Hard carbons represent the anode of choice for sodium-ion batteries. Their structure, sodium storage mechanism and sustainability are reviewed, highlighting the challenges for the rational design of ...optimized anode materials through the deep understanding of the structure–function correlations.
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Hard carbons are extensively studied for application as anode materials in sodium-ion batteries, but only recently a great interest has been focused toward the understanding of the sodium storage mechanism and the comprehension of the structure–function correlation. Although several interesting mechanisms have been proposed, a general mechanism explaining the observed electrochemical processes is still missing, which is essentially originating from the remaining uncertainty on the complex hard carbons structure. The achievement of an in-depth understanding of the processes occurring upon sodiation, however, is of great importance for a rational design of optimized anode materials.
In this review, we aim at providing a comprehensive overview of the up-to-date known structural models of hard carbons and their correlation with the proposed models for the sodium-ion storage mechanisms. In this regard, a particular focus is set on the most powerful analytical tools to study the structure of hard carbons (upon de-/sodiation) and a critical discussion on how to interpret and perform such analysis. Targeting the eventual commercialization of hard carbon anodes for sodium-ion batteries – after having established a fundamental understanding – we close this review with a careful evaluation of potential strategies to ensure a high degree of sustainability, since this is undoubtedly a crucial parameter to take into account for the future large-scale production of hard carbons.
Sodium-ion batteries (SIBs) are considered to be a promising low-cost alternative to common lithium-ion batteries. Herein, we present a detailed electrochemical characterization of anatase TiO2 ...nanoparticles as anode material for Na-ion batteries, highlighting the substantial influence of the electrolyte composition (salt and solvent) on the obtainable specific capacity, cycling stability, and particularly the coulombic efficiency. TiO2-based electrodes cycled using a 1M solution of NaClO4 in a mixture of ethylene carbonate and propylene carbonate present excellent high rate capability, offering about 100 and 86 mAh g−1 at 5.5 and 11C, respectively, which is – to the best of our knowledge – the best high rate capability for all titanium-based sodium-ion anode materials reported so far. Setting the C rate to 5.5C (i.e., 1.85 A g−1), such electrodes can be cycled for more than 1000 cycles without significant capacity decay, confirming their outstanding durability at such high specific current. These results, in combination with its environmental friendliness and cost efficiency, render anatase TiO2 nanoparticles a promising anode material for high power sodium-ion batteries.
•Anatase TiO2 nanoparticles reveal reversible Na-ion uptake and release.•Effect of electrolyte composition on cyclability of anatase TiO2 Na-ion anodes.•Anatase TiO2 electrodes show superior high rate capability.•Anatase TiO2 electrodes offer extremely long cycle life at elevated C rates.
High surface area, nanostructured, and phase-pure TiO2(B) noodles-like secondary particles were successfully synthesized by a facile one-pot synthesis, based on the hydrolysis of TiCl3 using a ...mixture of ethylene glycol and water at moderate temperature. The primary nanoparticles have a uniform size and are about 15 nm in diameter as determined by TEM analysis and exhibit an increased exposure of the (010) facet as indicated by XRD analysis. Unlike the electrochemical reaction with lithium, the application as sodium-ion electrode material reveals substantial differences, including the initial amorphization of the TiO2(B) particles, accompanied by a partial irreversibility of the sodium storage, presumably related to sodium trapping inside the active material particles and the absence of a stable solid electrolyte interphase, as indicated by galvanostatic cycling and electrochemical impedance spectroscopy, respectively. Besides, TiO2(B)-based electrodes show a stabilized reversible capacity of about 100 mAh g−1 and a very good C rate capability.
FZB42, the model strain for Gram-positive plant-growth-promoting and biocontrol rhizobacteria, has been isolated in 1998 and sequenced in 2007. In order to celebrate these anniversaries, we summarize ...here the recent knowledge about FZB42. In last 20 years, more than 140 articles devoted to FZB42 have been published. At first, research was mainly focused on antimicrobial compounds, apparently responsible for biocontrol effects against plant pathogens, recent research is increasingly directed to expression of genes involved in bacteria-plant interaction, regulatory small RNAs (sRNAs), and on modification of enzymes involved in synthesis of antimicrobial compounds by processes such as acetylation and malonylation. Till now, 13 gene clusters involved in non-ribosomal and ribosomal synthesis of secondary metabolites with putative antimicrobial action have been identified within the genome of FZB42. These gene clusters cover around 10% of the whole genome. Antimicrobial compounds suppress not only growth of plant pathogenic bacteria and fungi, but could also stimulate induced systemic resistance (ISR) in plants. It has been found that besides secondary metabolites also volatile organic compounds are involved in the biocontrol effect exerted by FZB42 under biotic (plant pathogens) and abiotic stress conditions. In order to facilitate easy access to the genomic data, we have established an integrating data bank 'AmyloWiki' containing accumulated information about the genes present in FZB42, available mutant strains, and other aspects of FZB42 research, which is structured similar as the famous SubtiWiki data bank.
In this paper, we show that the empirical measure of mean-field model satisfies the large deviation principle with respect to the weak convergence topology or the stronger Wasserstein metric, under ...the strong exponential integrability condition on the negative part of the interaction potentials. In contrast to the known results we prove this without any continuity or boundedness condition on the interaction potentials. The proof relies mainly on the law of large numbers and the exponential decoupling inequality of de la Peña for U-statistics.
