共查询到20条相似文献,搜索用时 15 毫秒
1.
Shien Zhong Yongshi Yu Yi Yang Dr. Yu Yao Lifeng Wang Dr. Shengnan He Dr. Yaxiong Yang Dr. Lin Liu Prof. Wenping Sun Dr. Yuezhan Feng Prof. Hongge Pan Prof. Xianhong Rui Prof. Yan Yu 《Angewandte Chemie (International ed. in English)》2023,62(18):e202301169
Carbonate electrolytes have excellent chemical stability and high salt solubility, which are ideally practical choice for achieving high-energy-density sodium (Na) metal battery at room temperature. However, their application at ultra-low temperature (−40 °C) is adversely affected by the instability of solid electrolyte interphase (SEI) formed by electrolyte decomposition and the difficulty of desolvation. Here, we designed a novel low-temperature carbonate electrolyte by molecular engineering on solvation structure. The calculations and experimental results demonstrate that ethylene sulfate (ES) reduces the sodium ion desolvation energy and promotes the forming of more inorganic substances on the Na surface, which promote ion migration and inhibit dendrite growth. At −40 °C, the Na||Na symmetric battery exhibits a stable cycle of 1500 hours, and the Na||Na3V2(PO4)3 (NVP) battery achieves 88.2 % capacity retention after 200 cycles. 相似文献
2.
Dr. Narayan Sinha Dr. Dorus Heijnen Prof. Ben L. Feringa Prof. Michael G. Organ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(39):9180-9184
The coupling of organolithium reagents, including strongly hindered examples, at cryogenic temperatures (as low as −78 °C) has been achieved with high-reactivity Pd-NHC catalysts. A temperature-dependent chemoselectivity trigger has been developed for the selective coupling of aryl bromides in the presence of chlorides. Building on this, a one-pot, sequential coupling strategy is presented for the rapid construction of advanced building blocks. Importantly, one-shot addition of alkyllithium compounds to Pd cross-coupling reactions has been achieved, eliminating the need for slow addition by syringe pump. 相似文献
3.
The hydrolytic behavior of antimonic acid, Sb(OH)5o, was experimentally investigated, at fixed temperatures within the range 10–40 °C, by both titration of dilute Na-antimonate
solutions with HClO4 and single-point pH measurements of diluted Sb(OH)5o solutions. The thermodynamic constants, K
a, for the reaction:
were derived at different controlled temperatures, based on pH measurements, applying suitable mass and electrical balances
and correcting the concentrations of ionic species for medium effects. From the resulting log 10
K
a values, those of the corresponding isocoulombic equilibrium reaction:
were computed and used to derive its thermodynamic properties. These were finally combined with the corresponding thermodynamic
properties of the water association reaction, to obtain robust estimations of ΔG
ro, ΔS
ro and ΔH
ro for the ionogenic reaction. These are the first thermodynamic data at temperatures different from 25 °C for the ionization
reaction of Sb(OH)5o. The results of the present work confirm that Sb(OH)5o is a moderately weak and monoprotic acid with a pK
a of 2.848 at 25 °C. 相似文献
4.
Matvei Zinkevitch Norbert Mattern Horst Wendrock Klaus Wetzig 《Mikrochimica acta》2000,133(1-4):243-251
Phase equilibria in the ternary system Fe-Gd-Mo at 600 °C were determined. The phase composition for different element concentrations
were quantitatively determined from the diffraction patterns by means of the multi-phase Rietveld-refinement as well as through
evaluation of the microstructure images obtained by the scanning electron microscopy. Both methods are compared with each
other with respect to their precision and limitations. The complete isothermal section at 600 °C includes one ternary phase
τ (ThMn12-type of structure), four pseudo-binary phases (Fe,Mo)17Gd2, (Fe,Mo)23Gd6, (Fe,Mo)3Gd and (Fe,Mo)2Gd and binary phases Fe2Mo and μ-(Fe,Mo). The ternary phase τ forms the tie-lines with the solid solutions α-Fe, (Mo)-, Fe2Mo and μ-(Fe,Mo) phases as well as with the pseudo-binary Fe-Gd compounds. Three phases (Fe,Mo)2Gd, (Mo) and Gd coexist in a wide concentrations range. The homogeneity region of the ternary phase τ as well as the solubilities
of the third element in the binary phases were determined. 相似文献
5.
