Tracking the phase transformation and microstructural evolution of Sn anode using operando synchrotron X-ray energy-dispersive diffraction and X-ray tomography

Tin(Sn)holds great promise as an anode material for next-generation lithium(Li)ion batteries but suffers from massive volume change and poor cycling performance.To clarify the dynamic chemical and microstructural evolution of Sn anode during lithiation and delithiation,synchrotron X-ray energydispersive diffraction and X-ray tomography are simultaneously employed during Li/Sn cell operation.The intermediate Li-Sn alloy phases during de/lithiation are identified,and their dynamic phase transformation is unraveled which is further correlated with the volume variation of the Sn at particle-and electrode-level.Moreover,we find that the Sn particle expansion/shrinkage induced particle displacement is anisotropic:the displacement perpendicular to the electrode surface(z-axis)is more pronounced compared to the directions(x-and y-axis)along the electrode surface.This anisotropic particle displacement leads to an anisotropic volume variation at the electrode level and eventually generates a net electrode expansion towards the separator after cycling,which could be one of the root causes of mechanical detachment and delamination of electrodes during long-term operation.The unraveled chemical evolution of Li-Sn and deep insights into the microstructural evolution of Sn anode provided here could guide future design and engineering of Sn and other alloy anodes for high energy density Li-and Na-ion batteries.

Fast synchrotron X-ray tomography study of the packing structures of rods with different aspect ratios

We present a fast synchrotron X-ray tomography study of the packing structures of rods with different aspect ratios. Utilizing the high flux of the X-rays generated from the third-generation synchrotron source, we can complete a high- resolution tomography scan within a short period of time, after which the three-dimensional （3D） packing structure can be obtained for the subsequent structural analysis. The image phase-retrieval procedure has been implemented to enhance the image contrast. We systematically investigated the effects of particle shape and aspect ratio on the structural properties including packing density and contact number. It turns out that large aspect ratio rod packings will have wider distributions of free volume fraction and larger mean contact numbers.

Dealloying-induced dual-scale nanoporous indium-antimony anode for sodium/potassium ion batteries

InSb alloy is a promising candidate for sodium/potassium ion batteries(SIBs/PIBs)but challenged with achieving high performance by dramatic volumetric changes.Herein,nanoporous(np)-InSb with dualscale phases(cubic/hexagonal(C/H)-InSb)was fabricated by chemical dealloying of ternary Mg-In-Sb precursor.Operando X-ray diffraction(XRD)and ex-situ characterizations well rationalize the dealloying/alloying mechanisms and the formation of dual-scale microstructures/phases.As an anode for SIB/PIBs,the np-InSb electrode exhibits superior reversible capacities and lifespan compared with the monometallic porous(p)-In electrode,stemming from the dealloying-induced dual-scale nanoporous architecture and alloying strategy with proper composition.The operando XRD results demonstrate that the(de)sodiated mechanism of the np-InSb electrode involves a two-step(de)alloying process,while the(de)potassiated mechanism is associated with a full electrochemically-driven amorphization upon cycling.Additionally,the gas evolution during the(dis)charge process was monitored by on-line mass spectrometry.

Reaction mechanism and additional lithium storage of mesoporous MnO_(2) anode in Li batteries

Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phenomenon are unclear.For the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode material.Herein,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1<X<2)→MnO→Mn metal,followed by a reversible reaction between Mn metal and Mn3O4.Furthermore,soft X-ray absorption spectroscopy results indicate that additional reversible formation-decomposition of the electrolyte-derived surface layer occurs and contributes to the reversible capacity of MnO2 after the first discharge.These findings contribute to further understanding of the reaction mechanism and additional lithium storage of MnO2 and suggest practical strategies for developing high energy density anode materials for next-generation Li batteries.

管子-管板角焊缝无损检测研究

管子-管板角焊缝检测传统的方式是采用PT检测。PT的检测方法有其自身的缺点,只能检测表面开口的缺陷,置于焊缝中埋藏的缺陷,这种检测方法就不再奏效。在设备运用的故障中泄露是常见的现象之一,这给生产及生命安全带来危险。保证管子-管板角焊缝的质量就显得尤为重要。本文介绍管子-管板角焊内部缺陷无损检测的另一种方法:采用X射线棒阳向后透照的方式对管子-管板进行射线照相。

