High mechanical strength Si anode synthesis with interlayer bonded expanded graphite structure for lithium-ion batteries

Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical use.The root of these challenges lies in the mechanical instability of the material,which subsequently leads to the structural failure of the electrode.Here,we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles.This composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering method.Notably,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,resulting in an impressive areal capacity of 2.9 mA h cm^(-2)(736 mA h g^(-1)) and a steady cycle life(93% after 100cycles).Such outsta nding performance is paired with features appropriate for large-scale industrial production of silicon batteries,such as active mass loading of at least 3.9 mg cm^(-2),a high-tap density electrode material of 1.68 g cm^(-3)(secondary clusters:1.12 g cm^(-3)),and a production yield of up to 1 kg per day.

Microstructure,strength and welding window of aluminum alloy-stainless steel explosive cladding with different interlayers

Aluminum 5052(Al 5052)-stainless steel 316(SS 316)plates were explosively cladded with Al 1100,pure copper and SS 304 interlayers.The operational parameters viz.,standoff distance,explosive mass ratio(mass ratio of the explosive to the flyer plate)and inclination angle were varied and the results were presented.The advent of interlayer relocates the lower boundary of the welding window,and enhances the welding regime by 40%.A triaxial welding window,considering the influence of the third operational parameter,was developed as well.Use of interlayer transforms the continuous molten layer formed in the traditional Al 5052-SS 316 explosive clad interfaces into a smooth interface devoid or with a slender presence of intermetallic compounds.The microhardness,ram tensile and shear strengths of the interlayered clads are higher than those of the traditional explosive clads,and the maximum values are witnessed for stainless steel interlaced Al 5052-SS 316 explosive clads.

Temperature-dependent interlayer exchange coupling strength in synthetic antiferromagnetic [Pt/Co]_2/Ru/[Co/Pt]_4 multilayers

In this work, we experimentally investigated the thermal stability of the interlayer exchange coupling field(Hex) and strength(-Jiec) in synthetic antiferromagnetic(SAF) structure of [Pt(0.6)/Co(0.6)]2/Ru(tRu)/[Co(0.6)/Pt(0.6)]4multilayers with perpendicular anisotropy. Depending on the thickness of the spacing ruthenium(Ru) layer, the observed interlayer exchange coupling can be either ferromagnetic or antiferromagnetic. The Hexwere studied by measuring the magnetization hysteresis loops in the temperature range from 100 K to 700 K as well as the theoretical calculation of the-Jiec. It is found that the interlayer coupling in the multilayers is very sensitive to the thickness of Ru and temperature. The Hexexhibits either a linear or a non-linear dependence on the temperature for different thickness of Ru. Furthermore, our SAF multilayers show a high thermal stability even up to 600 K(Hex= 3.19 kOe,-Jiec= 1.97 erg/cm~2 for tRu=0.6 nm, the unit 1 Oe = 79.5775 A·m-1), which was higher than the previous studies.

Effect of Metallurgical Behaviour at the Interface between Ceramic and Interlayer on the Si_3N_4/1.25Cr-0.5Mo Steel Joint Strength

By using newly developed CuNi5~25Ti16~28 B rapldly solidifled brazing filler the joining of Si3 N4/1.25Cr-0.5Mo steel has been carried out with interlayer method. If employing the interlayer structure of steel (0.2 mm)/W (2.0 mm)/Ni(0.2 mm), the joint strength can be increased greatly compared with employing that of Ni/W/Ni, and the three point bend strength of the Joint shows the value of 261 MPa. The metallurgical behaviour at the interface between Si3N4 and the interlayer has been studied. It is found that Fe participated in the interfacial reactions between Si3N4 and the brazing filler at the Si3N4/steel (0.2 mm) interface and the compound Fe5Si3 was produced. However, since the reactions of Fe with the active Ti are weaker than those of Ni with Ti, the normal inter facial reactions were still assured at the interface of Si3N4/steel (0.2 mm) instead of Si3N4/Ni (0.2 mm), resulting in the improvement of the joint strength. The mechanism of the formation of Fe5Si3 is also discussed. Finally, some ideas to further ameliorate and simplify the interlayer structure are put forward.

