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Li-air batteries are considered strong candidates for the next-generation energy storage systems designed for electrical transportation. However, low cyclability and current rates are two major drawbacks that hinder them from further realization. These issues necessitate the discovery of novel materials to significantly enhance the redox process of discharge products. In this study, a novel catalytic system comprised of tin sulfide (SnS) nanoflakes as a solid catalyst and tin iodide (SnI2) as a dual-functional electrolyte additive is discovered. This system enables operating the battery at high current rates up to 10 000 mA g−1 (corresponding to 1 mA cm−2). The SnS catalyst shows outstanding catalytic activity for both oxygen reduction and evolution reactions compared to carbon, noble metals, and other transition metal dichalcogenides. It also exhibits good structural integrity at high rates. The computations indicate numerous possible oxygen reduction sites without oxygen dissociations on the SnS surface through solution mechanism that is likely responsible for the formation of Li2O2. The calculations also indicate that the role of the SnI2 is not only reacting with the lithium anode to provide protection but reducing the charge potential by promoting catalytic decomposition of the Li2O2. This work provides new novel additives for designing high-rate Li-air batteries.

The rechargeable lithium-oxygen (Li-O

Temperature coefficients (TCs) for either electrochemical cell voltages or potentials of individual electrodes have been widely utilized to study the thermal safety and cathode/anode phase changes of lithium (Li)-ion batteries. However, the fundamental significance of single electrode potential TCs is little known. In this work, we discover that the Li-ion desolvation process during Li deposition/intercalation is accompanied by considerable entropy change, which significantly contributes to the measured Li/Li+ electrode potential TCs. To explore this phenomenon, we compare the Li/Li+ electrode potential TCs in a series of electrolyte formulations, where the interaction between Li-ion and solvent molecules occurs at varying strength as a function of both solvent and anion species as well as salt concentrations. As a result, we establish correlations between electrode potential TCs and Li-ion solvation structures and further verify them by ab initio molecular dynamics simulations. We show that measurements of Li/Li+ electrode potential TCs provide valuable knowledge regarding the Li-ion solvation environments and could serve as a screening tool when designing future electrolytes for Li-ion/Li metal batteries.

Stable operation of rechargeable lithium-based batteries at low temperatures is important for cold-climate applications, but is plagued by dendritic Li plating and unstable solid–electrolyte interphase (SEI). Here, we report on high-performance Li metal batteries under low-temperature and high-rate-charging conditions. The high performance is achieved by using a self-assembled monolayer of electrochemically active molecules on current collectors that regulates the nanostructure and composition of the SEI and deposition morphology of Li metal anodes. A multilayer SEI that contains a lithium fluoride-rich inner phase and amorphous outer layer effectively seals the Li surface, in contrast to the conventional SEI, which is non-passive at low temperatures. Consequently, galvanic Li corrosion and self-discharge are suppressed, stable Li deposition is achieved from −60 °C to 45 °C, and a Li | LiCoO2 cell with a capacity of 2.0 mAh cm−2 displays a 200-cycle life at −15 °C with a recharge time of 45 min. In addition to high energy, batteries need to possess high power and to be able to operate in all climates. Here, the authors present an electrochemically active monolayer-coated current collector that is used to produce high-performance Li metal batteries under low-temperature and high-rate-charging conditions.

For the past three decades, the coordination-driven self-assembly of three-dimensional structures has undergone rapid progress; however, parallel efforts to create large discrete two-dimensional architectures—as opposed to polymers—have met with limited success. The synthesis of metallo-supramolecular systems with well-defined shapes and sizes in the range of 10–100 nm remains challenging. Here we report the construction of a series of giant supramolecular hexagonal grids, with diameters on the order of 20 nm and molecular weights greater than 65 kDa, through a combination of intra- and intermolecular metal-mediated self-assembly steps. The hexagonal intermediates and the resulting self-assembled grid architectures were imaged at submolecular resolution by scanning tunnelling microscopy. Characterization (including by scanning tunnelling spectroscopy) enabled the unambiguous atomic-scale determination of fourteen hexagonal grid isomers. Metal-mediated self-assembly in solution typically leads to small two- and three-dimensional architectures on scales smaller than 10 nm, but now a series of large, discrete, two-dimensional supramolecular hexagonal grids have been prepared through a combination of intra- and intermolecular coordination interactions. These 20-nm-wide grids have been imaged at submolecular resolution using scanning tunnelling microscopy.

