bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleation and Surface Passivation in Li-Air Batteries
Authors: Shen Chao , Andrei Petru , Zheng Jim P. 
Published: February 2020

Recently, there has been increased evidence that the lithium peroxide in Li-oxygen batteries forms as a result of a continuous nucleation process followed by a growth process [1, 2]. This deposition mechanism is intrinsically heterogeneous and is microscopically different from the traditional approach in which the final product grows uniformly as a thin resistive layer on the surface of the electron conductive material [3, 4]. Similarly to the nucleation and growth of lithium sulfide in Li-S batteries, the deposition of Li2O2 in Li-oxygen batteries starts with the formation of initial Li2O2 seeds and subsequent growth of the Li2O and/or Li2O2 product on the surface of the seeds. This growth can be in the form of direct precipitation of Li2O2 molecules or disproportionation reactions involving LiO2 and Li2O2. In this presentation we introduce a mathematical model that describes the precipitation and growth mechanism in the form of a system of differential equations appropriate for implementation in finite element simulators. In agreement with the classical nucleation theory, the driving force of the nucleation process in our model is the oversaturation of the depositing species. Therefore, the nucleation seeds appear when there is a critical oversaturation condition on the surface of the carbon; the number of nucleation seeds increases in time during the discharge of the battery at a rate which is proportional to the discharge rate of the battery. The model explains quantitatively well the decrease of the specific capacity with the discharge rate and also explains the relatively large Li2O2 grains observed in the cathode of discharged Li-air batteries.
[1] S. Lau, L.A. Archer, Nucleation and Growth of Lithium Peroxide in the Li–O2 Battery, Nano Letters, 15 (2015) 5995-6002.
[2] Y. Yin, A. Torayev, C. Gaya, Y. Mammeri, A.A. Franco, Linking the Performances of Li–O2 Batteries to Discharge Rate and Electrode and Electrolyte Properties through the Nucleation Mechanism of Li2O2, The Journal of Physical Chemistry C, 121 (2017) 19577-19585.
[3] A.C. Luntz, V. Viswanathan, J. Voss, J.B. Varley, J.K. Nørskov, R. Scheffler, A. Speidel, Tunneling and Polaron Charge Transport through Li2O2 in Li–O2 Batteries, The Journal of Physical Chemistry Letters, 4 (2013) 3494-3499.
[4] P. Andrei, J.P. Zheng, M. Hendrickson, E.J. Plichta, Some Possible Approaches for Improving the Energy Density of Li-Air Batteries, Journal of the Electrochemical Society, 157 (2010) A1287-A1295.
Transient Study of Adsorbed Oxygen Species Arising from Exposure to Dissolved Oxygen
Authors: Rodríguez Oliver , Denuault Guy 
Published: February 2020

Recently, adsorbed oxygen species (adspecies) have been detected at the millisecond scale on different metallic microelectrodes after being exposed to dissolved oxygen 1,2 . Comparing the experimental current of the oxygen reduction reaction (ORR) with a theoretical diffusion controlled current, it was revealed that both, the adsorbed and diffusion controlled species, were being reduced at the same time. To study the adspecies independently, it is necessary to decouple the contribution of each process. Here, we show that this can be done by controlling the availability of the gas present in solution as well as the potential waveform applied. After the separation, the diffusion controlled current reveals how n
app, the apparent number of electrons for the ORR, depends on km
, the mass transfer coefficient. On Pt microdiscs, n
app decreased from 4 to 2 as the mass transfer coefficient was increased by decreasing the disc radius or the timescale of the experiment. This effect was previously observed at the steady state with rotating disc and microelectrodes, but its dependency on transient conditions has never been reported 3, 4. Meanwhile, the decoupled desorption current was found to follow a second order process which would be consistent with the production of H2O2 via dimerization of OH radicals. These desorption currents were used to estimate the desorption rate constant and maximum coverage of the adspecies as a function of the applied potential. Our results indicate that the amount of adsorbed species left after exposure to dissolved oxygen is below 0.1 of a monolayer, in agreement with previously reported values 1, 2. The high sensitivity of the methodology presented here reveals the subtle effects arising from exposure to dissolved oxygen.
(1) Perry, S. C.; Denuault, G. Transient Study of the Oxygen Reduction Reaction on Reduced Pt and Pt Alloys Microelectrodes: Evidence for the Reduction of Pre-Adsorbed Oxygen Species Linked to Dissolved Oxygen, Chem. Chem. Phys.
2015, 17 (44), 30005-30012.
(2) Perry, S. C.; Denuault, G. The Oxygen Reduction Reaction (ORR) on Reduced Metals: Evidence for a Unique Relationship Between the Coverage of Adsorbed Oxygen Species and Adsorption Energy, Chem. Chem. Phys.
2016, 18, 10218-10223.
(3) Pletcher, D.; Sotiropoulos, S. A Study of Cathodic Oxygen Reduction at Platinum Using Microelectrodes. Electroanal. Chem. 1993, 356 (1-2), 109-119.
(4) Sosna, M.; Denuault, G.; Pascal, R. W.; Prien, R. D.; Mowlem, M. Development of a Reliable Microelectrode Dissolved Oxygen Sensor. Sensors Actuators, B Chem. 2007, 123 (1), 344-351.
High Magnetic Field Effects on Al Electrodeposition in AlCl3-Emic Ionic Liquid
Authors: Matsushima Hisayoshi , Takahashi Hitomi , Mogi Iwao , Ueda Mikito 
Published: February 2020

