both the extent of carbon nanotube bundling and/or removing the insulating polymer that wraps the individual carbon nanotubes, we explore the complex effects of these morphological modifications on the transport of energy by excitonic species and charge carriers in enriched s-SWCNT networks. We show that removal of the insulating polymer, which is often strongly bound to the carbon nanotubes through van de Waals forces between the π-electron systems of the two components, results in a significant improvement in charge carrier transport. In contrast, exciton transport is subtly dependent on the specific nanotube-nanotube interactions in the network. For instance, exciton energy transfer to minority low-bandgap species within a bundle is extremely efficient, but this often traps the exciton in an individual bundle, thereby inhibiting long-range transport within the network.
As alluded to above, the performance of carbon nanotubes in these applications is sometimes strongly dependent on the interplay between the optical and electronic properties of the s-SWCNT networks, which can be controlled by tuning the charge carrier density. We have developed a number of processes that allow us to exert fine control over the charge carrier density injected by redox-active chemical dopants, including the ability to controllably dope the s-SWCNT network p-type and n-type. We will discuss how these strategies can be exploited to exert fine control over charge-carrier transport in the doped s-SWCNT networks, allowing us to target the optimum doping level for the desired application.
Finally, we will discuss the implications of our findings within the context of the incorporation of enriched s-SWCNT networks in energy harvesting applications.
Polyluminol Modified Carbon Nanotube Electrodes for Electrochemical Capacitors
Authors: N'Diaye Jeanne , Lian Keryn 
Published: February 2020

Luminol exhibits electrochemical redox activity when electropolymerized on various substrates, and has been used for electrocatalysis and biosensors [1, 2]. This electrochemical behavior is due to the presence of different amine functional groups within the polymer structure. Recent studies have shown that introducing amine groups on a carbon surface improves the charge storage capacity and the conductivity of the obtained material [3]. Our work aims to leverage the electrochemical properties of polyluminol (Plum) for electrochemical capacitors (ECs). Firstly, the Plum was synthesized using a chemical approach and characterized using spectroscopic methods and electrochemical analyses. Secondly, the polymer was deposited on carbon nanotubes (CNT) to enhance the charge storage capacity for ECs.
The chemical composition of the polymer was found to be a mixture of benzoid and quinoid segments, bonded via secondary (NH) or tertiary amine (=N-) groups, respectively. Such functionalities facilitated chemical, thermal, and electrochemical stability of the polymer. The composite electrode material was obtained by in-situ chemical polymerization of Plum on CNT. Morphological analyses of CNT confirmed the increase of the Plum thickness on CNT with polymerization time, reaching a saturation point of 6.5 nm. In addition, a 4x increase of charge storage capacity with good electrode stability was observed compared to bare CNT over a potential window of 1.2 V as seen in figure 1. Study of the redox reaction kinetics revealed a mostly capacitive contribution of the polymer on CNT. This work showed the successful surface modification and engineering of CNT using a simple and effective fabrication method, which is suitable for large-scale fabrication of composite electrode materials for ECs.

G.-F. Zhang and H.-Y. Chen, Analytica Chimica Acta, 419, 25 (2000).

A. Sassolas, L. J. Blum and B. D. Leca-Bouvier, Sensors and Actuators B: Chemical, 139, 214 (2009).

N. Phattharasupakun, J. Wutthiprom, P. Suktha, N. Ma and M. Sawangphruk, Journal of The Electrochemical Society, 165, A609 (2018).

Figure 1
A Nanobioengineering Frontier for Next-Generation Optical Devices
Authors: Boghossian Ardemis Anoush 
Published: February 2020

The vast expansion of available synthetic biology tools has led to explosive developments in the field of materials science. No longer confined to engineering just synthetic materials, the increased accessibility of these tools has pushed the frontier of materials science into the field of engineering biological and even living materials. By coupling the tunability of nanomaterials with the prospect of re-programming living devices, one can re-purpose biology to fulfill needs that are otherwise intractable using traditional engineering approaches.
Optical technologies in particular could benefit from capitalizing on untapped potential in coupling the optical properties of nanomaterials with the specificity and scalability of biological materials. This presentation highlights specific applications in optical sensing and light-harvesting energy technologies that exploit the synergistic coupling of nanobio-hybrid materials. We discuss the development of bio-conjugated single-walled carbon nanotubes (SWCNTs) for near-infrared fluorescence sensing and the application of these nanobioptic sensors for continuous measurements in living cells and organisms. We further explore the development living photovoltaics based on bioengineered, photosynthetic organisms with augmented capabilities.
Multifunctional NIR-Fluorescent Carbon Nanotubes for Imaging and Sensing By Using Defect Chemistry
Authors: Herrmann Niklas , Mann Florian , Kruss Sebastian 
Published: February 2020