Redox mediators (RMs) are solution-based additives that have been extensively used to reduce the charge potential and increase the energy efficiency of Li-oxygen (Li-O

5-InsP7 is an endogenous negative regulator of Na+/K+-ATPase., Sodium/potassium-transporting adenosine triphosphatase (Na+/K+-ATPase) is one of the most abundant cell membrane proteins and is essential for eukaryotes. Endogenous negative regulators have long been postulated to play an important role in regulating the activity and stability of Na+/K+-ATPase, but characterization of these regulators has been elusive. Mechanisms of regulating Na+/K+-ATPase homeostatic turnover are unknown. Here, we report that 5-diphosphoinositol 1,2,3,4,6-pentakisphosphate (5-InsP7), generated by inositol hexakisphosphate kinase 1 (IP6K1), promotes physiological endocytosis and downstream degradation of Na+/K+-ATPase-α1. Deletion of IP6K1 elicits a twofold enrichment of Na+/K+-ATPase-α1 in plasma membranes of multiple tissues and cell types. Using a suite of synthetic chemical biology tools, we found that 5-InsP7 binds the RhoGAP domain of phosphatidylinositol 3-kinase (PI3K) p85α to disinhibit its interaction with Na+/K+-ATPase-α1. This recruits adaptor protein 2 (AP2) and triggers the clathrin-mediated endocytosis of Na+/K+-ATPase-α1. Our study identifies 5-InsP7 as an endogenous negative regulator of Na+/K+-ATPase-α1.

From dictating the redox potential of electrolyte solvents to shaping the stability of solid-electrolyte interfaces, solvation plays a critical role in the electrochemistry of electrolytes. To efficiently design functional electrolytes for lithium batteries, it is particularly important to understand the relative solvating ability of each individual organic solvent, because most of the electrolyte systems are comprised of two or more electrolyte solvents. Using a newly developed internally referenced diffusion-ordered spectroscopy technique and diffusion coefficient–coordination ratio (D–α) analysis, we successfully constructed a solvating power series for common electrolyte solvents. We demonstrated the usefulness of this solvating power series in designing more reliable electrolyte system by selecting an appropriate fluorinated electrolyte solvent for a high-voltage lithium metal battery (LMB) as an example. For a methyl(2,2,2-trifluoroethyl)carbonate-based electrolyte, we identified fluoroethylene carbonate as a more desirable cyclic carbonate co-solvent than difluoroethylene carbonate for LMB due to its significantly higher ability to solvate lithium ions.

Inositol hexakisphosphate kinase-1 (IP6K1) is required for male fertility, but the underlying mechanisms have been elusive. Here, we report that IP6K1 is required for multiple aspects of male germ cell development. This development requires selective interactions between germ cells and Sertoli cells, namely apical ectoplasmic specialization. Spermiation (sperm release) requires tubulobulbar complexes. We found that the apical ectoplasmic specialization and tubulobulbar complexes were poorly formed or disrupted in IP6K1 KOs. Deletion of IP6K1 elicited several aberrations, including: 1, sloughing off of round germ cells; 2, disorientation and malformation of elongating/elongated spermatids; 3, degeneration of acrosomes; 4, defects in germ-Sertoli cell interactions and 5, failure of spermiation. Eventually the sperm cells were not released but phagocytosed by Sertoli cells leading to an absence of sperm in the epididymis.

