bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneous spinal cord infarction: a practical approach
Authors: Thomas George , Alakbarzade Vafa , Sammaraiee Yezen , Cociasu Ioana , Dalton Catherine , Pereira Anthony C
Published: July 2022

Spontaneous spinal cord infarction is significantly less common than cerebrovascular disease. Because of the tight anatomical distribution of pathways in the cord, small spinal cord infarcts usually give more obvious symptoms and signs than similar lesions in the brain. Large epidemiological stroke studies have generally not included spinal cord stroke and so the incidence of vascular syndromes in the spinal cord is unknown. Management and prevention strategies for spontaneous spinal cord infarcts stem from small case series and case reports. Patient outcomes from spinal cord infarction are better with prompt recognition, timely management and prevention of associated medical complications arising from paraplegia, tetraplegia, neurogenic bladder and bowel dysfunction. The process of rehabilitation following spinal cord infarction is an evolving area.
End-of-life care of people with long-term neurological conditions
Authors: Nair Krishnan , Lee Mark , Hobson Esther , Oliver David , Husbands Emma
Published: July 2022

Guidance and protocols of end-of-life care have been directed towards the care of patients with cancer. It is possible to extrapolate some of these to people with long-term neurological conditions, but there are obvious differences. Neurological conditions have widely different time courses of progression, making the timing of these discussions challenging. The common issues around end-of-life care include knowing when to start discussions, approaching advance planning, managing common symptoms, diagnosing the dying phase, withdrawing life-sustaining treatments, providing support for family and carers and judging how to involve specialist palliative care teams. End-of-life care needs close collaboration between neurology, specialist palliative care and general practice.
Exact modifications on a vacuum spacetime due to a gradient bumblebee field at its vacuum expectation value
Authors: Poulis F. P. , Soares M. A. C.
Published: July 2022

This work belongs to the context of the standard-model extension, in which a Lorentz symmetry violation is induced by a bumblebee field as it acquires a nonzero vacuum expectation value. The mathematical formulation of a generic bumblebee model and its associated dynamical equations are presented. Then, these equations are considered for the vacuum and a substantial simplification is performed for the particular case of a gradient bumblebee field at its vacuum expectation value. After some further manipulation, a method to easily find solutions to the model is developed, in which the exact effect on the spacetime description due to the presence of this bumblebee field is explicitly provided. As some examples, the method is applied to determine the implications of the bumblebee field on the Schwarzschild spacetime and also on a rotating one. A previously published solution is recovered and some new ones are obtained. In the rotating situation, a simple solution is found which contains both the Kerr solution and the already published one as special cases. It is also shown its distinguished surfaces are still given by the same corresponding expressions for the Kerr solution. In conclusion, the mathematical improvement made is considered to be a significant contribution to the theory as a powerful tool to investigate its many aspects and consequences.
Wavelength-based Attributed Deep Neural Network for Underwater Image Restoration
Authors: Sharma Prasen , Bisht Ira , Sur Arijit
Published: July 2022

Background:
Underwater images, in general, suffer from low contrast and high color distortions due to the non-uniform attenuation of the light as it propagates through the water. In addition, the degree of attenuation varies with the wavelength, resulting in the asymmetric traversing of colors. Despite the prolific works for
underwater image restoration
(UIR) using deep learning, the above asymmetricity has not been addressed in the respective network engineering.

Contributions:
As the first novelty, this article shows that attributing the right receptive field size (
context
) based on the traversing range of the color channel may lead to a substantial performance gain for the task of UIR. Further, it is important to suppress the irrelevant multi-contextual features and increase the representational power of the model. Therefore, as a second novelty, we have incorporated an attentive skip mechanism to adaptively refine the learned multi-contextual features. The proposed framework, called
Deep WaveNet
, is optimized using the traditional pixel-wise and feature-based cost functions. An extensive set of experiments have been carried out to show the efficacy of the proposed scheme over existing best-published literature on benchmark datasets. More importantly, we have demonstrated a comprehensive validation of enhanced images across various high-level vision tasks, e.g., underwater image semantic segmentation and diver’s 2D pose estimation. A sample video to exhibit our real-world performance is available at
https://tinyurl.com/yzcrup9n
. Also, we have open-sourced our framework at
https://github.com/pksvision/Deep-WaveNet-Underwater-Image-Restoration
.
Prokaryotic Life in the Deep Ocean's Water Column
Authors: Herndl Gerhard J. , Bayer Barbara , Baltar Federico , Reinthaler Thomas
Published: July 2022

The oceanic waters below a depth of 200 m represent, in terms of volume, the largest habitat of the biosphere, harboring approximately 70% of the prokaryotic biomass in the oceanic water column. These waters are characterized by low temperature, increasing hydrostatic pressure, and decreasing organic matter supply with depth. Recent methodological advances in microbial oceanography have refined our view of the ecology of prokaryotes in the dark ocean. Here, we review the ecology of prokaryotes of the dark ocean, present data on the biomass distribution and heterotrophic and chemolithoautotrophic prokaryotic production in the major oceanic basins, and highlight the phylogenetic and functional diversity of this part of the ocean. We describe the connectivity of surface and deep-water prokaryotes and the molecular adaptations of piezophilic prokaryotes to high hydrostatic pressure. We also highlight knowledge gaps in the ecology of the dark ocean's prokaryotes and their role in the biogeochemical cycles in the largest habitat of the biosphere.
The Boston Keratoprosthesis—The First 50 Years: Some Reminiscences
Authors: Dohlman Claes
Published: July 2022

