bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultra-Thick Electrodes for Li-Ion Battery
Authors: Zolin Lorenzo , Jimenez-Manero Pablo , Gaubicher Joël , Porcher Willy , Lestriez Bernard
Published: February 2020

In order to meet the challenge of a transition from fossil fuels to green energies, the rapid development of technology is crucial. A characteristic of energy produced from renewable sources is to be discontinuous in time (e. g. photovoltaic or wind turbines). So, as a result of the development of this kind of systems, it is really important to establish a reliable electric energy storage grid. Nowadays, advanced devices that convert and store energy are the focus of intensive attentions and lithium-ion batteries hold the promise of effective solution for a clean electric future.

Nevertheless, the needs to improve performances and reduce costs of Li-ion batteries encourage different research strategies. Among them, an increase in the basis weight of the electrodes active material allows to improve the energy density and to reduce the costs associated with the electrochemical inactive materials (current collectors and separator). The maximum loading achievable by the current industrial reference process, the coating, is limited by the migration of the binder during solvent evaporation phase. Thus, an innovative and effective process, the filtration, is here proposed for the production of ultra-thick electrodes (> 20 mAh / cm² or > 50 mg / cm²). In particular, this research is focused on the adaptation of filtration with the aim to obtain Li-ion battery electrodes and on the development of a pseudo 3D current collector. This innovative current collector is suitable for the filtration process, participates in the transversal electrical conductivity and improves the adhesion of the active layer. The active materials used in this research are commercial LiNiMnCo (NMC) for the cathode and graphite for the anode.

The mechanical properties of ultra-thick electrodes are, of course, critical and will be discussed. Moreover, the remarkable mechanical stability along with the improved adhesion of active material layer with the metallic current collector allows electrodes to be pressed and to attain low porosity, resulting in improved energy density and increased electrical conductivity due to a better contact between particles. The electrochemical performances of electrodes based on NMC/graphite and of a full cells composed of these ultra-thick electrodes will be presented.

These ultra-thick electrodes feature a volumetric energy density greater than the state of art Li-ion electrodes, making them particularly suitable for stock energy produced from renewable and natural sources, giving the possibility to increase the capacity of future electricity grid.

Fig. 1: Ambient temperature galvanostatic cycling behavior of a NMC/graphite ultra-thick cell at different C-rate. Inset shows typical potential vs. specific capacity profile.

Figure 1
New Generation Hybrid Energy Storage Device Based on Nickel Manganese Cobalt Oxide and Activated Carbon Cathode
Authors: Hagen Mark Andrew , Cao Wanjun , Adams Daniel Lawrence , Yturriaga Steven , Zheng Jim P
Published: February 2020

New generation hybrid energy storage devices were created using the battery material Nickel Manganese Cobalt Oxide in combination with Activated Carbon for the cathode. Initial tests were performed on a composite cathode comprised of 25 percent Nickel Manganese Cobalt Oxide and 75 percent Activated Carbon. A comparison of the hybrid composite cathode to traditional commercial cell yielded a specific energy increase of 50 percent from the hybridization of the electrode. The hybrid energy storage device’s capacity was nearly 33 percent higher at low current of 0.08 Amps and was 89 percent of traditional cell at a current of 4.0 Amps. The reduction in max. specific power was found to be approximately 32 percent. Over a current range of 0.08 Amps to 4.0 Amps it can be observed the additional capacity contributed by the Nickel Manganese Cobalt Oxide was no longer seen above 1.0 Amps. Initial cycle life findings indicate at higher currents the cell has the stability traditionally seen with activated carbon electrodes.

Figure 1
Micro-Macroscopic Modeling of a Lithium-Ion Cell By Considering Grain Boundaries of Active Materials
Authors: Hoffmann John Alexander , Park Jonghyun
Published: February 2020

Many important properties of electrode materials are profoundly sensitive to deviations from the crystalline perfection. Among them are grain boundaries that play an important role on battery performance by changing the ions distribution inside particles and corresponding stress level change. This paper explores the mechanical and microstructural aspect of battery behavior by developing a cell-level model that incorporates grain boundary diffusion in the electrode particles for the anode and cathode electrodes. The developed model is compared against the grainless model at various operating conditions to understand how grain boundaries influence capacity and stress generation. The results show an appreciable effect of grain boundary diffusion on the voltage profile for the cell for the parameters tested and, overall, a significant reduction in the maximum induced stress experienced in the cell. Stress behavior between the anode and cathode differ significantly, and show that the effective diffusivity of a particle might matter much more significantly than its location in the cell.
First-Principles Modeling of the Initial Stages of Ethylene Carbonate Decomposition on LixCoO2 (110) Surfaces
Authors: Qin Xueping , Shao Minhua
Published: February 2020

Lithium ion batteries (LIBs) have been widely used in electric vehicles. At the same time, high capacities of batteries are required desperately, which could be realized by increasing the operational voltage of LIBs. However, side reactions occur under these high voltages at the cathode-electrolyte interface because of the instability of electrolyte components1-3, leading to electrode degradation, capacity fade and poor cycling stability of batteries and also some safety issues. Therefore, it is meaningful to understand the decomposition mechanism of organic solvents in LIBs, which could pave the way for electrode material design and battery design.

In this study, first-principles calculations were performed to investigate the initial stage of ethylene carbonate (EC) decomposition on the stable (110)4 surface of LixCoO2 (LCO, x=0.67, 1). For the possible initial decomposition reactions of EC on cathode surfaces, H-abstraction reaction and ring opening reaction have been proposed5, 6 and investigated on LixMnO2 surfaces7, 8. For the adsorption models of EC on LCO (110) slab, parallel (Fig. 1a) and Oc-upward (Fig. 1b) configurations were adopted, and the corresponding reaction barriers of possible reactions in two configurations were calculated by density functional theory (DFT) calculations. Climbing image nudged elastic band (CINEB) method was used to search the transition state (TS) and minimum energy path (MEP) of certain reactions.

