利用简单刮涂的方式将四种不同的金属有机骨架材料(MOF)分别与聚偏二氟乙烯(PVDF)复合制备得到柔性MOF/PVDF多孔隔膜,研究其在锂金属电池中对锂离子传输沉积行为的影响。结果表明,MOF基隔膜很好地引导了锂离子在锂金属负极的沉积,另外,...利用简单刮涂的方式将四种不同的金属有机骨架材料(MOF)分别与聚偏二氟乙烯(PVDF)复合制备得到柔性MOF/PVDF多孔隔膜,研究其在锂金属电池中对锂离子传输沉积行为的影响。结果表明,MOF基隔膜很好地引导了锂离子在锂金属负极的沉积,另外,电极的界面电荷传输性质也得到了改善,界面反应动力学有所提升。在0.5C电流密度下,MOF/PVDF隔膜组装的LTO电池在150圈时的放电容量依旧保持在165~170 mAh g^(-1)左右,相较于普通隔膜电池的157.8 mAh g^(-1)有明显的提升。展开更多
CeO2 and Ce0.8M0.2O2-d films （M = Mn, Y, Gd, Sm, Nd and La） with （00l） preferred orientation have been prepared on biaxially textured Ni-W substrates by metal organic decomposition （MOD） method. The factors infl...CeO2 and Ce0.8M0.2O2-d films （M = Mn, Y, Gd, Sm, Nd and La） with （00l） preferred orientation have been prepared on biaxially textured Ni-W substrates by metal organic decomposition （MOD） method. The factors influencing the formation of cracks on the surface of these CeO2 and doped CeO2 films on Ni-W substrates were explored by X-ray diffraction （XRD）, scanning electron microscopy （SEM） analysis, atomic force microscopy （AFM） and differential scanning calorimetry （DSC）. The results indicate that many factors, such as the change of the ionic radii of doping cations, the transformation of crystal structure and the formation of oxygen vacancies in lattices at high annealing temperature, may be related to the formation of cracks on the surface of these films. However, the crack formation shows no dependence on the crystal lattice mismatch degree of the films with Ni-W substrates. Moreover, the suppression of surface cracks is related to the change of intrinsic elasticity of CeO2 film with doping of cations with a larger radius. SEM and AFM investigations of Ce0.8M0.2O2-d （M = Y, Gd, Sm, Nd and La） films reveal the dense, smooth and crack-free microstructure, and their lattice parameters match well with that of YBCO, illuminating that they are potentially suitable to be as buffer layer, especially as cap layer in multi-layer architecture of buffer layer for coated conductors.展开更多
YBa2Cu3O7-x(YBCO) films were fabricated on an LAO substrate using the trifluoroacetic acid-metal organic deposition(TFA-MOD) method and the effects of the humidity and heat treatment temperatures on the microstructure...YBa2Cu3O7-x(YBCO) films were fabricated on an LAO substrate using the trifluoroacetic acid-metal organic deposition(TFA-MOD) method and the effects of the humidity and heat treatment temperatures on the microstructure,degree of texture and critical properties of the films were evaluated.In order to understand the combined effects of the humidity and the calcining and firing temperatures on critical properties,heat-treatment was performed at various temperatures with the other processing variables fixed.The films were calcined at 400-430 ℃ and fired at 750-800 ℃ in a 0-12.1% humidified Ar-O2 atmosphere.The texture was determined by pole-figure analysis.The amount of the BaF2 phase was effectively reduced and a sharp and strong biaxial texture was formed under a humidified atmosphere,which led to increased critical properties.In addition,the microstructure varied significantly with firing temperature but changed little with calcining temperature.The highest IC of 40 A/cm-width,which corresponds to JC value of 1.8 MA/cm2,was obtained for the films fired at 775 ℃(in 12.1% humidity) after calcining at 400-430 ℃.It is likely that the highest IC value is due to the formation of a more pure YBCO phase,c-axis grains,and a denser microstructure.展开更多