1.Introduction
Aluminum is a very important material because of its distinctive features of a bright silvery appearance, light weight and high corrosion resistance. Also, it is used as a base in light-emitting diodes owing to its high reflectance of more than 90% in the visible light region. We have been investigating Al electrodeposition in a magnetic field. The surface morphology changed remarkably in the presence of a magnetic field, where the large grains with tabular-face were created [1]. This is explained by MHD convection induced by Lorentz force.
We consider that the MHD convection can act more effectively as compared with an aqueous solution system, since an ionic liquid consists of only ion species. In this report, Al films were electrodeposited in EMIC-AlCl3 ionic liquid under a superconducting magnet. Their morphology and crystal orientation were analyzed by scanning electron microscopy and X-ray diffractometry.

Experimental

Electrodeposition was carried out with a three-electrode system. The electrolyte used was EMIC-AlCl3 (1:2). The cathode was a Cu plate and the anode was an Al plate. All experiments were conducted in a glove box purged using by Ar gas at 60°C. The Al electrodeposition was conducted galvanostatically until the amount of electrical charge reached 29 C cm−2, which corresponds to a deposition 10 µm thick. A superconducting magnet up to 5 T was applied parallel to the electrode surface. The surface morphology of the electrodeposited Al films was observed using SEM, while the crystal orientation was measured by XRD using the Cu-Kα line.

Results and discussion

Figure 1 shows the SEM image of the Al electrodeposited surface without a magnetic field and with a magnetic field of 5 T. When no magnetic field is applied, there were many grains on the surface and the deed groove was seen (Fig. 1 (a)). On the other hand when 5 T was applied parallel to the electrode surface, the grooves between the grains were buried and a very smooth surface was observed (Fig. 1 (b)). Because the MHD convection was generated by the magnetic field, the ions were supplied to the vicinity of the trench between the grains. This was attributed to the uniform electrodeposition.
In order to evaluate the crystal orientation of the Al films obtained by electrodeposition, XRD measurement was carried out. When the magnetic field was not applied, the (200) plane showed a very strong orientation compared with other crystal faces. In the magnetic field, the orientation of the (200) plane decreased with the increase of the magnetic flux density, while the crystal growth of the (111) and (220) planes were progressed.
[1] H. Takahashi, H. Matsushima and M. Ueda, J. Electrochem. Soc., 164, H5165 (2017).

Figure 1
Activity and Selectivity Control in CO2 eectroreduction through Catalyst and Electrolyte Design
Authors: Roldan Cuenya Beatriz 
Published: February 2020

The electrochemical conversion of CO2 (CO2RR) into chemicals and fuels is of industrial significance since it might lead to a more efficient storage of renewable energy while closing the carbon cycle.
This talk will focus on model nanostructured plasma-activated dendrites and nanoparticle (NP) electrocatalysts (Cu, Ag, Zn, Cu-M with M = Co, Zn and Ag-Sn) for the electrocatalytic reduction of CO2. We will show how to tune catalytic selectivity based on rational catalyst and electrolyte design involving controlling the NP size, shape, support interaction, as well as the electrolyte properties by adding cations and anions (Cs+, Li+, Na+, K+, I-, Br-, Cl-). 1-5

