A5034568090- Advanced Battery Materials and Technologies
- Advanced battery technologies research
- Advancements in Battery Materials
- Perovskite Materials and Applications
- Ionic liquids properties and applications
- Solid-state spectroscopy and crystallography
- Supercapacitor Materials and Fabrication
- Electrocatalysts for Energy Conversion
- Material Dynamics and Properties
- Methane Hydrates and Related Phenomena
- Surfactants and Colloidal Systems
- Ferroelectric and Piezoelectric Materials
- Advanced Battery Technologies Research
- Thermodynamic properties of mixtures
- Chalcogenide Semiconductor Thin Films
- Inorganic Fluorides and Related Compounds
- Climate change and permafrost
- Catalysis and Oxidation Reactions
- biodegradable polymer synthesis and properties
- Quantum Dots Synthesis And Properties
- Photochemistry and Electron Transfer Studies
- Gold and Silver Nanoparticles Synthesis and Applications
- Nanopore and Nanochannel Transport Studies
- Polymer crystallization and properties
- Recycling and Waste Management Techniques
University of Colorado Boulder
2021-2024
Argonne National Laboratory
2021-2023
SLAC National Accelerator Laboratory
2020-2021
Max Planck Institute for Polymer Research
2016-2021
Energy Storage Systems (United States)
2020
Menlo School
2020
University of Applied Sciences Mainz
2020
Johannes Gutenberg University Mainz
2016-2019
Czech Academy of Sciences, Institute of Physics
2017-2019
By using coordinating anions such as acetate, a water-in-salt-like coordination environment of Zn ions is achieved in relatively dilute conditions, leading to prolonged and efficient cycling zinc metal anodes.
Methylammonium lead iodide (MAPbI3) perovskite shows an outstanding performance in photovoltaic devices. However, certain material properties, especially the possible ferroic behavior, remain unclear. We observed distinct nanoscale periodic domains piezoresponse of MAPbI3(Cl) grains. The structure and orientation these striped indicate ferroelasticity as their origin. By correlating vertical lateral force microscopy experiments performed at different sample orientations with X-ray...
Methylammonium lead halide perovskites (MAPbI3) are very sensitive to humid environments. We performed in situ scanning force microscopy and X-ray diffraction measurements on MAPbI3 films track changes the film morphology crystal structure upon repeated exposure a high relative humidity environment (80%). found that appearance of monohydrate (MAPbI3·H2O) Bragg reflections coincided with additional grain boundaries. Prolonging time induced more boundaries steps films, peak intensities...
In the present contribution, we investigated catalytically active mixtures of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and aqueous H2O2 by molecular dynamics simulations. It is clearly observable that HFIP molecule strongly binds to H2O2, which necessary for desired catalytic reaction occur. Upon addition substrate cyclooctene solution, this interaction enhanced, suggests activity increased presence hydrocarbon. We could observe microheterogeneous structure mixture, result separation...
The concept of water-in-salt electrolytes was introduced recently, and these systems have been successfully applied to yield extended operation voltage hence significantly improved energy density in aqueous Li-ion batteries. In the present work, results X-ray scattering Fourier-transform infrared spectra measurements over a wide range temperatures salt concentrations are reported for LiTFSI (lithium bis(trifluoromethane sulfonyl)imide)-based electrolyte. Classical molecular dynamics...
Applications of aqueous zinc batteries for grid-scale energy storage are limited by their poor reversibility and the competing water splitting reaction. The recent invention a water-in-salt (WIS) electrolyte concept provides new route enabling stable highly reversible battery chemistry. In present work, mixed bis(trifluoromethane sulfonyl)imide (Zn(TFSI)2) LiTFSI WIS was studied using X-ray total scattering, absorption, Fourier transform infrared spectroscopy in conjunction with classical...
The solid electrolyte interphase (SEI) is an integral part of Li-ion batteries and their performance, representing the key enabler for reversibility also serving as a major source capacity loss dictating cell kinetics. In pervasive LiPF6-containing electrolytes, LiF one SEI's components; however, its formation mechanism remains unclear. Electrochemically, two separate reduction pathways could lead to LiF, either via direct anion or electrocatalytic transformation HF. This work aims shed...
Aqueous zinc-ion batteries (ZIBs) employing zinc metal anodes are gaining traction as for moderate to long duration energy storage at scale. However, corrosion of the anode through reaction with water limits battery efficiency. Much research in past few years has focused on additives that decrease hydrogen evolution, but precise mechanisms by which this takes place often understudied and remain unclear. In work, we study role an acetonitrile antisolvent additive improving performance aqueous...
The absence of entanglements, the more compact structure and faster diffusion in melts cyclic poly(ethylene oxide) (PEO) chains have consequences on their crystallization behavior at lamellar spherulitic length scales. Rings with molecular weight below entanglement (M < Me), attain equilibrium configuration composed from twice-folded a periodicity that is half corresponding linear chains. M > Me undergo distinct step-like conformational changes to crystalline configuration. melt this crystal...