Single-walled carbon nanotubes (SWCNT) are versatile materials for imaging and sensing in the near infrared (nIR) range. Non-covalent adsorption with (bio)polymers such as ssDNA is a powerful approach to functionalize SWCNTs. This approach lead to sensors that detect the release of biomolecules such as neurotransmitters from cells with high spatiotemporal resolution. However, covalent approaches would be beneficial for many applications because of higher stability and photophysical signal transduction. It has been reported that reactions with diazonium salts create covalent defects and a red-shifted peak in the nIR fluorescence spectrum attributed to a formerly dark exciton.
Here, we use defect chemistry to covalently modify SWCNTs and at the same time change their fluorescence spectrum in a well-defined way. For that purpose, we synthesized a maleimide-carrying diazonium salt and used a light-catalyzed reaction to introduce defects. The maleimide group can be further functionalized using thiols in a thiol-en click reaction. The modified SWCNTs were additionally wrapped in DNA for solubilization and characterized via nIR spectroscopy and atomic force microscopy (AFM). Our results show that depending on the attached thiol compound these SWCNTs respond differently to small molecules such as the neurotransmitter dopamine. This approach was then used to optimise the selectivity profile and sensitivity for fluorescent sensing applications. Furthermore, we covalently conjugated antibodies to the SWCNTs and used them for nIR labeling in cells.
In summary, we present a new approach to covalently functionalize SWCNTs using defect chemistry and demonstrate applications in nIR imaging and sensing.
(Invited) Emerging Neuromorphic Devices for Carbon Nanotubes and Related Low-Dimensional Materials
Authors: Hersam Mark C. 
Published: February 2020

The exponentially improving performance of conventional digital computers has slowed in recent years due to the speed and power consumption issues that are largely attributable to the von Neumann bottleneck (i.e., the need to transfer data between spatially separate processor and memory blocks). In contrast, neuromorphic (i.e., brain-like) computing aims to circumvent the limitations of von Neumann architectures by spatially co-locating processor and memory blocks or even combining logic and data storage functions within the same device. In addition to reducing power consumption in conventional computing, neuromorphic devices also provide efficient architectures for emerging applications such as image recognition, machine learning, and artificial intelligence. With this motivation in mind, this talk will explore the opportunities for carbon nanotubes and related low-dimensional materials in neuromorphic devices. For example, by combining p-type semiconducting carbon nanotubes with n-type two-dimensional transition metal dichalcogenides, gate-tunable diodes have been realized, which show anti-ambipolar transfer characteristics that are suitable for artificial neurons, competitive learning, and spiking circuits [1]. In addition, by exploiting field-driven defect motion mediated by grain boundaries in monolayer MoS2, gate-tunable memristive phenomena have been achieved, which enable hybrid memristor/transistor devices (i.e., "memtransistors") that concurrently provide logic and data storage functions [2]. The planar geometry of memtransistors further allows multiple contacts to the channel region that mimic the behavior of biological neurons such as heterosynaptic responses [3]. Overall, this work introduces new foundational circuit elements for neuromorphic computing in addition to providing alternative pathways for studying and utilizing the unique charge transport characteristics of low-dimensional materials [4].
[1] V. K. Sangwan, et al., Nano Letters, 18, 1421 (2018).
[2] V. K. Sangwan, et al., Nature Nanotechnology, 10, 403 (2015).
[3] V. K. Sangwan, et al., Nature, 554, 500 (2018).
[4] D. Jariwala, et al., Nature Materials, 16, 170 (2017).
Improved Performance of Carbon Nanotube Based Strain Sensor
Authors: Kim jae Keon , Lee Junyeop , Jung Daewoong 
Published: February 2020

Strain sensor has been used in variety of industrial applications for structural healthy monitoring and biological signal analysis. The fabrication of a highly sensitive strain sensors are underwent many complex and delicate processes, as many fabrication parameters and conditions must be keep equilibrium to achieve good sensor performance, such as high linearity and sensitivity, stable responsivity, fast response time, mechanical durability, and signal processing steps [1].
Carbon based-nano materials such as fullerene, carbon nanotube (CNTs), and graphene have been considered as sensing materials for optical sensor, chemical sensor, physical sensor and environmental sensor, which possess their own strengths and weakness.
Especially, CNTs have been widely employed as sensing species for strain/pressure, gas, temperature, and humidity sensor in recent years. CNT-based sensors were generally fabricated by transferring the individual or bundles of CNTs to the substrates using spin-coating, spraying, dip coating, and inkjet printing methods [1-2].
On the other hand, spin-capable CNTs were reported previously, which simply make transparent conductive CNT webs, ribbon or yarns. The spin-capable CNT forest can give an easy and effective way to fabricate highly-aligned CNT yarn with high flexibility and a electrical conductivity for sensor applications [1-3].
In this paper, we present performance of the CNT yarn based strain sensor. Especially, CNT yarn was associated with stretchable polymers to apply tensile and compressive force. The experimental results reveal that CNT yarn with elastic rubber can be stretch up to 300 %.
References

Jung et al, J. Vac. Sci. Technol.
32 (2014), 04E107.

Han et al. Microelectron. Eng., 168 (2017), 50-54.

