Enhancing the Anode Performance of Antimony through Nitrogen-Doped Carbon and Carbon Nanotubes

Antimony is a promising high-capacity anode material in sodium-ion batteries, but it generally shows poor cycling stability because of its large volume changes during sodium ion insertion and extraction processes. To alleviate or even overcome this problem, we develop a hybrid carbon encapsulation strategy to improve the anode performance of antimony through the combination of antimony/nitrogen-doped carbon (Sb/N-carbon) hybrid nanostructures and the carbon nanotube (CNT) network. When evaluated as an anode material for sodium-ion batteries, the as-synthesized Sb/N-carbon + CNT composite exhibits superior cycling stability and rate performance in comparison with Sb/N-carbon or Sb/CNT composite. A high charge capacity of 543 mA h g^–1 with initial charge capacity retention of 87.7% is achieved after 200 cycles at a current density of 0.1 A g^–1. Even under 10 A g^–1, a reversible capacity of 258 mA h g^–1 can be retained. The excellent sodium storage properties can be attributed to the formation of Sb–N bonding between the antimony nanoparticle and the nitrogen-doped carbon shell in addition to the electronically conductive and flexible CNT network. The hybrid carbon encapsulation strategy is simple yet very effective, and it also provides new avenues for designing advanced anode materials for sodium-ion batteries

Strongly Bonded Selenium/Microporous Carbon Nanofibers Composite as a High-Performance Cathode for Lithium–Selenium Batteries

Although lithium–selenium batteries have attracted significant attention for high-energy-density energy storage systems due to their high volumetric capacity, their implementation has been hampered by the dissolution of polyselenide intermediates into electrolyte. Herein, we report a novel selenium/microporous carbon nanofiber composite as a high-performance cathode for lithium–selenium batteries through binding selenium in microporous carbon nanofibers. Under vacuum and heat treatment, selenium particles are easily transformed into chainlike Se_<i>n</i> molecules that chemically bond with the inner surfaces of microporous carbon nanofibers. This chemical bonding can not only promote robust and intimate contact between selenium and carbonaceous nanofiber matrix but also alleviate the active material dissolution during cycling. Moreover, selenium is homogeneously distributed in the micropores of the highly conductive carbonaceous nanofiber matrix, which is favorable for the fast diffusions of both lithium ions and electrons. As a result, a high reversible capacity of 581 mA h g^–1 in the first cycle at 0.1 C and over 400 mA h g^–1 after 2000 cycles at 1 C with excellent cyclability and high rate performance (over 420 mA h g^–1 at 5 C, 3.39 A g^–1) are achieved with the selenium/microporous carbon nanofibers composite as a cathode for lithium–selenium batteries, performing among the best of current selenium–carbon cathodes. This simple preparation method and strongly coupling hybrid nanostructure can be extended to other selenium-based alloy cathode materials for lithium–selenium batteries

A Chemically Coupled Antimony/Multilayer Graphene Hybrid as a High-Performance Anode for Sodium-Ion Batteries

Sodium-ion batteries have recently attracted considerable attention as a promising alternative to lithium-ion batteries owing to the natural abundance and low cost of sodium compared with lithium. Among all proposed anode materials for sodium-ion batteries, antimony is a desirable candidate due to its high theoretical capacity (660 mA h g^–1). Herein, an antimony/multilayer graphene hybrid, in which antimony is homogeneously anchored on multilayer graphene, is produced by a confined vapor deposition method. The chemical bonding can realize robust and intimate contact between antimony and multilayer graphene, and the uniform distribution of antimony and the highly conductive and flexible multilayer graphene can not only improve sodium ion diffusion and electronic transport but also stabilize the solid electrolyte interphase upon the large volume changes of antimony during cycling. Consequently, the antimony/multilayer graphene hybrid shows a high reversible sodium storage capacity (452 mA h g^–1 at a current density of 100 mA g^–1), stable long-term cycling performance with 90% capacity retention after 200 cycles, and excellent rate capability (210 mA h g^–1 under 5000 mA g^–1). This facile synthesis approach and unique nanostructure can potentially be extended to other alloy materials for sodium-ion batteries

Improving the Anode Performance of WS₂ through a Self-Assembled Double Carbon Coating

Tungsten disulfide, which possesses a well-defined layered structure, has been intensively studied as an anode material for lithium ion batteries, but it usually suffers from poor cycling stability because of its large volume changes during lithium insertion and extraction processes. Herein, we develop a self-assembled double carbon coating to enhance the anode performance of WS₂ via a self-assembly process between oleylamine-coated WS₂ nanosheets and graphene oxide and subsequent pyrolysis treatment. When employed as an anode material for lithium ion batteries, the as-prepared WS₂@C/reduced graphene oxide (WS₂@C/RGO) composite exhibits excellent cycling stability and rate capability when compared to WS₂@C nanosheets. A reversible capacity of 486 mA h g^–1 and around 90% capacity retention were obtained after 200 cycles at a current density of 0.5 A g^–1. Even under 10 A g^–1, a high reversible capacity of 126 mA h g^–1 can be retained. The good electrochemical performance could be attributed to the external electronically conductive and flexible RGO coating in addition to the surface carbon layer and the uniform distribution of WS₂ nanosheets. The self-assembled dual carbon coating strategy is facile yet effective, and it may be applied to other high-capacity anode materials with huge volume changes and poor electrical conductivities

Fluorine-Doped Carbon Particles Derived from Lotus Petioles as High-Performance Anode Materials for Sodium-Ion Batteries

