bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fast Ion Conducting Solid-State Electrolytes for Sodium Ion Batteries — from Elementary Steps to Macroscopic Transport
Authors: Lunghammer Sarah , Wilkening Martin 
Published: February 2020

All-solid-state batteries and especially solid electrolytes stand in the spotlight of current energy research.[1,2] An extremely high ion mobility, which is known for liquid electrolytes, is needed to realize batteries with ceramic electrolytes. Apart from Li-bearing materials also a range of sodium compounds exhibit extremely high ion conductivities. With regard to availability and costs Na-based energy storage systems have attracted great interest over the last years.[3]

Here we re-investigated the most prominent representatives of this kind of functional materials viz. Na-β''-alumina[4] and Na3Zr2(SiO4)2PO4 (NASICON), which are known to show conductivity values in the order of mS/cm at RT.[5,6] We used high precision impedance measurements and nuclear magnetic resonance (NMR) spectroscopy to study the diffusion mechanisms and long-range ion transport. In the case of Na-β''-alumina we focused on a commercially available sintered pellets to investigate both bulk dynamics and grain boundary effects on ionic conductivity. Impedance spectroscopy was helpful to interpret ion dynamics revealed by NMR on both short as well as long-range length scales. For well-sintered and highly dense samples ion transport across grain boundaries has only little impact on the overall fast ion transport seen.

References:

[1] J.C. Bachman, S. Muy et al., Chem. Rev.
2016, 116, 140-162.
[2] J. Janek, W. Zeier, Nature Energy 1

2016, 16141.
[3] B. L. Ellis, L. F. Nazar, Curr. Opin. Solid State Mater. Sci.
2012, 16, 168-177.
[4] M. Bettman, C. R. Peters, J. Phys. Chem.
1969, 73, 1774-1780.
[5] W. Jakubowski, D. H. Whitmore, J. Am. Chem. Soc.
1979, 62, 381-385.
[6] J. Goodenough, H.-P. Hong et al., Mat. Res. Bull.
1976, 11, 203-220.
Organic Electrolyte Dependent Electrochemical Performance of Lithium metal anode Materials for Lithium-Metal Batteries
Authors: Lee Da-Yeon , Kim Seong In , Park Geun-gyung , Eom Ji-Yong 
Published: February 2020

Lithium metal is the most attractive anode material for batteries because of its high specific capacity and low negative potential. However, lithium dendrite growth during lithium deposition leads to serious safety problems and poor cycling performance.
According to the previous reports, the electrochemical performance of lithium metal anode material for LIBs highly depends on the composition and physicochemical properties of the electrolytes used. However, a key factor with regard to electrolytes that can determine the electrochemical characteristics of the anode materials is not fully understood yet.
Thus, in the present work, we observed the electrochemical performance of lithium metal anode material as a function of electrolyte parameters, and elucidated the chemical/electrochemical reaction behavior of various electrolytes on the surface of lithium metal.
Thiadiazoles As Anolytes for Nonaqueous Redox Flow Cells
Authors: Huang Jinhua , Duan Wentao , Zhang Jingjing , Shkrob Ilya A , Assary Rajeev , Wei Xiaoliang , Zhang Lu 
Published: February 2020

Understanding structure-property relations is essential for designing energy-rich redox active materials (ROMs) for all-organic redox flow batteries.1-2 Herein we examine thiadiazole ROMs for storage of negative charge in the flow cells.3 These versatile molecules have excellent solubility and low redox potentials, allowing to achieve high energy density. By systematically incorporating groups with varying electron accepting/withdrawing ability, we have examined substituent effects on their properties of interest, including redox potentials, calendar lives of charged ROMs in electrolyte, and the flow cell cycling performance. While the calendar life of energized fluids can be tuned in a predictable fashion over a wide range, the improvements in the calendar life do not automatically translate into the enhanced cycling performance, indicating that in addition to the slow reactions of charges species in the solvent bulk, there are other parasitic reactions that occur only during electrochemical cycling of the cell and can dramatically affect the cycling lifetime. This finding strongly indicates the significant role of structural engineering in achieving improvement of radical ion stability, suggesting a generic guidance for developing long-cycling ROM-based flow cells. With these molecules we are on the very edge of possibility, reaching the compromise between the highest energy density and the stability of the radical anion that can be achieved in acetonitrile. We believe that setting these limits is more important for the energy storage community than surveying of different classes of the anolytes.
Figure 1 Structures and cyclic voltammogram of benzothiadiazole derivatives and the correlation of the half-decay lifetime of the radical anions with the redox potentials. Mind the logarithmic vertical scale.