After a century of research, the potential-dependent ion distribution at electrode/electrolyte interfaces is still under debate. In particular for solvent-free electrolytes such as room-temperature ionic liquids, classical theories electrical double layer are not applicable. Using combination in situ high-energy X-ray reflectivity and impedance spectroscopy measurements, we determined this with sub-molecular resolution. We find oscillatory charge density profiles consisting alternating...
The pursuit of structure-property relationships in crystalline metal halide perovskites (MHPs) has yielded an unprecedented combination advantageous characteristics for wide-ranging optoelectronic applications. While MHP structures are readily accessible through diffraction-based structure refinements, providing a clear view associated long-range ordering, the local more recently discovered glassy states remain unexplored. Herein, we utilize Raman spectroscopy, solid-state nuclear magnetic...
A common feature of ionic liquids composed cations with long aliphatic side chains is structural heterogeneities on the nanometer length scale. This so-called microphase separation arises from clustering moieties. The temperature dependence liquid bulk structure was studied by small-angle X-ray and neutron scattering for a set methylimidazolium ([C18C1im]+, [C22C1im]+) based tris(pentafluoroethyl)trifluorophosphate ([FAP]-), bis(trifluoromethylsulfonyl)imide ([NTf2]-),...
Surface induced smectic order has been observed in the ionic liquid [C<sub>22</sub>C<sub>1</sub>im]<sup>+</sup>[NTf<sub>2</sub>] over an extremely wide temperature range of 88 K.
The molecular-scale structure and dynamics of confined liquids has increasingly gained relevance for applications in nanotechnology. Thus, a detailed knowledge the on molecular length scales is great interest fundamental applied sciences. To study structures under dynamic conditions, we constructed an situ X-ray surface forces apparatus (X-SFA). This novel device can create precisely controlled slit-pore confinement down to dimensions 10 nm scale by using cylinder-on-flat geometry first...
The anisotropic charge carrier diffusion coupled to ferroelastic twin domains in methylammonium lead iodide opens possibilities for further optimization of perovskite solar cells and optoelectronic devices <italic>via</italic> strain engineering heat treatments.
We present a quantitative description of ice premelting in permafrost model systems. Experimental data on the interfacial ice/clay nano composites was obtained by high energy X-ray diffraction.
We report the synthesis and crystallization behavior of polyethylene-like polyphosphates with a precise spacing 20, 30, 40 methylene groups between each phosphate group, which determined crystal structure, lamellar, thickness.
At solid/ice interfaces, a premelting layer is formed at temperatures below the melting point of bulk water. However, structural and dynamic properties within have been topic intense debate. Herein, we determined translational diffusion coefficient Dt water in ice/clay nanocomposites serving as model systems for permafrost by quasi-elastic neutron scattering. Below point, rapid decrease found charged hydrophilic vermiculite, uncharged kaolin, more hydrophobic talc, reaching plateau values -4...
The salt-induced microheterogeneity (MH) formation in binary liquid mixtures is studied by small-angle x-ray scattering (SAXS) and state theory. Previous experiments have shown that this phenomenon occurs for antagonistic salts, whose cations anions prefer different components of the solvent mixture. However, so far precise mechanism leading to characteristic length scale MHs has remained unclear. Here, it can be generated competition short-ranged interactions long-ranged monopole-dipole...
Using nanoscale building blocks to construct hierarchical materials is a radical new branch point in discovery that promises structures and emergent functionality. Understanding the design principles govern nanoparticle assembly critical moving this field forward. By exploiting mixed ligand environments target patchy surfaces, we have demonstrated novel method of colloidal quantum dot (QD) gives rise 2D structures. The equilibration solutions spherical quasispherical QDs, including CdS,...
Atomic layer deposition (ALD) was used to control the stoichiometry of thin lithium aluminosilicate films, thereby enabling crystallization into ion-conducting β-eucryptite LiAlSiO4 phase. The rapid thermal annealed ALD film developed a well-defined epitaxial relationship silicon substrate: β-LiAlSiO4 (12̅10)||Si (100) and (101̅0)||Si (001). extrapolated room temperature ionic conductivity found be 1.2 × 10–7 S/cm in [12̅10] direction. Because unique 1-D channel along c axis β-LiAlSiO4, has...
In this study, the complex coacervation mechanism of Lauric arginate ester (LAE) with λ-carrageenan was studied using turbidimetry, light scattering and electrophoresis. The complexes formed were found to have a bilayer-like structure small angle X-ray (SAXS) cryo-TEM (transmission electron microscopy). It observed that mixing LAE Sodium dodecyl sulfate (SDS) could significantly reduce interactions between mixed micelles λ-carrageenan. LAE/SDS be predominantly entropy driven. Mixed LAE/Tween...
Aqueous electrolytes composed of 0.1 M zinc bis(trifluoromethylsulfonyl)imide (Zn(TFSI)2) and acetonitrile (ACN) were studied using combined experimental simulation techniques. The electrolyte was found to be electrochemically stable when the ACN V% is higher than 74.4. In addition, it that ionic conductivity mixed solvent changes as a function composition, maximum observed at 91.7 although salt concentration same. This behavior qualitatively reproduced by molecular dynamics (MD)...