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In this work, nano LiV3O8(LVO) was synthesized using the rheological phase reaction method. Subsequently, after ultrasonic and heat treatment at 300 °C, the nano LVO Ut-300 was obtained and performed as cathode material in Na-ion batteries for the first time. Brunauer–Emmett–Teller analysis indicated that the specific area increased after ultrasonic treatment, which was conducive to the shuttling of sodium ions and enhancement of the electrochemical performance. The X-ray diffraction patterns displayed stable nano LVO Ut-300 material structure and larger interlayer spacing, and SEM and TEM performed more regular morphology. After the electrochemical tests, the nano LVO Ut-300 cathode delivered a high discharge capacity of 153.8 mA h g–1 in the voltage range of 1.8–4.0 V at 30 mA g–1. Meanwhile, the storage mechanism of Na+ was further explored by XPS, and kinetics characteristics of LVO/Na cells were revealed by pseudocapacitance analysis and galvanostatic intermittent titration technique (GITT) tests. In summary, nano LVO was processed by the ultrasonic method followed by subsequent heat treatment, which could effectively improve the electrochemical behavior of LiV3O8 as cathode materials of secondary Na-ion batteries. [ABSTRACT FROM AUTHOR]

The electrochemical properties ofNa3V2(PO4)2F3cathode utilized in the sodiumion battery are investigated, and the ion migration mechanisms areproposed as combined via the first principles calculations. Two differentNa sites, namely, the Na(1) and Na(2) sites, could cause two sodiumions of Na3V2(PO4)2F3to be extracted or inserted by a two-step electrochemicalprocess accompanied by structural reorganization that could be responsiblefor the redox reaction of V3+/4+. Because the calculatedaverage voltage (Vavg) of the second chargingplateau is 4.04 V for the optimized system but 4.38 V for the unoptimizedone, the reorganization of the cathode system can make a stable configurationand lower the extraction energy. Three designed pathways for sodiumions along the x, y, zdirections in Na3V2(PO4)2F3, known as a 3D ions transport tunnel, have activationenergies (Ea) of 0.449, 0.2, and 0.323eV, respectively, by using DFT calculations, demonstrating the differentfeasibilities of the migration directions. [ABSTRACT FROM AUTHOR]

The effect of surfactant, polymer, and tailor-made additives on the crystallization of γ-aminobutyric acid (GABA) was studied in this work. Cooling crystallization of GABA in water yielded plate-like crystals. In the presence of sodium stearate, polyhedral block-like crystals of GABA were obtained. Hydroxyethyl cellulose (HEC) led to rod-like crystals, in which the morphology was associated with additive concentrations. Six kinds of amino acids were used as tailor-made additives, and they exhibit different influences on crystal shape and size. The induction time of GABA was determined in the absence and presence of additives. The results showed that sodium stearate promoted nucleation, while HEC, l-Lysine, l-histidine, and l-tyrosine inhibited nucleation. Crystal face indexing, Hirshfeld surface analysis, and molecular dynamics (MD) simulation in aqueous solution-crystal systems were carried out to investigate the affecting factors of different crystal faces. The polymer additive was selected as an example during MD simulation to calculate intermolecular interactions between the crystal face and solvent or additive. The effect of the additive on the mobility of the solute in solution was also evaluated by mean-square displacement. The additive offers an effective approach for changing crystal morphology and particle size and adapting it to different production requirements., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Transition metal selenides have received considerable attention as promising candidates for lithium-ion battery (LIB) anode materials due to their high theoretical capacity and safety characteristics. However, their commercial viability is hampered by insufficient conductivity and volumetric fluctuations during cycling. To address these issues, we have utilized bimetallic metal-organic frameworks to fabricate CoNiSe 2 /C nanodecahedral composites with a high specific surface area, abundant pore structures, and a surface-coated layer of the carbon-based matrix. The optimized material, CoNiSe 2 /C-700, exhibited impressive Li + storage performance with an initial discharge specific capacity of 2125.5 mA h g -1 at 0.1 A g -1 and a Coulombic efficiency of 98% over cycles. Even after 1000 cycles at 1.0 A g -1 , a reversible discharge specific capacity of 549.9 mA h g -1 was achieved. The research highlights the synergistic effect of bimetallic selenides, well-defined nanodecahedral structures, stable carbon networks, and the formation of smaller particles during initial cycling, all of which contribute to improved electronic performance, reduced volume change, increased Li + storage active sites, and shorter Li + diffusion paths. In addition, the pseudocapacitance behavior contributes significantly to the high energy storage of Li + . These features facilitate rapid charge transfer and help maintain a stable solid-electrolyte interphase layer, which ultimately leads to an excellent electrochemical performance. This work provides a viable approach for fabricating bimetallic selenides as anode materials for high-performance LIBs through architectural engineering and compositional tailoring.