Zhang, J.; Yang, Z.; Shkrob, I. A.; Assary, R. S.; Tung, S. o.; Silcox, B.; Duan, W.; Zhang, J.; Su, C. C.; Hu, B.; Pan, B.; Liao, C.; Zhang, Z.; Wang, W.; Curtiss, L. A.; Thompson, L. T.; Wei, X.; Zhang, L., Annulated Dialkoxybenzenes as Catholyte Materials for Non-aqueous Redox Flow Batteries: Achieving High Chemical Stability through Bicyclic Substitution. Advanced Energy Materials
2017,
7 (21), 1701272-n/a.

Zhang, L.; Zhang, Z.; Redfern, P. C.; Curtiss, L. A.; Amine, K., Molecular engineering towards safer lithium-ion batteries: a highly stable and compatible redox shuttle for overcharge protection. Energy & Environmental Science
2012,
5 (8), 8204-8207.

Duan, W.; Huang, J.; Kowalski, J. A.; Shkrob, I. A.; Vijayakumar, M.; Walter, E.; Pan, B.; Yang, Z.; Milshtein, J. D.; Li, B.; Liao, C.; Zhang, Z.; Wang, W.; Liu, J.; Moore, J. S.; Brushett, F. R.; Zhang, L.; Wei, X., “Wine-Dark Sea” in an Organic Flow Battery: Storing Negative Charge in 2,1,3-Benzothiadiazole Radicals Leads to Improved Cyclability. ACS Energy Letters
2017,
2 (5), 1156-1161.

Figure 1
Artificial Solid-Electrolyte Interphase Layer for Improved Electrochemical Window of Magnesium Ion Batteries
Authors: Nishitani Yu , Tsujita Takuji 
Published: February 2020

As a type of next-generation secondary batteries, the magnesium ion battery achieves high energy capacity by using metal magnesium anodes. However, stable battery operation has only been confirmed when using a metal sulfide cathode [1], whose energy capacity and operating potential are lower than those of the latest lithium ion batteries.
One way to increase the output voltage is establishing a cathode / electrolyte interface that is compatible with the cathode redox reaction at a higher potential, where the liquid electrolyte is subjected to oxidization. To accomplish this, a solid-state electrolyte on the thin film cathode could be used to suppress the oxidative decomposition of liquid electrolyte in the magnesium battery. Since the electronically insulating solid state electrolyte inhibits the unwanted electron transfer between the cathode and the electrolyte solution, the electrochemical potential window of the liquid electrolyte could be widened. This solid-state electrolyte coating may be regarded as an artificial solid-electrolyte interphase (ASEI) [2]. We prepared a cell with V2O5 thin film cathode coated by a MgZrSiO amorphous solid-state electrolyte using RF sputtering technique. As a result, the cell had higher oxidative stability (decomposition at 4.5 V vs Mg2+/Mg) than the cell with the uncoated cathode (3.3 V vs Mg2+/Mg) (Figure 1).
Reference
[1] D. Aurbach, Nature, 407, 724 (2000).
[2] N. J. Dudney, J. Power Sources, 89, 176 (2000).
Figure 1 The cyclic voltammogram of the MgZrSiO-coated and bare V2O5 thin film cathodes in 0.5M Mg(TFSA)2/triglyme at 55℃. The scanning rate was 0.1 mV/s.

Figure 1
Molecular-Scale Insights of Aluminum-Ion Intercalation into Chevrel Phase Mo6S8
Authors: Jadhav Ankur , Messinger Robert J. 
Published: February 2020

Rechargeable aluminum batteries are a promising alternative to lithium-ion batteries due to the high volumetric energy density (8040 mAh/cm3), high abundance in the earth’s crust, and low cost of aluminum metal. However, aluminum ion intercalation into crystalline electrode materials is challenging, as the high coulombic charge of trivalent aluminum ions significantly increases the activation energy of diffusion compared to monovalent ions. Chevrel phase Mo6S8 is one of the most well-studied and successful cathode materials for magnesium-ion batteries, partly due to the facile transport of divalent magnesium ions within its crystal structure. Reversible intercalation of aluminum ions within chevrel phase has been reported, though the intercalation mechanism is not well understood at a molecular level.
Here, we report enhanced understanding of aluminum-ion intercalation in chevrel using a combination of spectroscopic, diffraction, and imaging techniques.
Ex situ solid-state 27Al MAS NMR measurements were performed as a function of state-of-charge to observe changes in the environments and populations of aluminum ions within the host crystal structure, revealing both intercalated ions and additional aluminum species associated with surface layers and/or decomposition products. In situ diffraction methods were performed to observe changes in the crystal structure during the cycling process, while transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were conducted to characterize surface structures and compositions. Variable-temperature electrochemical measurements including cyclic voltammetry (CV), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS) were performed to study the effects of temperature on the diffusion of Al3+ ions, electrochemical performance, and capacity retention. In combination, the results yield molecular-level insights into the aluminum-ion intercalation mechanism in the chevrel phase as well as changes of surface compositions and structures upon cycling in the ionic liquid electrolyte.

