bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aqueous Carbon Suspensions for Electrochemical Applications
Authors: Muller Guillaume , Petrissans Xavier , Giaume Domitille , Laberty-Robert Christel , Barboux Philippe 
Published: February 2020

We report the transport properties and mechanical behaviors of carbon inks as a conductive component in semi-solid electrodes. Commonly, the suspensions show a gel-like behavior implying the percolation of the solid network. Our work shows the dependency of rheological and conductivities properties on the carbon concentration, morphology, as a function of shear rate. Different percolating thresholds are found as a function of pH and ionic strength that act on the surface charge of the particles and their coulombic interaction. Under shear flow, the suspensions commonly exhibit a three-regime flow curve: shear-thinning at low and high shear rates separated by a small increasing-viscosity region over intermediate rates. These results are strongly dependent of the nature of the carbon slurry and measurement conditions. The highest conductivity can be obtained by tuning these parameters. The rheo-electrical behavior of aqueous carbon suspension shows the possibilities and limitations of semi-solid aqueous inks as flowable electrodes for two different technological applications such as redox flow batteries and electrowinning.
First, semi-solid aqueous redox flow batteries are discussed in this work for safety, toxicity, cost and reliability. Such as flow-cell concept was recently described by Yet-Ming Chiang’s group at MIT in 2010 [1]. They proposed using typical intercalation electrode materials as active materials for a lithium rechargeable battery, but providing the active material in a slurry that can be mechanically pumped into and out of a reaction chamber. A redox flow batteries (RFBs) using intercalation electrode materials as active materials for a lithium rechargeable battery (such as “MIT suspension redox flow” batteries).
Second, we discuss the use of such conductive pastes for extraction of various metals such as copper from various mineral ores. The conductive inks can be mixed with powdered ores and permit an electrical percolation that allow electrochemical dissolution of the materials. We analyze the electrochemical yield as a function of the copper concentration and formulation of the carbon paste before we discuss the applications.
[1] M. Duduta, B. Ho, V.C. Wood, P. Limthongkul, V.E. Brunini, W.C. Carter, Y. Chiang, Semi- Solid lithium rechargeable flow battery, Advanced Energy Materials 1 (4) (2011) 511.
Discharge Behavior of Si-Air Batteries with Aqueous Electrolyte
Authors: Durmus Y. Emre , Kayser Steffen Alexander , Aslanbas Özgür , Tempel Hermann , de Haart L.G.J. , Granwehr Josef , Kungl Hans , Eichel Rüdiger-Albrecht 
Published: February 2020

A recent concept of metal-air batteries, Si-air, has a good potential to play a major role in the primary battery market due to possessing the second most abundant element in Earth’s crust as an anode. The main drawback of this system is the low practical discharge capacities both in aqueous alkaline and room temperature ionic liquids. In the previous studies, limitation of discharge is suggested to originate from a formation of an oxide layer on the Si surface, which prevents further oxidation of the active material.1,2,3 Additionally, there is a high corrosion rate of Si in aqueous systems that results in low anodic mass utilization efficiencies.
The main objective of current work is to find an approach to overcome the discharge limitations in aqueous alkaline systems. Electrochemical characterizations of Si-air cells were carried out by galvanostatic discharge experiments with Si wafers under controlled ambient conditions. The complete consumption of the active Si in the cell was achieved when a suitable setup, i.e. sufficient electrolyte, was employed. Discharge behavior of the Si-air cells was also investigated along with variations of temperature and molarity of alkaline electrolyte.
Since large amounts of the Si mass were consumed in the corrosion reaction during the experiments, the current work focuses also on corrosion studies. From the data on Si anode mass and discharge capacities, the corrosion rate and anodic mass utilization efficiencies were calculated. To have a better insight into the corrosion mechanism, nuclear magnetic resonance experiments were performed on the Si dissolution in alkaline electrolyte. From these experiments, formation of different Si-O-H silicate species as products of the corrosion reaction was identified. Moreover, the effect of corrosion products on the discharge performance and corrosion rate was studied as well. Based on the experimental results, specific discharge capacities of Si-air batteries are discussed while taking the corrosion process into account.
In summary, in spite of the corrosion process, the main goal to overcome the discharge limitations was accomplished by complete consumption of the active Si during the discharge. The effect of corrosion products on the discharge performance was investigated and the results will be reported.
References
1. Cohn, G., Eichel, Rüdiger-A., Ein-Eli, Y. Phys. Chem. Chem. Phys. 15, 3256–63 (2013).
2. Zhong, X., Zhang, H., Liu, Y., Bai, J., Liao, L., Huang, Y., Duan, X. ChemSusChem 5, 177–80 (2012).
3. Park, DW., Kim, S., Ocon, JD., Abrenica, GHA., Lee, JK., Lee, J. ACS Applied Materials & Interfaces 7, 3126–3132 (2015).
Novel Inorganic Coatings for Li2s Cathodes
Authors: Medina Ulises 
Published: February 2020

