Structural Design Principle of Rocksalt Oxides for Li-Excess Cathode Materials.

Li-excess oxide cathodes have received increasing attention due to their high capacity derived from accumulated cation and anion redox activity. However, Li-excess layered oxides suffer from capacity and voltage decay due to the irreversible phase transition, while cation-disordered cathodes also have the problems of poor cycling stability and rate capability. The rocksalt oxides with a layered-disordered coexistence nanostructure can combine the advantages of both phases such as the inherent high capacity of Li-excess oxides, good rate capability of the layered phase, and structural stability resulting from the intergrown disordered phase.

Enhancing anionic redox stability oxygen coordination configurations.

Anionic redox in Li-rich cathode materials with disordered crystal structures has potential to increase battery energy density. However, capacity fading due to anionic redox-induced structural transformation hinders practical implementation. To address this challenge, it is crucial to understand the influence of the anion coordination structure on redox reversibility.

Trinitroaromatic Salts as High-Energy-Density Organic Cathode Materials for Li-Ion Batteries.

Even though organic molecules with designed structures can be assembled into high-capacity electrode materials, only limited functional groups such as -C═O and -C═N- could be designed as high-voltage cathode materials with enough high capacity. Here, we propose a common chemical raw material, trinitroaromatic salt, to have promising potential to develop organic cathode materials with high discharge voltage and capacity through a strong delocalization effect between -NO and aromatic ring. Our first-principles calculations show that electrochemical reactions of trinitroaromatic potassium salt CH(NO)OK are a 6-electron charge-transfer process, providing a high discharge capacity of 606 mAh g and two voltage plateaus of 2.

Hydrogenated Germanene Nanosheets as an Antioxidative Defense Agent for Acute Kidney Injury Treatment.

Acute kidney injury (AKI) is a sudden kidney dysfunction caused by aberrant reactive oxygen species (ROS) metabolism that results in high clinical mortality. The rapid development of ROS scavengers provides new opportunities for AKI treatment. Herein, the use of hydrogen-terminated germanene (H-germanene) nanosheets is reported as an antioxidative defense nanoplatform against AKI in mice.

Water-Enabled H Generation from Hydrogenated Silicon Nanosheets for Efficient Anti-Inflammation.

As an emerging therapeutic gas, hydrogen (H) is gifted with excellent biosafety, high tissue permeability, and radical-trapping capacity and is extensively considered as a highly promising antioxidant in clinics. However, a facile and effective strategy of H production for major inflammatory disease treatments is still lacking. In this study, by a facile wet-chemical exfoliation synthesis, a hydrogen-terminated silicon nanosheet (H-silicene) has been synthesized, which can favorably react with environmental water to generate H rapidly and continuously without any external energy input.

Triple Conductive Wiring by Electron Doping, Chelation Coating and Electrochemical Conversion in Fluffy Nb O Anodes for Fast-Charging Li-Ion Batteries.

High-rate anode material is the kernel of developing fast-charging lithium ion batteries (LIBs). T-Nb O , well-known for its "room and pillar" structure and bulk pseudocapacitive effect, is expected to enable the fast lithium (de)intercalation. But this property is still limited by the low electronic conductivity or insufficient wiring manner.

lncR26319/miR-2834/EndophilinA axis regulates oogenesis of the silkworm, Bombyx mori.

Oocyte maturation is critical for insect reproduction. Vitellogenesis, the timely production and uptake of vitellogenin (Vg), is crucial for female fecundity. Vg is synthesized in fat body and absorbed by the oocytes through endocytosis during insect oogenesis.

Origin of multiple voltage plateaus in P2-type sodium layered oxides.

Although layered transition metal (TM) oxides have attracted considerable attention for cathode materials of sodium-ion batteries, they suffer from uncontrolled multiple voltage plateaus due to local structure transformations such as TM-layer gliding and Na/vacancy ordering upon Na extraction and insertion. However, the intrinsic origins of these local structure transformations are not fully understood, preventing the rational design of better cathode materials. Here, we concentrate on Na/vacancy ordering in single phase domains to reveal the underlying mechanism of multiple voltage plateaus by tracking desodiation-induced electronic structure evolutions of two typical compounds, P2-Na[CrTi]O and P2-NaCrO.

Hydrogen-bonded silicene nanosheets of engineered bandgap and selective degradability for photodynamic therapy.

