Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically-Stable Low-Temperature Lithium-Ion Batteries.

Graphite (Gr)-based lithium-ion batteries with admirable electrochemical performance below -20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+-solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically-stable solid electrolyte interphase (SEI) without compromising strong Li+-solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature-dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low-temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e-) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4-based, inorganics-enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e- blocking and rapid desolvation, and as a result, much suppressed Li-metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low-temperature battery performances. Overall, our work originally provides visualized guides to improve low-temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.

Mitigating Electron Leakage of Solid Electrolyte Interface for Stable Sodium-Ion Batteries.

The interfacial stability is highly responsible for the longevity and safety of sodium ion batteries (SIBs). However, the continuous solid-electrolyte interphase(SEI) growth would deteriorate its stability. Essentially, the SEI growth is associated with the electron leakage behavior, yet few efforts have tried to suppress the SEI growth, from the perspective of mitigating electron leakage. Herein, we built two kinds of SEI layers with distinct growth behaviors, via the additive strategy. The SEI physicochemical features (morphology and componential information) and SEI electronic properties (LUMO level, band gap, electron work function) were investigated elaborately. Experimental and calculational analyses showed that, the SEI layer with suppressed growth delivers both the low electron driving force and the high electron insulation ability. Thus, the electron leakage is mitigated, which restrains the continuous SEI growth, and favors the interface stability with enhanced electrochemical performance.

[Research progress of Angelicae Sinensis Radix and predictive analysis on its quality markers].

Angelicae Sinensis Radix, as a medicinal and edible Chinese medicinal herb, is widely used in clinical practice. It is mainly cultivated in Minxian, Tanchang, Zhangxian and Weiyuan counties of Gansu province. In recent years, with the comprehensive and in-depth study of Angelicae Sinensis Radix in China and abroad, its chemical composition, pharmacological effects and application and development have attracted much attention. In this study, the chemical composition, traditional efficacy, and modern pharmacological effects of Angelicae Sinensis Radix were summarized. On this basis, combined with the core concept of quality markers(Q-markers), the Q-markers of Angelicae Sinensis Radix were discussed from the aspects of mass transfer and traceability and chemical composition specificity, availability, and measurability, which provided scientific basis for the quality evaluation of Angelicae Sinensis Radix.

In†Situ Scanning Tunneling Microscopy of Cobalt-Phthalocyanine-Catalyzed CO2 Reduction Reaction.

We report a molecular investigation of a cobalt phthalocyanine (CoPc)-catalyzed CO2 reduction reaction by electrochemical scanning tunneling microscopy (ECSTM). An ordered adlayer of CoPc was prepared on Au(111). Approximately 14 % of the adsorbed species appeared with high contrast in a CO2 -purged electrolyte environment. The ECSTM experiments indicate the proportion of high-contrast species correlated with the reduction of CoII Pc (-0.2 V vs. saturated calomel electrode (SCE)). The high-contrast species is ascribed to the CoPc-CO2 complex, which is further confirmed by theoretical simulation. The sharp contrast change from CoPc-CO2 to CoPc is revealed by in situ ECSTM characterization of the reaction. Potential step experiments provide dynamic information for the initial stage of the reaction, which include the reduction of CoPc and the binding of CO2 , and the latter is the rate-limiting step. The rate constant of the formation and dissociation of CoPc-CO2 is estimated on the basis of the in situ ECSTM experiment.

General Space-Confined On-Substrate Fabrication of Thickness-Adjustable Hybrid Perovskite Single-Crystalline Thin Films.

