Confluence of ZnO and PTFE Binder for Enhancing Performance of Thin-Film Lithium-Ion Batteries

Developing anode materials with high specific capacity and cycling stability is vital for improving thin-film lithium-ion batteries.Thin-film zinc oxide(ZnO)holds promise due to its high specific capacity,but it suffers from volume changes and structural stress during cycling,leading to poor battery performance.In this research,we ingeniously combined polytetrafluoroethylene(PTFE)with ZnO using a radio frequency(RF)magnetron co-sputtering method,ensuring a strong bond in the thin-film composite electrode.PTFE effectively reduced stress on the active material and mitigated volume change effects during Li^(+)ion intercalation and deintercalation.The composite thin films are thoroughly characterized using advanced techniques such as X-ray diffraction,scanning electron microscopy,and X-ray photoelectron spectroscopy for investigating correlations between material properties and electrochemical behaviors.Notably,the ZnO/PTFE thin-film electrode demonstrated an impressive specific capacity of 1305 mAh g^(-1)(=7116 mAh cm^(-3))at a 0.5C rate and a remarkable capacity retention of 82%from the 1st to the 100th cycle,surpassing the bare ZnO thin film(50%).This study provides valuable insights into using binders to stabilize active materials in thin-film batteries,enhancing battery performance.

硼粉含量对Mg/PTFE富燃料推进剂性能的影响

为研究硼粉含量对镁/聚四氟乙烯(Mg/PTFE)富燃料推进剂性能的影响,采用混合模压成型工艺制备了7种不同硼粉含量的Mg/PTFE推进剂药柱。用红外测温仪、TG-DTA、量热仪分别测试其燃烧性能、热分解性能和爆热,并测试了其机械感度。结果表明,加入硼粉后,推进剂的燃烧性能明显改善,硼粉质量分数为15%时,线性燃速和质量燃速达到最高;当硼粉质量分数为20%时,燃烧温度达到最高;随着硼粉含量的增加,爆热稍微降低,完全燃烧热随着硼粉含量的增加而增大;当硼粉质量分数为10%时,高温放热峰温度降低128℃,撞击感度和摩擦感度达到最高值。

飞秒激光对Mg/PTFE药剂烧蚀加工过程安全性分析

文章简要介绍了飞秒激光发展过程及其特点,讨论了利用飞秒激光的超快速时间和超高峰值的特性烧蚀加工烟火药剂Mg/PTFE的可行性与安全性。建立了飞秒激光与Mg/PTFE作用过程中的传热模型,根据模型计算了药剂内部的温度分布以及烧蚀反应放出的热量对周围药剂的影响;在本研究的计算条件下,确定了在切割过程中,受激光作用表面的温度可达3000℃以上,单个激光脉冲的作用深度小于5.0×10-7m,药剂反应放出的热量对周边基本上没有影响,因而飞秒激光能够用于Mg/PTFE药剂的加工。

Mg/PTFE薄膜制备与性能表征

以镁(Mg)为可燃物质,聚四氟乙烯(PTFE)为氧化剂,利用磁控溅射和真空蒸镀两种方法,制备薄膜烟火器件,研究两种制膜工艺在性能上的差异,并对其附着力、薄膜粒度和燃速进行了测量。结果表明,磁控溅射制得的薄膜附着力为35.88mN,粒度为0.1～0.5μm,燃速为(623.9±12.5)mm.s-1,其主要性能优于真空蒸镀法制得的薄膜。

PTFE对Mg与Al_(12)Mg_(17)微爆反应特性的影响

为了探索聚四氟乙烯(PTFE)对镁和Al_(12)Mg_(17)反应特性的影响,采用TG-DSC对样品的高温氧化行为进行测试分析;利用自搭建的高速显微观测系统对其燃烧行为进行了精细地观测;使用XRD和SEM等对反应前后样品的结构和组成等进行了分析;使用光谱仪对样品燃烧过程中的光谱辐射特性进行记录。结果表明,当PTFE在空气中加热时,PTFE分别将Mg和Al_(12)Mg_(17)的起始反应温度提高了283.3℃和368.3℃;Mg与PTFE/Mg样品燃烧过程中,均在490~505nm间观察到了MgO的辐射峰,在517和518nm处观察到了镁的辐射峰;与镁原料相比,PTFE/Mg中观察到了更加明显的微爆燃烧。对于Al_(12)Mg_(17),PTFE的加入有助于其微爆燃烧的发生,样品燃烧过程中在417.486和512nm处观察到的AlO辐射峰说明PTFE的加入可以促进Al_(12)Mg_(17)中铝的燃烧。

