A Class of Sodium Transition-Metal Sulfide Cathodes With Anion Redox.

Sodium-ion batteries (SIBs) are entering commercial relevance as a sustainable and low-cost alternative to lithium-ion batteries. Improving the energy density of SIBs is critical to enable their widespread adoption. Here, a new class of cathode materials NaMS (M = Co, Mn, Fe, and Zn) that exhibit high charge-storage capacity is reported.

Lithiation Gradients and Tortuosity Factors in Thick NMC111-Argyrodite Solid-State Cathodes.

Achieving high energy density in all-solid-state lithium batteries will require the design of thick cathodes, and these will need to operate reversibly under normal use conditions. We use high-energy depth-profiling X-ray diffraction to measure the localized lithium content of LiNiMnCoO (NMC111) through the thickness of 110 μm thick composite cathodes. The composite cathodes consisted of NMC111 of varying mass loadings mixed with argyrodite solid electrolyte LiPSCl (LPSC).

Methods for Tomographic Segmentation in Pseudo-Cylindrical Coordinates for Bobbin-Type Batteries.

High-resolution X-ray computed tomography (CT) has become an invaluable tool in battery research for its ability to probe phase distributions in sealed samples. The Cartesian coordinates used in describing the CT image stack are not appropriate for understanding radial dependencies, like that seen in bobbin-type batteries. The most prominent of these bobbin-type batteries is alkaline Zn-MnO, which dominates the primary battery market.

Tailoring Electrode-Electrolyte Interfaces in Lithium-Ion Batteries Using Molecularly Engineered Functional Polymers.

Electrode-electrolyte interfaces (EEIs) affect the rate capability, cycling stability, and thermal safety of lithium-ion batteries (LIBs). Designing stable EEIs with fast Li transport is crucial for developing advanced LIBs. Here, we study Li kinetics at EEIs tailored by three nanoscale polymer thin films via chemical vapor deposition (CVD) polymerization.

X-ray spatial profiling reveals uneven compression of electrode assemblies and steep lateral gradients in lithium-ion coin cells.

Coin cells are used extensively as test devices in battery research for evaluation of new materials and optimization of cycling protocols. In this study, in situ X-ray diffraction profilometry is used to characterize spatial distribution of the active materials, lithiation, and phase distribution in electrodes of NCM523/graphite coin cells. The X-ray data indicate uneven areal compression of the electrode assembly in such cells, which we trace to a specific design feature that leads to elastic deformation of a metal spacer.

Polymorphism in a high-entropy alloy.

Polymorphism, which describes the occurrence of different lattice structures in a crystalline material, is a critical phenomenon in materials science and condensed matter physics. Recently, configuration disorder was compositionally engineered into single lattices, leading to the discovery of high-entropy alloys and high-entropy oxides. For these novel entropy-stabilized forms of crystalline matter with extremely high structural stability, is polymorphism still possible? Here by employing in situ high-pressure synchrotron radiation X-ray diffraction, we reveal a polymorphic transition from face-centred-cubic (fcc) structure to hexagonal-close-packing (hcp) structure in the prototype CoCrFeMnNi high-entropy alloy.

Quantifying the Nucleation and Growth Kinetics of Microwave Nanochemistry Enabled by in Situ High-Energy X-ray Scattering.

The fast reaction kinetics presented in the microwave synthesis of colloidal silver nanoparticles was quantitatively studied, for the first time, by integrating a microwave reactor with in situ X-ray diffraction at a high-energy synchrotron beamline. Comprehensive data analysis reveals two different types of reaction kinetics corresponding to the nucleation and growth of the Ag nanoparticles. The formation of seeds (nucleation) follows typical first-order reaction kinetics with activation energy of 20.

Strain response of thermal barrier coatings captured under extreme engine environments through synchrotron X-ray diffraction.

The mechanical behaviour of thermal barrier coatings in operation holds the key to understanding durability of jet engine turbine blades. Here we report the results from experiments that monitor strains in the layers of a coating subjected to thermal gradients and mechanical loads representing extreme engine environments. Hollow cylindrical specimens, with electron beam physical vapour deposited coatings, were tested with internal cooling and external heating under various controlled conditions.

In operando spatiotemporal study of Li(2)O(2) grain growth and its distribution inside operating Li-O(2) batteries.

Nanocrystalline lithium peroxide (Li2 O2 ) is considered to play a critical role in the redox chemistry during the discharge-charge cycling of the Li-O2 batteries. In this report, a spatially resolved, real-time synchrotron X-ray diffraction technique was applied to study the cyclic formation/decomposition of Li2 O2 crystallites in an operating Li-O2 cell. The evaluation of Li2 O2 grain size, concentration, and spatial distribution inside the cathode is demonstrated under the actual cycling conditions.

Quantitative determination of fragmentation kinetics and thermodynamics of colloidal silver nanowires by in situ high-energy synchrotron X-ray diffraction.

