新型储氢合金电极Ti_3Ni_2的电化学性能

研究了新型储氢合金电极 Ti3Ni2 的电化学性能。实验结果表明 :Ti3Ni2 合金电极的最大放电容量达到384.4m Ah/ g(35 3K) ,相当于 Ti3Ni2 H3.7;在 2 78K,最大容量为 145 .5 m Ah/ g,相当于 Ti3Ni2 H1 .47。高温条件下(35 3K)放电曲线有 2个平台 ,在温度比较低时 ,放电曲线只有 1个平台 ;与 Ml(Ni Co Mn A1) 5 合金相比 ,Ti3Ni2 合金电极的动力学性能不好。此外 ,温度对 Ti3Ni2 合金电极的电化学性能影响明显。在温度比较高的条件下 ,合金的放电容量、动力学特性、荷电保持能力均有大幅改善。     

温度对La-Mg-Ni-Co-Mn贮氢电极合金电化学性能的影响

系统研究了温度对La07Mg03Ni2875Co0.525Mn0.1贮氢合金电化学性能尤其是电化学动力学性能的影响.结果表明:La07Mg03Ni2 875Co0525Mn0,合金由(La,Mg)Ni3相和LaNi5相构成.合金的最大放电容量随着温度升高从-20℃时的277.5 mAh/g增加到30℃时的406.2 mAh/g.随着温度升高,合金放电平台电位逐渐变负,放电过电位逐渐减小,合金电极的极化减弱.高倍率性能、交换电流密度、氢的扩散系数研究表明合金的电化学动力学性能随着温度升高不断提高.该合金的氢扩散活化能为17.6 KJ/mol.     

CeMn0.25Al0.25Ni1.5+x(x=0.0, 0.3, 0.5, 0.7, 0.9, 1.1)合金的相结构和电化学性能

研究了CeMn0.25Al0.25Ni1.5+x(x=0.0,0.3,0.5,0.7,0.9,1.1)超化学计量比合金的相结构和电化学性能。XRD、SEM和电化学性能测试结果表明:CeMn0.25Al0.25Ni1.5+x(x=0.0,0.3,0.5,0.7,0.9,1.1)合金主要含有六方的CeAl相和立方的CeNi相,合金的粒径随x值的增大而变大。Ni的超化学计量比添加能够大大提高合金的电化学活性,298K时,合金的放电容量从x=0.0时的118.3mAh/g提高到x=1.1时的200.7mAh/g;338K时,其放电容量随x值增大呈先增后减的趋势,x=0.0合金的放电容量为170.4mAh.g-1,当x=0.9时,放电容量出现最大值271.4mAh/g。合金电极的P-C-T曲线表明:随Ni超化学计量的增加,合金的平衡氢压平台斜率变小,宽度增大,平衡氢压升高,这可能是使合金电极放电容量增加的主要原因。     

铸态及退火La1.9Ti0.1MgNi9合金的贮氢性能

采用磁悬浮感应熔炼及退火处理的方法,制备La1.9Ti0.1MgNi9合金。对合金样品的XRD、PCT和电化学测试表明,所有样品均由多相组成,LaNi5相为主相。当退火温度达到1173 K时,合金中LaMg2Ni9相消失,Ti2Ni相出现。退火处理能提高合金的晶化程度、降低吸放氢平台压。退火1073 K合金的有效吸氢量较高,在303 K时达到1.25% (质量分数)。La1.9Ti0.1MgNi9合金退火后,放电容量、循环稳定性以及高倍率放电性能得到极大改善,以1173 K退火合金电化学性能较好,其最大放电容量为377 mAh/g,1100 mA/g电流密度下的高倍率放电性能为0.839,经112次充放电循环后放电容量保持率为60%。     

Electrochemical Properties and Reaction Mechanism of Ti-V Multiphase Alloy at High Temperature

研究333 K时Ti0.17Zr0.08V0.35Cr0.1Ni0.3 合金的循环稳定性和高温倍率放电性能。333 K时,当放电电流密度为60 mA/g时,Ti0.17Zr0.08V0.35Cr0.1Ni0.3合金第1次放电容量为450 mAh/g。随着充放电循环的进行,放电容量迅速降低。当放电电流密度为2400 mA/g,截止电压为0.6 V时,Ti0.17Zr0.08V0.35Cr0.1Ni0.3合金的放电容量仍达到160 mAh/g。并详细探讨影响以上合金电化学性能的因素     