Millions of people worldwide are bilaterally blind due to corneal diseases including infectious etiologies, trauma, and chemical injuries. While corneal transplantation can successfully restore sight in many, corneal graft survival decreases in eyes with chronic inflammation and corneal vascularization. Additionally, the availability of donor cornea material can be limited, especially in underdeveloped countries where corneal blindness may also be highly prevalent. Development of methods to create and implant an artificial cornea (keratoprosthesis) may be the only option for patients whose eye disease is not suitable for corneal transplantation or who live in regions where corneal transplantation is not possible. The Boston Keratoprosthesis (B-KPro) is the most commonly implanted keratoprosthesis worldwide, having restored vision in thousands of patients. This article describes the initial design of the B-KPro and the modifications that have been made over many years. Additionally, some of the complications of surgical implantation and long-term care challenges, particularly complicating inflammation and glaucoma, are discussed.
(Invited, Digital Presentation) Carbon Nanotube, Electron Microscopy, and "Cinematic Chemistry"
Authors: Nakamura Eiichi
Published: July 2022

One hundred years ago, the "century of cinema" began, with images far superior to still images. However, even in the 21st century, molecular formulae and still images still play a leading role in the world of chemistry. In 2007, I reported an electron microscopic image of a process in which a hydrocarbon molecule undergoes a conformational change in a carbon nanotube (Science, 316, 853 (2007)), and this was the first movie capturing the motions of a molecule with a single-molecule atomic-resolution real-time electron microscopic (SMART-EM) technique. This marked the beginning of the era of "Cinematic Chemistry", where we can see with our eyes how chemistry takes place at an atomistic level (Acc. Chem. Res., 50, 1281-1292 (2017). In this lecture, I will report on the new paradigms of "cinematic chemistry", where carbon nanotube plays an essential role as a substrate on or in which the chemistry takes place. Examples will include single-molecule thermodynamics and kinetics based on ultra-fast imaging of individual molecules and reaction events, in situ structural and statistical analysis of crystal growth (JACS, 143, 1763-1767 (2021).

Figure 1
(Invited, Digital Presentation) Atomically Precise Synthesis of One-Dimensional Transition Metal Chalcogenides Using Nano-Test-Tubes
Authors: Nakanishi Yusuke , Furusawa Shinpei , Liu Zheng , Sato Yuta , Yomogida Yohei , Yanagi Kazuhiro , Suenaga Kazu , Miyata Yasumitsu
Published: July 2022

Since the discovery of fullerenes in 1985, nanocarbon materials have played a crucial role in materials science. Over the past decade, significant efforts have been directed towards exploring post nanocarbons. Two-dimensional (2D) layers of transition metal chalcogenides (TMCs) have been widely recognized as ‘beyond graphene’ due to their versatile chemistry. On the other hand, their 1D counterparts (nanowires, nanoribbons, and nanotubes) could exhibit the unique electronic properties, significantly distinct from the 2D layers as well as 1D nanocarbons (Fig. 1a).[1] However, exploring their potentials has been hampered by their limited availability. Although these materials have been prepared by using chemical and lithographic methods,[2] the reliable production of well-defined 1D TMCs remains a significant challenge.

Here we report atomically precise fabrication of 1D TMCs by using carbon/boron-nitride nanotubes (CNTs/BNNTs) as a template. Chemically and mechanically robust CNTs/BNNTs have increasingly been employed to promote and stabilize the bottom-up growth of 1D materials, allowing their facile handling and characterization. Isolation of a single MoTe/WTe nanowires inside CNTs enabled us to observe their dynamic torsions, which are not seen in the bulk (Fig. 1b).[3] Furthermore, we have utilized hollow spaces and external surfaces of BNNTs to produce a variety of 1D MX2 structures including single-walled MoS2NTs with the small diameter of ~1 nm. Electrically and optically insulating BNNTs can serve as an ideal ‘nano-test-tubes’ for precisely studying electronic properties of guest materials. The successful syntheses of 1D TMCs using CNTs/BNNTs might open up the possibilities for exploring unprecedented physics and potential applications.

Reference:

[1] a) G. Seifert et al. Phys. Rev. Lett.
1999, 85, 146. b) Y. Li et al. J. Am. Chem. Soc.
2008, 130, 16739. c) I. Popov et al. Nano Lett.
2008, 8, 4093. [2] (a) J. Kibsgaard et al. Nano Lett.
2008, 8, 3928. (b) X. Liu et al. Nat. Commun.
2013, 4, 1776. (c) P. Chithaiah et al. ACS Nano
2020, 14, 3004 [3] (a) M. Nagata et al. Nano Lett.
2019, 19, 4845. (b) N. Kanda et al. Nanoscale
2020, 12, 17185.