Xuejun Lu Zhenhua Liu Amardeep Amardeep Zhenrui Wu Li Tao Keqi Qu Hao Sun Yulong Liu Jian Liu 《Angewandte Chemie (International ed. in English)》2023,62(33):e202307475
The brain-storm of designing low-cost and commercialized eutectic electrolytes for zinc (Zn)-based electrochemical energy storage (ZEES) remains unresolved and attractive, especially when implementing it at low temperatures. Here, we report an appealing layout of advancing chlorine-functionalized eutectic (Cl-FE) electrolytes via exploiting Cl anion-induced eutectic interaction with Zn acetate solutions. This novel eutectic liquid shows high affinity to collaborate with 1,3-dioxolane (DOL) and is prone to constitute Cl-FE/DOL-based electrolytes with a unique inner/outer eutectic solvation sheath for the better regulation of Zn-solvating neighboring and reconstruction of H-bonding. The side reactions are effectively restricted on Zn anodes and a high Coulombic efficiency of 99.5 % can be achieved over 1000 cycles at −20 °C with Zn//Cu setups. By prototyping scale-up Zn-ion pouch cells using the optimal eutectic liquid of 3ZnOAc1.2Cl1.8-DOL, we obtain improved electrochemical properties at −20 °C with a high capacitance of 203.9 F g−1 at 0.02 A g−1 in a range of 0.20–1.90 V and long-term cycling ability with 95.3 % capacitance retention at 0.2 A g−1 over 3,000 cycles. Overall, the proposal of ideal Cl-FE/DOL-based electrolytes guides the design of sub-zero and endurable aqueous ZEES devices and beyond. 相似文献
6.
In order to synthesize the high temperature solid lubricating film by gas-phase polymerization at 500?°C with two kinds of gasified monomers for use in airplane and rocket engines, the polymerizing activity of terephthaloyl chloride (TPC) and p-phenylenediamine (PPD) at 500?°C and their polymerized product poly-p-phenyleneterephthamide (PPTA) as well as its decomposed solid residues were researched. It was proved by FT-IR and 1HNMR on the solid residues after the 10?min experiment of the both monomers in muffle furnace at 500?°C and PPTA synthesized by conventional method that at 500?°C the polymerization tendency of these monomers should trump their decomposition tendency. The solid residues after the 10?min experiment mainly consisted of polymerized products which would decline as the experimental period increases, while the content of decomposed and carbonized products would raise. FT-IR and elemental analysis revealed a similar structure of the solid residues after the both monomers or PPTA calcined for 60?min at 500?°C, which further demonstrated the polymerized products would degrade, decompose and carbonize after the prophase polymerization. Finally, effects of experimental temperature and monomers molar ratio on amounts and structures of the solid residues were discussed to propose preliminary mechanisms of polymerization and decomposition. 相似文献
7.
Li-Peng Hou Xue-Qiang Zhang Bo-Quan Li Prof. Qiang Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(35):15221-15225
Stable operation at elevated temperature is necessary for lithium metal anode. However, Li metal anode generally has poor performance and safety concerns at high temperature (>55 °C) owing to the thermal instability of the electrolyte and solid electrolyte interphase in a routine liquid electrolyte. Herein a Li metal anode working at an elevated temperature (90 °C) is demonstrated in a thermotolerant electrolyte. In a Li|LiFePO4 battery working at 90 °C, the anode undergoes 100 cycles compared with 10 cycles in a practical carbonate electrolyte. During the formation of the solid electrolyte interphase, independent and incomplete decomposition of Li salts and solvents aggravate. Some unstable intermediates emerge at 90 °C, degenerating the uniformity of Li deposition. This work not only demonstrates a working Li metal anode at 90 °C, but also provides fundamental understanding of solid electrolyte interphase and Li deposition at elevated temperature for rechargeable batteries. 相似文献
8.