Silicon, a highly biocompatible and ubiquitous chemical element in living systems, exhibits great potentials in biomedical applications. However, the silicon-based nanomaterials such as silica and porous silicon have been largely limited to only serving as carriers for delivery systems, due to the lack of intrinsic functionalities of silicon. This work presents the facile construction of a two-dimensional (2D) hydrogen-bonded silicene (H-silicene) nanosystem which is highlighted with tunable bandgap and selective degradability for tumor-specific photodynamic therapy facilely by surface covalent modification of hydrogen atoms.

Enhanced Thermoelectric Performance in Ge Sb Te/FeGe Composites Enabled by Hierarchical Defects.

Manipulations of carrier and phonon scatterings through hierarchical structures have been proved to be effective in improving thermoelectric performance. Previous efforts in GeTe-based materials mainly focus on simultaneously optimizing the carrier concentration and band structure. In this work, a synergistic strategy to tailor thermal and electrical transport properties of GeTe by combination with the scattering effects from both Ge vacancies and other defects is reported.

Identifying Metallic Transition-Metal Dichalcogenides for Hydrogen Evolution through Multilevel High-Throughput Calculations and Machine Learning.

High-performance electrocatalysts not only exhibit high catalytic activity but also have sufficient thermodynamic stability and electronic conductivity. Although metallic 1T-phase MoS and WS have been successfully identified to have high activity for hydrogen evolution reaction, designing more extensive metallic transition-metal dichalcogenides (TMDs) faces a large challenge because of the lack of a full understanding of electronic and composition attributes related to catalytic activity. In this work, we carried out systematic high-throughput calculation screening for all possible existing two-dimensional TMD (2D-TMD) materials to obtain high-performance hydrogen evolution reaction (HER) electrocatalysts by using a few important criteria, such as zero band gap, highest thermodynamic stability among available phases, low vacancy formation energy, and approximately zero hydrogen adsorption energy.

The order-disorder transition in CuSe and medium-range ordering in the high-temperature phase.

The high thermoelectric performance of cuprous selenide (CuSe) arises from its specific structures consisting of two independent sublattices, i.e. the rigid face-centered cubic (f.

Stabilizing Low-Coordinated O Ions To Operate Cationic and Anionic Redox Chemistry of Li-Ion Battery Materials.

Conventional electrochemical processes are mainly operated by cationic redox chemistry. Developing cumulative cationic and anionic redox chemistry offers a transformative approach to increase the energy storage capacity of Li-ion batteries and active sites of catalysts. However, realizing the reversible anionic redox reaction to increase the specific capacity in Li-ion battery materials is a large challenge because uncontrollable anion-anion combination and gas evolutions cause poor cyclic performance.

Silicene: Wet-Chemical Exfoliation Synthesis and Biodegradable Tumor Nanomedicine.

Silicon-based biomaterials play an indispensable role in biomedical engineering; however, due to the lack of intrinsic functionalities of silicon, the applications of silicon-based nanomaterials are largely limited to only serving as carriers for drug delivery systems. Meanwhile, the intrinsically poor biodegradation nature for silicon-based biomaterials as typical inorganic materials also impedes their further in vivo biomedical use and clinical translation. Herein, by the rational design and wet chemical exfoliation synthesis of the 2D silicene nanosheets, traditional 0D nanoparticulate nanosystems are transformed into 2D material systems, silicene nanosheets (SNSs), which feature an intriguing physiochemical nature for photo-triggered therapeutics and diagnostic imaging and greatly favorable biological effects of biocompatibility and biodegradation.

Small nucleolar RNA Sf-15 regulates proliferation and apoptosis of Spodoptera frugiperda Sf9 cells.

Background: Small nucleolar RNAs (snoRNAs) function in guiding 2'-O-methylation and pseudouridylation of ribosomal RNAs (rRNAs) and small nuclear RNAs (snRNAs). In recent years, more and more snoRNAs have been found to play novel roles in mRNA regulation, such as pre-mRNA splicing or RNA editing. In our previous study, we found a silkworm C/D box snoRNA Bm-15 can interact with Notch receptor gene in vitro.

Identification and functional characterization of intermediate-size non-coding RNAs in maize.

