Abstract
In order to improve the stability and safety of lithium (Li) metal anodes, an innovative artificial solid electrolyte interface (SEI) film of Li Poly (tert-butyl acrylate-co-ethyl ...acrylate-co-methacrylic acid) (LiPTBEM) has been designed. This thin and uniformly artificial SEI is stable, which can suppress the continuous side reactions between the electrolyte and Li metal, improve the stability of modified Li metal anodes, and achieve better electrochemical performance. Symmetric batteries with LiPTBEM exhibit significantly improved cycling stability, indicating that LiPTBEM is a promising artificial SEI film.
In a recent report, room-temperature vertical ferroelectricity was experimentally shown in WTe2 bilayer, while its mechanism of ferroelectric switching without vertical ion displacements remains ...unclarified. In this work, we reveal its origin by first-principles calculations that the polarization stems from uncompensated interlayer vertical charge transfer depending on in-plane translation, which can be switched upon interlayer sliding. The calculated results are consistent with experimental data, and a similar switching mechanism can be applied to a multilayer counterpart. Despite its small ferroelectric switching barrier and polarization, the in-plane rigidity of WTe2 layer gives rise to a high Curie temperature. A moire pattern of ferroelectric domain superlattice can be formed and tuned upon a small-angle twist of bilayer, which is unique compared with traditional ferroelectrics. Similar interlayer translational ferroelectricity may exist in a series of van der Waals bilayers or even bulk phases.
Recent research on ferroelectrics based on two‐dimensional (2D) materials may lead to a technological revolution, offering much higher density for integration as well as a better combination of ...semiconductor properties and non‐volatile memories at the nanoscale compared with traditional ferroelectrics. In addition, ferroelectricity can be much more robust than ferromagnetism in 2D. In this study, we review the studies on 2D ferroelectricity starting from 2013, which are mainly first‐principles predictions, including functionalization‐induced 2D ferroelectricity in prevalent non‐polar 2D materials as well as 2D intrinsic ferroelectricity, which are either in‐plane or vertical. Although the number of reports on 2D ferroelectricity is still small compared to the large amount of research on 2D ferromagnetism, the potential of these materials to unravel new science and technology has stimulated considerable interest in 2D ferroelectricity, making it a fast developing field. It is interesting to note that 2D ferroelectricity was experimentally realized a year before 2D ferromagnetism, and the large difference in the Curie temperatures of these materials has further demonstrated that 2D ferroelectricity could be much more robust than 2D ferromagnetism.
This article is categorized under:
Structure and Mechanism > Computational Materials Science
Ferroelectrics based on two‐dimensional materials may render a much better combination of non‐volatile memories and semiconductor circuits with much higher integration density.
Sewage treatment plants (STPs) and pharmaceutical manufactories (PMFs) are recognized as important reservoirs for aquatic pollution with antibiotics. Although the occurrence of multiple classes of ...antibiotics has been mostly reported for STPs and PMFs, knowledge on the effects of wastewater treatment processes on the removal of antibiotics is not well documented. In this study, wastewaters were collected from different treatment points of two STPs and two PMFs in eastern China. Thirty-seven antibiotics within the four classes of fluoroquinolones (FQs), macrolides (MACs), sulfonamides (SAs) and tetracyclines (TCs) were analyzed. Among the investigated antibiotics, 19–33 out of 37 target compounds were detected at least once in the STPs wastewaters ranging from low ng/L to approximately 12.7 μ/L. In the wastewater samples collected from PMFs, up to 34 antibiotics were present with detection frequencies up to 100%, showing generally higher concentrations (up to 19.0 μ/L) than those at the STPs. FQs and SAs were the dominant antibiotic families, which accounted for more than 90% of the total antibiotic concentration in the wastewaters. Moreover, the removal of antibiotics by anaerobic-anoxic-oxic (A2O), membrane bioreactor (MBR) and conventional activated sludge (CAS) systems was evaluated. The MBR system exhibited the best performance, mainly due to the processes of biodegradation and sorption during biological treatments. Notably, several SAs (SMP, SMZ) and FQs (CIN, ENO) antibiotics were consistently detected at concentration levels of μ/L in the effluent samples. The culturable antibiotic-resistance tests and risk assessment indicated that the antibiotic-contaminated effluents would facilitate the development of resistant bacteria and pose high toxicity to non-target organisms in the aquatic environment. Overall, the findings suggested an urgent need for improving the wastewater treatment technologies for simultaneous removal of different classes of antibiotics.