Figure 1
(Invited) Neuromorphic Devices and Systems Using Carbon Nanotubes
Authors: Akai-Kasaya Megumi
Published: July 2022

Molecular neuromorphic devices composed of single-walled carbon nanotubes (SWNTs) complexed with polyoxometalate (POM) exhibit various properties very similar to the functions of neurons. A random and extremely dense SWNT/POM network is expected to have the rudimentary ability of reservoir computing, which is a recently introduced framework derived from recurrent neural networks. We performed RC using multiple signals collected from a SWNT/POM random network. The results are expected to contribute to the design and fabrication of SWNT/molecular networks with high reservoir functionalities for future development. A physical reservoir consisting of nanomaterials may become a computing system with low cost, low power consumption, and highly integrated hardware devices for increasingly important edge computing.
(Invited) A Versatile Strategy for the Synthesis of Nanocarbon Molecules
Authors: Isobe Hiroyuki
Published: July 2022

Synthesis of molecules with large, curved π-systems attracts much interest, because of high expectations to deepen our understanding of nanocarbons. Many "nanocarbon molecules" are being synthesized via elaborate synthesis. However, due to challenging nature of the synthesis, the methods tend to be one-off and specific for one molecule. Herein we show our recent explorations of a versatile synthetic method adopting "phenine", which covers various shapes of large nanocarbon molecules. Synthesis of gigantic, 7-kDa nanocarbon molecules, defective nanotubes, bowls, saddles and hemispheres will be shown at the presentation.
(Invited, Digital Presentation) Ultra-Thin Organic Integrated Circuits Enabling Bio-Signal Monitoring
Authors: Sekitani Tsuyoshi
Published: July 2022

Digital technology has permeated our society, and a wide variety of electronic devices are now in use. In particular, the development of electronic devices for biometric measurements, such as wearable electronics, has been remarkable, and coupled with research and development of high-speed communication and artificial intelligence (AI), many social implementations are being presented. Our group has been conducting research and development on flexible and stretchable electronic systems, which are flexible, soft like rubber, and lightweight, by integrating functional organic nano-materials. In this research activity, our flexible and stretchable electronics have obtained certification for medical devices and are promoting the development of new electronics for use in medical institutions. In this presentation, I would like to introduce our recent activities on the flexible and stretchable electronics utilizing the nanoscience and technology, and developed low-noise and ultra-flexible systems for measuring biological action potentials (electroencephalogram; EEG and electrocardiogram ; ECG).
Operando Tracking of Ionic and Electronic Percolation in Electrodes for Energy Storage Application Using AC-in Plane Impedance
Authors: Maurel Victor , Taberna Pierre-Louis , Simon Patrice
Published: July 2022

Achieving efficient electronic and ionic electrode percolation is one of the most important parameters to improve batteries and supercapacitors power performance. Various electrical and electrochemical techniques (Cyclic voltammetry, Electrochemical Impedance Spectroscopy, EQCM, SECM, in-situ XRD, etc) can be used to assess the electronic and ionic transport properties in these electrodes. However, there are only few studies and techniques on tracking the change in resistance of an electrode during electrochemical polarization [1, 2, 3], which plays a key-role on its electrochemical performance.

In this study, we propose a new method to achieve operando resistance measurement under alternative current (AC), that we’ll call in-plane impedance measurement, under bias potential. In these experiments, the electrodes are deposited onto an insulating substrate so that, differently from conventional electrochemical impedance spectroscopy experiments, here the electrode in-plane conductivity is measured. Moreover, this method allows for distinguishing the ionic part of the in-plane electrode impedance from the electronic part that appears at high and low frequencies, respectively.

In this work, in-plane electronic and ionic transport properties of porous carbon (YP50F) and MXene (Ti3C2) electrode are studied while being fully charged or. During polarization, both the ionic and electronic percolation change with the applied potential for both electrode, that could be associated with electrode volume and conductivity change under potential and/or because of some doping caused by ionic specific electrosorption. This operando in-plane impedance measurement method furthers the fundamental understanding of ionic and electronic transport properties and may turn out to be effective tool to improve the electrochemical performances of capacitive, pseudocapacitive, or battery-like electrodes.

References:

[1] R.I. Tucceri. A review about the surface resistance technique in electrochemistry. Surface Science Reports 56 85-157 (2004).

[2] E. Pollak et al. The Dependence of the Electronic Conductivity of Carbon Molecular Sieve Electrodes on Their Charging States. J. Phys. Chem. B. 110 7443-7448 (2006).

[3] Yu. M. Vol’fkovich, et al. Surface Conductivity Measurements for Porous Carbon Electrodes. Russian Journal of Electrochemistry. 49 (6) 594-598 (2013).

