Entropy-Stabilized Multication Fluorides as a Conversion-Type Cathode for Li-Ion Batteries-Impact of Element Selection.

Metal fluorides (e.g., FeF and FeF) have received attention as conversion-type cathode materials for Li-ion batteries due to their higher theoretical capacity compared to that of common intercalation materials.

OsO as the Contrast-Generating Chemical Species of Osmium-Stained Biological Tissues in Electron Microscopy.

Electron imaging of biological samples stained with heavy metals has enabled visualization of subcellular structures critical in chemical-, structural-, and neuro-biology. In particular, osmium tetroxide (OsO) has been widely adopted for selective lipid imaging. Despite the ubiquity of its use, the osmium speciation in lipid membranes and the process for contrast generation in electron microscopy (EM) have continued to be open questions, limiting efforts to improve staining protocols and therefore high-resolution nanoscale imaging of biological samples.

Coherent Erbium Spin Defects in Colloidal Nanocrystal Hosts.

We demonstrate nearly a microsecond of spin coherence in Er ions doped in cerium dioxide nanocrystal hosts, despite a large gyromagnetic ratio and nanometric proximity of the spin defect to the nanocrystal surface. The long spin coherence is enabled by reducing the dopant density below the instantaneous diffusion limit in a nuclear spin-free host material, reaching the limit of a single erbium spin defect per nanocrystal. We observe a large Orbach energy in a highly symmetric cubic site, further protecting the coherence in a qubit that would otherwise rapidly decohere.

Polymorphism in the Ruddlesden-Popper Nickelate LaNiO: Discovery of a Hidden Phase with Distinctive Layer Stacking.

We report the discovery of a novel form of Ruddlesden-Popper (RP) nickelate that stands as the first example of long-range, coherent polymorphism in this class of inorganic solids. Rather than the well-known, uniform stacking of perovskite blocks ubiquitously found in RP phases, this newly discovered polymorph of the bilayer RP phase LaNiO adopts a novel stacking sequence in which single-layer and trilayer blocks of NiO octahedra alternate in a "1313" sequence. Crystals of this new polymorph are described in space group , although we note evidence for a competing variant.

Effect of Antisolvent Additives in Aqueous Zinc Sulfate Electrolytes for Zinc Metal Anodes: The Case of Acetonitrile.

Aqueous zinc-ion batteries (ZIBs) employing zinc metal anodes are gaining traction as batteries for moderate to long duration energy storage at scale. However, corrosion of the zinc metal anode through reaction with water limits battery efficiency. Much research in the past few years has focused on additives that decrease hydrogen evolution, but the precise mechanisms by which this takes place are often understudied and remain unclear.

Electrolyte Reactivity on the MgVO Cathode Surface.

Predictive understanding of the molecular interaction of electrolyte ions and solvent molecules and their chemical reactivity on electrodes has been a major challenge but is essential for addressing instabilities and surface passivation that occur at the electrode-electrolyte interface of multivalent magnesium batteries. In this work, the isolated intrinsic reactivities of prominent chemical species present in magnesium bis(trifluoromethanesulfonimide) (Mg(TFSI)) in diglyme (G2) electrolytes, including ionic (TFSI, [Mg(TFSI)], [Mg(TFSI):G2], and [Mg(TFSI):2G2]) as well as neutral molecules (G2) on a well-defined magnesium vanadate cathode (MgVO) surface, have been studied using a combination of first-principles calculations and multimodal spectroscopy analysis. Our calculations show that nonsolvated [Mg(TFSI)] is the strongest adsorbing species on the MgVO surface compared with all other ions while partially solvated [Mg(TFSI):G2] is the most reactive species.

Hybrid organic-inorganic two-dimensional metal carbide MXenes with amido- and imido-terminated surfaces.

Two-dimensional (2D) transition-metal carbides and nitrides (MXenes) combine the electronic and mechanical properties of 2D inorganic crystals with chemically modifiable surfaces, which provides an ideal platform for both fundamental and applied studies of interfaces. Good progress has been achieved in the functionalization of MXenes with small inorganic ligands, but relatively little work has been reported on the covalent bonding of various organic groups to MXene surfaces. Here we synthesize a family of hybrid MXenes (h-MXenes) that incorporate amido- and imido-bonding between organic and inorganic parts by reacting halogen-terminated MXenes with deprotonated organic amines.

Nanoceria Aggregate Formulation Promotes Buffer Stability, Cell Clustering, and Reduction of Adherent Biofilm in .

is one of the key etiological factors in tooth-borne biofilm development that leads to dental caries in the presence of fermentable sugars. We previously reported on the ability of acid-stabilized nanoceria (CeO-NP) produced by the hydrolysis of ceric salts to limit biofilm adherence of non-bactericidal mechanism(s). Herein, we report a chondroitin sulfate A (CSA) formulation (CeO-NP-CSA) comprising nanoceria aggregates that promotes resistance to bulk precipitation under a range of conditions with retention of the biofilm-inhibiting activity, allowing for a more thorough mechanistic study of its bioactivity.