Jung et al., J. Sensors. Sci. & Tech,.
22 (2013), 315-320
Metal-Ionic Phase Reactions in Molten Salt Ionic Liquids: Experimental, Thermodynamic and Kinetic Analysis of the Alteration of Preformed-Oxides on Fe-Cr Alloys
Authors: HAN Junsoo , Wartenberg Marlene Grace , Scully John R. 
Published: February 2020

Abstract

The object of this research is to develop a better experimental, thermodynamic and kinetic understanding of effects of various “harsh” environments on the passive preformed-oxide developed on model structural materials. Ultimately the passive oxide layer governs corrosion processes in molten salts. To this end, systematic studies were conducted on a range of model alloys from Fe to Fe-Cr and Cr as well as Ni and Ni-Cr alloys after passivation in aqueous solutions or by thermal “pre-oxidation in air”. The tested materials were Fe-8Cr, Fe-18Cr binary alloys and nominally pure Fe, Cr as reference metals. These model alloys were subsequently exposed to halide containing aqueous solutions, room temperature and high temperature ionic liquids with various salt species and impurities added in isolation. These may alter or dissolve the preformed-oxide film and ultimately govern the corrosion behavior. The final goal of this project will be to improve the scientific understanding using selected multi-component and model materials in classes of ionic liquids (molten salts) with and without radiation. Experiments have been focused on the non-irradiated materials to date. However, the irradiated materials will also be investigated in various molten salts and room temperature ionic liquids.
The specimens were tested in a borate buffer solution to form a passive oxide layer (2~5 nm thickness) without forming compounds with elements of structural materials. This oxide layer was firstly analyzed in an aqueous chloride containing solution in order to understand its electrochemical properties under more common aqueous condition. Thermally grown pre-oxides at various temperatures, T = 200, 400, 600 and 800°C, and oxides designed by controlled sputter deposition were also investigated. Diagnostics was used to elucidate the type of films on metals, the growth rate and the controlling factors as a function of driving force such as formation potential or temperature. Electrochemical impedance spectroscopy (EIS) was used to first characterize the preformed-oxide. Capacitance and Mott-Schottky plots were utilized in order to quantify film thickness, growth rates versus time, semiconductor dopant type and defect density. Altered oxides and intact oxides were also characterized by XPS and FIB TEM analysis. Changes in these attributes as a function of time of exposure of preformed-oxides to ionic liquids and molten salts will be discussed.

Acknowledgments

This work was supported as part of Fundamental Understanding of Transport Under Reactor Extremes (FUTURE), an Energy Frontier Research Center (EFRC) funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences.

Figure 1
Process Intensification Approaches to Organic Electrosynthesis: Towards Sustainable Nylon Production
Authors: Modestino Miguel Antonio , Blanco Daniela Eugenia 
Published: February 2020

The effect of fossil-fuel-derived carbon dioxide (CO2) emissions on the environment has fueled the interest in electrifying the chemical industry through electrochemistry. The implementation of electrochemical processes for the production of large volume chemicals can allow for the direct integration of renewable energy sources into chemical manufacturing. Additionally, these processes provide an opportunity for significant energy efficiency improvements and the introduction of previously unexplored chemical transformations. Although inorganic electrosynthetic processes have been successfully implemented in industry at scale (e.g. chloro-alkali and Aluminum production), the use of electrochemical methods for the production of organic chemicals has been limited, even if their potential impact is significantly larger.
In spite of their advantages, organic electrosynthetic processes face common challenges such as limited reactant concentrations in the electrolyte, a complex set of competing organic side reactions, and the narrow electrochemical stability window of aqueous electrolytes.1 The low solubility of organic reactants, together with the use of high current densities that maximize reaction throughput, often result in mass transport limitations that can lower reaction selectivity. As a model case study, this work focuses on the electrohydrodimerization of acrylonitrile (AN) to adiponitrile (ADN), a precursor to Nylon 6,6.2 Although this is considered the largest and most successful organic electrosynthesis implemented in industry, it faces many challenges owing to its limited energy conversion and selectivity. Through a combination of experimental insights and artificial-intelligence-enabled models, we elucidate process intensification guidelines for mass transport enhancement in organic electrosynthesis via electrolyte optimization, complex voltage dosing, and membrane-based electrochemical flow reactors. Moreover, this work explores the development of the sequential electro-hydrogenation of ADN to hexamethylenediamine (HMDA), paving the way for a continuous electrochemical process for the production of Nylon monomers. Our results provide insights on the main challenges faced in organic electrosynthesis, and demonstrate how innovative process intensification approaches can address these challenges and enhance the competitiveness of electrochemical routes for the production of valuable organic chemicals.

Blanco, D. E.; Modestino, M. A., Organic Electrosynthesis for Sustainable Chemical Manufacturing. Trends in Chemistry
2019,
1 (1), 8-10.

Blanco, D. E.; Dookhith, A. Z.; Modestino, M. A., Enhancing selectivity and efficiency in the electrochemical synthesis of adiponitrile. Reaction Chemistry & Engineering
2019,
4 (1), 8-16.