Organic-inorganic hybrid perovskite single-crystalline thin films (SCTFs) are promising for enhancing photoelectric device performance due to high carrier mobility, long diffusion length, and carrier lifetime. However, bulk perovskite single crystals available today are not suitable for practical device application due to the unfavorable thickness. Herein, we report a facile space-confined solution-processed strategy to on-substrate grow various hybrid perovskite SCTFs in a size of submillimeter with adjustable thicknesses from nano- to micrometers. These SCTFs exhibit photoelectric properties comparable to bulk single crystals with low defect density and good air stability. The clear thickness-dependent colors allow fast visual selection of SCTFs with a suitable thickness for specific device application. The present substrate-independent growth of perovskite SCTFs opens up opportunities for on-chip fabrication of diverse high-performance devices.

The intramolecular H-bonding effect on the growth and stability of Schiff-base surface covalent organic frameworks.

The introduction of intramolecular H-bonding by adding -OH functionalities adjacent to the Schiff base centers is considered to be a useful strategy to enhance the stability and crystallinity of bulk covalent organic frameworks (COFs). However, the influence of intramolecular H-bonding on the synthesis of surface COFs (SCOFs) have been barely explored. Herein, SCOFs based on the Schiff-base reaction between 1,3,5-tris(4-aminophenyl)benzene (TAPB) and terephthalaldehydes with symmetry or asymmetrically substituted hydroxyl functional groups are designed. In the absence of a solvent, hydroxyl substituents can be easily oxidized; thus argon protection is required to obtain high-quality SCOFs. Besides, an extended network with uniform pores can be achieved in spite of the symmetry of substituents. Both experimental results and theoretical calculations show that the influence of intramolecular hydrogen bonding on surface synthesis is not as important as that in bulk phase synthesis because the substrate itself can lead to the complanation of adsorbed molecules. The existence of intramolecular H-bonding can enhance the stability of the network in both acid and alkali environments.

Formation of Halogen Bond-Based 2D Supramolecular Assemblies by Electric Manipulation.

Halogen bonding has attracted much attention recently as an important driving force for supramolecular assembly and crystal engineering. Herein, we demonstrate for the first time the formation of a halogen bond-based open porous network on a graphite surface using ethynylpyridine and aryl-halide based building blocks. We found that the electrical stimuli of a scanning tunneling microscopy (STM) tip can induce the formation of a binary supramolecular structure on the basis of halogen bond formation between terminal pyridyl groups and perfluoro-iodobenzene. This electrical manipulation method can be applied to engineer a series of linear or porous structures by selecting halogen bond donor and acceptor fragments with different symmetries, as the directional interactions ultimately determine the structural outcome.

Direct probing of the structure and electron transfer of fullerene/ferrocene hybrid on Au(111) electrodes by in situ electrochemical STM.

The electron donor-acceptor dyads are an emerging class of materials showing important applications in nonlinear optics, dye-sensitized solar cells, and molecular electronics. Investigation of their structure and electron transfer at the molecular level provides insights into the structure-property relationship and can benefit the design and preparation of electron donor-acceptor dyad materials. Herein, the interface adstructure and electron transfer of buckyferrocene Fe(C60Me5)Cp, a typical electron donor-acceptor dyad, is directly probed using in situ electrochemical scanning tunneling microscopy (STM) combined with theoretical simulations. It is found that the adsorption geometry and assembled structure of Fe(C60Me5)Cp is significantly affected by the electrochemical environments. In 0.1 M HClO4 solution, Fe(C60Me5)Cp forms well-ordered monolayers and multilayers on Au(111) surfaces with molecular dimer as the building block. In 0.1 M NaClO4 solution, typical six-fold symmetric close-packed monolayer with vertically adsorbed Fe(C60Me5)Cp is formed. Upon electrochemical oxidation, the oxidized Fe(C60Me5)Cp shows higher brightness in an STM image, which facilitates the direct visualization of the interfacial electrochemical electron transfer process. Theoretical simulation indicates that the electrode potential-activated, one-electron transfer from Fe(C60Me5)Cp to the electrode leads to the change of the delocalization character of the frontier orbital in the molecule, which is responsible for the STM image contrast change. This result is beneficial for understanding the structure and property of single electron donor-acceptor dyads. It also provides a direct approach to study the electron transfer of electron donor-acceptor compounds at the molecular level.