Figure 1
All-Solid-State Lithium Metal Batteries Enabled By Solid Electrolytes with Low-Temperature Processability
Authors: Helms Brett , Bae Jiwoong , Yan Jiajun , Ko Youngmin , Zhu Zhuoying , Jain Anubhav
Published: July 2022

All-Solid-State lithium metal batteries are highly sought-after to improve the safety of high energy density batteries for electric vehicles, aircraft, and seacraft. Despite the proliferation of high-conductivity solid electrolytes, it remains a significant challenge to create conformal interfaces between them and the active materials in the battery. Furthermore, the poor electrochemical stability of known solid electrolytes often necessitates the co-design of protective coatings and interlayers, which increase cell resistance. Here, I will discuss a novel materials platform for advanced solid electrolytes that are readily processed at <150C, creating molecularly coherent interfaces with both lithium metal as well as a diverse selection of high-voltage storage materials and conductive carbons integrated in the cathode. I will describe how the composition may be tailored to achieve conductivity up to 10 mS/cm at ambient temperature. In stride, I will present electroanalytical and surface analytical characterization to define pathways for promoting or inhibiting the formation of interphases at the anode and cathode. Through control over interphases, we realize highly stable all-solid-state cells with >500 cycles with less than 80% capacity fade at current densities up to 1 mA/cm2 at an cell temperatures <45 C and stack pressures less than 0.5 MPa.
Design Considerations for Practical Li-S Battery Components for Electric Aviation
Authors: Dornbusch Donald , Viggiano Rocco P. , Wu James , Lin Yi , Connell John , Lvovich Vadim
Published: July 2022

The development of high-energy, high-safety, and high-power batteries beyond electric automobile requirements is vital for future electric aviation applications. The transition to non-volatile solid-state electrolytes (SSE) promises many advantages over traditional flammable liquid electrolytes and may also be an enabling technology for next generation chemistries. However, significant manufacturing challenges must be overcome before the adoption of such technology. This study focuses on advancement of previous electrolyte development to produce sulfide-polymer composites with densified thicknesses between 20-30 microns using a tape-casting technique with an elastomer binder [1]. Parameters such as binder type, binder loading, and filler loading are modified to determine their impact on electrochemical performance and mechanical stability. The composites were determined to retain reasonable ionic conductivity with improved flexibility and scalability critical for practical manufacturing of such cells. Films were produced 10-15 times thinner than comparable bulk powder electrolytes and within the range of commercial polyolefin separators (25 micron) used in commercial liquid containing lithium-ion cells. Composite conductivities were maintained above 0.2mS/cm, which holds promise for future electric aviation applications. Processing techniques are investigated to further improve electrochemical performance.

[1] Donald A. Dornbusch, Rocco P. Viggiano, John W. Connell, Yi Lin, Vadim F. Lvovich. Practical considerations in designing solid state Li-S cells for electric aviation, Electrochimica Acta, 2021, 139406, ISSN 0013-4686, https://doi.org/10.1016/j.electacta.2021.139406.
Topology Optimization of Flow Fields for Porous Electrodes
Authors: Lin Tiras Y , Baker Sarah , Duoss Eric B , Beck Victor A
Published: July 2022

Power-efficient energy storage is important for the successful integration of renewables into the electrical grid, and one promising storage device is the redox flow battery. In this presentation, we discuss the design of the flow field component of a redox flow battery using topology optimization. The flow field is a flow manifold that distributes and guides fluid with reactant both into and out of the reactive porous electrode. The popular two-dimensional interdigitated flow field, where a series of interlocking flow channels force fluid into the electrode, is a design that is commonly used in the lab, and we perform our optimization to improve upon this design. Specifically, we aim to minimize the electrical and flow pressure power losses, and we find that different operating conditions, i.e., flow rate and current density, lead to different optimal designs. We observe fully three-dimensional features in our optimized designs, where primary flow channels appear along with smaller branching channels that guide fluid to the electrode. This provides evidence that three-dimensional structures can provide improvement over conventional two-dimensional designs. While high power efficiency can certainly be attained using a traditional interdigitated flow field, the dimensions of the fluid channels and solid lands need to be carefully chosen for the desired operating conditions. In this presentation, we show that our method can computationally guide this design process.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL release number: LLNL-ABS-830167.
Physics-Based Use Case Analysis: Route Planning and Dynamic Load Prediction for Battery-Electric Buses
Authors: Eggleton Erica , Schwartz Daniel T.
Published: July 2022

The electrification of transportation and goods delivery networks, including ground, marine, and air, is becoming a reality around the world. These networks are logistically complex, and with this transition there is an added knowledge gap in the understanding of the energy storage system, such as lithium-ion battery packs. In Seattle, the local transit agency King County Metro is a national leader in transitioning to a fully electrified bus fleet and is the case study for this work. As transit agencies, such as King County Metro, adopt electrified vehicles, there are many new parameters that must be considered in route planning, fleet maintenance, and charging logistics. The literature shows that a longitudinal vehicle dynamics model can be used to estimate energy and load requirements along a route [1,2]. This work utilizes these known vehicle models, vehicle specifications, and battery information in a software tool. Software inputs include geographical information system (GIS) data, ridership data, and vehicle acceleration profiles. Model results allow the user to rank routes using metrics designed to consider route efficiency, vehicle performance, and known battery degradation events, such as regenerative braking and high-power discharge. This work also introduces how the battery state of charge, overpotential, current window, and deviations from equilibrium influence the route rankings. These results provide both systems-level and module-level insights beyond conventional vehicle and logistics models, allowing the user to make decisions that are predictive rather than reactive and can improve the lifetime of the batteries on-board.

[1] Gallet, M., Massier, T. & Hamacher, T. Estimation of the energy demand of electric buses

based on real-world data for large-scale public transport networks. Appl. Energy 230,

344–356 (2018).