While Li2S cathodes are extremely attractive due to their high theoretical capacity (1166 mAh/g), low cost, and compatibility with non-lithium metal anodes, the lithiation/delithiation reaction pathway between Li2S and S includes the formation of soluble polysulfides, which leads to poor cycle life. One strategy to improve cycle life is to coat Li2S particles with a protective layer, preventing polysulfide dissolution.
Leveraging a proprietary high-throughput synthesis workflow, Wildcat Discovery Technologies has demonstrated the reactive deposition of an inorganic coating onto Li2S particles. The coating method, based on the reaction of precursors with Li2S, is shown to be a general method and used to deposit coatings with different compositions on the surface of Li2S. Galvanostatic cycling of coated cathodes shows reduced formation of soluble polysulfides which in turn increases cycle life with 95% capacity retention between cycles 1-3 and also improves long term cycle life. This coating also improves conductivity thus improving cycle 1 discharge capacity. The approach described in this presentation is unique in: 1) it focuses on the charged state of the cathode versus the uncharged state (Li2S vs S) which would enable cell chemistries that do not rely on a Li metal anode, 2) it is a novel type of coating for the active material which is compatible with any base Li2S, and 3) demonstrates the power of high-throughput screening in developing new chemistries for next generation batteries.
Preparation of High Loading Pt Nanoparticles on Multiwalled Carbon Nanotubes By Electrodeposition Method Applied for the Anode of Proton Exchange Membrane Fuel Cells
Authors: Hu Sin Yi , Yeh Tsung-Kuang , Wang Mei-Ya 
Published: February 2020

In this study, platinum nanoparticle catalysts grown on carbon nanotubes (CNTs) as the anode of Proton Exchange Membrane Fuel Cell (PEMFC) were prepared by electrodeposition method. In three-electrode electrochemical cell, high electrochemical activity catalysts were obtained by changing the redox potential, time, stirring rate and the concentration of the precursor. After assembling MEA using the high electrochemical activity catalysts as the anode of PEMFC, the single cell test performed high power density by changing hot pressing temperature and time.
Carbon nanotubes by chemical vapor deposition (CVD) were directly grown on the carbon cloth to increase the surface area where the catalysts were deposited. And then, the catalysts were deposited on CNT by the electrochemical method, and finally did test and analyzed. The electrochemical characterizations were obtained by cyclic voltammetry (CV) in argon saturated 0.5M H2SO4, 0.5M H2SO4 + 1M CH3OH solution, respectively. The morphology of Pt/CNT/Carbon Cloth was observed by scanning electron microscope (SEM). The Pt loading was obtained by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the pulsed electrodeposition provided uniform distribution of catalysts ,and the peak power density of homemade Pt/CNT/CC as the anode of PEMFC increased by about 300 mW/cm2 compared to commercial Pt/CB/CC under the same conditions because of carbon nanotubes offering high surface area and having excellent electron conductivity.
Electrocatalytic Activity of Graphene Oxide: Mediating Electron Transfer Between Two Redox Couples
Authors: Kamat Prashant V , Bridewell Victoria 
Published: February 2020

Graphene based materials have been extensively employed to improve the performance of electrochemical storage devices as well as solar cells. Graphene oxide has also been extensively used to improve the performance of electrocatalysts in fuel cells and sensing devices. We have now probed the electron storage and electron shuttling property of graphene oxide by anchoring two redox couples (methyl viologen and ferrocene). During the cathodic scan, we see a quasi-reversible reduction of MV2+ indicating the loss of electrons in charging of reduced graphene oxide. The electrons stored in reduced graphene oxide are then utilized to regenerate ferrocene during the anodic scan. The property of reduced graphene oxide film to store and shuttle electrons shows its ability to act as an electrocatalyst.
(Invited) A Carbon-Carbon Hybrid Immobilizing Carbon Nanodots and Carbon Nanotubes
Authors: Gudi Dirk M. 
Published: February 2020

