Nickel‐rich layered lithium transition metal oxides (LiNi1−x−yCoxMnyO2 and LiNi1−x−yCoxAlyO2, x + y ≤ 0.2) are the most attractive cathode materials for the next generation lithium‐ion batteries for ...automotive application. However, they suffer from structural/interfacial instability during repeated charge/discharge, resulting in severe performance degradation and serious safety concerns. This work provides a comprehensive review about challenges and strategies to advance nickel‐rich layered cathodes specifically for harsh (high‐voltage, high‐temperature, and fast charging) operations. Firstly, the degradation pathways of nickel‐rich cathodes including surface/interface degradation, undesired cathode–electrolytes parasitic reactions, gas evolution, inter/intragranular cracking, and electrical/ionic isolation are discussed. Then, recent achievements in stabilizing the structure/interface of nickel‐rich cathodes via surface coating, cation/anion doping, composition tailoring, morphology engineering, and electrolytes optimization are summarized. Moreover, challenges and strategies to improve the performance of Ni‐rich cathodes at the electrode level are discussed. Outlook and perspectives to promote the practical application of nickel‐rich layered cathodes toward automotive application are provided as well.
This review is aimed at a comprehensive discussion on the challenges and strategies (material/electrode structures and interphase) to advance the application of Ni‐rich cathodes for harsh operation (high Ni content, high voltage, high temperature, and high rate).
Scintillation based X-ray detection has received great attention for its application in a wide range of areas from security to healthcare. Here, we report highly efficient X-ray scintillators with ...state-of-the-art performance based on an organic metal halide, ethylenebis-triphenylphosphonium manganese (II) bromide ((C
H
P
)MnBr
), which can be prepared using a facile solution growth method at room temperature to form inch sized single crystals. This zero-dimensional organic metal halide hybrid exhibits green emission peaked at 517 nm with a photoluminescence quantum efficiency of ~ 95%. Its X-ray scintillation properties are characterized with an excellent linear response to X-ray dose rate, a high light yield of ~ 80,000 photon MeV
, and a low detection limit of 72.8 nGy s
. X-ray imaging tests show that scintillators based on (C
H
P
)MnBr
powders provide an excellent visualization tool for X-ray radiography, and high resolution flexible scintillators can be fabricated by blending (C
H
P
)MnBr
powders with polydimethylsiloxane.
Organic metal halide hybrids (OMHHs) have attracted great research attention owing to their exceptional structure and property tunability. Using appropriate organic and inorganic metal halide ...components, OMHHs with controlled dimensionalities at the molecular level, from 3D to 2D, 1D, and 0D structures, can be obtained. In 0D OMHHs, anionic metal halide polyhedrons are surrounded and completely isolated by organic cations to form single crystalline “host–guest” structures. These ionically bonded organic–inorganic hybrid systems often exhibit the intrinsic properties of individual metal halide species, for instance, highly efficient Stokes‐shifted broadband emissions. In this progress report, the recent advances in the development and study of luminescent 0D OMHHs are discussed: from synthetic structural control to fundamental understanding of the structure–property relationship and device integration.
Zero‐dimensional organic metal halide hybrids (0D OMHHs) have emerged as highly promising photoactive hybrid materials with unique properties and applications in a variety of areas. This progress report discusses the recent advances in the development and study of luminescent 0D OMHHs, from synthetic structural control to fundamental understanding of the structure–property relationship and device integration.
