Zn?In LDHs在Zn?Ni二次电池中的电化学性能

采用水热法制备Zn?In LDHs,并且将其作为锌镍二次电池的新型负极材料。利用扫描电镜（SEM）和X射线衍射仪（XRD）对制备的Zn?In LDHs进行了形态和微观结构的分析。通过循环伏安（CV）、Tafel极化曲线和恒电流充电放电测试研究了Zn?In LDHs作为锌镍电池负极材料的电化学性能。形貌表征发现制备的Zn?In LDHs呈现出六边形片状结构,电化学性能研究结果表明Zn?In LDHs应用到Zn–Ni二次电池中具有很好的循环可逆性能和抗腐蚀性能,恒电流充电放电测试结果分析可知,Zn?In LDHs电极表现出了较为优异的循环稳定性以及充放电特性。经过100次循环后,循环保持率可以达到92.25%。      

粒度对锂离子电池用中间相炭微球电化学性能的影响

采用电化学测试手段,对锂离子电池用负极材料中间相炭微球的粒径分布对其电化学性能的影响进行了深入研究.结果表明,中间相炭微球的粒径对其大电流性能和循环寿命有着很大的影响,粒径越小,大电流性能越好,在2C倍率下,粒径40 μm的炭微球放电容量只有84mAh/g,粒径11μm的炭微球的放电容量仍然保持在223 mAh/g;50次循环后,粒径19 μm的炭微球循环性能最好,保持首次放电容量的92.7%,而粒径40 μm的炭微球只有首次放电容量的70%.     

共沉淀法制备锂离子电池正极材料LiFePO4

采用共沉淀法制备橄榄石结构的LiFePO4锂离子电池正极材料,通过X射线衍射(XRD)、透射电镜(TEM)、循环伏安(CV)和恒电流充放电测试等方法对其结构、表观形貌及电化学性能进行了分析研究.结果表明,该方法制备的LiFePO4为均一的橄榄石型晶体结构,颗粒微细;低倍率下充放电测试比容量可达126.3 mA·h/g;循环性能良好,充放电100次循环后,容量损失率仅为9.4%.     

酚醛树脂炭包覆石墨材料作为锂离子电池负极材料的研究

以液相浸溃法在天然鳞片石墨(NFG)表面包覆酚醛树脂后进行热处理,制备了酚醛树脂炭包覆石墨材料,将这种材料作为锂离子电池的负极材料,运用恒电流充、放电法、粉末微电极循环伏安法考察了其在1 mol/L LiPF_6/(EC+DEC)(1:1)电解液中的充、放电性能,并分析了工艺条件中最高热处理温度(T_max)对其充、放电性能的影响,实验结果表明,经T_max=900℃热处理的酚醛树脂炭包覆石墨材料的第3次稳定放电容量(D_3)为213.75 mA·h/g,第3次充、放电效率(η_3)为88.69％,循环寿命达800次以上,可作为高性能锂离子电池的负极材料。     

铝掺杂磷酸钒锂的制备及电化学性能研究

针对磷酸钒锂电导率低的问题,以硝酸锂、偏钒酸铵、磷酸二氢铵为原料,甘氨酸为络合剂和燃料,葡萄糖为碳源,硝酸铝为铝源,采用溶液燃烧合成法制备铝掺杂的Li_3V_2(PO_4)_3/C粉末,以改善其电化学性能。将制备得到的铝掺杂的Li_3V_2(PO_4)_3/C粉末作为锂离子电池正极材组装成电池进行了恒电流充放电测试、循环伏安(CV)和交流阻抗(EIS)等电化学性能测试。结果表明:铝掺杂能有效提高磷酸钒锂电导率,不同的铝掺杂比例的磷酸钒锂具有不同的的电子电导率和锂离子扩散速率,从而具有不同的放电比容量、循环性能和倍率性能;当铝掺杂含量为1%时,磷酸钒锂具有最优的电化学性能,在充放电速度为10C循环500次后放电容量为104.6 mAh/g。     

全钒液流电池离子交换膜性能研究

考查了全钒液流电池用离子交换膜PE-01膜和Nafion膜的物理和电化学性能.研究表明:全氟化Nafion膜的离子交换容量和化学稳定性优于PE-01膜, Nafion膜的导电性好,适合大电流充放电,但正、负极钒溶液更易于相互渗透,水的转移较快,电池的库仑效率较低.PE-01均相膜的离子水迁移量与VO.2 扩散性比Nafion膜低.     