Background: The majority of eukaryote genomes can be actively transcribed into non-coding RNAs (ncRNAs), which are functionally important in development and evolution. In the study of maize, an important crop for both humans and animals, aside from microRNAs and long non-coding RNAs, few studies have been conducted on intermediate-size ncRNAs.

Results: We constructed a homogenized cDNA library of 50-500 nt RNAs in the maize inbred line Chang 7-2.

Auto-optimizing Hydrogen Evolution Catalytic Activity of ReS through Intrinsic Charge Engineering.

Optimizing active electronic states responding to catalysis is of paramount importance for developing high-activity catalysts because thermodynamics itself may not favor forming an optimal electronic state. Setting the monolayer transition metal dichalcogenide (TMD) ReS as a model for the hydrogen evolution reaction (HER), we uncover that intrinsic charge engineering has an auto-optimizing effect on enhancing catalytic activity through regulating active electronic states. The experimental and theoretical results show that intrinsic charge compensation from S to Re-Re bonds could manipulate the active electronic states, allowing hydrogen to absorb the active sites neither strongly nor weakly.

Superposed Redox Chemistry of Fused Carbon Rings in Cyclooctatetraene-Based Organic Molecules for High-Voltage and High-Capacity Cathodes.

Even though many organic cathodes have been developed and have made a significant improvement in energy density and reversibility, some organic materials always generate relatively low voltage and limited discharge capacity because their energy storage mechanism is solely based on redox reactions of limited functional groups [N-O, C═X (X = O, N, S)] linking to aromatic rings. Here, a series of cyclooctatetraene-based (CH) organic molecules were demonstrated to have electrochemical activity of high-capacity and high-voltage from carbon rings by means of first-principles calculations and electronic structure analysis. Fused molecules of C-C-C (CH) and C-C-C-C-C (CH) contain, respectively, four and eight electron-deficient carbons, generating high-capacity by their multiple redox reactions.

Structure family and polymorphous phase transition in the compounds with soft sublattice: Cu2Se as an example.

Quite a few interesting but controversial phenomena, such as simple chemical composition but complex structures, well-defined high-temperature cubic structure but intriguing phase transition, coexist in Cu2Se, originating from the relatively rigid Se framework and "soft" Cu sublattice. However, the electrical transport properties are almost uninfluenced by such complex substructures, which make Cu2Se a promising high-performance thermoelectric compound with extremely low thermal conductivity and good power factor. Our work reveals that the crystal structure of Cu2Se at the temperature below the phase-transition point (∼400 K) should have a group of candidate structures that all contain a Se-dominated face-centered-cubic-like layered framework but nearly random site occupancy of atoms from the "soft" Cu sublattice.

Diverse lattice dynamics in ternary Cu-Sb-Se compounds.

Searching and designing materials with extremely low lattice thermal conductivity (LTC) has attracted considerable attention in material sciences. Here we systematically demonstrate the diverse lattice dynamics of the ternary Cu-Sb-Se compounds due to the different chemical-bond environments. For Cu3SbSe4 and CuSbSe2, the chemical bond strength is nearly equally distributed in crystalline bulk, and all the atoms are constrained to be around their equilibrium positions.

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy.

Understanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectric materials, which usually requires an extremely low lattice thermal conductivity (LTC). By analyzing the finite-temperature structural and vibrational characteristics of typical thermoelectric compounds such as filled skutterudites and Cu3SbSe3, we demonstrate a concept of part-crystalline part-liquid state in the compounds with chemical-bond hierarchy, in which certain constituent species weakly bond to other part of the crystal. Such a material could intrinsically manifest the coexistence of rigid crystalline sublattices and other fluctuating noncrystalline sublattices with thermally induced large-amplitude vibrations and even flow of the group of species atoms, leading to atomic-level heterogeneity, mixed part-crystalline part-liquid structure, and thus rattling-like thermal damping due to the collective soft-mode vibrations similar to the Boson peak in amorphous materials.

Polytypism in superhard transition-metal triborides.

The quest of novel compounds with special structures and unusual functionalities continues to be a central challenge to modern materials science. Even though their exact structures have puzzled scientists for decades, superhard transition-metal borides (TMBs) have long been believed to exist only in simple crystal structures. Here, we report on a polytypic phenomenon in superhard WB3 and MoB3 with a series of energetically degenerate structures due to the random stacking of metal layers amongst the interlocking boron layers.