胶粘剂用量对CR/玻纤布复合胶布粘接性能的影响

针对氯丁橡胶(CR)和玻纤布压延成的薄层复合胶布,研究了玻纤布涂覆胶粘剂的用量对复合胶布层间粘合强度和拉伸剪切强度的影响。结果表明,随着玻纤布上胶量的逐渐增多,复合胶布的层间粘合强度和拉伸剪切强度先提高后降低,当胶粘剂用量为20%时,达到峰值;SEM照片显示,不同上胶量复合胶布的破坏界面呈现出明显的差异,阐明了胶布的层间粘合强度和拉伸剪切强度所呈变化趋势的原因;玻纤布、CR及复合胶布层间粘合破坏界面的的红外谱图与SEM照片吻合,进一步证明了复合胶布的层间粘合强度和拉伸剪切强度变化的趋势。

冲击力下薄壁内衬复合管界面黏结强度效应分析

【目的】研究薄壁内衬复合管在受冲击力作用下的界面黏结强度对层间剥离屈曲的影响。【方法】建立薄壁内衬复合管在弹性阶段的非线性分析模型,对薄壁内衬复合管材模态试验与分析模型的分析结果进行对比,验证有限元分析模型可靠性。通过改变衬层与原基层管壁间的界面黏结强度,研究复合管在冲击力下的动态特征。【结果】研究结果表明,当冲击荷载较小、管道变形处于弹性阶段时,薄壁内衬复合管的损伤大都集中在层间界面处。界面黏结强度对层间剥离屈曲有较大的影响,随着层间界面黏结强度的增加,外基层管与内衬层的最大等效应力差值减少。此外,外基层管和内衬层的变形协调性能力随着黏结强度增加而增大,径向层间位移减小,增加了复合管的整体性和连续性。【结论】研究结果可为薄壁内衬修复管道设计方法及层间界面效应分析提供参考。

连接温度对W/Ni/Kovar真空扩散连接接头界面结构及结合强度的影响

以Ni箔为中间层材料,采用真空扩散连接方法进行W与Kovar合金的连接,研究了连接温度对W/Ni/Kovar接头界面结构和剪切强度的影响。结果表明:在520~1000℃范围内,利用真空扩散连接工艺均可成功制备出W/Ni/Kovar接头样品。随着连接温度的升高,Kovar/Ni界面与Ni/W界面的扩散层厚度逐渐增加,而接头剪切强度呈先上升后下降的趋势。当连接温度为800℃时,样品的接头剪切强度高达182 MPa,此时主要发生W块体的剪切断裂。

顺层深路堑边坡滑带土强度特性和基底预留厚度预警分析

含软弱夹层的顺层深路堑边坡在边坡工程中普遍存在,滑带土强度和基底预留厚度(开挖边坡基底到软弱夹层的距离)是影响其稳定性的2个关键性因素。以杨宣(杨柳-宣城)高速K42路堑边坡为例,分析了边坡变形演化过程和基底隆起变形特征,通过适合研究大剪切位移下土体抗剪强度的环剪试验揭示了边坡深部滑带土的特性,应用滑带土的饱和残余强度参数进行了边坡开挖基底预留厚度分析。结果表明:K42滑带土有明显的应变软化特性,且法向应力越小滑带土应变软化特性表现越明显;由峰值抗剪强度到残余抗剪强度,黏聚力和内摩擦角均表现出衰减效应,且黏聚力衰减程度大于内摩擦角;滑带土残余抗剪强度参数中的残余黏聚力随剪切速率的变化很小,而残余内摩擦角和剪切速率呈对数函数φ=0.1303ln v+7.3197关系变化,当剪切速率<2 mm/min时,滑带土残余抗剪强度参数对剪切速率较为敏感,反之敏感性较差;最后,依据边坡不同临界状态的回归方程h_(1)、h_(2)、h_(3)将不同坡率下的基底预留厚度分成A(失稳)、B(欠稳定)、C(基本稳定)以及D(稳定)4个区,并且在此基础上建立了基底预留厚度判据和边坡开挖基底预留厚度预警模型。

