Stabilizing Solid-state Lithium Metal Batteries through In Situ Generated Janus-heterarchical LiF-rich SEI in Ionic Liquid Confined 3D MOF/Polymer Membranes

Pursuing high power density lithium metal battery with high safety is essential for developing next-generation energy-storage devices, but uncontrollable electrolyte degradation and the consequence formed unstable solid-electrolyte interface (SEI) make the task really challenging. Herein, an ionic liquid (IL) confined MOF/Polymer 3D-porous membrane was constructed for boosting in situ electrochemical transformations of Janus-heterarchical LiF/Li₃N-rich SEI films on the nanofibers. Such a 3D-Janus SEI-incorporated into the separator offers fast Li⁺ transport routes, showing superior room-temperature ionic conductivity of 8.17×10⁻⁴ S cm⁻¹ and Li⁺ transfer number of 0.82. The cryo-TEM was employed to visually monitor the in situ formed LiF and Li₃N nanocrystals in SEI and the deposition of Li dendrites, which is greatly benefit to the theoretical simulation and kinetic analysis of the structural evolution during the battery charge and discharge process. In particular, this membrane with high thermal stability and mechanical strength used in solid-state Li||LiFePO₄ and Li||NCM-811 full cells and even in pouch cells showed enhanced rate-performance and ultra-long life spans.     

火焰原子吸收光谱法测定地质样品中的砷

微量砷的测定方法主要是原子荧光光谱法;含砷量较高的样品测定,一般采用容量法和分光光度法,但这两种方法相对来说流程长,过程繁琐。实验对样品中中等含量砷的测定进行了研究,样品经酸溶后,在硝酸(1%)介质中,用火焰原子吸收光谱法在波长193.7nm处测其吸光度,结果表明吸光度与其质量浓度在0~100μg/mL呈线性关系。方法的测定相对标准偏差(RSD)为0.8%,检出限为10.5μg/g,实验操作简便,适合样品中较高含量砷的分析测定。     

硫化锌与硫化锌/氧化锌异质结纳米线的化学气相沉积法制备与表征

介绍一种利用石墨还原快速制备大量硫化锌纳米线的方法,并分别合成了超晶格型、双轴型、核/壳型的硫化锌/氧化锌异质结纳米线。所合成的硫化锌纳米线存在六方纤锌矿和立方闪锌矿两种晶型,纳米线长度达几十微米,直径在20-50 nm,直径均匀且产量很高。在具有双轴型的硫化锌/氧化锌异质结中,首次发现具有超结构特征的氧化锌。HRTEM分析表明,硫化锌/氧化锌超晶格异质结界面为ZB-ZnS(111)∥ZnO(0001),而核/壳型异质结界面为W-ZnS(0001)∥ZnO(0001),这三个晶面分别为各自晶体的极性面,即所合成的硫化锌/氧化锌异质结中极性面相互平行。对ZnS 和ZnS/ZnO 异质结的生长机制进行了探讨,并对硫化锌纳米线与硫化锌/氧化锌异质结的光学性质进行了分析。     

超声成像实验仪

我们模拟了一个原理相对容易、结构相对简单的超声成像实验。通过超声波测试仪发射和接收换能器信号 ,输出的电压信号送入计算机的A/D卡。A/D卡的另一通道采集换能器的跃变位置信息 ,并将数据提供给成像程序 ,把物体某一断层的截面图画出。通过这一实验 ,我们可以了解超声波在固 /液两相流中的传播原理 ,同时也可掌握数据采集和一般的成像方法     

探究铁和铝在浓硫酸和浓硝酸中的电化学行为

铁和铝在冷的浓硫酸和浓硝酸中都因被钝化而阻止其进一步被腐蚀,通过用Fe、Al做原电池的电极材料,考察其在浓硫酸、浓硝酸中的钝化情况：Fe、Al的钝化快慢、钝化后金属表面氧化膜的致密程度、酸液温度等对钝化的影响等均有所不同。     

Hexaniobate nanotubes with variable interlayer spacings

The novel hexaniobate nanotubes with variable interlayer spacings have been prepared via intercalating–exfoliating–rolling mechanism at the room temperature. The hexaniobate nanotubes are single crystalline with multiple walls. A few single-wall nanotubes have been observed also. The interlayer spacings of 0.83, 1.9, 2.2, 2.3, 2.4, 2.5, 2.8, 3.3 and 3.6 nm are, respectively, obtained by the intercalation of a series of primary alkylamines. The formation mechanism is discussed in detail and this method is applicable to other layered structure materials. These hexaniobate nanotubes are inorganic/organic composite and therefore represent a new class of tubular materials.     

Hierarchical ZnO microrods: synthesis,structure, optical and photocatalytic properties

Hierarchical ZnO microrods have been prepared by cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal process at low temperature. Sheetlike or fluffy ZnO nanostructures have been developed in a large density on the surface of the microrods. The ZnO cores grow preferentially along [001]; the nanosheets are single crystalline and grow in two dimensions along the [001] and [120] directions. The formation of hierarchical structures has been attributed to the presence of CTAB in the solution, which facilitates the secondary nucleation and growth. The nanosheet-covered hierarchical microrods have been analyzed by Raman and photoluminescence spectroscopy, and they exhibit a blue emission at 465 nm and a strong orange emission at 640 nm. Photocatalytic activities of the products have been examined, and the nanosheet-covered hierarchical microrods display the best activity in photodegradation of phenol due to their unique surface features and high surface area.     

Thermal stability of flexible polyurethane foams containing modified layered double hydroxides and zinc borate

Abstract

Flexible polyurethane foams (FPUFs) have been modified to contain layered double hydroxides (LDHs) by dihydrogen phosphate (H₂PO₄ ^?). The thermal stability of the prepared foams has been characterized using thermogravimetric analysis (TGA) at 5, 10, 20, 30, and 40?°C/min heating rates. The experimental data indicate that the temperature range for the two pyrolysis stages of FPUF is about 212–350?°C and 350–565?°C, respectively. Integral programmed decomposition temperature (IPDT) has been calculated according to the measured data, which was found that the IPDT of the modified FPUF was increased to 526?°C. Additionally, the thermal stability of FPUF composite has been also evaluated by the activation energy (E) on the basis of the pyrolysis kinetics of FPUF composites during thermal decomposition using Coats–Redfern integral method. These results manifest that the presence of intercalated LDHs enhances the thermal stability of FPUF.     

瞬态抑制二极管电磁脉冲响应建模

针对目前浪涌保护器件性能分析方法不完善、缺乏准确数学模型的问题,提出了一种基于NARX神经网络的电磁脉冲响应时域建模方法,并给出NARX神经网络建模的理论基础及设计步骤。通过组建传输线脉冲测试平台及静电放电实验平台,对NUP2105L型瞬态抑制二极管进行注入实验,采集输入输出实验数据并建立NARX神经网络模型。对建模效果进行分析,所建模型可以较为准确地预测输入脉冲为方波脉冲、人体金属模型及机器模型静电放电电磁脉冲时,响应电压曲线趋势、响应时间、脉冲峰值、箝位时间及箝位电压等性能指标,验证了模型的正确性。