Understanding the decaying mechanism in lithium-ion batteries (LIBs) is critical to establishing a stable electrolyte system. Despite the advent of various novel electrolyte solvents designated for high-voltage LIBs, their working principles are not fully understood. Currently, oxidative decomposition of electrolytes is believed to be the major cause of capacity fade, and tremendous effort has been devoted to discovering a new electrolyte with enhanced anodic stability. However, the oxidative decomposition process cannot solely explain the rapid decay of some electrolyte systems with intrinsic high anodic stability when used with a high-nickel layered oxide cathode such as LiNi0.6Mn0.2Co0.2O2 (NMC622). In this report, a study of the quantitative structure-activity relationship was conducted to deepen the mechanistic understanding of the decay in high-voltage LIBs. The results obtained from the newly introduced molecular pair analysis and linear free-energy relationship (LFER) studies were highly consistent with the solvation-involved decaying mechanism in a high-nickel layered oxide cathode cycling at high voltage (> 4.5 V vs. Li/Li+). There was no evidence correlating the solvation ability of electrolyte solvents with the decay of a high-nickel layered oxide cathode cycling at a relatively low voltage (

In comparing knotted versus knotless anchors for labral repair in the shoulder, there are no significant differences in clinical outcomes or biomechanical properties including load to failure.

Inositol hexakisphosphate kinase 1 (IP6K1), which generates 5-diphosphoinositol pentakisphosphate (5-IP7), physiologically mediates numerous functions. We report that IP6K1 deletion leads to brain malformation and abnormalities of neuronal migration. IP6K1 physiologically associates with α-actinin and localizes to focal adhesions. IP6K1 deletion disrupts α-actinin’s intracellular localization and function. The IP6K1 deleted cells display substantial decreases of stress fiber formation and impaired cell migration and spreading. Regulation of α-actinin by IP6K1 requires its kinase activity. Deletion of IP6K1 abolishes α-actinin tyrosine phosphorylation, which is known to be regulated by focal adhesion kinase (FAK). FAK phosphorylation is substantially decreased in IP6K1 deleted cells. 5-IP7, a product of IP6K1, promotes FAK autophosphorylation. Pharmacologic inhibition of IP6K by TNP [N2-(m-Trifluorobenzyl), N6-(p-nitrobenzyl)purine] recapitulates the phenotype of IP6K1 deletion. These findings establish that IP6K1 physiologically regulates neuronal migration by binding to α-actinin and influencing phosphorylation of both FAK and α-actinin through its product 5-IP7.

Cells express a family of three inositol hexakisphosphate kinases (IP6Ks). Although sharing the same enzymatic activity, individual IP6Ks mediate different cellular processes. Here we report that IP6K3 is enriched at the leading edge of migrating cells where it associates with dynein intermediate chain 2 (DIC2). Using immunofluorescence microscopy and total internal reflection fluorescence microscopy, we found that DIC2 and IP6K3 are recruited interdependently to the leading edge of migrating cells, where they function coordinately to enhance the turnover of focal adhesions. Deletion of IP6K3 causes defects in cell motility and neuronal dendritic growth, eventually leading to brain malformations. Our results reveal a mechanism whereby IP6K3 functions in coordination with DIC2 in a confined intracellular microenvironment to promote focal adhesion turnover.

We present a detailed analysis of the role of native point defects in the antiferromagnetic (AFM) phases of bulk chromium nitride (CrN). We perform first-principles calculations by using the local spin-density approximation, including local interaction effects $(\text{LSDA}+U)$, to study the two lowest energy AFM models expected to describe the low-temperature phase of the material. We study the formation energies, lattice deformations, and electronic and magnetic structure introduced by native point defects. We find that, as expected, nitrogen vacancies are the most likely defect present in the material at low temperatures. Nitrogen vacancies present different charged states in the cubic AFM model, exhibiting two transition energies, which could be measured by thermometry experiments and could help identify the AFM structure in a sample. These vacancies also result in partial spin polarization of the induced impurity band, which would have interesting consequences in experiments. Other point defects have also signature electronic and magnetic structure that could be identified in scanning probe experiments.

