锂离子电池硅负极循环稳定性研究进展

硅是已知质量比容量最高的锂离子电池负极材料,研究人员希望通过制造可靠的高容量硅负极,生产高能量密度的锂离子电池. 但由于充放电过程中锂在硅材料中嵌入与释放,硅材料发生巨大的体积变化,以致破碎,并从负极上脱落下来. 硅负极容量随着充放循环次数的增加而迅速下降,是其应用进程中受到的最大制约. 本文结合锂离子电池硅负极研究现状,从硅材料本体结构、整体负极结构两方面介绍几种不同的提高硅负极循环稳定性的方法,并对各种方法的稳定性、成本、制备方法等进行比较,提出对未来硅负极材料研究的展望.     

Solvo‐thermal Preparation of One Novel Cadmium(II) Coordination Polymer with 1‐(4‐Aminobenzyl)‐1,2,4‐Triazole and Bi‐functional Photo‐Luminescent Sensing for Acetone and Dichromate

In this work a 1,2,4‐triazole derivative 1‐(4‐aminobenzyl)‐1,2,4‐triazole (abtz) was utilized, one new cadmium(II) coordination polymer, namely [Cd(abtz)I₂]_n ( 1 ) was prepared through the powerful solvo‐thermal synthetic strategy. In compound 1 , the abtz building blocks are interlinked through the central Cd^II ions forming the two‐dimensional (2D) layer coordination framework. Powder X‐ray diffraction (PXRD) characterization also reveals that we have prepared the pure phases of coordination polymer 1 . Optical properties have been determined, which can behave the excellent photo‐luminescent emission of coordination polymer 1 . Photo‐luminescent experiment also reveals that coordination polymer 1 can behave the highly sensitive detection for acetone molecules with high K_sv value (K_sv = 4.12 ×10⁴ L · mol^–1) in the recyclable detection fashion. Additionally, coordination polymer 1 also can behave the highly sensitive detection for pollutant dichromate with excellent quenching efficiency K_sv (K_sv = 2.12 × 10⁴ L · mol^–1) and low detection limit [38 × 10^–3 mM (S/N = 3)]. UV/Vis, photo‐luminescent lifetime, and PXRD patterns also have been determined to analyze the detection mechanism.     

Synthesis,characterization, fluorescence imaging,and cytotoxicity studies of a uracil‐based azo derivative and its metal complexes

A uracil‐based heterocyclic azo derivative was prepared by coupling diazotized 5‐aminouracil with 2‐naphthol. This ligand, viz., 1‐(2,4‐dioxopyrimidine‐5‐yl)‐azo‐naphth‐2‐ol (HNAP), was used as a precursor for the synthesis of a series of complexes with manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) ions. Various physicochemical measurements UV–Visible, Infrared (IR), ¹H NMR, ¹³C Nuclear Magnetic Resonance (NMR), and electron spin resonance (ESR) spectral studies were employed to characterize the ligand and the metal complexes. The ligand showed good selectivity toward Mn²⁺ over the other metal ions with a detection limit of 1.36 μM. This probe was used for the confocal fluorescence imaging of Mn²⁺ ions in Michigan Cancer Foundation‐7 (MCF‐7) cells. The ligand and the metal complexes were tested for their cytotoxicity on the MCF‐7 cell line. It was observed that complexation of HNAP with the metal ions exhibited a promising cytotoxicity.     

Molecular Design Tactics for Highly Efficient Thermally Activated Delayed Fluorescence Emitters for Organic Light Emitting Diodes

Recently, pure organic thermally activated delayed fluorescence (TADF) emitters have attracted considerable interest from the scientific community in the field of organic light emitting diodes (OLEDs) as they can theoretically realize 100 % of the internal quantum efficiency by exploiting both the singlet and triplet excitons via the reverse intersystem crossing enabled by small singlet‐triplet energy splitting. Currently, the external quantum efficiency of the TADF emitters is reaching the level of phosphorescent emitters. Therefore, the TADF approach is considered as a potential alternative to the low efficiency conventional fluorescent and expensive phosphorescent emitters. In this account, we summarized our recent development of blue and green TADF molecular designs to improve the device performances of the TADF devices.     

