bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monolithic Wireless Photoelectrochemical Device Design for Efficient Water Splitting Applied to Amorphous Silicon and III-V Photovoltaic Material
Authors: Koonce Jonathan G , Cheng Wei , Lee Joun , Rassoolkhani Alan , McKee Austin , Mubeen Syed 
Published: May 2020

Considerable research has been done by many groups for the creation of a standalone and integrated photoelectrochemical water splitting device that generates hydrogen using only energy from the sun. However, there remains significant challenges for improving the efficiency and long-term stability of such devices. Many hydrogen and oxygen evolving catalysts are active in concentrated acidic or basic electrolyte which necessitates schemes for protecting the photovoltaic material of choice from chemical and electrochemical corrosion. It is also necessary to optimize catalyst activity and loading for best solar-to-hydrogen efficiency.
Here we demonstrate a device structure applied to both a triple-junction amorphous silicon solar cell as well as a triple-junction III-V gallium arsenide solar cell. This design demonstrates efficient and stable water splitting which can be applied to any existing photovoltaic material. The triple-junction silicon device demonstrates application to cheap, commercially available solar cells. Devices made from these solar cells are anodic on the light absorbing side – which often suffer from accelerated decomposition due to corrosion from undesired photo-oxidation on the device surface. Similarly, the triple-junction gallium arsenide device demonstrates the application of this device structure to a high efficiency PV cell with opposite charge carrier orientation (cathodic reaction on light absorbing side of the device).
This design decouples the protective coating from the integrated catalysts, which allows the optimization of the transparent protective coating in the corrosive electrolyte to be tuned separately from the activity of the OER or HER catalysts. Our most efficient device shows over 10% solar-to-hydrogen efficiency and our best stability shows over 100 hours of operation.
Asymmetric Strain in the Oxidized and Reduced States of Heterogeneous Electrocatalysts
Authors: Smith Rodney D. L. 
Published: May 2020

The growing number of functional examples of “strain engineering” is drawing attention to the influence that mechanical or geometric considerations can have on the electronic structure and electrochemical behavior of electrocatalysts. It will be shown that the concept of lattice strain, and the changes in electronic structure that accompany it, can explain the experimentally observed trends in electrochemical behavior of common mixed-metal oxide catalysts for the oxygen evolution reaction. Structural analysis of a series of iron-nickel hydroxide materials reveal a significant change in O-Ni-O bond angles upon electrochemical oxidation.1 Subsequent analysis shows that insertion of ions with varied ionic radii into a Ni(OH)x host lattice introduces localized geometric distortions in the nickel environments that can be observed by tracking Ni-based d-d transitions in the near-infrared.2 The type (tensile or compressive) and magnitude of strain is correlated to the oxidation state of nickel ions and the ionic radius of the secondary ion. Experimentally observed trends in electrochemical behavior track the ionic radius of the secondary ion, indicating that the degree of strain directly correlates to electrochemical behavior. Density functional theory calculations indicate that inequivalence of this internalized strain in the oxidized and reduced states of the catalyst material introduces asymmetry into the potential energy surface landscape. This asymmetry effectively decreases the activation energy for electron transfer and may simultaneously decrease the electrochemical transfer coefficient. Evidence suggests that the synthetic protocol employed exerts significant influence over the placement of secondary ions and ability to observe this effect.3

(1) Smith, R. D. L.; Pasquini, C.; Loos, S.; Chernev, P.; Klingan, K.; Kubella, P.; Mohammadi, M. R.; González-Flores, D.; Dau, H. Energy Environ. Sci
2018, 11, 2476–2485.
(2) Alsac, E. P.; Whittingham, A.; Liu, Y.; Smith, R. D. L. Chem. Mater.
2019, 31, 7522–7530.
(3) Rong, W.; Stepan, S.; Smith, R. D. L. MRS Adv.
2019, 4, 1843–1850.
Electron Transfer-Catalyzed Vinylcyclopropane Rearrangements
Authors: Okada Yohei , Maeta Naoya , Kamiya Hidehiro 
Published: May 2020