铝电解阳极导杆组钢爪头半自动电渣焊机的研发与应用

阳极导杆组是铝电解槽阳极的金属结构件,在铝电解槽生产过程中,阳极导杆组会因为导杆缺陷、焊接缺陷、钢爪头缺陷、外观几何尺寸、表面质量等质量因素下线,下线后的导杆组经维修合格后进入下一个循环周期。钢爪头的修复是导杆修理过程中的重要环节,原有修复工艺是将报废的钢爪头切割,锯切新钢爪头,对结合面开坡口并打磨,再组对焊接。这种工艺生成的焊缝压降较大,焊接质量难以保证。钢爪头半自动熔铸技术,成功的解决了阳极钢爪头焊接的难题,有效的提高了焊接质量,降低了焊缝压降,提高了劳动效率,降低了维修成本。

Effect of Anodization on the Graphitization of PAN-based Carbon Fibers of PAN-based Carbon Fibers

One-step pretreatment,anodization,is used to activate the polyacrylonitrile （PAN）-based carbon fibers instead of the routine two-step pretreatment,sensitization with SnCl2 and activation with PdCl2.The effect of the anodization pretreatment on the graphitization of PAN-based carbon fibers is investigated as a function of Ni-P catalyst.The PAN-based carbon fibers are anodized in H3PO4 electrolyte resulting in the formation of active sites,which thereby facilitates the following electroless Ni-P coating.Carbon fibers in the presence and absence of Ni-P coatings are heat treated and the structural changes are characterized by X-ray diffraction and Raman spectroscopy,both of which indicate that the graphitization of PAN-based carbon fibers are accelerated by both the anodization treatment and the catalysts Ni-P.Using the anodized carbon fibers,the routine two-step pretreatment,sensitization and activation,is not needed.

Sodiophilic and conductive carbon cloth guides sodium dendrite-free Na metal electrodeposition

Sodium metal battery(SMB)technology is one of the most promising candidates for next-generation rechargeable energy storage systems due to its high theoretical capacity and economical costeffectiveness.Unfortunately,its practical implementation is hindered by several challenges including short life-span and fast capacity decay,which is closely related to the uncontrollable generation of the sodium dendrites.Herein,a nitrogen and oxygen co-doped three-dimensional carbon cloth with hollow tubular fiber units was constructed as the host material for Na plating(Na@CC)to tackle these challenges.The obtained composite electrode can effectively reduce the nucleation overpotential of Na,guide the homogeneous Na^(+)flux,increase the kinetics of Na electrodeposition,lower the effective current density and eventually suppress the formation of electrochemically inactive Na dendrites.As a result,batteries built with the Na@CC composites exhibited stable long-term cycling stability.To gain an in-depth and comprehensive understanding of such phenomena,non-destructive and three-dimensional synchrotron X-ray tomography was employed to investigate the cycled batteries.Moreover,the COMSOL Multiphysics simulation was further employed to reveal the Na electrodeposition mechanisms.The current work not only showcases the feasibility of currently proposed sodiophilic 3 D Na@CC composite electrode but also provides fundamental insights into the underlying working mechanisms that govern its outstanding electrochemical performance.

XPS Analysis of the Cerium Conversion Coating on the Anodized A16061/SiC_p

A method of concentration analysis based on X-ray photoelectron spectroscopy (XPS) results was introduced. The concentration of Ce-rich conversion coating on the anodized Al based metal matrix composites AI6061/SiCp was then studied according to this method. The results revealed that the Ce conversion coating on the anodized AI6061/SiCp consisted of Al oxide, Ce oxide and Ce hydroxide. The state of Ce element exhibited the mixture of Ce3+ and Ce4+. Some of Cell I was oxidized to be CelV in the outer layer coating.

Surface Modification of Titanium Plate with Anodic Oxidation and Its Application in Bone Growth

Using implants for dental applications are well-accepted procedures as one of the solutions for periodontal defect repair. Suitable design and materials, their reaction with the surrounding hard tissues and interfacial biomechanical properties are still considered to be the primary criteria which need to be addressed. The purpose of present study was to evaluate the bone repair around pure titanium implants and porous surface using anodic oxidation technique, after their insertion in tibiae of rats (n = 15). Five animals received pure titanium-surface implants in tibia, 5 rough-surface implants (TiO2/Ti) in tibia and last five acted as control group. The interfacial integrity and compositional variation along the interface were studied using scanning electron microscope (SEM) with energy dispersive analysis of X-ray (EDX) and histopathology after 2 months. The rats were sacrificed 8 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological analyses to evaluate new bone formation at the implant-bone interface as well as the tibiae were radio graphed. The SEM-EDX results confirmed the initial stability for the Ti implant, but the regeneration of new bone formation was faster in the case of TiO2/Ti implant, and hence could be used for faster healing. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area with surface roughness at implant-bone interface can help into the formation of physico-chemical bondage with the surrounding hard tissues.