Based on the calculation results, H-abstraction reaction (ΔEbarrier = 0.96 eV) is prone to occurring in a parallel configuration on LCO (110), while ring opening reaction (ΔEbarrier = 0.89 eV) is favored in Oc-upward configuration. These predicted EC decomposition fragments may not be the final products of side reactions, which could also react with other adsorbed fragments, leading to the SEI formation. The following reactions are considered and discussed in the presentation.

References

1. Aurbach, D.; Gofer, Y.; Langzam, J. Journal of the Electrochemical Society
1989,136, (11), 3198-3205.

2. Etacheri, V.; Marom, R.; Elazari, R.; Salitra, G.; Aurbach, D. Energy & Environmental Science
2011,4, (9), 3243-3262.

3. Peled, E.; Gabano, J. AP
1983.

4. Daheron, L.; Martinez, H.; Dedryvere, R.; Baraille, I.; Ménétrier, M.; Denage, C.; Delmas, C.; Gonbeau, D. The Journal of Physical Chemistry C
2009,113, (14), 5843-5852.

5. Borodin, O.; Olguin, M.; Spear, C. E.; Leiter, K. W.; Knap, J. Nanotechnology
2015,26, (35), 354003.

6. Gauthier, M.; Carney, T. J.; Grimaud, A.; Giordano, L.; Pour, N.; Chang, H.-H.; Fenning, D. P.; Lux, S. F.; Paschos, O.; Bauer, C. The journal of physical chemistry letters
2015,6, (22), 4653-4672.

7. Leung, K. The Journal of Physical Chemistry C
2012,116, (18), 9852-9861.

8. Kumar, N.; Leung, K.; Siegel, D. J. Journal of The Electrochemical Society
2014,161, (8), E3059-E3065.

Fig. 1. Adsorption models of EC on LCO (110) in a parallel configuration (a) and Oc-upward configuration (b).

Figure 1
Silver Oxide-Cobalt Phosphate Nanoparticle/ Nanoflake As a High Performance Supercapattery Electrode
Authors: Shao Han , Narayanasamy Padmanathan , McNulty David , O'Dwyer Colm , Razeeb Kafil M.
Published: February 2020

Artificial cardiac pacemaker as an electronic device, can deliver the electrical impulses to regulate the heartbeats during emergency. In order to prevent the unnecessary injury caused by battery-replacement surgery, there is an urgent need to have a better energy storage device that could store enough energy with an excellent lifetime for 20 years. Supercapattery is a hybrid energy storage device, which combines the best of both battery and supercapacitor worlds and should be able to store enough energy like a battery with cyclability and specific power similar to a supercapacitor. Thereby, we are fabricating novel nanomaterials based electrodes for the development of these hybrid energy storage devices.1-2

In this work, a heterostructure of silver oxide - cobalt phosphate nanoparticle/ nanoflake was synthesized on nickel foam (NF) via simple hydrothermal method. The electrode was analyzed by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscope (TEM) to study the composition, structure and morphology of the heterostructure. The silver oxide nanoparticle enhanced the surface area of the electrode and improved electrochemical performance. The heterostructured electrode showed a wide potential window of 0.75 V in 3.0 M KOH solution and delivered a maximum specific capacity of 282.4 mAh g-1, which is equivalent to 1355.3 F g-1with no decay after 1,000 charge-discharge cycles. The performance of this heterostructure will be reported as a positive electrode in a complete supercapattery device configuration.

Acknowledgment

The authors acknowledge financial support from EU FP7 project MANpower (Contract 604360) to carry out this work.

Corresponding author's email address: kafil.mahmood@tyndall.ie

Reference

[1] Shao H.; Padmanathan, N.; McNulty, D.; O'Dwyer, C.; Razeeb, K. M., Supercapattery based on binder-free Co3(PO4)2·8H2O multilayer nano/ microflakes on nickel foam. ACS applied materials & interfaces
2016, 8, pp. 28592-28598.

[2] Padmanathan, N.; Shao, H.; McNulty, D.; O'Dwyer, C.; Razeeb, K. M., Hierarchical NiO–In2O3 microflower (3D)/ nanorod (1D) hetero-architecture as a supercapattery electrode with excellent cyclic stability. J. Mater. Chem. A
2016,
4(13), pp. 4820-4830.

Figure 1. SEM image of silver oxide-cobalt phosphate electrode.

Figure 1
(Invited) Building Supercapacitors with Earth-Abundant Materials
Authors: Sarkar Debasish , D. Sarma D. , Shukla Ashok Kumar
Published: February 2020

