bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Principles Calculations of Interfacial Models for Nucleation Processes during NiO Conversion Reactions
Authors: Warburton Robert , Yildirim Handan , Fister Timothy T , Evmenenko Guennadi , Chan Maria K. Y. , Fenter Paul , Bedzyk Michael J. , Greeley Jeff 
Published: February 2020

Oxide conversion reactions may yield Li-ion battery electrodes with exceptionally high capacities in comparison to intercalation materials, with Li2O-encompassed transition metal nanoparticles as the ideal discharge product. Nanoscale confinement has been demonstrated to facilitate the reversibility of these conversion reactions1–3. The NiO conversion reaction, in particular, has a high theoretical capacity (718 mAh g-1), but there is significant hysteresis between the experimental and theoretical voltage (0.6 V and 1.9 V, respectively), and the molecular origins of this hysteresis are poorly understood. In this work, we will present an integrated computational modeling approach, using classical molecular dynamics and first principles density functional theory calculations, with classical nucleation theory, to directly probe the role of interfaces during NiO conversion. These efforts are informed, in part, by recent work suggesting a strong role of interfaces during conversion, as lithiated domains propagate from the surface to the bulk of NiO nanomaterials4. Different nucleation schemes are evaluated, considering potential-dependent bulk and interfacial free energies to determine critical nucleation radii and energy barriers, as well as possible mechanisms for exceeding theoretical capacity limits. Theoretical predictions are directly compared to experimentally observed Ni/NiO multilayer electrode morphologies determined from in-situ X-ray reflectivity measurements.
This research was supported as part of the Center for Electrochemical Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Electrochemical Characterization of Chitosan Films As Proton-Conducting Layers for Bioprotonic Devices
Authors: Pietron Jeremy , Robinson Jeremy T. , Blue Brandon , Josberger Erik , Deng Yingxin , Rolandi Marco 
Published: February 2020

We describe the lithographic fabrication, electrochemical characterization, and modeling of bioprotonic conduction channels, using a proof-of-concept material, chitosan, as a proton-conducting film deposited onto palladium electrodes. Linear sweep voltammetry (LSV) has been used to probe both the electrochemical generation of protons from H2 feed gas and the conduction of those protons through channels fabricated with different molecular weights of chitosan. Higher MW chitosan produces channels with significantly higher proton conductivity. Additionally, rigorous evaluation of the LSV data by both standard electroanalytical expressions and by digital simulation reveal that proton generation at the PdHx electrodes varies substantially between devices of different geometries. Multiple hydrogen oxidation reaction (HOR) pathways are operational at some devices, while at others a single pathway dominates. The analyses reveal the sensitivity of proton-generation kinetics on the chitosan/PdHxinterface, and furthermore, to the geometry of the device itself. Simulations of the proton conductivity in the chitosan membrane, however, yields excellent agreement between devices. Direct measurement of proton conductivity using electrochemical impedance spectroscopy further corroborates this agreement, yielding proton conductivity values nearly identical to those determined by analysis of the LSV results.
This work is supported by the Office of Naval Research.
In Situ and Operando Observation of Oxide Layer on Electrodes during the Oxygen Evolution Reaction
Authors: Toparli Cigdem , Rabe Martin , Erbe Andreas 
Published: February 2020

Water electrolysis is a promising approach of electrochemical energy storage.[1] The generation of molecular oxygen at the anode limits the efficiency of the water electrolysis by creating a large anodic overpotential during the overall water splitting process. In particular, the bottleneck is the high dissolution rate and instability of the metal/metal oxides under conditions of the oxygen reduction reaction (OER).[2] In this context, manganese oxides are candidates as earth abundant and low cost water oxidation electrocatalysts.[3]