Rationale: Inositol polyphosphate multikinase (IPMK) and its major product inositol pentakisphosphate (IP5) regulate a variety of cellular functions, but their role in vascular biology remains unexplored. Objective: We have investigated the role of IPMK in regulating angiogenesis. Methods and Results: Deletion of IPMK in fibroblasts induces angiogenesis in both in vitro and in vivo models. IPMK deletion elicits a substantial increase of VEGF (vascular endothelial growth factor), which mediates the regulation of angiogenesis by IPMK. The regulation of VEGF by IPMK requires its catalytic activity. IPMK is predominantly nuclear and regulates gene transcription. However, IPMK does not apparently serve as a transcription factor for VEGF. HIF (hypoxia-inducible factor)-1α is a major determinant of angiogenesis and induces VEGF transcription. IPMK deletion elicits a major enrichment of HIF-1α protein and thus VEGF. HIF-1α is constitutively ubiquitinated by pVHL (von Hippel–Lindau protein) followed by proteasomal degradation under normal conditions. However, HIF-1α is not recognized and ubiquitinated by pVHL in IPMK KO (knockout) cells. IP5 reinstates the interaction of HIF-1α and pVHL. HIF-1α prolyl hydroxylation, which is prerequisite for pVHL recognition, is interrupted in IPMK-deleted cells. IP5 promotes HIF-1α prolyl hydroxylation and thus pVHL-dependent degradation of HIF-1α. Deletion of IPMK in mouse brain increases HIF-1α/VEGF levels and vascularization. The increased VEGF in IPMK KO disrupts blood–brain barrier and enhances brain blood vessel permeability. Conclusions: IPMK, via its product IP5, negatively regulates angiogenesis by inhibiting VEGF expression. IP5 acts by enhancing HIF-1α hydroxylation and thus pVHL-dependent degradation of HIF-1α.

We present a theoretical analysis of the role that strain plays on the electronic structure of chromium nitride (CrN) crystals. We use local spin-density approximation + $U$ calculations to study the elastic constants, deformation potentials, and strain dependence of electron and hole masses near the fundamental gap. We consider the lowest energy antiferromagnetic models believed to describe CrN at low temperatures, and apply strain along different directions. We find relatively large deformation potentials for all models, and find increasing gaps for tensile strain along most directions. Most interestingly, we find that compressive strains should be able to close the relatively small indirect gap $(\ensuremath{\simeq}100$ meV) at moderate amplitudes $\ensuremath{\simeq}1.3%$. We also find large and anisotropic changes in the effective masses with strain, with principal axes closely related to the magnetic ordering of neighboring layers in the antiferromagnet. It would be interesting to consider the role that these effects may have on typical film growth on different substrates, and the possibility of monitoring optical and transport properties of thin films as strain is applied.

Various organic compounds were investigated as co-solvents in an ionic liquid (IL), N,N-butylmethyl pyrrolidinium bis(trifluoromethylsulfonyl)imide (Pyr14TFSI), based electrolyte for Li-S batteries. For the Pyr14TFSI/Co-solvent binary system, only 1,3-dioxolane (DOL) afforded stable cycling performance with reasonable Coulombic efficiency (CE). Further increase in DOL concentration leads to a higher initial capacity but deteriorated CE. In an attempt to balance CE and capacity, 2.0 M LiTFSI Pyr14TFSI/DOL (2:1) exhibited optimal performance in terms of initial discharge capacity of 896 mAhg−1 and CE of 98.1% for over 200 cycle. The role of DOL and salt concentration interplay in the binary electrolyte was simulated by ab-initio molecular dynamics (AIMD). The solvation energy with varying co-solvent and LiTFSI salt concentration provides useful information when looking toward implementing other IL-based electrolyte systems for Li-S chemistry.