Manufacturing Nano Electrode is Sensitive to Light for Produce Hydrogen Fuel

This research is aimed at preparing nano （WO3：Sn） thin film, so that manufacturing anode electrode for a cell electrolysis to produce hydrogen fuel, this thin film was prepared on glass substrates by using deposition laser pulse （LPD） technique have been studying optical properties through the spectra of absorbance and transmittance, was determine the optical energy gap was observed that the permeability increases with the wavelength found that these films have high transmittance in the visible spectral region. The allowed direct band gap was found to increase from （2.9 eV） structured characteristics was studied through the analysis of X-ray diffraction （XRD） of the prepared film for determining the yielding phase which are to set the with standard tables. Also, the sample was tested atomic force microscope to identify the roughness of prepared films surface, and has been the study of the volume of gas output voltages with change, time and current.

一维棒状FeMo_(2)S_(4)的合成及储锂性能研究

【目的】合理设计和调控电极材料的微观结构是显著提升其电化学性能的基础。【方法】采用溶剂热-煅烧法,合成了具有一维棒状结构的FeMo_(2)S_(4),并将其用作锂离子电池的负极材料。【结果】研究发现,相比于无规则块体电极结构,FeMo_(2)S_(4)的一维棒状结构减少了离子/电子的传输距离,提高了反应动力学。此外,较大的比表面积提供了大量的电化学活性位点,进而提高储锂容量。电化学测试结果表明,FeMo_(2)S_(4)电极具有高比容量(在0.5 A/g的电流密度下,初始放电比容量和充电比容量分别为1201和976.2 mAh/g),具备良好的倍率性能和循环稳定性。【结论】该研究可为后续过渡金属硫化物负极材料的结构设计及调控提供借鉴和指导。

碳还原法制备棒状硅基材料及其在锂浆料电池中的应用

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为结构导向剂,正硅酸乙酯(TEOS)为硅源,柠檬酸为碳源,采用水热法得到凝胶状二氧化硅/碳前驱体,采用旋转蒸发方式去除溶剂,通过高温热处理,得到棒状硅氧基碳负极活性材料,提高浆料体系无紧密束缚环境下硅碳材料的性能。借助X射线衍射(XRD)仪、无机元素分析(EA)仪、比表面积及孔隙度分析仪和扫描电子显微镜(SEM)对棒状硅基材料进行结构和形貌表征。结果表明,合成的棒状硅基材料首尾相连,形成莲藕链束,长度约为1~3μm,直径约为200 nm,孔径为6.9 nm,比表面积为282 m^(2)/g。与管长>5μm,比表面积900 m^(2)/g,直径1~2 nm的单壁碳纳米管导电剂在电解液体系中形成长程、短程互补的多级网络,加上大量介孔的存在,有利于保持浆料悬浮稳定性。用世伟洛克电池进行电化学性能测试,电化学测试结果表明首次放电比容量为1300 mAh/g,充电比容量为726 mAh/g,首效为55.8%,在0.05 C下,循环50次充电比容量从726 mAh/g变为557 mAh/g,比容量保持率为76.7%。本工作在用P123为结构导向剂制备二氧化硅的过程中,引入碳源,得到同时具有碳包覆和碳还原二氧化硅的硅基材料,避免使用镁热还原二氧化硅,再碳包覆带来的复杂工艺流程。

阳极导杆组全流程自动化修复解决方案

阳极导杆组件是电解铝生产的重要组成部分之一。目前阳极导杆组件基本由人工修复,这种方式存在人员劳动强度大、修复效率低、质量不稳定等问题,导致阳极导杆组件在生产阶段易发生脱落、开裂或寿命降低等情况。本文介绍了一种阳极导杆组全流程自动化修复解决方案。该方案涵盖了窄间隙全截面焊接工艺及装备、基于电阻热压力焊的阳极钢爪修复技术及装备、铝导杆修复全流程自动化技术及装备。应用该方案每日修复组件数量可达40组以上,使用寿命延长一半以上,同时降低作业人员的劳动强度,并使电解铝行业吨铝节电15 kW·h以上。

家用储热水箱牺牲阳极寿命的分析研究

本文基于水质电阻率、牺牲镁阳极棒发生电流的计算公式,推导出采用镁棒质量、镁棒直径、电位差、水质TDS(溶解性总固体)、水温等5个易获得的参数进行镁棒寿命的快速计算公式,分析得出水质TDS、水温、镁棒结构对镁棒使用寿命的影响关系。以具体示例计算得出水质TDS、水温、镁棒直径对镁棒使用寿命的影响数值,并给出在极限使用条件下,可以采用加配分压电阻和增加镁棒配重的方式提升镁棒使用寿命,确保镁棒使用寿命满足基本维保时间要求。

