bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real Time Observation of Electrochemical Deposition Process of Zinc Dendrites Via Correlative Optical and X-Ray Microscopy
Authors: Park Jeung Hun , Raj Abhishek , Gupta Tanya , Steingart Daniel A 
Published: February 2020

Low cost, durable, and relatively safe electrode materials are highly desirable for electrochemical energy storage devices, but the implementation of many materials, including zinc, is limited by morphological transformations that take place during electrochemical cycling [1]. The formation of unstable growth morphologies, notably dendrites with highly anisotropic and porous structures is vulnerable to mechanical vibrations and can cause catastrophic failure by shorting the anode and the cathode [2]. The development of improved secondary batteries depends critically on a detailed understanding of the physical and electrochemical processes at the electrode-electrolyte solid-liquid interface [3]. Recent advances in in situ electrochemical microscopy [4], with its unique ability to provide simultaneous temporally and spatially resolved information as well as electrochemical parameters, enable exploration of the underlying physics of electrochemical reactions at the solid-liquid interface [5].
In this work, we investigate electrodeposition process that forms and takes place on the surface and inside of metal electrodes at real time. By employing a microfluidic cell and the capability for liquid flow, we can introduce electrolytes (i.e. 8.9M KOH + 0.61M ZnO or 0.5M H2SO4 + 0.1M ZnSO4) with varying composition of metal ions, pH and chemical additives (i.e. Bi2O3 or PbSO4), and apply different current and voltage parameters to investigate their effects on the deposited morphology. We employ in situ correlative light and transmission X-ray microscopies to track nucleation, growth, and propagation of Zn dendrites. We also discuss the effects of additives to the electrolyte, which can change the onset of dendrite formation during the electrodeposition of Zn. We also compare these microfluidic cell results to liquid cell electron microscopy experiments in which we have recorded Zn morphology after galvanostatic deposition, and we will discuss the benefits and pitfalls of the correlative microscopy technique for the study of processes during battery operation.

References:

[1] Y. Li & H. Dai. Chem. Soc. Rev. 43, 5257–5275 (2014).
[2] Z.-L. Wang, D. Xu, J.-J. Xu, & X.-B. Zhang. Chem. Soc. Rev. 43, 7746–7786 (2014).
[3] J. W. Gallaway, D. Desai, A. Gaikwad, C. Corredor, S. Banerjee, & D. Steingart. J. Eectrochem. Soc. 157, A1279–A1286 (2010).
[4] C. P. Grey & J. M. Tarascon. Nat. Mater. 16, 45–56 (2017).
[5] N. Hodnik, G. Dehm, & K. J. J. Mayrhofer. Acc. Chem. Res.
49, 2015–2022 (2016).
[6] We gratefully acknowledge funding supports from the BP Carbon Mitigation Initiative.
X-Ray Tomography and Thermography Investigation of a High-Modulus Solid Electrolyte for All Solid-State Batteries
Authors: Seitzman Natalie , Johnston Steve , Platt Heather A.S. , Harvey Steve , Son Seoung-Bum , Zenyuk Iryna V. , Al-Jassim Mowafak , Pylypenko Svitlana 
Published: February 2020

All solid-state lithium batteries offer a necessary improvement to the safety of electric vehicles (EVs) in addition to the capacity improvements enabled by the use of lithium metal as an anode material. In order to accelerate the use of lithium metal anodes and solid electrolytes in consumer products, it is vital to understand the cycling behavior, electrode-electrolyte interfaces, and failure mechanisms of such systems. A promising class of solid electrolytes for achieving the use of all solid-state batteries in EVs is lithium-phosphorous-sulfides, which includes β-Li3PS4. This electrolyte has an ionic conductivity on the order of 10-3 S cm-1 and can be compressed to 80% density at room temperature.
This work probes the morphological evolution of the electrode-electrolyte interface and observes the growth of lithium dendrites in β-Li3PS4 using x-ray tomography, guided by thermography. Thermography enables the direct visualization of short circuits in the electrolyte, which are shown in Figure 1 to preferentially form in continuous boundary or void spaces, and identifies locations of interest to examine with x-ray tomography. With the density dependence of x-ray microscopy, it is possible to examine the correlation of lithium dendrite growth to voids or phase defects and to better understand the behavior of dendrites in high-modulus electrolyte systems. In order to better understand the reactions and mechanisms occurring during cycling as a function of current density, morphological changes detected with x-ray tomography are correlated with chemical information acquired using energy dispersive spectroscopy (EDS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Results will be presented for cold-pressed pellets of the conductive ceramic powder enclosed in lithium-lithium symmetric cells compared over three conditions: uncycled cells, cells cycled under low current, and cells cycled under high current, both for a specific amount of charge.