Hematite (α-Fe2O3) is an environment-friendly and earth-abundant negative electrode material for electrochemical supercapacitors. It has high theoretical specific-capacitance with a suitable operating-potential-window. However, its use as positive electrode material has been limited. In the light of the foregoing, we have investigated the feasibility of using α-Fe2O3 both as positive and negative electrodes to examine its versatility in supercapacitors. On the other hand, MnO2 has been investigated extensively as positive electrode in supercapacitors because of its striking electrochemical activity. But MnO2 exhibits poor electronic conductivity and has low-rate capability. To address this issue, a core-shell nanorod-based positive electrode is designed combining the aforesaid traits of α-Fe2O3 and MnO2. In the core-shell design, MnO2 shell serves as active site for surface or near-surface based fast and reversible faradaic reactions while α-Fe2O3 nanorod core facilitates electron transfer towards current collector. As a consequence of this synergy, α-Fe2O3/MnO2 core-shell nanorod electrode shows improved electrochemical performance in terms of capacitance and rate capability within a potential window of 0-1 V in comparison to individual component materials. Moreover, the assembled asymmetric supercapacitor (ASC) using α-Fe2O3/MnO2 core-shell nanorods and pristine α-Fe2O3 nanorods as respective positive and negative electrodes exhibit a volumetric capacitance of ~ 1.3 F/cm3 at a scan rate of 10 mV/s within a potential window of 0-2 V with nearly 78% capacitance retention at a scan rate of 400 mV/s. Interestingly, the ASC delivers a maximum energy density of ~ 0.46 mWh/cm3 at a current density of 0.5 mA/cm2; the power density of the ASC being 550 mW/cm3 at a current density of 5 mA/cm2 while energy density reaches ~ 0.35 mWh/cm3.
Polydopamine: A Promising Organic Cathode for Rechargeable Batteries
Authors: Liu Tianyuan , Lee Byeongyong , Kim Ki Chul , Jang Seung Soon , Lee Seung Woo
Published: February 2020

Organic electrodes have been promising candidate for large-scale electrical energy storage applications thanks to several advantages, such as low cost, high theoretical capacity, and chemical diversities. However, their high solubility in organic electrolytes and poor electrical conductivity have limited their cycling stability as well as rate capability. A promising strategy to address these issues is to polymerize organic molecules onto conductive carbon substrates.1 In composite structure, the covalent bonds between the monomers can prevent the dissolution of molecules, while conductive carbon can support the fast redox reactions in the polymer.1 Tremendous efforts have been devoted in developing nanocomposite by polymerizing carbonyl compounds on various nanocarbons such as graphene or carbon nanotubes.1 The electrochemical performance of the composites strongly dependents on their microstructures, which indicates that the interface between the redox-active polymer and nanocarbon support should be optimized for maximizing the electrochemical performance of the composite electrodes.1

In our recent study, we investigated the electrochemical properties of polydopamine by both computational and experimental methods. The density functional theory (DFT) calculations show that polydopamine can interact with both electrolyte ions (cations and anions) at high voltage region of 2.5~4.1 V vs. Li, and the interactions are also confirmed by cyclic voltammetry measurements.1 Comparing with the complicated polymerization process for most polymer cathode materials, dopamine can be spontaneously polymerized in weak alkaline solutions.1 We fabricate the free-standing and flexible hybrid electrodes by spontaneously coating polydopamine onto few-walled carbon nanotubes.1 The hybrid electrodes delivered a gravimetric capacity of ~133 mAh/g in Li-cells utilizing double layer capacitance from FWNTs and multiple redox-reactions from polydopamine.1 In addition, for further improving the performance of the composite electrodes, we utilized reduced graphene oxide as a redox-active and conductive substrate for the growth of polydopamine. During the hydrothermal treatment, dopamine can reduce and functionalize the graphene oxide simultaneously, which results in a 3D structured functionalized graphene hydrogel. The functionalized graphene shows a significantly enhanced capacity up to 200 mAh/g.

Reference:

1. T. Liu, K. C. Kim, B. Lee, Z. Chen, S. Noda, S. S. Jang and S. W. Lee, Energy & Environmental Science, 2016. DOI: 10.1039/C6EE02641A
Electrochemical Performance of Lithium-Ion Capacitors Evaluated Under Thermal and High Voltage Stress with Various Electrolytes
Authors: Boltersdorf Jonathan , Delp Samuel A. , Zheng Jim P , Jow T Richard , Read Jeffrey A.
Published: February 2020

Research investigations into lithium-ion capacitors (LICs) for high power, moderate energy density Army applications have been evaluated under room temperature, high temperature, and high voltage conditions. The LICs were assembled as three-layered cells with an asymmetric configuration employing Faradaic pre-lithiated hard carbon anodes and non-Faradaic anion adsorption−desorption activated carbon (AC) cathodes. The LIC three-layered cells were tested for their rate capability at 1C to 10C discharge rates over the potential range of 2.2-3.8 V using various electrolytes and additives. The presence of electrolyte additives were found to be essential to the improved capacity performance and contribute to the prolonged cell cycling stability at room temperature, at high temperature, and at higher cut-off potentials.
Nanostructure Silicon-Based Hierarchical Architectures for High-Performance Lithium-Ion Battery Anode
Authors: Ambrosio Zanin Maria Helena , Li Xuemin , Bender Guido , Son Seoung-Bum , Ban Chunmei
Published: February 2020

Silicon (Si) has the highest specific capacity (4200 mAhg-1) and volumetric capacity (9786 mAh cm-3) among the material candidates, which makes it the most promising material for the Lithium Ion Battery (LIB). However, the drastic volume fluctuation (~400%) during the lithiation/delithiation process reduces the battery cyclability and affects the battery reversibility. To overcome these limitations, different architectures have been developed for incorporating Si to accommodate the volumetric changes within the conductive matrix.

