bluuebunny/crossref_metadata_2025_split huggingface dataset:
3D-Nanostructures-Path to High Capacity Lithium Batteries
Authors: Prochazka Jan 
Published: February 2020

Thin film technology (2D) producing lithium ion accumulators has nearly been optimized. The capacity limits are given by the thickness of the components, especialy the foils and separators.
It has been demonstrated that a significant increase of lithium battery capacity is achievable by nanostructured morphologies of the electrodes and extending of the electrode thickness from micrometers (2D) to millimeters (3D).
The HE3DA®batteries based on several millimeters thick electrodes is ideal for high capacity micro batteries and large energy storage modules.
Optimizing Electrolyte Formulations for Better Lithium-Ion Batteries
Authors: Abu-Lebdeh Yaser 
Published: February 2020

In this presentation different electrolyte formulations that can improve the performance of current Li-ion batteries will be discussed. One is based on the idea of mixing ionic liquids with carbonate solvents in order to combine the advantages of the two and achieve thermally stable and nonflammable electrolyte mixtures with good cycling performance.
Another is based on aliphatic dinitriles solvents, NC-(CH2)n-CN, n = 3-8, that show good thermal and electrochemical stability (6-8 V). The variation in physical properties, crystallographic structure and battery performance of the different dinitrile-based electrolytes will be discussed.
Also, the use of these electrolyte formulations for high voltage batteries with the 4.7 V cathode material LiNi0.5Mn1.5O4 will be discussed in details.
[1] Y. Abu-Lebdeh and I. Davidson, J. Electrochem. Soc. 2009, 156 A60; J. Power Sources 2009, 189 576
[2] H. Duncan, N. Salem, Y. Abu-Lebdeh, J. Electrochem. Soc.2013, 160 A838
Digging into Electrolyte Interactions—Challenging the Conventional Wisdom
Authors: Henderson Wesley , Seo Daniel M. , Han Sang-Don , Allen Joshua L. , Yun Sung-Hyun , Daubert James S. , Borodin Oleg 
Published: February 2020

The utilization of electrolytes for lithium batteries is linked with a significant body of conventional wisdom about electrolytes based largely upon assumptions—unfortunately, many of these assumptions are inaccurate. The misconstrual of the analysis of experimental data often leads to highly erroneous interpretations of electrolyte interactions. The resulting poor understanding of the molecular- and mesoscale-level solution structure of electrolytes is highly restrictive for the tailoring of new electrolyte formulations for advanced battery chemistries.
This talk will discuss the utility (or lack thereof) of solvent polarization parameters (e.g., dielectric constant (ε), Gutmann donor number (DN), etc.) for determining the strength of solvation interactions with Li+ cations, the challenges associated with using Raman spectroscopy to obtain accurate Li+cation solvation numbers and determine the solvate species present in solution, how the strength of the ionic association interactions is uncorrelated with salt solubility and how Walden plots are poorly suited for characterizing the ionic association characteristics of electrolytes. The invaluable information which may be gleaned from the fusion of experimental and computational (Fig. 1) methods will be emphasized to provide a rigorous discourse on both the phase behavior and properties of dilute electrolytes, as well as highly concentrated (> 5M ) electrolytes.

Figure 1. Snapshot of a MD simulation of a (AN)n-LiBF4mixture (n = 10 or 1.7M): (top) original MD simulation box and (bottom) same MD simulation box with the uncoordinated acetonitrile (AN) molecules colored gray and the solvates grown across the periodic boundaries (Li-purple, B-tan, F-light green).

ACKNOWLEDGEMENT

The authors wish to express their gratitude to the U.S. Department of Energy (DOE) Office of Basic Energy Science-Division of Materials Sciences and Engineering and the Vehicle Technologies Program which supported the experimental research under awards DE-SC0002169 and DE-AC02-05-CH11231.
A New Family of Anion-Binding-Agent (ABA) Based Stable Salts for Li and Li-Ion Batteries
Authors: Nagasubramanian Ganesan , Orendorff Christopher J. , Fenton Kyle R 
Published: February 2020

Introduction:

Thermal instability of LiPF6 at elevated temperatures is well known. Thus there is an imminent need to develop thermally stable salt to replace LiPF6. A variety of new salts have been studied in Li-ion batteries without much success. One of the salts we are currently evaluating is LiF. This is a low molecular weight salt that has high voltage and thermal stability. However, it doesn’t dissolve in common battery solvents. This limitation can be solved with the addition of anion binding agents (ABAs). For example, Mehta and Fujinami1 proposed boroxine (tri coordinate boron ring) which is a Lewis Acid, to solubilize salt in common battery electrolyte. This compound traps the anion of the salt and frees up the Li+ for conduction. A similar idea was developed by McBreen etal
2-4 where they synthesized boron containing additives to dissolve LiF in organic solvents. However, most of the ABAs investigated are heavy with molecular weight exceeding 500 g/mole. Bulky ABAs impede access of the anion of the salt to the binding site (boron center) thus leading to poor dissolution of the salt5, 6.
Inspired by McBreen’s approach we launched a program and developed lower molecular weight (~250 g/mole) ABAs. We quickly learned that the as prepared ABAs do have DMSO solvent bound to the boron (this is designated as impure ABA). We purified the impure ABA by reacting with LiF in acetone which yielded a pure ABA+LiF salt. The purified salt gave a clear solution whereas the impure ABA+LiF salt gave a cloudy solution in EC:EMC (Photo-1).
We have prepared a variety of ABAs and tested them for electrochemical performance. Most of them could solubilize LiF only poorly and showed very low conductivity. However, two of the ABAs are promising and the results on one of them will be described here.

Electrochemical Performance:

Figure 2 compares conductivity for the pure and impure Oxalic-ABA+LiF in EC:EMC
We have prepared a variety of ABAs and tested them for electrochemical performance. Most of them could solubilize LiF only poorly and showed very low conductivity. However, two of the ABAs are promising and the results on one of them will be described here.

Electrochemical Performance:

Figure 2 compares conductivity for the pure and impure Oxalic-ABA+LiF in EC:EMC solvent blend at different temperatures. The pure ABA shows higher conductivity than the impure.
Electrochemical measurements and cell building was performed with the purified salt. This showed stability up to 4.5V vs. Li+/Li but unstable close to Li voltage, which was eliminated by adding low concentration of LiPF6 to the solution.
Figure 3 shows formation of an 18650 cell containing carbon anode, NMC (523) cathode in EC:EMC(3:7 w%)-ABA+LiF_10mM LiPF6. The reversible capacity is ~ 1.03Ahrs.
Synthesis and Characterization of Poly (ethylene glycol) Methacrylate with Sulfobetaine Pendants and Its Application as the Polymer Electrolyte
Authors: Cardoso Judith , Guzman Gregorio , Nava Dora , González I. 
Published: February 2020

In the design of a lithium-ion battery, it is important the electrolyte and the polymer support. Some polyampholytes, in which both cation and anion are fixed in the polymer main chain, have showed to have a low glass transition temperature and be able to solve any kind of salts [1]. In this work, the synthesis of a methacrylate polymer, with sulphobetaine and eight etoxy residues in the side chain (PMBS-8 see Figure 1, structure 4)) was carried out to investigate the feasibility of its use as a polymer electrolyte in lithium batteries. FTIR, and 1H NMR demonstrate that the synthesis method achieves 90% functionalization. XRD spectra shows that PMBS-8 is able to dissolve LiPF6 in 1:1 (PMBS-8/ LiPF6) molar ratio. In order to improve charge transport properties and mechanical, it has been proposed the addition of non-flammable, non-volatile, room temperature ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, PYR11TFSI).
The parent polymer, is used to prepare electrolytes: polymer (PMBS-8) /LiPF6 and PMBS-8/LiPF6 / Ionic liquid (PYR11TFSI) as plasticizer. The resulting electrolyte polymers show mechanical properties akin to elastic solids. The glass transition temperature is closed at 14 °C for all specimens, and PMBS-8 is thermally stable up to 195 °C which is important since thermally stable polymers along a wide temperature range are sought for this kind of application. The conductivity of these materials which was dried carefully, varies with temperature, following an Arrhenius-like relationship. The maximum conductivity has been found to be 4.3×10−
4 S cm−
1 at room temperature for electrolyte (PMBS-8/LiPF6/PYR11TFSI).
References.
[1] J. Cardoso, G. Vazquez, I. González J. Phys Chem C, 2010, 114, 14261.
Plasmon-Enhanced Photocatalysis on TiO2-Passivated Gallium Phosphide
Authors: Cronin Stephen B. 
Published: February 2020