Abstract Narrow-line Seyfert 1 galaxies (NLS1s), a subclass of active galactic nuclei (AGNs) in an early stage of the accretion process, are also found to host relativistic jets. However, currently ...known jetted NLS1s are rare. The majority of NLS1s are undetected at the radio band. The radio detection rate of NLS1s increases with the LOFAR Two-metre Sky Survey (LoTSS), which provides a good opportunity for finding more jetted NLS1s. The better sensitivity raises the question whether the radio emission of NLS1s with a low radio luminosity originates from the jet activity. In order to clarify the origin of the radio emission for NLS1s and search for more jetted NLS1s, we explore the mid-infrared properties of LoTSS-detected NLS1s by comparing them with known jetted AGNs and star-forming galaxies (SFGs), which are located above and on the well-studied radio/far-infrared correlation, respectively. The majority of NLS1s show mid-infrared (MIR) excess compared with SFGs. Their radio emission shows a significant correlation with the MIR emission. In the MIR color–color diagram, NLS1s overlap flat spectrum radio quasars, but they are well separated from SFGs and optically selected radio galaxies. The flux ratio of the radio and MIR emission of these NLS1s is also similar to that of a radio-quiet quasar with a weak jet. These results imply substantial contributions from the AGN activities for both the radio and MIR emission of NLS1s. A small fraction of NLS1s with relatively higher radio luminosities are located in a similar region as blazars in the radio-MIR diagram, which suggests that the radio emission of these NLS1s is dominated by the jet. We obtain a sample of jetted NLS1 candidates through their radio excess in the radio-MIR diagram.
Abstract
Graphite, a robust host for reversible lithium storage, enabled the first commercially viable lithium-ion batteries. However, the thermal degradation pathway and the safety hazards of ...lithiated graphite remain elusive. Here, solid-electrolyte interphase (SEI) decomposition, lithium leaching, and gas release of the lithiated graphite anode during heating were examined by in situ synchrotron X-ray techniques and in situ mass spectroscopy. The source of flammable gas such as H
2
was identified and quantitively analyzed. Also, the existence of highly reactive residual lithium on the graphite surface was identified at high temperatures. Our results emphasized the critical role of the SEI in anode thermal stability and uncovered the potential safety hazards of the flammable gases and leached lithium. The anode thermal degradation mechanism revealed in the present work will stimulate more efforts in the rational design of anodes to enable safe energy storage.
Lithium reactivity with electrolytes leads to their continuous consumption and dendrite growth, which constitute major obstacles to harnessing the tremendous energy of lithium-metal anode in a ...reversible manner. Considerable attention has been focused on inhibiting dendrite via interface and electrolyte engineering, while admitting electrolyte-lithium metal reactivity as a thermodynamic inevitability. Here, we report the effective suppression of such reactivity through a nano-porous separator. Calculation assisted by diversified characterizations reveals that the separator partially desolvates Li
in confinement created by its uniform nanopores, and deactivates solvents for electrochemical reduction before Li
-deposition occurs. The consequence of such deactivation is realizing dendrite-free lithium-metal electrode, which even retaining its metallic lustre after long-term cycling in both Li-symmetric cell and high-voltage Li-metal battery with LiNi
Mn
Co
O
as cathode. The discovery that a nano-structured separator alters both bulk and interfacial behaviors of electrolytes points us toward a new direction to harness lithium-metal as the most promising anode.
DNA demethylation can occur passively by “dilution” of methylation marks by DNA replication, or actively and independently of DNA replication. Direct conversion of 5‐methylcytosine (5mC) to cytosine ...(C), as originally proposed, does not occur. Instead, active DNA methylation involves oxidation of the methylated base by ten‐eleven translocations (TETs), or deamination of the methylated or a nearby base by activation induced deaminase (AID). The modified nucleotide, possibly together with surrounding nucleotides, is then replaced by the BER pathway. Recent data clarify the roles and the regulation of well‐known enzymes in this process. They identify base excision repair (BER) glycosylases that may cooperate with or replace thymine DNA glycosylase (TDG) in the base excision step, and suggest possible involvement of DNA damage repair pathways other than BER in active DNA demethylation. Here, we review these new developments.
DNA methylation is not forever. It can be lost passively during DNA replication or removed actively. Active erase of methylation begins with modification of the methylated or a nearby nucleotide by AID‐mediated deamination or TET‐mediated oxidation, and ends with replacement of the modified nucleotide by DNA damage repair pathways.