The thrust of this work is to integrate small and uniformly sized carbon nanodots (CND) with single-walled carbon nanotubes of different diameters as electron acceptors and electron donors, respectively, and to test their synergetic interactions in terms of optoelectronic devices. CNDs were prepared by pressure-controlled microwave decomposition of citric acid and urea. CNDs were immobilized on single-walled carbon nanotubes by wrapping the latter with poly(4-vinylbenzyl trimethylamine) (PVBTA), which features positively charged ammonium groups in the backbone. Negatively charged surface groups on the CNDs lead to attractive electrostatic interactions. Ground state interactions between CNDs and SWCNTs were confirmed by a full-fledged photophysical investigation based on steady-state and time-resolved techniques. As a complement charge injection into the SWCNTs upon photoexcitation was investigated by ultra-short time-resolved spectroscopy.
(Invited) Completely Organic Carbon Nanostructured Thermoelectric Thin Films with Power Factors Exceeding Bismuth Telluride
Authors: Grunlan Jaime , Yu Choongho , Cho Chungyeon , Moriarty Gregory 
Published: February 2020

Low electrical conductivity (s) and thermopower (S) have long excluded polymers from thermoelectric applications. Adding carbon nanotubes produces polymer nanocomposites that exhibit thermoelectric behavior (i.e., generate electricity via a thermal gradient). These nanocomposites exhibit electrical conductivity as high as 200,000 S/m, with a reasonable S (35 – 70 mV/K).1,2 This high electrical conductivity is paired with low thermal conductivity (k ~ 0.3 W m-1 K-1). Power factors (PF = S2s) are as high as 500 mW m-1 K-2) for these composites, containing carbon nanotubes stabilized by porphines and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), making them competitive with inorganic semiconductors (e.g., lead telluride) in terms of conversion efficiency. These composites are lightweight and relatively flexible when compared with traditional semiconductor thermoelectrics (e.g., bismuth telluride). Very recent work using layer-by-layer (LbL) assembly will also be described. Sequential layering of PANi, graphene, and double walled carbon nanotubes (DWNT) produces films with increased carrier mobility, originating from strong π-π interactions between PANi and DWNT and the higher electrical conductivity of graphene. In this investigation of the thermoelectric behavior of an LbL-assembled film, the resulting multilayer thin films exhibit a remarkable power factor (1825 mW m-1 K-2) that exceeds lead telluride and is more than half the value of bulk bismuth telluride.3 Additionally, these water-based systems can be applied like ink or paint, which should further improve their usefulness in harnessing waste heat from a variety of sources (e.g., exhaust manifolds or the human body through clothing). For more information about the Polymer Nanocomposites Lab visit: http://nanocomposites.tamu.edu.

References

1. Moriarty, G. P.; Briggs, K.; Stevens, B.; Yu, C.; Grunlan J. C. Energy Technology
2013, 1, 265-272.
2. Kim, D.; Kim, Y. S.; Choi, K.; Grunlan J. C.; Yu, C. ACS Nano
2010, 4, 513-523.
3. Cho, C.; Stevens, B.; Hsu, J.-H.; Bureau, R.; Hagen, D. A.; Regev, O.; Yu, C.; Grunlan J. C. Advanced Materials
2015, 27, 2996-3001.
Preparation of Graphene/N-Doped Carbon Nanowire Composites for an Effective Electrocatalyst for the Oxygen Reduction Reaction
Authors: Kadumudi Firoz Babu , Choi Won Mook 
Published: February 2020

Platinum (Pt) and its alloys have long been recognized as the best electrocatalyst for ORR in fuel cells. However, high cost due to the scarcity of Pt and its insufficient durability limited the mass production and commercialization of electrocatalysts.Thus, doped carbon materials with various heteroatoms, such as sulfur (S), nitrogen (N), boron (B), and phosphorous (P), has attracted intense attention due to its reportedly high catalytic activity, high long-term durability and tolerance to poisoning as a metal-free ORR electrocatalyst. In this work, we report the facile preparation of graphene decorated with N-doped carbon nanowires for an efficient ORR electrocatalyst. The proposed method here involves the formation of polypyrrole (PPy) nanowires decorated on reduced graphene oxide (rGO-PPy) by in situ polymerization of pyrrole monomer in the presence of rGO. Subsequently, the synthesized rGO-PPy is annealed at 800 oC in an argon atmosphere to afford the N-doped carbon nanowires decorated on rGO (rGO-CN) by the carbonization of PPy nanowires. The prepared rGO-CN exhibits the high nitrogen content and a unique nanostructure afforded by the integration of carbon nanowires and graphene sheets, which facilitate the efficient adsorption of oxygen molecules for improved electron transfer efficiency and increased electrocatalytic activity for ORR. The morphology of rGO-CN is confirmed by TEM analysis and the chemical composition and interaction of the prepared samples are analyzed by XPS and FT-IR analysis. The electrocatalytic activity of rGO-CN toward ORR is also evaluated by the cyclic voltammetry. It is found that the rGO-CN electrode shows superior electrocatalytic performance toward ORR, compared to rGO and rGO-PPy, which demonstrates the promising potential of rGO-CN as a carbon-based, metal-free electrocatalyst for enhancing the electrocatalytic property towards ORR.
Three-Dimensional Porous Carbon Materials with High Surface Area for Electrochemical Energy Storage
Authors: Han Jae Hee , Kim Tae-Ho , Kim Byoung Gak , Hong Young Taik 
Published: February 2020