Figure 1
(Invited) Microscopic Study of Dopant Distribution in Phosphors: Impact on Thermal Quenching and Phosphor Performance
Authors: Martin Lisa I D J , Poelman Dirk , Smet Philippe F , Joos Jonas J 
Published: February 2020

Inorganic luminescent materials or phosphors are currently applied on a large scale in white light-emitting diodes (LEDs) for lighting and display applications. These technologies rely on high-performance phosphors and require subtle fine-tuning of the material composition and the device manufacturing to achieve white LED devices with the desired characteristics1.
Synthesis conditions strongly affect phosphor properties, often in an unpredictable and hard-to-control way. This can be attributed to an incomplete understanding of the effects of local variations in composition, morphology and emission properties on the overall performance of the phosphor.
Since luminescent characterization methods are generally performed on a macroscopic scale, local variations are averaged out, and the detailed information on the interplay between structure and luminescence is lost.
To gain more insight in how performance-determining mechanisms are influenced by synthesis conditions and sample composition, we combine cathodoluminescence (CL) spectroscopy in a scanning electron microscope (SEM) with an energy-dispersive X-ray (EDX) analysis. In SEM-CL-EDX, simultaneous identification of the morphology, the chemical composition and the spectral distribution of a phosphor with a spatial resolution down to 1 µm or less is achieved. For this work a heating stage was added to the setup, allowing to determine thermal quenching profiles on sub-micrometer sized areas.
Temperature-dependent SEM-CL-EDX mappings were performed on SrGa2S4:Eu2+, a material which is known as a saturated green phosphor, especially suitable for display applications2
. This case study revealed that samples with ill-distributed dopant ions show a broad range of local quenching temperatures, as can be seen in Fig. 1. For the associated activation energy an upper limit of 0.61 eV was identified, corresponding to the intrinsic thermal quenching of isolated europium ions. Furthermore, the results confirm a previously suggested thermal quenching model which involves the presence of both isolated and clustered dopant ions3.

References

Smet, P.F.; Parmentier, A.B.; Poelman, D. J. Electrochem.
Soc., 2011. 158(6): p. R37-R54.

Joos, J.J.; Meert, K.W.; Parmentier, A.B.; Poelman, D.; Smet, P.F. Opt.
Mater., 2012. 34(11): p. 1902-1907.

Martin, L.I.D.J.; Poelman, D.; Smet, P.F.; Joos, J.J. ECS J. Solid State Sci. Technol., 2018.
7
(1) p. R3052-R3056.

Figure 1: Distribution of local Eu concentration related to the distribution of local T
0.5 within a single phosphor grain for Sr1-x
Ga2S4:Eu
x
with x = 0.01, 0.03 and 0.07.

Figure 1
Structure Sensitivity of Electrochemical Reactions from First Principles: Applications to Nitrogen and Water Cycles
Authors: Chun Hee-Joon , Deshpande Siddharth , Apaja Vesa , Honkala Karoliina , Zeng Zhenhua , Greeley Jeffrey 
Published: February 2020