In situ and operando spectroscopic and microscopic methods have been used to gain insight into the correlation between the structure, chemical state, and reactivity of ligand-free size- and shape-controlled spherical and cubic NPs as well as plasma-activated dendritic structures and Cu single crystals during CO2RR. Dynamic changes in the morphology and composition were monitored under potential control via electrochemical atomic force microscopy, X-ray absorption fine-structure spectroscopy and quasi in situ X-ray photoelectron spectroscopy. Additionally, density functional theory calculations were used to provide new insights on the active sites and reaction mechanism of the former electrocatalysts, including the role of different electrolytes. Our results are expected to open up new routes for the reutilization of CO2 through its direct selective conversion into higher value products.
1. P. Grosse, D. Gao, F. Scholten, I. Sinev, H. Mistry, B. Roldan Cuenya, Angewandte Chemie (2018) in press.
2. H. S. Jeon, S. Kunze, F. Scholten, B. Roldan Cuenya, ACS Catal. 8 (2018) 531
3. H. Mistry, Y. Choi, A. Bagger, F. Scholten, C. Bonifacio, I. Sinev, N. J. Divins, I. Zegkinoglou, H. Jeon, K. Kisslinger, E. A. Stach, J. C. Yang, J. Rossmeisl, B. Roldan Cuenya, Angew. Chem. 56, 11394 (2017)
4. D. Gao, F. Scholten, B. Roldan Cuenya, ACS Catal. 7, 5112 (2017)
5. D. Gao, I. Zegkinoglou, N. J. Divins, F. Scholten, I. Sinev, P. Grosse, and B. Roldan Cuenya, ACS Nano 11, 4825 (2017)
Investigations of the Structural and Electrochemical Properties of Partially Abused Li-ion Batteries for Advanced Diagnostics
Authors: Deichmann Eric , Torres-Castro Loraine , Lamb Joshua , Karulkar Mohan 
Published: February 2020

Establishing a framework for understanding the degradation mechanisms of lithium-ion batteries (LIBs) subjected to abusive conditions has become increasingly important in recent years, as LIBs continue to capture new markets involving an array of abuse-prone applications such as electric vehicles, aircraft, and mobile energy storage systems. Characterization techniques used to identify the state-of-health (SoH) of LIBs can identify a range of degradation mechanisms, which can be broadly categorized as loss of lithium inventory (LLI), loss of active material (LAM), and conductivity loss (CL). These degradation mechanisms, which have been well characterized in literature, are established using a variety of in-situ and ex-situ techniques. The most common in-situ technique for determining cell SoH involves monitoring temperature and voltage as a function of state of charge (SOC) throughout cell cycling. For abusive conditions, however, this measurement is a particularly poor indicator of battery SoH and does not provide valuable insight into cell degradation until failure is imminent. It is particularly difficult to determine SoH for LIBs, as the voltage curve maintains a relatively uniform profile until moments before cell failure. A more versatile in-situ technique capable of monitoring battery degradation mechanisms is Electrochemical Impedance Spectroscopy (EIS), which quantifies cell SoH by measuring system response to a range of sinusoidal excitation signals at varying frequencies. Although extensive characterization of battery degradation has been conducted using traditional EIS hardware, no research has been conducted on impedance analysis of active load cells subjected to abusive conditions.
This work attempts to identify failure markers by linking impedance measurements captured using the EIS toolbox to previously established degradation mechanisms for abused cells. In-situ EIS measurements were collected, followed by identification of failure markers using ex-situ material characterization of harvested electrodes. Failure markers were established by linking degradation behavior identified by material characterization methods to changes in impedance behavior observed by the toolbox. This data can be extrapolated for use with general LIB chemistries in a wide range of BMS’s. Although data extrapolation is outside the scope of this work, data obtained will help facilitate future extrapolation of failure markers to a wide range of LIB chemistries.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
The Role of DMSO As an Electrolyte Additive in Alkaline Zinc-Air Flow Battery
Authors: Hosseini Soraya , Kheawhom Soorathep 
Published: February 2020

