To pursue a higher energy density (>300 Wh kg−1 at the cell level) and a lower cost (<$125 kWh−1 expected at 2022) of Li‐ion batteries for making electric vehicles (EVs) long range and ...cost‐competitive with internal combustion engine vehicles, developing Ni‐rich/Co‐poor layered cathode (LiNi1−x−yCoxMnyO2, x+y ≤ 0.2) is currently one of the most promising strategies because high Ni content is beneficial to high capacity (>200 mAh g−1) while low Co content is favorable to minimize battery cost. Unfortunately, Ni‐rich cathodes suffer from limited structure stability and electrode/electrolyte interface stability in the charged state, leading to electrode degradation and poor cycling performance. To address these problems, various strategies have been employed such as doping, structural optimization design (e.g., core–shell structure, concentration‐gradient structure, etc.), and surface coating. In this review, five key aspects of Ni‐rich/Co‐poor layered cathode materials are explored: energy density, fast charge capability, service life including cycling life and calendar life, cost and element resources, and safety. This enables a comprehensive analysis of current research advances and challenges from the perspective of both academy and industry to help facilitate practical applications for EVs in the future.
Current research advances and challenges in the field of Ni‐rich NCM cathodes for electric vehicles both in academy and industry, along with future perspectives are discussed. Ni‐rich NCM cathodes for automotive applications in five key aspects including energy density, fast charge capability, service life, cost and element resources, and safety are analyzed comprehensively.
Energy bands in antiferromagnets are supposed to be spin degenerate in the absence of spin–orbit coupling (SOC). Recent studies have identified formal symmetry conditions for antiferromagnetic ...crystals in which this degeneracy can be lifted, spin splitting,even in the vanishing SOC (i.e., non‐relativistic) limit. Materials having such symmetries could enable spin‐split antiferromagnetic spintronics without the burden of using heavy‐atom compounds. However, the symmetry conditions that involve spin and magnetic symmetry are not always effective as practical material selection filters. Furthermore, these symmetry conditions do not readily disclose trends in the magnitude and momentum dependence of the spin‐splitting energy. Here, it is shown that the formal symmetry conditions enabling spin‐split antiferromagnets can be interpreted in terms of local motif pairs, such as octahedra or tetrahedra, each carrying opposite magnetic moments. Collinear antiferromagnets with such a spin‐structure motif pair, whose components interconvert by neither translation nor spatial inversion, will show spin splitting. Such a real‐space motif‐based approach enables an easy way to identify and design materials (illustrated in real example materials) having spin splitting without the need for SOC, and offers insights into the momentum dependence and magnitude of the spin splitting.
Energy bands in antiferromagnets with compensated magnetization are expected to maintain spin degeneracy without spin–orbit coupling (SOC). In this work, collinear antiferromagnets with a spin‐structure motif pair are shown,whose components cannot be interconverted by certain spatial transformation; these will show spin splitting. Such a motif‐based rule allows easy discerning of spin‐split antiferromagnets from conventional spin‐degenerate antiferromagnets.
Constructing 3D carbon structures built from carbon nanotubes (CNTs) and graphene has been considered as an effective approach to achieve superior properties in energy conversion and storage because ...of the synergistic combination of the advantages of each building block. Herein, a facile solid‐state growth strategy is reported for the first time to fabricate highly nitrogen doped CNT–graphene 3D nanostructures without the necessity to use chemical vapor deposition. As cathode hosts for lithium–sulfur batteries, the hybrid architectures exhibit reversible capacities of 1314 and 922 mAh g−1 at 0.2 and 1 C, respectively, and a capacity retention of 97% after 200 cycles at a high rate of 2 C, revealing their great potential for energy storage application.
Using a facile and green solid‐state growth strategy, 3D, well‐interconnected, highly nitrogen‐doped carbon nanotube–graphene hybrid structures are designed and fabricated by using Ni foam as growth substrate and catalyst, glucose as carbon sources, and dicyandiamide as nitrogen sources. When used as cathode hosts for Li–S batteries, the obtained product shows superior lithium‐storage capability.