The combination of electrospinning and electrospray processes has been used to fabricate three different hierarchical network architectures based on nanoscale Si and Polyacrylonitrile (PAN). Among these hierarchical architectures, the core-shell Si/PAN structure and the Si/PAN multilayer structure have significantly improved the cycling performance with high capacity and good capacity retention. Cyclization has also been performed to form the hierarchical conductive framework, which provides a continuous electron transport network and high porosity to address the volume expansion during electrochemical reactions. By integrating electrospray process in the synthesis process, a greatly improved capacity is achieved with a high reversible area capacity over 2mAh/cm2. This work will present the results of our systematic investigation on structure-property relationships in the Si/PAN hierarchical architectures.
The Statistics of Battery Failure
Authors: Harris David J , Li Chen , Harris Stephen J
Published: February 2020

There is a large literature on state of health (SOH) analysis that aims to be used for predicting the remaining useful life (RUL) of in-service commercial Li ion batteries. These studies generally rely on libraries of off-line experiments to correlate battery operating parameters to RUL. However, the accuracy of these predictions must ultimately be limited by the statistical variation of RUL among nominally identical cells. There are relatively few publications that assess capacity decline in enough commercial cells to adequately quantify this variation (e.g. >10 cells), but those that do show a cell-to-cell variability in capacity fade that is surprisingly wide. Furthermore, capacity vs cycle number curves generally cross each other many times in large samples, a challenge to RUL predictions. In this work we analyze the capacity fade statistics for 24 nominally identical commercial pouch cells, finding a wide cell-to-cell variability that is qualitatively similar to that seen in other work. Our data indicate that RUL predictions based on remaining capacity can be reasonably accurate only after a large number of failures have already been observed. Analysis of our failure data with normal and with 2- and 3-parameter Weibull probability density functions provide uniformly good fits using a variety of definitions of failure, although we argue against using a 3-parameter Weibull function for our data. We see preliminary indications in our data that the pdf fitting parameters asymptotically approach constant values. We suggest a strategy whereby testing continues until a predesignated confidence level for failure probability has been achieved, rather than using a predesignated number of cycles (Type I censoring) or a predesignated number of failures (Type II censoring). An increased emphasis on making batteries whose lifetimes are more reproducible could lead to improvements in battery cost and safety.

Figure 1
(Invited) Highly Ordered Endohedral Fullerene Derivatives for an Ensemble of Controllable Qubits
Authors: Porfyrakis Kyriakos
Published: February 2020

Paramagnetic endohedral fullerenes hold promise for quantum information processing. In the case of endohedral nitrogen fullerenes such as N@C60 and N@C70, the nitrogen atom is almost completely isolated from the fullerene cage. This results in very long electron spin phase coherence times. The chemistry of endohedral nitrogen fullerenes has developed to a degree where it can be used to create functionalized systems with high aspect ratios that are prone to high alignment. In this talk, I will present our recent results for several N@C60 and N@C70 derivatives that we have aligned in liquid crystals. Within the liquid crystal matrix, we have achieved an order parameter factor Ozz
of 0.61. This is a significant improvement on the best result that has been previously reported for endohedral fullerene derivatives. More importantly, this allows us to manipulate the intrinsic zero-field splitting (ZFS) of the spin resonance signal. By in-situ rotating frozen endohedral fullerenes inside the magnetic field of the ESR spectrometer, we deliberately changed the orientation distribution of the molecules and tuned the splitting energy of ZFS. We achieved remarkable agreement between experimental values and simulation data. This work can be expanded to control of dipolar coupling for a two-qubit gate. Hence it is quite pertinent to research on potential applications of endohedral fullerenes.
(Invited) Uranium Endohedrals: New Frontiers in Fullerene Chemistry
Authors: Murillo Jesse , Cai Wenting , Zhang Xingxing , Najera Daniel , Romero Elkin L. , Suarez Catalina , Metta-Magana Alejandro J. , Chen Ning , Echegoyen Luis
Published: February 2020

Uranium endohedrals are an emerging class of fullerenes that may hold extraordinary properties and exhibit remarkable chemical features.[i] [ii] Our group been on the forefront of research in this area and have made progress in the synthesis of these novel compounds. By optimizing reactive conditions, we have seen a markedly improved selective production of uranium endohedrals using the
Kraetschmer
– Huffmann arc discharge process. Here we report the successful synthesis of several families of uranium endohedrals characterized by mass spectrometry which include clusters of the type U2X (X= C, N, O). Mono-metallic uranium endohedrals, with general formula U@Cn, have also been synthesis and characterized by x-ray crystallography (see Fig 1.) Electrochemical studies of some of these new compounds have been conducted and are reported herein. These findings realize a two-decade long effort in the scientific community for physical studies of such endohedral fullerenes. [iii] [iv] [v]

[i] Foroutan-Nejad C, Vícha J, Marek R, Patzschke M, Straka M, Phys Chem Chem Phys., 2015, 17(37)

[ii] Dunk, Paul W., Kaiser, Nathan K., Mulet-Gas, Marc; Rodriguez-Fortea, Antonio, Poblet, Josep M., Shinohara, Hisanori, Hendrickson, Christopher L., Marshall, Alan G., Kroto, Harold W., Journal of the American Chemical Society, 2012, 134(22), 9380-9389

[iii] Guo, T., Diener, M. D., Chai, Y., Alford, M. J., Haufler, R. E., McClure,S. M., Ohno, T., Weaver, J. H., Scuseria, G. E., Smalley, R. E., Science, 1992,257, 1661.

[iv] Diener, M. D., Smith, C. A., Veirs, D. K., Chem. Mater., 1997, 9, 1773

[v]Kazuhiko Akiyama , Yuliang Zhao , Keisuke Sueki ,* Kazuaki Tsukada ,† Hiromitsu Haba ,† Yuichirou Nagame ,† Takeshi Kodama , Shinzou Suzuki , Tsutomu Ohtsuki ,‡ Masahiko Sakaguchi , Koichi Kikuchi , Motomi Katada , and Hiromichi Nakahara, J. Am. Chem. Soc., 2001, 123 (1), pp 181–182

Figure 1
(Invited) Water and Water-Dimer Encapsulations into C70 and C84
Authors: Uhlik Filip , Slanina Zdenek , Akasaka Takeshi , Lu Xing
Published: February 2020