VCrAl_(1.21)Ni_(0.93)Co_(1.85)高熵合金中间层真空扩散连接TC4钛合金和T2铜

根据伪二元合金设计策略和共晶高熵合金设计理念,设计并制备了VCrAl_(1.21)Ni_(0.93)Co_(1.85)共晶高熵合金中间层用于真空扩散连接TC4钛合金和T2铜,研究了不同连接温度对TC4/T2扩散连接接头微观组织和力学性能的影响规律.结果表明,所有接头界面结合良好无缺陷产生,在TC4侧的连接界面附近发生了部分相变,由α-Ti向β-Ti进行转变,并且形成了部分魏氏体组织.Ti_(2)(Co,Ni),Ti_(2)(V,Cr,Al),Ti(V,Cr,Co)和(V,Cr)(Al,Ni,Co)相形成在TC4/VCrAl_(1.21)Ni_(0.93)Co_(1.85)界面上,而VCrAl_(1.21)Ni_(0.93)Co_(1.85)/T2界面上形成了(V,Cr)(Al,Ni,Co)和(V,Cr)(Cu,Ni,Co)_(3)相.界面上形成高熵微观组织结构起到高熵固溶强化作用,扩散层Ⅰ和Ⅱ对应的生长激活能分别为229 kJ/mol和191 kJ/mol,接头抗剪强度在880℃时达到最大为194 MPa,接头主要沿着BCC基体相和B2相交替位置断裂,断口表面出现河流花样特征,属于一种典型的解理断裂模式.

干湿循环下炭质泥岩软弱夹层剪切强度及渗透性演化规律研究

针对云南某露天矿边坡中的炭质泥岩软弱夹层,开展了室内干湿循环加速模拟试验、直接剪切试验和变水头渗透试验,研究了干湿循环作用下炭质泥岩软弱夹层抗剪强度和渗透性的演化规律,分析了循环次数对抗剪强度和渗透系数的影响,结果表明:干湿循环对炭质泥岩软弱夹层的抗剪强度影响显著,不同竖向荷载下,抗剪强度劣化趋势基本相同;随着干湿循环次数的增加,其内摩擦角基本不变,但黏聚力显著减小,且在干湿循环1次时黏聚力减幅最大,2~7次时黏聚力劣化速率较快,在干湿循环超过7次时,炭质泥岩软弱夹层的黏聚力变化速率趋于平缓,最终拟合得出黏聚力与干湿循环次数之间的指数函数关系模型;炭质泥岩软弱夹层的渗透系数和干湿循环次数呈正相关,循环次数在0~4次时渗透系数变化较为平缓,4次之后渗透系数显著增大,在7次循环时达到最大值,之后渗透系数基本不变。研究结果可为类似矿山边坡软弱夹层的强度和渗透系数预测提供参考。

气体辅助对PLA/TPU/GF复合材料3D打印性能的影响

熔融沉积成型(FDM)是一种应用比较广泛的快速成型工艺,但生产出的热塑性产品存在力学性能差的问题。将气体辅助挤出与FDM技术相结合,利用高温高压气体对打印件表层进行瞬间加热促进层间黏结,从而提高制件的机械强度。制备了热塑性聚氨酯(TPU)和玻璃纤维(GF)共混改性聚乳酸(PLA)3D打印材料,对比了PLA改性前后流变性能的变化。分别研究了不同气体辅助参数,如气体温度、气体流量及气体压力对FDM制件拉伸性能和冲击性能影响。结果表明:GF和TPU改性的PLA相对于纯PLA非牛顿性更强,流变性能有所提升,有助于3D打印成型。在气体辅助条件下,FDM 3D打印成型的制件强度较无气体辅助时均有所提升,最高可提升116.1%。不同气体参数对FDM制件力学性能影响规律不同,其中气体流量对制件性能影响最大。综合考虑,当气体温度、体积流量及压力分别为250℃、0.8 L/min、0.4 MPa时,制件成型性能最佳。

一种不粘轮乳化沥青的制备方法及其性能研究

在高温环境下,乳化沥青粘层会粘附在施工车辆的轮胎上,进而导致沥青路面层间粘结失效。为了解决这一问题,通过不同的基质沥青进行混合来制备不粘轮乳化沥青,对其进行了一系列性能测试,包括恩格拉粘度、储存稳定性以及蒸发残留物的软化点等指标。同时,通过黏附率试验来检验不粘轮乳化沥青的粘轮性能,与市场上销售的普通乳化沥青粘层油相比,在高温环境下,不粘轮乳化沥青有着显著的不粘轮效应。通过对两种乳化沥青的层间粘结力进行了研究,并分析了不同环境温度下对乳化沥青粘结力的影响水平。研究结果显示,无论在是室温还是高温环境下,不粘轮乳化沥青的层间剪切强度均优于市售普通乳化沥青,并且在高温环境下,不粘轮乳化沥青的层间粘结作用能够得到更好的发挥。不粘轮乳化沥青的各项指标符合规范要求,它可以减少施工时间,延长道路使用寿命,降低维修频次,降低工程造价的目标。