Dr. Tobias Brückner Benedikt Ritschel Prof. Dr. J. Oscar C. Jiménez-Halla Dr. Felipe Fantuzzi Dario Duwe Christian Markl Dr. Rian D. Dewhurst Maximilian Dietz Prof. Dr. Holger Braunschweig 《Angewandte Chemie (International ed. in English)》2023,62(5):e202213284
Carbene-stabilized diborynes of the form LBBL (L=N-heterocyclic carbene (NHC) or cyclic alkyl(amino)carbene (CAAC)) induce rapid, high yielding, intermolecular ortho-C−H borylation at N-heterocycles at room temperature. A simple pyridyldiborene is formed when an NHC-stabilized diboryne is combined with pyridine, while a CAAC-stabilized diboryne leads to activation of two pyridine molecules to give a tricyclic alkylideneborane, which can be forced to undergo a further H-shift resulting in a zwitterionic, doubly benzo-fused 1,3,2,5-diazadiborinine by heating. Use of the extended N-heteroaromatic quinoline leads to a borylmethyleneborane under mild conditions via an unprecedented boron-carbon exchange process. 相似文献
9.
The mean ionic activity coefficients for sodium chloride in the NaCl+H2O binary system have been experimentally determined at 298.15 K, from electromotive force measurements of the cell:
The electrolyte molality, m, ranged from 0.01 to 3 mol⋅kg−1. The measurements of electromotive force were carried out on solutions containing pure water as solvent, or a mix of water
and “extremely diluted solutions” (EDS), obtained using the iterative procedure of successive dilutions and succussions of
Homeopathic Medicine, at the same concentration of sodium chloride. The measurements of the mean activity coefficient of sodium
chloride, on the solutions containing the EDS, showed evidence of some relevant differences compared to those with just water
as solvent. In the performed experiments, the differences in electromotive force between the two systems must be attributed
substantially to a difference in the activity of the solute between the two solvents.
The analysis of the activity coefficients was interpreted by considering the different kinds of interactions that can take
place in the mixed system, due to the presence of molecular aggregates of water molecules, i.e., dissipative structures. 相似文献
10.
Nan Wang Xiaoli Dong Bingliang Wang Zhaowei Guo Zhuo Wang Renhe Wang Xuan Qiu Prof. Yonggang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(34):14685-14691
Aqueous zinc (Zn) batteries have been considered as promising candidates for grid-scale energy storage. However, their cycle stability is generally limited by the structure collapse of cathode materials and dendrite formation coupled with undesired hydrogen evolution on the Zn anode. Herein we propose a zinc–organic battery with a phenanthrenequinone macrocyclic trimer (PQ-MCT) cathode, a zinc-foil anode, and a non-aqueous electrolyte of a N,N-dimethylformamide (DMF) solution containing Zn2+. The non-aqueous nature of the system and the formation of a Zn2+–DMF complex can efficiently eliminate undesired hydrogen evolution and dendrite growth on the Zn anode, respectively. Furthermore, the organic cathode can store Zn2+ ions through a reversible coordination reaction with fast kinetics. Therefore, this battery can be cycled 20 000 times with negligible capacity fading. Surprisingly, this battery can even be operated in a wide temperature range from −70 to 150 °C. 相似文献
11.
Lu Luo Shuai Tang Jiangyue Wu Shiwei Jin Hua Zhang 《Chemical record (New York, N.Y.)》2023,23(4):e202300023
Aromatic organoboron compounds are highly valuable building blocks in organic chemistry. They were mainly synthesized through aromatic C−H and C−Het borylation, in which transition metal-catalysis dominate. In the past decade, with increasing attention to sustainable chemistry, numerous transition metal-free C−H and C−Het borylation transformations have been developed and emerged as efficient methods towards the synthesis of aromatic organoboron compounds. This account mainly focuses on recent advances in transition metal-free aromatic C−H, C−N, C−S, and C−O borylation transformations and provides insights to where further developments are required. 相似文献
12.
Dr. Tatyana S. Koptseva Dr. Vladimir G. Sokolov Prof. Dr. Sergey Yu. Ketkov Dr. Elena A. Rychagova Anton V. Cherkasov Prof. Dr. Alexandra A. Skatova Prof. Dr. Igor L. Fedushkin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(18):5745-5753
The reaction of dialane [LAl-AlL] ( 1 ; L=dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene, dpp-bian) with carbon dioxide results in two different products depending on solvent. In toluene at temperatures of about 0 °C, the reaction gives cycloadduct [L(CO2)Al-Al(O2C)L] ( 2 ), whereas in diethyl ether, the reaction affords oxo-bridged carbamato derivative [L(CO2)(Et2O)Al(μ-O)AlL] ( 3 ). The DFT and QTAIM calculations provide reasonable explanations for the reversible formation of complex 2 in the course of two subsequent (2+4) cycloaddition reactions. Consecutive transition states with low activation barriers were revealed. Also, the DFT study demonstrated a crucial effect of diethyl ether coordination to aluminium on the reaction of dialane 1 with CO2. The optimized structures of key intermediates were obtained for the reactions in the presence of Et2O; calculated thermodynamic parameters unambiguously testify the irreversible formation of the product 3 . 相似文献
13.