贮氢合金La0.65Mg0.35Nix（x=3.0～3.5）高温电化学性能的研究

研究了La0.65Mg0.35Nix（x=3.0、3.1、3.2、3.3、3.4、3.5）稀土镁基贮氢合金电极的高温（333 K）放电性能。该系列合金电极在70 mA.g1放电电流密度下的高温放电容量随Ni含量的增加逐渐降低,x=3.0的合金在333K的放电容量（293.4 mAh.g-1）可以达到常温（298 K）放电容量的97.8%。333 K的电化学P-C-T曲线测试结果表明,随着Ni含量的增加,放氢平台明显变窄,吸/放氢平台的滞后增加,说明Ni含量的增加不利于改善合金电极的放电性能。腐蚀曲线测量结果表明,随着Ni含量的增加,合金的抗腐蚀性能逐渐减弱。     

快速凝固Ti-Zr-Ni合金的电化学贮氢性能

采用铜辊快速凝固方法制备了Ti45Zr30Ni25和Ti50Zr25Ni25合金,并对合金作为镍-氢二次电池负极的动力学和电化学性能进行了研究.结果表明,Ti45Zr30Ni25为非晶相合金,Ti50Zr25Ni25合金由准晶相和非晶相组成.两合金电极的最大放电容量分别为129和132mAh/g.在240mA/g电流密度下,高倍率放电性能(HRD)分别为62.7%和63.3%.合金电极的交换电流密度分别为205.1和375.6mA/g,氢在合金中的扩散系数分别为5.4×10-11和5.8×10-11cm2·S-1.     

热处理对包含正二十面体准晶相Ti_(1.4)V_(0.6)Ni合金电极的电化学性能的影响(英文)

研究了热处理前后Ti1.4V0.6Ni合金的结构和电化学性能。采用X射线粉末衍射(XRD)方法分析合金的结构。电化学特性包括放电容量、循环稳定性和高倍率放电性能等。XRD衍射分析表明,在590°C热处理30min的合金,主要包含正二十面体准晶相、Ti2Ni(FCC)相、V基固溶相(BCC)和C14Laves相(Hex)。电化学测试显示,热处理后在30°C和放电电流密度为30mA/g的条件下,合金电极的最大放电容量可达330.9mA·h/g,并且循环稳定性和高倍率放电性能也得到改善。此外,通过电化学阻抗和合金内部氢的扩散系数研究了合金电极的动力学性能。     

热处理对包含正二十面体准晶相Ti1.4V0.6Ni合金电极的电化学性能的影响（英文）

研究了热处理前后Ti1.4V0.6Ni合金的结构和电化学性能。采用X射线粉末衍射(XRD)方法分析合金的结构。电化学特性包括放电容量、循环稳定性和高倍率放电性能等。XRD衍射分析表明,在590°C热处理30min的合金,主要包含正二十面体准晶相、Ti2Ni(FCC)相、V基固溶相(BCC)和C14Laves相(Hex)。电化学测试显示,热处理后在30°C和放电电流密度为30mA/g的条件下,合金电极的最大放电容量可达330.9mA·h/g,并且循环稳定性和高倍率放电性能也得到改善。此外,通过电化学阻抗和合金内部氢的扩散系数研究了合金电极的动力学性能。     

Hydrogen Storage Properties of Co-free La-Mg-Ni-Based Alloys

在Ar气保护下采用磁悬浮感应熔炼方法,制备无CoLa1.8Ti0.2MgNi9-xAlx(x=0,0.1,0.2,0.3,0.4)合金,系统研究Al取代Ni对合金的结构及贮氢性能的影响。所有合金均包含LaMg2Ni9相,当Al含量x≥0.1,La(Ni,Al)5相取代LaNi5相、LaNi3相消失、LaNi2相出现。测试合金的焓变值与LaNi5合金(–30.6kJ/molH2)相近。Al取代Ni不仅提高合金电极的放电容量,而且改善循环稳定性及电化学动力学性能。La1.8Ti0.2MgNi8.7Al0.3合金贮氢性能较好,30℃下有效吸氢质量分数为1.32%;最大放电容量达到340mAh/g;1400mA/g放电电流密度下高倍率放电性能HRD1400高达79.8%;经100次充放电循环放电容量保持率为60%。     

X-ray diffraction study of Ba0.985Na0.015Ti0.985Nb0.015O3, Ba0.6Na0.4Ti0.6Nb0.4O3 and Ba0.3Na0.7Ti0.3Nb0.7O3 compositions