Molybdenum diselenide (MoSe 2 ) has been considered as promising electrocatalysts for catalyzing the hydrogen evolution reaction (HER) due to its narrow band gap and appropriate adsorption free energy. However, its catalytic performance is still impeded by inferior electrical conductivity and insufficient active sites, thus leading to unsatisfactory HER performance. Herein, MoSe 2 @N-doped carbon (NC) hollow nanoflowers with interfacial Mo-N-C bonds were controllably fabricated through the in situ selenization of the self-polymerized Mo-polydopamine precursor. Benefiting from the unique hollow structure, NC protective layer, and intimate interfacial interaction, the optimal MoSe 2 @NC displays good HER performance with low overpotentials (175 and 183 mV) and long-term stability (up to 12 h at -10 mA cm -2 ) in 0.5 M H 2 SO 4 and 1.0 M KOH solutions, respectively. The theoretical results show that Mo-N-C bonds at the interface of MoSe 2 @NC give rise to relatively low unoccupied e g orbital density of states and ideal H 2 adsorption free energy. This work presented here highlights the critical role of interfacial chemical bonds in regulating the electronic structure of nanomaterials and further improving the HER performance.

The low electronic conductivity of spinel-structured Li 4 Ti 5 O 12 could be improved by introducing CuV 2 O 6 . Herein, several Li 4 Ti 5 O 12 /CuV 2 O 6 composites with different CuV 2 O 6 contents have been successfully prepared by a facile liquid-phase dispersion technique. The amount of CuV 2 O 6 in composites is shown to affect the particle size and electrochemical performances of Li 4 Ti 5 O 12 . The Li 4 Ti 5 O 12 /CuV 2 O 6 composite prepared with a 5 wt % CuV 2 O 6 content (referred to as 5 wt % Li 4 Ti 5 O 12 /CuV 2 O 6 ) exhibits the best electrochemical performances among all the Li 4 Ti 5 O 12 /CuV 2 O 6 composites. The initial discharge/charge capacities of the 5 wt % Li 4 Ti 5 O 12 /CuV 2 O 6 composite reach 241.1/199.8 mAh g -1 and retain at 136.8/135.7 mAh g -1 over 500 cycles at 30 mA g -1 between 1.0 and 3.0 V. In addition, initial discharge/charge capacities of the 5 wt % Li 4 Ti 5 O 12 /CuV 2 O 6 composite amount to 129.8/90.5 mAh g -1 even at 1200 mA g -1 with maintained discharge/charge capacities of 71.1/71.1 mAh g -1 over 2500 cycles, which are superior to the pristine Li 4 Ti 5 O 12 in all cases. The detailed electrode kinetic analysis reveals that the introduction of the CuV 2 O 6 phase can enhance the lithium-ion transferring rate and cycling stability of Li 4 Ti 5 O 12 . The enhanced lithium-storage mechanism of the 5 wt % Li 4 Ti 5 O 12 /CuV 2 O 6 composite is clarified by in situ X-ray diffraction (XRD) analysis. The acquired data confirms that in situ formation of small amounts of metallic Cu during discharge/charge processes highly enhance the electronic conductivity and decreases the charge-transfer resistance of Li 4 Ti 5 O 12 . In sum, the as-obtained 5 wt % Li 4 Ti 5 O 12 /CuV 2 O 6 composite has potential for future construction of high-rate and long-lifespan anode materials for Li-ion batteries. The work also provides an innovative route to improve electrochemical performances of Li 4 Ti 5 O 12 .

The on-surface synthesis of single-layered covalent organic frameworks (sCOFs) has been investigated by employing a 3-fold symmetric monomer 1 carrying aldehyde groups and the ditopic diamine building block 2 on a highly oriented pyrolytic graphite surface. The self-assembly of molecule 1 is persistently observed at the stoichiometric ratio of the reactive groups. The growth of sCOF network is observed, however, only at the excess of diamine monomers. By investigating the growth process of the sCOF network, the role of excessive diamine monomers can be understood by two aspects. Increasing the molar ratio of diamine monomer provides the driving force for the structural transition from the monomer self-assembly to the formation of the sCOF network. On the other hand, the excess diamine monomers provide basic environment for the transimination reaction and promote the formation of highly ordered sCOFs. The present work provides molecular understanding of the role of transimination reaction in imine-based COF synthesis.