Seven partially fluorinated ethers (PFE) were studied as co-solvents for lithium-sulfur battery with the goal to understand the interplay between the molecular structure and the electrochemical properties, including capacity, Coulombic efficiency and SEI formation on the Li anode. Electrochemical cycling indicates a loose correlation between the Coulombic efficiency observed over 200 cycles and the fluorination degree of the PFE, which correlates with the computed pKa of the C–H bond of the ethers. PFE with lower pKa (

The adsorption characteristics of the sexithiophene (6T) molecule on Ag(110) are studied using density functional theory with the inclusion of van der Waals (vdW) interactions. The stable adsorption configurations on 6T on Ag(110) as well as the nature of bonding the Ag substrate are evaluated. We also assess the performance of the vdW-DF method in describing the adsorption, energetics, heights, as well as the interface characteristics with the Ag(110) surface. We find two lowest adsorption energy configurations, at which the 6T molecule aligns with its molecular long axis parallel and perpendicular to the [001] direction, to be energetically close to each other, suggesting that they may coexist. Our findings indicate a significant increase in the 6T adsorption energies upon the inclusion of vdW interactions with the highest increase obtained using the opt-type functionals, in particular with the optB86b-vdW functional. The revPBE-vdW and rPW86-vdW2 functionals lead to less enhancement in adsorption energies that is attributed to the strong repulsive nature of these functionals, in agreement with earlier predictions. Upon adsorption of the 6T molecule, the changes in the atomic and electronic structures of the 6T molecule and Ag surface are found to be negligible; there is no charge transfer, and no interface state is observed. The work function is reduced upon adsorption with the largest change is ~0.6 eV obtained using the optB88-vdW functional. The results are in good agreement with the available experimental observations of the adsorption configurations and the work function changes. Based on our results, we conclude that the nature of bonding for 6T on Ag(110) can be classified as strong physisorption.

We apply density functional theory, with and without the inclusion of self-consistent van der Waals (vdWs) interactions (optB86, optB88, optPBE, revPBE, rPW86), to study the adsorption of thiophene (C4H4S) on Cu(100) and Ni(100). Our calculations reveal that the C4H4S molecule adsorbs, on either substrate, with its molecular plane parallel to the surface with the sulfur close to the bridge site. The inclusion of vdWs interactions results in a significant increase in the binding energy of thiophene on Cu(100) (from 0.12 eV to up to 0.77 eV), while the adsorption height is also modified from 3.2 A down to, at most, 2.38 A, depending on the functional used. The Ni(100) case presents a similar behavior for the binding energy (enhancement from 1.56 eV to up to 2.34 eV), but the adsorption heights increase from 2.12 Å up to 2.32 Å. In addition to adsorption geometry and energetics, we present the results and analysis of the electronic properties (charge transfer, changes in the d-band of the substrate, and change in the work function) of these two systems to complement our understanding of the molecule-substrate bonding. Our results suggest that the adsorption characteristics are dependent on the type of functional used; opt-type functionals (optB86, optB88, optPBE) are found to produce stronger bonding as compared to PBE, revPBE and rPW86. This work is funded by the U.S. Department of Energy Basic Energy Science under Contract No DE-FG02-11ER16243

We use density functional theory to study the adsorption of Sexithiophene (6T) on Ag(110). Special attention is given for exploring the effects of van der Waals interactions on the adsorption geometry and energy using vdW-DF family functionals. The 6T molecule is found to bind to the Ag(110) surface via two orientations, with the long molecular axis parallel to the [001] and [110] directions. Including van der Waals interactions resulted in a substantial increase in the binding energy (from 0.6 eV to 4 eV), while the binding height is slightly modified (from 3.1 Å to 2.75 Å). Both the binding energies and heights show significant variations depending on the vdW functional used: the opt-type functionals (optB86, optB88, optPBE) further enhance the adsorption energy when compared to those obtained using PBE, revPBE, or rPW86 functionals. Upon adsorption, there is a small, however, noticeable broadening and a shift (towards higher binding energy) in the position of the d-band center of the substrate surface atoms is observed. Note that, the absence of charge transfer, interfacial states, changes in the atomic structure of the molecule or the substrate suggests that the bonding characteristic of the 6T/Ag(110) system can be categorized as weak chemisorption or strong physisorption. This work is funded by the U.S. Department of Energy Basic Energy Science under Contract No DE-FG02-11ER16243