Colloidal silver nanowires become instable and tend to fragment into shortened nanorods and nanoparticles at elevated temperatures. Such morphological variations are associated with the transformation of crystalline structures from the body-centered tetragonal (b.c.

Synchrotron X-ray measurement techniques for thermal barrier coated cylindrical samples under thermal gradients.

Measurement techniques to obtain accurate in situ synchrotron strain measurements of thermal barrier coating systems (TBCs) applied to hollow cylindrical specimens are presented in this work. The Electron Beam Physical Vapor Deposition coated specimens with internal cooling were designed to achieve realistic temperature gradients over the TBC coated material such as that occurring in the turbine blades of aeroengines. Effects of the circular cross section on the x-ray diffraction (XRD) measurements in the various layers, including the thermally grown oxide, are investigated using high-energy synchrotron x-rays.

Reversibility of anodic lithium in rechargeable lithium-oxygen batteries.

Non-aqueous lithium-air batteries represent the next-generation energy storage devices with very high theoretical capacity. The benefit of lithium-air batteries is based on the assumption that the anodic lithium is completely reversible during the discharge-charge process. Here we report our investigation on the reversibility of the anodic lithium inside of an operating lithium-air battery using spatially and temporally resolved synchrotron X-ray diffraction and three-dimensional micro-tomography technique.

Microfocused X-ray study on precipitate formation in the separator region of nonaqueous Li-O(2) batteries.

Using a microfocused synchrotron X-ray diffraction (μ-XRD) method, we systematically investigated the distributions of insoluble lithium precipitates, which formed through electrolyte decomposition, separately in all three regions (cathode, separator, and anode) of failed batteries with a spatial resolution of 20 μm. We found unexpectedly that there was a significantly higher concentration (almost twice as much) of precipitates in the separator than in the cathode. SEM revealed that the precipitates grew on the separator fiber surface, ultimately obstructing the pores serving as the ion-transport channel.

Ambient-stable tetragonal phase in silver nanostructures.

Crystallization of noble metal atoms usually leads to the highly symmetric face-centred cubic phase that represents the thermodynamically stable structure. Introducing defective microstructures into a metal crystal lattice may induce distortions to form non-face-centered cubic phases when the lateral dimensions of objects decrease down to nanometre scale. However, stable non-face-centered cubic phases have not been reported in noble metal nanoparticles.

Layering of [BMIM]+-based ionic liquids at a charged sapphire interface.

The structure of two model room temperature ionic liquids, [BMIM](+)[PF(6)](-) and [BMIM](+)[BF(4)](-), near the solid/liquid interface with charged Al(2)O(3)(0001) (sapphire) was determined with subnanometer resolution by high energy (72.5 keV) x-ray reflectivity. [BMIM](+)[PF(6)](-) exhibits alternately charged, exponentially decaying, near-surface layering.

Molecular layering of fluorinated ionic liquids at a charged sapphire (0001) surface.

Room-temperature ionic liquids (RTILs) are promising candidates for a broad range of "green" applications, for which their interaction with solid surfaces plays a crucial role. In this high-energy x-ray reflectivity study, the temperature-dependent structures of three ionic liquids with the tris(pentafluoroethyl)trifluorophosphate anion in contact with a charged sapphire substrate were investigated with submolecular resolution. All three RTILs show strong interfacial layering, starting with a cation layer at the substrate and decaying exponentially into the bulk liquid.

Water and ice in contact with octadecyl-trichlorosilane functionalized surfaces: a high resolution x-ray reflectivity study.

We present a high energy x-ray reflectivity study of the density profiles of water and ice at hydrophobic and hydrophilic substrates. At the hydrophobic water/octadecyl-trichlorosilane (water-OTS) interface, we find clear evidence for a thin density depletion layer with an integrated density deficit corresponding to approximately 40% of a monolayer of water molecules. We discuss the experimental results in terms of a simple model of hydrophobic/hydrophilic solid-liquid interfaces.

High-resolution in situ x-ray study of the hydrophobic gap at the water-octadecyl-trichlorosilane interface.

The knowledge of the microscopic structure of water at interfaces is essential for the understanding of interfacial phenomena in numerous natural and technological environments. To study deeply buried liquid water-solid interfaces, high-energy x-ray reflectivity measurements have been performed. Silicon wafers, functionalized by a self-assembled monolayer of octadecyl-trichlorosilane, provide strongly hydrophobic substrates.

The controlled evolution of a polymer single crystal.

We present a method for controlling the initiation and kinetics of polymer crystal growth using dip-pen nanolithography and an atomic force microscope tip coated with poly-dl-lysine hydrobromide. Triangular prisms of the polymer epitaxially grow on freshly cleaved mica substrates, and their in-plane and out-of-plane growth rates can be controlled by raster scanning the coated tip across the substrate. Atomic force microscope images were concomitantly recorded, providing a set of photographic images of the process as it spans the nanometer- to micrometer-length scales as a function of environmental conditions.