Aqueous Zn batteries promise high energy density but suffer from Zn dendritic growth and poor low‐temperature performance. Here, we overcome both challenges by using an eutectic 7.6 m ZnCl2 aqueous ...electrolyte with 0.05 m SnCl2 additive, which in situ forms a zincophilic/zincophobic Sn/Zn5(OH)8Cl2⋅H2O bilayer interphase and enables low temperature operation. Zincophilic Sn decreases Zn plating/stripping overpotential and promotes uniform Zn plating, while zincophobic Zn5(OH)8Cl2⋅H2O top‐layer suppresses Zn dendrite growth. The eutectic electrolyte has a high ionic conductivity of ≈0.8 mS cm−1 even at −70 °C due to the distortion of hydrogen bond network by solvated Zn2+ and Cl−. The eutectic electrolyte enables Zn∥Ti half‐cell a high Coulombic efficiency (CE) of >99.7 % for 200 cycles and Zn∥Zn cell steady charge/discharge for 500 h with a low overpotential of 8 mV at 3 mA cm−2. Practically, Zn∥VOPO4 batteries maintain >95 % capacity with a CE of >99.9 % for 200 cycles at −50 °C, and retain ≈30 % capacity at −70 °C of that at 20 °C.
A highly reversible Zn anode working at low temperature is achieved by introducing SnCl2 into eutectic ZnCl2 aqueous electrolyte to form a zincophilic–zincophobic interfacial layer on the Zn anode in situ. The bottom layer of Sn facilitates uniform Zn deposition, while the top layer of zincophobic Zn5(OH)8Cl2 H2O facilitates Zn2+ diffusion and avoids Zn dendrites. The eutectic composition enhances the low temperature conductivity.
A long-standing challenge in material design is to overcome the conflict between strength and toughness, because they are generally mutually exclusive. To address this challenge, we rationally design ...cellulose-based nanopaper and investigate the dependence of their mechanical properties on constituent cellulose fiber size. Surprisingly, we find that both the strength and toughness of the nanopaper increase simultaneously (40 and 130 times, respectively) as the average diameter of constituent cellulose fibers decreases from 27 μm to 11 nm, suggesting the promising potential toward an anomalous but highly desirable scaling law: the smaller, the stronger and the tougher. There are abundant opportunities to use the fundamental bottom-up strategy to design a novel class of functional materials that are both strong and tough.
The quest for both strength and toughness is perpetual in advanced material design; unfortunately, these two mechanical properties are generally mutually exclusive. So far there exists only limited success of attaining both strength and toughness, which often needs material-specific, complicated, or expensive synthesis processes and thus can hardly be applicable to other materials. A general mechanism to address the conflict between strength and toughness still remains elusive. Here we report a first-of-its-kind study of the dependence of strength and toughness of cellulose nanopaper on the size of the constituent cellulose fibers. Surprisingly, we find that both the strength and toughness of cellulose nanopaper increase simultaneously (40 and 130 times, respectively) as the size of the constituent cellulose fibers decreases (from a mean diameter of 27 μm to 11 nm), revealing an anomalous but highly desirable scaling law of the mechanical properties of cellulose nanopaper: the smaller, the stronger and the tougher. Further fundamental mechanistic studies reveal that reduced intrinsic defect size and facile (re)formation of strong hydrogen bonding among cellulose molecular chains is the underlying key to this new scaling law of mechanical properties. These mechanistic findings are generally applicable to other material building blocks, and therefore open up abundant opportunities to use the fundamental bottom-up strategy to design a new class of functional materials that are both strong and tough.
Recently, we reported a dramatic solvent effect on the phosphorus hyperfine coupling constant aP of beta-phosphorylated six-membered ring nitroxides, that is, approximately 25G of difference in aP ...from n-hexane to water (Org. Biomol. Chem. 2016, 14, --1228-1292). In this article, we report on the effect of intramolecular hydrogen bonding (IHB) in three nitroxides exhibiting IHB between the hydroxyl and diethylphosphoryl groups and one exhibiting IHB between the hydroxyl group and the nitroxyl moiety. It is observed that for the first three nitroxides, aP increases with increasing polarity/polarizability and hydrogen bond donor (HBD) properties of the solvent (π* and alpha, respectively)--in sharp contrast to the data reported in the literature--and for the last nitroxide, aP decreases with π* and alpha. In fact, the occurrence of IHB induces a large strain, its suppression by hydrogen bond acceptor (HBA) solvents affords an increase in aP.
The synthesis of pyrido1,2‐abenzimidazole derivatives from the cobalt(III)‐catalyzed C−H activation and vinylene transfer of imidazo1,2‐apyridines with vinylene carbonate has been proposed. Most ...products of pyrido1,2‐abenzimidazoles were achieved in good yields under simple and easy‐to‐operate conditions. Scale‐up preparation and several preliminary mechanistic studies involving C−H bond activation and electronic effects between different substrates were also performed. This protocol offers an alternative approach for the synthesis of diverse useful pyrido1,2‐abenzimidazole derivatives.