This study compares the state of oxides during electrode polarisation up to potentials with OER and transpassive dissolution on two metals, manganese and copper.[4,5] For this purpose, metallic manganese and copper electrodes were prepared by physical vapor deposition. In situ spectroscopic ellipsometry was used to investigate the oxide growth and stability. From an analysis of ellipsometric spectra, based on a previous analysis procedure,[4,5] the oxide thickness was determined as a function of electrode potential, using chronoamperometry. The nature of oxides was studied through in situ Raman spectroscopy. Information on electronic structure was derived from analysis of spectroscopic data from ellipsometry, and by UV/VIS reflection measurements. In addition, the photoluminescence background in the Raman spectra contains valuable information. The spectroscopic data was complemented with ex situ analyses, including X-ray photoelectron spectroscopy (XPS). The current results suggest that the defect formation is critical for the oxide stability and that the oxides are highly dynamic under OER condition.
[1] M. G.Walter, E. L.Warren, J. R. McKone, S. W. Boettcher, Q. Mi, E. A. Santori and N. S. Lewis, Chem. Rev., 2010, 110, 6446-6473.
[2] I. Katsounaros, S. Cherevko, A. R. Zeradjanin, and K. J. J. Mayrhofer, Angew. Chem., Int. Ed., 2014, 53, 102-121.
[3] A. Ramírez, P. Hillebrand, D. Stellmach, M. M. May, P. Bogdanoff, and Sebastian Fiechter, J. Phys. Chem. C, 2014, 118 (26), 14073–14081.
[4] C. Toparli, A. Sarfraz, A. Erbe, Phys. Chem. Chem. Phys. 2015, 17, 31670-31679.
[5] C. Toparli, A. Sarfraz, A. D. Wieck, M. Rohwerder and A. Erbe, Electrochim. Acta, 2017, 236, 104–115.
(Invited) Hydrogen and Methylcyclohexane Production By Solar Water Splitting Using Photoelectrochemical Cells
Authors: Minegishi Tsutomu , Domen Kazunari 
Published: February 2020

Production of energy carriers through the solar water splitting have been attracted huge attentions as the key technology to construct a sustainable energy society. Hydrogen is the promising candidate for energy carrier because of its simple production through water splitting and utilization in many devices including fuel cells. On the other hand, Methylcyclohexane (MCH) is the promising hydrogen carrier because of its high hydrogen content per volume and usability of existing infrastructures. Herein, we investigated photoelectrochemical (PEC) hydrogen production from water and PEC MCH production through hydrogenation of toluen in existence of water as a hydrogen source.

For efficient PEC solar hydrogen and MCH production, utilization of photocatalytic materials with narrow bandgap energy is indispensable. The combination of a photoanode and a photocathode can relax the requirements for the photoelectrodes through the accumulation of driving forces.
The solid solution of ZnSe and Cu(In, Ga)Se2, ZnSex:CIGS1-x, shows relatively large cathodic photocurrent with high onset potential under simulated sunlight.1,2) The PEC cell composed of surface modified ZnSe-CIGS photocathode and BiVO4 photoanode could drive water splitting reaction with a solar-to-hydrogen conversion efficiency of hither than 1%. The PEC cell consisting of ZnSe-CIGS based membrane-photoelectrode assembly (MPA) and a BiVO4 photoanode also showed spontaneous conversion of toluene to MCH with water as a hydrogen source. In the presentation, the effects of surface modifications on durability and performance of the PEC cell for direct production of hydrogen and MCH will be discussed.

1) H. Kaneko, T. Minegishi, M. Nakabayashi, N. Shibata, Y. Kuang, T. Yamada, K. Domen, Adv. Func. Mater., 2016, 26, 4570-4577.

2) H. Kaneko, T. Minegishi, M. Nakabayashi, N. Shibata, K. Domen, Angew. Chem. Int. Ed., 2016, 55, 15329-15333.
(Invited) Semiconductor Photocathode Materials for Direct Solar Fuel Production
Authors: Sivula Kevin 
Published: February 2020