Zinc-air batteries are attractive electrical energy storage due to their cost effectiveness, high specific energy density, and safety. Traditionally, the batteries use alkaline solution as an electrolyte. Besides, electrolyte additives such as potassium sulfide, zinc oxide, ethanol, surfactants, bismuth oxide, and iron oxide were introduced to suppress zinc anode passivation and corrosion. Dimethyl sulfoxide (DMSO) is one of the potential additives capable of inhibiting zinc anode passivation and corrosion effectively. This work investigates the application of DMSO in an alkaline zinc-air flow battery. Adding DMSO to potassium hydroxide (KOH) aqueous solution electrolyte revealed the positive effects on zinc dissolution.
The effects of DMSO were studied by cyclic voltammetry of Fe(CN)6
3-/Fe(CN)6
4- redox couple reaction using the scan rate of 0.05 mV/s. A pair of sharp cathodic and anodic peaks were observed at 0.2 and 0.7 V (vs. Hg/HgO), corresponding to the redox reaction related to Fe(CN)6
3-/Fe(CN)6
4-. The reduction peaks between 0.04 and 0.2 V (vs. Hg/HgO) were observed for all electrolytes (KOH, DMSO/KOH). With increasing DMSO concentration from 1 to 20 v/v %, the redox peaks shifted towards less positive values. The results suggested that KOH undergoes an interaction with DMSO.
Besides, the effects of DMSO (0, 1, 5, 10 and 20 v/v %) in 0.1 M KOH electrolyte on the electrochemical performance of air-cathode using MnO2 oxygen reduction reaction (ORR) electrocatalyst was examined by a rotating disk electrode technique. Linear sweep voltammetry was recorded in a potential window from 0 to -1 V (vs. Hg/HgO) at a scan rate of 0.05 mV/s and rotation rates of 100 to 3600 rpm. The Koutecky-Levich equation was applied to study kinetics and mass transfer processes of ORR in the electrolyte containing DMSO and KOH. The presence of DMSO in KOH solution causes significant improvement in the limiting current density. Also, it was observed that the limiting current density for the 5 v/v % DMSO/KOH at 3600 rpm is higher than that of 20 v/v % and also higher than that attained by KOH. The calculated number of electron transfer in 5 and 20 v/v % DMSO/KOH were 3.2 and 2.75, respectively, whilst the number of electron transfer of 2.24 was obtained for KOH electrolyte without DMSO. Overall, the results indicated that using DMSO as an electrolyte additive significantly improve zinc anode performance as well as ORR electrochemical performance.

Figure 1
Metallomacrocycle-Driven Atomically Dispersed M-N
x
Sites on Carbon Nanostructures for Electrocatlyic Energy Conversion Reactions
Authors: Joo Sang Hoon 
Published: February 2020

Developing highly active, durable, and low-cost electrocatalysts is of crucial importance to making renewable energy conversion devices, such as fuel cells and electrolyzers, economically viable. Hence, tremendous efforts have been geared to develop non-precious metal electrocatalysts that can replace expensive precious metal catalysts for energy conversion reactions. Among various classes of non-precious metal electrocatalysts, transition metal and nitrogen codoped carbon (M–N/C) catalysts have demonstrated excellent catalytic activity, which even rivals that of precious metal catalysts. In this presentation, we present our recent efforts toward high-performance M–N/C catalysts for energy conversion reactions, including oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) [1-7]. We have developed a general “silica-protective-layer-assisted” approach that can preferentially generate the catalytically active M–N
x
sites in M–N/C catalysts while suppressing the formation of catalytically less active or inactive large metallic particles [4,6,7]. The catalyst preparation consisted of adsorption of a metallomacrocyle precursor on a carbon support, low-temperature annealing, silica layer overcoating, high-temperature pyrolysis, and silica layer etching, which yielded a carbon coated with thin layer of metallomacrocyclic carbon catalysts [4]. The prepared catalysts contained a higher density of active M–N
x
sites compared to the catalytic prepared without the silica coating step. This preparation method is generally applicable to various carbon supports and metallomacrocyclic compounds. The prepared Fe-containing catalysts showed very high ORR activity and excellent stability in alkaline media. Importantly, an alkaline anion exchange membrane fuel cell with a CNT/PC-based cathode exhibited record high current and power densities among NPMC-based AEMFCs. Furthermore, using metallomacrocycle precursors with Co, Ni, and Pt metal centers, catalysts showing excellent performances toward HER [7], CO2 reduction reaction [8] were developed.
References

Y. Cheon et al., Scientific Reports 3, 2715 (2013).

J. Han et al., Angew. Chem. Int. Ed. 54, 12622 (2015).

Y. Cheon et al., Adv. Energy Mater. 6, 1501794 (2016).

J. Sa et al., J. Am. Chem. Soc. 138, 15046 (2016).

H. Kim et al., ACS Appl. Mater. Interfaces 9, 9567 (2017).

Woo et al., Chem. Mater. 30, 6684 (2018).