Integrating plasmon resonant nanostructures with photocatalytic semiconductors shows great promise for highly efficient photocatalytic processes1-4. However, the electrochemical instability of most III-V semiconductors severely limits their applicability in photocatlaysis. In this work, we passivate p-type GaP with a thin layer of n-type TiO2 using atomic layer deposition. The TiO2 passivation layer prevents corrosion of the GaP, as evidenced by atomic force microscopy and photoelectrochemical measurements. In addition, the TiO2 passivation layer provides an enhancement in photoconversion efficiency through the formation of a charge separating pn-region. Plasmonic Au nanoparticles deposited on top of the TiO2-passivated GaP further increases the photoconversion efficiency through local field enhancement. These two enhancement mechanisms are separated by systematically varying the thickness of the TiO2 layer. Because of the tradeoff between the quickly decaying plasmonic fields and the formation of the pn-charge separation region, an optimum performance is achieved for a TiO2 thickness of 0.5nm. Finite difference time domain (FDTD) simulations of the electric field profiles in this photocatalytic heterostructure corroborate these results. The effects of plasmonic enhancement are distinguished from the natural catalytic properties of Au by evaluating similar photocatalytic TiO2/GaP structures with catalytic, non-plasmonic metals (i.e., Pt) instead of Au. This general approach of passivating narrower band gap semiconductors enables a wider range of materials to be considered for plasmon-enhanced photocatalysis for high efficiency water splitting.
1 Qiu, J., G. Zeng, P. Pavaskar, Z. Li and S.B. Cronin, Plasmon-Enhanced Water Splitting on TiO2-Passivated GaP Photocatalysts. Physical Chemistry Chemical Physics, 16, 3115 (2014).
2 Hung, W.H., M. Aykol, D. Valley, W.B. Hou and S.B. Cronin, Plasmon Resonant Enhancement of Carbon Monoxide Catalysis. Nano Letters, 10, 1314-1318 (2010).
3 Hou, W., Z. Liu, P. Pavaskar, W.H. Hung and S.B. Cronin, Plasmonic Enhancement of Photocatalytic Decomposition of Methyl Orange under Visible Light. J. Catal., 277, 149 (2011).
4 Liu, Z., W. Hou, P. Pavaskar, M. Aykol and S. Cronin, Plasmon Resonant Enhancement of Photocatalytic Water Splitting Under Visible Illumination. Nano Letters, 11, 1111 (2011).
Plasmonic Solar Fuels Based on Nanostructured Oxide Photocatalysts
Authors: KIM Dong Ha , Jang Yoon Hee , Kochuveedu Saji Thomas , Quan Li Na 
Published: February 2020