Alzheimer's disease (AD) is the most common type of dementia, and no disease-modifying treatments are available to halt or slow its progression. Amyloid-beta (Aβ) is suggested to play a pivotal role ...in the pathogenesis of AD, and clearance of Aβ from the brain becomes a main therapeutic strategy for AD. Recent studies found that Aβ clearance in the periphery contributes substantially to reducing Aβ accumulation in the brain. Therefore, understanding the mechanism of how Aβ is cleared in the periphery is important for the development of effective therapies for AD. In this review, we summarized recent findings on the mechanisms of Aβ efflux from the brain to the periphery and discuss where and how the brain-derived Aβ is cleared in the periphery. Based on these findings, we propose future strategies to enhance peripheral Aβ clearance for the prevention and treatment of AD. This review provides a novel perspective to understand the pathogenesis of AD and develop interventions for this disease from a systemic approach.
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs (typically consisting of 18–25 nucleotides) that negatively control expression of target genes at the post-transcriptional level. Owing to the ...biological significance of miRNAs, miRTarBase was developed to provide comprehensive information on experimentally validated miRNA–target interactions (MTIs). To date, the database has accumulated >13,404 validated MTIs from 11,021 articles from manual curations. In this update, a text-mining system was incorporated to enhance the recognition of MTI-related articles by adopting a scoring system. In addition, a variety of biological databases were integrated to provide information on the regulatory network of miRNAs and its expression in blood. Not only targets of miRNAs but also regulators of miRNAs are provided to users for investigating the up- and downstream regulations of miRNAs. Moreover, the number of MTIs with high-throughput experimental evidence increased remarkably (validated by CLIP-seq technology). In conclusion, these improvements promote the miRTarBase as one of the most comprehensively annotated and experimentally validated miRNA–target interaction databases. The updated version of miRTarBase is now available at http://miRTarBase.cuhk.edu.cn/.
Electronic structure engineering on electrode materials could bring in a new mechanism to achieve high energy and high power densities in sodium ion batteries. Herein, we design and create Co ...vacancies at the interface of atomically thin CoSe2/graphene heterostructure and obtain Co1−xSe2/graphene heterostructure electrode materials that facilitate significant Na+ intercalation pseudocapacitance. Density functional theory (DFT) calculation suggests that the Na+ adsorption energy is dramatically increased, and the Na+ diffusion barrier is remarkably reduced due to the introduction of Co vacancy. The optimized electrode delivers a superior capacity of 673.6 mAh g−1 at 0.1 C, excellent rate capability of 576.5 mAh g−1 at 2.0 C and ultra‐long life up to 2000 cycles. Kinetics analysis indicates that the enhanced Na+ storage is mainly attributed to the intercalation pseudocapacitance induced by Co vacancies. This work suggests that the creation of cation vacancy could bestow heterostructured electrode materials with pseudocapacitive Na+ intercalation for high‐capacity and high‐rate energy storage.
The Co vacancies (VCo) at the interface of Co1−xSe2/graphene (GE) afford strong adsorption of Na+ and a low Na+ diffusion energy barrier to facilitate rapid intercalation/deintercalation of Na+ ions giving remarkable pseudocapacitance. The as‐prepared Co1−xSe2/GE‐based sodium ion batteries deliver high specific/rate capacity performance and exceptional cycling performance.
A lamellar hybrid assembled from metal disulfide (MoS2, WS2) nanowall arrays anchored on nitrogen‐doped carbon layers is developed via an in situ hybridization strategy through a synergistic ...pyrolysis reaction of thiourea and oxometalates. Such a hybrid provides adequate electrical and chemical coupling between the active materials and the carbon substrate, thus realizing a high‐efficiency electron‐conduction/ion‐transportation system and exhibiting excellent sodium‐storage properties.
Efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes highly rely on the rational design and synthesis of high‐performance electrocatalysts. Herein, comprehensive ...characterizations and density functional theory (DFT) calculations are combined to verify the important roles of the crystallinity and oxygen vacancy levels of Co(II) oxide (CoO) on ORR and OER activities. A facile and controllable vacuum‐calcination strategy is utilized to convert Co(OH)2 into oxygen‐defective amorphous‐crystalline CoO (namely ODAC‐CoO) nanosheets. With the carefully controlled crystallinity and oxygen vacancy levels, the optimal ODAC‐CoO sample exhibits dramatically enhanced ORR and OER electrocatalytic activities compared with the pure crystalline CoO counterpart. The assembled liquid and quasi‐solid‐state Zn–air batteries with ODAC‐CoO as cathode material achieve remarkable specific capacity, power density, and excellent cycling stability, outperforming the benchmark Pt/C+IrO2 catalysts. This study theoretically proposes and experimentally demonstrates that the simultaneous introduction of amorphous structures and oxygen vacancies could be an effective avenue towards high‐performance electrocatalytic ORR and OER.
A facile and controllable vacuum‐calcination strategy is implemented to engineer the crystallinity and oxygen vacancies of ultrathin CoO nanosheets for rechargeable Zn–air batteries. The resultant samples exhibit a unique amorphous‐crystalline feature and tunable oxygen vacancy level. Enhanced electrocatalytic performance is achieved on such oxygen‐defective amorphous‐crystalline CoO nanosheets compared with the corresponding crystalline counterpart.
Methodology development of robust linkages is fundamentally important for the synthesis and application of covalent organic frameworks (COFs). We report herein a new strategy based on multicomponent ...reactions (MCRs) to construct ultrastable COFs. With the one-pot formation of five covalent bonds in each cyclic joint, a series of imidazole-linked COFs were robustly constructed through the Debus–Radziszewski MCR from three easily available components. By reaching a higher level of complexity and precision in covalent assembly, this research explores a new direction in integrating sophisticated reversible/irreversible reactions to construct crystalline porous frameworks.
Heteroatom doping plays a significant role in optimizing the catalytic performance of electrocatalysts. However, research on heteroatom doped electrocatalysts with abundant defects and well‐defined ...morphology remain a great challenge. Herein, a class of defect‐engineered nitrogen‐doped Co3O4 nanoparticles/nitrogen‐doped carbon framework (N‐Co3O4@NC) strongly coupled porous nanocubes, made using a zeolitic imidazolate framework‐67 via a controllable N‐doping strategy, is demonstrated for achieving remarkable oxygen evolution reaction (OER) catalysis. X‐ray photoelectron spectroscopy, X‐ray absorption fine structure, and electron spin resonance results clearly reveal the formation of a considerable amount of nitrogen dopants and oxygen vacancies in N‐Co3O4@NC. The defect engineering of N‐Co3O4@NC makes it exhibit an overpotential of only 266 mV to reach 10 mA cm−2, a low Tafel slope of 54.9 mV dec−1 and superior catalytic stability for OER, which is comparable to that of commercial RuO2. Density functional theory calculations indicate N‐doping could promote catalytic activity via improving electronic conductivity, accelerating reaction kinetics, and optimizing the adsorption energy for intermediates of OER. Interestingly, N‐Co3O4@NC also shows a superior oxygen reduction reaction activity, making it a bifunctional electrocatalyst for zinc–air batteries. The zinc–air battery with the N‐Co3O4@NC cathode demonstrates superior efficiency and durability, showing the feasibility of N‐Co3O4/NC in electrochemical energy devices.
Defect‐rich nitrogen doped Co3O4 nanoparticles/nitrogen‐doped carbon framework strongly coupled porous nanocubes (N‐Co3O4@NC) are prepared via a simple metal–organic framework‐induced and controllable nitrogen‐doping strategy. Profiting from the considerable amount of nitrogen dopants and oxygen vacancy defects, N‐Co3O4@NC behaves as an excellent bifunctional oxygen electrocatalyst, and shows superior efficiency and durability for the as‐assembled zinc–air battery.
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