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•Thirty-seven antibiotics in four classes were studied in sewage and pharmaceutical wastewaters.•Raw and treated wastewaters were mainly contaminated by sulfonamides and fluoroquinolones.•Combination of AO and MBR treatments contributed to the best antibiotic removal of MBR system.•The final effluents demonstrated antibiotic resistance property and ecotoxicity.•Pharmaceutical manufactories are more serious sources of antibiotic pollution in waters.
The coefficients of piezoelectricity and thermal expansion are generally positive due to the bond anharmonicity. For converse piezoelectricity, the electrostrain obtained in prevalent ceramics is ...only around 1%. Here we propose that the coordination transition of metal cations may make a paradigm shift. Through first-principles calculations, we predict a series of low-energy phases with distinct coordinations for Ag ions in superionic conductor AgCrX2 (X = S, Se), including ferroelectric and nonpolar phases with distinct interlayer distances. The mobile feature of Ag ions, which can be attributed to its complex coordination chemistry, can facilitate transformation between various coordination phases. Such facile transitions with ultralow barriers can be driven by applying either pressure, an electric field, or a change in temperature, giving rise to various exotic effects, including electrostrain, negative piezoelectricity, and negative thermal expansion. All with unprecedented giant constants, those mechanisms stem from the coordination transitions, distinct from the weak linear effects in previous reports.
In a recent report, room-temperature vertical ferroelectricity was experimentally shown in WTe
bilayer, while its mechanism of ferroelectric switching without vertical ion displacements remains ...unclarified. In this work, we reveal its origin by first-principles calculations that the polarization stems from uncompensated interlayer vertical charge transfer depending on in-plane translation, which can be switched upon interlayer sliding. The calculated results are consistent with experimental data, and a similar switching mechanism can be applied to a multilayer counterpart. Despite its small ferroelectric switching barrier and polarization, the in-plane rigidity of WTe
layer gives rise to a high Curie temperature. A moire pattern of ferroelectric domain superlattice can be formed and tuned upon a small-angle twist of bilayer, which is unique compared with traditional ferroelectrics. Similar interlayer translational ferroelectricity may exist in a series of van der Waals bilayers or even bulk phases.
Although the quantum anomalous Hall effect was verified in 2013, presently its experimental realization is limited to doped magnetic topological insulators under extremely low temperature, while its ...theoretical existence is limited within doped or functionalized materials, or heterostructures. Based on first-principles calculations, LaCl and LaBr monolayer and bulk forms, which were fabricated in 1980s (Mattausch et al 1980 Z. Anorg. Allg. Chem. 466 7-22; Araujo and Corbett 1981 Inorg. Chem. 20 3082-6), are both revealed to exhibit intrinsic 2D/3D quantum anomalous Hall effect with energy gaps up to 36 meV. These simple binary compounds are also revealed to be ferromagnets with high Curie temperature, which guarantees that the quantum anomalous Hall effect survives at ambient condictions. Besides holding promise for low-dissipation electronics and quantum computing, this proposal realizes 3D quantum anomalous Hall effect.
Solid desiccant humidity pump is an emerging device that enables moisture transport through the inverse gradient of vapor concentration, featuring refrigerant-free, no moveable parts and compact ...structure. However, traditional materials (e.g. silica gel and zeolite) have made this device less competent due to the poor sorption performance and strict regeneration conditions. In this respect, metal-organic frameworks, representing the cutting edge of the available porous materials, are expected to upgrade the performance of this device. In this study, the optimization of a novel MOF-based humidity pump (MOF-HP) was carried out. We used the CFD method to analyze the hygrothermal performance of a MOF-HP. The model built up the relationship among humid air, desiccant, and heat sink and then coupled the subdomains of the fluid flow, heat transfer, and specie transport. The model of MOF-HP under different operation conditions was validated by experimental tests. Based on the measured results, the discrepancies were maintained under 15%. A parametric optimization was subsequently carried out to enhance the hygrothermal performance of MOF-HP. This dimensional analysis provides some guidelines for MOF-HP design with the most suitable geometry. The optimized configuration is estimated to have a 1.59 times improvement in moisture removal capacity over the original design.
•A novel MOF humidity pump is constructed for energy-efficient localized moisture control.•A CFD approach is adopted to optimize the geometry and performance of MOF-HP.•The governing equations (i.e., mass, momentum, energy and species conservation) are highly coupled.•Parametric study discloses the correlation between the fluid flow and the mass transport.•The optimized configuration is estimated to have a 1.59 times improvement in moisture removal capacity.
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