不可燃氟代碳酸酯基钠离子电池电解液

Lithium-ion batteries (LIBs) are widely used in cellphones, laptops, and electric cars owing to their high energy density and long operational lifetime. However, their further deployment in large-scale energy storage systems is restricted by the uneven distribution of lithium resources (~0.0017% (mass fraction, w) in the Earth's crust). Therefore, alternative energy storage systems composed of abundant elements are of urgent need. Recently, sodium-ion batteries (SIBs) have attracted significant attention and are considered to be a potential alternative for next-generation batteries owing to abundant sodium resources (~2.64% (w) of the Earth's crust), suitable potential (−2.71 V), and low cost. SIBs are similar to LIBs in terms of their physical and electrochemical properties. Previous studies have mainly focused on SIB storage materials, including hard carbon, alloys, and hexacyanoferrate, while the safety of SIBs remains largely unexplored. Similar to LIBs, the current electrolytes used in SIBs are mainly composed of flammable organic carbonate solvents (or ether solvents), sodium salts, and functional additives, which pose possible safety issues. Moreover, the chemical activity of sodium is much higher than that of lithium, leading to a higher risk of fire, thermal runaway, and explosion. To overcome this problem, herein we propose a fluorinated non-flammable electrolyte composed of 0.9 mol∙L⁻¹ NaPF₆ (sodium hexafluorophosphate) in an intermixture of di-(2, 2, 2 trifluoroethyl) carbonate (TFEC) and fluoroethylene carbonate (FEC) in a 7 : 3 ratio by volume. Its physical and electrochemical properties were studied by ionic conductivity, direct ignition, cyclic voltammetry, and charge/discharge measurements, demonstrating excellent flame-retarding ability and outstanding compatibility with sodium electrodes. The electrochemical tests showed that the Prussian blue cathode retained a capacity of 84 mAh∙g⁻¹ over 50 cycles in the prepared electrolyte, in contrast to the rapid capacity degradation in a flammable conventional carbonate electrolyte (74 mAh∙g⁻¹ with 57% capacity retention after 50 cycles). To test the practical application of the proposed electrolyte, a hard carbon anode was used and exhibited exceptional performance in this system. The enhancement mechanism was further verified by Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning emission microscopy (SEM) investigations. Polycarbonate on the surface of the cathode played an important role for the studied electrolyte system. The polycarbonate may originate from FEC decomposition, which can enhance the ionic conductivity of the solid electrolyte interface (SEI) layer and reduce impedance. Hence, we believe that this proposed electrolyte may provide new opportunities for the design of robust and safe SIBs for next-generation applications.     

钴催化双齿导向基辅助的1-萘胺衍生物与醇的区域选择性碳氢键烷氧基化反应

研究了吡啶酰胺双齿导向的钴催化1-萘胺衍生物的区域选择性碳氢键烷氧基化反应.研究发现不仅一元醇可以作为烷氧化剂在标准条件下较好地实现1-萘胺C(8)位的烷氧化反应,而且具有多重用途的脂肪二元醇以及低聚乙二醇,也可以以中等的收率得到相应的目标化合物,这可能是钴催化碳氢键活化构筑碳氧键的首次发现.此外,利用这个实验方法,以氘代甲醇为烷氧化试剂实现了同位素标记的8-烷氧基取代的1-萘胺衍生物的合成.通过控制实验,发现该反应中吡啶酰基是最佳的双导向基团,而且反应过程可能经历了单电子转移机理.     

The Crystallization and Melting Behaviors of PDLA-b-PBS-b-PDLA Tri-block Copolymers

In this study,the poly(D-lactide)-block-poly(butylene succinate)-block-poly(D-lactide)(PDLA-b-PBS-b-PDLA)triblock copolymers with a fixed length of PBS and various lengths of PDLA are synthesized,and the crystallization behaviors of the PDLA and PBS blocks are investigated.Although both the crystallization behaviors of PBS and PDLA blocks depend on composition,they exhibit different variations.For the PDLA block,its crystallization behaviors are mainly influenced by temperature and block length.The crystallization signals of PDLA block appear in the B-D 2-2 specimen,and these signals get enhanced with PDLA block length.The crystallization rates tend to decrease with increasing PDLA block lendth during crystallizing at 90 and 100°C.Crystallizing at higher temperature,the crystallization rates increase at first and then decrease with block length.The crystallization rates decrease as elevating the crystallization temperature.The melting temperatures of PDLA blocks increase with block lengths and crystallization temperatures.For the PBS block,its crystallization behaviors are mainly controlled by the nucleation and confinement from PDLA block.The crystallization and melting enthalpies as well as the crystallization and melting temperatures of PBS block reduce as a longer PDLA block has been copolymerized,while the crystallization rates of the PBS block exhibit unique component dependence,and the highest rate is observed in the B-D 2-2 specimen.The Avrami exponent of PBS crystallites is reduced as a longer PDLA block is incorporated or the sample is crystallized at higher temperature.This investigation provides a convenient route to tune the crystallization behavior of PBS and PLA.     

Organic Ligand‐Free Hydroformylation with Rh Particles as Catalyst†

Summary of main observation and conclusion An efficient and organic ligand-free heterogeneous catalytic system for hydroformylation of olefins is highly desirable for both academy and industry.In this study,simple Rh black was employed as a heterogeneous catalyst for hydroformylation of olefins in the absence of organic ligand.The Rh black catalyst showed good catalytic activity for a broad substrate scope including the aliphatic and aromatic olefins,affording the desired aldehydes in good yields.Taking the hydroformylation of ethylene as an example,86%yield of propanal and TOF of 200 h-1 were obtained,which was superior to the reported homogeneous catalytic systems.In addition,the catalyst could be reused five times without loss of activity under identical reaction conditions,and the Rh leaching was negligible after each cycle.     