Isomeric routes to Schiff-base single-layered covalent organic frameworks.

With graphene-like topology and designable functional moieties, single-layered covalent organic frameworks (sCOFs) have attracted enormous interest for both fundamental research and application prospects. As the growth of sCOFs involves the assembly and reaction of precursors in a spatial defined manner, it is of great importance to understand the kinetics of sCOFs formation. Although several large families of sCOFs and bulk COF materials based on different coupling reactions have been reported, the synthesis of isomeric sCOFs by exchanging the coupling reaction moieties on precursors has been barely explored. Herein, a series of isomeric sCOFs based on Schiff-base reaction is designed to understand the effect of monomer structure on the growth kinetics of sCOFs. The distinctly different local packing motifs in the mixed assemblies for the two isomeric routes closely resemble to those in the assemblies of monomers, which affect the structural evolution process for highly ordered imine-linked sCOFs. In addition, surface diffusion of monomers and the molecule-substrate interaction, which is tunable by reaction temperature, also play an important role in structural evolutions. This study highlights the important roles of monomer structure and reaction temperature in the design and synthesis of covalent bond connected functional nanoporous networks.

Electrostatic-interaction-induced molecular deposition of a hybrid bilayer on Au(111): a scanning tunneling microscopy study.

Hybrid bilayers consisting of 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and meso-tetra(4-pyridyl)porphine (TPyP) have been successfully constructed on Au(111) and investigated by electrochemical scanning tunneling microscopy (ECSTM). Under the guidance of the electrostatic interaction between negatively charged sulfonate groups and positively charged pyridyl groups, the underlying HPTS arrays act as templates for the deposition of cationic TPyPs, forming two types of TPyP/HPTS complex bilayers. The present work provides a feasible way to fabricate hybrid multilayers on the electrode surface via electrostatic interaction, which has great significance for the design of molecular nanodevices.

Adaptive reorganization of 2D molecular nanoporous network induced by coadsorbed guest molecule.

The ordered array of nanovoids in nanoporous networks, such as honeycomb, Kagome, and square, provides a molecular template for the accommodation of "guest molecules". Compared with the commonly studied guest molecules featuring high symmetry evenly incorporated into the template, guest molecules featuring lower symmetry are rare to report. Herein, we report the formation of a distinct patterned superlattice of guest molecules by selective trapping of guest molecules into the honeycomb network of trimesic acid (TMA). Two distinct surface patterns have been achieved by the guest inclusion induced adaptive reconstruction of a 2D molecular nanoporous network. The honeycomb networks can synergetically tune the arrangement upon inclusion of the guest molecules with different core size but similar peripherals groups, resulting in a trihexagonal Kagome or triangular patterns.

Bilayer molecular assembly at a solid/liquid interface as triggered by a mild electric field.

The construction of a spatially defined assembly of molecular building blocks, especially in the vertical direction, presents a great challenge for surface molecular engineering. Herein, we demonstrate that an electric field applied between an STM tip and a substrate triggered the formation of a bilayer structure at the solid-liquid interface. In contrast to the typical high electric-field strength (10(9)  V m(-1) ) used to induce structural transitions in supramolecular assemblies, a mild electric field (10(5)  V m(-1) ) triggered the formation of a bilayer structure of a polar molecule on top of a nanoporous network of trimesic acid on graphite. The bilayer structure was transformed into a monolayer kagome structure by changing the polarity of the electric field. This tailored formation and large-scale phase transformation of a molecular assembly in the perpendicular dimension by a mild electric field opens perspectives for the manipulation of surface molecular nanoarchitectures.

Sustainable Recycling of Selenium-Based Optoelectronic Devices.