Recently, electron has been recognized as the simplest catalyst in the field of synthetic organic chemistry. Addition or removal of electron can activate small molecules for further chemical transformations, which is referred to as redox catalysis. Reductive and/or oxidative single electron transfer (SET) can be induced by means of electro- and photochemistry, where an electron can play a role of catalysts. Radical ions are primarily generated via SET, offering unique reactive intermediates.
Distonic radical ions are transient species with formally separated radical and charge cites. They potentially exhibit radical and ion reactivities independently, which may differ from usual radical ions. However, distonic radical ions are not commonly used as reactive intermediates in the field of synthetic organic chemistry, probably because of lack of their simple generation methods.
We have been developing oxidative SET-triggered cycloadditions in a lithium perchlorate/nitromethane solution. Radical cations are involved in the reactions as distinctive reactive intermediates, facilitating intermolecular carbon-carbon bond formations. We questioned whether the distonic radical cation can also be generated by oxidative SET, leading to novel chemical transformations. In this presentation, oxidative SET-catalyzed vinylcyclopopane rearrangements will be described.

Figure 1
Site-Selective Modification of Conductive Materials By Bipolar Electropolymerization
Authors: Inagi Shinsuke , Koizumi Yuki , Watanabe Tempei , Zhou Yaqian , Shida Naoki , Nishiyama Hiroki , Tomita Ikuyoshi 
Published: May 2020

Electrooxidative coupling polymerization of aromatic monomers affords π-conjugated polymers. Conducting polymers are generally insoluble in solvents and are thus deposited on the surface of an anode during polymerization. This film formation is one advantage of electropolymerization because the chemical oxidative polymerization of aromatic monomers using chemical oxidants affords only insoluble powder or bulk of the corresponding polymers. This advantage is potentially useful for wide variety of applications, such as in electronics and sensors.
Recently, bipolar electrodes (BPEs) are available as wireless electrodes that undergo anodic and cathodic reactions at their terminals. When electropolymerization of aromatic monomers is conducted on a BPE, which is known as bipolar electropolymerization, this results in the wireless and site-selective formation of conducting polymer films or clusters at one terminal of the BPE. The alternating current (AC) bipolar electropolymerization of 3,4-ethylenedioxythiophene (EDOT) successfully provides microfibers of the corresponding polymer, poly (3,4-ethylenedioxythiophene) (PEDOT), grown from both terminals of the BPE. In this context, the bipolar method is next-generation electropolymerization that can site-selectively modify wireless electrodes with conducting polymers to afford novel hybrid materials. Herein, the concept of bipolar electropolymerization and recent examples are described.
Electrochemical Monitoring of Metallic Materials' Surfaces with Biofilm Formation
Authors: Kanematsu Hideyuki , Itoh Reo , Ogaki Sho , Hirai Nobumitsu , Kogo Takeshi , Ogawa Akiko , Wada Noriyuki , Tsunashima Katsuhiko , Barry Dana M. 
Published: May 2020

Biofilms formed on materials by bacterial activity cause many engineering problems. It ranges from those at hospitals to toilets and kitchen at homes in various ways. To solve those problems, it is very important to analyze the phenomenon precisely and also to monitor the formation and growth process. To achieve the purpose, we have had many proposals for biofilm sensors so far. However, there are not so many proposals for rapid, easy and industrial biofilm sensors. In this research, we established the electrochemical system to monitor biofilm formation and growth to measure the equilibrium (static) potential and also dynamic polarization curves of metallic materials. And we discussed on how we should apply the results to evaluate biofilms on metallic materials.
We used pure copper, titanium, iron and their alloys as specimen. The lead wire was attached to the tiny coupons (10mm x 10mm) and only the opposite side was exposed as electrode. Specimens (working electrode), helical platinum wire (counter electrode) and silver/silver chloride glass electrode in 3.3M KCl solution (reference electrode) were immersed into LB culture with E.coli (K-12, G6). And those three electrodes were connected to a potentiostat. The static potential change and polarization curves in the solution were measured, while the bacterial growth and biofilm formation/growth were going on.
The equilibrium potentials for copper, iron and their alloys were shifted in less noble direction, while those of titanium and their alloys did not change and were almost constant. And the polarization curves were also reflected correspondingly. Those changes were discussed and they could be explained by the biofilm formation and growth.
Lipids Lay Thyselves Down: Redox-Induced Lipid Vesicle Fusion Onto Ferrocene-Terminated Self-Assembled Monolayers
Authors: Hmam Ons , Badia Antonella 
Published: May 2020