Solar energy can be directly converted to electrical energy via photovoltaic devices. Photocatalysis provides an alternative route to the conversion of solar energy that can be stored in chemical fuels through photoelectrochemical cells or particulate photocatalytic systems. While a number of strategies were developed to overcome the deficiencies of existing semiconductors, incorporation of plasmonic nanostructures with semiconductors has gained increasing attention as a promising paradigm to improve the solar energy conversion efficiency. In this presentation, we introduce diverse approaches for the fabrication of nanostructured semiconductors integrated with plasmonic structures that can be exploited to exhibit enhanced photo-conversion efficiencies.
First, a surface plasmon (SP) induced visible light active photocatalyst system composed of silica-titania core-shell (SiO2@TiO2) nanostructures decorated with Au nanoparticles (Au NPs) was developed. The influence of size and distribution of Au NPs on photocatalysis, its fabrication methods and exploration of the mechanism of visible light activity were investigated. A favorable architecture of SiO2 beads with a thin layer of TiO2 was decorated with Au NP arrays having different size and areal density. Surface modification of SiO2@TiO2 leads to a viable and homogenous loading of Au NPs on the surface of TiO2, which renders visible light-induced photocatalytic activity on the whole TiO2 surface. An optimized system employing Au NP arrays with 15 nm size and 700/µm2 density showed best catalytic efficiency, due to a synergistic effect of the firm contact between Au NPs and TiO2 and efficiently coupled SPR excitation. A brief mechanism relating the electron transfer from surface plasmon stimulated Au NPs to the conduction band of TiO2 is proposed. The same system was further tailor-modified to exhibit far-field scattering effect, to lead to maximized performance toward solar water splitting.
Next, we focus on our design principle for the plasmon-enhanced oxide-based photocatalytic systems based on inverse opal structures and demonstrate the SP coupling effect on the efficiency of water splitting. Inverse opals of representative semiconductor oxide photocatalysts were fabricated by well-known colloid templating, and the surface was decorated with Au NPs. The effect of size and areal density of Au NP arrays were explored in terms of oxidation reactions and plasmon-enhancement effect was supported by FDTD analysis. An advance strategy to improve the efficiency of solar fuel generation includes the combined block-copolymer-based self-assembly, leading to hierarchically organized inverse opals with tailored surface area and nano-textured surface morphology. Further, we show that carbon-doped analogue inverse opal structures could be readily obtained by direct carbonization of block copolymer templates, based on which simultaneous carbon-doping and plasmon-enhancement effect are synergistically realized.
Controlling the Selectivity of the CO2 Electrochemical Reduction through Anion Effects
Authors: Varela Ana Sofia , Reske Rulle , Strasser Peter 
Published: February 2020

Despite over two decades of research on the CO2 electrochemical reduction the selectivity and the energy efficiency of this reaction still need to be improved. A better understanding of the factors that influence this reaction is crucial in the designing new and more efficient catalyst.
Recently, Salazar-Villalpando and co-workers have suggested that the presence of halides in the solution can facilitate the reduction of CO2 on copper. This conclusion, however, is based only the reduction currents and the reaction products were not analyzed.
In the present work we have performed CO2 electrolysis, in KHCO3 in the presence of halides (Cl-, Br-, I-). Interestingly, we observed that besides the positive effect that the presence of halides has in the reduction activity, there is also a clear effect on the selectivity of the reaction.
On copper, the efficiency towards hydrocarbons is enhancedby the presence of bromide and iodine. Remarkably, the ratio between methane and ethylene depends on which halide is in solution. In the presence of Cl- and I- both methane and ethylene are formed. By contrast, when bromide is added to the electrolyte ethylene formation is the completely suppressed and methane is the predominant product from the CO2 electrochemical reduction.
These results indicate that halides affect differently the reaction paths for methane and ethylene. Understanding this difference could be key in the overall understanding on the reaction mechanism to C2 products which is still on debate.
Fabrication of Transition Metal Doped TiO2 Photocatlyst for Artificial Photosynthesis Applications
Authors: Abidov Amir , Allabergenov Bunyod , Xiao Feiyi , Jin Xing , Jeong Soon-Wook , Kim Sungjin 
Published: February 2020

Elimination of greenhouse gases from atmosphere became an ultimate problem recently. Previously we reported of formic acid photosynthesis using Iron doped TiO2 [1]. In this paper we discuss various transition metal doped TiO2 for artificial photosynthesis application. Powder TiO2 was doped using transition metal. Photocatalyst was characterized by X-ray diffractometry, X-ray photoelectron spectroscopy and Field Emission Scanning Electron Microscope. Prepared photocatalyst was used for photosynthesizing of carbonyl and amino compounds from CO2 gas and nitric acid. Prepared samples were examined using UV-visible spectroscopy, Infrared spectroscopy and gas chromatography. Selectivity of prepared catalyst to alcohols, formates and ureas was compared and discussed. It was found that transition metal doped TiO2 is much more efficient for photosynthesis purpose than bare one.
References:
[1] Amir Abidov et al., 2013, Applied Mechanics and Materials, 479-480, 100
Energy Payback Time Modeling of Integrated Photoelectrochemical Devices Using Concentrated Solar Irradiation
Authors: Dumortier Mikael , Haussener Sophia 
Published: February 2020