Water and water-dimer encapsulations into D5h-C70 and D2(22)-C84 & D2d(23)-C84 fullerenes are evaluated. The water-dimer equilibrium populations are computed using the potential-energy change from the ab initio G3 theory and anharmonic partition functions from the MP2/AUG-cc-pVQZ approach. The encapsulation energetics is treated at the M06-2X/6-31++G** level and it is found, for example, that the water-dimer storage in C84 is attractive, yielding an energy gain of more than 10kcal/mol. This substantial encapsulation energy together with the computed temperature increase of the water-dimer population in the saturated steam suggest that the (H2O)2@Cn endohedrals could also be produced in a

high-temperature/high-pressure approach similarly to encapsulation of rare gases in fullerenes.
(Invited) Rotaxanes and SWNTs Tie the Knot
Authors: Perez Emilio M
Published: February 2020

Here, we present a strategy for the synthesis of rotaxane-type derivatives of carbon nanotubes, the first example of mechanically interlocked derivatives of SWNTs (MINTs).1 In the key rotaxane-forming step, we employed macrocycle precursors equipped with two recognition units and terminated with bisalkenes that were closed around the nanotubes through ring-closing metathesis (RCM). The mechanically interlocked nature of the derivatives is probed by analytical, spectroscopic, and microscopic techniques, as well as by appropriate control experiments. Remarkably, bulk reaction data confirm the interlocked nature of MINTs.

We will also show that the effect of the mechanical bond on the properties of SWNTs is unique, and clearly different from the noninterlocked, supramolecular compounds.3

References:

(1) a) de Juan, A.; Pérez, E. M. Nanoscale
2013, 5, 7141; b) de Juan, A.; Pouillon, Y.; Ruiz-Gonzalez, L.; Torres-Pardo, A.; Casado, S.; Martin, N.; Rubio, A.; Pérez, E. M. Angew. Chem., Int. Ed.
2014, 53, 5394; c) López-Moreno, A.; Pérez, E. M. Chem. Commun.
2015, 51, 5421; Leret, S.; Pouillon, Y.; Casado, S.; Navio, C.; Rubio, A.; Perez, E. M. Chem. Sci.
2017, DOI: 10.1039/c6sc03894h.

(2) a) de Juan, A.; Mar Bernal, M.; Perez, E. M. ChemPlusChem
2015, 80, 1153; b) de Juan, A.; Lopez-Moreno, A.; Calbo, J.; Orti, E.; Perez, E. M. Chem. Sci.
2015, 6, 7008.

(3) a) Martínez-Periñán, E.; de Juan, A.; Pouillon, Y.; Schierl, C.; Strauss, V.; Martín, N.; Rubio, A.; Guldi, D M.; Lorenzo, E.; Pérez, E.M. Nanoscale, 2016, 8, 9254; b) Lopez-Moreno, A.; Nieto-Ortega, B.; Moffa, M.; de Juan, A.; Bernal, M. M.; Fernandez-Blazquez, J. P.; Vilatela, J. J.; Pisignano, D.; Pérez, E. M. ACS Nano
2016, 10, 8012.
(Invited) Perixanthenoxanthene (PXX) As Molecular Dye for Fullerene-Based Reaction Centers
Authors: Bonifazi Davide
Published: February 2020

Based on the unique electronic and structural properties, carbon nanostructures and are promising candidates for the constructions of advanced multidimensional organic architectures. Therefore a detailed understanding of the chemical and physical properties of these all-carbon structures is crucial for the further and targeted development of advanced materials. The main purpose of our work is to design and investigate new classes of carbon nanostructures with defined structural, physical, and chemical properties which are suitable as functional materials, e.g. in the field of organic conductors, photonic applications, and biological applications.

Herein we report the recent progresses achieved in our laboratory on the synthesis, characterization, and physical studies of new classes of [60]fullerene-based reaction centers equipped with new chromophoric antennas.
(Invited) High Temperature and High Magnetic Field Superconductivity in Fullerides
Authors: Prassides Kosmas
Published: February 2020

Molecular solids whose cooperative electronic properties are based purely on π-electrons from carbon atoms offer a fertile ground in the search for exotic states of matter, including unconventional superconductivity. C60-based solids with stoichiometry A3C60 (A = alkali metal) are archetypal examples of molecular superconductors with the highest superconducting transition temperatures (T
c = 38 K) among all molecular systems known [1]. More recently, we have shown that they also display the highest upper critical magnetic field (H
c2 > 90 Tesla) among all known three-dimensional superconducting solids [2]. The dominance of strong electron correlations in defining their behavior poses significant challenges for understanding the highly robust superconducting response to both temperature and magnetic field in these highly correlated organic metals. Here I will briefly describe this field of fullerene science with emphasis on its current status and future prospects.

References

[1] R. H. Zadik et al., Science Advances
1, e1500059 (2015).

[2] Y. Kasahara et al., Nature Communications, in press.
(Invited) Computational Studies on Exohedral Metallofullerenes and Multiadduct C60 Systems
Authors: Rodriguez-Fortea Antonio , Moreno-Vicente Antonio , Azmani Khalid , Poblet Josep M.
Published: February 2020

Computational chemistry has helped so far not only to understand the regioselectivity of a wide variety of chemical functionalizations on C60 and endohedral metallofullerenes (EMFs), but also to disclose in many cases their reaction mechanisms. In this communication we will show the recent progress on our group related to different topics, as (1) the prediction of halogenation and hydrogenation of EMFs confirmed by experiments; and (2) the analysis of stereoselective reactions on C60 hexaadducts, as well as other related systems.
(Invited) Metal-Bonding Electrons inside the Fullerene Cage: Electrochemical, Quantum Chemical and EPR Studies
Authors: Samoylova Nataliya , Stevenson Steven , Liu Fupin , Popov Alexey A.
Published: February 2020

Electronic properties of endohedral metallofullerenes (EMFs) and especially their behavior in the charge transfer processes have been in the focus since the middle of 1990s, when sufficient amounts of EMFs became available.