Selenium (Se), the world's oldest optoelectronic material, has been widely applied in various optoelectronic devices such as commercial X-ray flat-panel detectors and photovoltaics. However, despite the rare and widely-dispersed nature of Se element, a sustainable recycling of Se and other valuable materials from spent Se-based devices has not been developed so far. Here a sustainable strategy is reported that makes use of the significantly higher vapor pressure of volatile Se compared to other functional layers to recycle all of them from end-of-life Se-based devices through a closed-space evaporation process, utilizing Se photovoltaic devices as a case study. This strategy results in high recycling yields of ≈ 98% for Se and 100% for other functional materials including valuable gold electrodes and glass/FTO/TiO2 substrates. The refabricated photovoltaic devices based on these recycled materials achieve an efficiency of 12.33% under 1000-lux indoor illumination, comparable to devices fabricated using commercially sourced materials and surpassing the current indoor photovoltaic industry standard of amorphous silicon cells.

On-surface synthesis of single-layered two-dimensional covalent organic frameworks via solid-vapor interface reactions.

Surface covalent organic frameworks (SCOFs), featured by atomic thick sheet with covalently bonded organic building units, are promised to possess unique properties associated with reduced dimensionality, well-defined in-plane structure, and tunable functionality. Although a great deal of effort has been made to obtain SCOFs with different linkages and building blocks via both "top-down" exfoliation and "bottom-up" surface synthesis approaches, the obtained SCOFs generally suffer a low crystallinity, which impedes the understanding of intrinsic properties of the materials. Herein, we demonstrate a self-limiting solid-vapor interface reaction strategy to fabricate highly ordered SCOFs. The coupling reaction is tailored to take place at the solid-vapor interface by introducing one precursor via vaporization to the surface preloaded with the other precursor. Following this strategy, highly ordered honeycomb SCOFs with imine linkage are obtained. The controlled formation of SCOFs in our study shows the possibility of a rational design and synthesis of SCOFs with desired functionality.

Solution effect on diazonium-modified Au(111): reactions and structures.

Surface modifications of a Au(111) electrode with 4-bromobenzenediazonium tetrafluoroborate (BBD) in acetonitrile (ACN) and 0.1 M HClO4 have been characterized by scanning tunneling microscopy (STM). In ACN, STM results reveal the formation of disordered thin organic films. The involvement of the radical as an intermediate is evidenced by the negative effect of radical scavengers on organic thin film formation. In contrast, the 4,4'-dibromobiphenyl monolayer is observed when the aqueous solution is used as a medium to carry out the grafting experiment. The biphenyl compound is considered to be generated by a radical-radical coupling reaction.

In situ scanning tunneling microscopy investigation of subphthalocyanine and subnaphthalocyanine adlayers on a Au(111) electrode.

The adsorption behaviors of subphthalocyanine (SubPc) and subnaphthalocyanine (SubNc) on the Au(111) surface were investigated by electrochemical scanning tunneling microscopy (ECSTM). Two types of ordered adlayer structures of SubPc were observed at 550 mV versus the reversible hydrogen electrode (RHE). All of the SubPc molecules take the Cl-down adsorption configuration on Au(111) in both structures. The ordered adlayers exist in the potential range between 350 and 650 mV. The SubNc molecules adsorb on Au(111) in a less-ordered pattern than the SubPc molecules. The present work provides direct evidence for understanding the potential-controlled adsorption behaviors of SubPc and SubNc on the Au(111) surface.

Hydrogen bonding network of truxenone on a graphite surface studied with scanning tunneling microscopy and theoretical computation.

The self-assembly of truxenone on highly oriented pyrolytical graphite (HOPG) was investigated with scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Truxenone assembled into a dense hexagonal adlayer with large and near-perfect domains on the graphite surface. Two types of topography image of truxenone were observed in experiments. DFT modeling indicates the center-hole image represents the contour of the lowest unoccupied molecular orbital (LUMO) of truxenone while the propeller-like image is more complicated and can't be assigned simply to an individual molecular orbital. Truxenone trimer was proposed as the basic unit of the adlayer through analysis of STM images and molecular structure. The optimized structure of the truxenone trimer by DFT calculation revealed that the hydrogen bonding network exists in the adlayer, which is responsible for the excellent stability and perfect domains of the whole assembly. In addition, the preferred adsorption site of truxenone on graphite was determined on the basis of DFT calculations and STM images. The results are of significance in supramolecular engineering by self-assembly and device fabrication based on truxenone and its derivatives.