Nitrogen cycle electrochemistry is an emerging area of interest in the electrocatalysis community, with applications ranging from removal of nitrates from wastewater streams to the development of fundamental understanding of NO electrochemistry. In spite of a significant amount of fundamental research for this chemistry on single crystal surfaces, however, the mechanistic details of the reactions are not fully known, and even such basic information as the nature of the rate-limiting step is not understood.
In this work, we apply some of the innovations in theoretical electrochemistry that have emerged over the past 5-10 years to the study of NO and nitrate reduction on transition metal surfaces. We begin with a simple Density Functional Theory analysis of direct NO reduction in acid on Pt(111), Pt(100), and Pt(211) surfaces, and we identify potential- and rate-determining steps on each surface, using extensive ab-initio molecular dynamics simulations to estimate the impact of the aqueous environment on surface thermodynamics and kinetics (Ang. Chem. Int. Ed. 2015). We next introduce a novel approach that couples DFT calculations with rigorous kinetic Monte Carlo (kMC) simulations to understand, in unprecedented detail, the effect of higher adsorbed NO coverages on these chemistries, and we demonstrate that these coverage-dependent effects are essential for describing experimentally measured polarization curves (ACS Catalysis 2017).
We subsequently generalize our analysis by developing universal Brønsted-Evans-Polanyi relationships that rigorously relate barriers for proton-coupled electron transfer to surface species to the corresponding thermodynamics across a large space of different transition metals and potentials. These relationships, combined with the potential- and coverage-dependent energetics determined on platinum, provide a basis to extrapolate our mechanistic analyses to other transition metals, including PtSn and related alloys. We employ these techniques to propose design strategies to tune selectivity of NO electroreduction to desired products, including N2 and hydroxylamine, on these different transition metals and alloys.
If time permits, we will briefly describe some additional work on the development of structural and catalytic reactivity models at the interface between thin hydroxyoxide films and precious metal platinum substrates. We will examine the kinetics of the hydrogen evolution reaction as a function of the structure and oxidation state of these interfaces and will demonstrate that the bifunctional nature of the interfaces plays a key role in their electrocatalytic properties.
Electron Transfer Reactions in Three-Nuclear Ti Complexes with π-Acceptor Ligands
Authors: Markovic Aleksandra , Sander Pia , Dosche Carsten , Beckhaus Rüdiger , Wittstock Gunther 
Published: February 2020

Multinuclear transition metal complexes bridged by ligands with extended π-electronic systems such as hexaphenyl-5,6,11,12,17,18-hexaaza-tribiscyclopentadienyl titaniumnaphtylene [(Cp2Ti)3HATN(Ph)6] show a variety of complicated electronic transitions and electron transfer reactions [1]. Therefore, they are intensively investigated as artificial analogues to a number of natural systems capable of converting light into chemical energy by translocating charges over large distances or to generate light efficiently [1]. While a systematic understanding of the photochemistry and electrochemistry has been atained for binuclear complexes [1], much less is known about trinuclear and multinuclear complexes [2].
Trinuclear titanocene(II) complexes include formally three titanocene(II) fragments with two d-electrons, i.e. they contain six potential d-electrons. In this study the complex has been characterised by electrochemical measurements and absorption spectroscopy. The voltammogramm of [(Cp2Ti)3HATN(Ph)6] shows three reduction waves and six oxidation waves.
Solution spectra of [(Cp2Ti)3HATN(Ph)6] and of the electrochemically formed oxidation products show electronic transition in the UV, visible and the NIR ranges. The existence of a single occupied molecular orbital (SOMO) populated by an electron transferred from one of the Ti(II) centers to the HATN(Ph)6 ligand gives rise to several characteristic electronic transitions from which the most prominent is the intervalence charge transfer (IVCT) transition between the Ti(III) center and the remaining Ti(II) centers. Another transition related to the SOMO is the ligand-centered transition from the SOMO to the lowest unoccupied molecular orbital (LUMO). When oxidized to [(Cp2Ti)3HATN(Ph)6]+, the SOMO orbital becomes the LUMO’. If the complex is oxidized to [(Cp2Ti)3HATN(Ph)6]2+, one electron is extracted from the Ti(II). For the reduced form [(Cp2Ti)3HATN(Ph)6]-, the Ti(III) accepted an electron an no IVCT can be observed. In further reduction the “SOMO” is fully occupied and becomes the new HOMO'. In the last reduction an electron is accepted to the one orbital of the Ti(II) and attaining a mixed valence states again.
Finally, the orbital diagram in the accurate energy scale was constructed from the assignment of the transitions, the spectra and the formal potentials obtained from the voltammetric data. From this diagram it becomes evident that removal of an electron from the orbitals of the ligand does not change the energetic position of the Ti orbitals, whereas removal of an electron from one of the Ti centers affects the energy of all orbitals in the complex.
Figure 1: Structure of [(Cp2Ti)3HATN(Ph)6].
References:
[1] S. Kitagawa, S. Masaoka, Coord. Chem. Rev., 246 (2003) 73-88.
[2] I. M. Piglosiewicz, R. Beckhaus, W. Saak and D. Haase, J. Am.
Chem. Soc., 127 (2005) 14190-14191

Figure 1
Application of Electrochemical Impedance Spectroscopy for Evaluating Nanoparticle Agglomeration
Authors: Peters Dennis G , Pence Michael Andrew , Hosseini Seyyedamirhossein 
Published: February 2020