Supercapacitors are widely recognized as an important class of energy storage devices because they can provide a high specific power and long cycle life. Electrical double-layer capacitors (EDLCs) store charge and release electric energy through the transfer of ions to and from the electrode/electrolyte interface without a Faradaic reaction. Therefore, the amount of energy stored by EDLCs is dependent on the surface area of the electrodes available for electrolyte ion access. However, for the use of the commercial carbon materials such as activated carbon and CNT etc., a poor energy density is observed due to the lack of porous structure which limits the active area for charge storage. Thus, great efforts have been focused on preparation of 3D-porous structure carbons for EDLCs to improve upon these factors.
In this work, a new type of advanced 3D macroporous carbon material derived from PIM-1 with a high surface area and electrical conductivity is proposed and anticipated for energy storage applications. PIM-1 (polymer of intrinsic microporosity) is a polymer with a large fractional free-volume with a high surface area of 760 m2/g and chosen as precursor material for carbonization. 3D macroporous PIM-1 films (NPIMs) with continuously interconnected structure were fabricated by applying the nonsolvent-induced phase inversion method. Finally the carbonized NPIMs (cNPIMs) were obtained through direct high temperature pyrolysis of NPIMs without any external activation agent. The cNPIMs presented a very large surface area (2101.1 m2/g) with narrow micropore size distribution (0.75 nm) as shown in Fig. 1. The SEM analysis revealed that cNPIMs also have a unique 3D macroporous structure having both dense skin layer and gradient pore structure, which is expected to grant a smooth and easy ion transfer capability as an electrode material. Consequently, the cNPIM exhibits a high capacitance (405.8 F/g) and long-term stability in aqueous electrolyte. We believe that our approach can provide a variety of new 3D macroporous carbon materials for the application in a electrochemical energy storage.

Figure 1
Well-Defined Water-Soluble C60-PVP Conjugate
Authors: Tiu Elisha Gabrielle V. , Aroua Safwan , Yamakoshi Yoko 
Published: February 2020

Based on their high photosensitivity, the potential medical application of fullerenes (C60 and C70) such as photodynamic therapy agents has been discussed for decades. Due to their high hydrophobicity, it is necessary to find a good method to solubilize fullerenes in water or water-miscible solvents for such application. We have been using a biocompatible and water-soluble polymer, poly(vinylpyrrolidone) (PVP) to prepare water-soluble C60/ or C70/PVP complex1 and C60- or C70-PVP conjugates2. 3 with efficient reactive oxygen species (ROSs) generation under visible light.4,5 However, in the clinical use, well-defined compounds with narrower molecular weight distribution are favored.
In this study, we synthesized a RAFT reagent 1 for the preparation of well-defined PVP. The terminal moiety was converted to an amine 2 to connect to a C60 acid anhydride derivative 3 which was obtained through a Prato reaction.6 Obtained C60-PVP conjugate had a narrower molecular distribution, high water-solubility and photoinduced ROS generation.7

(1) Yamakoshi, Y.; Yagami, T.; Fukuhara, K.; Sueyoshi, S.; Miyata, N. J. Chem. Soc., Chem. Commun. 1994, 517. (2) Iwamoto, Y.; Yamakoshi, Y. Chem. Commun. 2006, 4805. (3) Oriana, S.; Aroua, S.; Söllner, J. O. B.; Ma, X.; Iwamoto, Y.; Yamakoshi, Y. Chem. Comm. 2013, 49, 9302. (4) Yamakoshi, Y.; Sueyoshi, S.; Fukuhara, K.; Miyata, N. J. Am. Chem. Soc. 1998, 120, 12367. (5) Yamakoshi, Y.; Umezawa, N.; Ryu, A.; Arakane, K.; Miyata, N.; Goda, Y.; Masumizu, T.; Nagano, T. J. Am. Chem. Soc. 2003, 125, 12803. (6) Aroua, S.; Schweizer, W. B.; Yamakoshi, Y. Org. Lett. 2014, 16, 1688. (7) Aroua, S.; Tiu, E. G. V.; Ayer, M.; Ishikawa, T.; Yamakoshi, Y. Polymer Chem. 2015, 6, 2616.