Using freezing and drying techniques of emulsions for the microencapsulation of fish oil to improve oxidation stability

Epidemiological investigations show that n-3-polyunsaturated fatty acids (PUFA) have a protective effect with respect to coronary heart disease. For a long time fish oil has been known as a source of PUFA. The successful incorporation of fish oil into the normal food components offers an opportunity to increase the intake of PUFA, but fish oil has to be protected against oxidation preferably by microencapsulation. The high temperatures during the traditional spray-drying microencapsulation process lead to an increased oxidation of the PUFA. The authors demonstrate the application of a freeze-drying technique with respect to the production of dried microencapsulated fish oil with high quality and oxidation stability. The influence of emulsion parameters, freezing parameters and formulation on the stability of a dried fish oil emulsion is presented and illustrated. The used procedure gave a product with a good oxidation stability which is available as pellets or powder. It was found that the stability was mainly influenced by the freezing rate and the used encapsulation carbohydrate, whereby the powder showed a better shelf life than the pellets. Concluding, it can be summarized that the production of microencapsulated fish oil by freezing and subsequent freeze-drying offers an opportunity to achieve a product with a good oxidation stability.     

“鱼”乐圈大揭秘

This article introduces the relationship between chemistry and fish farming, fish selling, and fish food. The nitrogen cycle process in fish ponds is introduced to explain the fish farming. "Yufuling" is used as the entry point to fish selling to connect food safety with chemistry. Fishy smell is explained from a chemical perspective for fish food. This paper aims at making a scientific explanation of life phenomena, deepening the consciousness of chemical life, helping people establish a correct view of chemical science, and inspiring youth to learn to use the knowledge that they have learned to explain life phenomena. This paper also tries to show the youth that life cannot be separated from chemistry, and chemistry cannot be separated from life.     

New Opportunities for the Utilization of the Sulfoximine Group in Medicinal Chemistry from the Drug Designer's Perspective**

Extension of the medicinal chemistry toolbox is in the vital interest of drug designers. However, the diffusion of an innovation can be a lengthy process. Along these lines, it took almost 70 years before the use of the sulfoximine group reached a critical mass in medicinal chemistry. Even though interest in this versatile functional group has increased exponentially in recent years, there is ample room for further innovative applications. This Review highlights emerging trends and opportunities for drug designers for the utilization of the sulfoximine group in medicinal chemistry, such as in the construction of complex molecules, proteolysis targeting chimeras (PROTACs), antibody-drug conjugates (ADCs) and novel warheads for covalent inhibition.     

Prebiotically Plausible Autocatalytic Peptide Amyloids

The prebiotic emergence of molecules capable both of self-replication and of storing information was a defining event at the dawn of life. Still, no plausible prebiotic self-replication of biologically relevant molecules has been demonstrated. Building upon the known templating nature of amyloids, we present two systems in which the products of a peptide-bond-forming reaction act as self-replicators to enhance the yield and stereoselectivity of their formation. This first report of an amino acid condensation that can undergo autocatalysis further supports the potential role of amyloids in prebiotic molecular evolution as an environment-responsive and information-coding system capable of self-replication.     

从知识传授到育人:高职“生活中的化学”教学实践*

深挖高职院校公选课“生活中的化学”的育人元素,精心设计教学内容,运用课堂主题辩论、趣味生活实验的设计与展示、探秘生活中的化学等理论知识传授与课内外实践相结合的教学方式,实现全过程育人,充分展现了公选课在立德树人方面的价值。     

再论科学素养培养的关键、路径及意义

基于高中化学教学实践, 探讨、反思学生科学素养培养的关键、路径及意义, 以期为高中化学教学提供参考。认为教师科学素养的提升是学生科学素养培养的关键, 可以通过改变课堂教学模式、形式和内容来落实科学素养培养的目标, 科学素养培养的意义在于让学生成为具有科学理性的人。