The Ba_0.985Na_0.015Ti_0.985Nb_0.015O₃, Ba_0.6Na_0.4Ti_0.6Nb_0.4O₃ and Ba_0.3Na_0.7Ti_0.3Nb_0.7O₃ compositions of the (1 − x) BaTiO₃–xNaNbO₃ (BTNNx) system have been studied by X-ray diffraction and by measurements of dielectric properties. The specimens with composition BTNN (x = 0.015, 0.40 and 0.70) have been refined by the JANA program from X-ray powder diffraction data. Ceramic samples with composition (1 − x) BaTiO₃ + xNaNbO₃ (where x = 0.015, 0.40 and 0.70) were prepared by calcinations from appropriate mixture of BaCO₃, TiO₂, Na₂CO₃ and Nb₂O₅. The calcined powder was sintered at temperature range 1200–1400 °C. As the composition x increased from 0.015 (and 0.70), the ferroelectric ceramics (x = 0.015, FE) with tetragonal phase changed to the ferroelectric relaxors (RFE, x = 0.40). RFE ceramics showed a peculiar diffuse phase transition and dielectric relaxation at the low temperature (down to 180 K) due to a frustration between RFE and FE state. These ceramics present the classical ferroelectric character when 0 ≤ x < 0.075 and 0.55 < x ≤ 1 and relaxor character when 0.075 ≤ x ≤ 0.55.     

Magnetic, electrical and plastic properties of Fe76Nb2Si13B9, Fe75Ag1Nb2Si13B9 and Fe75Cu1Nb2Si13B9 amorphous alloys

Influence of 1 h annealing in vacuum on magnetic, electrical and plastic properties of Fe₇₆Nb₂Si₁₃B₉, Fe₇₅Ag₁Nb₂Si₁₃B₉ and Fe₇₅Cu₁Nb₂Si₁₃B₉ melt spun ribbons were carefully investigated. It was shown that in all cases soft magnetic properties can be significantly enhanced by applying 1-h annealing at characteristic temperatures T_op. This optimization annealing causes that permeability increases more than 15-times and magnetic losses (tangent of loss angle) achieves a minimum in relation to the as quenched state. Using structural examinations (X-ray and HRTEM) it was shown that for the Fe₇₅Cu₁Nb₂Si₁₃B₉ alloy the optimized microstructure corresponds to a nanocrystalline αFe(Si) phase whereas in other alloys to a relaxed amorphous phase free of iron nanograins. As a consequence of this fact the Fe₇₆Nb₂Si₁₃B₉ and Fe₇₅Ag₁Nb₂Si₁₃B₉ alloys show higher plasticity in comparison to the nanocrystalline Fe₇₅Cu₁Nb₂Si₁₃B₉ alloy. Temperatures of the first stage of crystallization, and related diffusion parameters were determined using measurements of resistivity versus temperature with different heating rates.     

Fe2+-Ni2+-NH3-NH4+-C2O42-H2O体系的沉淀配合平衡热力学

针对草酸盐配位共沉淀热分解还原法制备超细铁镍合金粉过程中Fe2+-Ni2+-NH3-NH4+-C2O42--H2O体系的溶液平衡建立热力学分析模型,并根据模型进行相关计算,揭示反应体系中各物质随pH值、氨及草酸浓度的变化关系。结果表明:溶液中的Fe主要以[Fe(C2O4)n]2 2n络合物形式存在,而铁氨络合物含量很低。当氨含量较低时,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在;氨含量较高时,在酸性条件下,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在,在碱性条件下,则主要以[Ni(NH3)n]2+存在。低pH值下,Ni的沉淀率较Fe的高,而高pH值下,Ni的沉淀率则较Fe的低。     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

New Zr6CoAs2-type compounds: Y6CoBi2, Ho6CoBi2 and Tm6CoBi2

Results of a powder X-ray diffraction investigation of new ternary compounds are reported. The compounds Y₆CoBi₂ [a=0.8312(1) nm, c=0.4144(1) nm], Ho₆CoBi₂ [a=0.8246(2) nm, c=0.4095(1) nm], and Tm₆CoBi₂ [a=0.8155(2) nm, c=0.4066(1) nm] crystallize in the hexagonal Zr₆CoAs₂-type structure (space group P6b2m No. 189). The Zr₆CoAs₂-type structure is a superstructure of the Fe₂P-type structure.     