[2] Asamer, J., Graser, A., Heilmann, B. & Ruthmair, M. Sensitivity analysis for energy

demand estimation of electric vehicles. Transp. Res. Part D Transp. Environ. 46, 182–199

(2016).
Computational Design of Porous Electrode Architecture for Electrochemical Flow Reactors and Redox Flow Batteries
Authors: Beck Victor A , Lin Tiras Y
Published: July 2022

Porous electrodes are utilized across electrochemical technologies including flow reactors and redox flow batteries. Controlling mass transport, conduction, and surface reaction in the electrodes is central to attaining peak device performance. Traditional methods often rely on manipulating the macroscopic electrode dimensions, device-level architecture, and flow distribution (e.g. via flow fields). However, beyond using traditional materials like felts or papers, engineering the internal electrode structure itself has recently emerged as a new design degree-of-freedom. These architected, porous electrodes are enabled by advanced and additive manufacturing techniques and are a promising route to provide greater control over the local transport and reactive environment, further improving device performance. New design tools will be necessary to fully exploit this expanded design space. Here we present a collection of computational design methodologies to automatically generate architected electrode design across scales. Resolved optimization techniques are used to determine optimal electrode architectures at the pore scale. Using homogenization, these techniques are then extended to scale-up the designs beyond typical benchtop dimensions. Using vanadium as a model chemistry, we demonstrate that the computationally designed electrodes yield improved performance across cost-functions and focus particularly on energy efficiency. Further, we analyze the resultant designs to highlight the structural features leading to improved performance.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

LLNL-ABS-830166
(Digital Presentation) A Zero-Dimensional Physics-Based Model for Lithium Carbon Monofluoride (Li/CFx) Batteries
Authors: Parke Caitlin D. , Harris Kailot , Albertus Paul
Published: July 2022

Lithium carbon monofluoride primary batteries have a high energy density (2180 Wh/kg of active materials based on the typical discharge potential) and low self-discharge. They have traditionally been used in medical devices like pacemakers with low rates of several years [1]. The high energy density of Li/CFx batteries also make them attractive for higher rate uses like aerospace or military applications; however, rate capability and heat generation can pose a significant challenge at higher rates. The theoretical potential of a CFx battery is around 4.5 V, but practical cells operate at 3 V or lower. The ~1.5 V overpotential is attributed to the strength of the C-F bonds, which results in slow kinetics and significant heat generation, especially when considering high rate (e.g., >C/10) and energy dense cell designs. Other challenges include the deposition of insulating lithium fluoride and large volume changes in each electrode [2].

Our work focuses on a high-energy density primary battery with a CFx cathode and lithium anode, designed for high rates with intermittent pulse power requirements. Physics-based modeling is an important tool that can clarify underlying mechanisms and help guide design to satisfy multiple constraints. To understand the challenges posed by this chemistry at higher rates, we have developed a zero-dimensional (0D) physics-based model that captures some of the complex phenomena within the CFx cathode. Included in the model are kinetics described by a concentration-dependent expression, changing porosity and electrochemical active area, and Nernstian thermodynamics. The model may also include a treatment of methods that increase the capabilities beyond the typical limits for the CFx chemistry. The implications of various conditions will be explored, such as the effect of the porosity and loading. The model results will be compared to experimental data from coin cells.

Acknowledgments

The authors would like to thank the Intelligence Advanced Research Projects Agency for funding this work.

References

Zhang, K. J. Takeuchi, E. S. Takeuchi, and A. C. Marschilok, Phys. Chem. Chem. Phys., 17, 22504 (2015).

S. Zhang, D. Foster, J. Wolfenstine, and J. Read, J. Power Sources, 187, 233 (2009).
Lorentz-Force-Mediated Zn Electrodeposition and Br- Ion Convection for Improved Performance in Aqueous Zn-Br2 Static Batteries
Authors: Sheelam Anjaiah , Glasco Dalton Lee , Bell Jeffrey Gordon
Published: July 2022

Redox flow batteries are one of the prominent electrochemical energy storage devices with large-scale storage and high energy density.1 The highly reversible Zn/Zn2+ (-0.76 V vs. RHE) and Br-/Br2 (1.08 V vs. RHE) redox couple have been employed in Zn-Br2 flow batteries (1.84 V vs. RHE). However, the dendritic growth of Zn electrodeposits during the repetitive discharge process triggers an internal short-circuit between the anode and the cathode.1 Besides this, cross-diffusion of the highly soluble Br- (Br3
-) ion causes a severe self-discharge of the system and reduced cycle life.2 Additives and ion-selective membranes have been employed to mitigate these challenges for improved cycle life and coulombic efficiency in Zn-Br2 batteries.3 Here, we fabricate an aqueous Zn-Br2 static battery with internally contained and moderate magnetic fields, (~ 30, 40, 50 and 60 mT) at the anode and cathode by incorporating 1 mm thick Nd permanent magnets. A solid complex of tetrapropylammonium tribromide was supported on activated carbon and employed as the positive electrode. Introducing a magnetic field can generate the Lorentz force (acting on Br- and Zn2+ ions), and create a controllable magnetohydrodynamic mass transport during the charge-discharge processes. Among the various magnetic fields, ~50 mT resulted in the highest coulombic efficiency (99 % for 100 cycles) and suppressed Zn dendritic growth. To rationalize the effect of magnetic fields on the efficiency and cycle life, Raman analysis, X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry (for the calculation of diffusion coefficient of Br- ion) are performed on the positive and negative electrodes of Zn-Br2 battery.