Figure 1
(Invited) Understanding Electrocatalytic Pathways in Complex Organic and Inorganic Composites in Aqueous and Non-Aqueous Environments
Authors: Mukerjee Sanjeev 
Published: February 2020

There are very few techniques that lend themselves to rigorous requirements, where the individual role of different transition metal components of nano-phasic materials can be investigated in both amorphous and crystalline forms. We have developed a new analytical technique along with theoretical calculations, which enables the amount and specific adsorption site of species such as H, OH, O, CO, other C1 moieties and even anions such as bisulfate to be determined in situ on a transition metal surfaces using synchrotron XANES data. This technique, commonly called the ‘Delta Mu (∆μ) Technique’ can be taken in situ in both electrochemical cells and operating fuel cells, and can be obtained from a wide variety of transition metal surfaces and alloys, including non-Pt based metal electrocatalysts with element specificity. EXAFS data taken concurrently provide information on the changes in short range atomic order around the absorber atom thereby providing structural information such as bond distances and coordination numbers (thereby information on average cluster size, homogeneity and surface segregation etc.).
In this presentation among other things we will show in-situ XAS study of group of (Metal-Nitrogen-Carbon) MNC catalysts from perspective of metal center. We will demonstrate the presence of ORR active bio-mimetic porphyrin-like FeNx functionalities (Fig.1), as well as other forms of the metal which indicate no catalytic activity. The XAS in-situ studies will be combined with electroanalytical evaluations using cyclic voltammetry (CV) and square wave voltammetry (SWV) as well as in situ Raman spectroscopy. Further the factors governing the ORR activity at MNC centers, such as the Lewis basicity of the carbon support and the accompanying changes in the redox potential of the metal center will be discussed. This presentation will bring together electrochemistry and XAS spectroscopy (including ∆μ) on effect of pH (inner and outer sphere charge transfer) and aqueous vs. non-aqueous electrolyte (concerted vs. non concerted charge transfer).
Elucidating the Pre-Oxygen Evolution Surface Chemistry on Ruthenium Dioxide Surfaces
Authors: Rao Reshma R , Kolb Manuel J , Halck Niels , Pedersen Anders Filsøe , Mehta Apurva , You Hoydoo , Stoerzinger Kelsey A. , Hansen Heine A. , Feng Zhenxing , Zhou Hua , Rossmeisl Jan , Vegge Tejs , Chorkendorff Ib , Stephens Ifan Erfyl Lester , Shao-Horn Yang 
Published: February 2020

The unique interaction between water and rutile Ruthenium Dioxide (RuO2) affords high pseudocapacitance and catalytic activities for a number of reactions such as the oxygen evolution reaction (OER)1,2,3. While the low energy, RuO2 (110) and (100) surfaces have been studied as model systems for gas phase catalysis and ultra high vacuum surface science studies4,5, the nature of adsorbed species in aqueous solutions remains to be understood. In this work, we examine the structural and chemical changes occurring on oriented RuO2 single crystal surfaces as a function of potential, in acidic electrolyte, using in situ synchrotron-based surface X-ray diffraction (crystal truncation rod) measurements. We find that the positions of the surface Ru and O atoms are largely unchanged from 0.5 V to 1.5 V versus the reversible hydrogen electrode (RHE) scale while adsorbed water molecules on the co-ordinatively unsaturated site (CUS) are deprotonated gradually with increasing potential. At oxygen evolution potentials, we observe the formation of an –OO like group on the co-ordinatively unsaturated site, which is the probable precursor of the evolved oxygen. In order to validate experimentally observed changes in the nature of adsorbed oxygen, we use density functional theory to compute surface Pourbaix diagrams that show the most stable surface termination at any given potential. The experimental and computational results are in strong agreement and provide an atomistic understanding of the surface structural changes associated with the redox transitions prior to oxygen evolution and its implications on the oxygen evolution pathway on RuO2.