东欧某高速公路复理石边坡牵引式滑坡处治分析

基于东欧某高速公路复理石边坡牵引式工程滑坡,建立30~50 cm厚软弱夹层模拟滑带土的有限元模型,采用强度折减法对滑坡分步施工支护进行稳定性分析,并与传统极限平衡法进行对比。结果表明:强度折减法可根据坡体塑性区分布初步判定滑面位置,结合地质勘察及位移监测确定最终滑面位置;强度折减法滑带土层反分析法确定的滑面抗剪强度参数略高于极限平衡法;同等滑带土参数下,强度折减法施工工况稳定系数略低于极限平衡法,运营及地震工况稳定系数与极限平衡法相当。

Mechanical Properties of Methane Hydrate-Bearing Interlayered Sediments

The complex distribution of gas hydrate in sediments makes understanding the mechanical properties of hydrate-bearing sediments a challenging task.The mechanical behaviors of hydrate-bearing interlayered sediments are still poorly known.A series of triaxial shearing tests were conducted to investigate the strength parameters and deformation properties of methane hydrate-bearing interlayered sediments at the effective pressure of 1 MPa.The results indicate that the stress-strain curves of hydrate-bearing interlayered sediments are significantly different from that of hydrate-bearing sediments.The peak strength,Young's modulus,initial yielding modulus,and failure mode are deeply affected by the methane hydrate distribution.The failure behaviors and mechanism of strain softening and hardening patterns of the interlayered specimens are more complicated than those of the integrated specimens.This study compares the different mechanical behaviors between integrated and interlayered specimens containing gas hydrate,which can serve as a reference for the prediction and analysis of the deformation behaviors of natural gas hydrate reservoirs.

软弱层间岩层空区积水疏放孔防塌技术研究

针对在工作面疏放上覆采空区积水的过程中,受到煤层间软弱覆岩的影响,钻孔极易塌孔、缩径,堵塞疏水通道,导致采空区积水疏放效率低乃至无法疏放问题,以磁窑沟煤矿13103工作面为研究对象,基于筛管强度理论,研制了一种疏放水钻孔防塌孔护管,对护管在软弱层间岩层采空区积水疏放工程中的应用展开研究。结果表明:煤层间软弱砂岩的完整性差和采空区顶板岩层的失稳破碎,是导致钻孔产生塌孔、缩径的根本原因;护管采用钢制管体、螺纹连接,管壁设有疏水孔和倒索,通过筛孔护管强度校核及筛孔参数优选,确定疏水孔直径16 mm、密度28孔/m及相位角30°;通过在软岩孔段中安装钢制筛管可以有效解决塌孔问题,应用护管后的钻孔出水量衰减明显减缓,单孔最大疏放水速率提升58.3%。

Microstructure and mechanical properties of Mg-to-Al dissimilar welded joints with an Ag interlayer using ultrasonic spot welding

Lightweight ZEK100-0 Mg alloy and A16022-T43 Al alloy with an Ag interlayer were joined via ultrasonic spot welding(USW),focusing on the microstructural change and tensile lap shear strength of the welded joints in relation to welding energy.Mg/Al interface was superseded by Mg/Ag and Al/Ag interfaces,and unfavorable Mg门A-intermetallic compound was eliminated.Ag foil was observed to be intact in the nugget center,while it was broken or dissolved at the nugget edge at high welding energy levels.The diffusion layer at the Mg/Ag interface consisted of two distinctive sub-layers:Mg3Ag intermetallic compound adjoining Ag foil,and Mg3Ag-l-Mg eutectic structure adjacent to Mg.Only a thin diffusion layer consisting mainly of Ag3Al occurred al lhe Al/Ag interface.The tensile lap shear strength first increased,reached its peak value,and then decreased with increasing welding energy.The shear strength achieved in the present study was〜31%higher than that of the joint without interlayer.Interfacial failure occurred at all energy levels,with Ag foil particles or fragments being stuck on both Mg and Al sides due to its intense interaction with Mg and Al via accelerated diffusion during USW.The results obtained pave the way for the challenging dissimilar welding between Mg and Al alloys.