In contrast to the extensive investigation of the electrochemical performance of conventional carbon materials in sodium-ion batteries, there has been scarcely any study of sodium storage property of fluorine-doped carbon. Here we report for the first time the application of fluorine-doped carbon particles (F-CP) synthesized through pyrolysis of lotus petioles as anode materials for sodium-ion batteries. Electrochemical tests demonstrate that the F-CP electrode delivers an initial charge capacity of 230 mA h g^–1 at a current density of 50 mA g^–1 between 0.001 and 2.8 V, which greatly outperforms the corresponding value of 149 mA h g^–1 for the counterpart banana peels-derived carbon (BPC). Even under 200 mA g^–1, the F-CP electrode could still exhibit a charge capacity of 228 mA h g^–1 with initial charge capacity retention of 99.1% after 200 cycles compared to the BPC electrode with 107 mA h g^–1 and 71.8%. The F-doping and the large interlayer distance as well as the disorder structure contribute to a lowering of the sodium ion insertion–extraction barrier, thus promoting the Na⁺ diffusion and providing more active sites for Na⁺ storage. In specific, the F-CP electrode shows longer low-discharge-plateau and better kinetics than does the common carbon-based electrode. The unique electrochemical performance of F-CP enriches the existing knowledge of the carbon-based electrode materials and broadens avenues for rational design of anode materials in sodium-ion batteries

Understanding the Effect of Different Polymeric Surfactants on Enhancing the Silicon/Reduced Graphene Oxide Anode Performance

Silicon-based lithium-ion battery anodes have brought encouraging results to the current state-of-the-art battery technologies due to their high theoretical capacity, but their large-scale application has been hampered by a large volume change (>300%) of silicon upon lithium insertion and extraction, which leads to severe electrode pulverization and capacity degradation. Polymeric surfactants directing the combination of silicon nanoparticles and reduced graphene oxide have attracted great interest as promising choices for accommodating the huge volume variation of silicon. However, the influence of different polymeric surfactants on improving the electrochemical performance of silicon/reduced graphene oxide (Si/RGO) anodes remains unclear because of the different structural configurations of polymeric surfactants. Here, we systematically study the effect of different polymeric surfactants on enhancing the Si/RGO anode performance. Three of the most well-known polymeric surfactants, poly­(sodium 4-styrenesulfonate) (PSS), poly­(diallydimethylammonium chloride) (PDDA), and polyvinylpyrrolidone (PVP), were used to direct the combination of silicon nanoparticles and RGO through van der Waals interaction. The Si/RGO anodes made from these composites act as ideal models to investigate and compare how the van der Waals forces between polymeric surfactants and GO affect the final silicon anode performance from both experimental observations and theoretical simulations. We found that the capability of these three surfactants in enhancing long-term cycling stability and high-rate performance of the Si/RGO anodes decreased in the order of PVP > PDDA > PSS

Table1_Prenatal diagnosis of micrognathia: a systematic review.pdf

PurposeThis systematic review aimed to analyze the characteristics of different diagnostic techniques for micrognathia, summarize the consistent diagnostic criteria of each technique, and provide a simple and convenient prenatal diagnosis strategy for micrognathia.MethodsIn accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the search was undertaken in three international databases (PubMed, Scopus, and Web of Science). The three reviewers assessed all papers and extracted the following variables: author's name and year of publication, country, study design, number of participants, gestational age, equipment for prenatal examination, biometric parameters related to micrognathia, main results.ResultsA total of 25 articles included in the analysis. Nineteen articles described cross-sectional studies (76 percent), 4 (16 percent) were case-control studies, and 2 (8 percent) were cohort studies. Fifteen studies (60 percent) had a prospective design, 9 (36 percent) had a retrospective design, and one (4 percent) had both prospective and retrospective design. Thirty-two percent of the studies (n = 8) were performed in USA, and the remaining studies were performed in China (n = 4), Israel (n = 3), Netherlands (n = 3), UK (n = 1), France (n = 1), Italy (n = 1), Belgium(n = 1), Germany (n = 1), Spain (n = 1), and Austria (n = 1). The prenatal diagnosis of micrognathia can be performed as early as possible in the first trimester, while the second and third trimester of pregnancy were the main prenatal diagnosis period. The articles that were included in the qualitative synthesis describe 30 biometric parameters related to the mandible.ConclusionOf the 30 biometric parameters related to the mandible, 15 can obtain the simple and convenient diagnostic criteria or warning value for micrognathia. Based on these diagnostic criteria or warning value, clinicians can quickly make a preliminary judgment on facial deformities, to carry out cytologic examination to further clarify the diagnosis of micrognathia.</p

Spatiotemporal variation of cyanobacterial harmful algal blooms in China based on literature and media information

Cyanobacterial harmful algal blooms (CyanoHABs) in inland waters are now among the most pressing environmental issues worldwide, especially in China. Satellite remote sensing has limitations in monitoring CyanoHABs in small water bodies due to spatial and temporal resolution limitations. While literature and news media have the potential to supplement satellite remote sensing in monitoring CyanoHABs, they have currently not received sufficient attention. In this study, we combined information on the distributions of CyanoHABs from literature and media for the first time to comprehensively assess the spatiotemporal variation in CyanoHABs in China. We collected, cleaned, validated, and organized data from literature and media on CyanoHABs in China, resulting in the establishment of a comprehensive database on CyanoHABs in China's inland waters (ChinaCyanoDB) covering 198 water bodies, 525 records for 1950–2021. The majority of water bodies with CyanoHABs (CyanoWaters) are located in the eastern China, mainly concentrated in the middle and lower Yangtze region, with a clear upward trend in their number over the last four decades. The ChinaCyanoDB and analytical results can provide valuable data support for monitoring and managing CyanoHABs in China while the database construction method may also be applied to other countries and regions.</p