Enabling selective zinc-ion intercalation by a eutectic electrolyte for practical anodeless zinc batteries.

Two major challenges hinder the advance of aqueous zinc metal batteries for sustainable stationary storage: (1) achieving predominant Zn-ion (de)intercalation at the oxide cathode by suppressing adventitious proton co-intercalation and dissolution, and (2) simultaneously overcoming Zn dendrite growth at the anode that triggers parasitic electrolyte reactions. Here, we reveal the competition between Zn vs proton intercalation chemistry of a typical oxide cathode using ex-situ/operando techniques, and alleviate side reactions by developing a cost-effective and non-flammable hybrid eutectic electrolyte. A fully hydrated Zn solvation structure facilitates fast charge transfer at the solid/electrolyte interface, enabling dendrite-free Zn plating/stripping with a remarkably high average coulombic efficiency of 99.

Direct synthesis and chemical vapor deposition of 2D carbide and nitride MXenes.

Two-dimensional transition-metal carbides and nitrides (MXenes) are a large family of materials actively studied for various applications, especially in the field of energy storage. MXenes are commonly synthesized by etching the layered ternary compounds, called MAX phases. We demonstrate a direct synthetic route for scalable and atom-economic synthesis of MXenes, including compounds that have not been synthesized from MAX phases, by the reactions of metals and metal halides with graphite, methane, or nitrogen.

Variational Convolutional Autoencoders for Anomaly Detection in Scanning Transmission Electron Microscopy.

Identifying point defects and other structural anomalies using scanning transmission electron microscopy (STEM) is important to understand a material's properties caused by the disruption of the regular pattern of crystal lattice. Due to improvements in instrumentation stability and electron optics, atomic-resolution images with a field of view of several hundred nanometers can now be routinely acquired at 1-10 Hz frame rates and such data, which often contain thousands of atomic columns, need to be analyzed. To date, image analysis is performed largely manually, but recent developments in computer vision (CV) and machine learning (ML) now enable automated analysis of atomic structures and associated defects.

Parabolic Potential Surfaces Localize Charge Carriers in Nonblinking Long-Lifetime "Giant" Colloidal Quantum Dots.

Materials for studying biological interactions and for alternative energy applications are continuously under development. Semiconductor quantum dots are a major part of this landscape due to their tunable optoelectronic properties. Size-dependent quantum confinement effects have been utilized to create materials with tunable bandgaps and Auger recombination rates.

β-VO as Magnesium Intercalation Cathode.

Magnesium batteries have attracted great attention as an alternative to Li-ion batteries but still suffer from limited choice of positive electrode materials. VO exhibits high theoretical capacities, but previous studies have been mostly limited to α-VO. Herein, we report on the β-VO polymorph as a Mg intercalation electrode.

Ingrained: An Automated Framework for Fusing Atomic-Scale Image Simulations into Experiments.

To fully leverage the power of image simulation to corroborate and explain patterns and structures in atomic resolution microscopy, an initial correspondence between the simulation and experimental image must be established at the outset of further high accuracy simulations or calculations. Furthermore, if simulation is to be used in context of highly automated processes or high-throughput optimization, the process of finding this correspondence itself must be automated. In this work, "ingrained," an open-source automation framework which solves for this correspondence and fuses atomic resolution image simulations into the experimental images to which they correspond, is introduced.

Investigation of Ca Insertion into α-MoO Nanoparticles for High Capacity Ca-Ion Cathodes.

Calcium-ion batteries (CIBs) are a promising alternative to lithium-ion batteries (LIBs) due to the low redox potential of calcium metal and high abundance of calcium compounds. Due to its layered structure, α-MoO is regarded as a promising cathode host lattice. While studies have reported that α-MoO can reversibly intercalate Ca ions, limited electrochemical activity has been noted, and its reaction mechanism remains unclear.

The Key Role of Tin (Sn) in Microstructure and Mechanical Properties of TiSnC (MAX) Thin Nanocrystalline Films and Powdered Polycrystalline Samples.

Layered ternary TiSnC carbides have attracted significant attention because of their advantage as a M2AX phase to bridge the gap between properties of metals and ceramics. In this study, TiSnC materials were synthesized by two different methods-an unconventional low-energy ion facility (LEIF) based on Ar ion beam sputtering of the Ti, Sn, and C targets and sintering of a compressed mixture consisting of Ti, Sn, and C elemental powders up to 1250 °C. The TiSnC nanocrystalline thin films obtained by LEIF were irradiated by Ar ions with an energy of 30 keV to the fluence of 1.