The temperature and pressure dependences of pK for acridine ion ionization were determined up to 200 °C and 2000 bar. The UV-Vis measurements at high temperatures and pressures
were conducted in flow-through spectrophotometric cells. Two independent series of experiment were performed: one in a Ti–Pd
cell with silica quartz windows for measurements in the ultraviolet region, and another in a Ti grade 5 cell with sapphire
windows for use at higher pressures, which permitted measurements in the visible region. Combined chemometric and thermodynamic
analyses of the UV-Vis spectrophotometric data were used to extract the ionization constants as well as the changes in molar
volume ΔV° for acridine protonation as functions of temperature and pressure. Values of pK decrease from 5.52 to 3.74 with increasing temperature from 25 to 200 °C at saturated water-vapor pressure. The pressure
dependence of acridinium ion ionization is small (e.g., pK=5.5 at 25 °C and 2000 bar) and is characterized by positive ΔV°≤1.2 cm3⋅mol−1, which is not surprising for this type of isocoulombic reaction involving a large molecule. 相似文献
14.
A. Perez G. Vanermen B. Noten T. P. J. Linsinger 《Accreditation and quality assurance》2016,21(1):57-63
During the post-certification stability monitoring of the certified reference material (CRM) BCR-551 (DNPH derivatives dissolved in acetonitrile), a decreased concentration of one of the analytes of this CRM, the DNPH-formaldehyde derivative, was detected in reference samples (stored at ?70 °C), while the concentration of normal “on-sale” samples (stored at ?20 °C) remained stable. This behaviour is contrary to the expectation of better stability at lower temperatures. Apparently, the DNPH-formaldehyde derivative reacts with dinitrophenylhydrazine (DNPH) remaining from the synthesis phase to produce two new substances. These substances have been identified as C13H12N8O8 (substance 1) and C20H16N12O12 (substance 2) which, based on their structure, are suggested to be produced consecutively: DNPH + DNPH-formaldehyde derivative → substance 1 and substance 1 + DNPH-formaldehyde derivative → substance 2. Since acetonitrile freezes at ?45 °C, reference samples are frozen at ?70 °C, while normal samples are still liquid at ?20 °C. We believe that this leads to a cryo-concentration of the solutes above the eutectic point and thus to an increased reaction rate in the reference samples. This case demonstrates that care should be taken when extrapolating stability results towards conditions that never have been tested, especially if phase transitions are involved, even at temperature as low as ?70 °C. Furthermore, a slower degradation rate at lower temperatures can be overcompensated by a higher concentration due to cryo-concentration above the eutectic temperature. 相似文献
15.
Julia Struwe Dr. Korkit Korvorapun Agnese Zangarelli Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(65):16237-16241
The ruthenium-catalyzed synthesis of diarylmethane compounds was realized under exceedingly mild photoredox conditions without the use of exogenous photocatalysts. The versatility and robustness of the ruthenium-catalyzed C−H benzylation was reflected by an ample scope, including multifold C−H functionalizations, as well as transformable pyrazoles, imidates and sensitive nucleosides. Mechanistic studies were indicative of a photoactive cyclometalated ruthenium complex, which also enabled versatile C−H allylations. 相似文献
16.
Jana Ehlerova Liliana Trevani Josef Sedlbauer Peter Tremaine 《Journal of solution chemistry》2008,37(6):857-874
The UV-visible spectra of aqueous o-, m-, and p-nitrophenol were measured as a function of pH at temperatures from 50 to 225 °C at a pressure of 7 MPa. These were used to
determine equilibrium constants for the acid ionization reaction of each isomer. The new results were combined with literature
data on the ionization of nitrophenols and used for parameter optimization in the thermodynamic model of Marshall and Franck
(J. Phys. Chem. Ref. Data 10:295–304, [1981]), to describe the dependence of ionization properties on temperature and pressure. The model yields predictions of the ionization
constants for o-, m-, and p-nitrophenol, log 10
K
a, to at least 250 °C and 20 MPa with an estimated uncertainty in log 10
K
a of less than ±0.06. 相似文献
17.