Friction welding of AA6061 to AISI 4340 using silver interlayer

The present work pertains to the study on joining of AA6061 and AISI 4340 through continuous drive friction welding. The welds were evaluated by metallographic examination, X-ray diffraction, electron probe microanalysis, tensile test and microhardness. The study reveals that the presence of an intermetallic compound layer at the bonded interface exhibits poor tensile strength and elongation. Mg in AA6061 near to the interface is found to be favourable for the formation and growth of Fe2Al5 intermetallics. Introduction of silver as an interlayer through electroplating on AISI 4340 resulted in accumulation of Si at weld interface, replacing Mg at AA6061 side, thereby reducing the width of intermetallic compound layer and correspondingly increasing the tensile strength. Presence of silver at the interface results in partial replacement of Fe-Al based intermetallic compounds with Ag-Al based compounds. The presence of these intermetallics was confirmed by X-ray diffraction technique. Since Ag-Al phases are ductile in nature, tensile strength is not deteriorated and the silicon segregation at weld interface on AA6061 in the joints with silver interlayer acts as diffusion barrier for Fe and further avoids formation of Fe-Al based intermetallics. A maximum tensile strength of 240 MPa along with 4.9% elongation was obtained for the silver interlayer dissimilar metal welds. The observed trends in tensile properties and hardness were explained in relation to the microstructure.

Interfacial structure and mechanical property of Mg/Al alloy joint diffusion bonded with Zn interlayer metal

The characteristics of microstructure and mechanical strength of the Mg/Al alloy joint diffusion bonded with a Zn interlayer were studied by means of metalloscopy,X-ray diffraction(XRD),electron probe microanalysis(EPMA) and mechanical property test.Investigations showed that the Mg/Al alloy joint diffusion bonded with Zn interlayer consists of a multilayer sandwich structure,including the transition zone on Al side,Zn and Zn-Mg transition zone,as well as the transition zone on Mg side.The transition zone on Al side is very thin and composed mainly of a solid solution structure,while the Zn-Mg transition zone has a relative larger dimension after a rapid eutectic reaction.The addition of zinc interlayer inhibits the inter-diffusion of Mg and Al alloy efficiently.The Zn-Mg transition zone constitutes the main part of the joint and consists of Mg crystals and the new phase formed is MgZn intermetallic compound.The mechanical strength of Mg/Al alloy joints diffusion bonded with Zn interlayer reached 42 MPa.According to the phase constitution analyses executed on each side of the fracture face,it was deduced that the fracture of Mg/Al alloy joint located around the interface of Zn and Zn-Mg transition zone.

Effect of interlayer on the mechanical properties of YG8 hard carbide/40Cr steel brazed joints

The effects of Cu foil and Ni foil on the mechanical properties of YG8 hard carbide/4OCr steel brazed joints were investigated. The results show that both Cu foil and Ni foil were beneficial to decrease the residual stress and enhance the joint strength. Moreover, Ni foil exhibited the better impact on enhancing the joint strength relative to Cu foil. When Cu foil was used as interlayer material, the key factor to restrain the joint strength was the massive and quick dissolution of Cu. Therefore, in order to prevent the excessive dissolution of Cu foil, the process parameter should be controlled strictly in the brazing process.

Mechanical properties and microscopic failure process of exemplary argillaceous interlayer from east China

The landslide disaster caused by the argillaceous interlayer not only destroys buildings,cultivated land,and roads but also seriously endangers human life and safety.This study concerns the mineral composition of selected argillaceous interlayer and their strength characteristics.To study the mineral composition of argillaceous interlayers,8 kinds of samples in the southern Jiangsu region of China were analyzed utilizing X-ray diffraction(XRD).The repeated direct shear strength tests(RDST)were carried out on the undisturbed specimens of the argillaceous interlayer.The results show that the argillaceous interlayer with high content of kaolinite shows ductile failure mode,which means that there is no obvious residual strength in the shear process.The arrangement of mineral particles on the shear surface of the specimens after different shear displacements was observed under the scanning electron microscope(SEM).It was observed that mineral particles on the shear surface showed a more directional arrangement with the increase of shear displacement.Furthermore,the influence of shear direction on the argillaceous interlayer with completely oriented mineral particles was studied through numerical experiments with four shear strength mechanisms proposition proposed.The influence of the mineral arrangement on the action occasion and magnitude of dilatancy component of shear strength is clarified in the shear mechanism.