References:

(1) Z. Yuan, X. Liu, W. Xu, Y. Duan, H. Zhang, X. Li, Nat. Commun., 9
, 3731 (2018).

(2) L. Gao, Z. Li, Y. Zou, S. Yin, P. Peng, Y. Shao, X. Liang, iScience,
23, 101348 (2020).

(3) E. Sánchez-Díez, E. Ventosa, M. Guarnieri, A. Trovò, C. Flox, R. Marcilla, F. Soavi, P. Mazur, E. Aranzabe, R. Ferret, J
. Power Sources,
481, 228804 (2021).
(Invited) Actinide-Metal Interactions in Endohedral Fullerenes: An-an@C2n and an-M@C2n
Authors: Echegoyen Luis , Chen Ning , Poblet Josep M.
Published: July 2022

The existence of actinide-actinide (An-An) bonding interactions has been a controversial and actively researched topic in inorganic chemistry for many years. Calculations for An-An interactions inside fullerene cages (endohedral fullerenes) typically conclude that the weak interactions observed are the result of compression due to the presence of the carbon cage but these results and interpretations fail to address the mechanistic implications of the conclusions because they don't address the reasons why two An atoms would find themselves trapped inside a cage if they don't really like to interact with each other. How can we understand the prevalence of so many An-An@C2n as well as An-M@C2n endohedral compounds, some of which are obtained in very reasonable quantities, if there is no real driving force for their simultaneous incorporation inside the carbon cages. In this work we will present experimental and theoretical results that together show that there are reasonable metal-metal interactions inside these endohedral structures.
(Invited, Digital Presentation) Aggregation Switchable Fullerene-Peptides Conjugates
Authors: Ma Yue , Yamakoshi Yoko
Published: July 2022

Intensive research has been applied on chemical functionalization of fullerenes over the past decades, aiming at utilizing their broad availabilities in chemical biology field. Chemical moieties was induced to improve their water solubility and thus enhance their properties or interaction with biomolecules. In our previous study, we reported the synthesis of fullerene-PEG conjugates and demonstrated their ability for photoinduced DNA damage and ROS generation under visible light irradiation.

In this work, we report a water-soluble fullerene derivative by constructing a fullerene-peptide conjugates. The aggregation behavior as well as bio properties has been systematically studied for this series of fullerene-peptide conjugates (Figure 1a). By altering the attached peptides, fullerenes could exist as monomer or micelle in aqueous phase (Figure 1b).

Figure 1
(Invited) On-Surface Synthesis of Acene Polymers
Authors: Santos Jose , Jelínek Pavel , Ecija David , Martin Nazario
Published: July 2022

The design and study of π-conjugated polymers has received great attention along the last decades. The relevant optical and electronic properties stemming from their delocalised π-electrons allow for a number of applications in the emerging field of organic electronics. However, the inherent limited solubility of planar π-conjugated systems hinders their development, forcing chemists to introduce ancillary solubilising side-chains. On the other hand, ultrahigh-vacuum on-surface synthesis has become a powerful discipline that enables designing with atomistic precision a new plethora of molecular compounds, polymers, and nanomaterials that otherwise are unachievable by conventional organic chemistry.

Herein we present a novel on-surface chemical transformation that allows obtaining π-conjugated acene polymers from simple aromatic molecules carrying =CBr2 functionalities. The deposition of such precursors on an Au(111) surface gives rise to close-packed assemblies. Thermal annealing promotes the debromination of the species that thereafter homocouple and give rise to long anthracene wires linked by acetylene bridges, featuring a bandgap of 1.5 eV (see figure below).

When larger acenes or periacenes are used (i.e. pentacene, bisanthene, peripentacene) the resulting polymers undergo dramatic structural and electronic changes. Non-contact-AFM evince that the benzoid subunits evolve from aromatic (anthracene) to quinoid (pentacene, bisanthene...), while the alkyne linkers turn into cumulenic. The STM images allow witnessing the HOMO-LUMO levels crossing from anthracene to pentacene. This swap destabilises the aromatic structure and enables a biradical-quinoid one, that permit almost vanishing bandgaps below 0.35 eV. These findings can also be rationalised by topological band gap theory: DFT, tight binding and GW calculations predict that polymers these quasi-metallic polymers exhibit a topologically non-trivial electronic structure. Our results herald novel pathways to engineer π-conjugated polymers on solid surfaces, addressing the relevant family of acenes and, thus, contributing to develop the field of on-surface chemistry and to steer the design of modern low bandgap polymers.