References

[1] Trasatti S. Electrochimica Acta. 1984;29(11):1503-1512.
[2] Lee Y, Suntivich J, May KJ, Perry EE, Shao-Horn Y. The Journal of Physical Chemistry Letters. 2012;3(3):399-404.
[3] Stoerzinger KA, Qiao L, Biegalski MD, Shao-Horn Y. The Journal of Physical Chemistry Letters. 2014;5:1636-1641.
[4] Over H. Chemical Reviews. 2012;112(6):3356-3426.
[5] Sun Q, Reuter K, Scheffler M. Physical Review B. 2003;67(20):205424.
(Invited) On the Balance of Intercalation and Conversion Reactions in Battery Cathodes
Authors: Hannah Daniel C. , Gautam Gopalakrishnan Sai , Canepa Pieremanuele , Ceder Gerbrand 
Published: February 2020

Batteries based on the intercalation of multivalent ions, such as magnesium, offer substantial improvements in volumetric energy density owing to non-dendritic plating/stripping on high-energy density metal anodes. However, the stability of magnesium oxide (MgO) creates a strong driving force for reactions between Mg2+ ions and transition metal oxide cathodes to follow a conversion pathway (resulting in MgO and reduced transition metal oxides) rather than the desired intercalated pathway. The formation of MgO is particularly problematic: In addition to destroying intercalation cathode material, Mg2+ conductivity in MgO is low enough that MgO is effectively passivating with regard to further insertion/removal of Mg. Such conversion reactions have been observed in several materials and postulated to occur in many others. However, it is not presently known a priori which materials will follow an intercalation (or conversion) reaction pathway: Some materials predicted to be unstable upon magnesiation nevertheless exhibit reversible intercalation, while other seemingly-stable materials undergo conversion reactions.
Understanding which materials favor intercalation (and why) will guide future cathode discovery efforts and can provide insight about which chemical properties govern the balance between conversion and intercalation, aiding the rational design of new materials. In this presentation, I will discuss our efforts to analyze this balance across chemical and structural space (including extension to sulfides, selenides, and other multivalent working ions) using density functional theory (DFT) calculations. I will also describe the trends and insights that emerge from the resulting data, including the impact of polymorph selection and transition metal chemistry on the driving forces for intercalation/conversion.

Figure 1
(Keynote) In-Situ Synthesis of Compact Li2s@Graphene Nanocapsules for High Performance Li-S Batteries
Authors: Tan Guoqiang , Xu Rui , Xing Zhenyu , Yuan Yifei , Wen Jianguo , Liu Cong , Ma Lu , Wu Tianpin , Lu Jun , Ji Xiulei , Amine Khalil 
Published: February 2020

For the practical applications of Li-S batteries, excellent energy/power densities and long cycling lifetimes along with high electrode mass loading must be achieved. This requires rational design of cathode’s architectures to facilitate fast electronic and ionic transport as well as accommodate the electrode’s volumetric change. Here we report a compact Li2S/graphene cathode architectural design, where crystalline Li2S nanoparticles wrapped by graphenes are generated simultaneously by burning lithium foil in CS2 vapor, thus forming Li2S@graphene nanocapsules. This structure represents the high possible volumetric efficiency for accommodating sulfur active species while providing superior electrical properties. As a result, the composite electrode exhibits remarkable electrochemical properties, where at a mass loading of 10 mg cm−2, the electrode delivers high reversible capacity of 1160 mAh g−1
S at 0.1 C rate and 800 mAh g−1
S at 1.0 C rate as well as stable cycle performance.
Figs. 1a,b illustrate the nanocapsule structure of Li2S@graphene. TEM images show that the particles have a compact core-shell shape, where the crystalline Li2S cores display highly ordered lattice fringes, and they are surrounded by a contour coating of ~ 10 to 20 graphene layers, thus forming a capsule-like nanostructure. Figs. 1c-f show the electrochemical performance of Li2S@graphene composite. Even at a high electrode loading of 10 mgLi2S cm−2, the cell delivers a high initial charge capacity of 1600 mAh g−1 and a high discharge capacity of 1160 mAh g−1. The capacity remains at 600 mAh g−1 after 200 cycles. In addition, the cell exhibits a good rate capability with high discharge capacities of 1230 (0.1 C), 1105 (0.2 C), 984 (0.5 C), 802 (1.0 C), and 600 mAh g−1 (2.0 C). This finding is mainly attributed to the improved electrical properties, electrochemical kinetics, and structural stability of Li2S@graphene nanocapsules. In a word, this compact Li2S@graphene capsule nanostructure exhibit good electrochemical performance.
Fig. 1 Structural and electrochemical characterization of Li2S@graphene nanocomposite. (a) TEM images of Li2S@graphene nanocapsules. (b) Schematic showing the compact nanocapsule structure. (c) Voltage profiles and (d) Cycling performance of Li2S@graphene electrode based on electrode loading of 10 mgLi2S cm−2. (e) Voltage profiles at different charge/discharge current densities, and (f) Long rate cycling performance of Li2S@graphene electrode based on electrode loading of 5 mgLi2S cm−2.