氧化钨/碳纳米管膜复合负极的制备及其储锂性能

氧化钨(WO₃)因具有较高的理论比容量(693 mAh/g)已成为锂离子电池负极材料的有力候选者。但在电池充放电即锂离子脱/嵌入过程中WO₃会产生较大的体积变化,导致其放电比容量快速衰减,故对其循环稳定性研究仍是热点之一。文中采用水热法和喷涂法分别在碳纳米管膜(CMF)基底上成功合成了水热型-氧化钨/碳纳米管膜(H-WO₃/CMF)和喷涂型-氧化钨/碳纳米管膜(S-WO₃/CMF)复合电极。XRD测试结果显示H-WO₃/CMF和S-WO₃/CMF中的WO₃分别属于单斜相和六方相。将H-WO₃/CMF和S-WO₃/CMF分别组装成扣式电池进行电化学性能测试,结果表明H-WO₃/CMF的首次放电比容量高于S-WO₃/CMF。当H-WO₃/CMF以0.2 C倍率循环时,第1圈放电比容量达到635 mAh/g,循环50圈时放电比容量为510 mAh/g,仍有上升趋势; S-WO₃/CMF在0.2 C倍率下循环时,第1圈放电比容量仅为515 mAh/g,在后续循环过程中容量衰减较快。交流阻抗测试结果显示H-WO₃/CMF的导电性高于S-WO₃/CMF。研究结果表明:H-WO₃/CMF作为锂离子电池负极,有望提升WO₃的电化学稳定性。      

高温固相还原法制备新型锂离子负极材料NbO及其电化学性能

以Nb和Nb2O5粉末为原料,采用高温固相还原法合成NbO电极材料。通过X射线衍射分析(XRD)、扫描电镜(SEM)、激光衍射粒度分析(LDSA)、充放电测试、循环伏安(CV)测试等手段对材料的结构、形貌及电化学性能进行表征,并通过原位XRD分析测试,探究NbO作为负极材料在锂离子电池中的反应机理。结果表明:NbO用作电极材料的平均嵌锂平台在1.6 V左右。NbO对锂的插嵌机理为锂离子的直接脱嵌,是1个单相转变过程。在0.05 C(C为充放电电流倍率)下,NbO和球磨处理后(Ball-milling)的NbO-BM的首次放电容量分别为220(mA·h)/g和280(mA·h)/g,经过50次循环后,剩余容量分别为170(mA·h)/g和220(mA·h)/g     

硅/碳复合材料的高温热解法制备及其电化学性能

采用高温热解方法成功地合成了高容量硅/碳复合负极材料.通过X射线衍射分析、热重分析、扫描电子显微镜观察、透射电子显微镜观察、恒电流充放电测试、循环伏安法等手段研究了复合材料的性能.结果表明:硅/碳复合材料由Si、C以及少量SiO₂组成;硅/碳复合材料中碳的质量分数约在39%左右;经电化学性能测试,在电流0.2 m A下,该硅/碳复合材料首次充电容量768 m Ah·g-1,首次库仑效率75.6%,70次循环后可逆比容量仍为529 m Ah·g-1,平均容量衰减率为0.44%.这些性能改善归因于硅/碳复合材料中碳的引进,硅表面存在的碳涂层提供了一个快速锂运输通道,降低了电池的阻抗并且充放电过程中稳定了电极的组成.      

正极材料LiNi0.8Mn0.2O2前驱体合成工艺的探究

成本低、性能稳定的无钴镍锰正极材料是目前的研究热点。采用共沉淀法制备Ni_0.8Mn_0.2(OH)₂前驱体, 用氨水作为络合剂, 探究了NH₃浓度对前驱体Ni_0.8Mn_0.2(OH)₂共沉淀的晶粒生长和形貌的影响, 以及对锂离子电池正极材料LiNi_0.8Mn_0.2O₂的晶体结构和电化学性能的影响。通过X射线衍射仪、扫描电镜、循环伏安测试、交流阻抗和电池充放电测试系统表征材料的结构、形貌和电化学性能。表征结果显示, 在0.1 C, 2.5~4.2 V化成条件下, 初始放电比容量为167 mAh/g, 充放电效率为96%。当氨水用量为45 mL时, 样品具有较优的循环性能, 在1 C倍率下, 2.5~4.2 V的电压测试范围内, 循环100次后, 放电比容量为139 mAh/g, 容量保持率为93.9%。在低倍率充放电条件下样品具有明显优于其他材料的电化学性能。      