The Closed carbon shell of EMF represents itself as a suitable environment for stabilization of different exotic metal species, including dimetallic clusters with metal-metal bond.

Here we report the electrochemical properties of M2@C82 clustersfullerenes (2 cage isomers of C82: with C3v and Cs symmetry; M=Lu, Er, Sc) . UV-Vis and NIR absorption spectroscopy data and theoretical calculations expose the unique structure of M2@C82 EMFs with two M2+ions inside the cage, connected with metal-metal bonding (despite the fact that in majority of EMFs lanthanides demonstrate oxidation state 3+).

Electrochemical experiments along with theoretical calculations have proved that metal-metal bonding orbital in EMFs is always one of the frontier orbitals, and its energy to a great extant determines the redox behavior of the molecule. For M2@C82 family metal-metal bonding orbital presents itself as a HOMO. The cyclic voltammetry has revealed the cathodic shift* of the first oxidation potential for Sc2- and Er2-EMFs in comparison with corresponding isomers of Lu2@C82, caused by the significant difference in position of the HOMO.

Monocation of Sc2@C82-C3v, generated by chemical oxidation, has been studied with EPR spectroscopy as well. Due to the spd-character of metal-metal bonding orbital, the spin density at the nuclei is extremely high, that provides the second order effects in line position and variations of the signal line width.
Comparison of Graphene Materials for Supercapacitor Electrodes
Authors: Le Fevre Lewis
Published: February 2020

Research into graphene supercapacitors is currently undergoing a large increase in growth due to its beneficial chemical and mechanical properties. However, reports on ‘graphene’ supercapacitors use graphene materials produced through various methods. Currently, there has been no investigation into the effect the production method has upon the capacitance of the system, meaning direct comparison of the literature is not possible. In this work we compared several ‘types’ of graphene. These include “pure” graphene samples which include liquid phase exfoliated graphene, graphene nanoribbons, anodically exfoliated electrochemically graphene in aqueous system and cathodically exfoliated electrochemically exfoliated graphene in an organic system. Also included were “modified” graphene samples which included graphene oxide and reduced graphene oxide. It was observed that graphene oxide exhibited the highest specific capacitance of 164 F/g (5-10 times higher) , measured at a current density of 0.5 A/g, due to the oxygen containing functional groups giving an additional pseudocapacitance response as well as preventing restacking of the material. The graphene oxide also showed similar or superior cyclability when compared to the other pure and modified graphene materials. However, due to its intrinsically high resistance the addition of a conductive additive is required to achieve high rate capability. The higher capacitance and less energy demanding processing indicate that graphene oxide may be a better choice for high energy supercapacitor applications than “pure” graphene which will be suitable for high power applications.
Enhancing the Electrocatalytic Activity of Graphitic Carbon Nitride Towards Oxygen Reduction Reaction Via Heteroatom Doping: A DFT Approach
Authors: Futalan Wilbert James Claridad , Divinagracia Maricor Fernandez , Serraon Ace Christian , Padama Allan Abraham Bustria , Cervera Rinlee Butch , Ocon Joey Duran
Published: February 2020

With the continued depletion of conventional fuel sources, the search for alternative fuel becomes increasingly important. Low temperature fuel cells such as PEMFCs and AFCs have attracted significant attention as a power generation technology. However, the cost of noble metals—which are important in speeding up the sluggish oxygen reduction reaction—remains an impediment in the commercialization of this technology. Metal-free catalysts are now being seen as possible alternatives to these noble metals. Among these metal-free catalysts is the graphitic carbon nitride. Graphitic carbon nitride, g-C3N4, is a polymeric material consisting of C, N, and some impurity H, connected via tris-triazine-based patterns. Due to its unique electronic structure, g-C3N4 and other graphene analogs have garnered interest in the material science community. While previous studies have been able to show experimentally the activity of g-C3N4 towards ORR, ab initio studies to explain and generalize the findings of the experiments remain scarce. Here we explain from the standpoint of density functional theory (DFT) calculations the effect of heteroatom doping (e.g., phosphorus, boron, sulfur) in further altering the material’s electronic structure in an effort to render g-C3N4 more active towards oxygen reduction reaction. The trends exhibited by graphitic carbon nitrides in our DFT computations indicate that this emerging class of material can pave the way for the rational design of fuel cell catalysts.
(Invited) Eau De Graphene : Additive Free, Single Layer Graphene in Water
Authors: Penicaud Alain
Published: February 2020

Dispersions of single layer graphene in water will be presented. 1-3

Authors: G. Bepete, E. Anglaret, C. Drummond, A. Penicaud

1. Surfactant Free Single Layer Graphene in Water, G. Bepete, E. Anglaret, L. Ortolani, V. Morandi, K. Huang, A. Pénicaud, C. Drummond, Nature Chemistry, 2016, DOI:10.1038/NCHEM.2669

2. Raman Signatures of Single Layer Graphene Dispersed in Degassed Water, ‘‘Eau De Graphene’’, G. Bepete, A. Pénicaud, C. Drummond, E. Anglaret, J. Phys. Chem. C, 2016, DOI: 10.1021/acs.jpcc.6b07288.