文摘利用简单刮涂的方式将四种不同的金属有机骨架材料(MOF)分别与聚偏二氟乙烯(PVDF)复合制备得到柔性MOF/PVDF多孔隔膜,研究其在锂金属电池中对锂离子传输沉积行为的影响。结果表明,MOF基隔膜很好地引导了锂离子在锂金属负极的沉积,另外,电极的界面电荷传输性质也得到了改善,界面反应动力学有所提升。在0.5C电流密度下,MOF/PVDF隔膜组装的LTO电池在150圈时的放电容量依旧保持在165~170 mAh g^(-1)左右,相较于普通隔膜电池的157.8 mAh g^(-1)有明显的提升。
基金Funded by the National Natural Science Foundation of ChinaNational 863 Program of China(Nos.50872115and2009AA03Z203)
文摘CeO2 and Ce0.8M0.2O2-d films （M = Mn, Y, Gd, Sm, Nd and La） with （00l） preferred orientation have been prepared on biaxially textured Ni-W substrates by metal organic decomposition （MOD） method. The factors influencing the formation of cracks on the surface of these CeO2 and doped CeO2 films on Ni-W substrates were explored by X-ray diffraction （XRD）, scanning electron microscopy （SEM） analysis, atomic force microscopy （AFM） and differential scanning calorimetry （DSC）. The results indicate that many factors, such as the change of the ionic radii of doping cations, the transformation of crystal structure and the formation of oxygen vacancies in lattices at high annealing temperature, may be related to the formation of cracks on the surface of these films. However, the crack formation shows no dependence on the crystal lattice mismatch degree of the films with Ni-W substrates. Moreover, the suppression of surface cracks is related to the change of intrinsic elasticity of CeO2 film with doping of cations with a larger radius. SEM and AFM investigations of Ce0.8M0.2O2-d （M = Y, Gd, Sm, Nd and La） films reveal the dense, smooth and crack-free microstructure, and their lattice parameters match well with that of YBCO, illuminating that they are potentially suitable to be as buffer layer, especially as cap layer in multi-layer architecture of buffer layer for coated conductors.
基金supported by Samsung Research Fund,Sungkyunkwan University,2006
文摘YBa2Cu3O7-x(YBCO) films were fabricated on an LAO substrate using the trifluoroacetic acid-metal organic deposition(TFA-MOD) method and the effects of the humidity and heat treatment temperatures on the microstructure,degree of texture and critical properties of the films were evaluated.In order to understand the combined effects of the humidity and the calcining and firing temperatures on critical properties,heat-treatment was performed at various temperatures with the other processing variables fixed.The films were calcined at 400-430 ℃ and fired at 750-800 ℃ in a 0-12.1% humidified Ar-O2 atmosphere.The texture was determined by pole-figure analysis.The amount of the BaF2 phase was effectively reduced and a sharp and strong biaxial texture was formed under a humidified atmosphere,which led to increased critical properties.In addition,the microstructure varied significantly with firing temperature but changed little with calcining temperature.The highest IC of 40 A/cm-width,which corresponds to JC value of 1.8 MA/cm2,was obtained for the films fired at 775 ℃(in 12.1% humidity) after calcining at 400-430 ℃.It is likely that the highest IC value is due to the formation of a more pure YBCO phase,c-axis grains,and a denser microstructure.
文摘利用低压金属有机化学气相淀积(LP MOCVD)在Si基片上外延生长ZnO薄膜,制备了两类样品一类是在Si上直接外延ZnO,另一类是在Si上通过SiC过渡层来外延ZnO.根据两类样品的拉曼光谱、x射线衍射、原子力显微图和光致发光的结果,表明ZnO外延薄膜中的张应力对薄膜的结晶状况有着重要的影响,使用SiC过渡层能够有效缓解ZnO薄膜中的张应力,减小缺陷浓度,提高ZnO外延层的质量;然后根据缺陷的形成机制进一步提出,对于ZnO Si,其中较大的张应力导致了高浓度的非辐射复合缺陷的形成,使得样品的紫外和绿峰的发射强度均大大降低;对于ZnO SiC Si,其中较小的张应力导致ZnO薄膜中主要形成氧替位缺陷OZn,从而使发光中的绿峰增强.