一种双靶磁控溅射制备的Mg掺杂的NiO薄膜

采用磁控溅射“共溅射”方法,将Ar气作为溅射气体,高纯NiO和MgO双陶瓷靶作为溅射靶材。当控制NiO和MgO靶的溅射功率分别为190 W和580 W,溅射真空度为2 Pa,衬底温度为300℃时,得到了Mg掺杂的NiO(Ni_(0.61)Mg_(0.39)O)薄膜。该薄膜是一种具有(200)择优取向的晶态薄膜。薄膜表面比较平整,晶粒分布致密,晶粒尺寸约46.9 nm。(200)衍射峰位置相对未掺杂的NiO薄膜向小角度偏移约0.2°。合金薄膜在可见光波段具有较大的透过率,而在300 nm附近透过率陡然下降,其光学带隙向高能方向移动到了3.95 eV。该研究为采用磁控溅射制备高质量的Mg掺杂的NiO薄膜提供了技术支撑。

Effect of Mg-Film Thickness on the Formation of Semiconductor Mg_2Si Films Prepared by Resistive Thermal Evaporation Method

Mg films of various thicknesses were deposited on Si（111） substrates at room temperature by resistive thermal evaporation method, and then the Mg/Si samples were annealed at 40 ℃ for 4 h. The effects of Mg film thickness on the formation and structure of Mg2Si films were investigated. The results showed that the crystallization quality of Mg2Si films was strongly influenced by the thickness of Mg film. The XRD peak intensity of Mg2Si （220） gradually increased initially and then decreased with increasing Mg film thickness. The XRD peak intensity of Mg2Si （220） reached its maximum when the Mg film of 380 um was used. The thickness of the Mg2Si film annealed at 400℃ for 4 h was approximately 3 times of the Mg film.

An overview of progress in Mg-based hydrogen storage films

Mg-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of Mg-based hydrogen storage materials.The present paper reviews the advances in the research of Mg-based hydrogen storage film in recent years, including the advantage of the film, the function theory of fabricating method and its functional theory, and the influencing factors in the technological process. The research status worldwide is introduced in detail. By comparing pure Mg, Pd-caped Mg, nonpalladium capped Mg, and Mg alloy hydrogen storage films, an ideal tendency for producing Mg-based film is pointed out,for example, looking for a cheap metal element to replace the high-priced Pd, compositing Mg film with other hydrogen storage alloy of catalytic elements, and so on.

Comparison on corrosion resistance and surface film of pure Mg and Mg−14Li alloy

To study different corrosion resistances and surface film types of hexagonal close-packed(HCP)pure Mg and body-centered cubic(BCC)Mg−14wt.%Li alloy in 0.1 mol/L NaCl,a series of experiments were conducted,including hydrogen evolution,mass loss,in-situ electrochemical testing combined with Raman spectroscopy and microstructural observation.The results indicate that the corrosion resistance of pure Mg is superior to that of Mg−14Li,and the protective function of the surface films on both magnesium systems is elevated within 16 h of immersion in 0.1 mol/L NaCl.An articulated,thick,and needle-like surface film containing Li2CO3 on Mg−14Li,different from the typically thin,flaky Mg(OH)2 film on pure Mg,is confirmed via scanning electron microscopy(SEM).However,both surface films can be broken down at a high anodic over-potential.Thus,different corrosion resistances of the two Mg systems are ascribed to various protective films forming on their surfaces.