It is frequently assumed that sodium‐ion battery chemistry exhibits a behavior that is similar to the more frequently investigated lithium‐ion chemistry. However, in this work it is shown that there ...are great, and rather surprising, differences, at least in the case of anatase TiO2. While the generally more reducing lithium ion is reversibly inserted in the anatase TiO2 lattice, sodium ions appear to partially reduce the rather stable oxide and form metallic titanium, sodium oxide, and amorphous sodium titanate, as revealed by means of in situ X‐ray diffraction, ex situ X‐ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. Nevertheless, once the electrochemical transformation of anatase TiO2 is completed, the newly formed material presents a very stable long‐term cycling performance, excellent high rate capability, and superior coulombic efficiency, highlighting it as a very promising anode material for sodium‐ion battery applications.
The electrochemical reaction of sodium and nanoparticulate anatase TiO2 is investigated, revealing that sodium ions partially reduce the rather stable oxide and form metallic titanium, sodium oxide, and amorphous sodium titanate. Once this electrochemical transformation of anatase TiO2 is complete, the newly formed material presents very stable long‐term cycling performance and excellent high rate capability.
To evaluate the efficacy and safety of different antiplatelet therapies for stable angina patients with complicated left main coronary artery lesions and intermediate metabolizer Cytochrome P450 2C19 ...gene (CYP2C19) undergoing PCI.
A total of 247 patients diagnosed with stable angina in cardiology department of Fujian union hospital from February 2015 to February 2017 were retrospectively analyzed, among them, the elective PCI were performed on the left main coronary artery and the CYP2C19 gene poly-morphism were intermediate metabolize, they were divided into ticagrelor treatment group(aspirin combined with ticagrelor,
=95)and clopidogrel treatment group(aspirin combined with clopidogrel,
=152) according to the different antiplatelet treatment programs. Both groups were given aspirin 300 mg and clopidogrel 300 mg orally before PCI; the ticagrelor group were given the maintenance dose of ticagrelor (90 mg orally, twice a day) after PCI, while those in clopidogrel group were clopidogrel 75 mg orally (once a day
Scope
Dietary supplementation with polyphenol‐rich propolis can protect against experimentally induced colitis. We examined whether different polyphenol compositions of Chinese propolis (CP) and ...Brazilian propolis (BP) influence their ability to protect against dextran sulfate sodium (DSS)‐induced colitis in rats.
Methods and results
HPLC‐DAD/Q‐TOF‐MS analysis confirmed that polyphenol compositions of CP and BP were dissimilar. Rats were given CP or BP by gavage (300 mg kg−1 body weight) throughout the study, starting 1 week prior to DSS treatment for 1 week followed by 3 d without DSS. CP and BP significantly reduced the colitis disease activity index relative to controls not receiving propolis, prevented significant DSS‐induced colonic tissue damage, and increased resistance to DSS‐induced colonic oxidative stress as shown by reduced malonaldehyde levels and increased T‐AOC levels. CP and BP significantly reduced DSS‐induced colonic apoptosis. Colonic inflammatory markers IL‐1β, IL‐6, and MCP‐1 were suppressed by CP and BP, whereas only BP‐induced expression of TGF‐β. CP, not BP, increased the diversity and richness of gut microbiota populations. Both forms of propolis significantly reduced populations of Bacteroides spp.
Conclusions
Despite the dissimilar polyphenol compositions of CP and BP, their ability to protect against DSS‐induced colitis is similar. Nevertheless, some different physiological impacts were observed.
Propolis is an important hive product with abundant polyphenols. Here, it is shown that despite the dissimilar polyphenol compositions of Chinese and Brazilian propolis, their abilities to protect against dextran sulfate sodium–induced colitis are similar. It is also demonstrated that reduced populations of Bacteroides spp. by propolis are important for maintaining gut hemostasis.
Considering anti-rotation of sand particles, two-dimensional Discrete Element Method (DEM) has been employed to reproduce direct shear behaviors of sand with different particle distribution sizes, so ...as to explore effects of anti-rotation of particle on responses of stress-displacement and dilatancy, the evolution law of shear stress, coordination number and vertical displacement of sand samples, and analyze the contact force chain, contact fabric and porosity of the samples after shearing.The results show that the anti-rotation ability of sand is enhanced, the torque of overcoming the relative rotation between particles is increased, and the peak shear stress, dilatancy and porosity in the middle of the sample are increased; with the increase of the anti-rotation coefficient, the coordination number decreases more obviously. The proportion of the contact number in the direction of 100°-160° to the total contact number decreases with the increase of the anti-rotation coefficient. The elliptical shape of the contact configuration becomes more flat, and the anisotropy of the contact force chain is more obvious; compared with fine sand, the coarse sand has greater shear capacity, more obvious dilatancy and larger porosity in the middle of the sample.The maximum minimum particle size ratio of the sample becomes larger, so that the shear strength of the sample is reduced, and the dilatancy is also weak.
Bacterial volatiles play a significant role in promoting plant growth by regulating the synthesis or metabolism of phytohormones.
and growth chamber experiments were conducted to investigate the ...effect of volatile organic compounds (VOCs) produced by the plant growth promoting rhizobacterium
strain SYST2 on hormone regulation and growth promotion in tomato plants. We observed a significant increase in plant biomass under both experimental conditions; we observed an increase in photosynthesis and in the endogenous contents of gibberellin, auxin, and cytokinin, while a decrease in ethylene levels was noted. VOCs emitted by SYST2 were identified through gas chromatography-mass spectrometry analysis. Of 11 VOCs tested in glass jars containing plants in test tubes, only two, albuterol and 1,3-propanediole, were found to promote plant growth. Furthermore, tomato plants showed differential expression of genes involved in auxin (
), gibberellin (
), cytokinin (
), expansin (
), and ethylene (
) biosynthesis or metabolism in roots and leaves in response to
SYST2 VOCs. Our findings suggest that SYST2-derived VOCs promote plant growth by triggering growth hormone activity, and provide new insights into the mechanism of plant growth promotion by bacterial VOCs.
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