Figure 1
(Invited) Multicomponent Reactions Towards New Fullerene and Metallofullerene Derivatives
Authors: Zhang Jianyuan , Li Yanbang , Sun Yue , Kopcha William
Published: July 2022

Fullerenes and endohedral metallofullerenes (EMFs) are molecular building blocks for a variety of organic materials widely applicable in photovoltaics, catalysis, quantum information science, semi-conductors, biomedicines, and so on. Regioselective functionalization reactions are essential for the construction of fullerene and EMF materials. Multicomponent reactions that generate reactive species to be captured by the double bonds on fullerenes or EMFs represent a useful approach to develop new reactions. In this presentation we hope to share our recent work in the development of new reactions for fullerene and EMF functionalizations, including isocyanide-induced reactions, reverse electron demand Diels-Alder reactions, and aminations.
(Invited) Toward the Isolation of Giant C120-C200 Fullertubes
Authors: Noble Cora A. , Koenig Ryan M , Ashcroft Chloe A. , Franklin Hannah M. , Bourret Emmanuel , Stevenson Steven
Published: July 2022

The newly reported purification and isolation of pristine and unfunctionalized C90 and C100 fullertubes has generated excitement due to their unique “hybrid” structure of ½-fullerene endcaps, but with a single wall nanotubular belt and mid-section. Unique features of these fullertubes include a (1) defined molecular weight, (2) reproducible structure, (3) pristine tubular belt region, and (4) natural solubility into organic solvents without functionalization or polymer wrapping. Hence, the surface of the fullertube belt region would inherently be smooth and free from surface coatings, derivatization, or oxidation. These features provide a unique molecular architecture for investigating the true nature of electronic and photophysical properties of the fullertube's tubular belt.

In this presentation, we will discuss our lab’s recent progress toward the isolation of segmentally longer fullertubes of higher aspect ratios as we seek to move from C120 fullertubes to C150 fullertubes and beyond.

Figure 1
(Invited) Synthesis and Optical Properties of Rod-Shaped Graphene Nanoparticles
Authors: Medina Lopez Daniel , Liu Thomas , Elias Christine , Rondin Loïc , Lauret Js , Campidelli Stephane
Published: July 2022

The scientific community has given much interest to graphene in recent years because of its good mechanical, thermal and electrical properties. Nonetheless, applications in optics and optoelectronics can be limited due to the absence of a bandgap. In order to engineer a bandgap, we can reduce the size of graphene into graphene quantum dots (GQDs). GQDs synthesis is primarily described via top-down methods (lithography, hydrothermal and electrochemical approaches).[1] Though effective, these methods do not allow accurate control of the size, shape and edges of the GQDs. On the other hand, bottom-up graphene materials have developed exponentially for the last decade with the synthesis of highly controlled graphene nanoribbon structures and moderately soluble graphene quantum dots.[2,3] Our group demonstrated that bottom-up GQDs could act as single-photon emitters exhibiting high brightness and stability.[4]

In order to investigate the structure-property relationship, we designed a series of rod-shaped graphene nanoparticles that differ only by their length, keeping the same morphology, symmetry and edge states (see figure). These nanoparticles are fully soluble, which facilitate their purification and individualization in solution and give rise to well-defined absorption spectra. Here we report on the synthesis of these GQDs, and we will present results on advanced characterization of their optical properties.[5]

[1] Yang, J.-S., Martinez, D. A. & Chiang, W.-H. Synthesis, Characterization and Applications of Graphene Quantum Dots in Recent Trends in Nanomaterials: Synthesis and Properties, Khan, Z. H., Springer Singapore, (2017).

[2] Narita, A., Wang, X.-Y., Feng, X. & Müllen, K. New advances in nanographene chemistry. Chem. Soc. Rev.
44, 6616–6643 (2015).

[3] Wang, X.-Y., Yao, X. & Müllen, K. Polycyclic aromatic hydrocarbons in the graphene era. Sci. China Chem.
62, 1099–1144 (2019)

[4] Zhao, S. et al. Single photon emission from graphene quantum dots at room temperature. Nat. Commun.
9, 3470 (2018).

[5] D. Medina-Lopez et al., submitted

Figure 1
Detection and Isolation of Isomerically Pure C120 Fullertubes
Authors: Noble Cora A. , Stevenson Steven
Published: July 2022

The emergence of macroscopic amounts of C60 fullerenes and carbon nanotubes in the 1990s has led to an explosion of growth in new structures of carbon nanomaterials. Over the last decades, there have been theoretical predictions of a particular “hybrid” family of mathematical structures. Fullertubes represent a new area of fundamental research in molecular carbon. They are similar to fullerenes in structure, but with increasingly long cylindrical, single-wall nanotube belts in the middle of the molecules. These nanotube belts are similar to single-layer, rolled graphene. In 2020 we published the isomeric separation and characterization of [5,5] C90-D5h fullertubes and [5,5] C100-D5d fullertubes. In this presentation, we will report and discuss the first isolation and UV-vis characterization of pristine and unfunctionalized C120 fullertubes. The separation and isolation of larger fullertubes is a two-step purification process. First, the spheroidal fullerene contaminants must be removed from the carbon soot extract to enrich the sample in fullertubes. Then in the second step, HPLC is used to achieve isomerically purified and pristine fullertubes. Efforts to characterize these newly isolated C120 fullertubes are currently underway.
Selective Solubility of Fullertubes with Non-Aromatic Solvents
Authors: Koenig Ryan M , Stevenson Steven
Published: July 2022