The development of robust and inexpensive semiconducting materials that operate at high efficiency are needed to make the direct solar-to-fuel energy conversion by photoelectrochemical cells economically viable. In this presentation our laboratory’s progress in the development new light absorbing materials as photocathodes will be discussed along with the application toward overall solar water splitting tandem cells for H2 production. Specifically, this talk will highlight recent results with the ternary oxide CuFeO2, 2D transition metal dichalcogenides, and organic (π-conjugated) semiconductors as solution-processed photoelectrodes.
With respect to CuFeO2, in our recent work [1] we demonstrate state-of-the-art sacrificial p-type photocurrent with optimized nanostructuring. Recent results addressing interfacial recombination by the electrochemical characterization of the surface states and attached co-catalysts will be presented along with approaches to overcome the limitations of this material.
In addition, two-dimensional (2-D) transition metal dichalcogenides (TMDs) generally have intriguing electronic properties making them promising candidates for high-efficiency solar energy conversion. However, it is notoriously difficult to fabricate thin films of 2-D TMDs over the large areas required to convert solar energy on a practical scale. We recently developed a simple method to fabricate high-quality thin films of 2-D layered TMDs at low cost and with good efficiency towards solar-to-fuel energy conversion [2]. The challenges with charge transport, separation [3] and water redox catalysis in these systems will also be discussed with respect to the 2D flake size.
Finally, with respect to π-conjugated organic semiconductors, in our recent work [4] we demonstrate a π-conjugated organic semiconductor for the sustained direct solar water oxidation reaction. Aspects of catalysis and charge-carrier separation/transport are discussed.
[1] Prevot, M. S.; Li, Y.; Guijarro, N.; Sivula, K. J. Mater. Chem. A
2016, 4, 3018-3026.
[2] Yu, X.; Prevot, M. S.; Guijarro, N.; Sivula, K., Nat. Commun. 2015, 6, 7596.
[3] Yu, X.; Rahmanudin, A.; Jeanbourquin, X. A.; Tsokkou, D.; Guijarro, N.; Banerji, N.; Sivula, K. ACS Energy Lett. 2017, 2, 524.
[4] Bornoz, P.; Prévot, M. S.; Yu, X.; Guijarro, N.; Sivula, K. J. Am. Chem. Soc. 2015, 137, 15338.
(Invited) Design of Plasmonic Catalysts Efficient H2 Production from Hydrogen Storage Molecules
Authors: Yamashita Hiromi , Mori Kohsuke , Kuwahara Yasutaka , Cheng Hefeng , Wen Meicheng , Verma Priyanka , Yin Haibo 
Published: February 2020

Nanostructured plasmonic noble metals such as Au and Ag are attractive materials that strongly absorb visible light owing to their localized surface plasmon resonance (LSPR). [1-6] Up to now, the search for efficient and safe hydrogen storage materials is of crucial significance. Ammonia borane (AB: NH3BH3) and formic acid (FA) with high hydrogen content are attractive chemical hydrogen storage candidates. In this study, we demonstrated that the plasmonic nanostructures, including color-controlled Ag nanoparticles (NPs), novel MoO3-x nanosheets, and core-shell Au@Pd NPs on Metal organic frameworks (MOFs) was used as efficient catalysts under visible light for H2production from these hydrogen storage molecules.
The Ag NPs were prepared on SBA-15 mesoporous silica by microwave-assisted alcohol reduction in the presence or absence of sodium laurate. MoO3-x nanosheets were prepared by oxidizing metal molybdenum powders with H2O2 followed by the solvothermal treatments in ethanol. The catalytic performances were investigated for dehydrogenation of AB in aqueous suspensions with plasmonic catalysts. The activity for H2 production was greatly enhanced by the visible light irradiation induced by LSPR specially on the rod type Ag NPs with lager aspect ratio. Plasmonic semiconductors is another novel category with low resistive loss and earth abundance. By a facile nonaqueous access, MoO3-x nanosheets with tunable LSPR from visible light to near infrared were prepared. Under visible light irradiation, such plasmonic MoO3-x nanosheets displayed dramatically enhanced H2 production rate from AB. Furthermore, a synergistic catalysis of plasmonic Au@Pd NPs supported on titanium doped zirconium based amine-functionalized MOF(UiO-66(Zr100-xTix)) was observed for boosting H2 production from FA. The electronically promoted Pd by the charge transfer arising from the difference in work function of Pd and Au metals and the LSPR effect of Au play a crucial role in achieving high catalytic activity for H2production from FA.
1) P. Verma, Y. Kuwahara, K. Mori, H. Yamashita, Chem. Eur. J., 23, 3616 (2017). [Front Cover]
2) M. Wen, K. Mori, Y. Kuwahara, H. Yamashita, ACS Energy Lett.
2, 1 (2017.)
3) H. Cheng, M. Wen, Y. Kuwahara, K. Mori, Y. Dai, B. Huang, H. Yamashita, J. Am. Chem. Soc., 138, 9316 (2016). [Featured in JACS Spotlights]
4) P. Verma, Y. Kuwahara, K. Mori, H. Yamashita, J. Mater. Chem. A, 4, 10142 (2016). [Front cover]
5) H. Cheng, T. Kamegawa, K. Mori, H. Yamashita, Angew. Chem. Int. Ed., 53, 2910 (2014).
6) K. Fuku, T. Kamegawa, K. Mori, H. Yamashita, Angew. Chem. Int. Ed., 52, 7446 (2013).