Figure 1
(Invited) Lithium Metal Batteries Using 3D Ionic or Electronic Frameworks
Authors: Hu Liangbing 
Published: February 2020

I will discuss our recent progress on Li metal batteries using multilayer Garnet structures, including bilayer and trilayer frameworks. Results based on various cathode including S, oxygen and high voltage cathodes will be discussed.
I will also discuss our results on garnet nanostructures including 3D printed garnet framework, garnet paper and garnet fabrics which function as ionic conductive frameworks to enable stable, high current cycling of thick Li metal anode. Flexible garnet nanofiber-polymer hybrid electrodes with a high tortuosity and excellent mechanical strength will also be discussed.
In the end, I will discuss low-tortuosity Li metal anode guided by anisotropic wood-based carbon framework.
References:

Bilayer Garnet Solid Electrolyte Based High Energy Density Lithium Metal-Sulfur Batteries, Energy and environmental Science, Accepted.

High-Capacity, Low-Tortuosity, and Channel-Guided Lithium Metal Anode. PNAS, 2017.

Flexible, Solid-State Lithium Ion-conducting Membrane with 3D Garnet Nanofiber Networks, PNAS, 2016, 113, 26,7094.
Multifunctional Pyridinium Systems for Nonaqueous Redox Flow Batteries
Authors: Guarr Thomas F. , Petty Anthony , Olson Kevin , Mann Shane 
Published: February 2020

Viologens are among the most thoroughly studied redox active organic compounds, and many examples display two distinct reversible reductions under appropriate conditions. However, by introducing p-phenylene or p-biphenylene bridges between the pyridinium rings, substantially different electrochemical behavior is observed. Specifically, the stabilization afforded by the quinoidal form of the doubly reduced species can lead to coalescence of the pyridinium reduction peaks into a single, net 2e- wave. We have employed simple and straightforward synthetic routes to various flavors of multi-pyridinium materials. Two, three, and four electron systems have been demonstrated, and more complex systems capable of accepting six or more electrons are currently being developed. These materials are well characterized by NMR, ESI-MS, electrochemical, and spectroelectrochemical methods. Correlations between structure, redox potential, spectroscopic properties, and stability will be described, as will our efforts to develop and optimize such systems for applications in redox flow batteries.
Nested ZnO Nanostructure Gas Sensor with AZO Coating By Atomic Layer Deposition
Authors: Lin Pengtao , Chen Xin , Zhang Kai , Baumgart Helmut 
Published: February 2020

ZnO is a well-known Metal Oxide Semiconductor (MOS) material used in gas sensor applications due to its good electrical property, wide band gape of 3.37 eV, ~60 meV exciton binding energy, low cost, and high mechanical stability. Especially, ZnO nanorod structure is widely investigated in gas detection due to its high surface-to-volume ratio, nontoxicity, and suitable doping. Numerous methods have been applied to enhance the sensing performance of ZnO nanostructure gas sensors. In this research, a coaxial nanorod/nanotube structure was fabricated to improve the sensing response of ZnO nanorods to ethanol vapor, as shown in Figure 1. Also, due to additional oxygen vacancies, Al doped ZnO (AZO) thin films were deposited on the surface of ZnO nanorod/nanotube to further enhance the sensitivity of ZnO nanorods.
In this study, the ZnO seed layers were deposited on Si wafer by Atomic Layer Deposition (ALD) with diethylzinc ((C2H5)2Zn) and DI water as precursors of zinc and oxygen. Physical vapor deposition (PVD) was carried out to synthesize aligned ZnO nanorods shown in Figure 1(a). There was a layer of Al2O3 as sacrificial spacer deposited on the surface of ZnO nanorods by ALD with TMA (Al2(CH3)6) and DI water as precursors shown in Figure 1(b). An additional layer of ZnO thin film was synthesized by ALD shown in Figure 1(c) and Figure 2(a). To expose the Al2O3 sacrificial spacer layer, Precision Ion Polishing System (PIPS) was introduced to remove the top cover of synthesized ZnO nanorods shown in Figure 1(d) and Figure 2(b). Then Sodium hydroxide (NaOH) was applied to remove the Al2O3 layer to form ZnO nanorod/nanotube structure as shown in Figure 1(e) and Figure 2(c). As shown in Figure 1(f) and Figure 2(d), AZO thin films were deposited on the surface of ZnO nanorod/nanotube by ALD to further enhance its sensing performance to ethanol vapor. Field emission scanning electron microscopy (FE-SEM) to investigate the morphology of ZnO nanorod/nanotube before and after coated with AZO thin films by ALD. The crystal structures of ZnO nanorod/nanotube before and after coated with AZO thin films were analyzed by X-ray diffraction (XRD).
To investigate the sensing performance of ZnO nanorod/nanotube to ethanol vapor, a gas sensor testing system was designed and built with a sealed reaction chamber, ethanol vapor generator, testing circuit, and controlled heating system. The physical change of ZnO nanorods to ethanol vapor is resistance. Therefore, the resistance of ZnO nanorod/nanotube was recorded by the home-built sensor testing system based on Labview and CompactRio system from National Instruments. ZnO nanorod/nanotube samples before and after coated with AZO thin films were tested under various volumes of ethanol vapor at different temperatures to analyze their sensing responses. A sensing response comparison was made between ZnO nanorods and ZnO nanorod/nanotube.