Blood compatibility of amorphous titanium oxide films synthesized by ion beam enhanced deposition

Titanium oxide films were synthesized on titanium, cobalt alloy and low-temperature isotropic pryolytic carbon by ion beam enhanced deposition. The non-stoichiometrical titanium oxide films were obtained. Blood compatibility of the films were evaluated by clotting time measurement, platelet adhesion investigation and hemolysis analyses. The results revealed that blood compatibility of the materials was improved by the coating of titanium oxide films. Semiconductor nature of non-stoichiometric titanium oxide films might be responsible for the improvement of blood compatibility.     

Photoelectrocatalytic Wastewater Treatment Using TiO2/ITO Bilayers Prepared on Optical Fibers by Pulsed Laser Deposition

Advanced oxidation processes (AOPs), on the basis of photoelectrochemical reactions, constitute a good alternative for treating wastewaters contaminated with refractory organic compounds such as dyes. For this purpose, different approaches have been explored to develop novel photoanodes that can be efficiently used in these systems. In this context, this study deals with a comparison of indium tin oxide (ITO) thin films deposited at room temperature by pulsed laser deposition on flat glass and on silica optical fiber (SiO2 core, 600?μm diameter) substrates. Characterization data reveal that nanostructured ITO thin films with resistivity values from 4.4×10-2 to 5.6×10-4??Ω·cm were obtained. To build the photoanode, the ITO thin films were coated with a TiO2 layer deposited by using the electrophoretic method. The prepared TiO2/ITO bilayers on optical fibers showed a better photocatalytic performance than those deposited on flat glass substrates according to TOC and color removal measurements from dye contaminated water samples. These results suggest that the deposited materials exhibit suitable properties for their application in photoelectrocatalytic devices that, employing optical fiber as support and light transmitter, can be efficiently used for the elimination of organic contaminants in industrial wastewaters.     

X-Ray Diffraction Analysis of Residual Stress in Thin Polycrystalline Anatase Films and Elastic Anisotropy of Anatase

The importance of residual stress in anatase thin films for their photo-induced hydrophilicity was proved recently. Detailed X-ray diffraction (XRD) studies of residual stresses in titanium dioxide films are presented here. Measurements including multiple hkl reflections on several series of these films revealed the presence of tensile stresses in the films that were obtained by crystallization from amorphous state. Significant anisotropy of the strain was also found and compared with that of anatase, resulting from its theoretically calculated single-crystal elastic constants. The XRD data support the experimental evidence of the hypothesis that the [00l] axis is the elastically soft anatase direction, whereas the directions in the [h00] × [hk0] plane are elastically stiff. This is in agreement with the anisotropy predicted by single-crystal elastic constants that are obtained from ab-initio calculations. Residual stress analysis for materials with tetragonal symmetry is described and the theory is used to analyze the data. The anisotropy is very different from that for the rutile phase, and the experimental results agree well with the values calculated for anatase. A simplified method of XRD residual stress analysis in thin anatase films by total pattern fitting (TPF) is also presented. Tensile stresses are formed during the crystallization process and increase rapidly with reduced film thickness. They inhibit crystallization, which is then very slow in the thinnest films.     

Mechanical properties and deformation behavior of amorphous nickel-phosphorous films measured by nanoindentation test

In this study, amorphous Ni-P films were deposited by electroless plating under different pH values. Their mechanical properties and deformation behavior were then investigated by instrumented nano-indentation. With increasing pH value of the plating solution from 3.75 to 6.0, the hardness and elastic modulus of the obtained Ni-P films increased from 6.1 GPa and 146 GPa to 8.2 GPa and 168 GPa respectively. From the load-indentation depth curve, the Ni-P films were found to yield at an indentation depth of 8 nm. By microstructural examination around the indented regions, early-stage plastic deformation of the amorphous Ni-P films was verified through the formation and extension of shear bands with a spacing of several tens of nanometers. Within the shear bands, flow dilatation-induced intense shear localization was expected and resulted in crystallization in the amorphous matrix. The critical shear stress and energy release rate required for the initiation of early-stage plastic yielding of the Ni-P films were calculated to be about 1.4 GPa and 3.0 J/m² respectively, both of which increased with pH values.     