Although LiV 3 O 8 is regarded as a potential cathode candidate for rechargeable lithium batteries, it has been restricted by its weak dissolution and lattice structure change. Here, polydiphenylamine is successfully introduced to trigger the evolution of LiV 3 O 8 material through an in situ oxidative polymerization method, significantly improving the electrochemical properties and inhibiting the adverse reaction. Expectedly, the 10 wt % LiV 3 O 8 /polydiphenylamine composite delivers a high initial specific discharge capacity of 311 mAh g -1 , which decreases to 272 mAh g -1 after 50 cycles at the current density of 60 mA g -1 . Even at a high current density of 2000 mA g -1 , it still exhibited a reversible specific capacity of 125 mAh g -1 after 50 cycles. Quantitative kinetics analysis confirms the fundamental reasons for the enhanced rate capability. The ex situ X-ray diffraction and scanning electron microscopy results suggest that 10 wt % LiV 3 O 8 /polydiphenylamine composite possesses an ultrahigh structural stability during cycling.

Chiral cage compounds are mainly constructed from chiral precursors or based on the symmetry breaking during coordination-driven self-assembly. Herein, we present a strategy to construct chiral organic cages by restricting the P or M rotational configuration of tetraphenylethylene (TPE) faces through dynamic covalent chemistry. The combination of graph theory, experimental characterizations and theoretical calculations suggests emergent chirality of cages is originated from complex arrangements of TPE faces with different orientational and rotational configurations. Accompanied by the generation of chirality, strong fluorescence also emerged during cage formation, even in dilute solutions with various solvents. In addition, the circularly polarized luminescence of the cages is realized as a synergy of their dual chiral and fluorescence properties. Chirality and fluorescence of cages are remarkably stable, because intramolecular flipping of phenyl rings in TPE faces is restricted, as indicated by calculations. This study provides insight into construct chiral cages by the rational design through graph theory, and might facilitate further design of cages and other supramolecular assemblies from aggregation-induced emission active building blocks.

One-dimensional Sb 2 Se 3 /C rods are prepared through self-assembly by inducing anisotropy, and their corresponding sodium storage behaviors are evaluated, presenting excellent electrochemical performances with superior cycling stability and rate capability. Sb 2 Se 3 delivers a high initial charge capacity of 657.6 mA h g -1 at a current density of 0.2 A g -1 between 2.5 and 0.01 V. After 100 cycles, the reversible capacity of Sb 2 Se 3 /C is still retained at 485.2 mA h g -1 . Even at a high rate current density of 2.0 A g -1 , the charge capacity is still retained at 311.5 mA h g -1 . Through the analysis of cyclic voltammetry and in situ electrochemical impedance spectroscopy, the in-depth understanding of high rate performances is explored effectively. Briefly, the sodium storage performance of Sb 2 Se 3 /C is observably enhanced, benefiting from the 1D structure and the introduction of a carbon layer with robust structure stability and conductivity.

There has been a renewed appreciation for the dynamic nature of ribonucleic acid (RNA) modifications and for the impact of modified RNAs on organism health resulting in an increased emphasis on developing analytical methods capable of detecting modifications within specific RNA sequence contexts. Here we demonstrate that a DNA-based exclusion list enhances data dependent liquid chromatography tandem mass spectrometry (LC-MS/MS) detection of post-transcriptionally modified nucleosides within specific RNA sequences. This approach is possible because all post-transcriptional modifications of RNA, except pseudouridine, result in a mass increase in the canonical nucleoside undergoing chemical modification. Thus, DNA-based sequences reflect the state of the RNA prior to or in the absence of modification. The utility of this exclusion list strategy is demonstrated through the RNA modification mapping of total tRNAs from the bacteria Escherichia coli, Lactococcus lactis, and Streptomyces griseus. Creation of a DNA-based exclusion list is shown to consistently enhance the number of detected modified ribonuclease (RNase) digestion products by ∼20%. All modified RNase digestion products that were detected during standard data dependent acquisition (DDA) LC-MS/MS were also detected when the DNA-based exclusion list was used. Consequently, the increase in detected modified RNase digestion products is attributed to new experimental information only obtained when using the exclusion list. This exclusion list strategy should be broadly applicable to any class of RNA and improves the utility of mass spectrometry approaches for discovery-based analyses of RNA modifications, such as are required for studies of the epitranscriptome.