Due to the attractive electrochemical properties of ferrocene (fast electron transfer, low oxidation potential, and two stable redox states), ferrocenylalkanethiolates on gold are the most studied and employed electroactive self-assembled monolayer (SAM) system. Oxidation of the SAM-confined ferrocenes to ferroceniums is accompanied by the formation of ion-pairs with counter-ions in solution [1,2].
Ferrocene-terminated SAMs exhibit a reversible electrochemistry in the presence of anionic surfactants such as n-alkyl sulfates and sulfonates, while the less chaotropic n-alkyl phosphates and carboxylates lead to the irreversible oxidation of the SAM-confined ferrocene (Fig. A) [3]. Cyclic voltammetry indicates that these latter surfactants form strong ion pairs with the oxidized ferroceniums; an oxidation peak is observed for the first anodic potential sweep but no reduction peak is detected during the reverse sweep. No redox peaks are observed in subsequent sweeps. The surface plasmon resonance signal does not return back to its original value during reduction, indicating an irreversible adsorption of material to the surface, which in turn suggests the formation of a stable and insoluble ferrocenium-surfactant anion complex or deposit that blocks the redox process. In this work, atomic force microscopy is used to investigate the association of sodium n-dodecanoate to the SAM surface.
This electrochemical approach appears to be an effective strategy for triggering the formation of solid-supported lipid membranes by the fusion of phospholipid vesicles onto the ferrocenylalkanethiolate SAM. In fact, phospholipids are double-tailed amphiphiles and these can associate with the oxidized ferrocene (Fig. B). A potential-step hold at 0,64 V for only five minutes induces the immediate adsorption of phosphatidylserine (DMPS, POPS and DOPS) at the SAM-gold/electrolyte interface with a full surface coverage. This technique is a versatile tool that offers many benefits such as, a faster supported lipid bilayers formation mimicking the biological membranes, a larger variety of lipid composition, structure and chemical nature, and a possibility of using metal surfaces considering their potential applications in electrochemical techniques, spectroscopic techniques and surface plasmon resonance. In this work, AFM-based nano-shaving, force spectroscopy, and surface plasmon resonance are combined to determine the thickness of the obtained lipid membrane.

References

[1] E. Dionne, T. Sultana and A. Badia, J. Am. Chem. Soc.
135, 17457-17468 (2013).
[2] E. Dionne and A. Badia, ACS Appl. Mater. Interfaces
9, 5607-5621 (2017).
[3] A. Salis and B. W. Ninham, Chem. Soc. Rev.
43, 7358-7377 (2014).

Figure 1
Morphology Control to Enable High Capacity Li-Rich Disordered Rock Salt Cathodes
Authors: Chung Hyeseung , Doux Jean-Marie , Grenier Antonin , Meija Carlos , Sayahpour Baharak , Meng Ying Shirley 
Published: May 2020

Li-rich disordered rock salt (DRS) oxides are a promising class of cathode materials with the wide chemical space to be explored. The high capacity (>300mAh/g) of this class of material can be explained by the reversible redox chemistry of the oxide anions, which sets it apart from the conventional layered cathode materials that rely only on the transition metal redox. However, these materials suffer from poor ionic and electronic transport properties: Most previous studies report electrochemical performance at low current rate and elevated temperature. Even then, the particle size needs to be reduced to sub-micrometer size, often by high-energy ball milling, to get reasonable capacities.
To mitigate this issue, we performed a detailed study of the synthesis of three different Nb-based Li-rich DRS materials - Li3NbO4, Li1.3Fe0.4Nb0.3O2, and Li1.3Mn0.4Nb0.3O2. Systematic evaluation shows that both the synthesis conditions and the reagents used have a large effect on the phase and morphology of the material synthetized, and therefore on its electrochemical performance. Without varying the synthesis method, the extent of cation ordering, the particle morphology, and the degree of elemental segregation can be controlled by a careful choice of the metal oxide precursors. This study helps the community to distinguish important synthesis criteria in order to design Li-rich DRS cathode materials with improved electrochemical performance.
Observation of Lithium Dendrite Growth on Llzo-PEO Solid Electrolyte
Authors: Bunyanidhi Panyawee , Phattharasupakun Nutthaphon , Duangdangchote Salatan , Krittayavathananon Atiweena , Sawangphruk Montree 
Published: May 2020