The recent experimental discovery of fullertubes has opened the door to fundamental studies in carbon nanomaterials. Fullertubes, comprised of half-fullerene end caps connected with a single-walled carbon nanotube belt, show evidence of the exciting properties of carbon nanotubes with the advantage of a defined, reproducible structure. However, large-scale quantities of these hybrid materials have yet to be realized due to their low abundance in electric arc extracts. Currently, fullertube isomers are isolated in two steps. In the first step, spheroidal fullerenes are reacted with aminopropanol and transferred to the aqueous layer in a separatory funnel. The unreacted fullertubes remain in the organic layer for subsequent HPLC purification. In this presentation, we introduce an intermediate step that exploits solubility differences between fullertubes and lower molecular weight fullerenes, further enriching their concentrations prior to HPLC separation.
Flexible, Freestanding, Bio-Compatible Electrodes for Integrated Supercapacitor
Authors: Ghodbane Myriam , Ashraf Juveiriah M. , Karam Zainab , Busa Chiara
Published: July 2022

On the route to sustainable technology and chemistries for bio-compatible energy storage devices, water-based formulations represent a promising alternative to the solvent now in use. Several polymer-based options, including poly(2-hydroxyethyl methacrylate) (poly[HEMA]) and silicon hydrogels show excellent biocompatibility, good mechanical properties and durability.

Alongside, in supercapacitors and batteries, carbon nanotubes (CNTs) and carbon nanostructures (CNSs) are a versatile alternative to the consolidated graphitic electrode. CNTs are well-known to provide excellent mechanical properties together with electrical conductivity and large surface area.

In this work, we introduce a novel concept for integrating freestanding CNTs-based energy storage system within hydrogels, preventing direct exchange with the environment. A systematic approach in regards with the electrochemical performances (CV, GCD, EIS) and the mechanical properties identifies favourable geometries for full systems, among several solutions.
Construction of Hybrid Coating Layer for Robust Zinc Anodes
Authors: Deng Wenjing , Wang Xiaolei
Published: July 2022

The environmental pollution and energy crisis require the development of large-scale energy storage techniques. Batteries have attracted enormous attention over the past several years due to their relatively long cycle life and high energy density . Lithium-ion batteries as the most widely used energy storage devices still have safety hazards, high cost issues. Zinc-based rechargeable batteries, have gained remarkable attention as a promising energy storage technology, especially in mild/neutral aqueous electrolytes. Aqueous zinc-ion batteries are promising candidates for the next-generation energy storage system. Zinc metal anode exhibits high theoretical capacity (820 mA h g-1), low redox potential (-0.76 V vs the standard hydrogen electrode), low cost, and intrinsically high safety. However, practical application limited by severe dendrite formation, corrosion and hydrogen evolution on the anode surface. They can cause low Coulombic efficiency, short cycling life and even puncture of separators or short-circuit in the batteries. One of efficient strategies toward improving reversibility of Zn anode is to use surface engineering strategies such as building an artificial coating protection layer for zinc-electrolyte interface to provide defined and smooth Zn depostion behavior. In this work, we designed and synthesized an inorganic-carbon composite protection layer by complexing zinc oxide with carbon. This composite protection layer not only effectively shields rampant electrolyte diffusion to suppress side reactions but also suppresses Zn dendrites by uniform Zn plating/stripping. Symmetric cells with hybrid coating layer show extended cycle life and small voltage polarization. Full batteries with Mn-based and V-based cathodes can be assembled with increased capacity and stable cycling performance.
Failure Analysis of Nickel-Coated Anodes in Zinc-Air Hybrid Flow Batteries
Authors: Hu Hang , He Anqiang , Ivey Douglas , Aasen Drew , Arfania Sheida , Shukla Shantanu
Published: July 2022

A zinc-air flow battery system pumps "fuel” (a zinc particle/KOH slurry) from a fuel tank to a fuel cell stack, where the zinc particles are combined with oxygen from the air to form zincate ions and produce electricity. The zincate-rich electrolyte is then returned to the fuel tank. During the charging cycle, the electrolyte is passed to the zinc regenerator, where electricity (from renewable sources such as solar or wind) is utilized to convert the zincate ions to zinc particles. The regenerated fuel is pumped back into the fuel tank for the discharge process.

Nickel is considered for use as the anode during zinc regeneration as it has been shown to be an active catalyst for the oxygen evolution reaction (OER). However, nickel electrodes pose manufacturing challenges due to machinability issues. Alternatively, nickel can be coated on a machinable metal substrate to improve scalability. These electrodes are subjected to open circuit voltage (OCV), OER, and the hydrogen evolution reaction (HER) during operation of zinc-air flow batteries. The electrodes have been observed to fail during prolonged voltage cycling due to nickel coating delamination, which manifests itself as blistering, flaking, and discoloration. It is hypothesized that this may be due to electrolyte penetration into the pores of the nickel coating during operation. The present work is aimed at analyzing and mitigating the coating delamination process through characterization of various Ni coating recipes. As-fabricated and cycled electrodes are characterized using various microstructural techniques, including optical microscopy, x-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), and x-ray tomography. Coated electrodes are also evaluated electrochemically and the results are correlated with the microstructural analysis. The overall goal of the work is to understand the failure mechanisms and apply the knowledge to fabricate improved coatings for OER electrodes.