Critical Factors to Understanding the Electrochemical Performance of All-Solid-State Batteries: Solid Interfaces and Non-Zero Lattice Strain

All-solid-state lithium batteries have been developed to secure safety by substituting a flammable liquid electrolyte with a non-flammable solid electrolyte. However, owing to the nature of solids, interfacial issues between cathode materials and solid electrolytes, including chemical incompatibility, electrochemo-mechanical behavior, and physical contact, pose significant challenges for commercialization. Herein, critical factors for understanding the performance of all-solid-state batteries in terms of solid interfaces and non-zero lattice strains are identified through a strategic approach. The initial battery capacity can be increased via surface coating and electrode-fabrication methods; however, the increased lattice strain causes significant stress to the solid interface, which degrades the battery cycle life. However, this seesaw effect can be alleviated using a more compacted electrode microstructure between the solid electrolyte and oxide cathode materials. The compact solid interfaces contribute to low charge-transfer resistance and a homogeneous reaction between particles, thereby leading to improved electrochemical performance. These findings demonstrate, for the first time, a correlation between the uniformity of the electrode microstructure and electrochemical performance through the investigation of the reaction homogeneity among particles. Additionally, this study furthers the understanding of the relationship between electrochemical performance, non-zero lattice strain, and solid interfaces.     

疫情下高职“计算机信息技术”课程的教学探讨

新冠疫情的突如其来改变了人们很多原先的生活节奏,学校里的师生同样面临此困境。文章以高职教学中的基础课“计算机信息技术”为例,指出了线上教学时所面临的一些问题,并给出了一些解决的方法,论述了笔者在线上教学中所实施的教学步骤,力争做到线上线下教学效果的同质等效。     

Ordered mesoporous aluminosilicates with very low Si/Al ratio and stable tetrahedral aluminum sites for catalysis

New and ordered 2D-hexagonal (p6mm) mesoporous aluminosilicates (CMI-11) have been synthesized in strongly alkaline media using aluminosilicate ester ((Bu^sO)₂-Al-O-Si-(OEt)₃) as single-source molecular precursor and CTMABr as surfactant and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption–desorption and ²⁷Al and ²⁹Si MAS NMR spectroscopy. These mesoproous aluminosilicates exhibit a very low Si/Al ratio of 1.9 and highly thermal stable tetrahedral aluminum sites in the mesoporous walls. ²⁷Al and ²⁹Si MAS NMR spectroscopy indicates that the pore walls of CMI-11 are fully condensed with molecular homogeneity of Si–O–Al linkage. These materials are highly important in catalysis, in particular for the petroleum processing and the bulky molecules treatment.     

Polyacrylic acid,a highly efficient dispersant for aqueous processing of tantalum carbide

Polyacrylic acid (PAA) with three different molecular weights (PAA-3000, PAA-15000, PAA-100000) was used as a dispersant to investigate the aqueous dispersion behavior of commercially available TaC powder. TaC stabilized with PAA-3000 polymer showed the best dispersion behavior according to zeta potential and rheological measurements. In addition, the TaC slurry in the presence of PAA-3000 had a minimized average particle size of merely 1.08 µm when dispersed in alkaline aqueous solutions. This was effective to break down any original agglomerates. A characteristic carboxylic peak was detected after adding PAA-3000 to the aqueous TaC system, using XPS analysis. Our TEM results confirmed that the surface properties of TaC were modified by the PAA-3000 dispersant. The slip-cast green body exhibits enhanced homogeneity compared to its dry-pressed counterpart. A dense TaC monolithic ceramic (>99%) was obtained after sintering. This study contributes to the understanding of advanced wet-forming techniques for TaC ceramics.     

苯氧乙醇标准物质的纯度分析方法及不确定度评定

采用质谱(MS)和核磁共振谱(NMR)对原料苯氧乙醇进行定性分析,优化并建立了液相色谱法及气相色谱法测定苯氧乙醇,纯度为99.3％.以甲醇为基体溶液,采用重量-容量法制备苯氧乙醇标准物质.以液相色谱(紫外法、示差法)两种方法进行定值,并做了均匀性检验和稳定性跟踪.建立不确定度评定方法,标准物质特性值为99.3(±1.1) μg/mL(k=2).苯氧乙醇标准物质具有溯源性和准确性,对于化妆品中防腐剂苯氧乙醇含量的准确测定及监控具有重要意义.     

水泥基渗透结晶型防水材料试验方法探讨

主要讨论水泥基渗透结晶型防水材料的试验方法,包括材料本身的匀质性试验、物理力学性能试验、抗渗试验、渗透深度测试的方法。材料性能的测试方法很多,要寻求能反映水泥基渗透结晶型防水材料特点的试验方法,以便为标准的修订提供帮助。     

一种基于结构面密度的岩体结构均质区划分方法

根据结构面发育的主要特点以及工程实际需要，合理选择划分岩体结构均质区的岩体参数是必要的。在某些特殊情况下，选择结构面密度作为划分均质区的依据更为合适。为此，提出了一种基于结构面密度的岩体结构均质区划分方法，即密度分区方法，并通过对西南某大型水电站工程侧裂结构面的密度分区，证明了该方法的可行性。该方法简单、直观、易于操作，有很强的推广实用价值。     

节理岩体表征单元体的分形几何研究

节理岩体的尺寸效应是其内在结构复杂性的体现,应归因于岩体内裂隙网络系统的存在。提出在岩体结构宏观分区的基础上研究表征单元体,应用分形几何的观点进行研究。结果表明,分区内岩体结构具有统计自相似性。进一步的计算表明,用于描述岩体结构特征的分形维数随岩石试样尺寸的增加而减小;但当尺寸增加到某特定值时,分形维数趋于稳定,将此特定值称为结构表征单元体,即尺寸大于结构表征单元体的样本其结构具有代表性。根据表征单元体的定义,尺寸大于表征单元体的岩体试样,其力学性质具有代表性;而结构相似是性质相似的前提,由此可以推知,结构表征单元体为表征单元体取值的下限。     

应用纳米材料提高氧化锌电阻片通流能力

氧化锌电阻片的通流能力主要取决于电阻片的微观均匀性。使用纳米材料,有助于提高瓷体均匀性和致密性,使得氧化锌电阻片电气性能尤其是通流能力得到改善。为使纳米材料充分发挥作用,必须解决纳米材料自身的团聚,并提高料浆混合的均匀性。     

构建成德绵经济圈的区域协调与博弈分析

以构建中的"成德绵"经济圈为对象,运用经济学中"博弈论"的观点和方法分析该区域"整合"的难点所在,对区域协调中的问题提出几点认识,以有效提升区域竞争力,避免城市恶性竞争以及基础设施低水平重复建设。