Figure 1
(Invited) Application of Aqueous Two-Phase Partitioning Towards Total Structure Control of Single-Wall Carbon Nanotube Dispersed Populations
Authors: Fagan Jeffrey A. 
Published: February 2020

Scaled separation of single-wall carbon nanotube (SWCNT) populations with completely specified physical structures is a primary milestone necessary for enabling SWCNT-based technologies. Aqueous two-phase extraction (ATPE), in which the spontaneous phase separation of an aqueous polymer mixture is utilized to spatially separate solutes on the basis of their chemical potential difference for the two phases, is a promising technology for achieving this milestone. By implementing multistage iterative separations using surfactant composition gradients, either stepwise or through an automated process, many individual species of SWCNT have been isolated, with isolation for some species to the level of specific left, or right,-handed enantiomer. Results on the improved processing methodologies, including on separation of metallic SWCNT species, will be addressed. Additionally, combination of ATPE with separately developed methods for length separation and endohedral volume specification will demonstrate the progress towards the total structure control goal.
(Invited) A Carbon Nanotube Based Single Photon Source
Authors: Jeantet Adrien , Chassagneux Yannick , Lauret Jean-Sébastien , Reichel Jakob , Voisin Christophe 
Published: February 2020

Carbon nanotubes have strong assets for future integrated single-photon sources since their working wavelength can easily be tuned to the telecom C band by choosing an appropriate diameter [1]. In addition, they show a pronounced antibunching both at low and room temperature[2,3]. Nevertheless, the practical implementation of such a single-photon source requires to embed the nanotube into a micro-cavity in order to funnel the emitted photons into a specific mode (and possibly to an optical fiber) and in order to beat the non-radiative recombination by means of Purcell brightening. In order to tackle the stringent spatial and spectral matching conditions, we developed a flexible micro-cavity design where the concave mirror is micro-engineered at the apex of a single mode optical fiber [4] that can be scanned at the surface of the back mirror where nanotubes has been deposited.
By doing so, we are able to observe, both by means of photon counting and time-resolved measurements a Purcell effect of the order of 6, which allows us to funnel 90% of the photons into the mode [5]. In addition, by exploiting the cavity feeding effect on the phonon side-bands, we are able to tune the source over a 5 THz spectral window while keeping a high spectral purity (80 GHz) and an anti-bunching rate better than 0.01.
[1] V. Ardizzone et al. Phys. Rev. B 91, 121410 (R) (2015)
[2] Hogele et al. Phys. Rev. Lett. 100, 217401 (2008)
[3] Ma et al. Nature nano. 10, 671 (2015)
[4] Hunger et al. N. J. Phys 12, 065038 (2010)
[5] Jeantet et al., arXiv1508:06297 (2015)
(Invited) Single Carbon Nanotube Tracking Reveal Nanoscale Dimensions of Living Tissue Structuration
Authors: Cognet Laurent 
Published: February 2020

The optical microscopy of single molecules has recently been beneficial for many applications, in particular in biology. It allows a sub-wavelength localization of an isolated nano-object and a subtle probing of its spatio temporal nano-environment on cells [1].
For many bio-applications, near infrared nanoprobes and/or more photostable nanoprobes than conventional fluorescent molecules or quantum dots are desirable. In this context, the use of single walled carbon nanotube tubes (SWCNTs) is expected to be favorable. A prerequisite is however to understand and tune their physical properties/morphologies for applications in bio-environments as well as to optimize optical schemes to detect them in complex environments depending on nanotube lengths and foreseen applications [2]. Here we show that by tracking individual SWCNT for minutes, structural information of the living tissues are revealed at the nanoscale. These results, which could not be obtained by other approaches, are obtained by analysis of the structure-dependent diffusion properties of the anisotropic SWCNTs combined to super-resolution imaging strategies [3].

References

[1] Godin et al , Biophys. J, (2014).
[2] Gao, et al, Sci. Rep. (2015); Gao, et al, Biomater. Sci. (2016);
[3] Godin et al submitted