3. “Eau de Graphene” from a KC8 Graphite Intercalation Compound prepared by a simple mixing of graphite and molten potassium, G. Bepete, F. Hof, K. Huang, K. Kampioti, E. Anglaret, C. Drummond, A. Pénicaud, Phys. Status Solidi Rapid Res. Lett. DOI 10.1002/pssr2016.00167
Nsaids- Derived Mitochondrial Reactive Oxygen Species Accelerated Cancer Specific Porphyrin Accumulation to Enhance Photodynamic Therapeutic Effect in Gastric Epithelial Cells
Authors: Matsui Hirofumi , Ito Hiromu
Published: February 2020

Photodynamic therapy is useful for the treatment of cancer because it is minimally invasive for patients. Certain porphyrin compounds and their derivatives have been used as the photosensitizer because they accumulate specifically in cancerous tissues. However, the detailed mechanism of this phenomenon has not been clarified. We previously reported that a proton-coupled folate transporter, HCP1, transported porphyrins and that regulation of the protein was associated with cancer-specific reactive oxygen species from mitochondria (mitROS) (Hiyama K et al.
J Porph Phtal. 2013; 17: 36–43). Therefore, over-generation of mitROS could increase HCP1 expression and the effect of photodynamic therapy. We investigated whether pretreatment with indomethacin influenced photodynamic therapy by using a rat normal gastric mucosal cell line, RGM1, its cancer-like mutated cell line, RGK1, and a manganese superoxide dismutase (MnSOD)-overexpressed RGK cell line, RGK-MnSOD. Indomethacin promotes the generation of cellular mitROS by inhibiting the electron transport chain, and MnSOD scavenges the mitROS. We elucidated that indomethacin enhanced cancer-specific mitROS generation and increased HCP1 expression. Furthermore, RGK1 cells showed higher cellular incorporation of hemato-porphyrin and better therapeutic effect with indomethacin treatment whereas RGK-MnSOD cells did not show a difference. Thus, we concluded that indomethacin improved the effect of photodynamic therapy by inducing increased mitROS generation in cancer cells.
Fused-Porphyrin Terbium Complexes: Correlations Between Electronic Structure and Single-Molecule Magnetic Property
Authors: Lee Sunri , Yamashita Ken-ichi , Yamashita Satoshi , Ogawa Kaya , Hirao Yasukazu , Sakata Naoya , Ishikawa Naoto , Ogawa Takuji
Published: February 2020

Since the first discovery of phthalocyanine terbium double-decker complexes (Tb(Pc)2) as organic single-molecule magnets (SMMs) having high blocking temperature in 2004; double-decker complexes of lanthanide ions and tetrapyrrole ligands have attracted much attention.1 Recently, Tb(Pc)2 complexes were applied to spintronic devices due to their excellent properties. We have reported previously that the SMM property of porphyrin terbium double-decker complexes (Tb(Por)2) can be switched ON/OFF by the absence/presence of a proton or a hydrogen. Asymmetrical protonated forms (Tb(PorH)(Por)) do not exhibit SMM property, while symmetrical deprotonated anionic forms (Tb(Por)2
-) show prominent SMM character.2,3 

Herein, we report about fused-porphyrin terbium complexes having two or more terbium ions and several porphyrin cores as ligands. Since these complexes have more than two protons, they have more diversity in electronic structures than single core complexes. We have successfully synthesized fused-porphyrin terbium triple-decker complexes ([Tb2]) in protonated form (diprotonated-[Tb2]), anionic form (dianionic-[Tb2]), and radical form (biradical-[Tb2]). The structural, spectroscopic and magnetic properties of these complexes were evaluated to show unique character of these complexes. The biradical-[Tb2] has extraordinarily small energy gap (~2700 nm). Switching of SMM property by the presence and absence of protons was also confirmed in [Tb2]. The relatively high blocking temperature of dianionic-[Tb2] could be attributed to its highly symmetrical molecular structure. In addition, SMM property of biradical-[Tb2] was almost similar to that of radical-Tb(TPP)2, which will enable highly conductive SMM wire of terbium multiple-decker complex ie. [Tb4], because of the small energy gap.

References

1) Ishikawa, N.; Sugita, M.; Tanaka, T.; Ishikawa, T.; Koshihara, S.; Kaizu, Y. Inorg. Chem. 2004, 43, 5498.

2) Tanaka, D.; Inose, T.; Tanaka, H.; Lee, S.; Ishikawa, N.; Ogawa, T. Chem. Commun. 2012, 48, 7796.

3) Inose, T.; Tanaka, D.; Tanaka, H.; Ivasenko, O.; Nagata, T.; Ohta, Y.; Feyter, S. D.; Ishikawa, N.; Ogawa, T. Chem. Eur. J. 2014, 20, 11362.

Figure 1
Inter-Digitated Photo-Active Strands
Authors: Rein Regis , Solladie Nathalie , Aziat Farid
Published: February 2020

In natural photosynthetic systems, the solar energy is collected by pigment molecules attached to the light harvesting complexes. In these units, the chlorophylls are held in a favored spacing and orientation by fairly short α-helical polypeptides.1 When a photon hits one of the chlorophylls, the absorbed energy spreads extremely rapidly to the others until the reaction center is reached within the cell membrane, where the solar energy is converted into chemical energy used by the cell to grow. In this way, the energy contained in a single photon is conducted in a very short time and with minimal loss of energy from the point where it is absorbed to where it is needed. The extraordinary efficiency of the energy migration over long distances with minimal loss of energy is ascribed to the favored spacing and orientation of the chlorophylls which are held in an appropriate parallel conformation. Beyond the control of the structure of multi-chromophoric arrays, monitoring the spatial orientation of the chromophores in artificial light harvesting devices is a challenge of growing interest. Indeed, multi-porphyrinic arrays attract more and more attention for the elaboration of photonic and electronic wires.2

An octapeptide3 and an hexadecapeptide4 derived from the L-lysine and functionalized with porphyrins have been prepared. Beyond a certain degree of oligomerisation, we observed the development of a secondary structure such as a 310 helix which forces the porphyrins to arrange in a defined spatial arrangement. Due to the overlap of the porphyrins in such a conformation, the chromophores undergo a sufficient electronic coupling to favor a good exciton migration.5

The ability of these peptides to accomodate guests was investigated through ligand binding studies carried out in dichloromethane with DABCO as bidentate base. The complexation of DABCO by these peptides was monitored by UV-visible spectrophotometric titration in CH2Cl2. We showed that the enhanced stability of the complexe octapeptide/DABCO can be ascribed to a pre-organization of the octapeptide forming cavities, and provides convincing evidence that the bidentate base is inserted into the cavities of the octapeptide via host/guest interactions.