Figure 1
Combustion Synthesis and Photoelectrochemical Characterization of Metal Oxynitrides Using GaxZn1-XOyN1-Y as a Model Candidate
Authors: Meekins Benjamin Highsmith 
Published: February 2020

Utilization of solar energy is a necessary path forward to deal with the looming energy crisis and worldwide effects of fossil fuel usage. A key component of this utilization is how to store excess solar energy for use on demand. One such method is splitting water into hydrogen and oxygen, both of which can be stored and either burned as fuel or used as feedstock components in industrial processes to synthesize high-value materials. Metal oxynitrides have shown great potential as photocatalysts for overall water splitting applications. Incorporation of nitrogen into metal oxides narrows the band gap to enable absorption of light in the visible spectrum. The typical synthesis of a metal oxynitride, however, requires annealing temperatures at or above 1000 oC and nitridation by flowing pure ammonia gas for anywhere from 1 to 48 hours. Such harsh synthesis conditions can limit the discovery of new candidate materials.
In our work, we have prepared an array of gallium zinc oxynitrides (GaxZn1-xOyN1-y) as a model system using a combustion synthesis method and demonstrate that gallium zinc oxynitrides can be synthesized in 30 minutes at 500 oC using this method. X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) are used to characterize the physical properties of the as-synthesized materials. XPS analysis reveals that as much as 50% nitrogen substitution in the metal oxide lattice can be achieved, dependent on the ratio of gallium and zinc nitrates used as precursors. XPS also reveals that the nitrogen valency is that of a nitride material, as would be expected for a substitution into the crystal lattice. Relative atomic concentrations from XPS also reveals that the complex formed is essentially GaN:ZnO. UV-visible spectroscopy reveals that the band gap of the GaxZn1-xOyN1-ymaterials can be controlled simply by altering the precursor ratio. X-ray diffraction measurements reveal shifts in the crystalline peaks from ZnO toward GaN, confirming the incorporation of nitrogen into the lattice. The as-synthesized products are capable of generating photocurrent from visible light irradiation and are able to carry out water splitting in pure water without any co-catalysts, such as Pt, IrO2, or Rh/Cr2O3.
Finally, we discuss how to take the results gained from this work and expound upon it to begin the search for new candidate oxynitride materials, including potential high-throughput methods for rapid screening of such candidates. We also discuss the apparent conditions necessary for successful formation of an oxynitride material based on initial experiments with new candidates.
Figure caption: Picture of as-synthesized powders from an initial Ga:Zn:urea molar ratio of (A) 1:1:0 and (B) 1:1:10.

Figure 1
(Keynote) Ionic Liquid-Based Electrolytes for Alkali Metal Batteries
Authors: Moretti Arianna , Passerini Stefano 
Published: February 2020

Li-metal batteries have known a continuous development since the introduction of PEO based electrolytes [1]. The coming on the market in 2012 of a Li-metal polymer powered car with 250 km driving range (BlueCar) has confirmed the possibility to implement lithium metal batteries in the market. Moreover, most of the ‘next generation’ batteries such as Li-S or Li-air are based on Li-metal negative electrodes. If the present Li-metal electrolytes are based on polymer electrolytes, ionic liquids (ILs) based electrolytes such as LiFSI-PYR14FSI [2] or crosslinked PEO-PYR14TFSI-LiTFSI [3] have demonstrated very reversible lithium plating/stripping.
IL-based electrolytes are also showing promising performance in novel energy storage systems such as Na/seawater batteries [4].
A review of our results on the use of ionic liquid-based electrolytes for lithium, sodium, and multivalent cations will be presented.