Zur Kenntnis von RbBa3Ca4Cu3V7O28

Single crystals of RbBa₃Ca₄Cu₃V₇O₂₈ were prepared above the melting point of the reaction mixture. It crystallizes with hexagonal symmetry, space group C_6V⁴-P6₃mc, a 11.1751, c 12.434 Å, Z = 2. RbBa₃Ca₄Cu₃V₇O₂₈ is the second member of a new structure type of the copper-oxovanadates. Ba²⁺ shows an unusual 12-fold coordination. The two calcium positions are coordinated by trigonal prisms and octahedra respectively. The copper coordination is characterized by a stretched square pyramid. The Cu²⁺ ions are outside the centre nearly in plane of the pyramids.

Zusammenfassung

Einkristalle von RbBa₃Ca₄Cu₃V₇O₂₈ wurden oberhalb des Schmelzpunktes der Reaktionsmischung erhalten. Die Verbindung kristallisiert hexagonal, Raumgruppe C_6V⁴-P6₃mc, a 11.1751, c 12.434 Å, Z = 2. RbBa₃Ca₄Cu₃V₇O₂₈ ist das zweite Beispiel für einen neuen Strukturtyp der Kupfer-Oxovanadate, mit 12-fach koordinierten Ba²⁺ -Ionen. Die zwei Calciumpositionen sind trigonal prismatisch bzw. oktaedrisch koordiniert. Die Koordination der Cu²⁺-Ionen ist durch eine gestreckte Pyramide charakterisiert. Cu²⁺ ist auβerhalb des Polyederzentrums nahezu in der quadratischen Fläche der Pyramide angeordnet.     

Al2O3-Sm2O3-CeO2电解质的性能（英文）

采用溶胶-凝胶法和低温燃烧技术制备Ce1-xSmxO2（x=0,0.1,0.2,0.3）和掺杂Sm和（2%-8%）Al2O3的二氧化铈;研究其合成、结构、致密化、导电性和热膨胀等性能,并利用XRD研究其结构和相组成。结果表明,于1300°C烧结球团,获得致密的陶瓷,于1250°C在Ce0.8Sm0.2O0.2中加入2%和4%的Al2O3以促进烧结。利用扫描电子显微镜观察烧结后球团的表面形貌,使用双探针交流阻抗谱研究总离子电导率。     

电弧喷涂制备Fe65Cr20Mo7B3.5SiMn1.5W3涂层

在Q235低碳钢板上利用电弧喷涂工艺进行喷涂,以制得Fe65Cr20Mo7B3.5SiMn1.5W3涂层。喷涂材料为自行配制的丝材,按照35%的填充率将配好的粉填充到U型不锈钢外皮中,经过多道拉拔、挤压工艺制成Φ2mm的粉芯丝材。采用X射线衍射仪、扫描电镜、能谱分析仪、透射电镜对涂层的物相和组织形貌及成分进行了表征;采用差示扫描量热仪、显微硬度仪等设备对涂层的热稳定性及显微硬度进行了检测和分析。试验结果表明:涂层组织形貌呈典型的层状组织结构,由变形良好的带状粒子相互搭接堆积而成。涂层含有50.63%的非晶相,同时含有纳米级的晶相。涂层组织均匀、结构致密、孔隙率低,并且涂层硬度高达1040.5HV0.3,属硬质涂层,具有良好的热稳定性。     

Synthesis and electrochemical properties of LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12

Spinel compound LiNi_0.4Mn_1.5Cr_0.1O₄ (LNMCO) and Li₄Ti₅O₁₂ (LTO) were synthesized by the sol-gel method and the solid-state method, respectively. The particle sizes of the products LiNi_0.4Mn_1.5Cr_0.1O₄ and Li₄Ti₅O₁₂ were 0.5 to 2 um and 0.5 to 0.8 um, respectively. All samples exhibited excellent electrochemical properties. A LiNi_0.4Mn_1.5Cr_0.1O₄/Li₄Ti₅O₁₂ (LNMCO/LTO) cell was fabricated and was demonstrated to exhibit good electrochemical properties at the high current rate of 1 C. When the specific capacity was determined based on the mass of the LNMCO cathode, the LNMCO/LTO cell delivered 125 mAh g⁻¹ at 1 C and 77 mAh g⁻¹ at 5 C. The capacity retentions after 30 cycles were 94.4 % and 83.1 %, respectively.