Influence of porosity and sliding rate on the tribotechnical properties and features of deformation of the surface layers of copper-graphite materials during friction without lubrication

Conclusions The relationship of the intensity of wear of a copper-graphite material containing 10% graphite to porosity has an extreme character. The optimum antifriction properties are obtained with a porosity of 6–12%. In this interval of porosities the minimum degree of deformation of the surface layer in friction is observed. The minimum values of the intensity of wear and of the coefficient of friction of copper-graphite materials are observed in the 2.6–22 m/sec range of sliding rates, at which solid films of secondary structures distinguished by low roughness are formed on the surface.Translated from Poroshkovaya Metallurgiya, No. 8(296), pp. 81–85, August, 1987.     

Protein adsorption and endothelial cell attachment and proliferation on PAPI-based additive modified poly(ether urethane ureas)

To better understand vascular interactions with poly(ether urethane urea) (PEUU) materials, protein adsorption, and endothelial cell attachment and proliferation assays were performed on a base PEUU formulation, on PEUU formulations loaded with hydrophobic and amphiphilic poly(methylene-[polyphenyl isocyanate]) (PAPI) based additives, and on PEUU formulations in which some of the polymer chains had been endcapped with either diisopropylaminoethyl (DIPAA) or decyl (DA) moieties. Protein adsorption experiments with PAPI-based additives showed that additive loaded PEUU formulations adsorbed significantly lower amounts of the studied proteins than did the unloaded PEUU. Protein adsorption to the DA and DIPAA endcapped PEUU films was found not to vary consistently from that of the unloaded PEUU film. Endothelial cell attachment and proliferation experiments with PAPI-DA and polyethylene glycol-PAPI-DA (PEG-PAPI-DA) loaded PEUU films showed that many of the films exhibited attachment and proliferation that was significantly enhanced compared to PEUU A' and that approached or equaled that of the tissue culture polystyrene control. Experiments with PAPI-DIPAA and PEG-PAPI-DIPAA loaded PEUU films exhibited attachment and proliferation data that was often below 10% of the tissue culture polystyrene control values. Experiments with the DA and DIPAA endcapped PEUU films showed endothelial cell attachment and proliferation that was statistically indistinguishable from the PEUU A' values. Contact angle analysis was carried out on the endcapped PEUU films, on the PAPI-based additive loaded PEUU films, and on PEUU A' using the sessile drop method. The advancing and receding contact angle behavior of the PAPI-based additive loaded PEUU films deviated markedly from the behavior of PEUU A', suggesting that the additives were present at the PEUU-water interface. The contact angle behavior of the endcapped PEUUs was similar to that of PEUU A', suggesting that the DA and DIPAA endcap moieties did not exist at the hydrated PEUU surface in appreciable quantities. To explain the differences in protein adsorption and endothelial cell behavior on the air side of additive loaded PEUUs when compared to the base PEUU, it was assumed that the additives near this region of the solvent swollen PEUU matrix may have migrated to, at, or near the PEUU-air interface during film formation, creating an additive enriched PEUU surface region.(ABSTRACT TRUNCATED AT 400 WORDS)     

Nanoscale Hybrid Langmuir－Blodgett Films Based on Cerium－Substituted Heteropolymolybdate and Polyquinoline

Nanoscale hybrid organic/inorganic Langmuir-Blodgett films of cerium-substituted heteropolymolybdates (CeHPMo) and π-conjugated macromolecule poly(1,2-dihydro-2,2,4-trimethyl) quinoline (PQ) were obtained with auxiliary film-forming material stearic acid(SA) or octadecylamine(ODA). The surface pressure-area isotherms illuminate the formation of the hybrid LB films of PQ/ODA/Ce-HPMo and PQ/SA/Ce-HPMo. The different film-forming mechanism was discussed when the different auxiliary film-forming materials were used in the system. The absorption spectra indicate that the molecules of PQ and Ce-HPMo are incorporated into the LB films. Tapping-mode AFM image reveals a granular surface texture of nanosized Ce-substituted heteropolymolybdate. STM image shows that the conductivity is greatly improved after Ce-substituted heteropolymolybdates are incorporated in the films.     