Metallic nanoparticles form dendrite assemblies when they are used as modifying agent in electrochemical reactions.1 These dendrites and the process of their formation can be visualized by application of imaging techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM). Although these approaches provide local information about specific imaging points, electrochemical techniques offer a powerful means to probe the entire electrode surface. For instance, particle coagulation and dendrite formation drastically influence double-layer capacitance and charge-transfer resistance of modified electrodes. Consequently, variation of these parameters during electrochemical reactions can be probed by application of electrochemical impedance spectroscopy (EIS).2

In this work, a modified electrode was fabricated through electrophoretic deposition of copper sulfide nanoplates onto a detachable glassy carbon surface. Then a potential of –1.5 V vs. SCE was applied to a modified electrode for 2 h. Finally, the morphological evolution of the electrode was investigated by application of EIS and SEM methods. Moreover, a random-walk simulation was used to model the agglomeration process. The simulation results were compared to the morphology and EIS spectra of the modified electrode to correlate the simulation with physical information.
References

Manthiram, K.; Surendranath, Y.; Alivisatos, A. P., Dendritic Assembly of Gold Nanoparticles during Fuel-Forming Electrocatalysis. J. Am. Chem. Soc.
2014,
136, 7237–7240.

Gao, S.; Sun, Z.; Liu, W.; Jiao, X.; Zu, X.; Hu, Q.; Sun, Y.; Yao, T.; Zhang, W.; Wei, S., Atomic layer confined vacancies for atomic-level insights into carbon dioxide electroreduction. Nat. Commun.
2017,
8, 14503–14509.
Enhancing the Activity and Stability of Manganese Oxide-Based Catalysts for the Electrochemical Oxygen Evolution Reaction
Authors: Morales Dulce M. , Masa Justus , Antoni Hendrik , Muhler Martin , Schuhmann Wolfgang 
Published: February 2020

Finding efficient non-expensive materials for the electrocatalytic oxygen evolution reaction in alkaline media is one of the major challenges in the development of green energy conversion technologies. Transition metal oxides represent an attractive alternative to the state of the art noble metal-based catalysts due to their high abundance, low cost, and wide versatility regarding structure, composition, oxidation state, morphology and surface area. However, a major drawback of most transition metal oxides is their poor electric conductivity, which hinders their electrocatalytic properties.
In this context, we present manganese oxide-based materials as alternative oxygen evolution electrocatalysts and we discuss different synthesis routes which aim, firstly, to overcome their conductivity limitations, and, secondly, to improve their overall performances regarding activity and stability, by embedding metal oxide particles in a conductive carbon matrix, such as few-layer graphene[1] or carbon nanotubes[2], followed by a thermal treatment step[3]. Since it has been reported that the presence of metal impurities in the carbon supports can substantially promote the electrocatalytic activity of carbon containing catalysts[4,5], we include as a design strategy the incorporation of small amounts of metal particles, such as iron, cobalt and nickel, into the manganese oxide-based composites, and we further discuss their impact on the overall electrocatalytic performance. Finally, we demonstrate the importance of coupling electrochemical methods with spectroscopic techniques for an in-depth characterization of the electrocatalytic materials under reaction conditions.

References:

[1] D.M. Morales, J. Masa, C. Andronescu, Y.U. Kayran, Z. Sun, W. Schuhmann, Electrochim. Acta
222 (2016) 1191–1199.
[2] K. Elumeeva, M. Kazakova, D.M. Morales, D. Medina, A. Selyutin, G. Golubtsov, Y. Ivanov, V. Kuznetzov, A. Chuvilin, H. Antoni, M. Muhler, W. Schuhmann J. Masa, ChemSusChem (2018) DOI: 10.1002/cssc.201702381.
[3] J. Masa, W. Xia, I. Sinev, A. Zhao, Z. Sun, S. Grützke, P. Weide, M. Muhler, W. Schuhmann, Angew.
Chem. Int.
Ed.
53 (2014) 8508–8512.
[4] M. Pumera, H. Iwai, J. Phys. Chem. C
113 (2009) 4401–4405.
[5] C.H.A. Wong, Z. Sofer, M. Kubesova, J. Kucera, S. Matejkova, M. Pumera, Proc. Natl. Acad. Sci. U.S.A.
111 (2014) 13774–13779.

Acknowledgment: The authors are grateful to the BMBF in the framework of the project “Mangan” (FKZ 03EK3548). D. M. Morales acknowledges the financial support from Deutscher Akademischer Austauschdienst (DAAD) and from Consejo Nacional de Ciencia y Tecnología (CONACyT).