Effects of Mg/PTFE pyrotechnic compositions on reignition characteristics of base bleed propellants and heating mechanism

The effects of magnesium/polytetrafluoroethylene(Mg/PTFE)pyrotechnic compositions on the coupled flow field and reignition mechanism are important aspects governing the perfommance and range of base bleed projectiles(BBPs).Owing to a decrease in pressure and temperature when the BBP leaves the muzzle,rapid depressurization occurs,which extinguishes the base bleed propellant.The Mg/PTFE py-rotechnic composition pressed in the igniter of the base bleed unit(BBU)provides additional energy to the BBU via a chemical reaction.Thus,the extinguished base bleed propellant is reignited under the effect of high-temperature combustion gas jets from the igniter.In this study,a numerical analysis is conducted to evaluate the effects of PTFE and Mg granularity as well as Mg/PTFE pyrotechnic compo-sitions.Owing to the rapid depressurization,the temperature and pressure was found to decrease fordifferent Mg/PIFE pyrotechnic compositions.However,the depressurization time increased as the PTFE granularity increased,the Mg granularity decreased,and the Mg content increased.When the pressure in the combustion chamber of the BBU decreased to the atmospheric pressure,the combustion gas jets from the igniter expand upstream(rather than downstream).However,these combustion gas jets exhibit different axial and radial expansion characteristics depending on the pyrotechnic compositions used,The results show that the reignition delay time,ta,of the base bleed propellant was 377.608,94.27,387.243,523.966,and 221.094 ms for cases A-E,respectively.Therefore,it was concluded that the Mg/PTFE pyrotechnic composition of case B was the most beneficial for the reignition of the base bleed propellant,with the earliest addition of energy and mass to the BBP.

Effect of solution concentration on sealing treatment of Mg-Al hydrotalcite film on AZ91D Mg alloy

Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy,and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance.Scanning electron microscope(SEM)and X-ray diffraction(XRD)measurements were carried out to analyze the surface morphology and phase composition.The corrosion resistance of Mg-Al hydrotalcite film after sealing treatment was evaluated by the polarization curve and electrochemical impedance spectroscopy(EIS)tests.The results showed that lower concentration of Ce-containing solution was beneficial to seal the micro-cracks on Mg-Al hydrotalcite film,and improve the surface integrity and corrosion resistance;higher concentration of Ce-containing solution could seal fewer micro-cracks,and the corrosion resistance was decreased owing to the disintegration of Mg-Al hydrotalcite film.

Formation mechanism of pulse current anodized film on AZ91D Mg alloy

The kinetics of forming process of pulse current anodized film on AZ91D Mg alloy was studied by the voltage-time and thickness-time curves.The surface morphology,structure,elemental constitution and valences of the anodic films were analyzed by SEM,EDS,XPS and XRD respectively.The results show that the film-forming process can be divided into four stages.Formation of a dense layer before sparking is the first stage.Formation of a porous layer accompanied with slight sparking is the second stage.The third stage is characterized by fast growth of the porous layer accompanied with more intensive sparking.The fourth stage starts after the sparking process becomes even more vigorous and the pores become large.

Preparation of Mg-Yb alloy film by electrolysis in the molten LiCl-KCl-YbCl_3 system at low temperature

The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such as cyclic voltammetry,chronopotentiometry and chronoamperometry were used in order to explore the deposition mechanism of Yb.The reduction process of Yb3+ is stepwise reactions which are single-electron and double-electron reversible charge transfer reactions.The speed control step was a diffu...

Improved electrochemical hydrogen storage properties of Mg-Y thin films as a function of substrate temperature

Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to 1725 mAh·g-1.Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.

Nucleation and growth behavior of coating film on Mg–Al–Zn alloy with different surface topographies via plasma electrolytic oxidation

This work was made to investigate how nucleation and growth behavior of the coating film were affected by surface topographies of Mg–Al–Zn alloy substrate during the initial stage of plasma electrolytic oxidation(PEO).To satisfy this end,a single substrate was prepared by mechanical treatment exhibiting rough and smooth regions with an equal area on the surface.The rough region with prominent hills and grooves induced the breakdown of passive film,which was indicated by an early appearance of plasma discharge on the rough region since nucleation of coating film occurred preferentially around the hills.However,the coating film grown on the grooves was somewhat thicker and more porous than the film grown on the hills and smooth regions.This was due to the fact that the growth of the coating film was found to be localized in the presence of rough region,which was in line with the discharge activities.Herein,the nucleation and growth behavior during the initial stage of PEO will be discussed schematically on the basis of microstructural interpretation.