Acknowledgement:

This work is supported by the European Commission within the projects LABOHR and INFLUENCE and the Helmholtz Gemeinschaft within the project “Helmholtz-Energie-Allianz - Stationaere elektrochemische Feststoff -Speicher und –Wandler” (HA-E-0002).

References :

1. M. Armand, M. Duclot, J. M. Chabagno, EU 00013199
2. E. Paillard, Q. Zhou, W. A. Henderson, G. B. Appetecchi, M. Montanino and S.Passerini,

J. Electrochem. Soc.
156 (11) (2009) 891-895
3. G.T. Kim, G.B. Appetecchi, M. Carewska, M. Joost, A. Balducci, M. Winter, S. Passerini,
J. Power Sources
195 (2010) 6130–6137
4. J.-K. Kim et al,
NPG Asia Materials
6 (2014) e144.
Synthesis of Nanoscale Li7La3Zr2O12 Solid State Electrolyte By Spray Drying
Authors: Uddin Md-Jamal , Letfullina Alla R , Alaboina Pankaj Kumar , Cho Jong-Soo , Cho Sung-Jin 
Published: February 2020

To enable the futuristic applications of Li-ion batteries, significant boost in energy density and tremendous improvement in safety is required. Ceramic solid state electrolytes (SSE) with fast Li-ion diffusion are a promising class of materials that can potentially change the scenario because of their superior thermal and chemical stabilities and a wider operational temperature window. Among the numerous different solid-state oxide materials, Li7La3Zr2O12(LLZO) has gained significant interest due to its high ionic conductivity, good compatibility with lithium metal and stability in air. The preparation of LLZO is mostly based on the conventional solid state syntheses or sol-gel method, in which powders are calcined usually at temperatures above 850 °C. These current synthesis routes generally require higher calcination temperatures and longer heating duration.
In this work, we have reported spray-dried LLZO particles for the first time via a low-temperature calcination. Spray drying has allowed us to achieve a nanoporous LLZO precursor which was later calcined only at 450 °C for 4 hours to obtain the LLZO particles. The nanoporous spray-dried particles have aided in the sintering process because of higher surface energy, and thus has significantly reduced the calcination time and temperature. LLZO Pellets were prepared for further physical-chemical characterization. Electrochemical performance evaluation is also in order.
Structure-Property-Process Relationships of Melt-Blown PVDF: A Potential Li-Ion Battery Separator
Authors: Luiso Salvatore , Fedkiw Peter S , Spontak Richard J , Pourdeyhimi Behnam 
Published: February 2020

While significant research efforts have focused on the negative and positive electrode materials in rechargeable Lithium-ion (Li-ion) batteries, battery separators have only recently received more consideration from the scientific community. The separator plays a critical role in Li-ion batteries by preventing physical contact between the positive and negative electrodes while permitting efficient ionic transport across the separator. There are four major types of separators: microporous polymeric membranes, nonwoven polymeric mats, gel-polymer electrolytes and composite membranes. Relative to the more conventional microporous membrane separators, nonwovens have the advantage of low cost, low mass and high porosity; in addition, the fibrous mat provides good structural cohesion due to its intertwined fibers. Although most polymers used to make nonwoven battery separators have resulted in lower cell performance (lower ionic conductivity and higher resistance) than conventional microporous separators, polyvinylidene difluoride (PVDF) shows promising results because of its stability and affinity for electrolytes commonly employed in Li-ion cells. The best manner to produce nonwoven PVDF would employ a melt-blowing process, which is a well-developed, high-volume production technology. To be melt-blowable, polymer resins must have high melt-flow rates but commercial PVDF resins did not possess this property until recently. Nevertheless, researchers have successfully electrospun PVDF from a solution with the goal of exploring this promising polymer as a nonwoven battery separator.
We are investigating the fundamental properties and characteristics of two novel melt-blowable PVDF grades (Kynar® 705 and Kynar® ADS II from Arkema) with the objective of elucidating their structure-property-process relationships and studying their performance as separators in Li-ion batteries. In this work, we will report on the physical, chemical, and electrochemical properties of nonwoven PVDF relevant to their use as battery separators.