Acknowledgements

This work was supported by the CNRS and the French Ministry of Research.

References

W. Kühlbrandt, Nature
1995, 374, 497-498.

a) R. W. Wagner, J. S. Lindsey, J. Seth, V. Palaniappan, D. F. Bocian, J. Am. Chem. Soc.
1996, 118, 3996-3997 and ref. cited therein. b) M. J. Crossley, P. L. Burn, S. J. Langford, J. K Prashar, J. Chem. Soc., Chem. Commun.
1995, 1921-1923. c) A. Osuka, H. Shimidzu, Angew. Chem. Int. Ed. Engl.
1997, 36, 135-137.

N. Solladié, A. Hamel, M. Gross, Tet. Lett.
2000, 41, 6075-6078.

Unpublished results.

a) M. Fujitsuka, M. Hara, S. Tojo, A. Okada, V. Troiani, N. Solladié, T. Majima, J. Phys. Chem B.
2005, 109, 33-35. b) M. Fujitsuka, D. W. Cho, N. Solladié, V. Troiani, H. Qiu, T. Majima, J. Photochem.
Photobiol. A
2007, 188, 346-350.

Figure 1
Rapid Identification of Highly Corrosion Resistant Alloy Compositions
Authors: Summers Kodi , Lannoy Nathan , LaCombe Jeffrey , Chidambaram Dev
Published: February 2020

Typically, corrosion studies are conducted over large areas (mm2 – cm2) which make them inadequate to investigate corrosion behavior of localized areas of interest. To address the above shortcoming, a number of micro-electrochemical methods have been investigated over the past couple decades. This presentation will report the results from the microelectrochemical corrosion studies conducted on diffusion couples, which form the initial studies in the development of High Entropy Alloys (HEAs) or Multi-Principal Component Alloys. The study will discuss methods to identify compositions of lightweight alloys that have high corrosion resistance and exhibit reasonable mechanical properties compared to commercial alloys.
Corrosion Behavior of Cocrfemnni High-Entropy Alloys (HEAs) Under Aqueous Acidic Conditions
Authors: Rodriguez Alvaro , Tylczak Joseph H , Ziomek-Moroz Margaret
Published: February 2020

Research on new technologies in the field of advanced materials have contributed to the development of high-entropy alloys (HEAs), a relatively new family of multicomponent alloys composed of at least five alloying elements with an atomic composition of 5-35 % each by offering a configurational entropy of mixing ΔSconf of at least 1.5R, where R is the gas constant. The incorporation of a larger number of elements with high concentrations leads to new material properties by changing physical and metallurgical aspects that offer superior magnetic, mechanical, and electrochemical characteristics.

Literature data indicate that the oxidation resistance of eight HEAs in the CoCrFeMnNi family was studied by monitoring mass change oxidation kinetics at 650°C and 750°C for 1100 hours in comparison with the performance of commercially available alloys, nickel-based superalloy 230 (N06230) and austenitic stainless steel 304H (S30409) [1]. Results from this investigation revealed greater oxidation resistance from some multicomponent alloys compared to 230 and 304H alloys; and it is influenced by HEAs Cr or Mn compositional dependence, gaining valuable knowledge for their future use in commercial applications.

The purpose of this research was to evaluate the corrosion behavior of these advanced materials under aqueous acidic conditions by exposing the multicomponent alloys to immersion testing, and study their electrochemical kinetics versus the corrosion performance of Hastelloy® C276 (UNS N10276) and stainless steel 316L (UNS 31600). The HEAs selected are considered for corrosion protection applications of natural gas transmission pipelines. Weight loss analysis revealed the corrosion rates of these materials while changes on the metal surface were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Potentiodynamic polarization curves elucidated active, active-passive, and passive regions of these alloys to determine the presence of localized corrosion. Experiments were carried out under deaerated aqueous conditions of 3.5 wt.% NaCl solutions at pH 4 and temperature of 40°C. Oxygen content is suppressed from the environment by using CO2 as stripping gas.

Reference: G.R. Holcomb, J. Tylczak and C. Casey, JOM, 67 (2015) 2326-2339
Study on the Effect of Surface Finish on Corrosion of Carbon Steel in CO2 Environment Revisited
Authors: Yepez Omar Jesus
Published: February 2020

To study the effect of surface finish is important to predict corrosion rate that happen in the as-delivered internal pipe surface. In between the very few systematic studies of this effect on carbon steel under carbonic acid attack, it was concluded CO2 corrosion increased with increasing surface roughness. Nevertheless, previous studies has probe onto mild corrosion conditions (room temperature, one atmosphere of pressure). Given that the formation of a tenacious iron carbonate scale can protect the surface, it is important to perform these studies at harder conditions. In this paper, we present evidence that corrosion rate can do the opposite, it can increase as the surface roughness decrease. This, however, occurs for the same reason. A rougher surface can react faster and therefore, produce a protective iron carbonate layer.