The corrosion, parasitic reactions, and aggravated dendrite growth severely restrict development of aqueous Zn metal batteries. Here, we report a novel strategy to break the hydrogen bond network ...between water molecules and construct the Zn(TFSI)2‐sulfolane‐H2O deep eutectic solvents. This strategy cuts off the transfer of protons/hydroxides and inhibits the activity of H2O, as reflected in a much lower freezing point (<−80 °C), a significantly larger electrochemical stable window (>3 V), and suppressed evaporative water from electrolytes. Stable Zn plating/stripping for over 9600 h was obtained. Based on experimental characterizations and theoretical simulations, it has been proved that sulfolane can effectively regulate solvation shell and simultaneously build the multifunctional Zn‐electrolyte interface. Moreover, the multi‐layer homemade modular cell and 1.32 Ah pouch cell further confirm its prospect for practical application.
The Zn(TFSI)2‐sulfolane‐water hybrid electrolytes based on the deep eutectic solvents present an efficient strategy for hydrogen bond network reconstruction and multifunctional interfaces optimization, realizing highly reversible Zn plating/stripping and excellent electrochemical performance.
The novel self-healable waterborne polyurethanes (WPU) with the synergistic reversible units of aliphatic disulfide bonds and quadruple hydrogen bonding have been successfully prepared. The ...ureidopyrimidone (UPy) functional motifs were introduced into polymer backbones of polyurethane, where also placed the reversible disulfide bonds. The quadruple hydrogen bonds of UPy groups endowed the material a strong physical cross-linking network, which provided a superior Young's moduli. The features of dual dynamic structure could also produce a relatively low active energy of 36.1 kJ/mol, resulting in a good self-repairing efficiency of 94% under a mild condition. Furthermore, the influence of self-healing time and different repairing temperature on the healed performance was also systematically investigated. In order to describe the self-healing progress of multiple dynamic units, a physical model was used to study the evolution of self-repairing efficiency with variable healing time, indicating that quadruple H-bonding and disulfide bonds predominantly supported time dependent reconstruction of physically crosslinking network to recover the original mechanical property.
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•The self-healable waterborne polyurethanes contained synergistic dual reversible units.•The sample exhibited good mechanical properties as well as superior self-healing performance.•A physical equation was proposed to explain the evolution characteristics of dual self-healing units.
2D extended organic cocrystals were constructed using 1,4-diiodotetrafluorobenzene and aromatic aldehydes via I⋯Oaldehyde halogen bonds on an Au(111) surface. The competition and synergy of halogen ...bonds and hydrogen bonds in 2D co-crystallization were revealed by scanning tunneling microscopy.
A novel definition for the hydrogen bond is recommended here. It takes into account the theoretical and experimental knowledge acquired over the past century. This definition insists on some ...evidence. Six criteria are listed that could be used as evidence for the presence of a hydrogen bond.
Glassy polymers are extremely difficult to self-heal below their glass transition temperature (Tg) due to the frozen molecules. Here, we fabricate a series of randomly hyperbranched polymers (RHP) ...with high density of multiple hydrogen bonds, which show Tg up to 49 °C and storage modulus up to 2.7 GPa. We reveal that the hyperbranched structure not only allows the external branch units and terminals of the molecules to have a high degree of mobility in the glassy state, but also leads to the coexistence of “free” and associated complementary moieties of hydrogen bonds. The free complementary moieties can exchange with the associated hydrogen bonds, enabling network reconfiguration in the glassy polymer. As a result, the RHP shows amazing instantaneous self-healing with recovered tensile strength up to 5.5 MPa within 1 min, and the self-healing efficiency increases with contacting time at room temperature without the intervention of external stimuli.
The apelin-apelin receptor (APJ) system has been a promising biomolecular target participating crucially in several major disorders including cardiovascular diseases, neurodegenerative diseases, ...metabolic disorders, and lung, liver, and kidney-related diseases as well as in cancer. Though it is a promising therapeutic target for drug design for such diverse disease conditions, surprisingly no such molecular modeling study has been performed to date. This study reports the first predictive comparative multi-QSAR modeling analysis (like stepwise linear regression QSAR, MIA-QSAR, 3D-QSAR CoMFA, and CoMSIA) on a series of 4-pyrimidinone and 2-pyridinone-based APJ inhibitors to assimilate the knowledge regarding the crucial structural and physicochemical features responsible for the modulation of the APJ inhibitory effects. The statistically validated multi-QSAR modeling study unveils the importance of several crucial structural features responsible for modulating APJ inhibition. The presence of the 5-benzyl-1,3,4-oxadiazole ring, the higher number of hydrogen bond acceptor groups, and 4-chlorobenzyl, 4-bromobenzyl, and 2-methoxy groups may favor APJ inhibitory effects. However, bulky thiophenyl and
n
-butyl groups are detrimental to APJ inhibition. This current study may accelerate the process of the design and discovery of novel and highly potential APJ inhibitors for the effective treatment of multiple life-threatening disease conditions.
The APJ system participates in several major disorders including cancer. A multi-QSAR modeling study on some APJ inhibitors was performed for the first time. Some potential molecules were also designed based on the QSAR study conducted.
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