Modification of Hole Transport Layers for Fabricating High Performance Non‐fullerene Polymer Solar Cells

Interfacial engineering is expected to be a feasible strategy to improve the charge transport properties of the hole transport layer (HTL), which is of crucial importance to boost the device performance of organic solar cells (OSCs). In this study, two types of alcohol soluble materials, 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F₄‐TCNQ) and di‐tetrabutylammoniumcis–bis(isothiocyanato)bis (2,2’‐bipyridyl‐4,4’‐dicarboxylato) ruthenium(II) (N719) dye were selected as the dopant for HTL. The doping of F₄‐TCNQ and N719 dye in poly (ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with and without integrating a graphene quantum‐dots (G‐QDs) layer has been explored in poly[[2,6′‐4‐8‐di(5‐ethylhexylthienyl)benzo[1,2‐b:3,3‐b]dithiophene][3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thio‐phenediyl:(2,2′‐((2Z,2′Z)‐(((4,4,9, 9‐tetrakis(4‐hexylphenyl)‐4,9‐dihydro‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene‐2,7‐diyl)bis(4‐((2‐ethylhexyl)oxy)thiophene‐5,2‐diyl))bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile (PTB7‐Th:IEICO‐4F) OSCs. The power conversion efficiency of the non‐fullerene OSCs has been increased to 10.12% from 8.84%. The influence of HTL modification on the nano‐morphological structures and photophysical properties is analyzed based on the comparative studies performed on the control and modified devices. The use of chemical doping and bilayer strategy optimizes the energy level alignment, nanomorphology, hole mobility, and work‐function of HTL, leading to considerable reduction of the leakage current and recombination losses. Our work demonstrates that the doping of HTL and the incorporation of G‐QDs layer to constitute a bilayer HTL is an promising strategy to fabricate high performance non‐fullerene polymer solar cells     

由醚氧桥联羧酸配体构筑的铜(Ⅱ)、锌(Ⅱ)和锰(Ⅱ)配位聚合物的合成、晶体结构、荧光及光催化性质

采用水热方法,用醚氧桥联的三羧酸配体（H₃dpna）和四羧酸配体（H₄deta）为主配体,2,2''-联吡啶（2,2''-bipy）和菲咯啉（phen）为辅助配体,分别与CuCl₂·H₂O、ZnCl₂和MnCl₂·4H₂O反应,合成了2个二维配位聚合物{[Cu₃（μ₄-dpna）₂（2,2''-bipy）₂]·4H₂O}_n（1）和{[Zn₃（μ₄-dpna）₂（2,2''-bipy）₂（H₂O）₂]·6H₂O}_n（2）以及2个一维配位聚合物{[M₂（μ₄-deta）（phen）₂（H₂O）]·3H₂O}_n（M=Mn（3）,Zn（4））,并对其结构、荧光和光催化性质进行了研究。结构分析结果表明配合物1和2属于单斜晶系,P2₁/c和C2/c空间群。由于采用了不同的金属离子,配合物1和2呈现不同的二维层结构。配合物3和4为异质同心结构,均属于单斜晶系,P2₁/n空间群。配合物3和4都具有一维链结构。另外,研究了这些配合物的荧光和对有机染料亚甲基蓝的光催化降解性能,结果表明配合物2和4可以高效地降解亚甲基蓝。     

Expedient Synthesis of Ketones via N‐Heterocyclic Carbene/Nickel‐Catalyzed Redox‐Economical Coupling of Alcohols and Alkynes†

An N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives as well as stoichiometric byproducts. These reactions convert both benzylic and aliphatic alcohols and alkynes, two basic feedstock chemicals, into various α‐branched ketones in a single chemical step.     

Strong and Superhydrophobic Wood with Aligned Cellulose Nanofibers as a Waterproof Structural Material†

Lightweight structural materials are important for the energy efficiency of applications, particularly those in the building sector. Here, inspired by nature, we developed a strong, superhydrophobic, yet lightweight material by simple in situ growth of nano‐SiO₂ and subsequent densification of the wood substrate. In situ generation of SiO₂ nanoparticles both inside the wood channels and on the wood surfaces gives the material superhydrophobicity, with static and dynamic contact angles of 159.4^o and 3^o, respectively. Densification of the wood to remove most of the spaces among the lumen and cell walls results in a laminated, dense structure, with aligned cellulose nanofibers, which in turn contributes to a high mechanical strength up to 384.2 MPa (7‐times higher than natural wood). Such treatment enables the strong and superhydrophobic wood (SH‐Wood) to be stable and have excellent water, acid, and alkaline resistance. The high mechanical strength of SH‐Wood combined with its excellent structural stability in harsh environments, as well its low density, positions the strong and superhydrophobic wood as a promising candidate for strong, lightweight, and durable structural materials that could potentially replace steel.     

Synthesis of core-shell structured Au@Bi2S3 nanorod and its application as DNA immobilization matrix for electrochemical biosensor construction

The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.     

Construction of diaminobenzoquinone imines via ferrocene-initiated radical reaction of benzoquinone with amines

A ferrocene-initiated radical reaction of benzoquinone with amines has been successfully developed for the direct access to diaminobenzoquinone imines in high yields,in which the comme rcially available and cheap ferrocene was employed as a radical initiator and TBHP was used as an oxidant.Moreover,this reaction could be achieved with low loading of ferrocene(0.5 mol%).This protocol is highly efficient with good substrate tolera nce and provides a new approach for the construction of benzoquinone imines with potential pharmaceutical interest.