Figure 1
New Class of Non-Corrosive, Non-Nucleophilic and Highly Efficient Electrolytes for Rechargeable Magnesium Batteries
Authors: Fichtner Maximilian , Zhao-Karger Zhirong 
Published: February 2020

It will be shown that fluorinated alkoxyborates based magnesium electrolytes are weakly coordinated systems, which exhibit a high anodic stability (4.3 V vs. Mg), high ionic conductivity (7 mS/cm) and high Coulombic efficiency (>99%) of reversible magnesium deposition. Owing to the non-corrosive, chemically stable nature and the robust, economic synthesis in one step from commercially available materials, this design concept of new, weakly coordinated ion conducting salts opens a promising avenue towards the realization of high-energy magnesium batteries.
Synthesis, chemical and structural analysis and electrochemical properties will be presented, as well as its application to Mg-S batteries, where it shows superior performance.
Speciation and Electrochemical Properties of Electrolytes for Mg-Ion Batteries
Authors: Merrill Laura C. , Schaefer Jennifer L. 
Published: February 2020

Rechargeable magnesium-ion batteries are under investigation as a possible alternative platform to lithium-ion. Magnesium metal serves as a viable anode for post lithium-ion batteries due to its high volumetric charge capacity and widespread abundance. The electrolyte is identified as a limiting factor in magnesium batteries, as many analogous electrolytes to lithium-ion batteries can passivate the magnesium metal surface preventing rechargeability. Both electrolyte salt(s) and solvent(s) must be chosen to ensure chemical compatibility while facilitating desired electrochemical activity. Here we report our recent efforts to understand the effects of speciation and electrochemical performance of magnesium bis(disilizane)-based liquid electrolytes. We find that the solvent and anion types both effect electrolyte equilibration and complexation, resulting in varying conditioning procedures required, the reversibility and facileness of magnesium deposition and stripping, and oxidative stability.
Lithium Doped High-Performance Intercalation Cathode Materials for Sodium Ion Batteries
Authors: Yang Lufeng , Li Xiang , Ma Xuetian , Xiong Shan , Hu Yan-Yan , Liu Meilin , Chen Hailong 
Published: February 2020

High capacity, low cost and long cycle life cathode materials are very much desired to develop high performance sodium-ion batteries (SIBs), which are considered as a possible solution for grid level electrochemical energy storage. Sodium manganese oxides with different compositions and crystal structures are a class of intercalation cathode materials that have high promise because of their high initial capacity and low cost, owing to the use of earth abundant metal, Mn. However, many sodium manganese oxides compounds suffer from fast capacity decay primarily attributed to the irreversible phase transitions in the electrochemical cycling processes. In this work, we report our investigation on a group of Mn-based cathodes with using an effective strategy of mitigating and delaying the phase transitions by compositional design. We report the design, synthesis, electrochemical testing and cycling mechanism study on the compounds with a general formula of Nax(LiyMn1-y)O2 with using lithium as the doping element. Many of this group of materials demonstrated very high initial capacity of >200 mAh/g and good capacity retentions. In-operando X-ray diffraction (XRD), Rietveld refinement and 7Li solid state NMR characterizations are conducted to elucidate the cycling mechanisms of the materials. The stability of the Li-doped structure, the effects of lithium doping and the fate of lithium in extended cycling are also discussed.
Figure 1. The voltage profiles (a) and in operando XRD patterns (b) of the lithium doped sodium manganese oxide cathode.

Figure 1