Zero‐dimensional (0D) organic metal halide hybrids, in which organic and metal halide ions cocrystallize to form neutral species, are a promising platform for the development of multifunctional ...crystalline materials. Herein we report the design, synthesis, and characterization of a ternary 0D organic metal halide hybrid, (HMTA)4PbMn0.69Sn0.31Br8, in which the organic cation N‐benzylhexamethylenetetrammonium (HMTA+, C13H19N4+) cocrystallizes with PbBr42−, MnBr42−, and SnBr42−. The wide band gap of the organic cation and distinct optical characteristics of the three metal bromide anions enabled the single‐crystalline “host–guest” system to exhibit emissions from multiple “guest” metal halide species simultaneously. The combination of these emissions led to near‐perfect white emission with a photoluminescence quantum efficiency of around 73 %. Owing to distinct excitations of the three metal halide species, warm‐ to cool‐white emissions could be generated by controlling the excitation wavelength.
The right white light: The ternary organic metal halide hybrid (HMTA)4PbMn0.69Sn0.31Br8 contains three distinct metal halide species comprising emissions to cover the blue, green, and red spectral regions (the different colors in the picture represent unit cells of single‐component metal halide crystals with HMTA+). The multicomponent single‐crystalline material exhibited warm‐white to cool‐white emissions at appropriate excitation wavelengths.
Phthalates are a group of diesters of ortho‐phthalic acid (dialkyl or alkyl aryl esters of 1,2‐benzenedicarboxylic acid). Higher‐molecular‐weight phthalates, such as di‐2‐ethylhexyl phthalate (DEHP), ...are primarily used as plasticizers to soften polyvinyl chloride (PVC) products, while the lower‐molecular‐weight phthalates, such as diethyl phthalate (DEP), di‐n‐butyl phthalate (DBP), and butyl benzyl phthalate (BBzP), are widely used as solvents to hold color and scent in various consumer and personal care products. Phthalates have become ubiquitous environmental contaminants due to volatilization and leaching from their widespread applications, and thus contamination of the environment has become another important source for phthalates in foods in addition to migration from packaging materials. Human exposure to phthalates has been an increased concern due to the findings from toxicology studies in animals. DEHP, one of the important and widely used phthalates, is a rodent liver carcinogen. DEHP, DBP, BBzP, and several phthalate metabolites, such as monobutyl phthalate, monobenzyl phthalate, and mono‐(2‐ethylhexyl) phthalate, are teratogenic in animals. Since foods are the major source of exposure to phthalates, information on levels of phthalates in foods is important for human exposure assessment. The objective of this review is to identify the knowledge gaps for future investigations by reviewing levels of a wide range of phthalates in a variety of foods, such as bottled water, soft drinks, infant formula, human milk, total diet foods, and others, migration of phthalates from various food‐packaging materials, and traditional and new methodologies for the determination of phthalates in foods.
Considering the natural abundance and low cost of sodium resources, sodium‐ion batteries (SIBs) have received much attention for large‐scale electrochemical energy storage. However, smart structure ...design strategies and good mechanistic understanding are required to enable advanced SIBs with high energy density. In recent years, the exploration of advanced cathode, anode, and electrolyte materials, as well as advanced diagnostics have been extensively carried out. This review mainly focuses on the challenging problems for the attractive battery materials (i.e., cathode, anode, and electrolytes) and summarizes the latest strategies to improve their electrochemical performance as well as presenting recent progress in operando diagnostics to disclose the physics behind the electrochemical performance and to provide guidance and approaches to design and synthesize advanced battery materials. Outlook and perspectives on the future research to build better SIBs are also provided.
Room temperature sodium‐ion batteries show great promise for large scale electrochemical energy storage application because of the low cost and large abundance of sodium resource. The progress and main challenges regarding the development of electrode, electrolytes, and advanced diagnostics are summarized with the aim of achieving a high energy density of over 400 Wh kg−1 on the cell level.
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