Amorphous germanium-crystalline bismuth films as a promising anode for magnesium-ion batteries

Magnesium-ion batteries(MIBs)are promising alternatives to lithium-ion batteries due to their safety and high theoretical specific capacity,and the abundance of magnesium reserves.However,their anodes and electro-lytes severely restrict the development of MIBs,so alloy-type anodes provide an effective strategy to circum-vent the surface passivation issue encountered with Mg metal in conventional electrolytes.Theoretically,a germanium anode can deliver a high specific capacity of 1476 mAh g?1,but hitherto,no experimental reports have described Ge in MIBs.Herein,we experimentally verified that Ge could reversibly react with Mg 2þions through the design of dual-phase Ge–Bi film electrodes fabricated by magnetron co-sputtering.Notably,a Ge 57 Bi 43 electrode delivered a high specific capacity of 847.5 mAh g?1,owing to the joint alloying reactions of Ge and Bi with Mg,which was much higher than the specific capacity of Bi(around 385 mAh g?1).Moreover,the Ge–Bi anode showed excellent rate performance,good cycling stability,and superior compatibility with conventional electrolytes such as Mg(TFSI)2.More importantly,the Mg storage mechanism of the Ge–Bi anode was unveiled by operando X-ray diffraction,and density functional theory calculations rationalized that the introduction of Bi to form Ge–Bi evidently decreased the defect formation energy and effectively boosted the electrochemical reactivity of Ge with Mg.

不同标记线制备方法对脊柱连接棒疲劳性能的影响

目的 研究不同标记线制备工艺对脊柱后路内固定系统连接棒疲劳性能和系统压缩疲劳性能的影响。方法 根据YY/T 0119.4—2014标准对脊柱连接棒进行4点弯曲疲劳测试。在一定应力作用下,依据YY/T 0857—2011对激光标记线连接棒和双色彩氧标记线连接棒进行系统压缩疲劳试验。结果 在715 MPa应力下,自制激光标记线连接棒和竞品厂家激光标记线连接棒疲劳寿命较无标记线连接棒分别下降了95%和98%;与未标记连接棒相比,激光标记连接棒疲劳强度由742 MPa下降至342 MPa,降低了54%。双色彩氧连接棒的疲劳寿命和疲劳强度与无标记线连接棒相当。双色彩氧连接棒系统压缩疲劳强度较激光标记连接棒提高约20%。结论 激光制备标记线显著降低了脊柱连接棒的疲劳性能和系统的压缩疲劳强度,改进的双色彩氧工艺制备标记线对连接棒的疲劳性能无影响,能有效降低临床断裂风险,为连接棒的性能改善和工艺开发提供参考。

热水器用AZ31B型镁合金牺牲阳极挤压棒电化学性能测试研究

采用ICP-AES法、电化学性能14 d测试法测定热水器用镁合金牺牲阳极棒中的合金元素含量、开路电位、闭路电位、实际电容量、电流效率等参数,通过金相显微镜、扫描电镜-X射线能谱分析仪表征腐蚀表面结构。结果表明:镁合金牺牲阳极中合金元素Al、Zn、Mn含量分别为2.887%、0.849%、0.669%,开路电位、闭路电位、实际电容量与电流效率分别为-1.6295 V、-1.5375 V、1327.6 A·h/kg、60.4%,分析测试值均符合GB/T17731-2015规范要求;合金晶粒清晰可见,晶界分明,表面腐蚀较为均匀,表明AZ31B型镁合金牺牲阳极材质结构性能较好。

阳极铝导杆组件智能化自动焊接技术开发及应用

针对传统的铝电解槽阳极铝导杆组件人工焊接存在劳动强度大、焊接效率低、焊接质量不稳定等问题,联合开发了阳极铝导杆组件智能化自动焊接技术。通过铝导杆倒角加工工艺技术、智能化自动焊接工艺技术及装备技术优化等有效途径,实现了智能化焊接作业,在300 kA、500 kA用铝导杆阳极铝导杆组件得到成功应用,降低了劳动强度,生产效率提高了(1.5~1.6)倍、合格率提高了6.9%~9.5%。

铝电解槽阳极导杆两种连接方式的比较与分析

介绍了铝电解槽阳极导杆两种连接方式。对于传统爆炸块焊接方法和铝钢自动焊方法进行了工艺对比、所需费用对比、焊接质量对比和焊接效率对比。经过综合比较后,表明铝钢自动焊方法优于传统爆炸块焊接方法。