Solid-state electrolytes have been discovered as an alternative to liquid electrolyte on lithium-based batteries. Among all solid electrolytes, poly (ethylene oxide) based-solid electrolytes (PEO) have the advantages of low flammability, good flexibility, and excellent thermal stability. The major problem limiting the rate capability of PEO-based electrolyte in the lithium metal battery during charging is the issue of lithium penetration through the PEO electrolyte that results in short circuits 1. To overcome these drawbacks, we have added the ceramic fillers (i.e., garnet (Li7La3Zr2O12) etc.) in a ratio of 10-40% in the polymer host matrix. The garnet ceramic filler contributes to reduce the crystallinity of polymer and so to increase the ionic conductivity. The ceramic in polymer also provides higher mechanical strength that can reduce the lithium dendrite formation 2. To investigate the formation of lithium dendrite, we show a detailed study of lithium metal deposition on the LLZO-PEO electrolyte using ex-situ electrochemical and electron microscopic methods.

Keywords: Solid-state lithium batteries, Solid polymer electrolyte, Garnet, Polymer-ceramic composite electrolyte, Lithium dendrite

REFERENCES

1. J. Mindemark, M. J. Lacey, T. Bowden and D. Brandell, Progress in Polymer Science, 2018, 81, 114-143.
2. W. Zhang, J. Nie, F. Li, Z. L. Wang and C. Sun, Nano Energy, 2018, 45, 413-419.

Figure 1
Study of Li Metal/C Paper Electrodes for Li/S Batteries By Operando Dilatometry
Authors: Fatahine Mohamed , Guay Daniel , Roué Lionel 
Published: May 2020

The use of Li metal anode in rechargeable batteries such as Li-S and Li-air is challenging due to the uncontrolled formation of lithium dendrites during repeated charge/discharge cycling, which induces various issues such as cell short circuit, aggravated adverse reactions, dead Li formation, polarization increase and large volume changes, resulting in safety concerns and low coulombic efficiencies [1]. Different characterization techniques have been used to study Li metal electrode morphological changes associated with Li dendrite formation such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy and optical microscopy [2]. A large part of these characterizations were performed ex situ or in situ but under static conditions (no cycling) or operando using open cell requiring none volatile electrolyte, giving limited information on the Li growth dynamics in real systems. Recently, operando synchrotron X-ray tomography has been used to visualize the morphological evolution of Li metal electrodes in various cell configurations (e.g. Li-S cell [3]). However, the limited access to beamtime at synchrotron X-ray sources and challenges with data processing (image segmentation, volume reconstruction, artefact minimization, etc.) are major drawbacks.
In the present study, a simple and low-cost method is used to monitor the electrode thickness variation associated with the Li plating/stripping process. This technique, named ‘’electrochemical dilatometry’’, consists in integrating a gap sensor or a displacement transducer within the electrochemical cell for measuring the vertical displacement of the working electrode during its cycling. It has been successfully applied for studying the volume expansion/contraction of Si-based electrodes for Li-ion batteries [4]. To the best of our knowledge, electrochemical dilatometry has never been applied to the study of Li metal electrodes. In the present study, this technique is used for studying the expansion/contraction behavior of electrodes integrating commercial porous C papers as 3D matrices for Li electrodeposition and compared to what is observed on a 2D Cu foil substrate (Figure 1).

References

[
1
] X.B. Cheng, R. Zhang, C.Z. Zhao, Q. Zhang, Toward safe lithium metal anode in rechargeable batteries: a review, Chem. Rev 117 (2017) 10403-10473.

[
2
] D. Lin, Y. Liu, Y. Cui, Reviving the lithium metal anode for high-energy batteries, Nat. Nanotechnol. 12 (2017) 194-206.