[Effects of hemoperfusion on the patients with acute toxication of 2, 4-dinitrophenol].

OBJECTIVE: To explore the management strategies of acute toxication of 2, 4-dinitrophenol by hemoperfusion. METHODS: A total of 14 patients with acute toxication of 2, 4-dinitrophenol were admitted on September 14, 2009. And they were divided into severe and mild groups according to the severity of clinical manifestation. All patients in both groups received 2-hour blood perfusion within 2 hour post-admission. Their clinical manifestations, laboratory parameters and 2, 4-dinitrophenol levels were carefully observed before and after each perfusion. And oxygenation, intravenous use of furosemide, corticosteroids and symptomatic therapies were simultaneously given to improve general conditions. RESULTS: In serious group, the levels of before and after the first perfusion were 28.21(15.56-45.23) and 16.11(10.10-27.52) mg/L (P < 0.05), respectively. In both groups, all levels of 2, 4-dinitrophenol were significantly reduced before and after each perfusion (all P < 0.05). The patients in severe group would get relieved after 3 vs 2 perfusions in mild group. In severe group, there was a remarked decrease in neutrophil and platelet count after perfusion than those in mild group. The liver enzymes and blood lipids in both groups after therapy significantly elevated than those before therapy (all P < 0.05). CONCLUSION: Crucial for managing acute toxication of 2, 4-dinitrophenol, early hemoperfusion reduces mortality.

Static magnetic field increases aerobic nitrogen removal from hypersaline wastewater in activated sludge with coexistence of fungi and bacteria.

Fungi have been found to exist in activated sludge treating saline wastewater, but their role in removing pollution has been neglected. This study explored the aerobic removal of total inorganic nitrogen (TIN) from saline wastewater under static magnetic fields (SMFs) with several strengths. Compared to the control, the aerobic removal of TIN was significantly increased by 1.47 times in 50 mT SMF, due to the increased dissimilation nitrogen removal by fungi and bacteria. Under SMF, fungal nitrogen dissimilation removal was significantly increased by 3.65 times. The fungal population size decreased, and its community composition changed significantly under SMF. In contrast, bacterial community composition and population remained relatively stable. Under SMFs, heterotrophic nitrification - aerobic denitrification bacteria Paracoccus and the fungi denitrifying Candida formed a synergistic interaction. This study elucidates the fungal role in aerobic TIN removal and provides an efficient solution to improve TIN removal from saline wastewater by SMF.

Promoting enrichment of sulfur-oxidizing autotrophic denitrifiers via static magnetic fields: Performance and mechanism of magnetic biological effects.

Sulfur-driven autotrophic denitrification (SADN) is a promising technology for nitrogen removal from wastewater. In this study, different-strength SMFs (0, 5, 20, 50, 70 mT) were evaluated to investigate the potential of external static magnetic field (SMF) for enriching sulfur-oxidizing autotrophic denitrifiers (SOAD). 50-mT and 70-mT SMFs were most suitable to accelerate the growth of SOAD and the elimination of non-SOAD. The relative abundance of Thiobacillus significantly increased (p < 0.01) from 6.26% in control reactor to 36.15% under 50 mT and 52.51% under 70 mT. Under 50 mT, Thiobacillus denitrificans accumulated most rapidly, with the largest population. Furthermore, functional gene forecast by high-throughput and metagenomic sequencing indicated that SMF changed the two-component system, the adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling system, the phosphotransferase system (PTS), as well as N/S-related enzymes to regulate stress-response and promote the growth of SOAD. The findings indicated that SMF accelerated the start-up of SADN.