Structure and micro-tribological properties of PTFE/Al_2O_3 micro-assembling film

In order to improve the wear resistance of elastic metallic-plastic thrust bearing pad, micro-assembling PTFE/Al2O3 multi-layer film was developed by alternating radio frequency（RF） magnetron sputtering PTFE and Al2O3 targets. For enhancing the adhesion of the interfaces between PTFE and Al2O3 film, N+ implantation was employed. The structure, mechanical and micro-tribological properties were studied by XPS, X-ray photoelectron spectrometer and atomic force and friction force microscope （AFM/FFM）. The results show that the multi-layer consists of Al2O3 component and crystalline PTFE. The hardness of the multi-layer modified by ion implantation is less than that of Al2O3,but its toughness is greatly improved. The friction coefficient of PTFE/ Al2O3 multi-layer modified by ion implantation is much lower than that of Al2O3 film, and its resistance to wear is much greater than that of PTFE film. Therefore the wear resistance of elastic metallic-plastic thrust bearing pad is greatly improved.

Si_(3)N_(4)/PTFE复合材料转移膜形貌与磨损率定量分析

聚四氟乙烯(PTFE)基复合材料摩擦转移膜对其摩擦学性能有着决定性影响,转移膜形貌与磨损率定量关系对PTFE基复合材料的摩擦学性能优化有重要意义。文章对Si_(3)N_(4)/PTFE复合材料转移膜膜厚与覆盖率进行定量表征并建立两者与磨损率的函数关系。结果表明:转移膜最大厚度和覆盖率均与复合材料磨损率之间有较高的拟合度,最大厚度与覆盖率在转移膜不同形貌时对复合材料磨损率的影响起不同作用;转移膜最大厚度大于0.319μm时,其最大厚度的增加对提高复合材料磨损变化起主导作用;转移膜最大厚度小于0.319μm时,覆盖率的增加对降低复合材料的磨损起主导作用。

Hydrogen storage properties of preferentially orientated Mg-Ni multilayer film prepared by magnetron sputtering

Mg-Ni multi-layer thin film was deposited on (001) Si wafer by magnetron sputtering with dual-target. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis reveal that the microstructure of the Mg-Ni multilayer thin film is composed of fine-crystalline Ni layer and crystalline [001] Mg layer. Hydrogenation process of the films were carried out by using the automatic gas reaction controller. The films undergone hydrogenation for different time were analyzed by XRD. The results show that hydrogenation properties of Mg with different preferential orientations are different. (002) diffraction peak of Mg disappears in compensating the appearing of the peaks of Mg2NiH4 and MgH2 in hydrogenation at 533 K, while the (101) peak still remains. The result reveals that the Mg film with (001) preferential orientation absorbs hydrogen at certain temperature easier than that of the Mg film with (101) orientation. This phenomenon can be explained in the view point of the energy change for the nucleation and growth of hydride in different crystal plane.

Mg-Ni THIN FILM-A POTENTIAL NEGATIVE ELECTRODE FOR NIKEL-METAL HYDRIDE BATTERY

Mg-Ni thin films for nickel-metal hydride (Ni-MH) battery negative electrode were prepared on three different substrates by using magnetron sputtering with compacted Ni and Mg mixture powder. The microstructure of Mg-Ni thin films deposited on the glass and the Ni foil substrate respectively was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Mg-Ni thin films were in amorphous structure and the composition of the thin film was homogeneous. Electrochemical measurement show the discharge capacity of the thin film negative electrode deposited on the foam Ni substrate was 284.8mAh/g in 6M alkaline electrolyte and the internal resistance was much lower than that of the electrode prepared by the ball-milled powder during the charge-discharge cycle.

The transverse laser induced thermoelectric voltages in step flow growth (1-x)Pb(Mg_(1/3)Nb_(2/3))O_(3-x)PbTiO_3 thin films

This paper reports that the transverse laser induced thermoelectric voltages （LITV） axe observed for the first time in the step flow growth （1- x）PD（Mg1/3Nb2/3）O3-xPbTiO3 （PMN-PT, x = 0.20, 0.33, 0.50） thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate （PMN） and lead titanate （PT）, there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength, the largest induced voltage is observed in the 0.50Pb（Mg1/3Nb2/3）O3-0.50 PbTiO3 films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.