Yin Geping

Studies on the anodic behavior of aluminum electrodes in alkaline solution

Abstract An efficient process for developing aluminum alloys for alkaline battery anodes is described. The addition of gallium to aluminum eliminates remarkably the anisotropy of aluminum, and thus renders its electrode potential more negative. The uniform distribution of alloying elements is an essential factor for lowering the corrossion rate of the alloy. The accumulation of an alloying element at intergranular bounderies, or the formation of a secondary phase that contains the element, will result in a rise in the corrosion rate of aluminum.

Synthesis and Characterization of ZnFe

以ZnCl 2 和FeCl 3 ·6H 2 O为原料, 通过溶剂热法制备了尖晶石型ZnFe 2 O 4 材料, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅立叶红外光谱(FT-IR)和恒流充放电测试技术对材料的结构、形貌及电化学性能进行了表征。结果表明, 合成的材料为纳微多孔结构, 其颗粒粒径约为250 nm, 以50 mA/g的电流密度充放电时, 可逆比容量为933.1 mAh/g, 经过100次循环后, 比容量为813.5 mAh/g, 比容量保持率高达87.2%, 表现出优异的循环稳定性能。当电流密度增大到400 mA/g时, 其比容量约为355 mAh/g, 表现出较高的倍率性能。采用该法制备得到的纳米ZnFe 2 O 4 具有比容量高、循环稳定好等优点, 是一种具有较强应用前景的锂离子电池负极材料。以ZnCl 2 和FeCl 3 ·6H 2 O为原料, 通过溶剂热法制备了尖晶石型ZnFe 2 O 4 材料, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅立叶红外光谱(FT-IR)和恒流充放电测试技术对材料的结构、形貌及电化学性能进行了表征。结果表明, 合成的材料为纳微多孔结构, 其颗粒粒径约为250 nm, 以50 mA/g的电流密度充放电时, 可逆比容量为933.1 mAh/g, 经过100次循环后, 比容量为813.5 mAh/g, 比容量保持率高达87.2%, 表现出优异的循环稳定性能。当电流密度增大到400 mA/g时, 其比容量约为355 mAh/g, 表现出较高的倍率性能。采用该法制备得到的纳米ZnFe 2 O 4 具有比容量高、循环稳定好等优点, 是一种具有较强应用前景的锂离子电池负极材料。

lt;inf

Abstract Pieces of nonpulverized misch metal (Mm) alloy were used as working electrodes (WEs). The WEs were cathodically charged in H2 and O2 atmospheres, respectively, and the electrode potentials were determined. The morphologies of definite areas of WEs were observed by SEM, and the surface composition in chemical elements of these areas were determined by EPMA. The results indicated that the main causes of the degradation of WEs might be the increase of internal stress, the expansion of crystal lattice, and the preferential dissolution of Mm during charging, rather than the oxidation of the alloy by O2, which was accordant with the presence of La3+ and Ni2+ in the MH electrode of MH/Ni batteries after cycling.

gt;2

通过循环伏安(CV)、电化学阻抗谱(EIS)、扫描电子显微镜(SEM)、X射线光电子能潜(XPS)和傅立叶变换红外(FTIR)光谱研究了双乙二酸硼酸锂(LiBOB)基电解液在石墨表面的成膜性及其在常温(25℃)和高温(70℃)下对石墨循环性能的影响.结果表明,LiBOB基电解液的成膜电位在1.7 V,其中BOB-离子还原形成的草酸盐是同体电解质相界面(SEI)膜的有效成分之一.电化学阻抗谱显示,膜...

lt;/inf

以ZnCl 2 和FeCl 3 ·6H 2 O为原料, 通过溶剂热法制备了尖晶石型ZnFe 2 O 4 材料, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅立叶红外光谱(FT-IR)和恒流充放电测试技术对材料的结构、形貌及电化学性能进行了表征。结果表明, 合成的材料为纳微多孔结构, 其颗粒粒径约为250 nm, 以50 mA/g的电流密度充放电时, 可逆比容量为933.1 mAh/g, 经过100次循环后, 比容量为813.5 mAh/g, 比容量保持率高达87.2%, 表现出优异的循环稳定性能。当电流密度增大到400 mA/g时, 其比容量约为355 mAh/g, 表现出较高的倍率性能。采用该法制备得到的纳米ZnFe 2 O 4 具有比容量高、循环稳定好等优点, 是一种具有较强应用前景的锂离子电池负极材料。以ZnCl 2 和FeCl 3 ·6H 2 O为原料, 通过溶剂热法制备了尖晶石型ZnFe 2 O 4 材料, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅立叶红外光谱(FT-IR)和恒流充放电测试技术对材料的结构、形貌及电化学性能进行了表征。结果表明, 合成的材料为纳微多孔结构, 其颗粒粒径约为250 nm, 以50 mA/g的电流密度充放电时, 可逆比容量为933.1 mAh/g, 经过100次循环后, 比容量为813.5 mAh/g, 比容量保持率高达87.2%, 表现出优异的循环稳定性能。当电流密度增大到400 mA/g时, 其比容量约为355 mAh/g, 表现出较高的倍率性能。采用该法制备得到的纳米ZnFe 2 O 4 具有比容量高、循环稳定好等优点, 是一种具有较强应用前景的锂离子电池负极材料。

gt;O

This research aims at increasing the utilization of platinum-ruthenium alloy (Pt-Ru) catalysts and thus lowering the catalyst loading in anodes for methanol electrooxidation. The direct methanol fuel cell’s (DMFC) anodic catalysts, Pt-Ru/C, were prepared by chemical reduction with a reducing agent added in two kinds of solutions under different circumstances. The reducing agent was added in hot solution with the protection of inert gases or just air, and in cold solution with inert gases. The catalysts were treated at different temperatures. Their performance was tested by cyclic voltammetry and potentiostatic polarization by utilizing their inherent powder microelectrode in 0.5 mol/L CH3OH and 0.5 mol/LH2SO4 solution. The structures and micro-surface images of the catalysts were determined and observed by X-ray diffraction and transmission electron microscopy, respectively. The catalyst prepared in inert gases showed a better catalytic performance for methanol electrooxidation than that prepared in air. It resulted in a more homogeneous distribution of the Pt-Ru alloy in carbon. Its size is small, only about 4.5 nm. The catalytic performance is affected by the order of the reducing agent added. The performance of the catalyst prepared by adding the reductant at constant temperature of the solution is better than that prepared by adding it in the solution at 0°C and then heating it up to the reducing temperature. The structure of the catalyst was modified, and there was an increase in the conversion of ruthenium into the alloyed state and an increase in particle size with the ascension of heat treatment temperature. In addition, the stability of the catalyst was improved after heat treatment.