Hydroxyapatite as a scavenger of reactive radiolysis species in graphene liquid cells forelectron microscopy.

Liquid cell electron microscopy is an imaging technique allowing for the investigation of the interaction of liquids and solids at nanoscopic length scales. Suchobservations are increasingly in-demand in an array of fields, from biological sciences to medicine to batteries. Graphene liquid cells (GLCs), in particular, have generated a great interest as a low-scattering window material with the potential for increasing the quality of both imaging and spectroscopy.

Control of crystal size tailors the electrochemical performance of α-VO as a Mg intercalation host.

α-VO has been extensively explored as a Mg intercalation host with potential as a battery cathode, offering high theoretical capacities and potentials vs. Mg/Mg. However, large voltage hysteresis is observed with Mg insertion and extraction, introducing significant and unacceptable round-trip energy losses with cycling.

Dynamically Stable Active Sites from Surface Evolution of Perovskite Materials during the Oxygen Evolution Reaction.

Perovskite oxides are an important class of oxygen evolution reaction (OER) catalysts in alkaline media, despite the elusive nature of their active sites. Here, we demonstrate that the origin of the OER activity in a LaSrCoO model perovskite arises from a thin surface layer of Co hydr(oxy)oxide (CoOH) that interacts with trace-level Fe species present in the electrolyte, creating dynamically stable active sites. Generation of the hydr(oxy)oxide layer is a consequence of a surface evolution process driven by the A-site dissolution and O-vacancy creation.

Enhanced charge storage of nanometric ζ-VO in Mg electrolytes.

V2O5 is of interest as a Mg intercalation electrode material for Mg batteries, both in its thermodynamically stable layered polymorph (α-V2O5) and in its metastable tunnel structure (ζ-V2O5). However, such oxide cathodes typically display poor Mg insertion/removal kinetics, with large voltage hysteresis. Herein, we report the synthesis and evaluation of nanosized (ca.

Highly Conductive Collagen by Low-Temperature Atomic Layer Deposition of Platinum.

In modern biomaterial-based electronics, conductive and flexible biomaterials are gaining increasing attention for their wide range of applications in biomedical and wearable electronics industries. The ecofriendly, biodegradable, and self-resorbable nature of these materials makes them an excellent choice in fabricating green and transient electronics. Surface functionalization of these biomaterials is required to cater to the need of designing electronics based on these substrate materials.

Probing Mg Intercalation in the Tetragonal Tungsten Bronze Framework VNbO.

While commercial Li-ion batteries offer the highest energy densities of current rechargeable battery technologies, their energy storage limit has almost been achieved. Therefore, there is considerable interest in Mg batteries, which could offer increased energy densities in comparison to Li-ion batteries if a high-voltage electrode material, such as a transition-metal oxide, can be developed. However, there are currently very few oxide materials which have demonstrated reversible and efficient Mg insertion and extraction at high voltages; this is thought to be due to poor Mg diffusion kinetics within the oxide structural framework.

Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes.

Versatile chemical transformations of surface functional groups in two-dimensional transition-metal carbides (MXenes) open up a previously unexplored design space for this broad class of functional materials. We introduce a general strategy to install and remove surface groups by performing substitution and elimination reactions in molten inorganic salts. Successful synthesis of MXenes with oxygen, imido, sulfur, chlorine, selenium, bromine, and tellurium surface terminations, as well as bare MXenes (no surface termination), was demonstrated.

Quasi-Binary Transition Metal Dichalcogenide Alloys: Thermodynamic Stability Prediction, Scalable Synthesis, and Application.

Transition metal dichalcogenide (TMDCs) alloys could have a wide range of physical and chemical properties, ranging from charge density waves to superconductivity and electrochemical activities. While many exciting behaviors of unary TMDCs have been demonstrated, the vast compositional space of TMDC alloys has remained largely unexplored due to the lack of understanding regarding their stability when accommodating different cations or chalcogens in a single-phase. Here, a theory-guided synthesis approach is reported to achieve unexplored quasi-binary TMDC alloys through computationally predicted stability maps.

Hydrolyzed Ce(IV) salts limit sucrose-dependent biofilm formation by Streptococcus mutans.

Several studies have focused on the antimicrobial effects of cerium oxide nanoparticles (CeO-NP) but few have focused on their effects on bacteria under initial biofilm formation conditions. Streptococcus mutans is a prolific biofilm former contributing to dental caries in the presence of fermentable carbohydrates and is a recognized target for therapeutic intervention. CeO-NP derived solely from Ce(IV) salt hydrolysis were found to reduce adherent bacteria by approximately 40% while commercial dispersions of "bare" CeO-NP (e.