The stoichiometric pK
1
*
and pK
2
*
for the ionization of sulfurous acid has been determined from emf measurements in NaCl solutions with varying concentrations of added MgCl2 (m=0.1, 0.2 and 0.3) from I=0.5 to 6.0 molal at 25°C. These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interaction of Mg2+ with SO2 and HSO
3
–
yielded =0.085±0.004, (0) = 0.35±0.02, (1) = 1.2±0.04, and C = –0.072±0.007. The Pitzer parameters (0) = –2.8±0.4, (1) = 12.9±2.9 and (2) = –2071±57 have been determined for the interactions of Mg2+ with SO
3
2–
. The calculated values of pK
1
*
and pK
2
*
using Pitzer's equations reproduce the measured values to within ±0.04 pK units. The ion pairing model with log KMgSO3=2.36±0.02 and logMgSO3 = 0.1021, reproduces the experimental values of pK
2
*
to ±0.01. These results demonstrate that treating the data by considering the formation of MgSO3 yields a better fit of the experimental measurements with fewer adjustable parameters. With these derived coefficients obtained from the Pitzer equations and the ion pairing model, it is possible to make reliable estimates of the activity coefficients of HSO
3
–
and SO
3
2–
in seawater, brines and marine aerosols containing Mg2+ ions. 相似文献
18.
Dr. Yan Xue Dr. Huanhuan Li Yuting Zhang Prof. Kelei Zhuo Prof. Guangyue Bai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13274-13281
The construction of potential electrode materials with wide temperature property for high-energy-density secondary batteries has attracted great interest in recent years. Herein, a hybrid electrode, consisting of a nitrogen-doped carbon/α-MnS/flake graphite composite (α-MnS@N-C/FG), is prepared through a post-sulfurization route. In the α-MnS@N-C/FG composite, α-MnS nanoparticles wrapped by the N−C layer are uniformly embedded onto FG, forming a novel nanofoam structure. The as-obtained α-MnS@N-C/FG shows excellent lithium/sodium storage performance, with a specific capacity of 712 mA h g−1 in the 700th cycle at 1.0 A g−1 or 186.4 mA h g−1 in the 100th cycle at 100 mA g−1 using lithium or sodium foil as the counter electrode, respectively. Moreover, even operated at −20 °C, the α-MnS@N-C/FG can still attain a high specific capacity of 350 mA h g−1 after 50 cycles at 100mA g−1 for LIBs. This exceptional electrochemical response is attributed to the synergetic effect of the smart design of a hybrid nanofoam structure, in which the FG skeleton and N-C coating layer can significantly enhance the conductivity of the whole electrode from bottom to top. Accordingly, the enhanced redox kinetics endow the electrode with pseudocapacitive-dominated electrochemical behavior, leading to fast electrode reactions and robust structural stability in the whole electrode. 相似文献
19.
Dr. Yang Wei Melissa Conklin Prof. Dr. Yong Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202202006
Engineered heme protein biocatalysts provide an efficient and sustainable approach to develop amine-containing compounds through C−H amination. A quantum chemical study to reveal the complete heme catalyzed intramolecular C−H amination pathway and protein axial ligand effect was reported, using reactions of an experimentally used arylsulfonylazide with hemes containing L=none, SH−, MeO−, and MeOH to simulate no axial ligand, negatively charged Cys and Ser ligands, and a neutral ligand for comparison. Nitrene formation was found as the overall rate-determining step (RDS) and the catalyst with Ser ligand has the best reactivity, consistent with experimental reports. Both RDS and non-RDS (nitrene transfer) transition states follow the barrier trend of MeO−<SH−<MeOH<None due to the charge donation capability of the axial ligand to influence the key charge transfer process as the electronic driving forces. Results also provide new ideas for future biocatalyst design with enhanced reactivities. 相似文献
20.
H. Bittner 《Monatshefte für Chemie / Chemical Monthly》1964,95(6):1514-1520
Ohne ZusammenfassungMit 4 Abbildungen 相似文献