Recent Progress and Perspectives of Sodium Metal Anodes for Rechargeable Batteries

Sodium metal anodes have attracted significant attention due to their high specific capacity,low redox potential and abundant resources.However,the dendrites and unstable solid electrolyte interphase(SEI)of sodium anodes restrict the development of sodium metal batteries.This review includes the recent progress on the Na anode protection in sodium metal batteries.The strategies are summarized as modified three-dimensional current collectors,artificial solid electrolyte interphases,and electrolyte modifications.Conclusions and perspectives are envisaged for the further understanding and development of Na metal anodes.     

Thermodynamic insights into n-alkanes phase change materials for thermal energy storage

n-Alkanes have been widely used as phase change materials (PCMs) for thermal energy storage applications because of their exceptional phase transition performance, high chemical stability, long term cyclic stability and non-toxicity. However, the thermodynamic properties, especially heat capacity, of n-alkanes have rarely been comprehensively investigated in a wide temperature range, which would be insufficient for design and utilization of n-alkanes-based thermal energy storage techniques. In this study, the thermal properties of n-alkanes (C₁₈H₃₈-C₂₂H₄₆), such as thermal stability, thermal conductivity, phase transition temperature and enthalpy were systematically studied by different thermal analysis and calorimetry methods, and compared with previous results. Thermodynamic property of these n-alkanes was studied in a wide temperature range from 1.9 K to 370 K using a combined relaxation (Physical Property Measurement System, PPMS), differential scanning and adiabatic calorimetry method, and the corresponding thermodynamic functions, such as entropy and enthalpy, were calculated based on the heat capacity curve fitting. Most importantly, the heat capacities and related thermodynamic functions of n-heneicosane and n-docosane were reported for the first time in this work, as far as we know. This research work would provide accurate and reliable thermodynamic properties for further study of n-alkanes-based PCMs for thermal energy storage applications.     

稀世之宝—铂*

铂是一种化学性质极其稳定的贵金属,铂、铂合金以及铂配合物在催化剂、医药、传感器等领域具有重要应用。简要介绍铂的发现史、自然分布与资源现状、铂的应用等3个方面,其中铂的应用,重点从铂基催化剂、铂合金纳米材料、发光铂配合物、铂类抗癌药物等4个方面展开介绍。     

高中化学必修课程“变化观念与平衡思想”学科核心素养的系统构成研究

“变化观念与平衡思想”学科核心素养的系统构成对开展“素养导向”的教学与评价具有重要意义。通过课标分析,基于学科能力模型明确了高中必修学段“变化观念与平衡思想”核心素养的核心知识与活动经验、认识方式、研究对象及问题情境、学科能力活动及其表现等4个维度的具体内涵,系统建构了高中化学必修课程“变化观念与平衡思想”学科核心素养模型。     

用高效疏水色谱法对多种脲变α-淀粉酶折叠中间体的研究

用高效疏水色谱法对用脲变性的α-淀粉酶的体外折叠中间体进行了分离，发现脲变α-淀粉酶折叠至少有19个中间体，而且，这些中间体在色谱流出液中可稳定一周．这一结论已由电泳、离子交换色谱和体积排阻色谱法证实．此外，还用紫外吸收光谱和荧光发射光谱研究了这些折叠中间体与天然α-淀粉酶构象之间的差异．     

1,4-双-(二硫代羧基)哌嗪乙基聚合物的合成及其吸附性能

固相合成;1;4-双-(二硫代羧基)哌嗪乙基聚合物的合成及其吸附性能     

A Diruthenium‐Based Mixed Spin Complex Ru25+(S=1/2)‐CN‐Ru25+(S=3/2)

An unusual tetra‐nuclear linear cyanido‐bridged complex [Ru₂(μ‐ap)₄‐CN‐Ru₂(μ‐ap)₄](BPh₄) ( 1 ) (ap=2‐anilinopyridinate) has been synthesized and well characterized. The crystallographic data, magnetic measurement, IR, EPR and theoretical calculation results demonstrate that complex 1 is the first example of mixed spin Ru₂⁵⁺‐based complex with uncommon electronic configurations of S=1/2 for the cyanido‐C bound Ru₂⁵⁺ and S=3/2 for the cyanido‐N bound Ru₂⁵⁺. This phenomenon can be understood by the theoretical calculation results that from the precursor Ru₂(μ‐ap)₄(CN) (S=3/2) to complex 1 the energy gap between π* and δ* orbitals of the cyanido‐C bound Ru₂⁵⁺ core increases from 0.57 to 1.61 eV due to the enhancement of asymmetrical π back‐bonding effect, but that of the cyanido‐N bound Ru₂⁵⁺ core is essential identical (0.56 eV). Besides, the analysis of UV/Vis‐NIR spectra suggests that there exists metal to metal charge transfer (MMCT) from the cyanido‐N bound Ru₂⁵⁺ (S=3/2) to the cyanido‐C bound Ru₂⁵⁺ (S=1/2), supported by the TDDFT calculations.     

Electrochemical Monitoring of ROS/RNS Homeostasis Within Individual Phagolysosomes Inside Single Macrophages

The existence of a homeostatic mechanism regulating reactive oxygen/nitrogen species (ROS/RNS) amounts inside phagolysosomes has been invoked to account for the efficiency of this process but could not be unambiguously documented. Now, intracellular electrochemical analysis with platinized nanowire electrodes (Pt‐NWEs) allowed monitoring ROS/RNS effluxes with sub‐millisecond resolution from individual phagolysosomes impacting onto the electrode inserted inside a living macrophage. This shows for the first time that the consumption of ROS/RNS by their oxidation at the nanoelectrode surface stimulates the production of significant ROS/RNS amounts inside phagolysosomes. These results establish the existence of the long‐postulated ROS/RNS homeostasis and allows its kinetics and efficiency to be quantified. ROS/RNS concentrations may then be maintained at sufficiently high levels for sustaining proper pathogen digestion rates without endangering the macrophage internal structures.     

原位氧化还原沉淀水热合成法制备LixMn2O4尖晶石

Li xMn2O4尖晶石是新一代的锂离子二次电池正极材料 [1], 其合成方法对材料的电化学性质影响很大[2].常规合成大多采用高温固相反应法, 此法具有反应温度高, 反应时间长, 容易产生缺陷和产物不纯净等缺点, 导致所合成的锂离子二次电池正极材料的性能较差. 目前用水热合成法制备电池正极材料Li xMn2O4尖晶石尚未见文献报道. 本文在常规水热合成法的基础上采用原位氧化还原沉淀水热合成法 [3]制备前驱物, 该法合成条件更温和, 而且使材料的综合性能得到了改善和提高. 