[
3
] G. Torin, G. Vaughan, R. Boucher, F. Alloin, M. Di Michiel, L. Boutafa, J.F. Colin, C. Barchasz, Multiscale characterization of lithium/sulfur battery coupling operando X-ray tomography and spatially-resolved diffraction, Sci. Rep. 7 (2017) 2755.

[
4
] A. Tranchot, P-X. Thivel, H. Idrissi, L. Roué, Impact of the slurry pH on the expansion/contraction behavior of silicon/carbon/carboxymethylcellulose electrodes for Li-ion batteries. J. Electrochem. Soc. 163 (2016) A1020-A1026.

Figure 1
Challenges of Nanoscale Characterisation of Litihum-Based Energy Materials
Authors: Voisard Frédéric , Brodusch Nicolas , Trudeau Michel , Zaghib Karim , Gauvin Raynald 
Published: May 2020

The electric energy revolution is driven by battery technology. New chemistries and control systems enables the widespread use of portable electric devices, such as phones, computers, power tools and automobiles. The upward trend in battery performance relies on continuous research[1]. Scanning transmission electron microscopy (STEM) is a commonly used tool for nano-scale characterisation, as it allows for imaging as well as elemental and chemical analysis, when combined with energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS)[2], [3]. EELS is a particularly useful technique, as the near-edge structure of the ionization edges often give chemical bonding information. However, the high energy electron beam used in STEM can damage materials[4]. This is especially problematic in the field of battery research. Low-Z elements such as lithium, carbon and oxygen, are particularly susceptible to knock-on damage[4]. Since these elements are common in lithium-ion batteries, understanding how the beam affects materials is critical to the analysis of the materials.
Commercially pure chemical compounds (LiF, LiCl, Li2CO3), acquired from MilliporeSigma, are exposed to the microscope beam, under condition favorable for EELS analysis of the Lithium K-edge. An EELS spectrometer is used to serially acquire energy loss spectra of the materials. These time-sensing series show how the near edge structure of lithium evolve as the material is damaged by the beam. In this work, the abherrent effects of the electron microscope on lithium samples is made evident.
[1] J. B. Goodenough and K.-S. Park, “The Li-Ion Rechargeable Battery: A Perspective,” Journal of the American Chemical Society, vol. 135, no. 4, pp. 1167–1176, Jan. 2013.
[2] D. B. Williams, Transmission electron microscopy: a textbook for materials science, 2nd ed. New York: Springer, 2008.
[3] J. I. Goldstein et al., Scanning Electron Microscopy and X-Ray Microanalysis a Text for Biologists, Materials Scientists, and Geologists. Boston, MA: Springer US, 1992.
[4] R. F. Egerton, “Mechanisms of radiation damage in beam-sensitive specimens, for TEM accelerating voltages between 10 and 300 kV,” Microsc. Res. Tech., vol. 75, no. 11, pp. 1550–1556, Nov. 2012.

Figure 1
Synthesis of Na-MnO₂ Electrodes and Its Microstructural and Electrochemical Characterization.
Authors: Cuéllar Herrera Lorena Guadalupe , Romero Serrano Jose Antonio , Estrada-Arce Elsa Miriam 
Published: May 2020

The batteries are portable devices that allow to storage chemical energy and provide electric current directly. Inside the batteries, one of the most used materials is Lithium, which includes a large number of applications.
In recent years, the investigation of ion-Na and Na-MnO₂ batteries has been intensified as an alternative to Li-MnO₂ batteries. Lithium and sodium have many similar chemical characteristics and their low cost and the wide availability of sodium are factors that can make them more used in the future. An important concern in the increase of lithium battery production lies in the limited natural resources provided by this material, and its heterogeneous distribution in the earth's crust
This work is focused on the preparation of Na-MnO₂ electrodes for secondary batteries and the microstructural, structural, and electrochemical characterization of them. The synthesis technique was hydrothermal non-conventional type. The contributions are found in the comparison of the properties and electronic elements of the synthesized materials. The impact of this project is on the possible use of Na-MnO₂ electrodes as an alternative material to the one currently used in Li-MnO₂ batteries.

Figure 1