The photoelectrochemical (PEC) production of hydrogen offers a direct pathway for the conversion of solar energy into an energy dense and transportable fuel. In an integrated PEC device, solar radiation is absorbed by photoactive components which provide the necessary potential for water electrolysis to take place in the integrated proton exchange membrane electrolysis cell (PEMEC). The produced current density in the photovoltaic component (PV) increases with increasing solar irradiation, i.e. concentration. This results in higher hydrogen production rates for a PEMEC with small overpotentials, i.e. good ohmic conductors and efficient catalysts, compared to non-concentrating systems. We also expect further reduction in energy and material requirements of a concentrated PEC (CPEC) device and its fabrication and, consequently, its energy payback time (EPBT). We compared the EPBT of PEC and CPEC devices for water electrolysis. For the latter, we compared existing concentrating technologies - lenses, mirrors, and Cassegrain reflectors - and a novel integrated CPEC device using a self-tracking wave-guide concentrator.
We developed a model that assesses the energy requirements of the different component (concentrator, electrolysis cell, photovoltaic cell, external components) by coupling the energy and material inventory of devices to a detailed performance model under different concentrations. The model uses the Shockley-Queisser limit to assess the performance of the multijunction photovoltaic cell, and an equivalent circuit model was used to assess the performance of the electrolysis cell, including kinetic overpotentials via Butler-Volmer expressions, ohmic resistances via Ohm’s law, and mass transport overpotentials [1].
The results show that the EPBT of all concentrating technologies are in the same order of magnitude (5-10 years). However, the integrated self-tracking concentrator design shows a lower EPBT than Fresnel lenses-based concentrating systems due to a lower primary energy demand of the former (1600 MJ/m² for integrated, self-tracking concentrator, and 2800 MJ/m² for external Fresnel concentrator coupled to PV-electrolyzer). A sensitivity analysis showed that the most influential parameters for the reduction of the EPBT are the yearly solar irradiation, the primary and operating energy demand of the concentrator, the performance of the concentrator, the exchange current density of the catalysts, and the fill factor of the photovoltaic cell. The EPBT could be reduced by at least 6% with a variation of 10% of one of these parameters for all the technologies studied.
This developed model provides a useful tool for device design to compare and optimize the energy requirements of integrated PEC and CPEC devices
[1] P. K. Das, X. Li, and Z.-S. Liu, “Analytical approach to polymer electrolyte membrane fuel cell performance and optimization,” J. Electroanal.
Chem., vol. 604, no. 2, pp. 72–90, Jun. 2007.
In Situ Localized Current Distribution in a Vanadium Redox Flow Battery
Authors: Clement Jason T. , Zawodzinski Thomas A. , Mench Matthew M. 
Published: February 2020

Significant development of redox flow battery (RFB) technology has taken place recently to assess their viability as a large-scale energy storage system1. Such systems have been implemented in select instances to demonstrate their feasibility; however there is still a lack of fundamental understanding regarding these devices. Of the numerous possible redox couples, the all-vanadium chemistry is the most commonly studied RFB. With the extensive literature available regarding this chemistry, there is still a lack of available diagnostic techniques to provide distributed measurements for understanding fundamental mechanisms within these cells.
The use of a printed circuit board in electrochemical cells provides a useful distributed diagnostic as demonstrated by its extensive use in fuel cells2. The application of this technology to measure in-plane current distribution in a RFB has been previously demonstrated as shown in Figure 1.3This work will build upon that foundation to gain further insight regarding the influence of cell architecture and operating conditions on distribution.

References

1. A.Z. Weber, M.M. Mench, J.P. Meyers, P.N. Ross, J.T. Gostick, Q. Liu, J. Appl. Electrochem., 41, 1137, (2011).
2. J.J. Gagliardo, J.P. Owejan, T.A. Trabold, T.W. Tighe, Nucl. Instruments Methods Phys. Res. Sect. A Accel. Spectrometers, Detect. Assoc. Equip., 605, 115, (2009).
3. J.T. Clement, T.A. Zawodzinski, M.M. Mench, 224th ECS Meet., San Francisco, CA, Oct. 27 – Nov. 1, 2013.

Figure 1. In-plane current distribution for a 9 cm2 vanadium RFB under 100 mA/cm2 discharge conditions.