J. Sa et al., ACS Catal. 9, 83 (2019).

J. Sa et al., manuscript in preparation (2019).
Erythropoietin Accelerates a Cancer Specific Porphyrins' Accumulation
Authors: Matsui Hirofumi , Kurokawa Hiromi 
Published: February 2020

Introduction: Erythropoietin (EPO) is a glycoprotein cytokine which stimulates red blood cell production (erythropoiesis) in the bone marrow. The receptor of it (EPOR) was reported to exist on the cancer cellular membrane: more than 85% cancer cell expresses EPOR. Several reports suggested to play an important role for cancer cellular growth, however, the role of EPOR in cancer cells is not confirmed. The authors have studied the cancer cellular porphyrin accumulation, metabolism and excretion to clear the pathogenic mechanism which involved the high concentration of porphyrins. The authors found that reactive oxygen species (ROS) accelerate both the cancer cellular porphyrin accumulation and the effect of photodynamic therapy. However, we cannot confirm which substrate is a key of signal transduction. EPO has been known used to be up-regulated at the metabolic acidosis via the stabilization of HIF-1α, a nuclear factor. Since HIF-1α can be stabilized by not only acidosis but also the high concentration of nitric oxide (NO), NO rich cancer cells may involve EPOR. Moreover, the purpose of EPO-EPOR system is likely to survive the hypoxic condition, it may keep intracellular heme/ porphyrins. The authors’ hypothesis is EPO-EPOR system in cancer cells may down-regulate ABCG2 which excretes heme/ porphyrins, and several anti-cancer drugs. Moreover, if so, the excretion of both porphyrins and several anti-cancer chemo reagents should be inhibited to involve more effective PDT and chemotherapy.
Methods: To prove these possibilities, the authors carry out following experiments with gastric and colorectal cancer cells. The existence of EPOR, the amount of ABC transporters (B1, C5, G2) after the recombinant EPO (rEPO) exposure (dose dependency and time dependency) were analyzed by western blotting. Cytotoxicity of both PDT and anti-cancer drugs with or without rEPO was measured with the Cell Counting Kit-8.
Result: (1) EPOR existed in each cell line used in this study. (2) rEPO treatment involved down regulation of ABC transporters (B1, C5, G2) in dose dependently. (3) ABCG2 expression decreased until 24 hours after rEPO treatment. However, its expression re-increased 48 hours after treatment. (4) The 24 hours pretreatment of EPO significantly increased the effect of PDT, doxorubicin, paclitaxel, irrinotecan, cisplatin, 5-FU and oxaliplatin even in chemo-resistant cells.
Conclusions: rEPO accelerates the effect of PDT and anti-cancer drugs via the down regulation of ABC transporters.
Photophysics of Phosphorus Corroles and Application of the Compounds in Triplet-Triplet Annihilation Upconversion
Authors: Zhao Jianzhang 
Published: February 2020

Triplet-triplet annihilation upconversion (TTA-UC) is in particular of interest, due to the strong absorption of the excitation light and the high upconversion quantum yields.[1,2] For TTA-UC, a proper triplet photosensitizer and a triplet acceptor are combined to perform the cascade photophysical processes to convert the photons with lower energy to photons with higher energy. Triplet photosensitizers are crucial for TTA-UC. The conventional triplet photosensitizers used for TTA-UC are transition metal complexes or organic compounds containing iodine or bromine atoms.[3] The rationales to use the heavy atoms are to employ the heavy atom effect to facilitate the ISC for triplet state formation upon photoexcitation. Heavy atom-free organic compounds were rarely used as triplet photosensitizers because the ISC is almost unpredictable without the heavy atom effect.[4]
Free base corrole is tetrapyrrolic macrocycle with one meso carbon less than porphyrins. Corrole compounds usually show strong absorption of visible light and high photo-stability, as well as efficient ISC. However, corroles were rarely used as triplet photosensitizers for TTA-UC. Herein we studied the photophysical properties of series of corroles with steady state and time-resolved spectroscopies. The corroles were used as triplet photosensitizers for TTA-UC, with perylenebisimide (PBI) as the triplet acceptor. Upon 589 nm cw-laser excitation, upconversion emission at 520 nm was observed. The upconversion quantum yield was determined as 1%.

References

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[2] J. Zhao, S. Ji, H. Guo. RSC Adv., 2011, 1, 937–950.
[3] J. Zhao, S. Ji, W. Wu, W. Wu, et al. RSC Adv., 2012, 2, 1712–1728.
[4] J. Zhao, W. Wu, J. Sun and S. Guo. Chem. Soc. Rev., 2013, 42, 5323–5351.