Drawn gelatin films with improved mechanical properties

Chain anisotropic distribution in gelatin films has been obtained by uniaxial stretching at constant relative humidity, followed by air drying and successive cross-linking with glutaraldehyde. The drawn samples have been characterized by mechanical tests, differential scanning calorimetry and scanning electron microscopy. The Young's modulus, E, and the stress at break, sigma(b), increase linearly with the draw ratio and reach values which are about five times those characteristic of undrawn samples. Furthermore, on stretching the alignment of the gelatin strands along the direction of deformation increases while the thickness of the layers decreases significantly. The renaturation level, that is the fraction of gelatin in a collagen-like structure, has been calculated as the ratio between the melting enthalpy of gelatin samples and that of tendon collagen. The results indicate that the improvement of mechanical properties achieved by drawn gelatin is closely related to the renaturation level. The experimental approach utilized to induce segmental orientation in gelatin films, allows to obtain anisotropic materials with improved mechanical properties in the direction of deformation, and can be usefully applied in the preparation of biomaterials.     

Collagen packing in the dogfish egg case wall

Gompertz and logistic models were fitted to experimental counts of microorganisms growing in beef stored at 0, 4, 7, 9 and 10 degrees C. Samples were packaged in polyethylene (high gaseous permeability) and in EVA/SARAN/EVA (low gaseous permeability) films, being EVA ethyl vinyl acetate and SARAN polyvinyl and polyvinylidene chloride copolymer. Lag phase duration (LPD) and specific growth rate (mu) were obtained as derived parameters for lactic acid bacteria, Enterobacteriaceae, Pseudomonas sp. and psychrotrophic microorganisms. The reciprocal of LPD was fitted to an Arrhenius type equation; LPD of lactic acid bacteria showed a marked dependence on temperature, with activation energy values (ELPD) of 222.2 and 216.9 kJ/mol for polyethylene and ESE respectively. The effect of initial microbial population at different storage temperatures on adaptation period was analyzed. As the initial microbial population increased, adaptation period decreased for all studied microorganisms and for both packaging films. The effect of temperature on specific growth rate was better interpreted by the Arrhenius model than by the linear or the square root equations. Psychrotrophic microorganisms in beef showed the highest activation energy values for specific growth rate (E mu) in both packaging films, being E mu 85.50 and 103.10 KJ/mol for polyethylene and ESE film respectively. In both films, Enterobacteriaceae showed the lowest E mu values, being 15.33 and 59.89 kJ/mol in ESE and polyethylene respectively. The final number of microorganisms (maximum population density) did not show significant changes with storage temperature.     

Phase formation and microstructure in sputter-deposited Ti-Mo-C and Ti-W-C thin films

Ti-Mo-C and Ti-W-C films were deposited by cosputtering from carbide targets in order to examine the phase formation, microstructure, and mechanical properties. A series of Ti-Mo-C films were deposited, with compositions ranging from TiC to Mo₂C. The X-ray diffraction (XRD) analysis showed that multiphase Ti-Mo-C films, containing the (Ti,Mo)C, Mo₂C, and Mo₃C₂ phases, were only obtained in highly Mo-rich films. The transmission electron microscopy (TEM) analysis showed a higher defect content in single-phase alloy Ti-Mo-C films in comparison to TiC alone. The hardness for most Ti-Mo-C films was in the range of 8 to 10 GPa, but even lower values were obtained in the multiphase films. Ti-W-C films deposited by cosputtering of TiC and WC formed only (Ti,W)C solid solutions. The X-ray photoelectron spectroscopy (XPS) analysis of peak positions showed that the W 4f _7/2 binding energy decreased with increasing W content. The hardness of most of the Ti-W-C coatings was in the range of 15 to 17 GPa; however, a sample with 40 pct W had a hardness of 29 GPa. The TEM analysis of this sample revealed an extremely small grain size and a higher film density. The high hardness of this specimen is attributed to Hall-Petch strengthening.